1439811644_Chemists Desk Reference - docshare.tips (2025)

Organic Chemist’s
Desk Reference
Second Edition

Caroline Cooper

CRC Press
Taylor & Francis Group
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Library of Congress Cataloging‑in‑Publication Data
Cooper, Caroline.
Organic chemist’s desk reference / Caroline Cooper. -- 2nd ed.
p. cm.
Rev. ed. of: The organic chemist’s desk reference / P.H. Rhodes. 1995.
Includes bibliographical references and indexes.
ISBN 978-1-4398-1164-1 (pbk. : alk. paper)
1. Chemistry, Organic--Handbooks, manuals, etc. I. Rhodes, P. H. Organic chemist’s desk
reference. II. Title.
QD257.7.R46 2010
547--dc22
Visit the Taylor & Francis Web site at
http://www.taylorandfrancis.com
and the CRC Press Web site at
http://www.crcpress.com

2010017181

To Edward, Charles, and Sebastian

Contents
Preface............................................................................................................................................ xiii
Acknowledgments............................................................................................................................. xv
Chapter 1 The Organic Chemistry Literature................................................................................1
1.1

1.2

1.3
1.4

1.5

Abstracting and Other Current Awareness Services.......................................... 1
1.1.1 Chemical Abstracts............................................................................... 1
1.1.1.1 Printed Products.................................................................... 1
1.1.1.2 CA Volume Indexes and CA Collective Indexes................... 2
1.1.1.3 Chemical Abstracts Index Guide........................................... 5
1.1.1.4 CAS Source Index (CASSI)...................................................6
1.1.1.5 Registry Handbook: Number Section.................................... 6
1.1.1.6 Ring Systems Handbook....................................................... 7
1.1.1.7 Electronic Products................................................................ 7
1.1.2 Chemisches Zentralblatt...................................................................... 10
1.1.3 Index Chemicus................................................................................... 10
1.1.4 Current Contents................................................................................. 10
1.1.5 Chemistry Citation Index.................................................................... 11
1.1.6 Methods in Organic Synthesis and Natural Products Update............. 11
1.1.7 Current Chemical Reactions............................................................... 11
Principal Electronic Dictionaries..................................................................... 11
1.2.1 The Chapman & Hall/CRC Chemical Database................................. 11
1.2.2 Beilstein, CrossFire, and Reaxys........................................................ 12
1.2.2.1 Beilsteins Handbuch der Organischen Chemie................... 12
1.2.2.2 CrossFire Beilstein and Reaxys........................................... 14
1.2.3 Elsevier’s Encyclopedia of Organic Chemistry................................... 15
1.2.4 PubChem............................................................................................. 15
Useful Reference Works and Review Series.................................................... 16
Patents, Including Patent Awareness Services................................................. 19
1.4.1 Markush Structures............................................................................. 19
1.4.2 Patent Numbering................................................................................20
1.4.3 Patent Awareness Services.................................................................. 21
Cheminformatics Companies........................................................................... 22

Chapter 2 Primary Journals......................................................................................................... 23
Endnotes...................................................................................................................... 39
Chapter 3 Nomenclature Fundamentals....................................................................................... 41
3.1

IUPAC Nomenclature....................................................................................... 41
3.1.1 Numbering of Chains.......................................................................... 42
3.1.1.1 Multiplicative Prefixes from Greek and Latin..................... 42
3.1.2 Numbering of Substituents: IUPAC Principles................................... 43
3.1.3 Alphabetisation................................................................................... 43
3.1.4 Other Nomenclature Conventions.......................................................44
vii

viii

Contents

3.2

3.3
3.4

CAS Nomenclature...........................................................................................44
3.2.1 Older Names Encountered in CAS Pre-1972......................................44
3.2.2 Changes in CAS Nomenclature 1977–2006........................................ 47
Types of Name.................................................................................................. 48
Constructing a Systematic Name..................................................................... 50
3.4.1 The Heading Parent............................................................................. 50
3.4.1.1 Choosing the Heading Parent.............................................. 50
3.4.2 Functional Groups............................................................................... 53
3.4.3 Functional Replacement Nomenclature.............................................. 54
3.4.4 Substituents......................................................................................... 55
3.4.5 Modifications....................................................................................... 68
3.4.6 Stereodescriptor(s)............................................................................... 70

Chapter 4 Nomenclature of Ring Systems................................................................................... 71
4.1

4.2
4.3
4.4
4.5
4.6

Ring Systems (General).................................................................................... 71
4.1.1 Indicated Hydrogen............................................................................. 71
4.1.2 Added Hydrogen................................................................................. 72
Bridged Ring Systems...................................................................................... 74
Spiro Compounds............................................................................................. 75
Heterocyclic Ring Systems............................................................................... 76
Ring Assemblies............................................................................................... 77
Ring Fusion Names.......................................................................................... 78

Chapter 5 Nomenclature of Individual Classes of Compound.................................................... 81
5.1

Carbohydrates................................................................................................... 81
5.1.1 Fundamental Aldoses.......................................................................... 81
5.1.2 Fundamental Ketoses..........................................................................84
5.1.3 Modified Aldoses and Ketoses............................................................84
5.1.4 Higher Sugars......................................................................................84
5.1.5 Cyclic Forms: Anomers....................................................................... 85
5.1.6 Glycosides........................................................................................... 85
5.1.7 Disaccharides and Oligosaccharides................................................... 86
5.1.8 Trivially Named Sugars...................................................................... 86
5.2 Alditols and Cyclitols....................................................................................... 87
5.2.1 Alditols................................................................................................ 87
5.2.2 Cyclitols............................................................................................... 88
5.2.2.1 Assignment of Locants for Inositols.................................... 89
5.2.2.2 Absolute Configuration........................................................ 89
5.3 Amino Acids and Peptides...............................................................................90
5.3.1 Amino Acids.......................................................................................90
5.3.2 Peptides...............................................................................................92
5.3.2.1 Recent CAS Peptide Nomenclature Revisions.................... 93
5.4 Natural Products (General)............................................................................... 93
5.5 Steroids.............................................................................................................94
5.6 Lipids................................................................................................................ 95
5.7 Carotenoids....................................................................................................... 95
5.8 Lignans.............................................................................................................96
5.9 Nucleotides and Nucleosides............................................................................ 96
5.10 Tetrapyrroles..................................................................................................... 98

Contents

5.11
5.12
5.13
5.14
5.15

Organoboron Compounds................................................................................ 98
Organophosphorus (and Organoarsenic) Compounds...................................... 98
Azo and Azoxy Compounds........................................................................... 100
Labelled Compounds...................................................................................... 100
Tautomeric Compounds.................................................................................. 101

Chapter 6 Acronyms and Miscellaneous Terms Used in Describing Organic Molecules........ 103
6.1
6.2

Abbreviations and Acronyms for Reagents and Protecting Groups in
Organic Chemistry......................................................................................... 103
Glossary of Miscellaneous Terms and Techniques Used in
Nomenclature, Including Colloquial Terms................................................... 127

Chapter 7 Stereochemistry......................................................................................................... 145
7.1
7.2

7.3
7.4
7.5
7.6

The Sequence Rule: R and S........................................................................... 146
7.1.1 List of Common Groups in CIP Priority Order................................ 148
Graphical and Textual Representations of Stereochemistry.......................... 148
7.2.1 Compounds with One Chiral Centre................................................. 148
7.2.2 Compounds with Two Chiral Centres............................................... 148
7.2.3 Cyclic Structures............................................................................... 149
Chiral Molecules with No Centres of Chirality............................................. 150
7.3.1 Allenes, Biaryls, and Related Compounds........................................ 150
7.3.2 Molecules with Chiral Planes........................................................... 150
E and Z............................................................................................................ 150
The d,l-System............................................................................................... 151
Descriptors and Terms Used in Stereochemistry........................................... 152

Chapter 8 Graphical Representation of Organic Compounds................................................... 159
8.1
8.2

Zigzag Natta Projection.................................................................................. 159
8.1.1 Aromatic Compounds....................................................................... 160
8.1.2 Heterocyclic Compounds.................................................................. 160
Stereochemistry.............................................................................................. 160

Chapter 9 CAS Numbers, InChI, and Other Identifiers............................................................. 163
9.1

9.2
9.3

CAS Registry Numbers.................................................................................. 163
9.1.1 Introduction....................................................................................... 163
9.1.2 Specificity.......................................................................................... 163
9.1.3 Duplicate Registry Numbers............................................................. 164
9.1.4 Registry Numbers with Asterisks..................................................... 164
9.1.5 Racemates......................................................................................... 164
9.1.6 Chronology........................................................................................ 165
InChI.............................................................................................................. 165
Simplified Molecular Input Line Entry System (SMILES)............................ 166

Chapter 10 Molecular Formulae.................................................................................................. 167
10.1 The Hill System.............................................................................................. 167
10.2 Chemical Abstracts Conventions................................................................... 167
10.3 Checking Molecular Formulae....................................................................... 167

Contents

Chapter 11 Chemical Hazard Information for the Laboratory.................................................... 169
11.1 Hazard and Risk Assessment......................................................................... 169
11.1.1 Definitions......................................................................................... 169
11.1.2 Legislation......................................................................................... 170
11.1.3 Workplace Exposure Limits.............................................................. 170
11.2 Physical and Reactive Chemical Hazards...................................................... 170
11.3 Health Hazards............................................................................................... 170
11.4 Handling and Storage of Chemicals............................................................... 172
11.4.1 Gases................................................................................................. 173
11.5 Hazardous Reaction Mixtures........................................................................ 173
11.6 Disposal of Chemicals.................................................................................... 173
11.7 Solvents........................................................................................................... 177
11.7.1 Flammability Classifications............................................................. 177
11.7.2 Health Hazards.................................................................................. 178
11.8 Peroxide-Forming Chemicals......................................................................... 178
11.9 Further Literature Sources............................................................................. 182
11.9.1 Risk and Hazard Assessment (General)............................................ 182
11.9.2 Physical Properties Related to Hazard.............................................. 182
11.9.3 Occupational Exposure Limits.......................................................... 183
11.9.4 Reactive Hazards............................................................................... 183
11.9.5 Toxicology......................................................................................... 184
11.9.6 Material Safety Data Sheets.............................................................. 186
11.9.7 Laboratory Safety.............................................................................. 187
11.9.8 Health and Safety Legislation........................................................... 187
11.9.9 Electronic Sources for Hazard Information...................................... 187
Chapter 12 Spectroscopy............................................................................................................. 189
12.1 Infrared Spectroscopy.................................................................................... 189
12.1.1 Window Materials, Mulling Oils, and Solvents................................ 189
12.1.1.1 Window Materials............................................................. 189
12.1.1.2 Mulling Oils....................................................................... 189
12.1.1.3 Solvents.............................................................................. 190
12.1.2 Characteristic Infrared Absorption Bands........................................ 190
12.2 Ultraviolet Spectroscopy................................................................................ 192
12.2.1 Ultraviolet Cutoff Limits for Solvents............................................... 192
12.2.2 Characteristic Ultraviolet/Visible Absorption Bands....................... 193
12.2.3 UV/VIS Absorption of Dienes and Polyenes.................................... 194
12.2.4 UV/VIS Absorption of α,β-Unsaturated Carbonyl Compounds....... 195
12.3 Nuclear Magnetic Resonance Spectroscopy.................................................. 196
12.3.1 Common Nuclei Used in NMR......................................................... 196
12.3.2 Chemical Shift Data.......................................................................... 196
12.3.3 Coupling Constants...........................................................................204
12.3.3.1 Geminal H–H Coupling (2JH–H).........................................204
12.3.3.2 Vicinal H–H Coupling (3JH–H)...........................................204
12.3.3.3 Long-Range Coupling Constants (3+nJH–H)........................206
12.3.4 Modern NMR Techniques for Structural Elucidation of Small
Molecules..........................................................................................206
12.3.4.1 1D Methods.......................................................................206
12.3.4.2 2D Methods.......................................................................207

Contents

Chapter 13 Mass Spectrometry....................................................................................................209
13.1
13.2
13.3
13.4

Introduction....................................................................................................209
Ionisation Techniques and Mass Spectrometer Systems................................209
Interpreting Mass Spectra and Molecular Mass............................................. 212
Sample Introduction and Solvent Systems for Electrospray Mass
Spectrometry.................................................................................................. 214
13.5 Common Adducts and Contaminants in Mass Spectra.................................. 216
13.6 MALDI Matrices............................................................................................ 218
13.7 Fragmentation Ions and Neutral Losses......................................................... 219
13.8 Natural Abundance and Isotopic Masses of Selected Isotopes and
Nuclear Particles............................................................................................. 222
13.9 Glossary of Abbreviations and Terms Commonly Used in Mass
Spectrometry..................................................................................................224
References.................................................................................................................224
Chapter 14 Crystallography......................................................................................................... 225
14.1
14.2
14.3
14.4
14.5
14.6
14.7
14.8
14.9

Introduction.................................................................................................... 225
Definitions...................................................................................................... 225
Crystallographic Point Groups....................................................................... 226
Space Groups.................................................................................................. 227
Reciprocal Lattice.......................................................................................... 227
Examples of Organic Crystals........................................................................ 227
CIF Data Format............................................................................................. 227
Bragg’s Law and the X-Ray Spectrum........................................................... 230
Crystal Specimen Preparation for X-Ray Analysis........................................ 230
14.9.1 Preparation of X-Ray Powders.......................................................... 231
14.9.2 Preparations of Single Crystals......................................................... 232
14.9.2.1 Protein Crystal Preparation............................................... 232
14.9.2.2 Single-Crystal Preparation (Nonmacromolecules)............ 232
Endnotes.................................................................................................................... 232
Chapter 15 Chromatographic Chiral Separation......................................................................... 233
15.1
15.2
15.3
15.4

Types of Molecular Interactions..................................................................... 233
Diastereomeric Compounds and Complexes.................................................. 233
Chiral Mobile Phases..................................................................................... 234
Chiral Stationary Phases................................................................................ 234
15.4.1 Chiral Separation by Hydrogen Bonding.......................................... 234
15.4.2 Chiral Separation by Inclusion Complexes....................................... 235
15.4.3 Chiral Separation by π-π Interactions, Hydrogen Bonding, and
Ion Pairing......................................................................................... 235
15.4.4 Chiral Separation by Ligand Exchange............................................ 235
15.4.5 Chiral Separation by a Combination of Interactions......................... 235
References................................................................................................................. 236

Chapter 16 Laboratory Data and SI Units................................................................................... 237
16.1 Solvents........................................................................................................... 237
16.1.1 Polarity of Common Laboratory Solvents........................................ 237
16.1.2 Solvents Used for Recrystallisation.................................................. 238

xii

Contents

16.2
16.3

16.4

16.5
16.6
16.7
16.8
16.9

16.1.3 Solvents Used for Extraction of Aqueous Solutions..........................240
16.1.4 Commercial and Common Name Solvents....................................... 241
Buffer Solutions.............................................................................................. 242
Acid and Base Dissociation Constants...........................................................244
16.3.1 First Dissociation Constants of Organic Acids in Aqueous
Solution at 298 K...............................................................................244
16.3.2 Dissociation Constants of Organic Bases in Aqueous Solution
at 298 K............................................................................................. 245
Resolving Agents............................................................................................246
16.4.1 Bases..................................................................................................246
16.4.2 Acids.................................................................................................. 247
16.4.3 Others................................................................................................ 247
Freezing Mixtures..........................................................................................248
Materials Used for Heating Baths..................................................................248
Drying Agents................................................................................................ 249
Pressure-Temperature Nomograph................................................................. 250
SI Units........................................................................................................... 251
16.9.1 SI Base Units..................................................................................... 251
16.9.2 SI-Derived Units................................................................................ 251
16.9.3 Prefixes Used with SI Units............................................................... 252
16.9.4 Conversion Factors for Non-SI Units................................................ 252
16.9.5 Conversion Factors for UK Imperial Units and Other Non-SI
Units of Measurement....................................................................... 253
16.9.6 Further Reading on SI Units............................................................. 254
16.9.6.1 Websites............................................................................. 254

Chapter 17 Languages................................................................................................................. 255
17.1 A German-English Dictionary....................................................................... 255
17.2 Russian and Greek Alphabets........................................................................ 261
Index............................................................................................................................................... 263

Preface
The Organic Chemist’s Desk Reference first appeared in 1995. It was conceived as a companion
volume to the sixth edition of the Dictionary of Organic Compounds (DOC6) but was also available separately. It was compiled by the members of the DOC team, coordinated by Peter Rhodes as
principal author.
The first edition was widely welcomed, but such is the rate of development of the subject that
nearly all the sections are now well out of date. The team that put together DOC6 in the 1990s is still
largely together, and so the present volume consists of a major updating of the first edition, under the
editorship of Caroline Cooper. After changes of ownership of the DOC database, this new edition
appears under the imprint of CRC Press.
The preface to the first edition stated that “success in organic chemistry needs a lively appreciation of the other sciences—and not just other branches of chemistry … in order to make
a success of organic chemistry, the practitioner needs to know so many specialist facts and
methods that the subject can be daunting to a nonspecialist.” This statement is even truer now
than it was then. The divisions between organic chemistry and other disciplines such as biochemistry and materials science have become further blurred, and the phenomenal changes
in informatics since 1995 have impacted on many of the subject areas covered by this book.
New associated subdisciplines—nanochemistry, assembly chemistry, “green” chemistry—have
grown up. Whilst one or two of the subject areas covered by the first edition merely required
some updating, the majority have been heavily revised, and some, notably the chapters on information resources and spectroscopic methods, are completely unrecognisable after a less than
fifteen-year interval.
We hope therefore that the new edition will be welcomed not just by mainstream organic chemists, but by anyone working in one or more of these overlap areas, by anyone else who has to make
occasional use of organic chemistry techniques as part of their daily work, or who needs to interpret
the results of others.
John Buckingham

xiii

Acknowledgments
I should like to thank the following people for their contributions:
Gerald Pattenden (University of Nottingham) gave valuable help at the planning stage.
John Buckingham and Rupert Purchase (Consultants, CRC Press) wrote many of the updated
sections of the book.
The following kindly contributed chapters:
Ross Denton (University of Nottingham)
Matt Griffiths (CRC Press)
Nelu Grinberg (Boehringer Ingelheim Pharmaceuticals, Ridgefield, CT, USA)
Maureen Julian (Virginia Polytechnic Institute, Blacksburg, USA)
James McCullagh (University of Oxford)
Additional sections were written by:
Keith Baggaley and Terry Ward (Consultants, CRC Press)
Janice Shackleton in the London office of CRC Press, organised the typescript and diagrams.
The diagrams were drawn by Trupti Desai and Jenny Francis retyped the material from
the first edition.
Finally, Fiona Macdonald at CRC Press in Boca Raton, commissioned and supervised the
project.

Organic Chemistry
1 The
Literature
1.1 Abstracting and Other Current Awareness Services
There has been a strong trend in recent years toward the merging of previously separate information
products, both in terms of ownership (Chemical Abstracts Service (CAS) being an exception) and
technically (standardisation of search engines so as to facilitate searching across the previously distinct products). As with primary journals, the situation concerning what is free access and what is
subscription only remains complex. The boundary between abstracting services and other information products has also become progressively blurred as (1) many journal publishers, e.g., Elsevier,
have introduced searchable contents files, and (2) products formerly regarded as fulfilling only an
abstracting function have enhanced their features to include substructure search, spectroscopic files,
physical property prediction, etc.
Some of these files are accessible through more than one portal, with different search engines
and charging protocols. For example, Current Contents Search is available on DIALOG charged on
a per-search, per-hit, per-print basis.
Backfiles available in print only (e.g., Index Chemicus pre-1993) are now of very limited use and
likely to be difficult to obtain.

1.1.1 Chemical Abstracts
First published in 1907, Chemical Abstracts (CA) justly claims to be the “key to the world’s chemical literature.” The history and evolution of Chemical Abstracts are described in R. E. Maizell, How
to Find Chemical Information: A Guide for Practicing Chemists, Educators, and Students (New
York, Wiley, 1998, pp. 60–106, 107–39).
Until 2009, Chemical Abstracts Service (CAS; www.cas.org; a division of the American ChemiÂ�
cal Society) produced and marketed Chemical Abstracts in a number of different printed and electronic formats. In 2010 CA print products (with the exception of CA Selects) ceased to be published
and access to CA was restricted to subscribers to the electronic versions: Chemical Abstracts Web
Edition, SciFinder®, and the CAS databases available from STN.
1.1.1.1 Printed Products
For the organic chemist, knowledge of, and access to, the more familiar components of the printed
products of Chemical Abstracts is still desirable: CA abstracts; CA Volume Indexes and CA ColÂ�lecÂ�
tive Indexes; CA Index Guide; CAS Source Index (CASSI); Registry Handbook: Number Section;
the Ring Systems Handbook; and CA Selects.
1.1.1.1.1 Publication Schedule and Content
Until the end of 2009, the printed edition of Chemical Abstracts was published weekly. The abstracts
part of CA categorises the chemical literature into six basic types of entries: (1) serial publications,
(2) proceedings and edited collections, (3) technical reports, (4) dissertations, (5) new book and
audio-visual materials announcements, and (6) patent documents. The abstracts are classified in
1

Organic Chemist's Desk Reference, Second Edition

eighty sections arranged into five broad groupings: Biochemistry (Sections 1–20), Organic Chemistry
(Sections 21–34), Macromolecular Chemistry (Sections 35–46), Applied Chemistry and Chemical
Engineering (Sections 47–64), and Physical, Inorganic and Analytical Chemistry (Sections 65–80).
Each printed weekly issue also contained a Keyword Index, a Patent Index, and an Author Index.
Within any one section, serial publication abstracts, proceedings, edited collection abstracts, and
dissertation abstracts come first; new book and audio-visual materials announcements second; and
patent document abstracts third.
In the early years of publication, CA provided full and complete abstracts (but inferior to
Chemische Zentralblatt; see Section 1.1.2). For the organic chemist, these abstracts contain useful
experimental details and physical properties of chemical substances. With the usual reservations
concerning accuracy, the early abstracts can be a partial substitute for the original literature when
in relatively obscure journals and patents. Around 1950–1970, abstracts became progressively more
findings orientated and did not attempt to abstract all the new data contained in original documents.
Abstracts are now more concise, with text averaging about one hundred words. The first sentence
of a CA abstract highlights the primary findings and conclusions reported in the original document.
The text that follows the first sentence elaborates upon these highlighted findings and emphasises
the following significant data: (1) purpose and scope of the reported work; (2) new reactions, compounds, materials, techniques, procedures, apparatus, properties, and theories; (3) new applications
of established knowledge; and (4) results of the investigation together with the authors’ interpretation
and conclusions. The terminology used in the CA abstract reflects that used by the author(s) in the
original document. Abstracts are suitable for the evaluation of reported research, but the original
documents are consulted for the compilation of the Chemical Abstracts Volume Indexes.
For the patent literature, an abstract is published in CA for the first patent received. Subsequent
patents covering the same invention are not abstracted but entered into the Patent Concordance
organised alphabetically by country (or group of countries) of issue. The abstraction of all new
and existing chemical substances reported in complete patent specifications has been a particularly
useful feature of Chemical Abstracts since its inception. Further details of the patent literature and
patent abstracts are given in Section 1.4.
1.1.1.1.2 CA Abstract Numbers
Since 1967, CA abstracts have been numbered sequentially in each (semiannual) volume of Chemical
Abstracts; the abstract number includes a computer-generated check letter. Before the introduction
of computer-assisted production in 1967, abstracts were located in CA indexes by the sequentially
numbered columns on each page in each issue. The letters a to i were also assigned to every column
to assist in the location of the abstract. Before 1947, a superscript number was used instead of a letter. These older methods did not give each abstract a unique identifier. In SciFinder, all pre-1967
abstracts have been assigned a unique abstract number. These new CA abstract numbers cannot
be used to find abstracts in printed (non-electronic) pre-1967 Chemical Abstracts, and are a potential source of confusion if this distinction between the procedures for locating pre- and post-1967
abstracts is not appreciated.
The symbol pr in printed CA Chemical Subject Indexes denotes “preparation,” and was first
introduced in July–December 1994 (Volume 121). Abstracts are assigned pr on an intellectual basis
by CAS document analysts if the original source material provides information on preparation or
related concepts such as manufacture, purification, recovery, synthesis, extraction, generation, isolation, and secretion.
1.1.1.2 CA Volume Indexes and CA Collective Indexes
CA Volume Indexes are in-depth compilations, whose entries are selected by the CAS indexer from
original documents and not just from the abstracts. Printed editions of the CA Volume Indexes were
published annually until 1962 and, thereafter semiannually (every six months) until 2009.

The Organic Chemistry Literature

Volume Indexes to CA are based on a controlled vocabulary developed by CAS. To provide
chemists with more rapid indexing of the contents of individual CA issues, a form of quick indexing (designated as the Keyword Index) was published with each issue from 1963 to 2009. Keyword
Indexes use a more informal vocabulary than the concise terms in Volume Indexes and are not a
substitute for them.
CA Collective Indexes (CIs) combine into single, organised listings the contents of individual
Volume Indexes. Printed ten-year (decennial) CA Collective Indexes were published for abstracts
issued from 1907 to 1956 (1st CI to 5th CI); five-year (quinquennial) Collective Indexes were published in a print format for abstracts issued from 1957 to 2001 (6th CI to 14th CI). The 15th CI (2002
to 2006) was published in a CD-ROM format only. Table1.1 gives details of the publication dates
and constituent volume numbers for the decennial and quinquennial CA Collective Indexes.
The contents of CA Volume Indexes and CA Collective Indexes are a General Subject Index, a
Chemical Substance Index, a Formula Index, an Author Index, and a Patent Index. The development of these indexes from 1907 to 2006 is traced in Table1.1. Although the convenience of online
and CD-ROM searching has relegated the usage of printed CA Indexes; nevertheless, for some
searches they retain an advantage, for example, in scanning for the known salts and simple derivatives of pharmacologically active substances, searching for stereoisomers and their derivatives, and
checking variants in authors’ names.
1.1.1.2.1 General Subject Index
• The General Subject Index links subject terms, such as reactions, processes and equipment, classes of substances, and biochemical and biological subjects, including plant and
animal species, with their corresponding CA abstract numbers.
• Most entries include a text modification phrase, which further describes aspects of the
topic covered in the original document.
• Before using the General Subject Index, the Chemical Abstracts Index Guide (see Sec
tion 1.1.1.3) should be consulted in order to obtain the correct index headings.
• Prior to 1972, general subjects and chemical substances appeared together in a Subject Index.
1.1.1.2.2 Chemical Substance Index
• The Chemical Substance Index was initiated during the ninth Collective Index period
(1972 to 1976); before 1972, chemical substances and general subjects were in a single
Subject Index.
• This index consists of an alphabetical listing of CA Index Names, each of which identifies
a specific chemical substance linked to the appropriate CA abstract number. Chemical
Substance Indexes (and the earlier Subject Indexes) reflect changes in chemical nomenclature, and in particular the revision of nomenclature implemented for the ninth Collective
Index period. (See Section 3.2 and Chapter 7 for a description of the changes to CA Index
Names and stereochemical descriptors.)
• During the eighth Collective Index period (1967 to 1971), the CAS Chemical Registry
System was introduced (see Section 9.1), and chemical substances were further identified
by their CAS Registry Numbers in the eighth and subsequent printed Collective Indexes
and in Volume Indexes from Volume 71 (July to December 1969) onward.
1.1.1.2.3 Formula Index
• The Formula Index links the molecular formulae of chemical substances with their CA
Index Names, CAS registry numbers, and CA abstract numbers. Molecular formulae are
arranged according to the Hill system order (see Section 10.1).

Table1.1
CA Collective Indexes Content
Collective Index

14tha

13tha

12tha

11tha

10tha

9th

8th

7th

6th

5th

4th

3rd

2nd

1st

2002–
2006
136–145

1997–
2001
126–135

1992–
1996
116–125

1987–
1991
106–115

1982–
1986
96–105

1977–
1981
86–95

1972–
1976
76–85

1967–
1971
66–75

1962–
1966
56–65

1957–
1961
51–55b

1947–
1956
41–50

1937–
1946
31–40

1927–
1936
21–30

1917–
1926
11–20

1907–
1916
1–10

Author Index
Subject Index

•

General Subject Index
Chemical Substance Index
Formula Index
Numerical Patent Index
Patent Concordance
Patent Index
Index of Ring Systems
Index Guide

•
•
•

Years covered
Volumes

•
•
•

•

•
•
•
•
•
•

•
•

•

•
•
•
•
•

•
•
•

•
•

•

•
•

•

Source: Table1.1 is reproduced with the permission of Chemical Abstracts Service, Columbus, Ohio, and the American Chemical Society (CACS). Copyright © 2010. All rights reserved.
a The 15th Collective Index was published in a CD-ROM format only. The 10th to 14th Collective Indexes, respectively, were published both in print and in CD-ROM formats. Beyond the
15th Collective Index, CA content continues to be available in electronic format through the CAS search tools SciFinder® and STN.®
b In 1957, the indexing period was changed from ten years (Decennial Index) to five years (Collective Index).
c The Subject Index was subdivided into the General Subject and Chemical Substance Indexes beginning with the ninth Collective Index period.
d 27-year Collective Formula Index (1920–1946).
e In 1981, the Numerical Patent Index and Patent Concordance were merged into the Patent Index.
f Thirty-year Numerical Patent Index (1907–1936), compiled by the Science-Technology Group, Special Libraries Association (Ann Arbor, MI: J. W. Edwards, 1944).
g The Index of Ring Systems was discontinued after the twelfth Collective Index period. For the 1st to the 6th Collective Indexes, Ring System Information was included in the introduction
to the Subject Index; for the 7th to the 12th Collective Indexes, the Index of Ring Systems was bound with the Formula Index.

Organic Chemist's Desk Reference, Second Edition

15tha

The Organic Chemistry Literature

• Volumes 1–13 of Chemical Abstracts had no Formula Index. Formula Indexes, listing formulae in the Hill order, were produced annually from Volume 14 (1920), and there is a
Collective Formula Index that covers Volumes 14–40 (1920–1946).
1.1.1.2.4 Author Index
• The Author Index is an alphabetical listing of names of authors, coauthors, inventors, and
patent assignees linked to the CA abstract number.
• Both personal and corporate names are included. The name of the first author is linked
with the title of the original document or patent. Coauthors are cross-referred to the name
of the first author.
• A system for the alphabetization and ordering of personal names in CA has evolved, and
is explained in the introduction to the Author Indexes in the Volume Indexes and the
Collective Indexes.
1.1.1.2.5 Patent Index
• The Patent Index is an alphabetical listing of national and international patent offices using
a standardised two-letter code for the country of issue (AD, Andorra, to ZW, Zimbabwe).
Within the listing for each country (or group of countries), patents are arranged in ascending patent number order.
• Each patent number is followed by either a CA abstract number and a complete history of
all equivalent documents, or a cross-reference to the patent number of the first abstracted
patent in the patent family. This feature of the index, detailing a patent family, is the CA
Patent Concordance.
• Separate Numerical Patent Indexes with CA abstract numbers were published for the periods 1907 to 1936 (CA Volumes 1–30) (by the Special Libraries Association) and 1937
to 1946 (CA Volumes 31–40) and 1947 to 1956 (CA Volumes 41–50) (by the American
Chemical Society), respectively. Numerical Patent Indexes became part of CA Collective
Indexes from the sixth CI onward (1957 to 1961). The CA Patent Concordance was started
in 1963, and merged with the Numerical Patent Index in 1981 to form the Patent Index.
1.1.1.3 Chemical Abstracts Index Guide
CA Index Guides explain CA indexing policy and provide cross-references from chemical substance names and general subject terms used in the scientific literature to the equivalent names
and terminology found in Chemical Abstracts. Index Guides are therefore a useful bridge between
the scientific literature and CA General Subject and Chemical Substance Indexes. The first Index
Guide was published with the 8th CI in 1968. Starting in 1992, new editions were issued after the
first, fifth, and tenth volumes of a five-year Collective Index period. Successive editions of the Index
Guide reflect changes in CA policy, content, vocabulary, and nomenclature, and therefore always
replace the immediate preceding edition. The last printed edition of the Index Guide covered the
fifteenth Collective Index period, 2002–2006.
A CA Index Guide contains the following parts:
• The introduction describes cross-references, parenthetical terms, and the indexing policy
notes listed in the main part of the Index Guide.
• The Index Guide, the main part of the publication, is an alphabetical sequence of chemical substance names selected from the literature (including trivial names used for natural products, International Nonproprietary Names (INN), trade names, and code names)
with cross-references to the chemical substance names used in CA Chemical Substance
Indexes. CAS registry numbers are provided as part of the cross-reference entry. Also in
this part of the Index Guide (beginning in 1985) are the CA General Subject Index headings (excluding Latinised genus and species names) and diagrams for stereoparents.

Organic Chemist's Desk Reference, Second Edition

• Appendix I: Hierarchies of General Subject Headings lists the general and specific headings that have been developed by CAS for the General Subject Index and the hierarchies
employed for these headings.
• Appendix II: Indexes to Chemical Abstracts: Organisation and Use is a comprehensive
account of the organisation, and relationships, of the CA Chemical Substance Index, CA
General Subject Index, CA Formula Index, and CA Index of Ring Systems. This appendix
also describes the CAS Chemical Registry System and the criteria applied in selecting CA
index entries.
• Appendix III: Selection of General Subject Headings discusses the content of the CA
General Subject Index.
• Appendix IV: Chemical Substance Index Names describes the CAS rules for naming substances entered in the CA Chemical Substance Indexes and given CAS registry numbers.
For the organic chemist especially, this appendix is a detailed explanation of CAS rules for
naming organic chemical substances and the CAS convention for stereochemical descriptors. CAS revised its rules for naming chemical substances during the ninth and fifteenth
Collective Index periods, respectively, and adopted new rules for stereochemical descriptors during 1997–1998. These changes are explained in Chapters 3 and 7.
1.1.1.4 CAS Source Index (CASSI)
The Chemical Abstracts Service Source Index, commonly referred to as CASSI, gives details of
the journals and related literature cited in Chemical Abstracts since 1907. In addition, CASSI contains entries for those publications covered by Chemische Zentralblatt and its predecessors from
1830–1969 and the publications cited by Beilstein prior to 1907. The most recent printed cumulative
edition of CASSI spanned the period 1907–2004. Printed supplements to CASSI were published
quarterly from 2005 to 2009. The fourth quarterly supplement each year cumulated and replaced the
preceding three supplements, and was effectively an annual update. Publication of the printed edition of CASSI ceased in 2009, but CASSI remains available and updated in a searchable CD-ROM
format (CASSI on CD, first produced in the 1990s).
Entries in CASSI include the following information: complete title for a serial or a nonserial
publication, abbreviated title, variant title, ISSN, ISBN, translation of the title (for some foreign language titles only), name and address of the publisher or sales agency where the publications may be
obtained, and a history of the serial publication, such as predecessor and successor titles. Entries in
CASSI are arranged alphabetically according to the abbreviated form of the serial or nonserial title.
For the organic chemist, CASSI is particularly useful for providing:
• The recognised and authoritative abbreviations of journals and other publications in the
chemistry literature.
• The complete journal titles for abbreviations used for serials and nonserials in Chemical
Abstracts from 1907 to 2002. (Starting with Volume 136 (2002), Chemical Abstracts
began to quote the full journal or publication title as part of the abstract instead of the
CASSI abbreviation.)
CASSI abbreviations for about fifteen hundred leading journals are listed on a free website
(CAplus Core Journal Coverage List). Also on the web is the CAS Source Index (CASSI) Search
Tool (http://cassi.cas.org/search.jsp).
1.1.1.5 Registry Handbook: Number Section
Following the introduction of the system of CAS registry numbers in 1965 (see Chapter 9), CAS
published the Registry Handbook—Number: Section. The initial handbook covered the period
1965–1971 (registry numbers 35-66-5 to 33913-68-7). Annual supplements of registry numbers
were published from 1972 to 2001 (registry numbers 33913-69-8 to 380148-63-0), when publication

The Organic Chemistry Literature

of the printed version ceased. There was also a series of Registry Handbook: Registry Number
Updates published from 1965 to 2001, which gave details of discontinued registry numbers and
any updates.
Entries in the Registry Handbook list CAS registry numbers in numerical sequence, and their
associated CA Index Names and molecular formulae. Concomitantly with the printed edition, CAS
developed an online searchable database of registry numbers, CAS Registry. By April 2010, this
database contained the details of over 53,000,000 organic and inorganic substances and 61,722,079
sequences, and the most recent CAS registry number was 1217435-73-8.
1.1.1.6 Ring Systems Handbook
See Section 1.3 and Chapter 4 for more information.
1.1.1.7 Electronic Products
1.1.1.7.1 Chemical Abstracts on CD-ROM
The tenth to fifteenth CA Collective Indexes and Abstracts (1977–2006) were produced in a CD-ROM
format, and annual updates were issued from 2007. These CD-ROM versions of Chemical Abstracts
incorporate a number of useful and browsable search indexes with Boolean functionality, some of
which are not in the printed product:
•
•
•
•
•
•
•
•
•
•
•
•
•

Word Index
CAS Registry Number Index
Author Index
General Subject Index
Patent Index
Formula Index
Compound Index
Chemical Abstract Number Index
Organisation
Journal Title Index
Language Index
Year of Publication Index
Document Type Index

1.1.1.7.2 Chemical Abstracts Web Edition
Chemical Abstracts web edition was introduced in 2008 and is an alternative web-based product for
accessing Chemical Abstracts. The web edition has the following features:
• Electronic access to fully indexed records in CAS databases corresponding to the customer’s subscription period to Chemical Abstracts from 1996 to the present
• Multiple ways to browse information, including:
• Bibliographic indexes
• Subject indexes
• Substance indexes
• Basic and advanced search capabilities with refine options
• Capability to search across multiple years
• Option to save answers locally or on the CAS server
• Modern, browser-based interface
1.1.1.7.3 SciFinder
SciFinder is the preferred portal to access chemical information from the CAS databases and
is designed for use by chemists in commercial organisations. SciFinder Scholar is a version for

Organic Chemist's Desk Reference, Second Edition

universities and academic institutions that lacks some supplementary features. Both can be searched
by substructure in addition to other methods.
In 2009, there were two ways to access: from a client version installed on a computer or via web
access. The client version is being phased out as the web version is being developed. Both versions
have the same functionality. Advantages of SciFinder include the ability to combine answer sets
and the ability to see all the substances linked to an abstract in a grid layout. Clicking on a substance structure or registry number allows the user to modify the structure for future searches or to
explore reactions. SciFinder also provides access to the full text of the article through the ChemPort
Connection. This allows the user to directly access the article when permissions for access are
enabled or to purchase the article when they are not enabled.
Table1.2 shows the databases and information available from SciFinder.
1.1.1.7.4 CAS Databases Available on STN
STN is an online database service jointly owned by CAS and FIZ Karlsruhe. Chemical Abstracts
Service provides a range of online databases covering chemistry and related sciences (see also
Table1.2):
CAplusSM covers the literature from 1907 to the present, plus more than 133,000 pre-1907 journal records and more than 1,250 records for U.S. patents issued from 1808 to 1859. Includes
article references from more than ten thousand major scientific worldwide journals, conference proceedings, technical reports, books, patents, dissertations, and meeting abstracts.
CAS Registry is a structure and text-searchable database containing information on approximately 46 million organic and inorganic substances and over 60 million sequences with
associated CAS registry numbers.
CASREACT ® is a structure and text-searchable organic chemical reaction database containing more than 17 million single- and multistep reactions with more than six hundred thousand records from journal articles and patents with reaction information. Coverage is from
1840 to the present.
CHEMCATS ® is a database of more than 34 million commercially available chemicals from
more than nine hundred suppliers and one thousand catalogues.
CHEMLIST ® is a regulated chemicals listing. Regulated substances listed on the Environmental
Protection Agency Toxic Substances Control Act Inventory, the European Inventory
of Existing Commercial Chemical Substances, and the Domestic and Nondomestic
Substances List from Canada are well covered, as well as other lists of hazardous substances. More than 249,000 substances are listed.
CIN ® (Chemical Industry Notes) contains bibliographic and abstract information from journals, trade magazines, and newspapers.
1.1.1.7.5 CA Selects
Issued biweekly, CA Selects Plus, CA Selects, and CA Selects on the Web are current awareness
bulletins, in print and electronic format, comprising the CA abstracts of all papers on a particular
topic covered in Chemical Abstracts. No indexes are provided. There are over two hundred topics
available. Those of interest to organic chemists include:
•
•
•
•
•
•

Amino acids, peptides, and proteins
Asymmetric synthesis and induction
Beta-lactam antibiotics
Carbohydrates (chemical aspects)
Natural product synthesis
New antibiotics

The Organic Chemistry Literature

Table1.2
SciFinder Content
Database

CAplusSM

MEDLINE®

CAS REGISTRYSM

CASREACT®

Content
Reference Databases
Literature from 1907 to the present plus selected pre-1907 references. Sources include journals,
patents, conference proceedings, dissertations, technical reports, books, and more.
CAplus covers a wide spectrum of science-related information, including chemistry, biochemistry,
chemical engineering, and related sciences.
Biomedical literature from more than 4,780 journals and 70 countries, covering literature from 1950 to
the present.
Structure Database
Specificchemical substances, including organic and inorganic compounds, sequences, coordination
compounds, polymers, and alloys covering 1957 to the present, with some classes going back to
the early 1900s.
Reaction Database
Reaction information for single- and multiple-step reactions from 1840 to the present.

CHEMCATS®

Commercial Source Database
Chemical source information, including supplier addresses and pricing information derived from
current chemical catalogues and libraries, retrieved for individual substances.

CHEMLIST®

Regulatory Database
Regulatory information records from 1979 to the present, including substance identity information,
inventory status, sources, and compliance information.

Information available from SciFinder includes:
Content Area
References

Substances

Information Available
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•

Title
Author/editor/inventor
Company name/corporate source/patent assignee
Publication year
Source, publication, date, publisher, volume, issue, pagination, CODEN, ISSN
Patent identification, including patent, application, priority, and patent family information
Abstract of the article or patent
Indexing
Supplementary terms
Citations
Substances, sequences, and reactions discussed within the document
Chemical name
CAS Registry Number®
Molecular formula
Structure diagram
Sequence information, including GenBank® and patent annotations
Property data, including spectral diagrams
Commercial source information from chemical supplier catalogs
Regulatory information
Editor notes
Documents in which the substance is referenced
Reactions in which the substance participates
(continued on next page)

Organic Chemist's Desk Reference, Second Edition

Table1.2 (continued)
SciFinder Content
Content Area
Reactions

Information Available
• Reaction diagrams, including reactants, products, reagents, catalysts, solvents, and step notes
• Document in which the reaction is referenced
• Additional substance details, reactions, references, regulatory information, and commercial
source information for all reaction participants
• Notes

Source: Table1.2 is reproduced from the Chemical Abstracts Service, Columbus, Ohio, and the American Chemical Society
(CACS). Copyright © 2010. All rights reserved..
Note: SciFinder retrieves information contained indatabasesproduced by Chemical Abstracts Service (CAS) as well as in
the MEDLINE® database of the National Library of Medicine (NLM).

•
•
•
•
•
•
•
•
•
•

Novel natural products
Novel sulfur heterocycles
Organic stereochemistry
Organofluorine chemistry
Organophosphorus chemistry
Organosulfur chemistry (journals)
Porphyrins
Prostaglandins
Synthetic macrocyclic compounds
Steroids (chemical aspects)

Detailed information about CAS products can be found at www.cas.org.

1.1.2 Chemisches Zentralblatt
A German-language abstracting publication that ran from 1830 to 1969. For the period 1907–1969
its coverage and quality of abstracts were usually superior to CAS, and it may still be useful occasionally. An electronic file with advanced search capabilities is available from FIZ CHEMIE Berlin
on a subscription basis (www.fiz-chemie.de/zentralblatt).
Review: Weiske, C., Chem. Ber., 106, I–XVI, 1973.

1.1.3 Index Chemicus
Founded by the Institute for Scientific Information (ISI), now owned by Thomson-Reuters, Index
Chemicus is now part of the Web of Science service, which is in turn part of the Web of KnowledgeSM
(www.thomsonreuters.com/products_services/scientific/Web_of_Science). The electronic file goes
back to 1993 and contains data on 2.6 million compounds. The Web of Science abstracts over 10,000
journals; separate figures are not available for chemistry, but the coverage can be browsed free online.

1.1.4 Current Contents
Also now part of the Web of Science (formerly an ISI product; the electronic version is called
Current Contents Search®, which is updated weekly. Gives contents and bibliographic data for
papers published in 7,600 scientific journals (chemistry titles not separately counted). Includes prepublication access to some electronic journals.

The Organic Chemistry Literature

1.1.5 Chemistry Citation Index
Also part of the Web of Science, this is the successor to the ISI Citation Index and uniquely allows
forward searching from a given paper to all subsequent papers that have cited it. The electronic version is called Science Citation Index Expanded. It covers 6,400 journals across all of science, mostly
English language. It is possible to subscribe to the Citation Reports service, which sends automatic
reports of citation activity relevant to a particular paper or papers.

1.1.6 Methods in Organic Synthesis and Natural Products Update
These two bulletins are issued monthly by the Royal Society of Chemistry, and each contain about
250 items per issue. Methods in Organic Synthesis (MOS) gives reaction schemes for new synthetic
methods reported in the current literature, while Natural Products Update (NPU) covers papers
dealing with the isolation, structure determination, and synthesis of natural products. In each case,
subscribers have access to the searchable web version.

1.1.7 Current Chemical Reactions
Also part of the Web of Science. Abstracts 1 million reactions back to 1986.
See also synthesis databases listed below, e.g., Science of Synthesis.

1.2 Principal Electronic Dictionaries
This heading covers tertiary databases that are highly edited and which contain assessed data on
compound properties, reactions, etc. Clearly there are trade-offs between breadth of coverage,
degree of editing, and currency. However, modern electronic methods make it possible to update
a large data set within a reasonable period of the appearance of new information in the primary
literature, and allow its reconciliation with existing data.

1.2.1 The Chapman & Hall/CRC Chemical Database
This database was set up in 1979 to produce the fifth edition of the Dictionary of Organic Compounds
(DOC), a printed dictionary founded by I. M. Heilbron in 1934. It was subsequently published in
electronic form and considerably expanded, especially into natural products and organometallic
and inorganic compounds. The sixth edition of DOC (1995) was the last in printed form. Database
segments are now available in DVD (formerly CD-ROM) format, as a web version, and for in-house
loading by arrangement.
The two principal electronic subsets of the database now available are the following:
The Dictionary of Natural Products (DNP) is a comprehensive resource, now containing
approximately 200,000 compounds organised into approximately 80,000 entries. DNP contains highly edited taxonomic information, and a recently introduced feature is hyperlinking
to the Catalogue of Life, the most authoritative taxonomic resource.
The Combined Chemical Dictionary (CCD) contains every compound on the database
(approximately 500,000), including natural products, inorganics, and organometallics, but
without some of the specialist features of DNP, such as the Catalogue of Life link.
The coverage of CCD in respect to general organics consists of the following:
• The basic fundamental organic compounds of simple structure that are frequently
required as starting materials, and which have usually been the subject of extensive
physicochemical study
• Compounds with a well-established use, e.g., pesticides and drugs in current use

Organic Chemist's Desk Reference, Second Edition

• Laboratory reagents and solvents
• Other compounds with interesting chemical, structural, or biological properties,
including intriguing molecules that have been specially synthesised in order to investigate their chemical and physical properties
CCD is very easy to use and especially valuable for getting an overview of particular
compounds or types of compounds, and in teaching applications. The careful selection of
references (labelled to show their relevance) and user-friendly nomenclature (with extensive synonym range) takes the user straight to the best literature, and the whole database
is kept topical. It is not intended as a comprehensive resource but is often the best place to
start the search process. Particularly valuable features are the extensive coverage of CAS
numbers and hazard/toxicity information.
The following subset dictionaries have been published in recent years from the Chapman & Hall/
CRC database, and are intended as desktop references for the specialist worker. Now published
by CRC Press each (except the older titles) consists of a large, single-volume printed dictionary
accompanied by a fully searchable CD-ROM uniform in format and search capabilities (including
substructure searching) with the main database. A new interface for text and structure searching by
ChemAxon was released in 2009.
Dictionary of Alkaloids with CD-ROM, 2nd ed., ed. J. Buckingham et al., CRC Press, 2010.
Contains enhanced entries for all alkaloids from the Chapman & Hall database (20,000+
alkaloids, comprehensive record).
Dictionary of Carbohydrates with CD-ROM, 2nd Ed. ed. P. M. Collins, Chapman & Hall/
CRC Press, 2005. Contains all the carbohydrates from the Chapman & Hall database.
Dictionary of Food Compounds with CD-ROM, ed. S. Yannai, Chapman & Hall/CRC Press,
2003. Provides information on natural food constituents, additives, and contaminants.
Dictionary of Marine Natural Products with CD-ROM, ed. J. W. Blunt and M. H. G. Munro,
Chapman & Hall/CRC, 2007. Comprehensive coverage of marine natural products known
to 2006.
Dictionary of Organophosphorus Compounds, ed. R. S. Edmundson, Chapman & Hall,
1988. Structures, properties, and bibliographic data for 20,000 organophosphorus compounds (print only, no CD-ROM).
Dictionary of Steroids, ed. D. N. Kirk et al., 2 vols., Chapman & Hall, 1991. Covers over
15,000 steroids in 6,000 entries (print only, no CD-ROM).
(See also the Lipid Handbook in Sections 1.3 and 5.6.)
For more information about subscriptions/prices or to ask for a trial of Dictionary of Natural
Products, Combined Chemical Dictionary, or other chemistry products, contact e-reference@Â�
taylorandfrancis.com.

1.2.2 Beilstein, CrossFire, and Reaxys
1.2.2.1 Beilsteins Handbuch der Organischen Chemie
Beilsteins Handbuch der Organischen Chemie evolved from the original two-volume first edition
compiled by Friedrich Konrad Beilstein (1838–1906) and published between 1881 and 1883 to a
multi-volume behemoth, which, when publication of the printed version was terminated in 1998,
spanned the literature of organic chemistry in 503 volumes and contained 440,814 pages.
The fourth edition and its supplements, published from 1918 onward, is the definitive (and last)
printed edition and is the record of all organic compounds synthesised before December 31, 1979.

The Organic Chemistry Literature

Table1.3
The Series of the Beilstein Handbook
Series
Basic Series (Hauptwerk)
Supplementary Series I
Supplementary Series II
Supplementary Series III
Supplementary Series III/IV
Supplementary Series IV
Supplementary Series V
a

Abbreviation

Years Covered

H
EI
E II
E III
E III/IVb
E IV
EV

Up to 1910
1910–1919
1920–1929
1930–1949
1930–1959
1950–1959
1960–1979

Coloura
Green
Dark red
White
Blue
Blue/black
Black
Red

The colour refers to the colour of the label on the spine of the books. Series H
to E IV are bound in brown. Series E V is bound in blue.
Volumes 17–27 of Supplementary Series III and IV covering the heterocyclic
compounds are combined in a joint issue.

(It does not cover natural products that have not been synthesized.) In addition to the main work
(literature 1771–1910), there are five supplementary series, as shown in Table1.3.
E V is in English, previous series are in German. The property data included for the common and
frequently handled chemicals are exhaustive, carefully edited, and extremely valuable.
In the printed version, each series comprises twenty-seven volumes (or groups of volumes)
known as Bands 1–27 according to functional group seniority. Bands 1–4 cover alicyclic compounds, 5–16 alicyclic, and 17–27 heterocyclic. Groups of compounds are allocated a Beilstein
system number that allows forward searching for the same and related compounds in earlier or later
supplementary series. However, knowledge of how to use printed Beilstein in this way is largely
redundant in the electronic version, and in any case most users of the printed version would now
use the Formula Indexes. (The Name Indexes are not recommended because of many complex
nomenclature changes since 1918). There is a three-volume index covering the Hauptwerk and
Supplements E I and E II that is still valuable for locating information from the pre-1920 literature
that is not covered by CAS. In later supplements the bands are separately indexed, but there is also
the Centennial Index published in 1991 and 1992 in thirteen volumes, which covers the Hauptwerk
and Supplements E I to E IV inclusive. These indexes use the Hill system (see Chapter 10), although
it should be noted that earlier individual volumes use the Richter system (e.g., O precedes N). The
indexes also refer to the page numbers, not to the Beilstein system numbers.
Printed Beilstein can also be tricky to use because compounds are often treated as derivatives of
an unexpected parent, so that, for example, 2-methylfuran and 3-methylfuran do not occur together;
2-methylfuran is first followed by numerous halogeno-, azido-, etc., 2-methylfurans. Various user
guides to the printed Beilstein have been published at different times.
Although the later editions of the Handbuch were far larger than Beilstein’s own versions, they
remained true to his vision of a comprehensive, reliable coverage of the organic literature for many
decades. Eventually, however, the sheer enormity of the chemical literature rendered such perfection impossible, and the Handbuch began to lag behind the literature, especially during and after
the disruptions caused by World War II. The fourth supplement covering the literature through 1959
was not fully completed until 1987. The fifth supplement, now in English, essentially abandoned the
idea of comprehensiveness and settled for a selective coverage of the heterocyclic literature between
1960 and 1979. It finally ceased publication in print in 1998, nearly twenty years after its literature
closing date.
Beilstein’s work was resurrected by conversion of the printed work into an electronic format,
the Beilstein Database. Details of this transition and the earlier marketed electronic formats of the

Organic Chemist's Desk Reference, Second Edition

Beilstein Database are described in The Beilstein System: Strategies for Effective Searching, ed. S. R.
Heller (Washington, DC: American Chemical Society, 1997). In the 1990s, the Beilstein Institute
together with MDL produced an Internet-based client-server system of the Beilstein Database,
CrossFire Beilstein, which is now owned and updated by Elsevier Information Systems, Frankfurt.
1.2.2.2 CrossFire Beilstein and Reaxys
CrossFire Beilstein is available to subscribers as part of the CrossFire Database Suite. This package
consists of CrossFire Beilstein, CrossFire Gmelin, and Patent Chemistry Database. Since January
2009, the contents of these three databases have been merged and are accessible through a new webbased interface, Reaxys (Table1.4).
For organic chemists, the core of the information available through CrossFire Beilstein and
Reaxys is the data from Beilsteins Handbuch der Organischen Chemie from the Basic Series to
Supplementary Series IV covering the literature from 1779 to 1959. The complete Handbuch information is available for more than 1.1 million compounds. In addition, for the primary literature from
1960 to 1979, there are data on about 3 million more compounds.
Searching CrossFire Beilstein is fairly intuitive. Predefined search forms allow for searches on
the following information:
•
•
•
•
•
•
•
•
•

Bibliographic data
Substance identification data
Molecular formula search
Reaction data
Physical data (including melting and boiling point, density, refractive index)
Spectroscopic data
Pharmacological data
Ecotoxicological data
Solubility data

In addition there is a Structure/Reaction search option. Guides and a “Help” button provide
detailed information for searching CrossFire Beilstein.
To avoid obtaining multiple hits, either a combination of search terms is recommended or, preferably, a search using structure or substructure.
Table1.4
Content Information of Reaxys
Origins
Subject scope
Time span

Special notes

Beilstein

Gmelin

Patent Chemistry Database

Beilstein Handbook of Organic
Chemistry, 4th edition
Organic chemistry

Gmelin Handbook of Inorganic
and Organometallic Chemistry
Inorganic and organometallic
chemistry
Journals from 1772 to 1995

U.S. Patent and Trademark Office
and esp@cenet
Organic chemistry and life
sciences
U.S. patents from 1976, and WIPO
and European patents from 1978

Limited to ~100 inorganic
journals

Created by Elsevier to expand
patent coverage of Beilstein with
the same literature selection and
extraction criteria

Journals since 1771, and .
patent publications from
1869 to 1980
At present (2009) updates
limited to abstracting ~200
organic synthesis journals

Source: Reproduced from N. Xiao, Issues in Science & Technology Librarianship, No. 59 (Summer 2009). With
permission.

The Organic Chemistry Literature

Additional tools in Reaxys enhance the structure searching options and include:
•
•
•
•
•

A synthesis planner to design the optimum synthesis route (see below)
Generation of structure from names, InChI (see Section 9.2) keys, or CAS registry numbers
Linkage to Scopus and eMolecules (a free website for commercially available compounds)
Search result filters by key properties, synthesis yield, or other ranking criteria
Multistep reactions to identify precursor reactions underlying synthesis of target compounds

Each chemical reaction has a Reaxys Rx-ID, which is a unique registry number in this database,
and is fully searchable. The table view of the records listed also presents possible synthesis route(s)
of reactions with possible yield, conditions, and references. Results can be sorted, and redefined
by filters.
Similar to a chemical reaction and its Rx-ID, a substance also has its unique Reaxys registry
number (Rx-RN), which is assigned to each substance when it is registered for the first time in the
database. If a CAS registry number is available for the compound, it will be displayed as a part of
the property data. The availability of a substance’s CAS registry number enables users to easily
identify specific compounds between Reaxys and CAS databases (e.g., SciFinder Scholar, STN,
SciFinder web), which are now e-linked.
One of the special features of Reaxys is “Synthesis Plans,” which integrates reactions and substances, as well as providing literature search results within one interface. Users can take advantage
of this feature to develop better search synthesis strategies.
After selecting a specific substance or reaction, users can:
•
•
•
•
•

Transfer the search result (e.g., a substance or a reaction) to the “Synthesis Plans” tab
Follow “quick hits” to search for optimum or alternative synthesis routes
“Synthesise” to get all relevant synthetic routes for desired product
“Modify” to get all alternative synthetic routes for desired product
Further refine results by applying analytical filters

With its additional functionalities compared with CrossFire Beilstein, Reaxys allows users to
identify specific chemicals more easily, and optimise synthesis routes with detailed reaction information. Selected reactions and substances can be exported into different file formats, and selected
references can be exported into reference management software.
(The historical information in this section is reproduced, with permission, from the University
of Texas at Austin Library website.)

1.2.3 Elsevier’s Encyclopedia of Organic Chemistry
Edited by F. Radt (Elsevier, 1940–1956; Springer, 1959–1969) and with similar coverage and style
to Beilstein. It is in English but only Volumes 12–14, condensed carboisocyclic compounds, were
published. Publication was suspended in 1956, but further supplements were published by Springer
until the steroid sections in Beilstein appeared. It provides a good entry to the old literature on
naphthalenes, anthracenes, etc., but is now difficult to find and is not available electronically.

1.2.4 PubChem
A free-access database of small molecules (fewer than one thousand atoms and one thousand bonds),
compiled by the U.S. National Center for Biotechnology Information (NCBI), a component of the
National Institutes of Health (NIH) (pubchem.ncbi.nlm.nih.gov).

Organic Chemist's Desk Reference, Second Edition

To date it includes data on 37 million fully characterised compounds as well as mixtures, complexes, and uncharacterised substances. It provides information on chemical properties, structures
(including InChI and SMILES (see Section 9.3) strings), synonyms, and bioactivity.

1.3 Useful Reference Works and Review Series
This list comprises some of the more important reference books and review series dealing with
organic chemistry. For major abstracting services, such as Chemical Abstracts, and dictionaries,
such as the Dictionary of Natural Products, see the preceding sections.
Many of the larger reference works given here have made, or are making, the transition to electronic access. In assessing the worth of the latest available electronic version, which may not carry
a definite edition number, it is important to check the thoroughness of the updating process and
ensure that a reputation founded on a large backfile continues to be justified in terms of currency.
Accounts of Chemical Research, American Chemical Society. Wide-ranging review journal
with a bias toward interdisciplinary methods and techniques.
ACS Symposium Series, American Chemical Society, produced and marketed by OUP
America. Ongoing series of books developed from the ACS technical divisions symposia.
Topics tend toward industrial chemistry but include some organic topics.
Advanced Organic Chemistry, 5th ed., ed. F. A. Carey and R. J. Sundberg, 2 vols.,
Springer, 2008.
Advances in Heterocyclic Chemistry, ed. A. Katritzky, Academic Press. A review series that
reached vol. 96 by 2008.
Alkaloids, Chemistry and Biology, ed. R. H. F. Manske, then A. Brossi, then G. A. Cordell;
Academic Press, then Wiley, then Elsevier; 1949–. The leading review series devoted to
alkaloids.
Atlas of Stereochemistry, 2nd ed., ed. W. Klyne and J. Buckingham, 2 vols. Supplement by
J. Buckingham and R. A. Hill, 1986. The standard reference on absolute configurations,
though now rather out of date.
CAS Ring Systems Handbook. The last edition of this major reference work was published
by CAS in 2003 with semiannual supplements until it was discontinued in 2008. The first
part of the handbook, the Ring Systems File, contains structural diagrams and related data
for 133,326 unique representative CA index ring systems and 4,492 caged systems (polyboranes, metallocenes, etc.). Information accompanying each ring system includes a Ring
File number, the CAS registry number, a structural diagram illustrating the numbering
system, the current CA name, and the molecular formula. The ring systems are arranged
by their ring analysis, which is given before each group of ring systems having a common
ring analysis. The handbook also includes the Ring Formula Index and the Ring Name
Index, which are designed to provide access to the contents of the Ring System File. This
handbook is particularly useful for accessing the numbering systems used in complex molecules. (See Section 4.1 for details of the use of the handbook.)
Chemical Reviews, American Chemical Society. Monthly authoritative reviews across the
whole of chemistry.
Chemical Society Reviews, Royal Society of Chemistry. Monthly reviews across the whole
of chemistry.
Chemistry of Functional Groups, ed. S. Patai, Z. Rappoport, and others, Wiley, 1964–. An
extensive multivolume series. Each volume covers all aspects of a particular class of compound defined by functional group. Recent volumes are now available online and the titles
of the complete series are at http://eu.wiley.com and http://www3.interscience.wiley.com.

The Organic Chemistry Literature

A summary of the content of the series may be found in Patai, S., Patai’s 1992 Guide to
the Chemistry of Functional Groups, New York, Wiley, 1992.
Chemistry of Heterocyclic Compounds (“Weissberger”), published by Wiley. An extensive
series covering heterocyclic compounds class by class with supplementary volumes as
desirable. Each volume covers one or more ring systems. Titles of the complete series
1950–2008 may be found at http://www3.interscience.wiley.com.
Comprehensive Heterocyclic Chemistry III, 15 vols., Elsevier, 2008. Several authors. Large
but gives a faster and more general survey than the Weissberger series. Available electronically at www.sciencedirect.com.
Comprehensive Medicinal Chemistry II, ed. D. Triggle and J. Taylor, 8 vols., Elsevier, 2006.
Comprehensive Organic Chemistry, ed. D. H. R. Barton and W. D. Ollis, 6 vols. Pergamon, 1979.
Comprehensive Organic Functional Group Transformations, ed. A. R. Katritzky, O. MethCohn, and C. W. Rees, 7 vols., Pergamon, 1995; Comprehensive Organic Functional
Group Transformations II, ed. A. R. Katritzky and R. J. K. Taylor, 7 vols., Elsevier, 2004.
Comprehensive Organic Synthesis, ed. B. M. Trost and I. Fleming, 9 vols., Pergamon/
Elsevier, 1992.
CRC Handbook of Chemistry and Physics, 90th ed., ed. D. R. Lide, 2009. Well-known convenient one-volume reference, updated annually. Extensive tables of physicochemical properties across the whole of chemistry and physics, including common organic compounds.
Encyclopedia of Reagents for Organic Synthesis, ed. L. A. Paquette and others, 8 vols., Wiley,
1995. The second edition was published in February 2009. The original printed publication
reviewed ca. 3,500 reagents and the new edition 4,111 reagents and 50,000 reactions; figures for the current electronic version are not available. Available online as e-EROS at
www3.interscience.wiley.com. There is also Handbook of Reagents for Organic Synthesis
by the same authors.
Fieser’s Reagents for Organic Synthesis, Wiley. An alphabetical listing of reagents used in
syntheis. Began with a single volume in 1967 by Louis and Mary Fieser, followed by
updates. Vol. 24, ed. T. Ho, 2008. Available as a set of volumes (1–23) with cumulative
index. Not available online.
Greene’s Protective Groups in Organic Synthesis, 4th ed., ed. T. W. Greene and P. G. M.
Wuts, Wiley-Interscience, 2006.
Kirk-Othmer Encyclopedia of Chemical Technology, 5th ed., 26 vols., Wiley, 2004–2007, and
Ullmanns Encyclopedia of Industrial Chemistry, 6th ed., 40 vols., Wiley, 2003. These two
major competing/complementary encyclopedias are now owned by the same publisher, and
a merger would seem likely in due course. Ullmanns was originally published in German
(now English) and has a European/Japanese focus; Kirk-Othmer is published in English
with a North American bias. Despite their titles, they contain much pure chemistry. They
are available online from www.interscience.wiley.com. For a short review comparing and
contrasting them, see C. Craig, www.istl.org/06-spring/databases4.
The Lipid Handbook with CD-ROM, 3rd ed., ed. F. D. Gunstone, J. L. Harwood, and A. J.
Dijkstra, CRC Press, 2007. A large one-volume reference work in two parts; a 780-page
monograph on lipid chemistry, followed by a 617-page dictionary that is a reprint of all
lipid entries from the CRC database (see Section 1.2.1), also searchable on the CD-ROM
version in a format uniform with the main database.
March’s Advanced Organic Chemistry, 6th ed., ed. M. B. Smith and J. March, Wiley, 2007.
Martindale, The Complete Drug Reference, 36th ed., ed. S. Sweetman, 2 vols., Pharmaceutical
Press, 2009. Monographs on drugs and ancillary substances, 5,820 described. Also available on CD-ROM, and online at www.medicinescomplete.com.
The Merck Index, 14th ed., ed. M. J. O’Neil, Wiley, 2006. A useful one-volume work containing ten thousand brief monographs on drugs and simple laboratory chemicals. Includes

Organic Chemist's Desk Reference, Second Edition

a CD-ROM; also available online through, among others, Dialog at www.library.dialog.
com/bluesheets and Cambridgesoft at http://the merckindex.cambridgesoft.com.
Methods in Enzymology, Elsevier, 1955–. An ongoing series with over three hundred volumes, each devoted to a specific topic in biochemistry. Earlier volumes contain useful
properties/procedures for small molecules of biochemical interest.
Natural Product Reports, Royal Society of Chemistry. 1984–. Review series with timely
updates on different classes of natural products, though the coverage depends on the availability of a suitable specialist reviewer at any one time. Each issue starts with a very useful
current awareness section, “Hot off the Press.”
Organic Reactions, Wiley, 1942–. Contains review chapters, each devoted to a single reaction
of wide applicability. Vol. 70, ed. L. E. Overman, published in 2008.
Organic Syntheses, 1921–. Formerly published by Wiley but now independent under the editorial board (Organic Syntheses, Inc.). Series giving checked and edited procedures for
particular compounds or groups of compounds of interest. Collective volumes were issued
containing revised versions of annual parts. Available free at www.orgsyn.org. Articles
from recent volumes that have not yet been incorporated in the searchable database can be
seen at Org.Syn Express.
The Pesticide Manual, 15th ed., British Crop Protection Council, 2009. One-volume publication containing monographs on several hundred pesticides and agrochemicals, current and
obsolete. Also available as a CD-ROM.
Progress in the Chemistry of Organic Natural Products (formerly Fortschritte der Chemie
Organisher Naturstoffe) (“Zechmeister”), Springer, 1938–. Review series on various classes
of natural products, with one or more topics covered in each volume. Had reached vol. 89
by 2008.
Progress in Heterocyclic Chemistry. Elsevier. Review series. Vol. 19, ed. G. W. Gribble and
J. A. Joule, published in 2008, consists of a critical review of the 2006 literature preceded
by two chapters on current heterocyclic topics. Individual chapters can be purchased as
PDF files.
Rodds’s Chemistry of Carbon Compounds, 2nd ed., ed. S. Coffey, 1964–1989. Supplementary
volumes, ed. M. F. Ansell, 1973–1990; 2nd supplement, ed. M. Sainsbury, Elsevier,
1991–2002. A monograph covering the whole of organic chemistry in five volumes plus
supplements: Vol. I, aliphatic compounds; II, alicyclic compounds; III, aromatic compounds; IV, heterocyclic compounds; and V, indexes and miscellaneous update volumes
(e.g., Electrochemistry, 2002). A good source for getting a rapid overview of an unfamiliar
class of compounds, for example, but now showing its age. There is a cumulative index to
the whole second edition and supplements. It is available online at ScienceDirect.com. It is
not known if a new edition is planned.
Science of Synthesis, multi-authored, Thieme Verlag. The subscription electronic version of
Houben-Weyl, originally an exhaustive multivolume German language encyclopedia of
synthetic methods. The printed version eventually contained 146,000 procedures, 580,000
structures, and 700,000 references. SoS retains the readable-text format of the original,
with extensive HTML and structure markup for searchability. The current version (3.6)
consists of 38 volumes and 215,000 reactions (www.science-of-synthesis.com).
Specialist Periodical Reports, RSC. A series of one-volume updates on developments in
particular areas of research. Approximately ten titles remain current. The more popular
appear annually; other titles are sporadic or discontinued. Those of most interest to organic
chemists are Amino Acids, Peptides and Proteins (Vol. 36, literature coverage to 2003,
published 2007), Carbohydrates (Vol. 34, literature coverage to 2002, published 2003),
and Organophosphorus Chemistry (Vol. 37, literature coverage to 2007, published 2008).

The Organic Chemistry Literature

Other titles cover NMR, catalysis, etc. Some chapters are available on free access, but the
majority are on a payment basis by licence agreement.
Theilheimer’s Synthetic Methods of Organic Chemistry, Karger, 1948–. Most recent: Vol. 72,
ed. G. Tozer-Hotchkiss, 2008. Another large synthetic methods compendium, less electronically available than Science of Synthesis, although the latest volumes have an ActiveBook
electronic search facility.

1.4 Patents, Including Patent Awareness Services
Terry Ward
A patent is an exclusive right granted by a state to an inventor or its assignee to make use of an
invention or process for a fixed period of time in exchange for its public disclosure. Formerly the
terms under which patents were granted varied considerably between countries, but in recent years
attempts have been made to standardise international rules, and all technology patents (including
chemical patents) by members of the World Trade Organisation (WTO) are now granted for a period
of twenty years from the date of filing.
Each country issues its own patents valid only in that country, so the same invention is usually
patented in several countries. These patent duplications are known as equivalents. Equivalents may
be filed in different languages, which can be useful if the original is in a language unfamiliar to the
researcher. Abstracting services will generally abstract the first published application with a crossindex to their equivalents in other countries.
Before a patent is granted, the patent application is examined by the relevant national patent
office for novelty, invention, and utility. Since this process is lengthy, most authorities publish the
unexamined application eighteen months after the patent is filed. Although information present in
patents may subsequently be reported in the open literature, the original patent application will
always be the earliest publication of its chemical content. These are of particular interest to organic
chemists because of the large number of newly synthesised compounds that are reported particularly by the pharmaceutical and agrochemical industries.
Apart from applications to national authorities, patent applications may also be made through
the European Patent Office (EPO) and the International Bureau of the World Intellectual Property
Organisation (WIPO) under the Patent Cooperation Treaty (PCT).
The EPO was set up by the European Patent Convention of 1973, and its first patents were granted
in 1980. At the end of 2008, contracting states to the EPO comprised the twenty-seven member
states of the European Union plus Croatia, Iceland, Liechtenstein, Monaco, Norway, Switzerland,
Turkey, and Macedonia. The EPO grants patents in whichever of these countries are designated on
the specification, and the patent documents are published in English, French, or German.
The PCT came into force in 1978 and by November of 2008 provided for filing in 139 countries.
Submission of a PCT application to a single patent office of a PCT contracting state automatically
designates all other member states. A centralised novelty search report is then passed on to member
states, each of which decide whether to grant a patent. The WIPO does not grant the patents. The
PCT applications themselves are published eighteen months after filing in one of eight languages,
at present (end of 2008) Arabic, Chinese, English, French, German, Japanese, Russian, or Spanish.
An abstract is published in English.

1.4.1 Markush Structures
Chemical patents often contain Markush structures, named after Eugene Markush, who was the
first inventor to win a claim allowing such structures in 1925. These generic structures allow large
numbers of compounds to be claimed even though few of these will actually have been synthesised.

Organic Chemist's Desk Reference, Second Edition

An example is shown below where X, Y, Z, and R can refer to a wide range of atoms or chemical
groups specified by the inventor.
X
N
R1

Y
N
Z

Markush Structure

1.4.2 Patent Numbering
When searching for patents a basic understanding of patent documentation and numbering systems
is helpful. Published patent documents comprise two types: patent applications and granted patents.
It is important to note that these two documents may have different serial numbers. A patent application is the initial document submitted to a patent office describing the invention. This application
will be subject to examination by the patent office for compliance with relevant patent laws and
may or may not lead to a granted patent. Published applications and granted patents are assigned a
unique publication number comprising a two-letter country code (see http://www.wipo.org/ for a full
list) followed by a serial number of up to twelve digits (varies with country) followed by a type code
comprising a letter, usually A, B, or C. These type codes distinguish between different publication
stages of the same patent and originally corresponded to the unexamined application, examined
application, or granted patent documents, respectively. However, over the years considerable variation has developed between different jurisdictions in their use. For example, the EPO only publishes
at two stages: A for applications and B for granted patents. Again, prior to 2001, U.S. patents were
only published as the granted A patent, but since January 2001, they follow the same two-stage
publication and A, B designation as the EPO. These letter codes may also be followed by a numerical suffix indicating the number of times the specification has been published with modifications,
e.g., A1 (patent application with search report) or A2 (patent application without search report), etc.
A full list of type codes used by CAS may be found at http://www.cas.org/expertise/cascontent/
caplus/patcoverage/patkind.html. In the case of patent applications, but not granted patents, the
serial number may begin with a year code. These year codes may vary with time, leading to some
confusion. For example, PCT applications from 1978 to the end of 2003 begin with the last two
digits of the Western year; however, from the beginning of 2004 PCT applications begin with all
four-year digits. Postmillennium Japanese application numbers also begin with a four-digit Western
year code, but prior to the millennium the year code corresponded to the year of the Japanese
emperor’s reign (Yoen year). The present emperor, Akihito, ascended the throne in 1989, which is
year 1 of the current cycle (Heisei period). Therefore, the Heisei year equals the last two numbers
of the Western year minus 88. The previous emperor, Hirohito, reigned from 1926 to 1989 (Showa
period). Accordingly, the Showa year equals the last two numbers of the Western year minus 25.
Obviously, there is an overlapping period in 1989 at the interregnum. Heisei and Showa periods are
often abbreviated as H and S. Some examples of patent number formats are given below:
WO2005021545 A1 (2005 PCT application with four-digit year code)
WO9640757 A2 (1996 PCT application with two-digit year code)
US5096901 A (U.S. granted patent, issued prior to 2001, no year code)
US7189852 B2 (U.S. granted patent issued after January 1, 2001, with pregrant publication,
no year code; note, if no pregrant publication, then B1)
US20050054561 A1 (2005 U.S. patent application with four-digit year code)
JP5019556 B1 (1993 Japanese examined application, Yoen year 5)

The Organic Chemistry Literature

1.4.3 Patent Awareness Services
Since patents are not normally held in research libraries, most researchers obtain their initial information on patents from abstracting services. The foremost of these, Chemical Abstracts (CA), has
covered chemical, biochemical, and chemical engineering patents from 1907 to the present. CAS
abstracts over one hundred thousand patents annually from fifty-seven patent authorities. These
abstracts are based on the earliest published patent or patent application, and where an invention is
patented in more than one country, the equivalent patents are cross-referenced. In the print version
this is done through the Patent Indexes, but for the electronic versions equivalent patents are listed
in one entry based on a common priority date. Cross-indexing allows an equivalent patent in an
alternative language to be identified if required. Only real chemical substances are indexed by CA;
virtual compounds exemplified only within a generic Markush structure are not indexed. However,
Markush structures can be searched on the CAS Markush database (MARPAT) containing more
than 750,000 Markush structures from patents covered by CAS from 1961 to present.
Most patents are now available free online from one or more patent authorities. The most useful
of these are the EPO, U.S., and Japanese patent office sites.
The EPO esp@cenet (ep.espacenet.com) database contains more than 60 million patents from
85 countries worldwide (not just European Convention countries). The database is searchable by
application number, assignee, inventor, or keywords from the title or abstract. Chemical structure
searches are not possible. Patents can be viewed as images of the original document in PDF format
one page at a time, or the whole patent can be viewed as a text document. Instantaneous translation
from French or German into English is available for the latter document type if required. Equivalent
published patents, if any, are also listed and are available in PDF format. The text documents do not
show chemical structures or diagrams, but these can be viewed in PDF format if required.
The U.S. Patent and Trade Mark Office (USPTO) database (http://patft.uspto.gov/) provides
access to granted U.S. patents from 1976 and patent applications from March 2001. Patents can
be viewed as text documents (without structures or diagrams) or as single-page images of the
original document in TIFF format. Patents prior to 1976 and back to 1790 are available as TIFF
images only.
The Industrial Property Digital Library of the Japanese Patent Office (JPO’s IPDL; http://www.
ipdl.inpit.go.jp/homepg_e.ipdl) provides access to Japanese patent document in Japanese text.
However, for non-Japanese readers, instantaneous machine translations from Japanese to English
of the full documents are available over the Internet from 1974 onwards. English abstracts are also
available for recent patents.
Free patent information is provided by the website http://www.freepatentsonline.com/, covering
U.S., EP, and PCT patents/applications and Japanese patent abstracts. In addition to the usual textbased searches in various search fields, this site also enables graphically input chemical structure
searches to be performed on over 9 million compounds (including prophetic compounds) using
exact structure, substructure, or chemical similarity searches. Chemistry searches using SMILES
strings or chemical names are also possible. Full patent documents may be viewed in text or
PDF format.
Chemical patent abstracts can be found in the Chemical Patent Index (published by Thompson
Scientific). This is derived from the Derwent World Patent Index and provides abstracts of chemical patents from at least thirty-nine countries, including the EPO and PCT, and is updated weekly.
All chemical patents are covered from 1970 to date, with additional coverage of pharmaceutical
patents from 1963, agricultural patents from 1965, and polymers from 1966. Searching is based on
the full patent specification, not just the abstract. In addition to text searching, the use of Derwent’s
structural fragment codes allows structure searching on both specifically disclosed compounds and
Markush structures. Polymers may also be searched using structural polymer codes.

Organic Chemist's Desk Reference, Second Edition

1.5 Cheminformatics Companies
The development of algorithms for the handling of chemical structures and data, and the application
of artificial intelligence to property prediction, etc., led to the emergence of companies specialising in chemical software applications, now known as chem(o)informatics. Ideally such enterprises
should couple with large dictionary databases.
The pioneer in this area was Molecular Design, later MDL Systems, which after a period of
ownership by Elsevier was acquired by Symyx in 2007. The company now serves drug design R&D
within the corporate client sector.
Symyx also runs the Available Chemicals Directory, launched originally by ACD Labs as a
merged database of chemical supplier catalogues with structure search capability. The database
provides access to over 1 million commercially available chemical compounds. The original concept has been extensively developed with the addition of other freely available software packages.
ChemAxon (www.chemaxon.com/marvin) provides services such as MarvinSketch (structure
and reaction query editor), MarvinSpace (3D structure visualisation), and several others.
ChemSpider was launched in 2007. It is an open-access service in which constituent databases,
the largest of which is Web of Science, are linked on a free-access basis, and which uses algorithms
to identify and extract chemical names from documents and web pages and convert them to structures and InChI and SMILES identifiers. Access to the core service is free, but the user may be
routed to charging component databases. At launch, ChemSpider contained 21 million compounds.
At the time of writing, it was too early to assess the success of the service. It was bought by the
Royal Society of Chemistry in 2009.
Registration is free at www.chemspider.com. For a description of ChemSpider, see Williams, A.,
Chemistry International, 30 (1), 2008, available online at www.iupac.org/publications.

2 Primary Journals
This chapter gives details of the principal journals in organic chemistry plus some of the more
important journals in other areas of chemistry and biochemistry that may contain important information on organic chemistry. The following items of information are given:
• Full journal title.
• CASSI abbreviated title. CASSI (the Chemical Abstracts Service Source Index) includes
details on all journals cited in Chemical Abstracts since 1907, together with some cited in
Beilstein and Chemisches Zentralblatt back to 1830. CASSI gives an abbreviated title for
each journal, and these are widely used and recognised.1
• Years of publication.
• A statement, if applicable, that a journal does not have volume numbers, together with
details of when volume numbers were introduced or discontinued. Volume numbers are
given for some of the longer-established journals that have seen several changes of title.
• Some indication of subject matter where it is not obvious from the title, or where a journal
is published in two or more parts.
• Changes of journal and superseded titles.
• Translation journals.
• Name of the publisher of the current title (2009) and online (web) archive, or of the publisher of the online (web) archive for a former title.2
• Information on free online access to the full text of chemistry journals on the web (as of
2009).3
Accounts of Chemical Research [Acc. Chem. Res.] (1968–). Review journal. Publisher: ACS.
Acta Chemica Scandinavica [Acta Chem. Scand.] (1947–1973, 1989–1999). From 1974–1988
(Vols. 29–42) divided into Series A [Acta Chem. Scand., Ser. A] (physical and inorganic
chemistry) and Series B [Acta Chem. Scand., Ser. B] (organic chemistry and biochemistry). In 1999, absorbed in part by Journal of the Chemical Society, Dalton Transactions,
Journal of the Chemical Society, Perkin Transactions 1, and Journal of the Chemical
Society, Perkin Transactions 2. See Journal of the Chemical Society. Free online full-text
archive at http://actachemscand.dk/.
Acta Chimica Sinica. See Chinese Journal of Chemistry and Huaxue Xuebao.
Acta Chimica Slovenica [Acta Chim. Slov.] (1993–). Formerly Vestnik Slovenskega
Kemijskega Drustva [Vestn. Slov. Kem. Drus.] (1954–1992). Free online full-text archive
from 1998. Publisher: Slovenian Chemical Society.
Acta Crystallographica [Acta Crystallogr.] (1948–1967). In 1968, divided into Section A
[Acta Crystallogr., Sect. A] (1968–) (current subtitle: foundations of crystallography) and
SecÂ�tion B [Acta Crystallogr., Sect. B] (1968–) (current subtitle: structural science). Later
sections added are Section C [Acta Crystallogr., Sect. C] (1983–) (crystal structure communications), formerly Crystal Structure Communications [Cryst. Struct. Commun.] (1972–82);
Section D [Acta Crystallogr., Sect. D] (1993–) (biological crystallography); Section E [Acta
Crystallogr., Sect. E] (2001–) (structure reports online); and Section F [Acta Crystallogr.,
Sect. F] (2005–) (structural biology and crystallisation communications). (Additional CASSI
abbreviated subtitles are omitted.) Some online free access to recent archives for Sections
A–F. Publisher: International Union of Crystallography. http://journals.iucr.org/.
23

Organic Chemist's Desk Reference, Second Edition

Acta Pharmaceutica [Acta Pharm. (Zagreb, Croatia)] (1992–). Formerly Acta Pharmaceutica
Jugoslavia [Acta Pharm. Jugosl.] (1951–91). Publisher: Croatian Pharmaceutical Society.
Acta Pharmaceutica Fennica. See European Journal of Pharmaceutical Sciences.
Acta Pharmaceutica Nordica. See European Journal of Pharmaceutical Sciences.
Acta Pharmaceutica Suecica. See European Journal of Pharmaceutical Sciences.
Advanced Synthesis & Catalysis [Adv. Synth. Catal.] (Vol. 343–, 2001–). Formerly Journal
für Praktische Chemie [J. Prakt. Chem.] (Vols. 1–270, 1834–1943; Vols. 273–333, 1954–
1991; Vols. 341–342, 1999–2000) and Journal für Praktische Chemie—Chemiker-Zeitung
[J. Prakt. Chem./Chem. Ztg.] (Vols. 334–340, 1992–1998) (following a merger with ChemikerZeitung [Chem.-Ztg.] (1879–1991)). Between 1943 and 1944, the journal was briefly titled
Journal für Makromolekulare Chemie [J. Makromol. Chem.] (Vols. 271–272, 1943–1944).
Alternative volume numbers are also used: Vols. 109–270 (1870–1943) are numbered Vols.
1–162 (the second series); Vols. 271–272 (1943–1944) are numbered Vols. 1–2 (the third
series); and Vols. 273–310 (1954–1968) are numbered Vols. 1–38 (the fourth series). Free
online full-text archive 1870–1938 from Gallica (Bibliothèque nationale de France): http://
gallica.bnf.fr/. Publisher (current title and online archive from 1834): Wiley.
Agricultural and Biological Chemistry. See Bioscience, Biotechnology, and Biochemistry.
Aldrichimica Acta [Aldrichim. Acta] (1968–). Free online full-text archive. Publisher:
Sigma-Aldrich.
American Chemical Journal. See Journal of the American Chemical Society.
Anales de Quimica [An. Quim.] (1968–1979, 1990–1995). From 1980 to 1989, divided into
Series A [An. Quim., Ser. A] (physical and technical), Series B [An. Quim., Ser. B] (inorganic
and analytical), and Series C [An. Quim., Ser. C] (organic and biochemical). Became Anales
de Quimica International Edition [An. Quim. Int. Ed.] (1996–1998). No longer published.
Angewandte Chemie [Angew. Chem.] (1988–). From 1888 to 1941, the title was Zeitschrift
fur Angewandte Chemie [Z. Angew. Chem.]. In German, but in 1962 an International
Edition in English [Angew. Chem., Int. Ed. Engl.] (1962–) was launched, which in 1998
became Angewandte Chemie, International Edition [Angew. Chem., Int. Ed.] (1998–). The
German and English editions have different volume and page numbers. Vol. 1 of the international edition corresponds to Vol. 74 of the German edition. In 1982 and 1983, miniprint
supplements were issued. In 1991, Angewandte Chemie absorbed Zeitschrift für Chemie
[Z. Chem.] (1961–90). Publisher: Wiley.
Annalen. See Liebigs Annalen.
Annalen der Chemie und Pharmazie. See Liebigs Annalen.
Annales de Chimie [Ann. Chim. (Cachan, Fr.)] (2004–). Previous CASSI abbreviation
Ann. Chim. (Paris) (1789–1815, 1914–2003). From 1816 to 1913, the title was Annales de
Chimie et de Physique [Ann. Chim. Phys.]. There have been various series of volume numbers; the fifteenth series, Vol. 1 appeared in 1976. From 1978 (Vol. 3) series designations
ceased. Since 1973 this journal has specialised in solid-state chemistry; in 1978 Science
de Matériaux became a subtitle. Free online full-text archive 1841–1913 from Gallica
(Bibliothèque nationale de France): http://gallica.bnf.fr/. Publisher: Lavoisier.
Annales Pharmaceutiques Français [Ann. Pharm. Fr.] (1943–). Formed by a merger of
Journal de Pharmacie et de Chemie [J. Pharm. Chim.] (1842–1942) and Bulletin des
Sciences Pharmacologiques [Bull. Sci. Pharmacol] (1899–1942). Free online full-text
archive 1842–1894 from Gallica (Bibliothèque nationale de France): http://gallica.bnf.fr/.
Publisher: Elsevier.
Annali di Chimica [Ann. Chim. (Rome)] (1950–2007). Formerly Annali di Chimica
Applicata [Ann. Chim. Appl.] (1914–1918, 1924–1949). Superseded by ChemSusChem
[ChemSusChem] (2008–). Online archive publisher (2004–2007): Wiley.
Annals of the New York Academy of Science [Ann. N.Y. Acad. Sci.] (1877–). Irregular. No
issue numbers. Publishers: The New York Academy of Sciences and Wiley.

Primary Journals

Antibiotiki i Khimioterapiya [Antibiot. Khimioter.] (1988–). Formerly Antibiotiki [Antibiotiki
(Moscow)] (1956–1984) and Antibiotiki i Meditsinskaya Bioteknologiya [Antibiot. Med.
Biotekhnol.] (1985–1987). Publisher: Media Sphera, Moscow.
Applied Organometallic Chemistry [Appl. Organomet. Chem.] (1987–). Publisher: Wiley.
Archiv der Pharmazie [Arch. Pharm. (Weinheim, Ger.)] (1835–). From 1924–1971 known as
Archiv der Pharmazie und Berichte der Deutschen Pharmazeutischen Gesellschaft [Arch.
Pharm. Ber. Dtsch. Pharm. Ges.]. Publisher: Wiley.
Archives of Biochemistry and Biophysics [Arch. Biochem. Biophys.] (1951–). Formerly
Archives of Biochemistry [Arch. Biochem.] (1942–1951). Publisher: Elsevier.
Arhiv za Kemiju. See Croatica Chemica Acta.
Arkiv foer Kemi. See Chemica Scripta.
ARKIVOC [ARKIVOC] (2000–). Electronic journal. Open access. Free online full-text
archive from 2000. Publisher: ARKAT USA, Inc.
Arzneimittel-Forschung [Arzneim.-Forsch.] (1951–). Drug research. Publisher: Editio Cantor
Verlag, Aulendorf, Germany
Asian Journal of Chemistry [Asian J. Chem.] (1989–). Absorbed Asian Journal of Chemistry
Reviews [Asian. J. Chem. Rev.] (1990–95). Publisher: Asian Journal of Chemistry, Sahibabad,
Ghaziabad, Uttar Pradesh, India.
Australian Journal of Chemistry [Aust. J. Chem.] (1953–). Superseded Australian Journal
of Scientific Research, Series A [Aust. J. Sci. Res., Ser. A] (1948–52). Publisher: CSIRO
Publishing.
Beilstein Journal of Organic Chemistry [Beilstein J. Org. Chem.] (2005–). Electronic journal. Open access. Free online full-text archive from 2005. Publisher: Beilstein-Institut,
Frankfurt am Main, Germany.
Berichte. See Chemische Berichte.
Berichte der Bunsen-Gesellschaft [Ber. Bunsen-Ges.] (1963–1998). Formerly Zeitschrift
für Elektrochemie und Angewandte Physikalische Chemie [Z. Elektrochem. Angew. Phys.
Chem.] (1894–1951) (publication suspended 1945 to 1947) and Zeitschrift für Elektrochemie
[Z. Elektrochem.] (1951–1962). Merged with Journal of the Chemical Society, Faraday
Transactions to form Physical Chemistry Chemical Physics.
Berichte der Deutschen Chemischen Gesellschaft. See Chemische Berichte.
Biochemical and Biophysical Research Communications [Biochem. Biophys. Res.
Commun.] (1959–). Publisher: Elsevier.
Biochemical Journal [Biochem. J.] (1906–). From 1973 to 1983, alternate issues subtitled
Molecular Aspects and Cellular Aspects. Free online full-text archive. Publisher: Portland
Press Ltd. Essex.
Biochemical Society Transactions [Biochem. Soc. Trans.] (1973–). Replaced a proceedings
section formerly included in Biochemical Journal. Publisher: Portland Press Ltd., Essex.
Biochemical Systematics and Ecology [Biochem. Syst. Ecol.] (1974–). Formerly Biochemical
Systematics [Biochem. Syst.] (1973). Publisher: Elsevier.
Biochemistry [Biochemistry] (1962–). Publisher: ACS.
Biochimica et Biophysica Acta [Biochim. Biophys. Acta] (1947–). Issued in different sections. Publisher: Elsevier.
Biochimie [Biochimie] (1971–). Formerly Bulletin de la Société de Chimie Biologique [Bull.
Soc. Chim. Biol.] (1914–70). Publisher: Elsevier.
Biological and Pharmaceutical Bulletin. See Chemical and Pharmaceutical Bulletin.
Biological Chemistry [Biol. Chem.] (Vol. 377, 1996–). Superseded Biological Chemistry
Hoppe-Seyler [Biol. Chem. Hoppe-Seyler] (Vols. 366–377, 1985–1996). Formerly
Zeitschrift für Physiologische Chemie [Z. Physiol. Chem.] (1877–1895) and Hoppe-Seyler’s
Zeitschrift für Physiologische Chemie [Hoppe-Seyler’s Z. Physiol. Chem.] (1895–1984).
Publisher: Walter de Gruyter, New York and Berlin.

Organic Chemist's Desk Reference, Second Edition

Biological Mass Spectrometry. See Journal of Mass Spectrometry.
Biomedical and Environmental Mass Spectrometry. See Journal of Mass Spectrometry.
Biomedical Mass Spectrometry. See Journal of Mass Spectrometry.
Bioorganic and Medicinal Chemistry [Bioorg. Med. Chem.] (1993–). Publisher: Elsevier.
Bioorganic and Medicinal Chemistry Letters [Bioorg. Med. Chem. Lett.] (1991–).
Publisher: Elsevier.
Bioorganic Chemistry [Bioorg. Chem.] (1971–). Publisher: Elsevier.
Bioorganicheskaya Khimiya [Bioorg. Khim.] (1975–). In Russian. Bioorganicheskaia
Khimiya is an alternative spelling. There is an English language translation called Russian
Journal of Bioorganic Chemistry [Russ. J. Bioorg. Chem.] (1993–). Formerly Soviet
Journal of Bioorganic Chemistry [Sov. J. Bioorg. Chem. (Engl. Transl.)] (1975–1992).
Publisher: Springer/MAIK Nauka/Interperiodica.
Bioscience, Biotechnology, and Biochemistry [Biosci., Biotechnol., Biochem.] (Vol. 56–,
1992–). Formerly Bulletin of the Agricultural Chemical Society of Japan [Bull. Agric.
Chem. Soc. Jpn.] (1924–1960) and Agricultural and Biological Chemistry [Agric. Biol.
Chem.] (1961–1991). Free online full-text archive. Publisher: Japan Society for Bioscience,
Biotechnology and Agrochemistry.
Bulletin de la Société de Chimie Biologique. See Biochimie.
Bulletin de la Société Chimique de France [Bull. Soc. Chim. Fr.] (1858–1997). Five series of
volume numbers were assigned between 1858 and 1954. No volume numbers issued from
1955 to 1991; 1992 is Vol. 129; 1997 is Vol. 134. From 1933 to 1945, published as Bulletin
de la Société Chimique de France, Documentation (abstracts, obituaries, etc.) and Bulletin
de la Société Chimique de France, Memoires (research papers). From 1978 to 1984, each
issue was split into two parts (la première partie: chimie analytique, minérale et physicochimie; la deuxième partie: chimie moléculaire). In order to distinguish the two parts for
these years, the page number is prefixed by the part number, e.g., Es-Seddiki, S., et al.,
Bull. Soc. Chim. Fr., 1984, II-241. No longer published. Superseded by European Journal
of Inorganic Chemistry and European Journal of Organic Chemistry.
Bulletin des Sciences Pharmacologiques. See Annales Pharmaceutiques Français.
Bulletin des Sociétés Chimiques Belges [Bull. Soc. Chim. Belg.] (1904–1997). Formerly
Bulletin de l’Association Belge des Chimistes (1887–1903). No longer published. Superseded
by European Journal of Inorganic Chemistry and European Journal of Organic Chemistry.
Bulletin of the Academy of Sciences of the USSR, Division of Chemical Sciences. See
Izvestiya Akademii Nauk, Seriya Khimicheskaya.
Bulletin of the Chemical Society of Japan [Bull. Chem. Soc. Jpn.] (1926–). Free online fulltext archive. Publisher: The Chemical Society of Japan.
Bulletin of the Korean Chemical Society [Bull. Korean Chem. Soc.] (1980–). Free online
full-text archive from 1980. Publisher: Korean Chemical Society.
Bulletin of the Polish Academy of Sciences, Chemistry [Bull. Pol. Acad. Sci., Chem.]
(1983–). Formerly Bulletin de l’Academie Polonaise des Sciences, Serie des Sciences
Chimiques [Bull. Acad. Pol. Sci., Ser. Sci. Chim.] (1960–1982). Publisher: Polish Academy
of Sciences, Warsaw.
Bulletin of the Research Council of Israel. See Israel Journal of Chemistry.
Canadian Journal of Chemistry [Can. J. Chem.] (1951–). Continuation of Canadian Journal
of Research [Can. J. Res.] (1929–1935) and its subsequent Section B [Can. J. Res., Sect. B]
(1935–1950) (chemical sciences). Free online full-text archive 1951–1997. Publisher: NRC
Research Press.
Carbohydrate Letters [Carbohydr. Lett.] (1994–2001). No longer published.
Carbohydrate Polymers [Carbohydr. Polym.] (1981–). Publisher: Elsevier.
Carbohydrate Research [Carbohydr. Res.] (1965–). Publisher: Elsevier.

Primary Journals

Cellular and Molecular Life Sciences [Cell. Mol. Life Sci.] (1997–). Formerly Experientia
[Experientia] (1945–1996). Publisher: Springer.
Central European Journal of Chemistry [Cent. Eur. J. Chem.] (2003–). Publisher: Versita,
Warsaw, Poland, and Springer.
ChemBioChem [ChemBioChem] (2000–). Publisher: Wiley.
Chemica Scripta [Chem. Scr.] (1971–1989). Successor to Arkiv foer Kemi [Ark. Kemi]
(1949–1971). No longer published.
Chemical Biology & Drug Design [Chem. Biol. Drug Des.] (2006–). Formerly Journal of
Peptide Research. Publisher: Wiley.
Chemical & Pharmaceutical Bulletin [Chem. Pharm. Bull.] (1958–). Formerly PharmaÂ�
ceutical Bulletin [Pharm. Bull.] (1953–1957). In 1993 biologically oriented papers were
transferred to Biological & Pharmaceutical Bulletin [Biol. Pharm. Bull.] (1993–). Free
online full-text archive. Publisher: The Pharmaceutical Society of Japan.
Chemical Communications (Cambridge) [Chem. Commun. (Cambridge)] (1996–). Formerly
Chemical Communications [Chem. Commun.] (1965–1968); Journal of the Chemical
Society [Part] D [J. Chem. Soc. D] (1969–1971); and Journal of the Chemical Society,
Chemical Communications [J. Chem. Soc., Chem. Commun.] (1972–1995). No volume
numbers. See also Journal of the Chemical Society and Proceedings of the Chemical
Society, London. Publisher: RSC.
Chemical Papers [Chem. Pap.] (1985–). Formerly Chemické Zvesti [Chem. Zvesti]
(1947–1984). Publisher: Versita, Warsaw, Poland, and Springer.
Chemical Record [Chem. Rec.] (2001–). A review journal. Publisher: Wiley.
Chemical Reviews [Chem. Rev.] (1924–). Publisher: ACS.
Chemical Society Reviews [Chem. Soc. Rev.] (1972–). Successor to Quarterly Reviews of
the Chemical Society [Q. Rev., Chem. Soc.] (1947–1971) and RIC Reviews [RIC Rev.]
(1968–1971). Publisher: RSC.
Chemické Listy [Chem. Listy] (1951–). Formerly Chemické Listy pro Vedu a Prumysl [Chem.
Listy Vedu Prum.] (1907–1950). Publisher: Czech Chemical Society.
Chemické Zvesti. See Chemical Papers.
Chemiker-Zeitung. See Advanced Synthesis & Catalysis.
Chemische Berichte [Chem. Ber] (1947–96). Formerly Berichte der Deutschen Chemischen
Gesellschaft [Ber. Dtsch. Chem. Ges.] (1868–1945), which from 1919 to 1945 was divided into
Abteilung A [Ber. Dtsch. Chem. Ges. A] (Vereinsnachrichten) and Abteilung B [Ber. Dtsch.
Chem. Ges. B] (Abhandlungen). Early volumes are often cited colloquially as Berichte. In
1997, merged with Recueil des Travaux Chimiques des Pays-Bas to form Chemische Berichte/
Recueil [Chem. Ber./Recl.] (1997). No longer published. In 1998, superseded by European
Journal of Inorganic Chemistry. Free online full-text archive 1868–1901 from Gallica
(Bibliothèque nationale de France): http://gallica.bnf.fr/. Online archive publisher: Wiley.
Chemische Berichte/Recueil. See Chemische Berichte.
Chemistry—An Asian Journal [Chem.—Asian J.] (2006–). Publisher: Wiley.
Chemistry—A European Journal [Chem.—Eur. J.] (1995–). Publisher: Wiley.
Chemistry & Biodiversity [Chem. Biodiversity] (2004–). Publisher: Verlag Helvetica Chimica
Acta AG, Zürich/Wiley.
Chemistry & Industry [Chem. Ind. (London)] (1923–). Formerly Journal of the Society of
Chemical Industry, London, Review Section [J. Soc. Chem. Ind., London, Rev. Sect.]
(1918–22). No volume numbers. Publisher: The Society of Chemical Industry.
Chemistry and Physics of Lipids [Chem. Phys. Lipids] (1966–). Publisher: Elsevier.
Chemistry Express [Chem. Express] (1986–1993) (Journal of Kinki Chemical Society,
Japan). No longer published.

Organic Chemist's Desk Reference, Second Edition

Chemistry Letters [Chem. Lett.] (1972–). No volume numbers. Some free online full-text
issues from 2002. Publisher: The Chemical Society of Japan.
Chemistry of Heterocyclic Compounds. See Khimiya Geterotsiklicheskikh Soedinenii.
Chemistry of Natural Compounds. See Khimiya Prirodnykh Soedinenii.
ChemMedChem [ChemMedChem] (2006–). See also Farmaco. Publisher: Wiley.
Chimia [Chimia] (1947–). No volume numbers. Publisher: Swiss Chemical Society.
Chimica Therapeutica. See European Journal of Medicinal Chemistry.
Chinese Chemical Letters [Chin. Chem. Lett.] (1991–). Free online full-text archive
1999–2006. Publisher: Elsevier.
Chinese Journal of Chemistry [Chin. J. Chem.] (1990–). Formerly Acta Chimica Sinica
[Acta Chim. Sin. (Engl. Ed.)] (1983–1989). Chin. J. Chem. and Huaxue Xuebao are two
separate journals, and Chin. J. Chem. does not contain translations from Huaxue Xuebao.
Publisher: Shanghai Institute of Organic Chemistry (Chinese Academy of Sciences) and
Wiley-VCH on behalf of the Chinese Chemical Society.
Chirality [Chirality] (1989–). Publisher: Wiley.
Collection of Czechoslovak Chemical Communications [Collect. Czech. Chem. Commun.]
(1929–). Publisher: Institute of Organic Chemistry and Biochemistry, Czech Republic.
Comptes Rendus Chimie [C. R. Chim.] (Vol. 5, 2002–). See also Comptes Rendus
Hebdomadaires des Seances de l’Academie des Sciences. Publisher: French Academy of
Sciences/Elsevier.
Comptes Rendus Hebdomadaires des Seances de l’Academie des Sciences [C. R. Hebd.
Seances Acad. Sci.] (Vols. 1–261, 1835–1965). In 1966, divided into Series A: Comptes
Rendus des Seances de l’Academie des Sciences, Serie A [C. R. Seances Acad. Sci., Ser. A]
(Vols. 262–291, 1966–1980) (mathematical sciences); Series B [C. R. Seances Acad. Sci.,
Ser. B] (Vols. 262–291, 1966–1980) (physical sciences); Series C [C. R. Seances Acad.
Sci., Ser. C] (Vols. 262–291, 1966–1980) (chemical sciences); and Series D [C. R. Seances
Acad. Sci., Ser. D] (Vols. 262–291, 1966–1980) (life sciences). Series B–D were superseded by Series 2 [C. R. Seances Acad. Sci., Ser. 2] (physics, chemistry, astronomy, earth,
and planetary sciences; formerly Series B + C) (Vols. 292–297, 1981–1983) and Series
3 [C. R. Seances Acad. Sci., Ser. 3] (life sciences; formerly series D) (Vols. 292–297.
1981–1983). Series 2 was superseded by Comptes Rendus de l’Academie des Sciences,
Serie II: Mecanique, Physique, Chimie, Sciences de la Terre et de l’Univers [C. R. Acad.
Sci., Ser. II: Mec., Phys., Chim., Sci. Terre Univers.] (Vols. 298–317, 1984–1993). Series II
was replaced, in part, by Series IIb [C. R. Acad. Sci., Ser. IIb: Mec., Phys., Chim., Astron.]
(Vols. 318–325, 1994–1997), and Series IIb was superseded, in part, by Series IIc [C. R.
Acad. Sci., Ser. IIc: Chim.] (Vols. 1–4, 1998–2001). Series IIc was replaced by Comptes
Rendus Chimie [C. R. Chim.] (Vol. 5–, 2002–). Free online full-text archive 1835–1965
from Gallica (Bibliothèque nationale de France): http://gallica.bnf.fr/. Publisher: French
Academy of Sciences/Elsevier.
Contemporary Organic Synthesis [Contemp. Org. Synth.] (1994–1997). Review journal. No
longer published. Online archive publisher: RSC.
Croatica Chemica Acta [Croat. Chem. Acta] (1956–). Formerly Arhiv za Kemiju [Arh. Kem.]
(1927–1955). Free online full-text issues from 1998. Publisher: Croatica Chemica Acta,
Zagreb, Croatia.
Crystal Structure Communications. See Acta Crystallographia.
Current Organic Chemistry [Curr. Org. Chem.] (1997–). Publisher: Bentham Science
Publishers Ltd.
Current Organic Synthesis [Curr. Org. Synth.] (2004–). Publisher: Bentham Science
Publishers Ltd.
Current Protein & Peptide Science [Curr. Protein Pept. Sci.] (2000–). Publisher: Bentham
Science Publishers Ltd.

Primary Journals

Dalton Transactions [Dalton Trans.] (2003–). No volume numbers. Formerly Journal of the
Chemical Society, Dalton Transactions [J. Chem. Soc., Dalton Trans.] (1972–2002). See
also Journal of the Chemical Society. Publisher: RSC.
Doklady Akademii Nauk [Dokl. Akad. Nauk] (1933–). In Russian. Until 1992, the title was
Doklady Akademii Nauk SSSR [Dokl. Akad. Nauk SSSR]. There is an English language
translation of the chemistry section called Doklady Chemistry [Dokl. Chem.] (1956–).
Publisher: Springer/MAIK Nauka/Interperiodica.
Egyptian Journal of Chemistry [Egypt. J. Chem.] (1958–). From 1960 to 1969, the title was
Journal of Chemistry of the United Arab Republic [J. Chem. U.A.R.]. From 1970 to 1971,
the title was United Arab Republic Journal of Chemistry [U.A.R. J. Chem.]. Publisher:
National Information and Documentation Centre, Cairo, Egypt.
European Journal of Inorganic Chemistry [Eur. J. Inorg. Chem.] (1998–). Formed by the
merger of Bulletin de la Société Chimique de France, Bulletin des Sociétés Chimique
Belges, Chemische Berichte/Recueil, and Gazzetta Chimica Italiana. No volume numbers.
Publisher: Wiley.
European Journal of Medicinal Chemistry [Eur. J. Med. Chem.] (1974–). Formerly Chimica
Therapeutica [Chim. Ther.] (1965–1973). Publisher: Elsevier.
European Journal of Organic Chemistry [Eur. J. Org. Chem.] (1998–). Formed by the
merger of Bulletin de la Société Chimique de France, Bulletin des Sociétés Chimique
Belges, Liebigs Annalen/Recueil, and Gazzetta Chimica Italiana. No volume numbers.
Publisher: Wiley.
European Journal of Pharmaceutical Sciences [Eur. J. Pharm. Sci.] (1993–). Formed by
a merger of Acta Pharmaceutica Fennica [Acta Pharm. Fenn.] (1977–1992) with Acta
Pharmaceutica Nordica [Acta Pharm. Nord.] (1989–1992). Acta Pharmaceutica Nordica
was formed by a merger of Acta Pharmaceutica Suecica [Acta Pharm. Suec.] (1964–1988)
and Norvegica Pharmaceutica Acta [Norv. Pharm. Acta] (1983–1986). Publisher: Elsevier.
Farmaco [Farmaco] (1989–2005) (Drugs). Incorporates Farmaco, Edizione Scientifica
[Farmaco, Ed. Sci.] (1953–1988) and Farmaco, Edizione Pratica [Farmaco, Ed. Prat.]
(1953–1988). No longer published. Replaced by ChemMedChem.
Finnish Chemical Letters [Finn. Chem. Lett.] (1974–1989). No longer published.
Fitoterapia [Fitoterapia] (1947–). The Journal for the Study of Medicinal Plants. Formerly
Estratti Fluidi Titolati. Publisher: Elsevier.
Gazzetta Chimica Italiana [Gazz. Chim. Ital.] (1871–1997). From 1891 to 1922, published in
two parts. No longer published. Superseded by European Journal of Inorganic Chemistry
and European Journal of Organic Chemistry.
Green Chemistry [Green Chem.] (1999–). Publisher: RSC.
Helvetica Chimica Acta [Helv. Chim. Acta] (1918–). Publisher: Verlag Helvetica Chimica
Acta AG, Zürich/Wiley.
Heteroatom Chemistry [Heteroat. Chem.] (1990–). Publisher: Wiley.
Heterocycles [Heterocycles] (1973–). Publisher: The Japan Institute of Heterocyclic
Chemistry/Elsevier.
Heterocyclic Communications [Heterocycl. Commun.] (1994–). Publisher: Freund Publishing
House Ltd., Tel Aviv, Israel.
Hoppe-Seylers Zeitschrift für Physiologische Chemie. See Biological Chemistry.
Huaxue Xuebao [Huaxue Xuebao] (Journal of Chemistry) (1953–; suspended 1966–1975). In
Chinese. Continues, in part, Journal of the Chinese Chemical Society (Peking) [J. Chin.
Chem. Soc. (Peking)] (1933–1952; suspended 1937–1939). Has been called Acta Chimica
Sinica (Chinese Edition) [Acta Chim. Sin. (Chin. Ed.)]. Until 1981, Chemical Abstracts
named Huaxue Xuebao as Hua Hsueh Hsueh Pao. Publisher: China International Book
Trading Corp., Beijing.

Organic Chemist's Desk Reference, Second Edition

Indian Journal of Chemistry [Indian J. Chem.] (1963–1975). In 1976, divided into Section
A [Indian J. Chem., Sect. A] (1976–) (inorganic, bioinorganic, physical, theoretical, and
analytical) and Section B [Indian J. Chem., Sect. B] (1976–) (organic and medicinal).
(Additional CASSI abbreviated subtitles omitted.) Indian Journal of Chemistry was a successor to Journal of Scientific and Industrial Research [J. Sci. Ind. Res.] (1942–1962),
which from 1946 to 1962 was divided into Section A [J. Sci. Ind. Res., Sect. A] (general),
Section B [J. Sci. Ind. Res., Sect. B] (physical sciences), and Section C [J. Sci. Ind. Res.,
Sect. C] (biological sciences). Free online full-text issues from 2007. Publisher: National
Institute of Science Communication and Information Resources, New Delhi, India.
Indian Journal of Heterocyclic Chemistry [Indian J. Heterocycl. Chem.] (1991–). Publisher:
Indian Journal of Heterocyclic Chemistry, Lucknow, India.
Inorganica Chimica Acta [Inorg. Chim. Acta] (1967–). Publisher: Elsevier.
Inorganic and Nuclear Chemical Letters. See Polyhedron.
Inorganic Chemistry [Inorg. Chem.] (1962–). Publisher: ACS.
Inorganic Chemistry Communications [Inorg. Chem. Commun.] (1998–). Publisher: Elsevier.
International Journal of Peptide and Protein Research [Int. J. Pept. Protein Res.] (1972–96).
Formerly International Journal of Protein Research [Int. J. Protein Res.] (1969–1971).
Merged with Peptide Research [Pept. Res.] (1988–1996) to form Journal of Peptide
Research. Online archive publisher: Wiley.
International Journal of Peptide Research and Therapeutics [Int. J. Pept. Res. Ther.]
(2005–). Formerly Letters in Peptide Science [Lett. Pept. Sci.] (1994–2003). (Not published in 2004.) Publisher: Springer.
International Journal of Sulfur Chemistry. See Phosphorus, Sulfur and Silicon and the
Related Elements.
Israel Journal of Chemistry [Isr. J. Chem.] (1963–). Successor to Bulletin of the Research
Council of Israel [Bull. Res. Counc. Isr.] (1951–1955) and its subsequent Section A
[Bull. Res. Counc. Isr., Sect. A] (1955–1963) (1955–1957, maths, physics, and chemistry;
1957–1963, chemistry). Publisher: Laser Pages Publishing Ltd., Jerusalem.
International Journal of Sulfur Chemistry. See Phosphorus, Sulfur and Silicon and the
Related Elements.
IUBMB Life [IUBMB Life] (1999–). Formerly Biochemistry International [Biochem. Int.]
(1980–) and Biochemistry and Molecular Biology International [Biochem. Mol. Biol. Int.]
(1993–1999). Publisher: Wiley.
Izvestiya Akademii Nauk, Seriya Khimicheskaya [Izv. Akad. Nauk, Ser Khim.] (1993–). In
Russian. Formerly Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya [Izv. Akad. Nauk
SSSR, Ser. Khim.] (1936–1992). Izvestiya Akademii Nauk SSSR, Otdelenie Khimicheskikh
Nauk [Izv. Akad. Nauk SSSR, Otd. Khim. Nauk] was an alternative title from 1940 to 1963.
There is an English language translation called Russian Chemical Bulletin [Russ. Chem.
Bull.] (1993–); from July 2000, also called Russian Chemical Bulletin, International
Edition. Formerly Bulletin of the Academy of Sciences of the USSR, Division of Chemical
Sciences [Bull. Acad. Sci. USSR, Div. Chem. Sci. (Engl. Transl.)]. The Russian language
version has no volume numbers; volume numbers were assigned to the translation from
1971 (Vol. 20). Publisher: Russian Academy of Sciences/Springer.
Japanese Journal of Antibiotics. See Journal of Antibiotics.
Japanese Journal of Chemistry. See Nippon Kagaku Kaishi.
Journal de Pharmacie et de Chimie. See Annales Pharmaceutiques Français.
Journal für Praktische Chemie. See Advanced Synthesis & Catalysis.
Journal of Agricultural and Food Chemistry [J. Agric. Food Chem.] (1953–). Publisher: ACS.
Journal of Antibiotics [J. Antibiot.] (1948–). English language translation of the Japanese
language journal Japanese Journal of Antibiotics [Jpn. J. Antibiot.]. From 1953 to 1967

Primary Journals

published as Series A [J. Antibiot., Ser. A] (English language) and Series B [J. Antibiot.,
Ser. B ] (Japanese language). Publisher: Japan Antibiotics Research Association, Tokyo.
Journal of Asian Natural Products Research [J. Asian Nat. Prod. Res.] (1998–). Publisher:
Taylor & Francis.
Journal of Biochemistry [J. Biochem. (Tokyo)] (1922–). Publisher: The Japanese Biochemical
Society/Oxford University Press.
Journal of Biological Chemistry [J. Biol. Chem.] (1905–). Free online full-text archive.
Publisher: The American Society for Biochemistry and Molecular Biology.
Journal of Carbohydrate Chemistry [J. Carbohydr. Chem.] (1982–). Successor to Journal
of Carbohydrates, Nucleosides, Nucleotides [J. Carbohydr., Nucleosides, Nucleotides]
(1974–1981), which was divided into Journal of Carbohydrate Chemistry and Nucleosides
& Nucleotides [Nucleosides Nucleotides] (1982–1999), later Nucleosides, Nucleotides &
Nucleic Acids [Nucleosides, Nucleotides Nucleic Acids]. Publisher: Taylor & Francis.
Journal of Chemical Crystallography [J. Chem. Crystallogr.] (1994–). Formerly Journal
of Crystal and Molecular Structure [J. Cryst. Mol. Struct.] (1971–1981) and Journal of
Crystallographic and Spectroscopic Research [J. Crystallogr. Spectrosc. Res.] (1982–1993).
Publisher: Springer.
Journal of Chemical Ecology [J. Chem. Ecol.] (1975–). Publisher: Springer.
Journal of Chemical Education [J. Chem. Educ.] (1924–). Publisher: ACS Division of
Chemical Education.
Journal of Chemical Research [J. Chem. Res.] (2004–). Formerly Journal of Chemical
Research, Miniprint [J. Chem. Res., Miniprint] (1977–2003) (a miniprint/microfiche,
full-text version) and Journal of Chemical Research, Synopsis [J. Chem. Res., Synop.]
(1977–2003) (a synopsis version). No volume numbers. Publisher: Science Reviews 2000
Ltd., UK.
Journal of Chemical Sciences [J. Chem. Sci. (Bangalore, India)] (2004–). Formerly
Proceedings—Indian Academy of Sciences, Section A [Proc.—Indian Acad. Sci., Sect. A]
(1934–1979) and Proceedings—Indian Academy of Sciences, Chemical Sciences [Proc.—
Indian Acad. Sci., Chem. Sci.] (1980–2003). Free online full-text archive from 1977.
Publisher: Indian Academy of Sciences/Springer.
Journal of Chemistry of the United Arab Republic. See Egyptian Journal of Chemistry.
Journal of Fluorine Chemistry [J. Fluorine Chem.] (1971–). Publisher: Elsevier.
Journal of General Chemistry of the USSR. See Zhurnal Obshchei Khimii.
Journal of Heterocyclic Chemistry [J. Heterocycl. Chem.] (1964–). Publisher:
HeteroCorporation, USA/Wiley.
Journal of Labelled Compounds and Radiopharmaceuticals [J. Labelled Compd.
Radiopharm.] (1976–). Formerly Journal of Labelled Compounds [J. Labelled Compd.]
(1965–1975). Publisher: Wiley.
Journal of Lipid Mediators and Cell Signalling [J. Lipid Mediators Cell Signalling]
(1994−1997). Formerly Journal of Lipid Mediators [J. Lipid Mediators] (1989–1993).
Merged with Prostaglandins [Prostaglandins] (1972–1997) to become Prostaglandins &
Other Lipid Mediators.
Journal of Lipid Research [J. Lipid Res.] (1959–). Free online full-text archive. Publisher:
The American Society for Biochemistry and Molecular Biology.
Journal of Magnetic Resonance [J. Magn. Reson.] (1969–1992, 1997–). Formerly divided
into Series A [J. Magn. Reson., Ser. A] (1993–1996) and Series B [J. Magn. Reson., Ser. B]
(1993–1996). Publisher: Elsevier.
Journal of Mass Spectrometry [J. Mass Spectrom.] (1995–). Formerly Organic Mass
Spectrometry [Org. Mass Spectrom.] (1968–1994). Incorporates Biological Mass Spec
trometry [Biol. Mass Spectrom.] [1991–1994], formerly Biomedical Mass Spectrometry

Organic Chemist's Desk Reference, Second Edition

[Biomed. Mass Spectrom.] (1974–85) and Biomedical and Environmental Mass SpecÂ�
trometry [Biomed. Environ. Mass Spectrom.] (1986–). Publisher: Wiley.
Journal of Medicinal Chemistry [J. Med. Chem.] (1963–). Formerly Journal of Medicinal
and Pharmaceutical Chemistry [J. Med. Pharm. Chem.] (1959–1962). Publisher: ACS.
Journal of Medicinal Plant Research. See Planta Medica.
Journal of Molecular Structure [J. Mol. Struct.] (1967–). From 1981 onward, some volumes have been published as THEOCHEM [THEOCHEM]; each of these volumes has
a Journal of Molecular Structure volume number and a different THEOCHEM volume
number. Publisher: Elsevier.
Journal of Natural Medicines [J. Nat. Med.] (2006–). Formerly Shoyakugaku Zasshi
[Shoyakugaku Zasshi], Journal of Pharmacognosy (1952–1993) and Natural Medicines
[Nat. Med., Tokyo, Jpn.] (1994–2005). Publisher: Springer, Japan.
Journal of Natural Products [J. Nat. Prod.] (1979–). Formerly Lloydia [Lloydia] (1938–
1978). Publisher: ACS.
Journal of Natural Products [J. Nat. Prod. (Gorakhpur, India)] (2008–). Electronic journal. Open access. Free online full-text issues at www.JournalOfNaturalProducts.com. Not
related to the Journal of Natural Products published by ACS.
Journal of Organic Chemistry [J. Org. Chem.] (1936–). Publisher: ACS.
Journal of Organic Chemistry of the USSR. See Zhurnal Organicheskoi Khimii.
Journal of Organometallic Chemistry [J. Organomet. Chem.] (1963–). Publisher: Elsevier.
Journal of Peptide Research [J. Pept. Res.] (1997–2005). Formed by the merger of
International Journal of Peptide and Protein Research and Peptide Research. Superseded
by Chemical Biology & Drug Design. Online archive publisher: Wiley.
Journal of Peptide Science [J. Pept. Sci.] (1995–). Publisher: European Peptide Society
and Wiley.
Journal of Pharmaceutical Sciences [J. Pharm. Sci.] (1961–). Publisher: American PharmaÂ�
cists Association/Wiley.
Journal of Pharmacy and Pharmacology [J. Pharm. Pharmacol.] (1929–). From 1929 to
1948, the title was Quarterly Journal of Pharmacy and Pharmacology [Q. J. Pharm.
Pharmacol.]. Publisher: Pharmaceutical Press.
Journal of Physical Organic Chemistry [J. Phys. Org. Chem.] (1988–). Publisher: Wiley.
Journal of Scientific and Industrial Research. See Indian Journal of Chemistry.
Journal of Steroid Biochemistry and Molecular Biology [J. Steroid Biochem. Mol. Biol.]
(1990–). Formerly Journal of Steroid Biochemistry [J. Steroid Biochem.] (1969–90).
Publisher: Elsevier.
Journal of Sulfur Chemistry [J. Sulfur Chem.] (Vol. 25–, 2004–). Formed by the merger
of Sulfur Letters [Sulfur Lett.] (Vols. 1–26, 1982–2003) and Sulfur Reports [Sulfur Rep.]
(Vols. 1–24, 1980–2003). Publisher: Taylor & Francis.
Journal of Synthetic Organic Chemistry. See Yuki Gosei Kagaku Kyokaishi.
Journal of the American Chemical Society [J. Am. Chem. Soc.] (1879–). Absorbed American
Chemical Journal [Am. Chem. J.] (1879–1913). Publisher: ACS.
Journal of the Brazilian Chemical Society [J. Braz. Chem. Soc.] (1990–). Free online fulltext archive. Publisher: Brazilian Chemical Society.
Journal of the Chemical Society [J. Chem. Soc.] (Vols. 1–32, 1849–1877, 1926–1965). Vol. 1
also assigned to the year 1848. Volume numbers were discontinued in 1925. From 1849
to 1862, an alternative title was Quarterly Journal, Chemical Society [Q. J., Chem. Soc.]
(1849–1862). From 1878 to 1925, issued as Journal of the Chemical Society, Transactions
[J. Chem. Soc., Trans.] (Vols. 33−127, 1878–1925) and Journal of the Chemical Society,
Abstracts [J. Chem. Soc., Abstr.] (Vols. 34–128, 1878–1925). (Odd-numbered volume
numbers only used for the Transactions; even-numbered volume numbers only used for
the Abstracts). In 1966, divided into Part A [J. Chem. Soc. A] (1966–1971) (inorganic),

Primary Journals

Part B [J. Chem. Soc. B] (1966–1971) (physical organic), and Part C [J. Chem. Soc. C]
(1966–1971) (organic). Chemical Communications [Chem. Commun.] (1965–1969) became
Part D [J. Chem. Soc. D] (1970–1971). In 1972, Parts A–D were superseded by Journal of
the Chemical Society, Dalton Transactions [J. Chem. Soc., Dalton Trans.] (1972–2002)
(inorganic); Journal of the Chemical Society, Perkin Transactions 1 [J. Chem. Soc.,
Perkin Trans. 1] (1972–2002) (organic and bioorganic); Journal of the Chemical Society,
Perkin Transactions 2 [J. Chem. Soc., Perkin Trans. 2] (1972–2002) (physical organic);
and Journal of the Chemical Society, Chemical Communications [J. Chem. Soc., Chem.
Commun.] (1972–1995) (preliminary communications), respectively. In 1996, Journal of
the Chemical Society, Chemical Communications became Chemical Communications
(Cambridge). In 2003, Journal of the Chemical Society, Dalton Transactions became
Dalton Transactions, and Journal of the Chemical Society, Perkin Transactions 1 and
Journal of the Chemical Society, Perkin Transactions 2 merged to become Organic &
Biomolecular Chemistry. Online archive publisher: RSC.
Journal of the Chemical Society, Faraday Transactions [J. Chem. Soc., Faraday Trans.]
(Vols. 86–94, 1990–1998). Formerly Transactions of the Faraday Society [Trans. Faraday
Soc.] (Vols. 1–67, 1905–1971). In 1972, divided into two parts: Journal of the Chemical
Society, Faraday Transactions 1 [J. Chem. Soc., Faraday Trans. 1] (Vols. 68–85, 1972–
1989) and Journal of the Chemical Society, Faraday Transactions 2 [J. Chem. Soc.,
Faraday Trans. 2] (Vols. 68–85, 1972–1989). In 1999, merged with Berichte der BunsenGesellschaft to form Physical Chemistry Chemical Physics. Online archive publisher: RSC.
Journal of the Chemical Society of Japan. See Nippon Kagaku Kaishi.
Journal of the Chemical Society of Pakistan [J. Chem. Soc. Pak.] (1979–). Publisher:
Chemical Society of Pakistan.
Journal of the Chinese Chemical Society (Peking). See Huaxue Xuebao.
Journal of the Chinese Chemical Society (Taipei) [J. Chin. Chem. Soc. (Taipei)] (1954–). In
English. Free online full-text issues from 1988. Publisher: The Chemical Society, Taipei, Taiwan.
Journal of the Indian Chemical Society [J. Indian Chem. Soc.] (Vol. 5–, 1928–). Formerly
Quarterly Journal of the Indian Chemical Society [Q. J. Indian Chem. Soc.] (Vols. 1–4,
1924–1927). Publisher: The Indian Chemical Society.
Journal of the Pharmaceutical Society of Japan. See Yakugaku Zasshi.
Journal of the Royal Netherlands Chemical Society. See Recueil des Travaux Chimiques
des Pays-Bas.
Journal of the Science of Food and Agriculture [J. Sci. Food Agric.] (1950–). Publisher: The
Society of Chemical Industry/Wiley.
Journal of the Society of Chemical Industry. See Chemistry & Industry.
Journal of the South African Chemical Institute. See South African Journal of Chemistry.
Justus Liebigs Annalen der Chemie. See Liebigs Annalen.
Khimiko-Farmatsevticheskii Zhurnal (Khim.-Farm. Zh.) (1967–). In Russian. There is an
English language translation called Pharmaceutical Chemistry Journal [Pharm. Chem. J.
(Engl. Transl.)] (1967–). Translation published by Springer.
Khimiya Geterotsiklicheskikh Soedinenii [Khim. Geterotsikl. Soedin.] (1965–). In Russian.
There is an English language translation called Chemistry of Heterocyclic Compounds
[Chem. Heterocycl. Compd.] (1965–). The translation has volume numbers; the Russian
language version has no volume numbers. Translation published by Springer.
Khimiya Prirodnykh Soedinenii [Khim. Prir. Soedin.] (1965–). In Russian. There is an
English language translation called Chemistry of Natural Compounds [Chem. Nat.
Compd.] (1965–). Translation published by Springer.
Kogyo Kagaku Zasshi [Kogyo Kagaku Zasshi] (1898–1971) (Journal of Industrial Chemistry).
In Japanese. No longer published. Merged with Nippon Kagaku Zasshi to form Nippon
Kagaku Kaishi.

Organic Chemist's Desk Reference, Second Edition

Liebigs Annalen [Liebigs Ann.] (1995–1996). Formerly Annalen der Pharmacie [Ann. Pharm.
(Lemgo, Ger.)] (Vols. 1–32, 1832–1839) and Justus Liebigs Annalen der Chemie [Justus
Liebigs Ann. Chem.] (1840–1978). Sometimes referred to colloquially as Annalen. Other
former titles, not adopted by CASSI, are Annalen der Chemie und Pharmacie [Ann. Chem.
Pharm.] (1840–1873) and Justus Liebigs Annalen der Chemie und Pharmacie [Justus
Liebigs Ann. Chem. Pharm.] (1873–1874). In 1979, became Liebigs Annalen der Chemie
[Liebigs Ann. Chem.] (1979–1994), which was superseded by Liebigs Annalen [Liebigs
Ann.] (1995–1996). Volume numbers were used until 1972 (Vol. 766). In 1997, merged with
Recueil des Travaux Chimiques des Pays-Bas to form Liebigs Annalen/Recueil [Liebigs
Ann./Recl.] (1997). No longer published. In 1998, superseded by European Journal of
Organic Chemistry. Online archive publisher: Wiley.
Letters in Organic Chemistry [Lett. Org. Chem.] (2004–). Publisher: Bentham Science
Publishers Ltd.
Letters in Peptide Science. See International Journal of Peptide Research and Therapeutics.
Liebigs Annalen/Recueil. See Liebigs Annalen.
Lipids [Lipids] (1966–). Publisher: American Oil Chemists’ Society/Springer.
Lloydia. See Journal of Natural Products.
Magnetic Resonance in Chemistry [Magn. Reson. Chem.] (Vol. 23–, 1985–). Formerly
Organic Magnetic Resonance [Org. Magn. Reson.] (1969–1984). Publisher: Wiley.
Magyar Kemiai Folyoirat [Magy. Kem. Foly.] (1895–) (Hungarian Journal of Chemistry). Until
1949, the title was Magyar Chemiai Folyoirat [Magy. Chem. Foly.]. Free online full-text
issues (in English and in Hungarian) from 2004. Publisher: Kultura, Budapest, Hungary.
Marine Drugs [Mar. Drugs] (2003–). Free online full-text archive from 2003. Publisher:
Molecular Diversity Preservation International (MDPI), Basel, Switzerland.
Mendeleev Communications [Mendeleev Commun.] (1991–). Publisher: Russian Academy
of Sciences/Elsevier.
Molbank [Molbank] (2002–). Formerly a section of Molecules. Electronic journal. Open
access. Free online full-text archive from 2002. Publisher: Molecular Diversity Preservation
International (MDPI), Basel, Switzerland.
Molecules [Molecules] (1996–). Electronic journal. Open access. Free online full-text archive
from 1996. Publisher: Molecular Diversity Preservation International (MDPI), Basel,
Switzerland.
Monatshefte für Chemie [Monatsh. Chem.] (1880–). From 1880 to 1967, the title, which
was not adopted by CASSI, was Monatshefte für Chemie und Verwandte Teile Anderer
Wissenschaften [Monatsh. Chem. Verw. Teile Anderer Wiss.]. Publisher: Springer.
Natural Product Communications [Nat. Prod. Commun.] (2006–). Publisher: Natural Product,
Inc., Westerville, Ohio.
Natural Product Letters. See Natural Product Research.
Natural Product Reports [Nat. Prod. Rep.] (1984–). Review journal. Publisher: RSC.
Natural Product Research [Nat. Prod. Res.] (2003–2006). From 2006, issued as Part A [Nat.
Prod. Res., Part A] and Part B [Nat. Prod. Res., Part B]. Formerly Natural Product Letters
[Nat. Prod. Lett.] (1992–2002). Publisher: Taylor & Francis.
Natural Product Sciences [Nat. Prod. Sci.] (1995–). Publisher: Korean Society of
Pharmacognosy, Seoul, South Korea.
Nature [Nature (London)] (1869–). Publisher: Nature Publishing Group/Macmillan
Publishers Ltd.
Nature Chemical Biology [Nat. Chem. Biol.] (2005–). Publisher: Nature Publishing Group/
Macmillan Publishers Ltd.
Nature Chemistry [Nat. Chem.] (2009–). Publisher: Nature Publishing Group/Macmillan
Publishers Ltd.
Naturwissenschaften [Naturwissenschaften] (1913–). Publisher: Springer.

Primary Journals

New Journal of Chemistry [New J. Chem.] (1987–). Formerly Nouveau Journal de Chimie
[Nouv. J. Chim.] (1977–1986). Publisher: RSC.
Nippon Kagaku Kaishi [Nippon Kagaku Kaishi] (1972Â�–2002) (Journal of the Chemical
Society of Japan). In Japanese. No English language translation is available. Formed by the
merger of Nippon Kagaku Zasshi [Nippon Kagaku Zasshi] (Japanese Journal of Chemistry)
(1948–1971) and Kogyo Kagaku Zasshi. Formerly Tokyo Kagaku Kaishi [Tokyo Kagaku
Kaishi] (1880–1920) (Journal of the Tokyo Chemical Society) and Nippon Kagaku Kaishi
(1921–47) [Nippon Kagaku Kaishi (1921–47)] (1921–1947). In pre-1960s issues of Chemical
Abstracts, called Journal of the Chemical Society of Japan [J. Chem. Soc. Jpn.]. No longer
published. Free online full-text archive 1880–2002 from J-Stage at http://www.jstage.jst.
go.jp/browse/.
Norvegica Pharmaceutica Acta. See European Journal of Pharmaceutical Sciences.
Nouveau Journal de Chimie. See New Journal of Chemistry.
Nucleosides, Nucleotides & Nucleic Acids [Nucleosides, Nucleotides Nucleic Acids]
(Vol. 19–, 2000−). Formerly Journal of Carbohydrates, Nucleosides, Nucleotides
[J. Carbohydr., Nucleosides, Nucleotides] (1974–1981), which was divided into NucleoÂ�
sides & Nucleotides [Nucleosides Nucleotides] (Vols. 1–18, 1982–1999) and Journal of
Carbohydrate Chemistry [J. Carbohydr. Chem.]. Publisher: Taylor & Francis.
Open Medicinal Chemistry Journal [Open Med. Chem. J.] (2007–). Electronic journal. Open
access. Free online full-text archive from 2007. Publisher: Bentham Open.
Open Natural Products Journal [Open Nat. Prod. J.] (2008–). Electronic journal. Open
access. Free online full-text archive from 2008. Publisher: Bentham Open.
Open Organic Chemistry Journal [Open Org. Chem. J.] (2007–). Electronic journal. Open
access. Free online full-text archive from 2007. Publisher: Bentham Open.
Organic & Biomolecular Chemistry [Org. Biomol. Chem.] (Vol. 1–, 2003–). Formed by a
merger of Journal of the Chemical Society, Perkin Transactions 1 and Journal of the
Chemical Society, Perkin Transactions 2. See also Journal of the Chemical Society.
Publisher: RSC.
Organic Magnetic Resonance. See Magnetic Resonance in Chemistry.
Organic Mass Spectrometry. See Journal of Mass Spectrometry.
Organic Preparations and Procedures International [Org. Prep. Proced. Int.] (1971–).
Formerly Organic Preparations and Procedures [Org. Prep. Proced.] (1969–70). Publisher:
Taylor & Francis.
Organic Communications [Org. Commun.] (2007–). Electronic journal. Open access. Free
online full-text archive from 2008. Publisher: Academy of Chemistry of Globe, Turkey.
Organic Letters [Org. Lett.] (1999–). Publisher: ACS.
Organic Process Research & Development [Org. Process Res. Dev.] (1997–). Publisher: ACS.
Organometallics [Organometallics] (1982–). Publisher: ACS.
Oriental Journal of Chemistry [Orient. J. Chem.] (1985–). Publisher: Oriental Scientific
Publishing Company, Bhopal, Madhya Pradesh, India.
Peptide Research. See International Journal of Peptide and Protein Research.
Peptides [Peptides (Amsterdam, Neth.)] (2007–). Previous CASSI abbreviations include
Peptides (N. Y.) (1980–2006). Publisher: Elsevier.
Pharmaceutical Bulletin. See Chemical and Pharmaceutical Bulletin.
Pharmazie [Pharmazie] (1946–). Publisher: Govi-Verlag Pharmazeutischer Verlag,
Eschborn, Germany.
Phosphorus, Sulfur and Silicon and the Related Elements [Phosphorus, Sulfur Silicon Relat.
Elem.] (1989–). Formerly Phosphorus and Sulfur and the Related Elements [Phosphorus
Sulfur Relat. Elem.] (1976–1988), which was formed by a merger of Phosphorus and
the Related Group V Elements [Phosphorus Relat. Group V Elem.] (1971–1976) and
International Journal of Sulfur Chemistry [Int. J. Sulfur Chem.] (1973–1976). International

Organic Chemist's Desk Reference, Second Edition

Journal of Sulfur Chemistry was previously divided into Part A [Int. J. Sulfur Chem.,
Part A] (1971–1972) (original experimental and theoretical studies); Part B [Int. J. Sulfur
Chem., Part B] (1971–1972), previously Quarterly Reports on Sulfur Chemistry [Q. Rep.
Sulfur Chem.] (1966–1970); and Part C [Int. J. Sulfur Chem., Part C] (1971–1972), previously Mechanisms of Reactions of Sulfur Compounds [Mech. React. Sulfur Compd.]
(1966–1970). Publisher: Taylor & Francis.
Physical Chemistry Chemical Physics [Phys. Chem. Chem. Phys.] (Vol. 1–, 1999–). Formed
by the merger of Berichte der Bunsen-Gesellschaft and Journal of the Chemical Society,
Faraday Transactions. Publisher: RSC (in cooperation with other scientific societies).
Phytochemistry [Phytochemistry] (1961–). Publisher: Elsevier.
Phytochemistry Letters [Phytochem. Lett.] (2008–). Publisher: Phytochemical Society of
Europe/Elsevier.
Planta Medica [Planta Med.] (1953–). Sometimes referred to as Journal of Medicinal Plant
Research: Planta Medica [J. Med. Plant Res.: Planta Med.]. Publisher: Thieme.
Polish Journal of Chemistry [Pol. J. Chem.] (1978–2009). Formerly Roczniki Chemii [Rocz.
Chem.] (1921–77). Publisher: Polish Chemical Society. No longer published. Superseded by
European Journal of Inorganic Chemistry and European Journal of Organic Chemistry.
Polyhedron [Polyhedron] (1982–). Successor to Journal of Inorganic and Nuclear Chemistry
[J. Inorg. Nucl. Chem.] (1955–81) and Inorganic and Nuclear Chemistry Letters [Inorg.
Nucl. Chem. Lett.] (1965–81). Publisher: Elsevier.
Proceedings of the Chemical Society, London [Proc. Chem. Soc, London] (1885–1914,
1957–1964). Superseded by Chemical Communications [Chem. Commun.] (1965–1969).
From 1915 to 1956 there was a proceedings section in Journal of the Chemical Society. See
also Chemical Communications (Cambridge).
Proceedings of the National Academy of Sciences of the United States of America [Proc.
Natl. Acad. Sci. U.S.A.] (1863–). Free online full-text archive (online issues available
six months after the print publication; some current full-text content also free online).
Publisher: National Academy of Sciences, United States.
Prostaglandins & Other Lipid Mediators [Prostaglandins Other Lipid Mediators] (1998–).
Formed by a merger of Prostaglandins [Prostaglandins] (1972–1997) and Journal of Lipid
Mediators and Cell Signalling [J. Lipid Mediators Cell Signalling] (1994−97). Publisher:
Elsevier.
Protein & Peptide Letters [Protein Pept. Lett.] (1994–). Publisher: Bentham Science
Publishers Ltd.
Pure and Applied Chemistry [Pure Appl. Chem.] (1960–). Free online full-text archive.
Publisher: IUPAC.
Quarterly Reviews of the Chemical Society. See Chemical Society Reviews.
Records of Natural Products [Rec. Nat. Prod.] (2007–). Electronic journal. Open access. Free
online full-text archive from 2007. Publisher: Academy of Chemistry of Globe, Turkey.
Recueil des Travaux Chimiques des Pays-Bas [Recl. Trav. Chim. Pays-Bas] (1882–1996).
Also known as Journal of the Royal Netherlands Chemical Society [J. R. Neth. Chem.
Soc.]. From 1897 to 1919, the title was Recueil des Travaux Chimiques des Pays-Bas et
de la Belgique [Recl. Trav. Chim. Pays-Bas Belg.], and from 1980 to 1984, the title was
Recueil: Journal of the Royal Netherlands Chemical Society [Recl.: J. R. Neth. Chem.
Soc.]. No longer published. Merged with Chemische Berichte [Chem. Ber.] to form
Chemische Berichte/Recueil and with Liebigs Annalen [Liebigs Ann.] to form Liebigs
Annalen/Recueil.
Regulatory Peptides [Regul. Pept.] (1980–). Publisher: Elsevier.
Revue Roumaine de Chimie [Rev. Roum. Chem.] (1964–). Formerly Revue de Chimie, Academie
de la Republique Populaire Roumaine [Rev. Chim. Acad. Repub. Pop. Roum.] (1954–1963).
Also known as Roumanian Journal of Chemistry. Publisher: Romanian Academy.

Primary Journals

Roczniki Chemii. See Polish Journal of Chemistry.
Rossiiskii Khimicheskii Zhurnal [Ross. Khim. Zh.] (Russian Chemical Journal) (1993–).
In Russian. Formerly Zhurnal Vsesoyuznogo Khimicheskogo Obshchestva im. D. I.
Mendeleeva [Zh. Vses. Khim. O–va. im. D. I. Mendeleeva] (1960–1991) (Journal of the D.
I. Mendeleev All-Union Chemical Society). In Russian. There is an English language translation entitled Mendeleev Chemistry Journal [Mendeleev Chem. J.] (1966–). Translation
published by Allerton Press, Inc., New York.
Russian Chemical Bulletin. See Izvestiya Akademii Nauk, Seriya Khimicheskaya.
Russian Chemical Reviews. See Uspekhi Khimii.
Russian Journal of Applied Chemistry. See Zhurnal Prikladnoi Khimii.
Russian Journal of Bioorganic Chemistry. See Bioorganicheskaya Khimiya.
Russian Journal of General Chemistry. See Zhurnal Obshchei Khimii.
Russian Journal of Inorganic Chemistry. See Zhurnal Neorganicheskoi Khimii.
Russian Journal of Organic Chemistry. See Zhurnal Organicheskoi Khimii.
Science [Science (Washington, D.C.)] (1883–). Publisher: American Association for the
Advancement of Science. http://www.sciencemag.org/.
Scientia Pharmaceutica [Sci. Pharm.] (1930–). Free online full-text archive from 2006.
Publisher: The Austrian Journal of Pharmaceutical Sciences.
South African Journal of Chemistry [S. Afr. J. Chem.] (1977–). Formerly Journal of the
South African Chemical Institute [J. S. Afr. Chem. Inst.] (1922–1976). Free online full-text
archive from 2001. Publisher: South African Bureau for Scientific Publications.
Soviet Journal of Bioorganic Chemistry. See Bioorganicheskaya Khimiya.
Spectrochimica Acta [Spectrochim. Acta] (1939–1966). From Vol. 23, divided into Part
A [Spectrochim. Acta, Part A] (1967–) (molecular spectroscopy; from 1995, subtitle is
Molecular and Biomolecular Spectroscopy) and Part B [Spectrochim. Acta, Part B]
(1967–) (atomic spectroscopy). Publisher: Elsevier.
Steroids [Steroids] (1963–). Publisher: Elsevier.
Synfacts [Synfacts] (2005–). Publisher: Thieme.
Synlett [Synlett] (1989–). No volume numbers. Publisher: Thieme.
Synthesis [Synthesis] (1969–). No volume numbers. Publisher: Thieme.
Synthesis and Reactivity in Inorganic, Metal-Organic, and Nano-Metal Chemistry [Synth.
React. Inorg., Met.-Org., Nano-Met. Chem.] (2005–). Formerly Synthesis in Inorganic and
Metal-Organic Chemistry [Synth. Inorg. Met.-Org. Chem.] (1971–1973) and Synthesis and
Reactivity in Inorganic and Metal-Organic Chemistry [Synth. React. Inorg. Met.-Org.
Chem.] (1974–2004). Publisher: Taylor & Francis.
Synthetic Communications [Synth. Commun.] (1971–). Publisher: Taylor & Francis.
Tetrahedron [Tetrahedron] (1957–). From 1958 to 1962, more than one volume number was
issued each year: 1957, Vol. 1; 1958, Vols. 2–4; 1959, Vols. 5–7; 1960, Vols. 8–11; 1961,
Vols. 12–16; 1962, Vols. 17–18; 1963, Vol. 19 et seq.; 2009, Vol. 65. Publisher: Elsevier.
Tetrahedron: Asymmetry [Tetrahedron: Asymmetry] (1990–). Publisher: Elsevier.
Tetrahedron Letters [Tetrahedron Lett.] (1959–). In the print edition, volume numbers were first
used in 1980 (Vol. 21). In the online edition, volume numbers were assigned from 1959–1960
(called Vol. 1). The forty-eight issues for 1959–1960 were paginated separately, and the issue
numbering differs between the print and online editions: print edition, Issues 1–21 (1959);
Issues 1–27 (1960); online edition, Issues 1–21 (1959); Issues 22–48 (1960). Publisher: Elsevier.
Tetrahedron, Supplement [Tetrahedron, Suppl.] (1958–1981). Irregular. No volume numbers.
No longer published.
THEOCHEM. See Journal of Molecular Structure.
Turkish Journal of Chemistry [Turk. J. Chem.] (1992–). Formerly Doga: Turk Kimya Dergisi
(and related titles). Free online full-text archive from 1996. Publisher: The Scientific and
Technological Research Council of Turkey.

Organic Chemist's Desk Reference, Second Edition

United Arab Republic Journal of Chemistry. See Egyptian Journal of Chemistry.
Uspekhi Khimii [Usp. Khim.] (1932–). In Russian. There is an English language translation entitled Russian Chemical Reviews [Russ. Chem. Rev.] (1960–). Publisher: Russian
Academy of Sciences/Turpion Ltd., London.
Yakugaku Zasshi [Yakugaku Zasshi] (1881–) (Journal of Pharmacy). Also known as Journal
of the Pharmaceutical Society of Japan. In Japanese. No English language translation is
available. Free online full-text archive from 1881. Publisher: The Pharmaceutical Society
of Japan, Tokyo.
Yuki Gosei Kagaku Kyokaishi [Yuki Gosei Kagaku Kyokaishi] (1943–). Also known as Journal
of Synthetic Organic Chemistry [J. Synth. Org. Chem. Jpn.]. In Japanese. No English language translation of the full text is available, but tables of contents in English from 2000 are
on the publisher’s website. Publisher: The Society of Synthetic Organic Chemistry, Japan.
Zeitschrift für Angewandte Chemie. See Angewandte Chemie.
Zeitschrift für Anorganische und Allgemeine Chemie [Z. Anorg. Allg. Chem.] (1892–).
From 1892 to 1915 and 1943 to 1950, the title was Zeitschrift für Anorganische Chemie
[Z. Anorg. Chem.]. Publisher: Wiley.
Zeitschrift für Chemie. See Angewandte Chemie.
Zeitschrift für Kristallographie [Z. Kristallogr.] (1978–). Formerly titled Zeitschrift für
Kristallographie und Mineralogie [Z. Kristallogr. Mineral.] (1877–1915) and Zeitschrift
für Kristallographie, Kristallgeometrie, Kristallphysik, Kristallchemie [Z. Kristallogr.,
Kristallgeom., Kristallphys., Kristallchem.] (1921–1977; not published 1945–1954). Also
called Zeitschrift für Kristallographie, Mineralogie und Petrographie, Abteilung A
[Z. Kristallogr. Mineral. Petrogr, Abt. A] (1930–1945). Publisher: Oldenbourg Verlagsgruppe.
Zeitschrift für Kristallographie: New Crystal Structures [Z. Kristallogr. New Cryst. Struct.]
(1997–). Publisher: Oldenbourg Verlagsgruppe.
Zeitschrift für Naturforschung [Z. Naturforsch.] (1946). In 1947, divided into Teil A
[Z. Naturforsch., A] (1947–) (physical sciences) and Teil B [Z. Naturforsch., B] (1947–)
(chemical sciences), to which was later added Teil C [Z. Naturforsch., C] (1973–) (biosciences—previously included in Teil B). (Additional CASSI abbreviated subtitles omitted.)
Publisher: Verlag der Zeitschrift für Naturforschung, Tübingen, Germany.
Zhurnal Neorganicheskoi Khimii [Zh. Neorg. Khim.] (1956–). In Russian. There is an
English language translation called Russian Journal of Inorganic Chemistry [Russ. J.
Inorg. Chem.] (1959–). Formerly Journal of Inorganic Chemistry (USSR) [J. Inorg. Chem.
(USSR)] (1956–1958). Publisher: MAIK Nauka/Interperiodica.
Zhurnal Obshchei Khimii [Zh. Obshch. Khim.] (1931–). In Russian. There is an English
language translation called Russian Journal of General Chemistry [Russ. J. Gen. Chem.]
(1993–). Formerly Journal of General Chemistry of the USSR [J. Gen. Chem. USSR
(Engl. Transl.)] (1949–1992). Publisher: Springer/MAIK Nauka/Interperiodica. The
antecedence of this title is Zhurnal Russkago Khimicheskago Obshchestva [Zh. Russ.
Khim. O–va.] (Vols. 1–4, 1869–1872); Zhurnal Russkago Khimicheskago Obshchestva i
Fizicheskago Obshchestva [Zh. Russ. Khim. O–va. Fiz. O–va.] (Vols. 5–10, 1873–1878);
Zhurnal Russkago Fiziko-Khimicheskago Obshchestva [Zh. Russ. Fiz.-Khim. O–va.]
(Vols. 11–38, 1879–1906); Zhurnal Russkogo Fiziko-Khimicheskago Obshchestva, Chast
Khimicheskaya [Zh. Russ. Fiz.-Khim. O–va., Chast Khim.] (Vols. 39–62, 1907–1930);
and Zhurnal Russkogo Fiziko-Khimicheskago Obshchestva, Chast Fizicheskaya [Zh.
Russ. Fiz.-Khim. O–va., Chast Fiz.] (Vols. 39–62, 1907–1930). Zhurnal Russkogo FizikoKhimicheskago Obshchestva, Chast Khimicheskaya was superseded by Zhurnal Obshchei
Khimii. Early volumes of Chemical Abstracts used an anglicized version for Zh. Russ.
Fiz.-Khim. O–va.: J. Russ. Phys.-Chem. Soc. or J. Russ. Phys. Chem. Soc. CASSI interchanges Russkogo and Russkago in the transliteration of these Russian titles.

Primary Journals

Zhurnal Organicheskoi Khimii [Zh. Org. Khim.] (1965–). In Russian. There is an English
language translation called Russian Journal of Organic Chemistry [Russ. J. Org. Chem.]
(1993–). Formerly Journal of Organic Chemistry of the USSR [J. Org. Chem. USSR (Engl.
Transl.)] (1965–92). Publisher: Springer/MAIK Nauka/Interperiodica.
Zhurnal Prikladnoi Khimii [Zh. Prikl. Khim. (St Petersburg)]. Formerly Zh. Prikl. Khim.
(Leningrad) (1928–). In Russian. There is an English language translation called Russian
Journal of Applied Chemistry [Russ. J. Appl. Chem.] (1993–). Formerly Journal of Applied
Chemistry of the USSR [J. Appl. Chem. USSR (Engl. Transl.)] (1950–1992). Publisher:
Springer/MAIK Nauka/Interperiodica.

Endnotes

1. CAS Source Index (CASSI) abbreviations. The most recent printed cumulative compendium of CASSI
abbreviated titles is for the period 1907–2004. Annual printed updates are also issued, and a CD version is available, in which the cumulative titles and the annual updates are combined (currently CASSI
on CD covers the period 1907–2008). From 2010, only the CD version of CASSI is published.
CASSI abbreviations for about 1,500 leading journals are listed on a free website (CAplus Core Journal
Coverage List).
Augmenting the CD version of CASSI is the CAS Source Index (CASSI) Search Tool (http://cassi.
cas.org/search.jsp). Available from January 2010, the CASSI search tool is a free, web-based resource
that can be used to quickly identify or confirm journal titles and abbreviations for publications indexed
by CAS since 1907, including serial and non-serial scientific and technical publications.
CASSI abbreviations sometimes include the geographical location of the publisher of a journal and
the subtitles of those journals, which are divided into named parts or sections. The details are omitted
here, apart from a few exceptions.
2. Some leading publishers of chemistry journals:

Publisher

Abbreviated Name

Internet Address

American Chemical Society, Washington D.C.
Elsevier, Oxford (and elsewhere)
John Wiley & Sons, Inc., Hoboken, NJ
(includes Wiley-Blackwell, Wiley
InterScience, Wiley-VCH)
MAIK Nauka/Interperiodica
Royal Society of Chemistry, Cambridge
Springer Publishing Company, New York and
Berlin
Taylor & Francis Group, London
Thieme Publishing Group, Stuttgart, Germany

ACS
Elsevier
Wiley

http://pubs.acs.org/
http://www.sciencedirect.com/science
http://eu.wiley.com/WileyCDA/
Section/index.html

…
RSC
Springer

http://www.maik.rssi.ru/
http://www.rsc.org/
http://www.springerpub.com/

Taylor & Francis
Thieme

http://www.taylorandfrancisgroup.com/
http://www.thieme-chemistry.com/

3. Electronic sources for chemistry journals. With very few exceptions, all the current printed chemistry
journals are available online, and some recent additions to the chemistry literature are only available
electronically. For the majority of titles, access to the online full text of a journal and its archive is by
paid subscription, but for an increasing number of chemistry journals, free online open access to current
issues and full-text archives, either partial or complete, is now allowed. For some authors, open access of
published papers on the web may be a condition of funding of their research.
Tables of contents for the current and archival issues of chemistry journals are free online, and usually abstracts are also provided by the publisher. Search engines give details of the Internet addresses
(URLs) for chemistry journals, and there are also websites that provide hyperlinks to most of the chemistry journals currently online, for example, Cambridge University’s Department of Chemistry website:
http://www.ch.cam.ac.uk/c2k/. Free full-text chemistry journals on the web are listed on the Belarusian
State University website: http://www.abc.chemistry.bsu.by/current/fulltext.htm. (The content and permanence of any website cannot be guaranteed, and Internet addresses are subject to modification.)

3 Nomenclature Fundamentals
Currently the best book available is Fox, R. B., and Powell, W. H., Nomenclature of Organic
Compounds, Principles and Practice, 2nd ed. New York (ACS/OUP, 2001).
This and the following chapters are intended as a quick reference guide, and should not replace
the International Union of Pure and Applied Chemistry (IUPAC) publications for definitive guidance
nor the CAS 2007 documentation for a full description of the current CAS nomenclature system.
The indexing and location of substances is now largely done by substructure, and the function
of nomenclature is much more to provide an acceptable name for a given compound in a particular
context. A given compound may have several equally valid names, and a name intelligible to a fellow organic chemist may not be appropriate for publication in, for example, fire regulations. For
many purposes it is sufficient to be able to recognise from the name that the correct compound has
been tracked down as a result of searching by substructure, molecular formula, etc.
• Do not needlessly proliferate systematic names.
• Make sure that you have checked all available information products to ensure that a compound you are reporting is in fact new. For synthetic compounds carry out a structure
search against Chemical Abstracts and Beilstein; for newly isolated natural products, the
Dictionary of Natural Products (see Section 1.2.1) is the best source.
• When reporting new natural products, avoid duplicating trivial names. Check against the
Dictionary of Natural Products and CAS.

3.1 IUPAC Nomenclature
IUPAC (www.iupac.org) promulgates general nomenclature recommendations. The IUPAC website
is particularly useful for classes of compounds where the nomenclature has its own specialised
rules, e.g., carbohydrates and organophosphorus compounds. IUPAC nomenclature is a series of
protocols, not a precise recipe, so it is often possible to arrive at two or more systematic names that
each accord with IUPAC recommendations.
The following IUPAC recommendations of principal interest to organic chemists are available
at www.iupac.org/publications:
Nomenclature of Organic Compounds (“The Blue Book”), incorporating IUPAC recommendations 1979 and 1993
Biochemical Nomenclature
Chemical Terminology (“The Gold Book”), with definitions of 7000 terms
See also the following printed publications:
A Guide to IUPAC Nomenclature of Organic Compounds, Blackwell Scientific, London, 1993.
Biochemical Nomenclature and Related Documents, Portland Press, London, 1992. Contains
about forty reprints of articles taken from journals, on nomenclature of amino acids, peptides, and carbohydrates. This information is now mostly available on websites.
Updates to IUPAC recommendations are published on the website, usually with a summary in
the IUPAC journal Chemistry International.
Algorithms are available that generate acceptable IUPAC names from structures, such as
MARVIN from ChemAxon (www.chemaxon.com/marvin).
41

Organic Chemist's Desk Reference, Second Edition

3.1.1 Numbering of Chains
The first four members of the alkane series (methane, ethane, propane, butane) are irregular; subsequent members are named systematically by attaching -ne to the list of numerical prefixes given
in Table3.1.
Table3.1
Common Numerical Prefixes
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26

mono
di
tri
tetra
penta
hexa
hepta
octa
nona
deca
undeca
dodeca
trideca
tetradeca
pentadeca
hexadeca
heptadeca
octadeca
nonadeca
eicosa or icosa
heneicosa or henicosa
docosa
tricosa
tetracosa
pentacosa
hexacosa

27
28
29
30
31
32
33
40
50
60
70
80
90
100
101
102
110
120
130
200
300
400
1,000
2,000
3,000
4,000

heptacosa
octacosa
nonacosa
triaconta
hentriaconta
dotriaconta
tritriaconta
tetraconta
pentaconta
hexaconta
heptaconta
octaconta
nonaconta
hecta
henhecta
dohecta
decahecta
eicosahecta or icosahecta
triacontahecta
dicta
tricta
tetracta
kilia
dilia
trilia
tetrilia

3.1.1.1 Multiplicative Prefixes from Greek and Latin
In CAS Index Names, Greek prefixes are preferred, except for sesqui- (for one and one-half), nona(for nine), and undeca- (for eleven). The terms hemi- (Greek) and sesqui- (Latin) are employed by
CAS only in hydrate and ammoniate names. A full list is given in Table3.2.
The terms bis, tris, tetrakis, etc. (meaning essentially “twice,” “three times,” etc.) are used to
avoid ambiguity in nomenclature. This is best illustrated by the following example:

Ph
N

Ph
O

1, 2-cyclohexanedione
diphenylhydrazone
(strictly, mono(diphenylhydrazone))

H
N

Ph
N

N
H

1, 2-cyclohexanedione
bis(phenylhydrazone)

In naming ring assemblies the alternative prefixes bi-, ter-, quater-, quinque-, and sexi- are used.

Nomenclature Fundamentals

Table3.2
Greek and Latin Multiplicative Prefixes
1/2
1
3/2
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24

Greek

Latin

hemi
mono, mon

semi
uni
sesqui
bi
tri, ter
quadric, quadr, quater
quinque, quinqu
sexi, sex
septi, sept

di
tri
tetra, tert
penta, pent
hexa, hex
hepta, hept
octa, oct, octo, octi
ennea, enne
deca, dec, deci
hendeca, hendec
dodeca, dodec
trideca, tridec
tetradeca, tetradec
pentadeca, pentadec
hexadeca, hexadec
heptadeca, heptadec
octadeca, octadec
nonadeca, nonadec
eicosa, eicos (or ic …)
henicosa, henicos
docosa, docos
tricosa, tricos
tetracosa, tetracos

Greek
25
26
27
28
29
30
31
32
33
40
50
60
70
80
90
100
101
102
110
120
132
200
300
400
1,000

nona, non, novi
undeca, undec

pentacosa, pentacos
hexacosa, hexacos
heptacosa, heptacos
octacosa, octacos
nonacosa, nonacos
triconta, triacont
hentriconta, hentriacont
dotriaconta, dotriacont
tritriaconta, tritriacont
tetraconta, tetracont
pentaconta, pentacont
hexaconta, hexacont
heptaconta, heptacont
octaconta, octacont
nonaconta, nonacont
hecta, hect
henhecta, henhect
dohecta, dohect
decahecta, decahect
eicosahecta, eicosahect (or ic …)
dotriacontahecta, dotriacontahect
dicta, dict
tricta
tetracta
kilia

3.1.2 Numbering of Substituents: IUPAC Principles
If a molecular skeleton can be numbered in more than one way, then it should be numbered so as to
give the substituents the lowest set of locants. The locants for all the substituents (regardless of what
the substituents are) are arranged in numerical order; the possible sets of locants are then compared
number by number until a difference is found.
Cl

F
Cl
Cl
Decane, 6,7,8,9-tetrachloro-1-fluoro-, not decane, 2,3,4,5-tetrachloro-10-fluoro-

3.1.3 Alphabetisation
Substituent prefixes are placed in alphabetical order according to their name; only then are numerical prefixes (di-, tri-, etc.) placed in front of each as required and the locants inserted.
Cl
Br

NO2
7

Br
Br

Organic Chemist's Desk Reference, Second Edition

The substituents are 1-chloro, 2-nitro, 4-bromo-, 6-(dibromomethyl)-, and 7-bromo-. The substituents are cited in alphabetical order, i.e., bromo, chloro, (dibromomethyl), nitro. The Index Name
is “Naphthalene, 4,7-dibromo-1-chloro-6-(dibromomethyl)-2-nitro-.”
(Dibromomethyl) is an example of a complex substituent, one that is made up of two or more
simple substituents. A complex substituent requires enclosing parentheses, and is alphabetised at
its first letter, regardless of the origin of this letter, e.g., b from (bromomethyl), d from (dibromomethyl), and t from (tribromomethyl).

3.1.4 Other Nomenclature Conventions
See Chapter 2 of Fox and Powell for the detailed application of the following IUPAC conventions
in organic names: spelling, italics, punctuation, enclosing marks, locants, and detachable and nondetachable prefixes.

3.2 CAS Nomenclature
CAS nomenclature in general accords with IUPAC principles and can be considered a special case
of it, but because CAS needs to arrive at a unique name for each substance, its rules are more definitive. In addition, CAS (in consultation with the American Chemical Society nomenclature committees) has to operate on a short time frame, and often has to introduce names in areas where IUPAC
has not yet formulated policy. Occasionally the IUPAC rules, when published, may differ from what
CAS has already done, and CAS may not adopt IUPAC recommendations when they are eventually
published. (For a fuller account, see Fox and Powell, pp. 6–7.)
Major changes in CAS nomenclature were made at the beginning of the ninth Collective Index
period (1972), giving what became widely known as 9CI nomenclature. This is described in the
publication Naming and Indexing of Chemical Substances for Chemical Abstracts (Appendix IV to
the CAS 1992 Index Guide, but also available separately).
Nomenclature was then largely stable for organic compounds until 2006; further changes introduced are described in Section 3.2.2 and at appropriate places in the next chapter. Current CAS
policy is described in the updated Naming and Indexing of Chemical Substances for Chemical
Abstract, 2007 edition, available at cas.org.
The use of CI suffixes in CAS to indicate the Collective Index period during which the name
was applied has now been discontinued, although labels 9CI, 8CI, etc., attached to existing names
remain in place.

3.2.1 Older Names Encountered in CAS Pre-1972
At the changeover from the eighth to the ninth Collective Index periods (1972), the use of many
older stem names was discontinued. These are all found in the older literature, and some can still
be found in the literature today. The list in Table 3.3 equates many 9CI name fragments with those
used in the 8CI and earlier. An asterisk indicates that the name was used in 8CI for the unsubstituted
substance only; substituted derivatives were indexed elsewhere.

Table 3.3
8CI Name

9CI Name

8CI Name

9CI Name

Acetamidine
Acetanilide
Acetanisidide
Acetoacetic acid

Ethanimidamine
Acetamide, N-phenylAcetamide, N-(methoxyphenyl)Butanoic acid, 3-oxo-

Acetonaphthone
Acetone*
Acetophenetidide
Acetophenone

Ethanone, 1-(naphthalenyl)2-Propanone
Acetamide, N-(ethoxyphenyl)Ethanone, 1-phenyl-

* Name used in 8CI for unsubstituted substance only.

Nomenclature Fundamentals

Table 3.3 (continued)
8CI Name

9CI Name

8CI Name

9CI Name

Acetotoluidide
Acetoxylidide
Acetylene
Acrolein
Acrylic acid
Adamantane
Adipic acid*
Allene*
Alloxan
Alloxazine
Allyl alcohol*
Allylamine
Aniline
Anisic acid
Anisidine
Anisole
Anthranilic acid
Anthraquinone
Anthroic acid
Anthrol
Anthrone
Atropic acid
Azelaic acid*
Azobenzene
Azoxybenzene

Acetamide, N-(methylphenyl)Acetamide, N-(dimethylphenyl)Ethyne
2-Propenal
2-Propenoic acid
Tricyclo[3.3.1.13,7]decane
Hexanedioic acid
1,2-Propadiene
2,4,5,6(1H,3H)-Pyrimidinetetrone
Benzo[g]pteridine-2,4(1H,3H)-dione
2-Propen-1-ol
2-Propen-1-amine
Benzenamine
Benzoic acid, methoxyBenzenamine, ar-methoxyBenzene, methoxyBenzoic acid, 2-amino9,10-Anthracenedione
Anthracenecarboxylic acid
Anthracenol
9(10H)-Anthracenone
Benzeneacetic acid, α-methyleneNonanedioic acid
Diazene, diphenylDiazene, diphenyl-, 1-oxide

Chromone
Cinchoninic acid
Cinnamic acid
Cinnamyl alcohol*
Citraconic acid*
Citric acid
Coumarin
Cresol
Cresotic acid
Crotonic acid
Cumene
Cumidine
Cymene
Cytosine

4H-1-Benzopyran-4-one
4-Quinolinecarboxylic acid
2-Propenoic acid, 3-phenyl2-Propen-1-ol, 3-phenyl2-Butenedioic acid, 2-methyl, (Z)1,2,3-Propanetricarboxylic acid, 2-hydroxy2H-1-Benzopyran-2-one
Phenol, methylBenzoic acid, hydroxymethyl2-Butenoic acid
Benzene, (1-methylethyl)Benzenamine, 4-(1-methylethyl)Benzene, methyl(1-methylethyl)2(1H)-Pyrimidinone, 4-amino-

Diacetamide
Dibenzamide
Diethylamine
Diethylene glycol*
Diimide
Dimethylamine
Divicine

Acetamide, N-acetylBenzamide, N-benzoylEthanamine, N-ethylEthanol, 2,2′-oxybisDiazene
Methanamine, N-methyl4,5-Pyrimidinedione, 2,6-diamino-1,6-dihydro-

Barbituric acid
Benzanilide
Benzhydrol
Benzidine
Benzil
Benzilic acid
Benzoin
Benzophenone
o-Benzoquinone
p-Benzoquinone
Benzyl alcohol
Benzylamine
Bibenzyl
Bornane
Butyl alcohol*
sec-Butyl alcohol*
tert-Butyl alcohol*
Butylamine
Butyraldehyde
Butyric acid
Butyrophenone

2,4,6(1H,3H,5H)-Pyrimidinetrione
Benzamide, N-phenylBenzenemethanol, α-phenyl[1,1′-Biphenyl]-4,4′-diamine
Ethanedione, diphenylBenzeneacetic acid, α-hydroxy-α-phenyl
Ethanone, 2-hydroxy-1,2-diphenylMethanone, diphenyl3,5-Cyclohexadiene-1,2-dione
2,5-Cyclohexadiene-1,4-dione
Benzenemethanol
Benzenemethanamine
Benzene, 1,1′-(1,2-ethanediyl)bisBicyclo[2.2.1]heptane, 1,7,7-trimethyl1-Butanol
2-Butanol
2-Propanol, 2-methyl1-Butanamine
Butanal
Butanoic acid
1-Butanone, 1-phenyl-

Elaidic acid
Elaidolinolenic acid
Ethyl alcohol*
Ethyl ether
Ethyl sulfide*
Ethylamine
Ethylene
Ethylene glycol*
Ethylene oxide*
Ethylenimine

9-Octadecenoic acid, (E)9,12,15-Octadecatrienoic acid, (E,E,E)Ethanol
Ethane, 1,1′-oxybisEthane, 1,1′-thiobis
Ethanamine
Ethene
1,2-Ethanediol
Oxirane
Aziridine

Flavan
Flavanone
Flavone
Flavylium
Fulvene*
Fumaric acid
2-Furaldehyde
Furfuryl alcohol
Furfurylamine
Furoic acid

2H-1-Benzopyran, 3,4-dihydro-2-phenyl4H-1-Benzopyran-4-one, 2,3-dihydro-2-phenyl
4H-1-Benzopyran-4-one, 2-phenyl1-Benzopyrylium, 2-phenyl1,3-Cyclopentadiene, 5-methylene2-Butenedioic acid, (E)2-Furancarboxaldehyde
2-Furanmethanol
2-Furanmethanamine
Furancarboxylic acid

Caffeine
Camphene*
Camphor*
Carane
Carbodiimide
Carbostyril
Carvacrol
Chalcone
Chroman

Gallic acid
Gentisic acid
Glutaconic acid
1H-Purine-2,6-dione,3,7-dihydro-1,3,7-trimethyl- Glutaric acid
Bicyclo[2.2.1]heptane,2,2-dimethyl-3-methylene- Glyceraldehyde
Bicyclo[2.2.1]heptan-2-one, 1,7,7-trimethyl- Glyceric acid
Bicyclo[4.1.0]heptane, 3,7,7-trimethylGlycerol*
Methanediimine
Glycidic acid
2(1H)-Quinolinone
Glycolic acid
Phenol, 2-methyl-5-(1-methylethyl)Glyoxal
2-Propen-1-one, 1,3-diphenylGlyoxylic acid
2H-1-Benzopyran, 3,4-dihydroGuanine

* Name used in 8CI for unsubstituted substance only.

Benzoic acid, 3,4,5-trihydroxyBenzoic acid, 2,5-dihydroxy2-Pentenedioic acid
Pentanedioic acid
Propanal, 2,3-dihydroxyPropanoic acid, 2,3-dihydroxy1,2,3-Propanetriol
Oxiranecarboxylic acid
Acetic acid, hydroxylEthanedial
Acetic acid, oxo6H-Purin-6-one, 2-amino-1,7-dihydro-

Organic Chemist's Desk Reference, Second Edition

Table 3.3 (continued)
8CI Name

9CI Name

8CI Name

9CI Name

Heteroxanthine
Hippuric acid
Hydantoin
Hydracrylic acid
Hydratropic acid
Hydrazobenzene
Hydrocinnamic acid
Hydrocoumarin
Hydroorotic acid
Hydroquinone
Hydrouracil
Hypoxanthine

1H-Purine-2,6-dione, 3,7-dihydro-7-methylGlycine, N-benzoyl2,4-Imidazolidinedione
Propanoic acid, 3-hydroxyBenzeneacetic acid, α-methylHydrazine, 1,2-diphenylBenzenepropanoic acid
2H-1-Benzopyran-2-one, 3,4-dihydro4-Pyrimidinecarboxylicacid,hexahydro-2,6-dioxo1,4-Benzenediol
2,4(1H,3H)-Pyrimidinedione, dihydro6H-Purin-6-one, 1,7-dihydro-

Indan
Indoline
Indone
Isobarbituric acid
Isobutyl alcohol*
Isobutyric acid*
Isocaffeine
Isocarbostyril
Isochroman
Isocoumarin
Isocytosine*
Isoflavan
Isoflavanone

2-Butenedioic acid, (Z)2,5-Furandione
1H-Pyrrole-2,5-dione
Butanedioic acid, hydroxyPropanedioic acid
Benzeneacetic acid, α-hydroxy1,3,5-Triazine-2,4,6-triamine
Cyclohexane, methyl(1-methylethyl)2-Butenedioic acid, 2-methyl-, (E)Phenol, 2,4,6-trimethylBenzene, 1,3,5-trimethyl
Propanedioic acid, oxoBenzenesulfonic acid, 3-amino2-Propenoic acid, 2-methyl
Methane, sulfinylbisMethanamine
Methanimine
Tetradecanoic acid

Isoflavone
Isoflavylium
Isoguanine
Isohexyl alcohol*
Isoindoline
Isonicotinic acid
Isonipecotic acid
Isopentyl alcohol*
Isophthalic acid
Isoprene*
Isopropyl alcohol*
Isopropylamine
Isoquinaldic acid
Isovaleric acid*

1H-Indene, 2,3-dihydro1H-Indole, 2,3-dihydro1H-Inden-1-one
2,4,5(3H)-Pyrimidinetrione, dihydro1-Propanol, 2-methylPropanoic acid, 2-methyl1H-Purine-2,6-dione,3,9-dihydro-1,3,9-trimethyl1(2H)-Isoquinolinone
1H-2-Benzopyran, 3,4-dihydro1H-2-Benzopyran-1-one
4(1H)-Pyrimidinone, 2-amino2H-1-Benzopyran, 3,4-dihydro-3-phenyl
4H-1-Benzopyran-4-one,
2,3-dihydro-3-phenyl
4H-1-Benzopyran-4-one, 3-phenyl1-Benzopyrylium, 3-phenyl2H-Purin-2-one, 6-amino-1,3-dihydro1-Pentanol, 4-methyl1H-Isoindole, 2,3-dihydro4-Pyridinecarboxylic acid
4-Piperidinecarboxylic acid
1-Butanol, 3-methyl1,3-Benzenedicarboxylic acid
1,3-Butadiene, 2-methyl2-Propanol
2-Propanamine
1-Isoquinolinecarboxylic acid
Butanoic acid, 3-methyl-

Maleic acid
Maleic anhydride
Maleimide
Malic acid
Malonic acid
Mandelic acid
Melamine
Menthane
Mesaconic acid*
Mesitol
Mesitylene
Mesoxalic acid
Metanilic acid
Methacrylic acid*
Methyl sulfoxide*
Methylamine
Methylenimine
Myristic acid*
Naphthalic acid
Naphthoic acid
Naphthol
Naphthoquinone
Naphthylamine
Nicotinic acid
Nipecotic acid
Norbornane
Norcarane
Norpinane

1,8-Naphthalenedicarboxylic acid
Naphthalenecarboxylic acid
Naphthalenol
Naphthalenedione
Naphthalenamine
3-Pyridinecarboxylic acid
3-Piperidinecarboxylic acid
Bicyclo[2.2.1]heptane
Bicyclo[4.1.0]heptane
Bicyclo[3.1.1]heptane

Oleic acid
Orotic acid
Oxalacetic acid
Oxalic acid

9-Octadecenoic acid, (Z)4-Pyrimidinecarboxylicacid,1,2,3,6-tetrahydro-2,6-.
dioxoButanedioic acid, oxoEthanedioic acid

Ketene

Ethenone

Lactic acid
Lauric acid*
Lepidine
Levulinic acid
Linoleic acid
Linolelaidic acid
Linolenic acid
γ-Linolenic acid
Lumazine
Lupetidine*
Lutidine

Propanoic acid, 2-hydroxy
Dodecanoic acid
Quinoline, 4-methylPentanoic acid, 4-oxo9,12-Octadecadienoic acid, (Z,Z)9,12-Octadecadienoic acid, (E,E)9,12,15-Octadecatrienoic acid, (Z,Z,Z)6,9,12-Octadecatrienoic acid, (Z,Z,Z)2,4(1H,3H)-Pteridinedione
Piperidine, C,C′-dimethylPyridine, dimethyl-

Palmitic acid*
Paraxanthine
Pentaerythritol*
Pentyl alcohol*
tert-Pentyl alcohol*
Peroxyacetic acid
Peroxybenzoic acid
Phenethyl alcohol
Phenethylamine
Phenetidine
Phenetole
Phenylenediamine
Phloroglucinol
Phthalan
Phthalic acid
Phthalic anhydride
Phthalide
Phthalimide
Phthalonic acid

Hexadecanoic acid
1H-Purine-2,6-dione, 3,7-dihydro-1,7-dimethyl1,3-Propanediol, 2,2-bis-(hydroxymethyl)
1-Pentanol
2-Butanol, 2-methylEthaneperoxoic acid
Benzenecarboperoxoic acid
Benzeneethanol
Benzeneethanamine
Benzenamine, ar-ethoxyBenzene, ethoxyBenzenediamine
1,3,5-Benzenetriol
Isobenzofuran, 1,3-dihydro
1,2-Benzenedicarboxylic acid
1,3-Isobenzofurandione
1(3H)-Isobenzofuranone
1H-Isoindole-1,3(2H)-dione
Benzeneacetic acid, 2-carboxy-α-oxo-

* Name used in 8CI for unsubstituted substance only.

Nomenclature Fundamentals

Table 3.3 (continued)
8CI Name

9CI Name

8CI Name

9CI Name

Phytol
Picoline
Picolinic acid
Picric acid
Pimelic acid*
Pinane
Pipecolic acid
Pipecoline
Piperonal
Piperonylic acid
Pivalic acid*
Propiolic acid
Propionaldehyde
Propionic acid
Propionitrile
Propiophenone
Propyl alcohol*
Propylamine
Propylene oxide
Protocatechuic acid
Pyridone
Pyrocatechol
o-Pyrocatechuic acid
Pyrogallol
Pyruvic acid

2-Hexadecen-1-ol, 3,7,11,15-tetramethylPyridine, methyl2-Pyridinecarboxylic acid
Phenol, 2,4,6-trinitroHeptanedioic acid
Bicyclo[3.1.1]heptane, 2,7,7-trimethyl2-Piperidinecarboxylic acid
Piperidine, C-methyl1,3-Benzodioxole-5-carboxaldehyde
1,3-Benzodioxole-5-carboxylic acid
Propanoic acid, 2,2-dimethyl2-Propynoic acid
Propanal
Propanoic acid
Propanenitrile
1-Propanone, 1-phenyl1-Propanol
1-Propanamine
Benzoic acid, 3,4-dihydroxyPyridinone
1,2-Benzenediol
Benzoic acid, 2,3-dihydroxy
1,2,3-Benzenetriol
Propanoic acid, 2-oxoOxirane, methyl-

Stilbene
Styrene
Suberic acid*
Succinic acid
Succinic anhydride
Succinimide
Sulfanilic acid

Benzene, 1,1′-(1,2-ethenediyl)bisBenzene, ethenylOctanedioic acid
Butanedioic acid
2,5-Furandione, dihydro2,5-Pyrrolidinedione
Benzenesulfonic acid, 4-amino-

Tartaric acid
Tartronic acid
Taurine
Terephthalic acid
Tetrolic acid
Theobromine
Theophylline
Thujane
Thymine
Thymol
Toluene
Toluic acid
Toluidine
Triethylamine
Trimethylamine
Trimethylene oxide*
Tropic acid*
Tropolone

Butanedioic acid, 2,3-dihydroxyPropanedioic acid, hydroxyEthanesulfonic acid, 2-amino1,4-Benzenedicarboxylic acid
2-Butynoic acid
1H-Purine-2,6-dione, 3,7-dihydro-3,7-dimethyl1H-Purine-2,6-dione, 3,7-dihydro-1,3-dimethyl
Bicyclo[3.1.0]hexane,4-methyl-1-(1-methylethyl)2,4(1H,3H)-Pyrimidinedione, 5-methylPhenol, 5-methyl-2-(1-methylethyl)Benzene, methylBenzoic acid, methylBenzenamine, ar-methylEthanamine, N,N-diethylMethanamine, N,N-dimethylOxetane
Benzeneacetic acid, α-(hydroxymethyl)2,4,6-Cycloheptatrien-1-one, 2-hydroxy-

Quinaldic acid
Quinaldine
Quinolone
Quinuclidine

2-Quinolinecarboxylic acid
Quinoline, 2-methylQuinolinone
1-Azabicyclo[2.2.2]octane

Uracil
Urete
Uretidine
Uric acid

2,4(1H,3H)-Pyrimidinedione
1,3-Diazete
1,3-Diazetidine
1H-Purine-2,6,8(3H)-trione, 7,9-dihydro-

Resorcinol
α-Resorcylic acid
β-Resorcylic acid
γ-Resorcylic acid
Ricinelaidic acid
Ricinoleic acid

1,3-Benzenediol
Benzoic acid, 3,5-dihydroxyBenzoic acid, 2,4-dihydroxyBenzoic acid, 2,6-dihydroxy9-Octadecenoic acid, 12-hydroxy-, [R-(E)]9-Octadecenoic acid, 12-hydroxy-, [R-(Z)]-

Valeric acid
Vanillic acid
Vanillin
Veratric acid
o-Veratric acid
Vinyl alcohol

Pentanoic acid
Benzoic acid, 4-hydroxy-3-methoxyBenzaldehyde, 4-hydroxy-3-methoxyBenzoic acid, 3,4-dimethoxyBenzoic acid, 2,3-dimethoxyEthenol

Salicylic acid
Sarcosine
Sebacic acid*
Sorbic acid
Stearic acid*

Benzoic acid, 2-hydroxyGlycine, N-methylDecanedioic acid
2,4-Hexadienoic acid
Octadecanoic acid

Xanthine
Xylene
Xylenol
Xylidine

1H-Purine-2,6-dione, 3,7-dihydro
Benzene, dimethylPhenol, dimethylBenzenamine, ar, ar′-dimethyl-

* Name used in 8CI for unsubstituted substance only.

3.2.2 Changes in CAS Nomenclature 1977–2006
CAS nomenclature was stable for most organics between 1977 and 2006 and the system was known
as 9CI nomenclature.
The following specialised classes of organic substances or types of names were subject to changes
during the twelfth (1987–1991) or thirteenth (1992–1996) Collective Index periods:
• Carbohydrate lactams
• Formazans
• Multiplicative names

•
•
•
•
•
•

Organic Chemist's Desk Reference, Second Edition

Nitrilimines
Onium compounds (free radicals)
Phosphonium ylides
Phosphorylhaloids and halogenoids
Zwitterions and sydnones
List of common ring systems

Further major changes to CAS nomenclature affecting organics were made in 2006 and are
described at www.cas.org.
Some examples of the 2006 changes affecting simple mainstream organics are shown here. Other
changes affecting more specialised areas of nomenclature are referred to in the following chapter.
9CI

New (2006) CAS Name

Ketones
Me3Si–COCH2CH3

Trimethyl(1-oxopropyl)silane
1-(1-Oxopropyl)piperidine

1-(Trimethylsilyl)-1-propanone
1(1-Piperidinyl)-1-propanone

N
O
Aldehydes substituted at the aldehydo hydrogen
1-Nitrosoacetaldehyde
H3CCO–NO

1-Nitrosoethanone

Silanes
PhSiMeO

Methyloxophenylsilane

(Methyloxosilyl)benzene

Acylheteroatom substances
Ph2P–COCH2CH3

(1-Oxopropyl)diphenylphosphine

1-(Diphenylphosphino)-1-propanone

Locants
In various types of compounds where
locants were previously omitted because
the name was unambiguous without them,
they are now inserted

Oxiranecarboxylic acid
Bicyclo[2.2.2]octanone
Propynoic acid
Butanedioic acid, monoethyl ester

2-Oxiranecarboxylic acid
Bicyclo[2.2.2]octan-2-one
2-Propynoic acid
Butanedioic acid, 1-ethyl ester

3.3 Types of Name
Names may be of the following types:
• Substitutive. Substitution of hydrogen, usually, by another group, e.g., chloromethane.
These names are the commonest.
• Additive. Addition of an atom or group of atoms, e.g., pyridine N-oxide, and
decahydronaphthalene
• Subtractive. Loss of certain atoms or groups from a parent structure, e.g., N-demethylnitidine.
Relatively common in natural product nomenclature, rare in mainstream organic chemistry.
• Conjunctive, e.g., cyclohexanemethanol. A conjunctive name may be applied when the
principal functional group is attached to a saturated carbon chain that is directly attached
to a cyclic component by a carbon-carbon single bond. A conjunctive name consists of the
name of the parent ring system followed by the name of the alicyclic chain plus a suffix
indicating the principal group. The ring retains its normal numbering; carbon atoms in the
side chain are indicated by Greek letters. The terminal carbon atom of acids, acid halides,
amides, aldehydes, and nitriles is not lettered. Extensively used in CAS.

Nomenclature Fundamentals
OH

α
6
5

β
1
4

7
6

2
3

cyclohexanemethanolâ•…â•…

6
7

4
1

2
3

NH2

2-naphthaleneethanamine
γ

3
2

OH
O

3-quinolinebutanoic acid
(substitutive equivalent is 4-(3-quinolinyl)butanoic acid)
5
6

4
1

3
2

Br
β

Cl
O

α-bromo-2-pyridinepropanoyl chloride
COOH
N
4-(3-quinolinyl)-2-butenoic acid

But note that in 4-(3-quinolinyl)-2-butenoic acid, the unsaturated chain means that substitutive nomenclature has to be used. Forms such as Δα,β-3-quinolinebutanoic acid are
obsolete and should not be used.
• Multiplicative, e.g., 2,2′-thiobisacetic acid, HOOCCH2-S-CH2COOH. A multiplying radical, in this case thio, is used to join two or more identical fragments. These names are fairly
extensively used in CAS, but only where the two joined fragments are completely identical,
e.g., 2,2′-oxybispyridine but not 2,3′-oxybispyridine (CAS name 2-(3-pyridinyloxy)pyridine).
• Radicofunctional, e.g., methyl alcohol, ethyl methyl ketone, dimethyl peroxide. A name in
which the principal function is expressed as a single-name term while the remainder of the
structure attached to this function is described by one or more radicals. Largely obsolescent in organic chemistry, but still extensively used in the real world. Used by CAS only
for disulfides, peroxides, and hydroperoxides.
• Replacement, e.g., azacyclotridecane. Organic replacement names are formed by denoting
heteroatoms that replace skeletal atoms of a hydrocarbon molecular skeleton by organic
replacement prefixes (Table3.4). In nomenclature, the prefixes are cited in the order they
are given in the table.
Table3.4
Organic Replacement Prefixes
fluorine
chlorine
bromine
iodine
oxygen
sulfur
selenium
tellurium
nitrogen

fluora
chlora
broma
ioda
oxa
thia
selena
tellura
aza

phosphorus
arsenic
antimony
bismuth
silicon
germanium
tin
lead
boron

phospha
arsa
stiba
bisma
sila
germa
stanna
plumba
bora

Organic Chemist's Desk Reference, Second Edition

Elision of vowels is not used in replacement nomenclature, thus pentaoxa- not pentoxa-.
Prefixes azonia, oxonia, thionia, etc., denote replacement of a carbon atom by a positively
charged atom.
Replacement names can be used for chains of atoms, usually when there are four or
more heteroatoms. They are useful for naming polyethers:

H31C–2O–CH2CH2–O–CH2CH2–O–CH2CH2–O–CH2CH2–14O–15CH3
2,5,8,11,14-pentaoxapentadecane

Replacement nomenclature is also used for some heterocyclic systems, including von
Baeyer systems (see Chapter 4), large rings (>10 members) and some spiro compounds.
NH
azacyclotridecane

Si
silabenzene

3.4 Constructing a Systematic Name
A systematic (e.g., CAS) name may have up to four components; the heading parent, the substituents, the modifications, and the stereodescriptors. Of these, only the first is always present; the
others may or may not be.

3.4.1 The Heading Parent
The heading parent, e.g., 2-butenoic acid, consists of a molecular skeleton (2-butene) and a suffix
(-oic acid) detailing the principal functional group. There can only be one functional group in any
one name.* (Note elision of the terminal -e in butene.) Where there is no functional group, the heading parent consists only of a molecular skeleton name, e.g., methane, pyridine.
The main types of molecular skeleton are the following:
• Unbranched chains of carbon atoms with or without multiple bonds, e.g., methane, propane, pentane, 1-butene, 1,3-pentadiyne.
• Rings or ring systems, e.g., cyclopentane, benzene, benzo[b]thiophene. The naming of the
different types of ring systems is covered in Chapter 4.
• Conjunctive parents.
3.4.1.1 Choosing the Heading Parent
The first step in choosing the index heading parent is to identify the principal functional group (the
term characteristic group is now preferred by IUPAC):
• If there is no functional group (alkanes, parent heterocyclic systems, etc.), just name
the skeleton.
• If there is only one functional group, this takes precedence in nomenclature and numbering.
*

Very occasional deviations from this IUPAC principle may sometimes be made for ease of nomenclature, e.g., in
the Dictionary of Natural Products for compounds containing both lactone and carboxylic acid functions, e.g.,
3,14-dihydroxycard-20(22)-enolid-19-oic acid. CAS does not do this.

Nomenclature Fundamentals

Table3.5
Functional Groups in Order of Priority
Functional Group
cations (e.g., ammonium)
carboxylic acid
sulfonic acid
carboxylic acid halide
sulfonyl halide
carboxamide
sulfonamide
nitrile
aldehyde
ketone
thione
alcohol and phenol
thiol
amine
imine
a

Suffixa

Prefixa

E.g., >N+<
–COOH
–SO3H
–COX
–SO2X
–CONH2
–SO2NH2
–CN
–CHO

-ium
-oic acid or -carboxylic acidb
-sulfonic acid
-oyl halide or -carbonyl halideb
-sulfonyl halide
-amide or -carboxamideb
-sulfonamide
-nitrile or -carbonitrileb
-al or -carboxaldehydeb

carboxy
sulfo
(haloformyl)
(halosulfonyl)
(aminocarbonyl)
(aminosulfonyl)
cyano

NH

-one
-thione
-ol
-thiol
-amine
-imine

O
S
–OH
–SH
–NH2

formyl
oxo
thioxo
hydroxy
mercapto
amino
imino

Only one type of function may be expressed as a suffix in a name. If more than one type of
functional group is present, those of lower priority are expressed using substituent prefixes.
The suffixes -oic acid, -oyl halide, -amide, -nitrile, and -al are used when the functional group
is at the end of a carbon chain, as in pentanoic acid. The endings -carboxylic acid, etc., are used
when the group is attached to a ring, as in 2-pyridinecarboxylic acid.

• If there are two or more different functional groups, consult Table3.5, and the functional
group highest in the list takes precedence. The other groups become substituents.
• If there are two or more identical functional groups, a choice of molecular skeletons is possible. The rules summarised below should give a choice, but in case of uncertainty, it is best
to locate related compounds and name by analogy.
For example, consider the compound below:

This contains two ketone groups which cannot be expressed as a single parent. The
heading parent could either be cyclohexanone or 2-propanone but the correct name is
4-(2-oxopropyl)cyclohexanone. In order to arrive at this kind of conclusion, the following
rules are applied in sequence until a decision is reached.

1. The preferred parent is that which expresses the maximum number of the principal
function groups.
O

2,4-Pentanedione (expresses two ketone groups) > cyclohexanone (expresses only one
ketone group) → 2,4-Pentanedione, 1-(4-oxocyclohexyl)-.

Organic Chemist's Desk Reference, Second Edition

2. A cyclic molecular skeleton is preferred to an acyclic carbon chain.
O

Cyclohexanone (cyclic skeleton) > 3-heptanone (acyclic skeleton) → Cyclohexanone,
4-(3-oxoheptyl)-.

3. The preferred parent is that which contains the maximum possible number of skeletal
atoms.

1-Hexene (six atoms) > 1,4-pentadiene (five atoms) → 1-Hexene, 3-ethenyl-.

4. For acyclic parents, the parent that expresses the maximum number of multiple bonds
(double or triple) is preferred.

1,4-Pentadiene (two multiple bonds) > 1-pentene (one multiple bond) → 1,4-Pentadiene,
3-ethyl-.

5. For acyclic parents with the same number of multiple bonds, double bonds are preferred to triple bonds.

1,4-Pentadiene (two double bonds) > 1-penten-4-yne (one double bond) →
1,4-Pentadiene, 3-ethynyl-.

6. The preferred parent is that which contains the lowest locants for functional groups.
OH
OH

1,2-Benzenediol (locants 1,2) > 1,3-benzenediol (locants 1,3) → 1,2-Benzenediol,
3-[(2,4-dihydroxyphenyl)methyl]-.

7. The preferred parent is that which contains the lowest locants for multiple bonds (double or triple).
HO

2-Butyn-1-ol (multiple-bond locant 2) > 3-buten-1-ol (multiple-bond locant 3) →
2-Butyn-1-ol, 4-[(4-hydroxy-1-butenyl)oxy]-.

Nomenclature Fundamentals

8. The preferred parent is that which contains the lowest locants for double bonds.
HO

OH
O

2-Penten-4-yn-1-ol (double-bond locant 2) > 4-penten-2-yn-1-ol (double-bond locant 4)
→ 2-Penten-4-yn-1-ol, 5-[(5-hydroxy-1-penten-3-ynyl)oxy]-.

9. The Index Name is based on that heading to which is attached the greatest number of
substituents.
CCl3
O2N

COOH

Propanoic acid, 3,3,3-trichloro-2-methyl-2-(nitromethyl)- (five substituents on the
propanoic acid parent) > propanoic acid, 2-methyl-3-nitro-2-(trichloromethyl)- (three
substituents attached to the parent propanoic acid) or propanoic acid, 2-(nitromethyl)2-(trichloromethyl)- (two substituents on the propanoic acid parent).

10. The Index Name is based on that parent which gives the lowest locants for substituents.
O

COOH

HOOC

Benzoic acid, 3-(4-carboxyphenoxy)- (substituent at the 3 position on the parent benzoic acid) > benzoic acid, 4-(3-carboxyphenoxy)- (substituents at the 4 position).

11. If no decision has been made at this point, a multiplicative name may be possible (see
Section 3.3).
H
N

Ethanol, 2,2′-iminobis-.

12. If no decision can be made at this point, the CA Index Name will appear first in the CA
Substance Index.
F
F3C

CCl3
COOH

Propanoic acid, 2,3,3,3-tetrafluoro-2-(trichloromethyl)- > propanoic acid, 3,3,3-trichloro-2-fluoro-2-(trifluoromethyl)- because it would appear first alphabetically in the
CA Substance Index (tetrafluoro comes before trichloro).

3.4.2 Functional Groups
If more than one type of functional group is present, the one highest in the list is treated as the principal functional group (Table3.5). Some groups can never be functional groups, only substituents,
e.g., chloro-, nitro- (distinct from the very early literature where nitro, for example, was treated as
a functional group).

Organic Chemist's Desk Reference, Second Edition

Fully substitutive names for certain types of compounds, especially heterocyclic, also occur.
Examples are 2-aminopyridine for 2-pyridinamine, 2-formylpyridine for 2-pyridinecarboxaldehyde,
and 2-cyanopyridine for 2-pyridinecarbonitrile. Such forms are technically incorrect, but frequently
occur. Others, such as 2-carboxypyridine for 2-pyridinecarboxylic acid, are sometimes encountered
but should not be used.

3.4.3 Functional Replacement Nomenclature
This occurs when one or more oxygen atoms in a functional group are notionally replaced by
other heteroatoms. Depending on the hierarchy, this may lead to the use of functional replacement
prefixes (e.g., seleno in selenoacetic acid, H3C–C(Se)OH), infixes, or suffixes (e.g., in benzenecarbodithioic acid, Ph–C(S)–SH).
Because of the large number of possible functional groups thus generated, IUPAC guidance is
incomplete, and there is also considerable duplication of possible names, e.g., –CHSe is selenoformyl or selenoxomethyl. Table3.6 gives a list of common replacement suffixes.

Table3.6
Common Functional Replacement Suffixes
-aldehydic acid
-azonic acid
-carbodithioic acid
-carbohydrazonic acid
-carbohydroxamic acid
-carbohydroximic acid
-carbonitrile
-carbonitrolic acid
-carbonitrosolic acid
-carboperoxoic acid
-carboselenaldehyde
-carboselenoic acid
-carboselenothioic acid
-carbothioaldehyde
-carbothioamide
-carbothioic acid
-carboxamide
-carboxamidine
-carboxamidoxime
-carboxamidrazone
-carboxanilide
-carboximidamide
-carboximidic acid
-hydrazonic acid
-hydroxamic acid
-hydroximic acid
-imidic acid
-nitrolic acid
-nitrosolic acid

Denotes that one COOH group of a trivially named dicarboxylic acid has been
replaced by a CHO group; thus, malonaldehydic acid is OHCCH2COOH
R2N(O)OH
–C(S)SH
–C(OH)NNH2
–C(NOH)OH
–C(O)NHOH
–C≡N
–C(NOH)NO2
–C(NOH)NO
–C(O)OOH
–C(Se)H
–C(Se)OH or –C(O)SeH
–C(Se)SH or –C(S)SeH
–C(S)H
–C(S)NH2
–C(S)OH (-carbothioic O-acid) or –C(O)SH (-carbothioic S-acid)
–CONH2
–C(NH)NH2
–C(NOH)NH2
–C(NHNH2) NH2
–CONHPh
–C(NH)NH2
–C(NH)OH
–C(NNH2)OH
–C(O)NHOH
–C(NOH)OH
–C(NH)OH
–C(NOH)NO2
–C(NOH)NO

Nomenclature Fundamentals

Table3.6 (continued)
Common Functional Replacement Suffixes
-peroxoic acid
-selenal
-selenamide

Suffix denoting –C(O)OOH as part of an aliphatic chain; thus, propaneperoxoic
acid is H3CCH2C(O)OOH
–C(Se)H
–SeNH2

-selenenic acid
-seleninamide
-seleninic acid
-selenonamide
-selenonic acid
-sulfenamide

–SeOH; selenium analogues of sulfenic acids
–Se(O)NH2
–Se(O)OH; selenium analogues of sulfinic acids
–Se(O)2NH2
–Se(O)2OH; selenium analogues of sulfonic acids
–SNH2; thus, ethanesulfenamide is EtSNH2

-sulfenic acid
-sulfinamide
-sulfinamidine
-sulfinic acid
-sulfinimidic acid
-sulfinohydrazonic acid
-sulfinohydroximic acid
-sulfonamide
-sulfonic acid
-sulfonimidic acid
-sulfonohydrazide
-sulfonohydrazonic acid
-sulfonohydroximic acid
-tellurenamide
-tellurenic acid
-tellurinamide
-tellurinic acid
-telluronamide
-telluronic acid
-thioamide
-thioic acid

–S–OH
–S(O)NH2
–S(NH)NH2
–S(O)OH
–S(NH)OH
–S(OH)NNH2
–S(OH)NOH
–SO2NH2
–S(O)2OH
–S(O)(OH)NH
–SO2NHNH2
–S(O)(OH)NNH2
–S(O)(OH)NOH
–TeNH2
–TeOH
–Te(O)NH2
–Te(O)OH
–Te(O)2NH2
–Te(O)2OH
–C(S)NH2 at the end of an aliphatic chain
–C(S)OH (-thioic O-acid) or –C(O)SH (-thioic S-acid) at the end of an aliphatic
chain; -dithioic acid denotes –C(S)SH

3.4.4 Substituents
Groups that are not the functional group become substituents (Table3.7). In 3-amino-2-chloro-2butenoic acid, the –COOH group is the principal functional group and the –Cl and –NH2 groups are
substituents. If the carboxylic group were not present, the amino group would become the principal
functional group and the compound would be a chlorobutenamine. (The –Cl group can never be
a functional group.)
Substituents marked with an asterisk should not be used in constructing formal names, either
because they are definitely obsolete or because they are informal descriptors often used in free text
but not approved for constructing actual names (e.g., aryl, brosyl). Apart from these, the list does not
give a definite preference for one alternative over another, except in a few cases (e.g., caproyl), which
should definitely be avoided because of inaccuracy or ambiguity. Different publications, including
CAS, have different editorial preferences.
In the CAS indexes, substituents follow a dash and a comma of inversion.

Organic Chemist's Desk Reference, Second Edition

Table3.7
Substituents
Acetamido
Acetimido
Acetimidoyl
Acetoacetyl
Acetohydrazonoyl
Acetohydroximoyl
Acetonyl*
Acetoxy
Acetyl
aci-Nitr(o)amino
aci-Nitro
Acryl(o)yl*
Acyl*

Adipoyl*
Allophanyl*
Allyl
β-Allyl*
Allylidene*
Amidino/guanyl/carbamimidoyl
Amido
Aminosulfinyl
Aminosulfonyl/sulfamoyl/
sulfurimidoyl
Aminothio/aminosulfanyl

(Acetylamino) H3CCONH–
This radical name has been used both for (acetylimino) AcN and for
(1-iminoethyl) H3CC(NH)–
(1-Iminoethyl) H3CC(NH)–
(1,3-Dioxobutyl) H3CCOCH2CO–
H3CC(NHNH2)–
H3CC(NHOH)–
(2-Oxopropyl) H3CCOCH2–
(Acetyloxy) H3CCOO–
H3CCO–; often abbreviated to Ac in structural and line formulae
HON(O)N–
HON(O) (methyl-aci-nitro) is MeON(O); aci-nitro compounds are also
known as nitronic acids
(1-Oxo-2-propenyl) H2CCHCO–
General term for a radical formed from an acid by removal of a hydroxy group,
e.g., H3CCO–, PhSO2–; names for acyl radicals are derived by changing the
endings: -ic acid to -yl, -oic acid to -oyl, and -carboxylic acid to -carbonyl
Hexanedioyl, –CO–(CH2)4–CO–
H2NCONHCO–
2-Propenyl H2CCCH2
(1-Methylethenyl) H2CC(CH3)–
2-Propenylidene H2CCHCH
HNC(NH2)–
Denotes a radical formed by loss of a hydrogen from an amide group; thus,
acetamido is H3CCONH–
H2NSO– (not sulfinamoyl)
H2NSO2–
H2NS–

Amin(o)oxy
Amyl*
tert-Amyl*

H2N–O–
Pentyl H3C(CH2)4–
(1,1-Dimethylpropyl) H3CCH2C(CH3)2–

Angeloyl
Anilino
Anisoyl*

(Z)-(2-Methyl-1-oxo-2-butenyl), (Z)-H3CCHC(CH3)CO–; the (E)-form is tigloyl
(Phenylamino) PhNH–
(Methoxybenzoyl) thus, o-anisoyl is 2-MeOC6H4CO–
(2-Aminobenzoyl)-2-H2NC6H4CO–
(Anthracenylcarbonyl) (C14H9)CO–
Anthracenyl (C14H9)–
Anthracenediyl –(C14H8)–
A general name for a radical comprising an aryl group attached to an alkyl
radical, e.g., PhCH2CH2–
General term for a monovalent radical derived by loss of hydrogen from an
aromatic hydrocarbon
General term for a divalent radical derived by loss of hydrogens from two different
atoms of an aromatic hydrocarbon
N3–

Anthran(il)oyl*
Anthroyl*
Anthryl
Anthrylene
Aralkyl*
Aryl*
Arylene*
Azido
Azimino

–NNNH–; used as a bridge name in naming bridged fused ring systems

* Substituents not to be used in constructing formal names.

Nomenclature Fundamentals

Table3.7 (continued)
Substituents
Azinico/hydroxyazonoyl/
hydroxyazinylidene/
hydroxynitroroyl
Azino/hydrazinediylidene
Azinoyl/azinyl/dihydronitroryl

HO–N(O)(S)–

Azinylidene/azonoyl/hydronitroroyl
Azo/diazenediyl
Azono
Azonoyl/azinylidene/hydronitroryl
Azoxy
Benzal
Benzamido/benzoylamino/
benzenecarbonylamino
Benzenesulfenamido/(phenylthio)
amino
Benzenesulfinyl/phenylsulfinyl
Benzenesulfonamido/
benzenesulfonylamino/
(phenylsulfonyl)amino
Benzenesulfony/phenylsulfonyl
Benzhydryl*
Benzhydrylidene/
diphenylmethylidene/
diphenylmethylene*
Benzimidoyl/benzenecarboximidoyl
Benzohydroximoyl/
benzenecarbohydroximoyl
Benzoyl/phenylcarbonyl/
bezenecarbonyl
Benzyl
Benzylidene
Benzylidyne
Benzyloxy/phenylmethoxy
Boranediyl
Boranetriyl
Boryl
Borylene/boranylidene
Borylidyne

HN(O)< or HN(O)
–NN–
(HO)2N(O)–

Bromonio
Bromonium
Brosyl*
Butyryl*
sec-Butyl*
tert-Butyl

N–N
H2N(O)–

HN(O)< or –NN(O)
–NN(O)–
(Phenylmethylene) PhCH
PhCONH–
Ph–S–NH–
PhSO–
PhSO2NH–

PhSO2–
(Diphenylmethyl) Ph2CH–
Ph2C

PhC(NH)–
PhC(NOH)–
Ph–CO–
(Phenylmethyl) PhCH2–
(Phenylmethylene) PhCH
(Phenylmethylidyne) PhC
PhCH2O–
BH<
–B<
H2B–
HB
B≡, –B< or, –B; the three possibilities are more accurately described as
boranylidyne, boranetriyl, and boranylylidene, respectively
H+Br–
H2Br+–
p-Bromobenzenesulfonyl
(1-Oxobutyl) H3CCH2CH2CO–
(1-Methylpropyl) H3CCH2CH(CH3)–; often abbreviated to Bus or s-Bu in
structural formula
(1,1-Dimethylethyl) (H3C)3C–; often abbreviated to But or t-Bu in structural
formula
(continued on next page)

* Substituents not to be used in constructing formal names.

Organic Chemist's Desk Reference, Second Edition

Table3.7 (continued)
Substituents
Caprinoyl*
Caproyl*
Capryl*

Capryl(o)yl*
Carbamido
Carbam(o)yl
Carbaniloyl
Carbazimidoyl/
hydrazinecarboximidoyl
Carbazono/2diazenecarbonylhydrazinyl
Carbazoyl/hydrazinecarbonyl/
hydrazinylcarbonyl
Carb(o)ethoxy/ethoxycarbonyl
Carbobenzoxy/
phenylmethoxycarbonyl
Carbomethoxy/methoxycarbonyl
Carbonimidoyl/iminomethylene
Carbonothioyl/thiocarbonyl
Carbonyl
Cathyl*
Cetyl*

Decanoyl; definitely avoid; strong possibilities for confusion with hexanoyl or
octanoyl; see below
Hexanoyl; definitely avoid; see below
Decanoyl; definitely avoid; the derived acyl group becomes caproyl, which is
identical with the obsolete name for hexanoyl above (caprinoyl was used
instead); in addition, capryl was sometimes used in the old literature for octyl
Octanoyl; definitely avoid; see above
[(Aminocarbonyl)amino] H2NCONH–
(Aminocarbonyl) H2NCO–
[(Phenylamino)carbonyl] PhNHCO–
H2NNHC(NH)–
HNNCONHNH–
H2NNHCO–
EtOOC–
PhCH2OOC–
MeOOC–

CNH or >C(NH); the two possibilities can be systematically distinguished
as iminomethylidene and iminomethanediyl, respectively
>C(S)
>CO
(Ethoxycarbonyl) EtOC(O)–
Hexadecyl H3C(CH2)15–

Chlorocarbonyl/carbonochloridoyl/
chloroformyl
Chlorosyl
Chloryl
Cinnamoyl
Cinnamyl*

ClCO–

Cinnamylidene*
Cresoxy*
Cresyl*
Croton(o)yl*

(3-Phenyl-2-propenylidene) PhCHCHCH
(Methylphenoxy) H3CC6H4O–
(Methylphenyl) H3CC6H4– or (hydroxymethylphenyl) HO(H3C)C6H3–

Crotyl*
Cumenyl*
Cumoyl*
Cumyl*
α-Cumyl*
Cyanato
Cyano
Dansyl*
Desyl*
Diazeno

OCl–
O2Cl–
(1-Oxo-3-phenyl-2-propenyl) PhCHCHCO–; usually refers to the E-form
(3-Phenyl-2-propenyl) PhCHCHCH2–

(1-Oxo-2-butenyl) H3CCHCHCO–
2-Butenyl H3CCHCHCH2–
Isopropylphenyl (H3C)2CHC6H4–
4-Isopropylbenzoyl 4-(H3C)2CHC6H4CO–
Isopropylphenyl (H3C)2CHC6H4
(1-Methyl-1-phenylethyl) PhC(CH3)2–
NCO–
NC–
[[5-(Dimethylamino)-1-naphthalenyl]sulfonyl]
(2-Oxo-1,2-diphenylethyl) PhCOCHPh–
Diazenyl HNN–

* Substituents not to be used in constructing formal names.

Nomenclature Fundamentals

Table3.7 (continued)
Substituents
Diazo

Diazoamino
Diazonio
Diphosphino/diphosphanyl
Disilanyl
Dithio/disulfanediyl
Dithiocarboxy
Dithioperoxy/thiosulfeno/disulfanyl
Dithiosulfonyl/sulfonodithioyl
Duryl*
Durylene*
Enanth(o)yl*
Epidioxy
Epidithio
Epimino
Epithio
Epox(y)imino
Epoxymethano
Epoxythio
1,2-Ethanediyl
Ethano
Ethenyl/vinyl

N2; thus, diazomethane is H2CN2; diazo compounds are compounds containing
the diazo group, R2CN2; the term diazo has also been used in naming
compounds RNNX; for example, benzenediazohydroxide is PhNNOH,
benzenediazocyanide is PhNNCN, and benzenediazosulfonic acid is
PhNNSO3H
–NNNH–
N2+–
H2PPH–
H3Si–SiH2–
–S–S–
HSC(S)–
HS–S–
–S(S)2–
(2,3,5,6-Tetramethylphenyl)
(2,3,5,6-Tetramethyl-1,4-benzenediyl)
(1-Oxoheptyl) H3C(CH2)5CO–
–O–O– (connecting two atoms in the same ring or chain)
–S–S– (bridge)
–NH– (bridge)
–S– (bridge)
–O–NH– (bridge)
–O–CH2– (bridge)
–O–S– (bridge)
–CH2CH2–; also called ethano when a bridge
–CH2CH2– (bridge)
H2CCH–

Ethenylidene/vinylidene
Ethoxy
Ethoxycarbonyl
Ethyl
Ethylenebis(oxy)
Ethylenedioxy

H2CC
EtO–
EtO2C–
H3CCH2–; often abbreviated as Et in structural and line formulae
–OCH2CH2O–
–CH2CH2–O–O–

Ethylidene/ethnylidene

H3CCH

Ethylidyne
Ethylthio
Ethynyl
Fluoryl
Formamido/formylamino
1-Formazanyl (hydrazonomethyl)azo
or (diazanylidenemethyl)diazenyl
3-Formazanyl
5-Formazanyl (diazanylmethylene)
hydrazinyl
Formazyl
Formimidoyl

H3CCH
EtS–
HC≡C–
O2F–
HCONH–
H2NNCHNN–
(Diazenehydrazono)methyl H2NNC(NNH)–
HNNCHNNH–
[(Phenylazo)(phenylhydrazonyl)methyl] PhNNC(NNHPh)–
(Iminomethyl) HNCH–
(continued on next page)

* Substituents not to be used in constructing formal names.

Organic Chemist's Desk Reference, Second Edition

Table3.7 (continued)
Substituents
Forminato*
Formyl/methanoyl

Formyloxy
Fumar(o)yl*
Furfuryl*
Furfurylidene*
Furoyl*
Furyl*
Galloyl*
Gentisoyl*
Germyl
Germylene
Glutar(o)yl
Glyceroyl*
Glyceryl*
Glycidyl*
Glyco(l)loyl/glyco(l)lyl*
Glycyl*
Glyoxal(in)yl*
Glyoxyl(o)yl*
Guanidino/amidinoamino/
carbamidoylamino/
aminoiminomethyl (CAS)
Guanyl
Hal(gen)o*
Hippur(o)yl*
Homoallyl*
Hydantoyl*
Hydrazino/hydrazinyl/diazanyl
Hydrazono/hydrazinylidene
Hydrocinnamoyl*
Hydrocinnamyl*
Hydrohydroxynitroroyl/
hydroxyazin(o)yl
Hydroperoxy
Hydroperoxycarbonyl/peroxycarboxy
Hydroseleno
Hydrox(y)amino
Hydrox(y)imino
Hydrox(y)
iminomethyl/Chydroxycarbonimidoyl
Hydroxyphosphinidine

–CNO
–CHO; sometimes used as a substituent in fully substitutive names for
aldehydes, e.g., 2-formylpyridine (technically incorrect) 
2-pyridinecarboxaldehyde
–O–CHO
(E)-(1,4-Dioxo-2-butene-1,4-diyl) –COCHCHCO–; the (Z)-form is maleoyl
(2-Furanylmethyl)
(2-Furanylmethylene)
(Furanylcarbonyl)
A contracted form of furanyl
(3,4,5-Trihydroxybenzoyl) 3,4,5-(HO)3C6H2CO–
(2,5-Dihydroxybenzoyl) 2,5-(HO)2C6H3CO–
H3Ge
H2Ge< or H2Ge. These can be distinguished by the more formal names germanediyl
and germanylidene, respectively
(1,5-Dioxo-1,5-pentanediyl) –CO(CH2)3CO–
(2,3-Dihydroxy-1-oxopropyl) HOCH2CH(OH)CO–
1,2,3-Propanetriyl –CH(CH2–)2
Oxiranylmethyl
(Hydroxyacetoxy) HOCH2CO–
(Aminoacetyl) H2NCH2CO–
Imidazolyl
(Oxoacetyl) OHCCO–
HNC(NH2)–NH–

(Aminoiminomethyl) H2NC(NH)–
A general term for a monovalent substituent derived from a halogen atom F–,
Cl–, Br–, I–
N-Benzoylglycyl PhCONHHCH2CO–
3-Butenyl H2CCHCH2CH2–
(Carbamoylamino) acetyl or [(aminocarbonyl)amino}acetyl, H2NCONHCH2CO–
H2NNH–
H2NN
(1-Oxo-3-phenylpropyl) PhCH2CH2CO–
(3-Phenylpropyl) Ph(CH2)3–
HONH(O)–
HO–O–
HO–O–CO–
HSe–
HONH–
HONH
HNC(OH)–

>POH or POH

* Substituents not to be used in constructing formal names.

Nomenclature Fundamentals

Table3.7 (continued)
Substituents
Hydroxyphosphinyl/
hydrohydroxyphosphoryl
Hydroxysulfonothioyl/
hydroxy(thiosulfonyl)
Imidiocarbonyl/carbonimidoyl
Imidodicarbonyl/iminodicarbonyl
Iminio

–PH(O)OH

Imino

HN or HN<; the two types can more accurately be described as azanylidene and
azanediyl, respectively
HNC(NH)< or HNC; the two types can more accurately be described as
iminomethanediyl and iminomethylidene, respectively
A contracted form of indolyl
HI+–
H2I+–
OI–
O2I–

Iminomethylene
Indyl
Iodonio
Iodonium
Iodoso/iodosyl
Iodoxy/iodyl
Isoallyl*
Isoamyl*
Isobutenyl*
Isobutoxy*
Isobutyl*

Isobutylidene*
Isobutyryl*
Isocarbazido/isocarbonohydrazido
Isocrotyl*
Isocyanato
Isocyano
Isohexyl*
Isoleucyl
Isonicotinoyl*
Isonitro
Isonitroso(hydroxyimino)
Isopentenyl*
Isopentyl*
Isopentylidene*
Isophthaloyl*
Isopropenyl*
Isopropoxy
Isopropyl

HO–S(O)(S)–
–C(NH)–
–CONHCO–
H2N+

1-Propenyl H3CCHCH–
(3-Methylbutyl) (H3C)2CHCH2CH2– (in the old literature, usually italicised as
iso-amyl, so indexes under a)
2-Methyl-1-propenyl, (H3C)2CCH–
(2-Methylpropoxy) (H3C)2CHCH2O–
(2-Methylpropyl) (H3C)2CHCH2–; often abbreviated to Bui or i-Bu in structural
and line formulae; in the old literature, usually italicised as iso-butyl, so indexes
under b
(2-Methylpropylidene) (H3C)2CHCH–
(2-Methyl-1-oxopropyl) (H3C)2CHCO–
H2NC(OH)NHNH–
(2-Methyl-1-propenyl) (H3C)2CCH–
OCN–
CN–
(4-Methylpentyl) (H3C)2CH(CH2)3–
H3CCH(CH3)CH(NH2)CO–; the acyl radical from isoleucine used in naming
peptides
(4-Pyridinylcarbonyl)
aci-Nitro HON(O)
HON; isonitroso compounds is an obsolete term for oximes
3-Methyl-2-butenyl; definitely avoid; use either the systematic form or, for
brevity, the trivial prefix name prenyl
(3-Methylbutyl) (H3C)2CHCH2CH2– (in the old literature, usually italicised as
isopentyl, so indexes under p)
(3-Methylbutylidene) (H3C)2CHCH2CH
1,2-Phenylenedicarbonyl 1,3-C6H4(CO–)2
(1-Methylethenyl) H2CC(CH3)–
(1-Methylethoxy) (H3C)2CHO–
(1-Methylethyl) (H3C)2CH– (in the old literature, usually italicised as isopropyl,
so indexes under p)
(continued on next page)

* Substituents not to be used in constructing formal names.

Organic Chemist's Desk Reference, Second Edition

Table3.7 (continued)
Substituents
Isopropylidene
Isoselenocyanato
Isosemicarbazido
Isothiocyanato
1-Isoureido*
3-Isoureido*
Isovaleryl*
Isovalyl
Lactoyl*
Lauroyl*
Lauryl*
L(a)evulinoyl*
Maleoyl*
Maleyl*
Malon(o)yl*
Maloyl*
Mandeloyl*
Mercapto/sulfanyl
Mercaptocarbonyl/sulfanylcarbonyl
Mercaptooxy/sulfanyloxy
Mercaptophosphinyl/
hydromercaptophosphoryl/
mercaptooxophosphoranyl
Mercaptosulfonyl
Mesaconoyl*
Mesidino*
Mesityl*
α-Mesityl*
Mesoxalo*/carboxyoxoacetyl
Mesoxyalyl*
Mesyl
Metanilyl*
Methacryloyl*

(1-Methylethylidene) (H3C)2C
SeCN–
HNC(OH)NHNH–
SCN–
[(Iminohydroxymethyl)amino] HNC(OH)NH–
[(Aminohydroxymethylene)amino] H2NC(OH)N–
(3-Methyl-1-oxobutyl) (H3C)2CHCH2CO–
H3CCH2C(CH3)(NH2)CO–; the acyl radical from isovaline used in naming
peptides
(2-Hydroxy-1-oxopropyl) H3CCH(OH)CO–
(1-Oxododecyl) H3C(CH2)10CO–
Dodecyl H3C(CH2)11
(1,4-Dioxopentyl) H3CCOCH2CH2CO–
(Z)-(1,4-Dioxo-2-butene-1,4-diyl) –COCHCHCO–; the E-form is fumaroyl
(Z)-(3-Carboxy-1-oxo-2-propenyl) HOOCCHCHCO–
(1,3-Dioxo-1,3-propanediyl) –COCH2CO–
(2-Hydroxy-1,4-dioxo-1,4-butanediyl) –COCH2CH(OH)CO–
(Hydroxyphenylacetyl) PhCH(OH)CO–
–SH
HS–CO–
HS(O)–
HS–PH(O)–

HS–SO2–
E-[2-Methyl-1,4-dioxo-2-butene-1,4-diyl] –COCHC(CH3)CO–; the Z-form is
citraconyl
[(2,4,6-Trimethylphenyl)amino] 2,4,6-(H3C)3C6H2NH–
(2,4,6-Trimethylphenyl) 2,4,6-(H3C)3C6H2–
[(3,5-Dimethylphenyl)methyl] 3,5-(H3C)2C6H3CH2–
HOOCCOCO–
(1,2,3-Trioxo-1,3-propanediyl) –COCOCO–
Methanesulfonyl MeSO2–
[(3-Aminophenyl)sulfonyl] 3-H2NC6H4SO2–
(2-Methyl-1-oxo-2-propenyl) H2CC(CH3)CO–

Methallyl*
Methanediylidene
Methanesulfinyl
Methanesulfonamido
Methanetetrayl
Methanetriyl
Methano
Methanylylidene
Methenyl*
Methoxalyl*
Methoxycarbonyl

(2-Methyl-2-propenyl) H2CC(CH3)CH2–
C
Me–SO–
(Methylsulfonyl)amino MeSO2NH–
>C<
–CH<
–CH2– (bridge)

Methoxythio

MeO–S–

–CH
Methylidyne HC≡
Methoxyoxoacetyl or (methoxycarbonyl)acetyl MeOCO–CO–
MeO2C–

* Substituents not to be used in constructing formal names.

Nomenclature Fundamentals

Table3.7 (continued)
Substituents
Methyl
Methyldioxy/methylperoxy
Methyldithio/methyldisulfanyl
Methylene

Methylenedioxy/methylenebis(oxy)
Methylidene
Methylidyne
Methylol*
Methylthio/methylsulfanyl
Methyltrithio/methyltrisulfanyl
Morpholino
Myristoyl*
Myristyl*
Naphthenyl*
Naphthionyl*
Naphthobenzyl*
Naphthoxy
Naphthoyl
Naphthyl
Naphthylene
Nazyl*
Neopentyl*
Neophyl*
Nicotinoyl*
Nitramino
Nitrilio
Nitrilo

aci-Nitro
Nitroryl
Nitros(o)amino
Nitros(o)imino
Nitroso
Norbornyl*
Norcaryl*
Norleucyl*

Norpinyl*
Nosyl*
tert-Octyl*
Oenanthyl*
Oleoyl*

H3C–; often denoted by Me in structural and line formulae
Me–O–O–
Me–S–S–

–CH2– or CH2; the former is more correctly called methanediyl and the latter
methylidene, although methylene remains in widespread use for both; compounds
containing two CH2 groups should be called bis(methylene) not dimethylene
–O–CH2–O–

Methylene H2C or –CH2–
HC≡
(Hydroxymethyl) HOCH2–
Me–S–
Me–S–S–S–
4-Morpholinyl
(1-Oxotetradecyl) H3C(CH2)12CO–
Tetradecyl H3C(CH2)13–
(Naphthalenylmethylidyne) (C10H7)C≡
[(4-Amino-1-naphthalenyl)sulfonyl] 4,1-H2NC10H7SO2–
(Naphthalenylmethyl) (C10H7)CH2–
(Naphthalenyloxy) (C10H7)O–
(Naphthalenylcarbonyl) (C10H7)CO–
Contracted form of naphthalenyl
Naphthalenediyl
(Naphthalenylmethyl) (C10H7)CH2–
(2,2-Dimethylpropyl) (H3C)3CCH2–
2-Methyl-2-phenylpropyl PhC(CH3)2CH2–
(3-Pyridinylcarbonyl)
(Nitroamino) O2NNH–
HN+≡
≡N or –N or –N<; the three types can be distinguished using the more precise
prefixes azanylidyne, azanylylidene, and azanetriyl, respectively, but these are
not yet widely used
HON(O)
≡NO
ON–NH–
ON–N
ON–; nitroso compounds are compounds RNO
A contracted form of norbornanyl, the radical derived from norbornane
A contracted form of norcaranyl, the radical derived from norcarane
H3C(CH2)3CH(NH2)CO–; the acyl radical from norleucine used in naming
peptides; in this case the prefix nor means normal, i.e., the straight-chain isomer
of leucine
A contracted form of norpinanyl, the radical derived from norpinane
[(4-Nitrophenyl)sulfonyl] 4-O2NC6H4SO2–
(1,1,3,3-Tetramethylbutyl) (H3C)3CCH2C(CH3)2–
See enanthoyl
(1-Oxo-9-octadecenoyl) H3C(CH2)7CHCH(CH2)7CO–
(continued on next page)

* Substituents not to be used in constructing formal names.

Organic Chemist's Desk Reference, Second Edition

Table3.7 (continued)
Substituents
Oleyl*
Oxalaceto*
Oxal(o)acetyl*
Oxalo*
Oxal(o)yl*
Oxam(o)yl*
Oximido
Oxonio
Oxy
Palmitoyl*
Pelargon(o)y*
tert-Pentyl*
Perchloryl
Peroxy/dioxy
Phenacyl*
Phenacylidene*
Phenenyl*
Phenethyl*
Phenethylidene*
Phenoxy
Phenylazo/phenyldiazenyl/
benzeneazo
Phenylene
Phosphanediyl/phosphinediyl
Phosphazo
Phosphinico/hydroxyphosphoryl/
hydroxyphosphinylidene
Phosphinidene/phosphanylidene
Phosphinidyne
Phosphinim(ido)yl
Phosphino/phosphanyl
Phosphinothioyl/
dihydrophosphorothioyl/
thiophosphinoyl
Phosphinoyl/phosphinyl/
dihydrophosphoryl
Phosphinylidene/phosphonoyl/
hydrophosphoryl
Phospho

Phosphonio
Phosphonitridyl
Phosphono

(Z)-9-Octadecenyl H3C(CH2)7CHCH(CH2)8–
(3-Carboxy-1,3-dioxopropyl) HOOCCOCH2CO–
(1,2,4-Trioxo-1,4-butanediyl) –COCH2COCO–
(Carboxycarbonyl) HOOCCO–
(1,2-Dioxo-1,2-ethanediyl) –COCO–
(Aminooxoacetyl) H2NCOCO–
(Hydroxyimino) HON
H2O+–
–O–
(1-Oxohexadecyl) H3C(CH2)14CO–
(1-Oxononyl) H3C(CH2)7CO–
(1,1-Dimethylpropyl) H3CCH2C(CH3)2–
O3Cl–
–O–O–
(2-Oxo-2-phenylethyl) PhCOCH2–
(2-Oxo-2-phenylethylidene) PhCOCH
Benzenetriyl; as-phenenyl is 1,2,4-benzenetriyl, s-phenenyl is 1,3,5-benzenetriyl,
and vic-phenenyl is 1,2,3-benzenetriyl
(2-Phenylethyl) PhCH2CH2–
(2-Phenylethylidene) PhCH2CH
PhO–
Ph–NN–
–(C6H4)–; aso called benzenediyl; thus, o-phenylene or 1,2-phenylene is
1,2-benzenediyl
HP<
–PN–
HOP(O)<
HP
P≡
H2P(NH)–
H2P–; the name phosphinyl would logically be used for this radical, but
phosphinyl is well-established for H2P(O)–
H2P(S)–

H2P(O)–
HP(O) or HP(O)<
O2P–; phospho is occasionally used in place of phosphono to denote the group
–P(O)(OH)2 when attached to atoms other than C, e.g., as in phosphocholine,
Me3N+CH2CH2OP(O)(OH)2
H3P+–
H2P(≡N)–
(HO)2P(O)–

* Substituents not to be used in constructing formal names.

Nomenclature Fundamentals

Table3.7 (continued)
Substituents
Phosphonoyl/phosphinylidene/
hydrophosphoryl
Phosphoranyl/λ5-phosphanyl
Phosphoranylidene
Phosphoranylidyne
Phosphoro
Phosphorodiamidothioyl/
diaminophosphinothioyl
Phosphoroso
Phosphoryl/phosphinylidyne
Phthalimido
Phthaloyl
Phthalyl
Picolinoyl*
Picryl*
Pimeloyl*
Pipecol(o)yl*
Piperidino*
Piperidyl
Piperonyl*
Pipsyl*
Pivaloyl(pivalyl)*
Prenyl*
Prolyl
Propanamido/propionamido
Propano
Propargyl*
Propiol(o)yl*
Propionyl
Propoxy
Propyl or n-propyl
sec-Propyl*
Propylene
Propylidene
Prop(an)ylidyne
Pyrocatechuoyl*
Pseudo(o)allyl*
Pseudocumyl*

PH(O) or >PH(O)
H4P–
H3P
H2P≡
1,2-Diphosphophenediyl –PP–
–P(S)(NH2)2
OP–

≡P(O) or >P(O)– or P(O)–
(1,3-Dihydro-1,3-dioxo-2H-isoindol-2-yl)
(1,2-Phenylenedicarbonyl) 1,2-C6H4(CO–)2
(2-Carboxybenzoyl) 2-HOOCC6H4CO–
(2-Pyridinylcarbonyl)
(2,4,6-Trinitrophenyl) 2,4,6-(O2N)3C6H2–
(1,7-Dioxo-1,7-heptanediyl) –CO(CH2)5CO–
(2-Piperidinylcarbonyl)
1-Piperidinyl
A contracted form of piperidinyl
1,3-Benzodioxol-5-ylmethyl or 3,4-methylenedioxybenzyl
[(4-Iodophenyl)sulfonyl] 4-IC6H4SO2–
(2,2-Dimethyl-1-oxopropyl) (H3C)3CCO–
(3-Methyl-2-butenyl) (H3C)2CCHCH 2–; also called isoprenyl or
γ,γ-dimethylallyl (avoid these)
(2-Pyrrolidinylcarbonyl); the acyl radical from proline used in naming peptides
H3CCH2CONH–
–CH2CH2CH2– (bridge)
2-Propynyl HC≡CCH2–
(1-Oxo-2-propynyl) HC≡CCO–
(1-Oxopropyl) H3CCH2CO–
H3CCH2CH2O–
H3CCH2CH2–; often abbreviated to Pr (or Prn or n-Pr) in structural and line
formulae
(1-Methylethyl) or isopropyl, (H3C)2CH–
(Radical) (1-methyl-1,2-ethanediyl) –CH(CH3)CH2–
H3CCH2CH
H3CCH2C≡
(3,4-Dihydroxybenzoyl) 3,4-(HO)2C6H3CO–

Pyroglutamyl*
Pyromucyl*
Pyrr(o)yl*
Pyruvoyl*

(1-Methylethenyl) or isopropenyl H2CC(CH3)–
(Trimethylphenyl); as-pseudocumyl is 2,3,5-trimethylphenyl, s-pseudocumyl is
2,4,5-trimethylphenyl. and v-pseudocumyl is 2,3,6-trimethylphenyl
(5-Oxoprolyl)
(2-Furanylcarbonyl)
(Pyrrolylcarbonyl)
(1,2-dioxopropyl) H3CCOCO–

Quinaldoyl*

(2-Quinolinylcarbonyl)
(continued on next page)

* Substituents not to be used in constructing formal names.

Organic Chemist's Desk Reference, Second Edition

Table3.7 (continued)
Substituents
Salicyl*
Salicylidene*
Salicyloyl*
Sarcosyl*
Sebacoyl*
Seleneno
Selenienyl
Selenino
Seleninyl
Selenocyanato
Selenonio
Selenonium
Selenono
Selenonyl
Selenoxo
Selenyl/hydroseleno
Semicarbazido*
Semicarbazono*
Senecioyl*
Siamyl*
Silanediyl
Silanediylidene
Silanetetrayl
Silanylylidene
Sil(yl)oxy
Silyl
Silylene
Silylidyne
Sinapoyl*
Sorboyl*
Stannyl
Stannylene
Stearoyl*
Stearyl*
Stibyl
Stibylene

[(2-Hydroxyphenylmethyl] 2-HOC6H4CH2–
[(2-Hydroxyphenyl)methylene] 2-HOC6H4CH
(2-Hydroxybenzoyl) 2-HOC6H4CO–
(N-Methylglycyl) MeNHCH2CO–
(1,10-Dioxo-1,10-decanediyl) –CO(CH2)8CO–
HOSe–
The radical formed from selenophene by loss of a hydrogen
HOSe(O)–
OSe
NCSe–
H2Se+–
HSe+
(HO)Se(O)2–
O2Se–
Se; usually used when both free valencies are attached to the same atom
HSe–
[2-(Aminocarbonyl)hydrazino] H2NCONHNH–
2-Carbamoylhydrazono or (2-aminocarbonyl)hydrazinylidene, H2NCONHN
(3-Methyl-1-oxo-2-butenyl) (H3C)2CCHCO–
(1,2-Dimethylpropyl) (H3C)2CHCH(CH3)–
H2Si<
Si
>Si<

SiH–
H3SiO–
H3Si–
H2Si
HSi≡
[3-(4-Hydroxy-3,5-dimethoxyphenyl)-1-oxo-2-propenyl]
(1-Oxo-2,4-hexadienyl) H3CCHCHCHCHCO–
H3Sn–
H2Sn< or H2Sn; the two situations can be distinguished by the more accurate
names stannanediyl and stannylidene, respectively
(1-Oxooctadecyl) H3C(CH2)16CO–
Octadecyl H3C(CH2)17
H2Sb–

Styryl*
Suberoyl*
Succinimido*
Succin(o)yl*
Sulfamino(sulfoamino)
Sulfamoyl/sulfamyl/aminosulfonyl

HSb< or HSb; the two situations can be distinguished by the more accurate
names stibenediyl/stibanediyl and stibanylidene, respectively
(2-Phenylethenyl) PhCHCH–
(1,8-Dioxo-1,8-octanediyl) –CO(CH2)6CO–
(2,5-Dioxo-1-pyrrolidinyl)
(1,4-Dioxo-1,4-butanediyl) –COCH2CH2CO–
HOSO2NH–
–SO2NH2

Sulfanilyl*
Sulfenamoyl

[(4-Aminophenyl)sulfonyl] 4-H2NC6H4SO2–
H2N–S–

* Substituents not to be used in constructing formal names.

Nomenclature Fundamentals

Table3.7 (continued)
Substituents
Sulfeno/hydroxythio/hydroxysulfanyl
Sulfhydryl*
Sulfido
Sulfinamoyl
Sulfino
Sulfinyl
Sulfo
Sulfonio
Sulfonium
Sulfonyl
Sulfonylbis(oxy)
Sulfonyldioxy
Sulfoxonium
Sulfuryl*
Supermesityl*
Tartronoyl*
Tauryl*
Tellureno
Tellurino
Tellurono
Telluroxo
Telluryl
Terephthaloyl*
Tetramethylene*
Thenoyl*
Thenyl*
Thenylidene*
Thenylidyne*
Thexyl*
Thienyl
Thio/sulfanediyl
Thioacetyl/ethanethioyl
Thiocarbamoyl/carbamothioyl
Thiocarbonyl*
Thiocyano
Thiocyano*
Thioformyl
Thionyl*
Thiosulfeno/disulfanyl/
dithiohydroperoxy
Thiosulfinyl/thiosulfino/sulfinothioyl
Thiosulfonyl/sulfonothioyl
Thioxo/sulfanylidene
Threonyl*

HO–S–
Mercapto HS–
–S–
H2NS(O)–
HOS(O)–
OS
HO3S–
H2S+–
H3S+–
–SO2–
–O–SO2–O–
–SO2–O–O–

H3S+O
Sulfonyl –SO2–
[2,4,6-Tris (1,1-dimethylethyl)phenyl]
(2-Hydroxy-1,3-dioxo-1,3-propanediyl) –COCH(OH)CO–
[(2-Aminoethyl)sulfonyl] H2NCH2CH2SO2–
HOTe–
HOTe(O)–
HOTe(O)2–
Te; used when both free valencies are attached to the same atom
HTe–
(1,4-Phenylenedicarbonyl) 1,4-C6H4(CO–)2
1,4-Butanediyl –(CH2)4–
(Thienylcarbonyl)
(Thienylmethyl)
(Thienylmethylene)
(Thienylmethylidyne)
(1,1,2-Trimethylpropyl) (H3C)2CHC(CH3)2–
The radical derived from thiophene
–S–
Me–C(S)–
–C(S)NH2
Carbonothioyl –C(S)–
NCS–
Thiocyanato NCS–
–CH(S)
Sulfinyl –S(O)–
HS–S–
–S(S)–
–S(O)(S)–
S
H3CCH(OH)CH(NH2)CO–; the acyl radical from threonine used in naming
peptides
(continued on next page)

* Substituents not to be used in constructing formal names.

Organic Chemist's Desk Reference, Second Edition

Table3.7 (continued)
Substituents
Tigloyl*
Toloxy*
Toluidino*
Tolu(o)yl*
Tolyl*
α-Tolyl*
Tolylene*
Tosyl*
Triazano
Triazeno/azimino
Triazenyl
Triflyl*
Trimethylene/1,3-propanediyl
Trithio/trisulfanyl
Trithiosulfo/mercaptosulfonyldithio/
mercapto(dithiosulfonyl)
Trityl*

E-(2-Methyl-1-oxo-2-butenyl) (E)-H3CCHC(CH3)CO–; the Z-form is angeloyl
(Methylphenoxy) H3CC6H4O–
[(Methylphenyl)amino] H3CC6H4NH–
(Methylbenzoyl) H3CC6H4CO–
(Methylphenyl) H3CC6H4–
(Phenylmethyl) or benzyl PhCH2–
(Methylphenylene) –(H3CC6H3)–
[(4-Methylphenyl)sulfonyl] 4-H3CC6H4SO2–
–NHNHNH– (bridge)
–NN–NH– (bridge)
–NN–NH2
[(Trifluoromethyl)sulfonyl] F3CSO2–
–CH2CH2CH2–
–S–S–S–
HS–S(S)–
(Triphenylmethyl) Ph3C–
(3-Hydroxy-1-oxo-2-phenylpropyl) PhCH(CH2OH)CO–
[(Aminocarbonyl)amino] H2NCONH–
Carbonyldiimino, –NHCONH–
(1-Oxopentyl) H3C(CH2)3CO–
(H3C)2CHCH(NH2)CO; the acyl radical from valine used in naming peptides
(4-Hydroxy-3-methoxybenzoyl)
[(4-Hydroxy-3-methoxyphenyl)methyl]
(3,4-Dimethoxybenzoyl) 3,4-(MeO)2C6H4CO–
(2,3-Dimethoxybenzoyl) 2,3-(MeO)2C6H4CO–
[(3,4-Dimethoxyphenyl)methyl] 3,4-(MeO)2C6H4CH2–

Tropoyl*
Ureido*
Urylene*
Valer(o)yl*
Valyl
Vanilloyl*
Vanillyl*
Veratroyl*
o-Veratroyl*
Veratryl*
Vinyl
Vinylene*
Vinylidene/ethenylidene
Xanthyl*
Xenyl*

Ethenyl H2CCH–
1,2-Ethenediyl –CHCH–
H2CC or H2CC<; the latter better named as ethene-1,2-diyl
Contracted form of xanthenyl
-Biphenylyl PhC6H4–

Xylidino*
Xyloyl*
Xylyl*
Xylylene*

[(Dimethylphenyl)amino] (H3C)2C6H3NH–
(Dimethylbenzoyl) (H3C)2C6H3CO–
(Dimethylphenyl) (H3C)2C6H3–
[Phenylenebis(methylene)] –CH2C6H4CH2–

* Substituents not to be used in constructing formal names.

3.4.5 Modifications
If present, these modify the functional group(s), e.g., in 3-amino-2-chloro-2-butenoic acid, ethyl
ester, hydrochloride. Modifications are used for anhydrides, esters, and salts of acids, oxides, sulfides, and selenides of ring systems containing P and As, hydrazones, and oximes of carbonyl compounds, salts of amines, etc.
Note that in the case of esters, reinversion is allowed, so that, for example, the correct name for
acetic acid, ethyl ester is ethyl acetate. In CAS, esters are usually indexed at the name of the component acid. However, esters of some very common acids (class I acids) are indexed at the names

Nomenclature Fundamentals

of the component alcohol/phenol or thiol unless the alcohol/phenol or thiol component is also very
common (a class I alcohol).
Table3.8 lists the class I acids. All other acids are class II acids.
Table3.8
Class I Acids
Acetic acid
Aminobenzoic acid
(all isomers)
Benzenesulfonic acid
Benzoic acid
Boric acid (H3BO3)
Carbamic acid
Carbonic acid
Dinitrobenzoic acid
(all isomers)
Formic acid
Methanesulfonic acid
4-Methylbenzenesulfonic acid

Methylcarbamic acid
Nitric acid
Nitrobenzoic acid (all isomers)
Phenylcarbamic acid
Phosphinic acid
Phosphonic acid
Phosphoric acid
Phosphorodithioic acid
Phosphorothioic acid
Phosphorous acid
Propanoic acid
Sulfuric acid
Sulfurous acid

Table3.9 lists the class I alcohols and phenols. The list of class I thiols is completely analogous.
Table3.9
Class I Alcohols/Phenols
Benzeneethanol
Benzenemethanol
1-Butanol
2-Butanol
Chlorophenol (all isomers)
Cyclohexanol
1-Decanol
2-(Diethylamino)ethanol
2-(Dimethylamino)ethanol
1-Dodecanol
Ethanol
Ethenol
2-Ethyl-1-butanol
2-Ethyl-1-hexanol
1-Heptanol

1-Hexanol
Methanol
Methylphenol
(all isomers)
2-Methyl-1-propanol
2-Methyl-2-propanol
Nitrophenol
(all isomers)
1-Nonanol
1-Octanol
1-Pentanol
Phenol
1-Propanol
2-Propanol
2-Propen-1-ol

The combinations shown in Table3.10 occur.
Table3.10
Acid

Alcohol

Indexed at

1. Class I
2. Class I
3. Class II
4. Class II

Class I
Class II
Class I
Class II

Acid
Alcohol
Acid
Acid

Organic Chemist's Desk Reference, Second Edition

Examples of each of these combinations follow:

1. Methyl acetate is indexed at acetic acid, methyl ester.
2. Chloromethyl acetate is indexed at methanol, chloro-, acetate.
3.Methyl chloroacetate is indexed at acetic acid, chloro-, methyl ester.
4.Chloromethyl chloroacetate is indexed at acetic acid, chloro-, chloromethyl ester.

There is one exception. Where a polybasic class I acid, e.g., phosphoric acid, is esterified by two
or more different alcohols, the acid heading is always used. Thus, chloromethyl dimethyl phosphate
is indexed at phosphoric acid, chloromethyl dimethyl ester because the alcoholic components are
not alike.

3.4.6 Stereodescriptor(s)
These are dealt with in Chapter 7.

4 Nomenclature of Ring Systems
4.1 Ring Systems (General)
Various publications from the Chemical Abstracts Service can be used to find the name of a known
ring system. The most comprehensive source of ring system names is the Ring Systems Handbook
(RSH). Entries are in ring analysis order, i.e., according to the following hierarchy of ring data:

1. Number of component rings
2.Sizes of component rings
3.Elemental analysis of component rings
For example, the ring system
N
N

contains four rings, with sizes 6,6,6,7, and with elemental compositions C5N–C6 –C6 –C5NO. The
preferred parent contains the senior ring system. For ring systems, nitrogen heterocycles > other
heterocycles > carbocycles. Thus, pyridine > furan > naphthalene. If two ring systems are of a type,
then that with the greater number of individual rings is preferred, e.g., quinoline > pyridine, and
naphthalene > benzene. A further twelve criteria are needed to allow a decision to be made in all
cases. These can be found in the Chemical Abstracts Index Guide, Appendix IV, paragraph 138.
A list of common hydrocarbon and heterocyclic parent skeletons and their numbering appears
in Table 4.1.

4.1.1 Indicated Hydrogen
An italic H appearing with the name of a ring or ring system usually denotes an indicated or added
hydrogen atom. For some fused polycyclic ring systems and certain monocyclic heterocycles that
contain the maximum number of cumulative double bonds, it is possible to have more than one
isomer differing in the positions of the double bonds. They are distinguished by using H with
the appropriate locant to indicate that atom which is not connected to either neighbouring ring atom
by a double bond. The H is known as indicated hydrogen.
5
6

3
2

O
2H-pyran

5
6

1
2

3
2

O
4H-pyran

1
2
3

1H-indene

2H-indene

Indicated hydrogen has the highest priority in naming compounds.
N
HOOC

N
H

1H-imidazole-5-carboxylic acid > 3H-imidazole-4-carboxylic acid.
71

Organic Chemist's Desk Reference, Second Edition

4.1.2 Added Hydrogen
Sometimes a hydrogen atom needs to be added to a ring system in order to accommodate structural
features such as principal groups. For example, introduction of an oxo group into a naphthalene will
mean the removal of one double bond, and there will then be a CH2 unit in the ring. The position of
this CH2 unit is indicated by using H with the appropriate locant.
O

2
3

1(2H)-naphthalenone

2
3

1(4H)-naphthalenone

Table 4.1
Hydrocarbon and Heterocyclic Parent Skeletons
5
4

3 2

1
2

12
4 3

5
4

2
3

Cyclopropane Spiropentane Cyclobutane Cyclopentane
Furan

5
4

N
1

H
N

2
3

H
N

52 1 N
4
3

52 1
4
3

5
4

52 1
4
3

N
1

H
N

2
3

2H-Pyrrole
(2H-Azole)

Thiophene Pyrrole
(Azole)

52 1 S
4
3

521 N
4
3

H
N

52 1
4
3

Pyrazole
(1,2-Diazole)

3H-Pyrrole
(3H-Azole)

52 1 N
4
3

52 1 S
4
3

5 1 2
4
3

52 1 N
4
3

52 1
4
3

N
N
N
S
2H-Imidazole
Isoxazole
Thiazole
Oxazole
N
N
1,2-Dithiole 1,3-Dithiole 3H-1,2-Oxathiole
(1,3-Diazole) 1,2,3-Triazole 1,2,4-Triazole
(1,2-Oxazole) (1,3-Thiazole) (1,3-Oxazole)
S

52 1 N
4
3

Isothiazole
(1,2-Thiazole)

N
1,2,3-Oxadiazole

H
3H-1,2,3-Dioxazole
O

2H-Pyran

6
5

H
N
1

52 1 N
4
3

52 1
4
3

N
N
1,3,4-Oxadiazole

N5
4

O
N52 1 N
4
3
N
1,2,3,5-Oxatriazole

52 1 N
4
3

52 1
4
3

N
N
1,2,3,4-Oxatriazole

1 2S
3

6
5

52 1
4
3

1
4

6
5

2
3

4
N
O
O
N
S
1,2,4-Dioxazole 1,3,2-Dioxazole 1,3,4-Dioxazole 5H-1,2,5-Oxathiazole 1,3-Oxathiole Benzene Cyclohexane

6 1 2
5
3
4

6 1 2
5
3
NN4

6
5

N
1

2N
3

6
5

N
1

2N
3

6 1 2O
5
3
4

6 1 2
5
3
4 O

1,2-Dioxin

1,3-Dioxin

6 1 2
5
3
4

4H-Pyran 2H-Pyran-2-one
O
(2-Pyrone)
4H-Pyran-4-one
(4-Pyrone)

2
3

N
1,2,4-Oxadiazole 1,2,5-Oxadiazole
(Furazan)

52 1 O
4
3

6 1 2
5
3
4

5 1 2N
4
3

52 1 O
4
3

O
N52 1 N

52 1 N
4
3

6 1 2N
5
3
4

6 1 2
5
3
4 N

6
5

N
1
4

2
3

6
5

N
1
4

2N
3

Pyridazine

Pyridine

6 1 2
5
3
4 N

6
5

N
1
4

2
3

Pyrimidine

6 1 2N
5
3
4

6
5

N
1

2
3

N
Pyrazine

6 1 2
5
3
4

4
4 N
N
N
1,3,5-Triazine 1,2,4-Triazine 1,2,3-Triazine 4H-1,2-Oxazine 2H-1,3-Oxazine 6H-1,3-Oxazine 6H-1,2-Oxazine 1,4-Oxazine
(s-Triazine) (as-Triazine) (v-Triazine)
Piperazine
4

N
H

6 1 2N
5
3
4

6 1 2
5
3
4

6 1 2S
N5 4 3

O
NS
6 1 2
5

6 1 2N
5
3
4

6 1 2
5
3
4
NN

6 1 2
5
3
4

H
N

72 1
6
3
5 4

N
N
N
1,2,5-Oxathiazine 1,2,6-Oxathiazine 1,2,4-Oxadiazine 1,3,5-Oxadiazine Morpholine Azepine
2H-1,2-Oxazine
H
4H-1,4-Oxazine

Nomenclature of Ring Systems

Table 4.1 (continued)
Hydrocarbon and Heterocyclic Parent Skeletons
S

72 1
6
3
5 4

72 1 N
6
3
5 4

Oxepin

Thiepin

4H-1,2-Diazepine

1 2S
3

6
5

Benzo[c]thiophene

6
5

1 2
3

6
5

H
N

1 2
3

6
5

Indole

N
1

7
4

2O
3

7
6

1 2
3
4

7
6

1 2
3

1,8-Naphthyridine

7
6

2H-Indene
(Isoindene)

2N
3

2
3

7
6

6
5

3
2

6
7

O6
5

2O
3

7
6

2
3

7
6

1H-2,3-Benzoxazine

7
6

6
5

Isobenzofuran

N
1

7
4

6
5

2
3

7
6

H
N

1 2N
3

7
4

1
9
8

7
6

4
5

2O
4 3
1

1 2
3

2O
3

7
6

1 2N
3

7
6

1 2
3
4

7
6

1 2
3

2
3

7
6

Fluorene

1
2
5 4N 3

Indolizine

8
7

9
6

H
N
9

1 2
3

7
6

1 2
3
4

2N
3

7
6

1 2N
3

1 2
3

7
6

N
H

2N
3

2
3

7
6

O
Xanthene

2
3

6
7

N
10

Acridine

3
2

1 2
3

Quinazoline

7
6

1 2
3

2H-1,4-Benzoxazine

2
3

Anthracene

7
6

Cinnoline

2H-1,3-Benzoxazine

2H-1,2-Benzoxazine

Carbazole

Phenalene

7
6

7
4

Benzisoxazole
(Indoxazene)

7
6

Isoquinoline

Quinoline

1,6-Naphthyridine

1,5-Naphthyridine

4H-3,1-Benzoxazine

1 2
3

6
5

4H-1,4-Benzoxazine

Benzo[b]thiophene

Indazole

Cyclopenta[b]pyridine Pyrano[3,4-b]pyrrole

7
6

1 2
3

1 2O
3

7
4

Octahydronaphthalene 2H-1-Benzopyran 2H-1-Benzopyran-2-one
1,2,3,4-Tetra(Decalin)
hydronaphthalene
(2H-Chromene)
(Coumarin)
(Tetralin)

2O
3

1,7-Naphthyridine

6
5

1 2
3

Benzofuran

O
1H-2-Benzopyran-1-one 3H-2-Benzopyran-1-one
(Isochromen-3-one)
(Isocoumarin)

4H-1-Benzopyran-4-one
(Chromen-4-one)

7
6

1 2
3

7
4

6
5

1H-Indole

3H-Indole

Benzoxazole 2,1-Benzisoxazole Naphthalene

7
6

6
5

1 2
3

2
3

Indene

6
5

6
7

5
8

3 2
1

Phenanthrene

2 1
3
4 76
5

Norpinane
(Bicyclo[3.1.1]heptane)

6
3

5
4

H
N

7 8
9

7H-Purine

2
3

2H-form
Quinolizine

Note: When a nitrogen or other heteroatom is at a ring junction position, that position is included in the main numbering,
e.g., indolizine.
Note the irregular numbering of anthracene and purine.

Organic Chemist's Desk Reference, Second Edition

4.2 Bridged Ring Systems
Many bridged ring systems are named by the von Baeyer system. Von Baeyer names are used mostly
for bridged ring systems and occasionally for nonbridged ring systems. Examples of von Baeyer
names are bicyclo[3.2.1]octane and tricyclo[7.4.1.03,6]tetradecane.
Bicyclo[3.2.1]octane
Bicyclo denotes two rings and octane denotes a total of eight skeletal atoms in the ring system.
[3.2.1] gives the sizes of the three bridges connecting two bridgehead atoms.
7 1
6 5

2
8 3
4

bicyclo[3.2.1]octane

The system is numbered starting from one of the bridgeheads and numbering by the longest possible path to the second bridgehead; numbering is then continued via the longer unnumbered path
back to the first bridgehead and is completed via the third bridge.
Tricyclo[7.4.1.03,6]tetradecane
Tricyclo denotes three rings and tetradecane denotes a total of fourteen skeletal atoms in the ring
system. [7.4.1] gives the sizes of three bridges connecting two bridgehead atoms as in the previous
example; these three bridges are numbered as in the previous example. 03,6 denotes that there is a
bridge of zero atoms (i.e., a bond) between the atoms numbered 3 and 6.
11 12
10
13

2
3

Fused ring systems that have other bridges are usually named by prefixing the name of the bridge
to the name of the fused ring system. The names of hydrocarbon bridges are derived from the names
of the parent hydrocarbons by replacing the final -ane, -ene, etc., by -ano, -eno, etc. Thus, –CH2– is
methano and –CHCH– is etheno.
Names for bridges containing heteroatoms include:
–O–
–S–
–NH–
–NN–
–O–O–
–S–S–
–N
–OCH2–

Epoxy
Epithio
Imino
Azo
Epidioxy
Epidithio
Nitrilo
(Epoxymethano)

Some examples are the following:
7
6

8
5

1
4

2
3

1,4-dihydro-1,4-ethanonaphthalene

Nomenclature of Ring Systems
7

6
5

1
2
3 O

4,7-dihydro-4,7-epoxyisobenzofuran

Heterocyclic systems are named by replacement nomenclature. Unsaturation is denoted by -ene
and -yne suffixes. For more information, see Eckroth, D. R., J. Org. Chem., 32, 3312, 1967.
Some common cage structures are usually named trivially as parents. CAS names all of
these systematically.
8
7

1
6

cubane

Pentacyclo[4.2.0.0 .03,8.04,7]octane (CAS,9CI name)
2,5

1
8

2
9

7
5

3
4

adamantane
Tricyclo[3.3.1.13,7]decane (CAS,9CI name)

4.3 Spiro Compounds
Spiro[3.4]octane
This name denotes that there is one spiro atom and a total of eight atoms (from octane) in the structure. The numbers in square brackets, [3,4], show that there are three atoms linked to the spiro atom
in one ring and four atoms linked to the spiro atom in the other ring.
7 8
6 5

1
2
3

spiro[3.4]octane

Numbering starts with a ring atom next to the spiro atom and proceeds first around the smaller
ring, then through the spiro atom, and then around the second ring. Heteroatoms are denoted by
replacement nomenclature.
Dispiro[5.1.7.2]heptadecane
This name indicates that there are two spiro atoms and a total of seventeen atoms in the structure.
The numbers in square brackets, [5.1.7.2], are the numbers of skeletal atoms linked to the spiro
atoms in the same order that the numbering proceeds about the ring. Thus, 5, 1, 7, and 2 correspond
to atoms 1–5, 7, 9–15, and 16–17, respectively.
13
12

16 17
8
7

14 15

11 10

dispiro[5.1.7.2]heptadecane

Numbering starts with a ring atom next to a terminal spiro atom and proceeds around this terminal
ring so as to give the spiro atoms as low numbers as possible. Trispiro names, etc., are formed similarly.

Organic Chemist's Desk Reference, Second Edition

1,1′-Spirobiindene or 1,1′-spirobi[1H-indene]
Spirobi indicates that two similar components are joined through a spiro atom. The numbers of one
component are distinguished by primes.
4'
3'
2'

5'
6'

2
3

5
4

1.1'-spirobi[1H-indene]

Spiro[cyclopentane-1,2′-[2H]indene]
This name shows that a cyclopentane ring is joined to a 2H-indene ring through a spiro atom at the
1 position of the cycopentane and the 2 position of the indene. The numbers of the second component (indene) are distinguished by primes.
6'
5'

7'
4'

1'
3' 2'

2 3
5 4

spiro[cyclopentane-1,2'-[2H]indene

Alternatively, the term spiro may be placed between the components. Thus, cyclopentanespiro2′-indene and indene-2-spiro-1′-cyclopentane are alternative names for the above compounds.

4.4 Heterocyclic Ring Systems
Some common monocyclic hetero systems have trivial names, for example, pyridine, furan (see
Table 4.1).
Hantzsch-Widman names are used for one-ring heterocyclic systems that do not have trivial
names. The names are applied to monocyclic compounds containing one or more heteroatoms in
three- to ten-membered rings. The names are derived by combining the appropriate prefix or prefixes for the heteroatoms with a stem denoting the size of the ring (see below). The state of hydrogenation is indicated either in the stem or by the prefixes dihydro-, tetrahydro-, etc.
The prefixes are the normal replacement prefixes (see “Replacement Nomenclature,” page 50),
although elision of the final a often occurs. The prefixes are cited in the following order: fluora-,
chlora-, broma-, ioda-, oxa-, thia-, selena-, tellura-, aza-, phospha-, bora-, and mercura-. Chemical
Abstracts does not use Hantzsch-Widman names for rings containing silicon.
The stems used originally are as shown in Table4.2.
The stems for unsaturated rings imply the maximum possible number of noncumulative double bonds.
Rings with more than ten members are named by replacement nomenclature, e.g., azacycloundecane.
4
5

3
2O

3N
1 2N

1
N
N
H
S
O
H
oxireneâ•…â•… aziridineâ•…â•… 1,2-oxathiolaneâ•…â•… 1H-1,2,3-triazole

Several modifications were later made in order to avoid confusion with other compounds; for
example, phosphorine was used instead of phosphine. The modified (extended) Hantzsch-Widman
system (Pure Appl. Chem., 55, 409, 1983) uses the stems shown in Table4.3.

Nomenclature of Ring Systems

Table4.2
Original Hantzsch-Widman Stems
Rings Containing Nitrogen

Rings Containing No Nitrogen

No. of Members
in Ring

Unsaturation

Saturation

Unsaturation

Saturation

â•⁄ 3
â•⁄ 4
â•⁄ 5
â•⁄ 6
â•⁄ 7
â•⁄ 8
â•⁄ 9
10

-irine
-ete
-ole
-ine
-epine
-ocine
-onine
-ecine

-iridine
-etidine
-olidine
—
—
—
—
—

-irene
-ete
-ole
-in
-epin
-ocin
-onin
-ecin

-irane
-etane
-olane
-ane
-epane
-ocane
-onane
-ecane

Table4.3
Extended Hantzsch-Widman Stemsa
No. of Members in Ring
3
4
5
6Ab
6Bb
6Cb
7
8
9
10
a
b

Unsaturation

Saturation

-irene
-ete
-ole
-ine
-ine
-inine
-epine
-ocine
-onine
-ecine

-irane
-etane
-olane
-ane
-inane
-inane
-epane
-ocane
-onane
-ecane

The stem for the least preferred heteroatom is selected.
6A applies to rings containing O, S, Se, Te, Bi, Hg;
6B applies to rings containing N, Si, Ge, Sn, Pb;
6C applies to rings containing B, F, Cl, Br, I, P, As, Sb.

Special stems were previously used for four- and five-membered rings containing one double
bond. These stems are -etine for four-membered rings containing nitrogen, -etene for four-membered rings containing no nitrogen, -oline for five-membered rings containing nitrogen, and -olene
for five-membered rings containing no nitrogen. These stems are no longer recommended.
NH
∆2-azetine or 2-azetine

4.5 Ring Assemblies
Ring assemblies are polycyclic systems consisting of two or more identical rings or ring systems
directly joined to each other by single or double bonds. Linear assemblies joined by single bonds
are named by citing a numerical prefix (Table4.4) with the name of the ring or ring system (except
for benzene and the cycloalkanes, when the appropriate radical name is used).

Organic Chemist's Desk Reference, Second Edition

Table4.4
Prefixes Used in Naming Ring Assemblies
No. of Components

Numerical Prefixes

2
3
4
5
6
7
8
9
10
11
12
13

bi
ter
quater
quinque
sexi
septi
octi
novi
deci
undeci
dodeci
trideci
etc.

The numbering of the assembly is that of the component system. One terminal component is
assigned unprimed numbers as locants, the locants of the other components being primed serially.
4''3''
5'' 2''
6'' 1''

2'
1

4'
6' 5'

1,1'-bicyclohexyl

3'
2'

5
3
6 1 2

5'
3'
6' 1' 2'

N
H

2 3 4
5
1
N 6

2,2'-bipiperidine

1' 6'

2'''3'''
1''' 4'''
6''' 5'''

4"
3"

5" 6"
2"

3 2
5 6

2' 3'
4'
6' 5'

4,2':6',4"-terpyridine

1,1':2',1'':2'',1'''-quaterphenyl
or o-quaterphenyl

Ring assembly names are sometimes applied to ring systems joined by a double bond.

1,1'-bicyclopentylidene

∆2,2'-bi-2H-indene

4.6 Ring Fusion Names
Examples of ring fusion names are:
•
•
•
•

Naphtho[2,3-b]furan
Benzo[a]cyclopent[j]anthracene
Dibenzo[de,rst]pentaphene
Pyrido[1′,2′:1,2]imidazo[4,5-b]quinoxaline

They are derived by prefixing to the name of a component ring or ring system (the base component) designations of the other components. The prefixes are normally obtained by changing
the ending -e of the name of the ring or ring system to -o; there are exceptions, such as benzo-,

Nomenclature of Ring Systems

pyrido-, and cyclopenta-. Isomers are distinguished by lettering the peripheral sides of the base
component a, b, c, etc., beginning with a for side 1 → 2. To the letter denoting where fusion occurs
are prefixed, if necessary, the numbers of the positions of attachment of the other components. The
resulting name denotes the ring system containing the maximum number of noncumulative double
bonds. In cases where the parent ring system is unsystematically numbered, e.g., anthracene, the
fusion lettering uses the 1 → 2 face as a, then proceeds around the ring sequentially, regardless of
the unsystematic numbering.
Benzo- is used in the normal manner when naming fused systems such as benz[a]anthracene
and benzo[b]thiophene. However, bicyclic hetero ring systems consisting of a benzene ring fused to
a monocyclic hetero ring named by the Hantzsch-Widman system (q.v.) receive a slightly different
treatment. Benzo- or benz- is placed directly in front of the Hantzsch-Widman name of the monocyclic hetero ring, and indicated hydrogen and locants describing the position of the heteroatoms are
cited, when necessary, in front of the resulting name.
4

5 4
3
1 2

5 4
1 2

4H-1,3-benzoxazine

1
4

1-benzoxepin

2-benzoxepin

b
a

2
3

naphthalene
fusion prefix = naphtho

furan
(base component)

O
naphtho[2,3-b]furan

1
i

h g

d c

f e

2
b

anthracene (base component)

1H-benzo[a]cyclopent[ j]anthracene

2
a b
c
d

t
n

o p

q r

m l

s
i h

pentaphene (base component)

9H-dibenzo[de,rst]pentaphene

Organic Chemist's Desk Reference, Second Edition
N

c
a

5 1N
4 3 2

quinoxaline
(base component)

imidazo

N
N

N1
2

pyrido

N
N

pyrido[1',2':1,2]imidazo[4,5-b]quinoxaline

Ring systems produced by fusion are completely renumbered, and the numbering bears no relation to the numbering of the fusion components. The rules for deciding correct numbering of a fused
system involve orienting the skeleton so as to put the maximum number of rings in a horizontal
row and the largest possible number of rings in the upper-right-hand quadrant. Numbering then
goes clockwise starting in the upper-right quadrant. In case of uncertainty, always consult the Ring
Systems Handbook.

of Individual
5 Nomenclature
Classes of Compound
5.1 Carbohydrates
Carbohydrate nomenclature impacts on stereochemistry, and on the nomenclature of compounds
other than mainstream carbohydrates (e.g., hydroxylactones), often named as modified carbohydrates in Chemical Abstracts Service (CAS) and elsewhere. For further stereochemical information
on carbohydrates, see Chapter 7.
For IUPAC guidelines on carbohydrate nomenclature see Pure Appl. Chem., 68, 1919–2008,
1996.

5.1.1 Fundamental Aldoses
The fundamental carbohydrates are polyhydroxyaldehydes (aldoses) and -ketones (ketoses). Of
these, the most important for nomenclature are the aldoses. An aldose, HOCH2(CHOH)n–2CHO,
has (n–2) chiral centres. The stereochemical designation of a fundamental aldose is arrived at by
assigning it to the d- or l-series depending on the absolute configuration of the highest-numbered
chiral centre (penultimate carbon atom) of the chain, together with the aldose name, which defines
the relative configuration of all the chiral centres, thus d-glucose. This system of stereodescription
is used extensively in organic chemistry to specify the absolute configurations of compounds that
can be related to carbohydrates. When applied in this general sense, the descriptors are italicised,
e.g., l-erythro-, d-gluco-.
The Dictionary of Carbohydrates, ed. P. M. Collins (see Section 1.2.1), is recommended for
an overview of all the fundamental types of carbohydrate. Each compound is classified under
one or more types of compound code, and perusal of the printed or electronic version can often
resolve uncertainties of nomenclature. The dictionary also forms part of the Combined Chemical
Dictionary.
Carbohydrates may be represented as Fischer, Haworth, or planar (Mills) diagrams, as well as
zigzag diagrams, as used for noncarbohydrates. Figure 5.1 shows how these representations are
related, and how to go from one to another.
In a Fischer projection of an open-chain carbohydrate, the chain is written vertically with carbon
number 1 at the top. The OH group on the highest-numbered chiral carbon atom is depicted on the
right in monosaccharides of the d-series and on the left in the l-series. To go from a Fischer projection to the correct absolute configuration, the groups attached to the horizontal bonds are pulled
above the plane of the paper. Rotation of a Fischer diagram by 180° in the plane of the paper is an
allowed operation that leaves the configuration unchanged.
Caution: Rotating a Fischer projection by 90° inverts the stereochemistry. Occasionally Fischer
diagrams are drawn horizontally to save space. This should never be done!

Organic Chemist's Desk Reference, Second Edition
1

CHO
OH

OH
HO

CHO
OH

OH
5

OH
HO
H C

CH2OH
D-glucose

Fischer
representation

CHO
1

CH2OH
O
5
1
OH
HO
OH
OH
Haworth

CH2OH

O
1

OH
Mills

α-D-glucopyranoside

CH2OH

Figure 5.1

The configuration of a group of consecutive asymmetric carbon atoms (such as >CHOH) containing one to four centres of chirality is designated by one of the configurational prefixes shown
in Table5.1.
Each prefix is preceded by d- or l-, depending on the configuration of the highest-numbered
chiral carbon atom in the Fischer projection of the prefix.
Table5.1
Configurational Prefixes
No. of Carbon Atoms
1
2
3
4

Prefixes
glyceroerythro-, threoarabino-, lyxo-, ribo-, xyloallo-, altro-, galacto-, gluco-,
gulo-, ido-, manno-, talo-

The names of the aldoses and their formulae are:
CHO

CHO
CHO
H C

CH2OH

CH2OH
D-glycerose

D-erythrose

D-threose

CHO

CH2OH
D-ribose

CH2OH
D-arabinose

CH2OH
D-xylose

CH2OH
D-lyxose

Nomenclature of Individual Classes of Compound
CHO

CHO

CH2OH

CH2OH
D-allose

CH2OH

CHO

D-gulose

CHO

CH2OH

D-mannose

D-glucose

D-altrose

CHO

CH2OH

D-galactose

D-idose

D-talose

Strictly, carbohydrates containing one chiral centre should have their configuration specified as
d- or l-glycero-. In practice this is often omitted, and such compounds can often be named equally
well as aliphatics.
1

CH2CH2CHO
OH
CH2OH

2,3-Dideoxy-D-glucopentose

CH2CH2C
5 O
CH2OH

CHO

OH
H

(S)-4,5-Dihydroxypentanal
(note different numbering)

H OH
HO

2,3-Dideoxy-D-glyceropentofuranose
= Tetrahydro-5-(hydroxymethyl)-2-furanol
or Tetrahydro-5-hydroxy-2-furanmethanol
(note different numbering)

The consecutive asymmetric carbon atoms need not be contiguous. Thus, the following four
arrangements are all l-erythro- (X is attached to the lowest-numbered carbon atoms).
X
X
X

C
C

CH2

CH2
HO

X
HO

CH2
H

C
Y

L-erythro-

Organic Chemist's Desk Reference, Second Edition

5.1.2 Fundamental Ketoses
The most important ketoses are the hexos-2-uloses HOCH2(CH2)n–3COCH2OH, such as fructose.
They have one less chiral centre than the aldoses of the same chain length; i.e., there are only four
diastereomerically different hexos-2-uloses.
Trivial names for the 2-hexuloses and their formulae are:
CH2OH

CH2OH
C

CH2OH

CH2OH
D-psicose

D-fructose

CH2OH
C

CH2OH

D-sorbose

D-tagatose

5.1.3 Modified Aldoses and Ketoses
Suffixes are employed to denote modification of functional groups in an aldose or ketose, e.g., by
oxidation of an OH group (Table5.2).

5.1.4 Higher Sugars
Sugars having more than six carbon atoms are named using two prefixes, one defining the configuration at C(2)–C(5) as in a hexose, and the other, which appears first in the name, defining the
configuration at the remaining chiral centres.
Examples of the use of configurational prefixes are:
1

CHO
H

CH2OH
HO

4
5

D-gluco

OH
D-glycero

CH2OH

CH2OH
D-arabino-3-hexulose

D-glycero-D-gluco-heptose

Table5.2
Suffixes Used in Carbohydrate Nomenclature
-ose
-odialdose
-onic acid
-uronic acid
-aric acid
-itol

Aldose
Dialdose
Aldonic acid
Uronic acid
Aldaric acid
Alditol

X = CHO, Y = CH2OH
X = Y = CHO
X = COOH, Y = CH2OH
X = CHO, Y = COOH
X = Y = COOH
X = Y = CH2OH

-ulose
-osulose
-ulosonic acid
-ulosuronic acid
-ulosaric acid
-odiulose

Ketose
Ketoaldose
Ulosonic acid
Ulosuronic acid
Ulosaric acid
Diketose

X = Y = CH2OH
X = CHO,Y = CH2OH
X = COOH, Y = CH2OH
X = CHO, Y = COOH
X = Y = COOH

X
(CHOH)x
Y

X
C

(CHOH)2
Y

(2-hexulose series)

Nomenclature of Individual Classes of Compound

5.1.5 Cyclic Forms: Anomers
When a monosaccharide exists in the heterocyclic intramolecular hemiacetal form, the size of the
ring is indicated by the suffixes -furanose, -pyranose, and -septanose for five-, six-, and sevenmembered rings, respectively.
Two configurations known as anomers may result from the formation of the ring. These are distinguished by the anomeric prefixes α- and β-, which relate the configuration of the anomeric carbon
atom to the configuration at a reference chiral carbon atom (normally the highest-numbered chiral
carbon atom). For example, consider the glucopyranoses:
CH2OH

CH2OH

O
1

OH
HO

OH
OH

α-D-

O
CH2OH
HO

OH
1

β-D-

OH
1

O
CH2OH
HO

HO
α-L-

β-L-

• In the d-series, the CH2OH is projected above the ring.
• In the l-series, the CH2OH is projected below the ring.
• In the α-series, the anomeric OH (at position 1) is on the opposite side of the ring from the
CH2OH group.
• In the β-series, the anomeric OH (at position 1) is on the same side of the ring as the
CH2OH group.
Suffixes used in carbohydrate nomenclature to indicate cyclic forms are as follows:
-ose (acyclic form), -ofuranose (five-membered ring), -opyranose (six-membered ring), -heptanose (seven-membered ring).
Similar suffixes can be constructed for dicarbonyl sugars and other modifications, for example:
-ulose
-ulopyranose
-osulose -opyranosulose or -osulopyranose
-odialdose -odialdopyranose.
The suffixes for the acids can be modified to indicate the corresponding amide, nitriles, acid
halides, etc., e.g., -uronamide, -ononitrile, and -ulosonyl chloride.

5.1.6 Glycosides
These are mixed acetals resulting from the replacement of the hydrogen atom on the anomeric (glycosidic) OH of the cyclic form of a sugar by a radical R derived from an alcohol or phenol (ROH).
They are named by changing the terminal -e of the name of the corresponding cyclic form of the
saccharide to -ide; the name of the R radical is put at the front of the name followed by a space.

Organic Chemist's Desk Reference, Second Edition
CH2OH
O OMe
OH
HO
OH
Methyl β- d-glucopyranoside

5.1.7 Disaccharides and Oligosaccharides
These are sugars produced where the alcohol forming the glycoside of a sugar is another sugar.
Where the resulting sugar has a (potentially) free aldehyde function, it is called a reducing disaccharide, and where both aldehyde functions are involved in the linkage (1 → 1) glycoside, it is a
non-reducing disaccharide.
CH2OH
O
OH

O
O

potential
aldehyde
function

CH2OH

maltose (4-O-α-D-glucopyranosyla reducing disaccharide

D-glucose),

CH2OH

HO
OH

OH
HOH2C
O

OH
α-D-galactopyranosyl α-D-galactopyranoside,
a non-reducing disaccharide

Abbreviations for use in representing oligosaccharides are shown in Table5.3. See Pure Appl.
Chem., 54, 1517, 1982.
Examples are:
Araf
Glcp
GalpA
d-GlcpN
3,6-AnGal

Arabinofuranose
Glucopyranose
Galactopyranuronic acid
2-Amino-2-deoxy-d-glucopyranose
3,6-Anhydrogalactose

5.1.8 Trivially Named Sugars
A number of names for modified sugars, which occur frequently in natural glycosides, are in common use.
Allomethylose
Cymarose
Diginose
Digitoxose

6-Deoxyallose
2,6-Dideoxy-3-O-methyl-ribo-hexose
2,6-Dideoxy-3-O-methyl-lyxo-hexose
2,6-Dideoxy-ribo-hexose

Nomenclature of Individual Classes of Compound

Fucose
Quinovose
Rhamnose
Olandrose
Thevetose

6-Deoxygalactose
6-Deoxyglucose
6-Deoxymannose
2,6-Dideoxy-3-O-methyl-arabino-hexose
6-Deoxy-3-O-methylglucose

Table5.3
Abbreviations for Use in
Representing Oligosaccharides
Hexoses

All
Alt
Gal
Glc
Gul
Ido
Man
Tal

allose
altrose
galactose
glucose
gulose
idose
mannose
talose

Pentoses

Ara
Lyx
Rib
Xyl

arabinose
lyxose
ribose
xylose

Other

Rha
Fuc
Fru

rhamnose
fucose
fructose

Suffixes

f
p
A
N

furanose
pyranose
uronic acid
2-deoxy-2-amino sugar

Prefixes

dlAn

configurational descriptor
configurational descriptor
anhydro

Note that if the absolute configuration of a sugar is not clear from the literature, CAS makes
certain assumptions, e.g., rhamnose is assumed to be l-.

5.2 Alditols and Cyclitols
5.2.1 Alditols
Reduction of the carbonyl group of an aldose (or of the oxo group in a ketose) gives the series of
alditols (called tetritols, pentitols, hexitols, etc., with 4, 5, 6, …, carbon atoms).
Because of their higher symmetry compared to the aldoses, the number of possible isomers is
lower, and some isomers are meso-forms or, in the C7 series, some isomers show pseudoasymmetry
(further described in Chapter 7).

Organic Chemist's Desk Reference, Second Edition
CH2OH
OH
OH
CH2OH

CH2OH
HO
OH
CH2OH

erythritol
(meso-)
CH2OH
OH
OH
OH
CH2OH

D-threitol

CH2OH

CH2OH
OH

ribitol
(meso-)
CH2OH
OH
OH
OH
OH
CH2OH
allitol
(meso-)

OH
OH
CH2OH

HO
OH
CH2OH

D-arabinitol

xylitol
(meso-)

D-lyxitol

CH2OH

CH2OH
OH

HO
OH
OH
OH
CH2OH
D-altritol

D-talitol

HO
OH
OH
CH2OH
D-glucitol

L-gulitol

CH2OH
HO
HO

CH2OH

CH2OH
OH

HO
OH
OH
OH
CH2OH

D-mannitol

HO
OH
CH2OH
D-iditol

HO
HO
OH
CH2OH
galactitol
(meso-)

Figure 5.2 The alditols derived from the C4, C5, and C6 monosaccharides in the d-series. Degenerate
symmetry means that there are only three pentitols and six hexitols.

Some isomers can therefore be named in more than one way. A choice is made according to a
special carbohydrate rule that says that allocation to the d-series takes precedence over alphabetical
assignment to the parent carbohydrate diastereoisomer.

5.2.2 Cyclitols
Posternak, L., The Cyclitols (San Francisco: Holden-Day, 1965).
For more information see: Hudlicky, T., and Cebulak, M., Cyclitols and Their Derivatives
(New York: VCH, 1993).
The most important cyclitols are the inositols (1,2,3,4,5,6-cyclohexanehexols). The relative arrangement of the six hydroxyl groups below or above the plane of the cyclohexane ring is denoted by an
italicised configurational prefix in the eight inositol stereoparents (the numerical locants indicate
OH groups that are on the same side of the ring):
cis-Inositol
epi-Inositol
allo-Inositol
myo-Inositol
muco-Inositol
neo-Inositol
chiro-Inositol
scyllo-Inositol

(1,2,3,4,5,6)
(1,2,3,4,5)
(1,2,3,4)
(1,2,3,5)
(1,2,4,5)
(1,2,3)
(1,2,4)
(1,3,5)

Six of these isomers (scyllo-, myo-, epi-, neo-, cis-, and muco-) have one or more planes of symmetry and are meso-compounds; chiro-inositol lacks a plane of symmetry and exists as the d- and

Nomenclature of Individual Classes of Compound

l-forms. In myo-inositol, the plane of symmetry is C-2/C-5; unsymmetrically substituted derivatives on C-1, C-3, C-4, and C-6 are chiral. Substitution at C-2 and/or C-5 gives a meso-product.
allo-Inositol appears to have a plane of symmetry, but at room temperature it is actually a racemate
formed of two enantiomeric conformers in rapid equilibrium.
5.2.2.1 Assignment of Locants for Inositols
(From the IUPAC-IUB 1973 Recommendations for the Nomenclature of Cyclitols; Biochem. J.,
153, 23–31, 1976; based upon proposals first issued in 1967; Biochem. J., 112, 17–28, 1969.)
• The lowest locants are assigned to the set (above or below the plane) that has the most OH
groups.
• For meso-inositols only, the C-1 locant is assigned to the (prochiral) carbon atom, which
has the l-configuration (see Chapter 7).
5.2.2.2 Absolute Configuration
Using a horizontal projection of the inositol ring, if the substituent on the lowest-numbered asymmetric carbon is above the plane of the ring and the numbering is counterclockwise, the configuration is assigned d, and if clockwise, the configuration is l (illustrated in Figure5.3 for myo-inositol
1-phosphate enantiomers).
Note that 1d-myo-inositol 1-phosphate is the same as 1l-myo-inositol 3-phosphate (and
1l-myo-inositol 1-phosphate is the same as 1d-myo-inositol 3-phosphate), but the lower locant has
precedence over the stereochemical prefix (d or l) in naming the derivative. A consequence of
applying the 1973 IUPAC-IUB rules to myo-inositol is that the numbering of C-2 and C-5 remains
invariant.
Before 1968, the nomenclature for inositols assigned the symbols d- and l- to the highest-numbered chiral centre, C-6. This convention was based on the rules for naming carbohydrates. For
substituted myo-inositols, in particular where C-1 and C-6 hydroxyl groups are trans, compounds
identified in the literature before 1968 as d- are now assigned 1l-.
Locants for unsubstituted inositols other than myo-inositol are shown in Figure5.3.
In order to clarify the metabolic pathways for substituted myo-inositols (in practice myo-inositol
phosphates), the lowest-locant rule, which gives priority to a 1l-locant has been relaxed, and numbering based on the 1d-series is now allowed (Biochem. J., 258, 1–2, 1989). This is to allow substances related by simple chemical or biochemical transformations to carry the same labels. Thus,
1l-myo-inositol 1-phosphate may now be called 1d-myo-inositol-3-phosphate.
In a further simplification, the symbol Ins may be used to denote myo-inositol, with the numbering of the 1d-configuration implied (unless the prefix l is explicitly added).

OPO3H2
3

1D-myo-inositol 1-(dihydrogen phosphate)

1L-myo-inositol 1-(dihydrogen phosphate)

4
5

H2O3PO
6

2
4

Figure 5.3

Organic Chemist's Desk Reference, Second Edition

1
5

cis-inositol
(1,2,3,4,5,6/0-)

5
4

scyllo-inositol
(1,3,5/2,4,6-)

1D-chiro-inositol*
(1,2,4/3,5,6-)
[formerly Dor (+)-inositol

muco-inositol
(1,2,4,5/3,6-)

epi-inositol
(1,2,3,4,5/6-)

2
4

5
6

neo-inositol
(1,2,3/4,5,6-)

allo-inositol
(1,2,3,4/5,6-)

5
4

1L-chiro-inositol*
(1,2,4/3,5,6-)
[formerly Lor (-)-inositol

Figure 5.4

5.3 Amino Acids and Peptides
See Pure Appl. Chem., 56, 595, 1984.

5.3.1 Amino Acids
In α-amino acids, the l-compounds are those in which the NH2 group is on the left-hand side of the
Fischer projection in which the COOH group appears at the top.
COOH
H2N C

COOH
H2N C

R
L-form

COOH

COOH
H C

NH2

R
D-form

Table5.4 lists the common α-amino acids. Most of these are found in proteins. Those marked *
are nonproteinaceous but common in peptides and are also used as stem names in CAS. The list is
in order of nomenclatural priority according to current CAS practice (2006), e.g., CAS name alanyl
arginine not argininylalanine. The order pre-2006 was different.
For all the amino acids in the table, except for cysteine, the l-form has the S-configuration. For
cysteine, the l-form has the R-configuration, because the –CH2SH group has higher priority than
–COOH according to the sequence rule (see Chapter 7).
Other one-letter abbreviations are as follows:
B Asparagine or aspartic acid
X Unspecified amino acid
Z Glutamine or glutamic acid
Other abbreviations that may be encountered in the literature include those listed in Table5.5.

Nomenclature of Individual Classes of Compound

Table5.4
α-Amino Acids Listed in Order of Precedence in CAS Nomenclature (2006 Revision)
Name

Abbreviations

Glutamic acid

Glu

Aspartic acid

Asp

Tryptophan

Trp

Histidine

His

Proline

Pro

R Group (Side Chain)
–CH2CH2COOH
–CH2COOH

Molecular Formula
C5H9NO4
C4H7NO4
C11H12N2O2

N
H
N

C6H9N3O2

C5H9NO2

N
O

Tyrosine

Tyr

Phenylalanine
Lysine
Norleucine*
Glutamine
Arginine
Ornithine*
Isoleucine

Phe
Lys
Nle
Gln (or Glu(NH2))
Arg
Orn
Ile

F
K

Alloisoleucine

aIle

Leucine
Norvaline*
Asparagines
Threonine
Allothreonine
Homoserine*
Methionine
Homocysteine
Valine
Isovaline
Serine
Cystine
Cysteine
Alanine

Leu
Nva (or Avl)
Asn
Thr
aThr
Hse
Met
Hcy
Val
Iva
Ser

β-Alanine*
Glycine

Q
R

OH
–CH2Ph
–CH2CH(CH3)2
–(CH2)3CH3
–CH2CH2CONH2

–(CH2)3NHC(NH2)NH
–(CH2)3NH2
–CH(CH3)CH2CH3
(R*,R*–)
–CH(CH3)CH2CH3
(R*,S*–)
–CH2CH(CH3)2
–CH2CH2CH3
–CH2CONH2
–CH(OH)CH3 (R*,S*–)
–CH(OH)CH3 (R*,R*–)
–CH2CH2OH
–CH2CH2SMe
–CH2CH2SH
–CH(CH3)2

–CH2CH3 + αCH3
–CH2OH

Cys
Ala

C (also stands for cytosine)
A (also stands for adenine)

–CH2SH
–CH3

βAla
Gly

G (also stands for guanine)

–CH2NH2 (replaces α-NH2)
–H

T (also stands for thymine)

Note: Nonprotein amino acids are marked *. Three-letter codes in brackets are not recommended.

C9H11NO3
C9H11NO2
C6H14N2O2
C6H13NO2
C5H10N2O3
C6H14N4O2
C5H12N2O2
C6H13NO2
C6H13NO2
C6H13NO2
C5H11NO2
C4H8N2O2
C4H9NO3
C4H9NO3
C4H9NO3
C5H11NO2S
C4H9NO2S
C5H11NO2
C5H11NO2
C3H7NO3
C6H12N2O4S2
C3H7NO2S
C3H7NO2
C3H7NO2
C2H5NO2

Organic Chemist's Desk Reference, Second Edition

Table5.5
Other Amino Acid–Related Abbreviations Found in the Literature
βAad
Aad
A2bu
Abu
εAhx
Ahx
2-MeAla
Ape
Apm
A2pr
Asp(NH2)
Asx
Dpm
Dpr
Gla
Glp or pGlu
or <Glu
Glx

3-Aminoadipic acid
2-Aminoadipic acid
2,4-Diaminobutanoic acid
2-Aminobutanoic acid
6-Aminohexanoic acid
2-Aminohexanoic acid (norleucine)
2-Methylalanine
2-Aminopentanoic acid (norvaline)
2-Aminopimelic acid
2,3-Diaminopropionic acid
Asparagine
Asparagine or aspartic acid
2,6-Diaminopimelic acid
2,3-Diaminopropionic acid
4-Carboxyglutamic acid
5-Oxoproline (pyroglutamic acid)
Glutamine or glutamic acid

Hsl
Hyl
5Hyl
Hyp
4Hyp
J (one-letter code)
MetO
MetO2
Mur
Neu
Neu5Ac
5-oxoPro
Sar
Sec or U
Ser(P)
Thx
Tyr(I2)
Tyr(SO3H)
Xaa

Homoserine lactone
5-Hydroxylysine
5-Hydroxylysine
4-Hydroxyproline
4-Hydroxyproline
Indistinguishable leucine or isoleucine
Methionine S-oxide
Methionine S,S-dioxide
Muramic acid
Neuraminic acid
N-Acetylneuraminic acid
5-Oxoproline (pyroglutamic acid)
Sarcosine
Selenocysteine (one-letter code U;
also stands for uridine)
Phosphoserine
Thyroxine
3,5-Diiodotyrosine
O4-Sulfotyrosine
Unspecified amino acid

5.3.2 Peptides
Peptides are oligomers notionally derived from amino acids by condensation to produce amide linkages. They are named either systematically or trivially.
The primary structure of a peptide is the amino acid sequence. The secondary structure is that
resulting from modifying bonds, especially hydrogen bonds and cysteine/cysteine dimerisation, and
the tertiary structure is the three-dimensional organisation resulting from the folding of a peptide
chain into helices, sheets, etc. The quaternary structure of a protein comprises the macrostructure
formed by the coming together of two or more smaller subunits.
Trivial names of peptides can be modified in the following ways to denote a change in the amino
acid sequence:
Replacement. When a peptide with a trivial name has an amino acid replaced by another
amino acid, the modified peptide can be named as a derivative of the parent peptide by
citing the new amino acid as a replacement. The new amino acid is designated by the
appropriate amino acid residue number:
H-Arg-Pro-Pro-Gly-Phe-Ser-Pro-Phe-Arg-OH = bradykinin
H-Arg-Pro-Pro-Gly-Phe-Ser-Phe-Phe-Arg-OH = 7-l-phenylalaninebradykinin
Extension. Extension of a trivially named peptide at the N-terminal end is denoted by substitutive nomenclature. Extension at the C-terminal end is made by citing the new amino acid
residues with locants derived by suffixing the highest locant with a, b, etc. Extension in the
middle of the chain is denoted by use of the term endo-:
H-Lys-Arg-Pro-Pro-Gly-Phe-Ser-Pro-Phe-Arg-OH = N2-l-lysylbradykinin
H-Arg-Pro-Pro-Gly-Phe-Ser-Pro-Phe-Arg-Arg-OH = 9a-l-argininebradykinin
H-Arg-Pro-Pro-Gly-Phe-Ser-Ala-Pro-Phe-Arg-OH = 6a-endo-l-alaninebradykinin

Nomenclature of Individual Classes of Compound

Removal. Removal of an amino acid residue is denoted using de-:
H-Pro-Pro-Gly-Phe-Ser-Pro-Phe-Arg-OH = 1-de-l-argininebradykinin
Various numbering methods have been used to indicate substitution or other modification in
or of the residues of a peptide. The method now recommended by IUPAC and introduced into the
Dictionary of Natural Products (see Section 1.2.1) uses numerical locants of the type 32, where 3 is
the locant of the substituent in the amino acid residue and 2 is the amino acid position in the ring or
chain, numbered from the N-terminal end, which is standard for all peptides). N5.4-methyloxytocin
would indicate a methyl substituent on N-5 of the glutamine residue at position 4 of oxytocin.
5.3.2.1 Recent CAS Peptide Nomenclature Revisions
For the 14th Collective Index period, several revisions in CAS peptide nomenclature have been
made, and further changes were made as part of the 2006 revisions.
• No structure is assigned a peptide name unless it contains at least two standard
amino acid residues. A standard amino acid residue is any amino acid that can stand
alone as a stereoparent (e.g., glycine or tryptophan), plus asparagine and glutamine.
2-Aminobutanoic acid and 2,4-diaminobutanoic acid are now considered nonstandard
amino acids.
• The 2006 changes to CAS nomenclature have reduced the number of peptide parent
names from about three thousand to fewer than one hundred of the most studied examples,
e.g., bradykinin. All others are now named systematically.
• The nomenclature of linear peptides has been simplified. The C-terminal residue is the
index heading parent, and the other residues are cited in the substituent, beginning with
the N-terminal residue and continuing from left to right in the sequence, e.g., l-lysine,
d-alanylglycyl-l-leucyl-. This replaces the many locants and enclosing marks that have
been used in the past, e.g., l-lysine, N2-[N-(N-d-alanylglycyl)-l-leucyl]-.
• S-oxides of sulfur-containing amino acids are now named at the peptide, e.g.:

MeS(O)CH2CH2CH(NH2)COOH
Butanoic acid, 2-amino-4-(methylsulfinyl), 9CI → methionine S-oxide

5.4 Natural Products (General)
The best information source on the names of natural products is the Dictionary of Natural Products
(DNP), which is part of the Chapman & Hall/CRC chemical database (see Section 1.2.1). DNP does
not give CAS names where these are lengthy, but it does have extensive coverage of CAS numbers,
from which the current CAS name can be readily obtained if needed.
Four different types of names can be applied to natural products:

1. Trivial names. Example: Corynoxine. These convey no structural information, and if the
structure has not been determined, this will be the only name available. Often derived
from the Latin binomial or other name for the originating species, e.g., strychnine from
Strychnos nux-vomica. They have the advantage that they are unchanged if there is a structure revision. There are, however, numerous duplications of trivial names in the literature.
IUPAC has promulgated proposals to systematise the endings of trivial names depending
on the functional groups present, but this is not widely used. The ending –in(e) is well
established for alkaloids, however.
2.Systematic names. Example: Methyl 6′-ethyl 1,2,2′3,6′,7′,8′,8′-octahydro-α-(methoxy
methylene)-2-oxospiro[3H-indole-3,1′(5′H-indolizine)]7′-acetate, (αE,1′S,6′S,7′S,8′aS)- is the

Organic Chemist's Desk Reference, Second Edition

current CAS name for corynoxine. There are many cases in which CAS numbering does
not correspond with the biogenetic schemes used by most natural products specialists.
Biogenetic schemes may be discontinuous where, for example, one or more carbon atoms
appear to have been lost during biosynthesis or new bonds formed.
3.Semisystematic names. Examples of semisystematic parents are corynoxan and labdane.
DNP makes widespread use of semisystematic names for terpenoids and steroids (where
skeletons such as labdane have not been used in CAS nomenclature since 8CI). IUPAC
gives tables of recognised semisystematic parent skeletons and directions for introducing
new ones, but in view of the discovery of ever more structurally complex types of natural
products, most authors have avoided this route. Semisystematic parents can be modified by
operators such as nor-, abeo.
CAS still uses this type of name for some types of natural product, but the 2006 CAS
nomenclature revisions have reduced the number in use by more than 3000.
4.Semitrivial names. These are names that are derived by appending a systematically
derived operator to a trivial parent. Examples are 8-(1,1-dimethylallyl)confusameline and
N-cyano-sec-pseudostrychnine. In general, such names should be avoided because of the
possibilities for confusion, especially when there is a structure revision or where there
is more than one numbering scheme in use for the parent skeleton. Trivial names should
be preferred.

5.5 Steroids
These are naturally occurring compounds and synthetic analogues based on the cyclopenta[a]phenanthrene skeleton. For further details, see Pure. Appl. Chem., 61, 1783, 1989.
Steroids are numbered, and rings are lettered as follows:
22

21
18
19

12
17
11
C 13 D 16
15
14
9 H

1
10 B
8
2
A
5 H 7
3
4
6

24
23

27
25
26

The following steroid names are the ones usually used as parent names:
androstane, bufanolide, campestane, cardanolide, cholane, cholestane, ergostane, estrane
(oestrane), furostan, gonane, gorgostane, poriferastane, pregnane, spirostan, and stigmastane. CAS has restricted the number of semisystematic skeletons in use.
Stereochemistry is denoted by α and β; ξ (xi) is used for positions of unknown stereochemistry.
For a steroid structure drawn in the normal manner, α- denotes that a substituent projects below
the plane of the paper and β- indicates that a substituent projects above the plane of the paper. At
a ring junction position, it is the H or Me group that determines whether the configuration is α- or
β-. The configuration of steroids at the ring junctions is assumed to be 8β,9α,10β,13β,14α unless
otherwise stated. The configuration at position 5 is not assumed and should be specified as 5α- or
5β-. The side chain at C(17) is normally 17β. In pregnane the stereochemistry at C(20) was formerly
designated 20α or 20β based on a Fischer projection, as follows:

Nomenclature of Individual Classes of Compound
CH3
βX

CH3
Yα

Terms used to describe modified steroid skeletons include nor (shortening of a side chain or contraction of a ring), homo (expansion of a ring), cyclo (formation of an additional ring), seco (fission
of a ring), and abeo (migration of a bond).

5.6 Lipids
For a detailed discussion see:
The Lipid Handbook with CD-ROM, 3rd ed., ed. F. D. Gunstone, J. L. Harwood, and A. J.
Dijkstra (Boca Raton, FL: CRC Press, 2007).
Lipids are fatty acids and their derivatives, and substances related biosynthetically or functionally to
them. Many fatty acids are still known by their trivial names (e.g., palmitic, linoleic).
The systematic names are often replaced by abbreviations of the form A:B(C). A indicates the
number of carbon atoms in the molecule, B represents the number of unsaturated centres, which are
usually cis-(Z-) alkenic, and C indicates the position and configuration of the unsaturation.
Palmitic = Hexadecanoic 16:0
Oleic = cis-9-Octadecenoic 18:1 (9Z)
Arachidonic = All-cis-5,8,11,14-eicosatetraenoic 20:4 (n – 3)
There are times when it is more appropriate to count from the methyl end and to use symbols
such as ω − 3 or n – 3 to indicate the position of the unsaturated centre closest to the methyl group. In
this case it is assumed that all unsaturation is methylene interrupted and has cis-(Z-) configuration.
sn- (stereospecifically numbered) is used to indicate the configuration of glycerol derivatives.
The carbon atom that appears at the top of that Fischer projection showing a vertical chain with the
OH group of C(2) to the left is designated as C(1).
1

CH2OH

CH2OPO3H2

sn-glycerol-3-phosphate

CH2OPO3H2
HO

CH2OH
sn-glycerol-1-phosphate

Iso acids are isomers branched at the (ω – 1) position, e.g., isopalmitic acid = (H3C)2CH
(CH2)12COOH.
Anteiso acids are branched at the (ω – 2) position, e.g., anteisopalmitic acid = H3CCH2CH(CH3)
(CH2)11COOH.

5.7 Carotenoids
Carotenoids are a class of hydrocarbons consisting of eight isoprenoid units.
The name of a specific carotenoid hydrocarbon is constructed by adding two Greek letters as
prefixes to the stem name carotene, these prefixes being characteristic of the two C9 end groups. The
prefixes are β- (beta), ε- (epsilon), κ- (kappa), φ- (phi), χ- (chi), and ψ- (psi).

Organic Chemist's Desk Reference, Second Edition
16

2
3

6
5

2
3

1
4

17
1

1
4

6
5
18

κ16

2
3

1
4

6
5
18

ψ18'

20
15

11
8

6
5

χ-

7
6
5

2
3

φ-

17
2
3

2
3

1
2 5
3 4

ε-

β-

17
6

6
5

14'

13'

12'

10'

11'

15'
20'

5'
6'

4'
1'

3'
2'

7'
19'

17' 16'

β,ε-carotene

For example, β,ε-carotene is as above.

5.8 Lignans
This is an extensive class of natural products typically formed by linkage of two (or more) C9 (cinnamyl) residues. Linkage occurs in a multitude of ways in addition to the β,β-bonding of the originally discovered lignan types. (Compounds with unusual linkages are often called neolignans.) They
can be named systematically, but this gives a large variety of different indexing parents. A more
attractive method is the Freudenberg/Weinges/Moss (now IUPAC-approved) scheme based on linkage of the two “lign” fragments. Application of this scheme is not completely straightforward. See
Pure Appl. Chem., 72, 1493–1523, 2000 and http://www.chem.qmul.ac.uk/iupac/lignan.

5.9 Nucleotides and Nucleosides
Nucleic acids, e.g., DNA, are ladder polymers of nucleotides, the heterocyclic bases of which (purines
and pyrimidines) encode the genetic information. The nucleosides are linked together through the
carbohydrate residues of the nucleotides to form the polymer. Nucleotides consist of nucleosides
O-phosphorylated in the sugar residues. The nucleosides, e.g., thymidine (below), consist of a heterocyclic base (in this case thymine) attached to a carbohydrate residue as an N-glycoside. The most
common bases found in nucleosides are shown in Table5.6, and the most common nucleosides in
Table5.7.
O
HN
HO

N
O

Thymidine

Nomenclature of Individual Classes of Compound

Table5.6
Common Nucleoside Bases
and Their Abbreviated Forms
Ade
Cyt
Gua
Hyp
Oro
Pur
Pyr
Shy
Sur
Thy
Ura
Xan

adenine
cytosine
guanine
hypoxanthine
orotate
unknown purine
unknown pyrimidine
thiohypoxanthine
thiouracil
thymine
uracil
xanthine

Table5.7
Abbreviations for Nucleosides
Ado
BrUrd
Cyd
Guo
Ino
Nuc
Oro
Puo
Pyd

A
B
C
D or hU
G
I
N
O
R
Y

adenosine
5-bromouridine
cytidine
5,6-dihydrouridine
guanosine
inosine
unspecified nucleoside
orotidine
unspecified purine nucleoside
unspecified pyrimidine nucleoside

Ψrd
Sno
Srd
Thd

ψ or Q
M or sI
S or sU
T

pseudouridine
thiouridine
6-thioinosine
ribosylthymine (not thymidine)

Urd
Xao

U
X

uridine
xanthosine

D
dThd
Nir
–P

2-deoxy
thymidine
ribosylnicotinamide
phosphoric residue

Organic Chemist's Desk Reference, Second Edition

5.10 Tetrapyrroles
This is a general term for porphyrins and bilane derivatives (cyclic and open-chain tetrapyrroles,
respectively), centered around a numerically limited number of natural products. Other IUPAC parent skeletons are phorbine, corrin, chlorin, and phthalocyanine (synthetic). See Pure Appl. Chem.,
59, 779–782, 1987, for the numbering of these skeletons.
The parent porphyrin system is called porphyrin (IUPAC) or porphine (CAS). In the old literature, the so-called Fischer numbering may be encountered.

18
17

16 N
24
15
14 23
13
12

4
5
22 6

21H,23H-porphine
or porphyrin

HN
β

N
10

NH
8

3
4

NH
11

N
γ

Fischer numbering

5.11 Organoboron Compounds
This is an extremely complex field, requiring major modifications to organic nomenclature and the
use of terms and techniques from inorganic nomenclature. “Even so, there are a significant number
of boron compounds whose names are not satisfactory to members of either the organic or inorganic
community” (see Fox and Powell, loc. cit., Chapter 27, for details). Because the number of hydrogen
atoms in neutral and anionic boron hydrides often bears no simple relationship to the number of
boron atoms, borane names must express the number of both.
Special prefixes closo-, nido- arachno-, catena-, hypho-, clado-, isocloso-, isonido-, isoarachno-,
canasto-, anello-, precloso-, hypercloso-, pileo-, and conjuncto- are found in the literature to describe
borane structures.
CAS uses the names boronic [BH(OH)2] and borinic [H2BOH] acid as parents. Inorganic chemists prefer the names dihydroxyborane and hydroxyborane, since they are not really acids. However,
the CAS system allows their derivatives to be named by analogy with other acids, such as the
phosphorus acids.

5.12 Organophosphorus (and Organoarsenic) Compounds
Organophosphorus chemistry is complicated by the stability of P(V) species in addition to trivalent
species such as phosphines, and the possibility of tautomerism between them. In addition, many
phosphorus compounds have been named as inorganics or biochemicals, as well as by the methods
of organic nomenclature, leading to a proliferation of names.
An extensive Dictionary of Organophosphorus Compounds (compiled by R. E. Edmundson)
was published in 1988, and has been updated as part of the CRC database (see Section 1.2.1). It
gives an extensive selection of alternative names. Substructure searching to locate compounds of
analogous structure can often resolve nomenclature difficulties for the commoner types.
Organoarsenic nomenclature is analogous.
Many phosphorus (and arsenic) compounds are named using functional replacement nomenclature in which replacement affixes are inserted into the names of the appropriate phosphorus
(arsenic) acids (Table5.8).

Nomenclature of Individual Classes of Compound

Table5.8
Parent Acid Names Used in Functional Replacement
Nomenclature of Phosphorus and Arsenic Compounds
(HO)3P
(HO)2HP
(HO)H2P
(HO)PO

(HO)3PO
(HO)2HPO
(HO)H2PO
(HO)PO2

Trivalent Acids
Phosphorous acid
(HO)3As
Phosphonous acid
(HO)2HAs
Phosphinous acid
(HO)H2As
Phosphenous acid
(HO)AsO

Arsenous acid
Arsonous acid
Arsinous acid
Arsenenous acid

Pentavalent Acids
Phosphoric acid
(HO)3AsO
Phosphonic acid
(HO)3HAsO
Phosphinic acid
(HO)H2AsO
Phosphenic acid
(HO)AsO2

Arsenic acid
Arsonic acid
Arsinic acid
Arsenenic acid

Table5.9
Functional Replacement Affixes for
Phosphorus and Arsenic Compounds
Affix

Replacement Operation

Amido
Azido
Bromide
Chloride
Cyanatido
Cyanide
(Dithioperoxo)
Fluoride
Hydrazido
Imido
Iodide
Isocyanitido
(Isothiocyanitido)
Nitride
Peroxo
Seleno
Telluro
Thio
(Thiocyanitido)

–OH by –NH2
–OH by –N3
–OH by –Br
–OH by –Cl
–OH by –OCN
–OH by –CN
–OH by –SSH
–OH by –F
–OH by –NHNH2
O by NH
–OH by –I
–OH by –NCO
–OH by –NCS

O and –OH by ≡N
–OH by –OOH

O by Se or –OH by –SeH
O by Te or –OH by –ThE
O by S or –OH by –SH
–OH by –SCN

Acidic functional replacement analogues of mononuclear phosphorus and arsenic acids are
named by citing the functional replacement affixes in alphabetical order just preceding the -ic acid
or -ous acid. The affixes used are listed in Table5.9.
The examples below are derived from phosphoric acid.
(H2N)(HO)2PO
Br(HO)2PO
Cl2(HO)PO
(HS)3PNH

Phosphoramidic acid
Phosphorobromidic acid
Phosphorodichloridic acid
Phosphorimidotrithioic acid

100

Organic Chemist's Desk Reference, Second Edition

Non-acidic functional replacement analogues are named by replacing the word acid with the
appropriate class name occurring earliest in the following list: hydrazide, halide, azide, amide, cyanide, nitride, imide. Other replacing groups are denoted by infixes, as described earlier for acidic
functional replacement analogues. The examples below are derived from phosphoric acid.
(H2N)3PO

Phosphoric triamide

Cl3PNH
(H2N)2(N3)PO

Phosphorimidic trichloride
Phosphorodiamidic azide

See also Fox and Powell, Chapter 25. On pages 243–245 there is a tabulation of substituting group
prefixes for phosphorus-containing groups, showing alternatives. For example, the group HP is
called phosphinidene in CAS, phosphinediyl by IUPAC (1979), and phosphanylidene by IUPAC
(1993).

5.13 Azo and Azoxy Compounds
Traditional nomenclature for azo compounds uses the multiplicative prefix azo –NN–, e.g., Ph–
NN–Ph = azobenzene, Ph–NN–C10H7 = 2-benzeneazonaphthalene or 2-phenylazonaphthalene.
This is difficult to apply for more complex unsymmetrical compounds, but remains in use. Another
form found in the older literature, especially for azo dyes, is naphthalene-2-azobenzene.
More recently, the parent name diazene –NN– (has also been called diimide; not recommended) was introduced, e.g., Ph–NN–Ph = diphenyldiazene. The 2006 CAS nomenclature
changes have included the following:
Azo, 9CI → diazenyl or 1,2-diazenediyl
Hydrazo, 9CI → 1,2-hydrazinediyl
In naming unsymmetrical azoxy compounds, the prefixes NNO- or ONN- are used to indicate the
position of the oxygen atom, e.g., Ph–N(O)N–C10H7 = phenyl-ONN-azoxynaphthalene. However,
post-2006, such azoxy compounds are named in CAS as (1-oxidodiazenyl) or (2-oxidodiazenyl).

5.14 Labelled Compounds
There are two main methods used for naming isotopically labelled compounds. For specifically
labelled compounds, IUPAC recommends forming the name by placing the nuclide symbols (plus
locants if necessary) in square brackets before the name of the unlabelled compounds or that part of
the name which is isotopically modified.
Chemical Abstracts uses the Boughton system, in which italicized nuclide symbols follow the
name or part of the name of the unlabelled compound as shown below. The symbols -d and -t are
used to denote deuterium and tritium, respectively.
CH2D2
H3C14CH2OH

CA
Methane-d2
Ethanol-1-14C

IUPAC
[2H2]Methane
[1-14C]Ethanol

The prefix deutero- (deuterio-) is used to denote replacement of H by D, and tritio- for replacement by T.

101

Nomenclature of Individual Classes of Compound

5.15 Tautomeric Compounds
The indexing and organisation of information relating to tautomeric or potentially tautomeric substances present severe difficulties to all information products. The issue is not how to name or
document each individual tautomer, but in what assumptions to make about which structures are
tautomeric, and how to organise information that may be imprecisely given in the literature under
various structures, often without clear experimental data.
CAS has fairly precise rules for denoting which structural systems are deemed to be tautomeric,
and to which tautomer indexing is directed. In CAS nomenclature 1972–2006, tautomeric substances were often indexed under theoretical tautomers, e.g., the 1H- form of purines, which had no
practical existence. CAS numbers for tautomeric substances therefore often referred to unknown
tautomers.
This nomenclature-based CAS policy has now been replaced by a structure-based policy for
selecting the preferred tautomer, giving a closer relationship with physical reality.
H
N

N
H
6(5H)-Pteridinone, 1,7-dihydro, 9CI → 6(5H)-pteridinone, 7,8-dihydro

and Miscellaneous
6 Acronyms
Terms Used in Describing
Organic Molecules
6.1 A
bbreviations and Acronyms for Reagents and Protecting
Groups in Organic Chemistry
This list is based, in part, on the compilation of abbreviations and acronyms by Daub, G. H., et al.,
Aldrichimica Acta, 17(1), 13–23, 1984 (reproduced with permission), augmented by some acronyms used
in Science of Synthesis: Houben-Weyl Methods of Molecular Transformations, Vols. 1–48 (Stuttgart:
Thieme, 2000–2009) and in Kocieński, P. J., Protecting Groups, 3rd ed. (Stuttgart: Thieme, 2004), respectively, which are reproduced by permission of the publisher. More acronyms, particularly those currently
in use for protecting groups, may be found in P. G. M. Wuts and T. W. Greene, Greene’s Protective
Groups in Organic Synthesis, 4th ed. (New York: Wiley, 2006). At the time of publication of this book,
there is a useful website hosted by the Freie Universität Berlin, which lists abbreviations and acronyms,
with an emphasis on those from the organic chemistry literature: http://www.chemie.fu-berlin.de/cgi-bin/
acronym. The German company FIZ CHEMIE Berlin also identifies acronyms used in organic chemistry together with their chemical structures at http://www.fiz-chemie.de/akronyme/Â�akronyme.pl.
In the list printed below, the same abbreviation is sometimes used for different reagents or protecting groups, and a few acronyms are based on obsolete or misleading nomenclature (e.g., DMPU
for N,N′-dimethylpropyleneurea, which is usually named 1,3 dimethyl-3,4,5,6-tetrahydro-2(1H)pyridmidinone). The use of o- (ortho), m- (meta), and p- (para) is retained in the name of the reagent
or protecting group to emphasise the derivation of the abbreviation or acronym. Abbreviations for
amino acids, nucleotides, nucleosides, and carbohydrates are omitted in this section but may be
found in Chapter 5.
AA
AAA
AAAF
AAMX
AAO
AAOA
AAOC
AAOT
ABA
ABL
ABO
ABTS
Ac
7-ACA
acac
ACAC (or acac)

Anisylacetone
Acetoacetanilide
2-(N-Acetoxyacetylamino)fluorene
Acetoacet-m-xylidide (m-acetoacetoxylidide)
Acetaldehyde oxime
Acetoacet-o-anisidide (o-acetoacetanisidide)
Acetoacet-o-chloroanilide (o-acetochloranilide)
Acetoacet-o-toluidide (o-acetoacetotoluidide)
Abscisic acid
α-Acetyl-γ-butyrolactone
2,7,8-Trioxabicyclo[3.2.1]octyl
2,2′-Azinobis(3-ethylbenzothiazoline-6-sulfonic acid)
Acetyl
7-Aminocephalosporanic acid
Acetylacetonato
Acetylacetonate

103

104
ACES
Acm
AcOH
AcOZ
Ad
ADA
7-ADCA
ADDC
ADMA
Adoc
Adpoc
AEP (or AEPZ)
AET
AIBN
AICA
AIP
All
Alloc (or aloc)
Alocam
Am
AMBA
AMEO
AM-ex-OL
AMMO
bis-AMP
AMPD
AMPS
AMTCS
ANM
ANPP
ANS-NH4
AOC
AOM
6-APA
APAP
APDC
APDTC
APG
APTP
Ar
ASC
ATA
ATC
ATEE
1,3-BAC
BAL
BAO
BaP (BAP)
BBA
9-BBN

Organic Chemist's Desk Reference, Second Edition
N-(2-Acetamido)-2-aminoethanesulfonic acid
Acetamidomethyl
Acetic acid
p-Acetoxybenzyloxycarbonyl
Adamantyl
N-(2-Acetamido)iminodiacetic acid [N-(carbamoylmethyl)iminodiacetic acid]
7-Aminodesacetoxycephalosporanic acid
Ammonium diethyldithiocarbamate
Alkyldimethylamine
1-Adamantyloxycarbonyl
1-(1-Adamantyl)-1-methylethoxycarbonyl
1-(2-Aminoethyl)piperazine
S-2-Aminoethylisothiouronium bromide hydrobromide
2,2′-Azobis(isobutyronitrile)
5(4)-Aminoimidazole-4(5)-carboxamide
Aluminium isopropoxide
Allyl
Allyloxycarbonyl
Allyloxycarboxylaminomethyl
Amyl
3-Amino-4-methoxybenzanilide
3-Aminopropyltriethoxysilane
4-Chloro-2-phenylquinazoline
2-Aminopropyltrimethoxysilane
N-Bis(hydroxyethyl)-2-amino-2-methyl-1-propanol
2-Amino-2-methyl-1,3-propanediol
2-Acrylamido-2-methylpropanesulfonic acid
Amyltrichlorosilane
N-(4-Anilino-1-naphthyl)maleimide
4-Azido-2-nitrophenyl phosphate
8-Anilinonaphthalene-1-sulfonic acid, ammonium salt
Allyloxycarbonyl
p-Anisyloxymethyl [(4-methoxyphenoxy)methyl]
6-Aminopenicillanic acid
N-Acetyl-p-aminophenol
Ammonium 1-pyrrolidinecarbodithioate
Ammonium 1-pyrrolidinedithiocarbamate
p-Azidophenylglyoxal hydrate
N-(4-Azidophenylthio)phthalimide
Aryl
p-Acetylaminobenzenesulfonyl chloride
Anthranilamide
Ethyltrichlorosilane
N-Acetyl-l-tyrosine ethyl ester monohydrate
1,3-Bis(aminomethylmethyl)cyclohexane)
2,3-Dimercapto-1-propanol (British anti-Lewisite)
Bis(4-aminophenyl)-1,3,4-oxadiazole
Benzo[a]pyrene
Barbituric acid
9-Borabicyclo[3.3.1]nonane

Acronyms and Miscellaneous Terms Used in Describing Organic Molecules
9-BBN-H
BBO
BBOD
BBOT
BBP
BCA
BCNU
BCP
BCPC
bda
BDA
BDMA
BDPA
BDT
Benzostabase
BES
BGE
BHA
BHC
BHMF
BHMT
BHT
BIC
BICINE
BINAL-H
BINAP
bipy
bis-DHP
BLO
Bmpc
Bmpm
BMS
Bn
BN
BNAH
BNB
Bnz
BOC (or Boc or t-BOC)
BOC-ON
BOC-OSU
BOC-OTCP
BOM
BOMBr
BOMCl
BON
BOP
BOPCl
BPBG
BPC
BPCC

9-Borabicyclo[3.3.1]nonane
2,5-Bis(4-biphenylyl)oxazole
2,5-Bis(4-biphenylyl)-1,3,4-oxadiazole
2,5-Bis(5-tert-butyl-2-benzoxazolyl)thiophene
Benzyl butyl phthalate
N-Benzylcyclopropylamine
1,3-Bis(2-chloroethyl)-1-nitrosourea
Butyl carbitol piperonylate
sec-Butyl N-(3-chlorophenyl)carbamate
Benzylidene acetone
Butane-2,3-diacetal
Benzyldimethylamine
α,γ-Bisdiphenylene-β-phenylallyl, free radical
1,3-Benzodithiolan-2-yl
1,1,3,3-Tetramethyl-1,3-disilaisoindoline
N,N-Bis(2-hydroxyethyl)-2-aminoethanesulfonic acid
Butyl glycidyl ether
3-tert-Butyl-4-hydroxyanisole
Benzene hexachloride
2,5-Bis(hydroxymethyl)furan
Bis(hexamethylene)triamine
2,6-Di-tert-butyl-4-methylphenol (butylated hydroxytoluene)
5-Benzisoxazolylmethoxycarbonyl
N,N-Bis(2-hydroxyethyl)glycine
2,2′-Dihydroxy-1,1′-binaphthyllithium aluminium hydride
2,2′-Bis(diphenylphosphino)-1,1′binaphthyl
2,2′-Bipyridyl
6,6′-Bis(3,4-dihydo-2H-pyran)
γ-Butyrolactone
2,4-Dimethylthiophenoxycarbonyl
1,1-Bis(4-methoxyphenyl)-1-pyrenylmethyl
Borane-methyl sulfide complex
Benzyl (also Bzl or Bnz)
Benzonitrile
1-Benzyl-1,4-dihydronicotinamide
2,4,6-Tri-tert-butylnitrosobenzene
(See Bn)
tert-Butoxycarbonyl
2-(tert-Butoxycarbonyloxyimino)-2-phenylacetonitrile
N-(tert-Butoxycarbonyloxy)succinimide
tert-Butyl 2,4,5-trichlorophenyl carbonate
Benzyloxymethyl
Benzyl bromomethyl ether
benzyl chloromethyl ether
β-Hydroxynaphthoic acid
Benzotriazol-1-yloxytris(dimethylamino)phosphonium hexafluorophosphate
Bis(2-oxo-3-oxazolidinyl)phosphinic chloride
Butyl phthalyl butyl glycolate
Butylpyridinium chloride
2,2′-Bipyridinium chlorochromate

105

106
BPO
Bpoc
BPPM
Bromo-PADAP
Bs
BSA
BSC
BSH
BSOCOES
BST chloride
BSTFA
Bt
BTA
BTAF
BTDA
BTEAC
BTFA
BTMSA
Bts
Bu
t-Bumeoc
iBu
sBu
tBu
BuOH
t-BuOK
Bus
Bz
Bzh
Bzl
CAM
CAN
CAP
CAP-Li2
CAPS
CAT
CBC
Cbm
CBn (or Cb or Cbo)
Cbz (or CBZ or Z)
CBZ-HONB
Cbz-OSu
CCH
CCNU
CD
CDA
CDAA
CDC
CDEC
CDTA

Organic Chemist's Desk Reference, Second Edition
2-(4-Biphenylyl)-5-phenyloxazole
1-Methyl-1-(4-biphenylyl)ethoxycarbonyl
(2S,4S)-N-tert-Butoxycarbonyl-4-diphenylphosphino-2-diphenylphosphinomethylpyrrolidine
2-(5-Bromo-2-pyridylazo)-5-diethylaminophenol
4-Bromobenzenesulfonyl (brosyl)
N,O-Bis(trimethylsilyl)acetamide
N,O-Bis(trimethylsilyl)carbamate
Benzenesulfonyl hydrazide
Bis[2-(succinimidooxycarbonyloxy)ethyl] sulfone
2-(2-Benzothiazolyl)-5-styryl-3-(4-phthalhydrazidyl)tetrazolium chloride
N,O-Bis(trimethylsilyl)trifluoroacetamide
Benzotriazol-1-yl (1-benzotriazolyl)
Benzotrifluoroacetone
Benzyltrimethylammonium fluoride
3,3′,4,4′-Benzophenonetetracarboxylic dianhydride
Benzyltriethylammonium chloride
Bis(trifluoroacetamide)
Bis(trimethylsilyl)acetylene
Benzothiazole-2-sulfonyl
Butyl
1-(3,5-Di-tert-butylphenyl)-1-methylethoxycarbonyl
iso-Butyl
sec-Butyl
tert-Butyl
Butanol
Potassium tert-butoxide
tert-Butylsulfonyl
Benzoyl
Diphenylmethyl (benzhydryl)
Benzyl (also Bn)
Carboxamidomethyl
Cerium(IV) ammonium nitrate
Cellulose acetate phthalate
Carbamoyl phosphate, dilithium salt
3-Cyclohexylamino-1-propanesulfonic acid
2-Chloro-4,6-bis(ethylamino)-s-triazine
Carbomethoxybenzenesulfonyl chloride
Carbamoyl
Benzyloxycarbonyl (or carbobenzoxy)
Benzyloxycarbonyl
N-Benzyloxycarbonyloxy-5-norbornene 2,3-dicarboximide
N-[(Benzyloxycarbonyl)oxy]succinimide
Cyclohexylidenecyclohexane
1-(2-Chloroethyl)-3-cyclohexyl-1-nitrosourea
Cyclodextrin
Cyclohexane-1,2-diacetal
Chlorodiallylacetamide
Cycloheptaarylose-dansyl chloride complex
2-Chloroallyl N,N-diethyldithiocarbamate
trans-1,2-Diaminocyclohexane-N,N,N′,N′-tetraacetic acid

Acronyms and Miscellaneous Terms Used in Describing Organic Molecules
CE
Cee
CEEA
CEEMT
CEMA
CEPEA
CHAPS
CHES
Chiraphos
CHP
CHT
5-CIA
CMA
CMC
CMC
CMDMCS
CMPI
CNAP
CNT
Coc
cod (or COD)
cot (or COT)
Cp (or cp)

Cyanoethyl
1-(2-Chloroethoxy)ethyl
N-(2-Cyanoethyl)-N-ethylamine
N-(2-Cyanoethyl)-N-ethyl-m-toluidine
N-(2-Cyanoethyl)-N-methylaniline
N-(2-Hydroxyethyl)-N-(2-cyanoethyl)aniline
3-[(3-Cholamidopropyl)dimethylammonio]propanesulfonate
2-(Cyclohexylamino)ethanesulfonic acid
2,3-Bis(diphenylphosphino)butane
N-Cyclohexyl-2-pyrrolidone
Cycloheptatriene
5-Chloroisatoic anhydride
Carbomethoxymaleic anhydride
Carboxymethyl cellulose
1-Cyclohexyl-3-(2-morpholinoethyl)carbodiimide
(Chloromethyl)dimethylchlorosilane
2-Chloro-1-methylpyridinium chloride
2-Naphthylmethyl carbamate
Cyanotoluene
Cinnamyloxycarbonyl
1,5-Cyclooctadiene
Cyclooctatetraene

Cp* (or cp*)
4-CPA
m-CPBA
CPTEO
CPTMO
CPTr
CSA
CSI
CTA
CTAB (or CTABr)
CTACl
CTACN
CTAOH
CTFB
CTMP
Cy
CYAP
cyclam
CYP
2,4-D
D
DAA
DAA
DAB
DAB
DABCO (or TED)
DABITC

η5-Pentamethylcyclopentadienyl
4-Chlorophenoxyacetic acid
m-Chloroperbenzoic acid
3-Chloropropyltriethoxysilane
3-Chloropropyltrimethoxysilane

η5-Cyclopentadienyl

4,4′,4″-Tris(4,5-dichlorophthalimido)triphenylmethyl
10-Camphorsulfonic acid
Chlorosulfonyl isocyanate
Citraconic anhydride
Cetyltrimethylammonium bromide
Cetyltrimethylammonium chloride
Cetyltrimethylammonium cyanide
Cetyltrimethylammonium hydroxide
4-Trifluoromethylbenzyl carbamate
1-[(2-Chloro-4-methylphenyl)-4-methoxy-4-piperidinyl]
Cyclohexyl
O,O-Dimethyl O-(p-cyanophenyl) phosphorothioate
1,4,8,11-Tetraazacyclotetradecane
p-Cyanophenyl ethyl phenylphosphonothioate
2,4-Dichlorophenoxyacetic acid
2,2′-Dithiodibenzoic acid
Diacetone acrylamide
Diacetone alcohol
p-Dimethylaminoazobenzene
Diaminobenzidine (usually 3,3′)
1,4-Diazabicyclo[2.2.2]octane
4-(N,N-Dimethylamino)azobenzene-4′-isothiocyanate

107

108

Organic Chemist's Desk Reference, Second Edition

DABS-Cl
3,5-DACB
DACH
DACM-3
DAD
DAM
DAMN
DANSYL
DAP
DAP
DAPI
DAS
DAST
DAST
DATMP
2,4-DB
dba
DBA
DBAD
DBC∙Br2
DBCP
DBDPO
DBD-Tmoc
DBIC
DBMIB
DBN
DBN
DBP
DBPC
DBPO
DBS
DBS
DBU
2,4-DCAD
DCAF
DCB
2,4-DCBA
2,4-DCBC

4-(N,N-Dimethylamino)azobenzene-4′-sulfonyl chloride
3,5-Diaminochlorobenzene
trans-1,2-Diaminocyclohexane
N-(7-Dimethylamino-4-methyl-3-coumarinyl)maleimide
(See DEAD)
Di(4-methoxyphenyl)methyl
Diaminomaleonitrile
5-Dimethylaminonaphthalene-1-sulfonyl
Diallyl phthalate
Diammonium phosphate

2,4′-DCBP
2,4-DCBTF
3,4-DCBTF
DCC
DCCI
DCE
DCEE
DCHA
DCHBH
DCI-HCl
DCM
DCME

2,4′-Dichlorobenzophenone
2,4-Dichlorobenzotrifluoride
3,4-Dichlorobenzotrifluoride
Dicyclohexylcarbodiimide
(See DCC)
Dichloroethane
Dichloroethyl ether
Dicyclohexylamine
Dicyclohexylborane

4′,6-Diamidino-2-phenylindole dihydrochloride
4,4′-Diaminostilbene-2,2′-disulfonic acid
N,N-Diethylaminosulfur trifluoride
N,N-Dimethylaminosulfur trifluoride
Diethylaluminium 2,2,6,6-tetramethylpiperidide
2,4-Dichlorophenoxybutyric acid
Dibenzylideneacetone
Dibenz[a,h]anthracene
Di-tert-butyl azodicarboxylate
Dibenzo-18-crown-6/Br2
1,2-Dibromo-3-chloropropane
Decabromodiphenyl ether
2,7-Di-tert-butyl [9-(10,10-dioxo-10,10,10,10-tetrahydroxanthyl)]methoxycarbonyl
Dibutylindolocarbazole
Dibromomethylisopropylbenzoquinone
1,5-Diazabicyclo[4.3.0]non-5-ene
p,p′-Dinitrobenzhydryl
Dibutyl phthalate
2,6-Di-tert-butyl-p-cresol
Dibenzoyl peroxide
Dibenzosuberyl
Dibutyl sebacate
1,8-Diazabicyclo[5.4.0]undec-7-ene
2,4-Dichlorobenzaldehyde
2′,4′-Bis[di(carboxymethyl)aminomethyl]fluorescein
Dicyanobenzene
2,4-Dichlorobenzoic acid
2,4-Dichlorobenzyl chloride

1-(3′,4′-Dichlorophenyl)-2-isopropylaminoethanol hydrochloride
Dichloromethane
Dichloromethyl methyl ether

Acronyms and Miscellaneous Terms Used in Describing Organic Molecules
DCOC
DCPD
DCPhth
2,4-DCT
3,4-DCT
2,4-DCTC
3,4-DCTC
DCU
DDA
DDB
DDD
o,p′-DDD
p,p′-DDD
o,p′-DDE
p,p′-DDE
DDH
Ddm
DDM
DDM
DDMU
DDOH
DDP
DDQ
DDS
DDS
DDSA
o,p′-DDT
p,p′-DDT
DDVP
DDZ
DEA
DEAA
DEAC
DEAD (or DEADCAT)
DEAE-cellulose
DEAH
DEAI
DEAP
DEASA
DEC
DEDM
DEII
DEIPS
DEP
DEP
DEPC
DEPHA
DESS
DET
DFP

2,4-Dichlorobenzoyl chloride
Dicyclopentadiene
4,5-Dichlorophthaloyl
2,4-Dichlorotoluene
3,4-Dichlorotoluene
2,4-Dichlorobenzotrichloride
3,4-Dichlorobenzotrichloride
N,N-Dichlorourethane
4,4′-Dichlorodiphenylacetic acid
2,3-Dimethoxy-1,4-bis(dimethylamino)butane
2,2′-Dihydroxy-6,6′-dinaphthyl disulfide
1-(o-Chlorophenyl)-1-(p-chlorophenyl)-2,2-dichloroethane
2,2-Bis(p-chlorophenyl)-1,1-dichloroethane
1-(o-Chlorophenyl)-1-(p-chlorophenyl)-2,2-dichloroethylene
2,2-Bis(p-chlorophenyl)-1,1-dichloroethylene
1,3-Dibromo-5,5-dimethylhydantoin
4,4′-Dimethoxydiphenylmethyl [bis-(4-methoxyphenyl)methyl]
4,4′-Dichlorodiphenylmethane
Diphenyldiazomethane
4,4′-Dichlorodiphenyl-2-chloroethylene [1-Chloro-2,2-bis(4′-chlorophenylethene)]
4,4′-Dichlorodiphenylethanol
Dichlorodiammineplatinum
2,3-Dichloro-5,6-dicyano-1,4-benzoquinone
p,p′-Diaminodiphenyl sulfone
Dihydroxydiphenyl sulfone
Dodecenylsuccinic anhydride
1-(o-Chlorophenyl)-1-(p-chlorophenyl)-2,2,2-trichloroethane
1,1-bis(p-Chlorophenyl)-2,2,2-trichloroethane
Dimethyl 2,2-dichlorovinyl phosphate
α,α-Dimethyl-3,5-dimethoxybenzyloxycarbonyl
N,N-Diethylaniline
N,N-Diethylacetoacetamide
Diethylaluminium chloride
Diethyl azodicarboxylate
Diethylaminoethyl cellulose
Diethylaluminium hydride
Diethylaluminium iodide
2,2-Diethoxyacetophenone
N,N-Diethylaniline-3-sulfonic acid
2-Diethylaminoethyl chloride hydrochloride
Diethyl diazomalonate
Diethylindoloindole
Diethylisopropylsilyl
Diethyl phthalate
Diethyl pyrocarbonate
Diethylphosphoryl cyanide
Di(2-ethylhexyl)phosphoric acid
Diethyl succinylsuccinate
Diethyl tartrate
Diisopropyl fluorophosphate

109

110
DHA
DHA
DHBA
DHBP
DHEBA
DHET
DHN
DHP
DHP
DIAD
DIB
DIBAC
DIBAH
DIBAL
DIBAL-H
DIC
DIC
DIDP
DIEA
DI-ET
Diglyme
DiHPhe
Dim
Dimethyl-POPOP
Dimsyl Na
Diop (or DIOP)
Diox
DIPC
DIPEA
DIPHOS (or diphos)
DIPSO
DIPT (or DiPT)
Di-SNADNS
DITC
2,6-DMA
DMA or DMAc
DMA
DMAA
DMAC
DMAD
DMA-DEA
DMAEMA
DMAP
DMAP
DMAPMA
DMB
DMB
DMC
dmch
DMCS

Organic Chemist's Desk Reference, Second Edition
Dehydroacetic acid
9,10-Dihydroanthracene
3,4-Dihydroxybenzylamine hydrobromide
Dihydroxybenzophenone (usually 4,4′)
1,2-Dihydroxyethylenebisacrylamide
Dihydroergotoxine
5,12-Dihydronaphthacene
Diheptyl phthalate
Dihydropyran
Diisopropyl diazodicarboxylate
1,3-Diphenylisobenzofuran
Diisobutylaluminium chloride
Diisobutylaluminium hydride
(See DIBAH)
(See DIBAH)
Diisopropylcarbodiimide
(Dimethylamino)isopropyl chloride hydrochloride
Diisodecyl phthalate
Diisopropylethylamine
N,N-Diethyl-p-phenylenediamine monohydrochloride
Diethylene glycol dimethyl ether
2,5-Dihydroxyphenylalanine
2-(1,3-Dithianyl)methyl
1,4-Bis(4-methyl-5-phenyloxazol-2-yl)benzene
Sodium methylsulfinylmethide
2,3-O-Isopropylidene-2,3-dihydroxy-1,4-bis(diphenylphosphino)butane
Dioxane
2-Dimethylaminoisopropyl chloride hydrochloride
Diisopropylethylamine
Ethylenebis(diphenylphosphine); see also dppe
3-[Bis(2-hydroxyethyl)amino]-2-hydroxy-1-propanesulfonic acid
Diisopropyl tartrate
2,7-Bis(4-sulfo-1-naphthylazo)-1,8-dihydroxynaphthalene-3,6-disulfonic acid
1,4-Phenylene diisocyanate
2,6-Dimethylanisole
N,N-Dimethylacetamide
N,N-Dimethylaniline
N,N-Dimethylacetoacetamide
(See DMA, dimethylacetamide)
dimethyl acetylenedicarboxylate
N,N-Dimethylacetamide diethyl acetal
2-Dimethylaminoethyl methacrylate
Dimethylaminopropylamine
4-(Dimethylamino)pyridine
Dimethylaminopropyl methacrylamide
4,4′Dichloro-α-methylbenzhydrol
2,4- or 3,4-Dimethoxybenzyl
2-(Dimethylamino)ethyl chloride
6,6-Dimethylcyclohexadienyl
Dimethylchlorosilane

Acronyms and Miscellaneous Terms Used in Describing Organic Molecules
DMDAAC
DMDO
DME
DMECS
DMEU
DMF
DMF-DMA
DMI
DMIPS
DMM
Dmoc
Dmp
2,6-DMP
DMP
DMP
DMP
DMP-30
DMPA
DMPC
dmpd
DMPE
DMPM
DMPO
DMPP
DMPS
DMPU
DMS
DMS
DMSO
DMSS
DMT
DMT
DMTD
DMTr
DMTSF
DMTST
DNA
DNAP
DNB
DNBS
DNBSC
DNF
DNFA
DNFB
DNMBS
DNP
DNP
DNP
DNPBA
2,6-DNPC

111

Dimethyldiallylammonium chloride
Dimethyldioxirane
1,2-Dimethoxyethane (glyme)
Dimethylethylchlorosilane
N,N′-Dimethylethyleneurea
N,N-Dimethylformamide
Dimethylformamide dimethyl acetal
1,3-Dimethyl-2-imidazolidinone
Dimethylisopropylsilyl
Dimethylmaleoyl
Dithianylmethoxycarbonyl
Dimethylphosphinyl
2,6-Dimethylphenol
Dimethyl phthalate
Dimethyl pyrocarbonate
2,2-Dimethoxypropane
2,4,6-Tris(dimethylaminomethyl)phenol
2,2-Dimethoxy-2-phenylacetophenone
3-Dimethylaminopropyl chloride hydrochloride
2,4-Dimethylpentadienyl
1,2-Bis(dimethylphosphino)ethane
2,4- or 3,4-Dimethoxybenzyl
5,5-Dimethyl-1-pyrroline N-oxide
1,1-Dimethyl-4-phenylpiperazinium iodide
2,3-Dimercapto-1-propanesulfonic acid (sodium salt)
1,3-Dimethyl-3,4,5,6-tetrahydropyrimidin-2(1H)-one (also named N,N′-dimethylpropyleneurea)
4,6-Dimethoxybenzene-1,3-disulfonyl chloride
Dimethyl sulfide
Dimethyl sulfoxide
Dimethyl succinylsuccinate
Dimethyl tartrate
Dimethyl terephthalate
2,5-Dimercapto-1,3,4-thiadiazole
Di(4-methoxyphenyl)phenylmethyl or dimethoxytrityl
Dimethyl(methylthio)sulfonium fluoroborate
Dimethyl(methylthio)sulfonium Trifluoromethanesulfonate
Deoxyribonucleic acid
4-(2,4-Dinitrophenylazo)-9-phenanthrol
p,p′-Dinitrobenzhydryl
2,4-Dinitrobenzenesulfonic acid
2,4-Dinitrobenzenesulfenyl chloride
2,4-Dinitrofluorobenzene
2,4-Dinitro-5-fluoroaniline (Bergmann’s reagent)
(See DNF)
4-(4,8-Dimethoxynaphthylmethyl)benzenesulfonyl
2,4-Dinitrophenyl
2,4-Dinitrophenylhydrazine
Dinonyl phthalate
3,5-Dinitroperoxybenzoic acid or 2,4-dinitroperoxybenzoic acid
2,6-Dinitro-p-cresol

112
Dnp-F
DNPF
DNS
DNS
DNSA
DNS-BBA
DNTC
DOA
Dobz
DOP
DOPET
2,4-DP
DPB
DPDM
DPH
DPM (or dpm)
DPMS
Dpp
DPPA
dppb
DPPC
DPP-Cl
dppe
Dppe
dppf
dppm
Dppm
dppp
DPS
DPSME
DPTC
DSAH
DSP
DSS
DSS
DSS
DST
DTBB
DTBMS
DTBP
DTBS
DTE
DTMC
DTNB
DTPA
Dts
DTT
DVB
DXE
E (or cathyl)

Organic Chemist's Desk Reference, Second Edition
(See DNF)
(See DNF)
5-Dimethylamino-1-naphthalenesulfonic acid
4,4′-Dinitrostilbene-2,2′-disulfonic acid, disodium salt
5-Dimethylaminonaphthalene-1-sulfonamide
N-Dansyl-3-aminobenzeneboronic acid
4-Dimethylamino-1-naphthyl isothiocyanate
Dioctyl adipate
p-(Dihydroxyboryl)benzyloxycarbonyl
Dioctyl phthalate
3,4-Dihydroxyphenethyl alcohol
2,4-Dichlorophenoxypropionic acid
1,4-Diphenyl-1,3-butadiene
Diphenyl diazomalonate
1,6-Diphenyl-1,3,5-hexatriene
Diphenylmethyl
Diphenylmethylsilyl
Diphenylphosphinyl
Diphenylphosphoryl azide
1,4-Bis(diphenylphosphino)butane
Dipalmitoylphophatidylcholine
Diphenylphosphinyl chloride
1,2-Bis(diphenylphosphino)ethane; see also DIPHOS
2-(Diphenylphosphino)ethyl
1,1′-bis(diphenylphosphino)ferrocene
Bis(diphenylphosphino)methane
Diphenyl-4-pyridylmethyl
1,3-Bis(diphenylphosphino)propane
trans-p,p′-Diphenylstilbene
2-(Methyldiphenylsilyl)ethyl
Di-2-pyridyl thionocarbonate
Disuccinimidyl (N,N′-diacetylhomocysteine)
Dithiobis(succinimidyl propionate)
2,2-Dimethyl-2-silapentane-5-sulfonate
3-(Trimethylsilyl)-1-propanesulfonic acid (sodium salt)
Disuccinimidyl suberate
Disuccinimidyl tartrate
4,4′-Di-tert-butylbiphenyl
Di-tert-butylmethylsilyl
Di-tert-butyl peroxide
Di-tert-butylsilylene
Dithioerythritol
4,4′-Dichloro-α-(trichloromethyl)benzhydrol
5,5′-Dithiobis(2-nitrobenzoic acid)
Diethylenetriaminepentaacetic acid
Dithiasuccininyl
Dithiothreitol
Divinylbenzene
Dixylylethane
Ethoxycarbonyl

Acronyms and Miscellaneous Terms Used in Describing Organic Molecules
EAA
EAA
EADC
EAK
EASC
EBA
EBASA
EBSA
ECEA
EDA
EDANS
EDB
EDC
EDCl (or EDC)
EDDP
EDTA (or edta)
EDTN
EDTP
EE
EEDQ
EGS
EGTA
en
EPN
EPPS
Et
ETA
ETSA
EVK
FA
FAMSO
Fc
FDMA
FDNB
FDNDEA
Fm
Fmoc
FNPS
For
Fp
FS
FTN
GABA
Glyme (glyme)
GLYMO
GUM
HABA
HABBA
HBD
HBT also HOBT

Ethyl acetoacetate
N-Ethylanthranilic acid
Ethylaluminium dichloride
Ethyl amyl ketone
Ethylaluminium sesquichloride
N-Ethyl-N-benzylaniline
N-Ethyl-N-benzylaniline-4-sulfonic acid
p-Ethylbenzenesulfonic acid
N-Ethyl-N-chloroethylaniline
Ethyl diazoacetate
2-Aminoethylamino-1-naphthalenesulfonic acid (1,5 or 1,8)
Ethylene dibromide
Ethylene dichloride
1-Ethyl-3-[3-(dimethylamino)propyl]carbodiimide hydrochloride
O-Ethyl S,S-diphenyl dithiophosphate
Ethylenediaminetetraacetic acid
1-Ethoxy-4-(dichloro-s-triazinyl)-naphthalene
Ethylenediamine tetrapropanol
1-Ethoxyethyl
N-Ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline
Ethylene glycol bis(succinimidyl succinate)
1,2-Bis(2-aminoethoxy)ethane-N,N,N′,N′-tetraacetic acid
Ethylenediamine
O-Ethyl O-(p-nitrophenyl)thiobenzenephosphate
4-(2-Hydroxyethyl)-1-piperazinepropanesulfonic acid
Ethyl
(See EDTA)
Ethyl trimethylsilylacetate
Ethyl vinyl ketone
Furfuryl alcohol
Methyl methylsulfinylmethyl sulfide
Ferrocenyl
Perfluoro-N,N-dimethylcyclohexylmethylamine
(See DNF)
5-Fluoro-2,4-dinitro-N,N-diethylaniline
9-Fluorenylmethyl
9-Fluorenylmethoxycarbonyl
Bis(4-fluoro-3-nitrophenyl) sulfone
Formyl
Cyclopentadienyl(dicarbonyl)ferrate
Fremy’s salt (dipotassium nitrosodisulfonate)
Perfluoro-1,3,7-trimethylbicyclo[3.3.1]nonane
4-Aminobutyric acid
1,2-Dimethoxyethane (see DME)
3-Glycidyloxypropyltrimethoxysilane
Guaiacolmethyl
2-(p-Hydroxyphenylazo)benzoic acid
2-(4′-Hydroxyazobenzene)benzoic acid
Hexabutyldistannoxane
1-Hydroxybenzotriazole

113

114
HDCBS
HDODA
HDPE
HEA
HEDTA
HEEI
HEMA
HEPES
HEPSO
HETE
Hex
HFA
HFBA
HFIP
HFP
HFTA
HHPA
HMAT
HMB
HMB
HMDS
HMDSO
HMI
HMN
HMPA
HMPT
HMPTA
HMTT
HOAt
HOBT also HBT
HONB
HOSA
HPETE
HPPH
HQ
HTMP
HVA
Hyiv
Hz
I-AEDANS
IBD
IBMX
IBTMO
IBX
ICl
IDTr
IIDQ
Im
IMds

Organic Chemist's Desk Reference, Second Edition
2-Hydroxy-3,5-dichlorobenzenesulfonic acid
1,6-Hexanediol diacrylate
High-density polyethylene
N-(2-Hydroxyethyl)aziridine
2-Hydroxyethylethylenediaminetriacetic acid
N-(2-Hydroxyethyl)ethyleneimine
2-Hydroxyethyl methacrylate
4-(2-Hydroxyethyl)-1-piperazineethanesulfonic acid
N-Hydroxyethylpiperazine-N′-2-hydroxypropanesulfinic acid
Hydroxy(e)icosatetraenoic acid
Hexane (or hexyl)
Hexafluoroacetone
Heptafluorobutyric acid
hexafluoroisopropyl alcohol
hexafluoropropene
hexafluorothioacetone
Hexahydrophthalic anhydride
Hexa[1-(2-methyl)aziridinyl]-1,3,5-triphorphatriazine
2-Hydroxy-5-methoxybenzaldehyde
2-Hydroxy-4-methoxybenzophenone
1,1,1,3,3,3-Hexamethyldisilazane
Hexamethyldisiloxane
Hexamethyleneimine
2,2,4,4,6,8,8-Heptamethylnonane
Hexamethylphosphoramide (hexamethylphosphoric triamide)
Hexamethylphosphorous triamide
(See HMPA)
3-Hexadecanoyl-4-methoxycarbonyl-1,3-thiazolidine-2-thione
1-Hydroxy-7-azabenzotriazole
1-Hydroxybenzotriazole
N-Hydroxy-5-norbornene-2,3-dicarboxylic acid imide
Hydroxylamine-O-sulfonic acid
Hydroperoxy(e)icosatetraenoic acid
5-Hydroxyphenyl-5-phenylhydantoin
Hydroquinone
4-Hydroxy-2,2,6,6-tetramethylpiperidine
Homovanillic acid (4-hydroxy-3-methoxyphenylacetic acid)
α-Hydroxyisovaleric acid
Homobenzyloxycarbonyl
N-Iodoacetyl-N′-(X-sulfo-1-naphthyl)ethylenediamine (X = 5, 1,5-I-AEDANS; X = 8,
1,8-I-AEDANS)
Iodobenzene dichloride
3-Isobutyl-1-methylxanthine
Isobutyltrimethoxysilane
2-Iodobenzoic acid
Isophthaloyl choride
3-(Imidazol-1-ylmethyl)-4,4′-dimethoxytriphenylmethyl
2-Isobutoxy-1-isobutoxycarbonyl-1,2-dihydroquinoline
1-Imidazolyl
2,6-Dimethoxy-4-methylbenzenesulfonyl

Acronyms and Miscellaneous Terms Used in Describing Organic Molecules
IMEO
INAH
INH
INT
IPA
Ipaoc
Ipc
IPC
IpcBH2
Ipc2BH
IPDI
IPDMS
IPN
IPOTMS
Ips
ITA
IZAA
KAPA
KBA
KBT
KDA
KDO
KHMDS
K-Selectride®
KS-Selectride®
LAH
LDA
LDBB (or LiDBB)
LDPE
Lev
LevS
Lgf2BH
LHMDS
LICA
LiHMDS
LiTMP
LPO
L-Selectride®
LS-Selectride®
LTA
LTMAC
LTMP
lut
M
MA
MAA
MAA
MABR
MAD
Mal

Imidazolinepropyltriethoxysilane
Isonicotinic acid hydrazide
(See INAH)
2-(p-Iodophenyl)-3-(p-nitrophenyl)-5-phenyltetrazolium chloride
Isopropyl alcohol
1-Isopropylallyloxycarbonyl
Isopinocampheyl
Isopropyl N-phenylcarbamate
Isopinocampheylborane
Bisisopinocampheylborane
Isophorone diisocyanate (3-isocyanatomethyl-3,4,4-trimethylcyclohexyl isocyanate
Isopropyldimethylsilyl
Isophthalonitrile
Isopropenyloxytrimethylsilane
[(4-Iodophenyl)sulfonyl]
Itaconic anhydride
5-Chloroindazol-3-acetic acid ethyl ester
Potassium 3-aminopropylamide
3-Ketobutyraldehyde dimethyl acetal
4-Ketobenztriazine
Potassium diisopropylamide
2-Keto-3-deoxyoctonate
Potassium hexamethyldisilazanide
Potassium tri-sec-butylborohydride
Potassium triisoamylborohydride
Lithium aluminium hydride
Lithium diisopropylamide
Lithium 4,4′-di-tert-butylbiphenylide
Low-density polyethylene
Levulinoyl (4-oxopentanoyl)
[4,4-(Ethylenedithio)pentanoyl]
Dilongifolylborane
Lithium hexamethyldisilazane
Lithium isopropylcyclohexylamide
Lithium hexamethyldisilazanide
Lithium tetramethylpiperidide
Lauroyl peroxide
Lithium tri-sec-butylborohydride
Lithium triisoamylborohydride
Lead tetraacetate
Dodecyltrimethylammonium chloride
Lithium 2,2,6,6-tetramethylpiperidide
Lutidine
Metal
Maleic anhydride
Menthoxyacetic acid
Methyl acetoacetate
Methylaluminium bis(4-bromo-2,6-di-tert-butylphenoxide)
Methylaluminium bis(2,6-di-tert-butyl-4-methylphenoxide)
Maleyl

115

116
-MalMAM-acetate
MAPO
MAPS
MAPTAC
MASC
MBA
MBBA
MBE
MBF
MBS
MBS
MBTH
3-MC
MCA
MCAA
3,3-MCH
MCPBA (or m-CPBA)
MCPCA
MCPDEA
MCPP
MDA
MDEB
Mds
Me
MeCCNU
MEI
MEK
MEM
MEMCl
MEMO
MeOTf
1-MEO-PMS
MeOZ
MEP
Mes
MES-hydrate
Meth
MG-Ch
MHHPA
MIA
MIBK
MICA
MIPK
MIX
MMA
MMAA
MMC
MMF
MMH

Organic Chemist's Desk Reference, Second Edition
Maleoyl
Methylazoxymethyl acetate
Tris[1-(2-methyl)aziridinyl]phosphine
Tris[1-(2-methyl)aziridinyl]phosphine sulfide
Methacrylamidopropyltrimethylammonium chloride
Methylaluminium sesquichloride
N,N′-Methylenebisacrylamide
N-(p-Methoxybenzylidene)-p-butylaniline
1-Methyl-1-benzyloxyethyl
2,3,3a,4,5,6,7,7a-Octahydrotrimethyl-4,7-methanobenzofuran-2-yl
m-Maleimidobenzoyl-N-hydroxysuccinimide ester
p-Methoxybenzenesulfonyl
3-Methyl-2-benzothiazolinone hydrazone
3-Methylcholanthrene
Monochloroacetic acid
(See MCA)
3-Methyl-3-cyclohexen-1-one
3-Chloroperoxybenzoic acid (m-chloroperoxybenzoic acid)
2-Methyl-4-chlorophenoxyaceto-o-chloroanilide
N,N-Di(2-hydroxyethyl)-m-chloroaniline
4-Chloro-3-methylphenoxypropionic acid
1,8-p-Menthanediamine
N-Methyl-N-dodecylephedrinium bromide
2,6-Dimethyl-4-methoxybenzenesulfonyl
Methyl
1-(2-Chloroethyl)-3-(4-trans-methylcyclohexyl)-1-nitrosourea
2-Morpholinoethyl isocyanide
Methyl ethyl ketone
2-Methoxyethoxymethyl
2-Methoxyethoxymethyl chloride
3-Methacryloxypropyltrimethoxysilane
Methyl trifluoromethanesulfonate
1-Methoxy-5-methylphenazinium methyl sulfate
p-Methoxybenzyloxycarbonyl
O,O-Dimethyl O-(3-methyl-4-nitrophenyl) phosphorothioate
Mesityl (2,4,6-trimethylphenyl)
4-Morpholineethanesulfonic acid
2-Mercaptoethanol
Methyl glycol chitosan
4-Methylhexahydrophthalic anhydride
N-Methylisatoic anhydride
Methyl isobutyl ketone
Magnesium isopropyl cyclohexamide
Methyl isopropyl ketone
3-Isobutyl-1-methylxanthine
Methyl methacrylate
Mono-N-methylacetoacetamide
Methyl magnesium carbonate
N-Monomethylformamide
Methyl mercuric hydroxide

Acronyms and Miscellaneous Terms Used in Describing Organic Molecules
MMS
MMTr
MMTrCl
MMTS
MNA
MNNG
MNPT
MOM
MOMCl
MoOPH
MOP
MOPS
MOPSO
Moz
MP
MPEMA
MPM (or PMB)
MPP
MPPH
Mps
MPS
Mpt
Mpt-Cl
MRITC
Ms (or MS)
MSA
bis-MSB
MsCl
MSE
MSH
Msib
MSMA
MSO
MSOC
MsOH
MST
MSTFA
Msz
Mtb
MTBE
MTBSTFA
MTCA
MTD
MTDEA
Mte
MTES
MTH
MTHP
MTHPA
MTM

Methyl methanesulfonate
Monomethoxytrityl (4-methoxyphenyldiphenylmethyl)
Monomethoxytrityl chloride
(See FAMSO)
Methylnadic anhydride (methylnorbornene-2,3-dicarboxylic acid anhydride)
N-Methyl-N′-nitro-N-nitrosoguanidine
m-Nitro-p-toluidine
Methoxymethyl
Chloromethyl methyl ether
Oxodiperoxymolybdenum(pyridine) hexamethylphosphoramide (MoO5∙Py∙HMPA)
2-Methoxy-2-propyl
4-Morpholinepropanesulfonic acid
3-(N-Morpholino)-2-hydroxypropanesulfonic acid
4-Methoxybenzyloxycarbonyl
4-Methoxyphenyl
2-Ethyl-2-(p-tolyl)malonamide
(4-Methoxyphenyl)methyl (p-methoxybenzyl)
O,O-Dimethyl O-(4-methylmercapto-3-methylphenyl) thiophosphate
5-(p-Methylphenyl)-5-phenylhydantoin
4-Methoxyphenylsulfonyl
Methyl phenyl sulfide
Dimethylthiophosphinyl
Methylphosphinothionyl chloride
Methylrhodamine isothiocyanate
Mesyl (methanesulfonyl)
Methanesulfonic acid
4-Bis(2-methylstyryl)benzene
Methanesulfonyl chloride
2-(Methylsulfonyl)ethyl
2,4,6-Trimethylbenzenesulfonyl hydrazide
4-(Methylsulfinyl)benzyl
Monosodium methanearsonate
4-Cresyl methyl ether
N-(2-Methylsulfonyl)ethyloxycarbonyl
Methanesulfonic acid
Mesitylenesulfonyltetrazolide
N-Methyl-N-trimethylsilyltrifluoroacetamide
4-Methylsulfonylbenzyloxycarbonyl
2,4,6-Trimethoxybenzenesulfonyl
Methyl tert-butyl ether (tert-butyl methyl ether)
N-(tert-Butyldimethylsilyl)-N-methyltrifluoroacetamide
2-Methylthiazolidine-4-carboxylic acid
m-Toluenediamine
N,N-Di(2-hydroxyethyl)-m-toluidine (m-toluidine-N,N-diethanol)
2,3,5,6-Tetramethyl-4-methoxybenzenesulfonyl
Methyltriethoxysilane
Methylthiohydantoin
4-Methoxytetrahydropyranyl
Methyltetrahydrophthalic anhydride
Methylthiomethyl

117

118
MTMB
MTMC
MTMECO
MTMS
MTMT
MTN
MTP
MTPA
Mtpc
Mtr
Mts
MTT
MTX
MUGB
MVK
MVP
MXDA
5-NAA
NAC
NaHMDS
NAP
Naph
NB
NBA
nbd
NBDCl
NBD-F
NBMPR
NBS
Nbs
NBSac
NBSC
NCA
NCDC
NCN
NCS
NEM
NEP
NEPIS
NesMIC
Nf
5-NIA
NHS
NIP
NIP
NIS
NM
NMA
NMM
NMM

Organic Chemist's Desk Reference, Second Edition
4-(Methylthiomethoxy)butanoyl
4-(Methylthio)-m-cresol
2-(Methylthiomethoxy)ethoxycarbonyl
Methyltrimethoxysilane
2-(Methylthiomethoxymethyl)benzoyl
m-Tolunitrile
4-(Methylthio)phenol
α-Methoxy-α-trifluoromethylphenylacetic acid
4-Methylthiophenoxycarbonyl
4-Methoxy-2,3,6-trimethylphenylsulfonyl
2,4,6-Trimethylbenzenesulfonyl
3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide
Methotrexate
4-Methylumbelliferyl p-guanidinobenzoate
Methyl vinyl ketone
2-Methyl-5-vinylpyridine
m-Xylylenediamine
5-Nitroanthranilic acid
1-Naphthyl N-methylcarbamate
Sodium hexamethyldisilazanide
2-Naphthylmethyl
2-Naphthyl
p-Nitrobenzyl
N-Bromoacetamide
Norbornadiene (bicyclo[2.2.1]hepta-2,5-diene)
4-Chloro-7-nitro-2,1,3-benzoxadiazole
7-Fluoro-4-nitro-2,1,3-diazole
S-(p-Nitrobenzyl)-6-thioinosine
N-Bromosuccinimide
[(3-Carboxy-4-nitrophenyl)thio]
N-Bromosaccharin
2-Nitrobenzenesulfenyl chloride
N-Chloroacetamide
2-Nitro-4-carboxyphenyl N,N-diphenylcarbamate
Cyanonaphthalene
N-Chlorosuccinimide
N-Ethylmaleimide
N-Ethyl-2-pyrrolidinone
N-Ethyl-5-phenylisoxazolium-3′-sulfonate
(+)-(Neomenthylsulfonyl)methyl isocyanide
Nonaflyl (perfluoro-1-butanesulfonyl) or nonaflate
5-Nitroisatoic anhydride
N-Hydroxysuccinimide
2,4-Dichlorophenyl 4′-nitrophenyl ether
4-Hydroxy-5-nitro-3-iodophenyl acetic acid
N-Iodosuccinimide
Nitromethane
N-Methylolacrylamide
N-Methylmaleimide
N-Methylmorpholine

Acronyms and Miscellaneous Terms Used in Describing Organic Molecules
NMO (or NMMO)
NMP
NMP
NMP
NMSO
Noc
NORPHOS
NP
Npe
NPM
α-NPO
NPP
NPS
NPSP
Npys-Cl
Ns
N-Selectride®
NTA
N-t-B
OBO
OCAD
OCBA
OCBC
OCBN
OCCN
OCDC
OCOC
OCPA
OCPT
OCT
OCTC
OCTEO
ODA
OMH-1
ONB
OTB
OTD
PABA
PADA
PADA
PAH
PAH
PAM
2-PAM
2-PAMCl
PAN
PAP
PAPA
p-APMSF
PAS

N-Methylmorpholine N-oxide
N-Methylphthalimide
N-Methyl-2-pyrrolidone
N-Methylpyrrolidin-2-one
4-Methyl-2-nitroanisole
4-Nitrocinnamyloxcarbonyl
Bis(diphenylphosphino)bicyclo[2.2.1]hept-5-ene
2-(or 4-)Nitrophenyl
2-(4-Nitrophenyl)ethyl
N-Phenylmaleimide
2-(1-Naphthyl)-5-phenyloxazole
2-Nitro-2-propenyl pivalate
o-Nitrophenylsulfenyl
N-Phenylselenylphthalimide
3-Nitro-2-pyridinesulfenyl chloride
2-(or 4-)Nitrophenylsulfonyl
Sodium tri-sec-butylborohydride
Nitrilotriacetic acid
2-Methyl-2-nitropropane
4-Methyl-2,6,7-trioxabicyclo[2.2.2]octane
o-Chlorobenzaldehyde
o-Chlorobenzoic acid
o-Chlorobenzyl chloride
o-Chlorobenzonitrile
o-Chlorobenzyl cyanide
o-Chlorodichlorotoluene
o-Chlorobenzoyl chloride
o-Chlorophenylacetic acid
2-Chloro-4-aminotoluene (o-chloro-p-aminotoluene)
o-Chlorotoluene
o-Chlorobenzotrichloride
Octyltriethoxysilane
4,4′-Oxydianiline
Sodium diethylhydroaluminate
o-Nitrobenzyl
o-Toluidine boric acid
o-Toluenediamine
p-Aminobenzoic acid
Poly(adipic anhydride)
Pyridine-2-azo-p-dimethylaniline
p-Aminohippuric acid
Polycyclic aromatic hydrocarbon
Pyridine-2-aldoxime methiodide
(See PAM)
2-Pyridinealdoxime methochloride
1-(2-Pyridylazo)-2-naphthol
O,O-Dimethyl S-α-(ethoxycarbonyl)benzyl phosphorothiolothioate
Poly(azelaic anhydride)
(p-Amidinophenyl)methylsulfonylfluoride
p-Aminosalicylic acid

119

120
PASAM
PBA
PBB
PBBO
PBD
PBI
PBN
PBP
PBS
PBz
PC
PCAD
PCB
p-CBA
PCBA
PCBC
PCBN
PCBTF
PCC
PCCN
PCDC
P-Cellulose
PCMB
PCMX
PCNB
PCOC
PCONA
PCOT
PCP
PCPA
PCT
PCT
PCTC
PDC
PDEA
PDQ
PDT
PEA
PEEA
PEEK
PEG
PEI-cellulose
PEMA
Peoc
Peoc
PEP
Pet
PET
PETA
Pfp

Organic Chemist's Desk Reference, Second Edition
p-Toluenesulfonamide
p-Benzoquinone-2,3-dicarboxylic anhydride
p-Bromobenzyl
2-(4-Biphenylyl)-6-phenylbenzoxazole
2-(4-Biphenylyl)-5-phenyl-1,3,4-oxadiazole
p-Benzoquinone-2,3-dicarboxylic imide
N-tert-Butyl-α-phenylnitrone
p-(Benzyloxy)phenol
Poly(butene-1-sulfone)
p-Phenylbenzoyl
Propylene carbonate
p-Chlorobenzaldehyde
p-Chlorobenzyl
p-Carboxybenzaldehyde
p-Chlorobenzoic acid
p-Chlorobenzyl chloride
p-Chlorobenzonitrile
p-Chlorobenzotrifluoride
Pyridinium chlorochromate
p-Chlorobenzyl cyanide
p-Chlorodichlorotoluene
Cellulose phosphate
p-Chloromercuribenzoic acid
p-Chloro-m-xylenol
Pentachloronitrobenzene
p-Chlorobenzoyl chloride
p-Chloro-o-nitroaniline
4-Chloro-2-aminotoluene (p-chloro-o-aminotoluene)
Pentachlorophenol
p-Chlorophenylacetic acid
p-Chlorotoluene
Polychloroterphenyl
p-Chlorobenzotrichloride
Pyridinium dichromate
N-Phenyldiethanolamine
Sodium (2-methyl-4-chlorophenoxy)butyrate
3-(2-Pyridyl)-5,6-diphenyl-1,2,4-triazine
N-(2-Hydroxyethyl)aniline (N-phenylethanolamine)
N-(2-Hydroxyethyl)-N-ethylaniline (N-phenyl-N-ethylethanolamine)
Poly(ether ether ketone)
Poly(ethylene glycol)
Polyethyleneimine-impregnated cellulose
2-Ethyl-2-phenylmalonamide
2-Phosphonioethoxycarbonyl
2-(Triphenylphosphonio)ethoxycarbonyl
Phosphoenolpyruvic acid
2-(2′-Pyridyl)ethyl
Poly(ethylene terephthalate)
Pentaerythritol triacrylate
Pentafluorophenyl

Acronyms and Miscellaneous Terms Used in Describing Organic Molecules
PG
PGE
Ph
Phenoc
Phenyl-MAPO
Pht
Phth
PhthN
PIA
PIPES
Pixyl (or Px)
PMA
PMB (or MPM)
PMBCl
PMBM
PMBOH
Pmc
PMDTA
Pme
PMEA
PMH
PMHS
PMI
PMI-ACID
PMP
PMS
PMS
PNASA
PNB
PNMT
PNOT
PNPDPP (p-NPDPP)
PNPG
PNPP
PNZ
4-POBN
POBN
POC
POM
POM
POM (or Pom)
POPOP
POPSO
PPA
PPDA
PPDP
PPE
PPNCl
PPO
Ppoc

Protective group
Phenyl glycidyl ether
Phenyl
4-Methoxyphenacyloxycarbonyl
Bis[1-(2-methyl)aziridinyl]phenylphosphine oxide
Phthalyl
Phthaloyl
Phthalimido
Phenyliodoso diacetate
1,4-Piperazinebis(ethanesulfonic acid)
9-Phenyl-9-xanthenyl
Phenylmercuric acetate
4-Methoxybenzyl (p-methoxybenzyl)
p-Methoxybenzyl chloride
p-Methoxybenzyloxymethyl
p-Methoxybenzyl alcohol
2,2,5,7,8-Pentamethylchroman-6-sulfonyl
Pentamethyldiethylenetriamine
Pentamethylbenzenesulfonyl
N-(2-Hydroxyethyl)-N-methylaniline (N-phenyl-N-methylethanolamine)
Phenylmercuric hydroxide
Polymethylhydrosiloxane
3-Phenyl-5-methylisoxazole
3-Phenyl-5-methylisoxazole-4-carboxylic acid
p-Methoxyphenyl
p-Methylbenzylsulfonyl
Phenazine methosulfate
p-Nitroaniline-o-sulfonic acid
p-Nitrobenzyl
Phenylethanolamine-N-methyltransferase
p-Nitro-o-toluidine
p-Nitrophenyl diphenyl phosphate
α-p-Nitrophenylglycerine
p-Nitrophenyl phosphate
p-Nitrobenzyloxycarbonyl
(See POBN)
α-(4-Pyridyl-1-oxide)-N-tert-butylnitrone
Cyclopentyloxycarbonyl
Chloromethyl pivalate
4-Pentenyloxymethyl
Pivaloyloxymethyl
1,4-Bis(5-phenyloxazol-2-yl)benzene
Piperazine-N,N′-bis(2-hydroxypropanesulfonic acid)
Polyphosphoric acid
Phenyl phosphorodiamidate
p,p′-Diphenol
Polyphosphate ester
Bis(triphenylphosphoranylidene)ammonium chloride
2,5-Diphenyloxazole
2-Triphenylphosphonioisopropoxycarbonyl

121

122
Ppt
PPTS
4-Ppy
Pr
iPr
Proton sponge
P2S
PS-Cl
Psec
Psoc
PSPA
PTAD
PTAP
PTBBA
Ptc
PTC
PTC
PTH
PTM
PTMO
PTSA
PTSI
Pv
PVA
PVC
PVDF
PVP
PVPDC
PVP-I
PVSK
Px
py (or Py or Pyr)
Pyoc
PyOTs
Pz
Qu
QUIBEC
RAMP
RDB
Red-Al
RNA
SAA
SADP
salen
SAMP
SBH
Scm
SDP
SDPP

Organic Chemist's Desk Reference, Second Edition
Diphenylthiophosphinyl
Pyridinium 4-toluenesulfonate
4-Pyrrolidinopyridine
Propyl
Isopropyl
1,8-Bis(dimethylamino)naphthalene
2-Pyridinealdoxime methyl methanesulfonate
2-Pyridinesulfenyl chloride
2-(Phenylsulfonyl)ethoxycarbonyl
2-Phenyl-2-(trimethylsilyl)ethoxycarbonyl
Poly(sebacic anhydride)
N-Phenyl-1,2,4-triazoline-3,5-dione
Phenyltrimethylammonium perbromide
p-tert-Butylbenzoic acid
Phenyl(thiocarbamoyl)
Phase transfer catalyst
Phenyl isothiocyanate
Phenylthiohydantoin
Phenylthiomethyl
Propyltrimethoxysilane
p-Toluenesulfonic acid
p-Toluenesulfonyl isocyanate
Pivaloyl
Poly(vinyl alcohol)
Poly(vinyl chloride)
Poly(vinylidene fluoride)
Polyvinylpyrrolidone
Poly(4-vinylpyridinium) dichromate
Polyvinylpyrrolidone-iodine complex
Potassium poly(vinyl sulfate)
(See Pixyl)
Pyridine
2-(Pyridyl)ethoxycarbonyl
(See PPTS)
4-Phenylazobenzyloxycarbonyl
8-Quinolinyl
Benzylquinidinium chloride
(R)-1-Amino-2-(methoxymethyl)pyrrolidine
Sodium dihydrobis(2-methoxyethoxy)aluminate (sodium bis(2-methoxyethoxy)aluminium
hydride)
Sodium bis(2-methoxyethoxy)aluminium hydride
Ribonucleic acid
Succinic anhydride
N-Succinimidyl (4-azidophenyldithio)propionate
Bis(salicylidene)ethylenediamine
(S)-1-Amino-2-(methoxymethyl)pyrrolidine
Sodium borohydride
S-Carboxymethylsulfenyl
4,4′-Sulfonyldiphenol
N-Succinimidyl diphenyl phosphate

Acronyms and Miscellaneous Terms Used in Describing Organic Molecules
SDS
SDS
SEM
SEMCl
SES
SESNHBoc
SEX
Sia2BH
SLS
SMCC
SMOM
SMPB
Snm
SPA
SPADNS
SPDP
SSP
STABASE
STPP
STr
Su
Suc
-SucSuper-Hydride®
2,4,5-T
TAC
Tacm
TAMA
TAME
TAMM
TAPA
TAPS
TAPSO
TAS
TASF (or TAS-F)
TB
2,3,6-TBA
TBAB
TBAC
TBACl
TBAF
TBAHS
TBAI
TBAP
TBAS
TBC
TBDA
t-BDEA
TBDMS (or TBS)
TBDMSCl (or TBSCl)

Sodium dodecyl benzenesulfonate
Sodium dodecyl sulfate
2-(Trimethylsilyl)ethoxymethyl
2-(Trimethylsilyl)ethoxymethyl chloride
2-(Trimethylsilyl)ethylsulfonyl
tert-Butyl 2-(trimethylsilyl)ethanesulfonyl carbamate
Sodium ethyl xanthate
Disiamylborane
Sodium lauryl sulfate
Succinimidyl 4-(N-maleimidomethylcyclohexane)-1-carboxylate
(Phenyldimethylsilyl)ethoxymethyl
Succinimidyl 4-(p-maleimidophenyl)butyrate
S-(N-Methyl-N-phenylcarbamoyl)sulfenyl
Superphosphoric acid
2-(p-Sulfophenylazo)-1,8-dihydroxy-3,6-naphthalenedisulfonic acid (trisodium salt)
N-Succinimidyl 3-(2-pyridyldithio)propionate
1,2-Distearoylpalmitin
1,1,4,4-Tetramethyldisilylazacyclopentane
Sodium tripolyphosphate
Triphenylmethanesulfenyl
Succinimido
3-Carboxypropanoyl
Succinyl
Lithium triethylborohydride
2,4,5-Trichlorophenoxyacetic acid
Triallyl cyanurate
Trimethylacetamidomethyl
N-Methylanilinium trifluoroacetate
N-α-p-Tosyl-l-arginine methyl ester hydrochloride
tetrakis(acetoxymercuri)methane
α-(2,4,5,7-Tetranitro-9-fluorenylideneaminooxy)propionic acid
3-[Tris(hydroxymethyl)methylamino]-1-propanesulfonic acid
3-[N-(Tris(hydroxymethyl)methylamino]-2-hydroxypropanesulfonic acid
Tris(diethylamino)sulfonium
Tris(dimethylamino)sulfonium (trimethylsilyl)difluoride
Thexylborane
2,3,6-Trichlorobenzoic acid
Tetrabutylammonium bromide
tert-Butylacetyl chloride
Tetrabutylammonium chloride
Tetrabutylammonium fluoride
Tetrabutylammonium hydrogen sulfate
Tetrabutylammonium iodide
Tetra-n-butylammonium perchlorate
Tetra-n-butylammonium succinimide
p-tert-Butylcatechol
Thexylborane-N,N-diethylaniline
tert-Butyldiethanolamine
tert-Butyldimethylsilyl
tert-Butyldimethylsilyl chloride

123

124
TBDMSI
TBDPS
TBDS
TBE
TBHC
TBHP
TBMPS
TBO
TBP
TBP
TBPB
TBS
TBSCl
TBSOTf
TBTD
TBTr
tBu
t-BuOK
TBUP
TC
TCA
TCB
TCB
TcBoc
TCE (or Tce)
Tcec also Troc
TcecCl also TrocCl
TCl
TCNE
TCNP
TCNQ
TCP
TCP (or Tcp)
TCP
Tcroc
Tcrom
TCTFP
TDI
TDP
TDS
TEA
TEA
TEA
TEAB
TEAE-cellulose
TEAS
TEBA (or TEBAC)
TEBAB
TED
TEG

Organic Chemist's Desk Reference, Second Edition
1-(tert-Butyldimethylsilyl)imidazole
tert-Butyldiphenylsilyl
Tetra-tert-butoxydisilane-1,3-diylidene
1,1,2,2-Tetrabromoethane
tert-Butyl hypochlorite
tert-Butyl hydroperoxide
tert-Butylmethoxyphenylsilyl
3-[(Trimethylsilyl)oxy]-3-buten-2-one
Tri-n-butyl phosphate
Triphenylbutylphosphonium bromide
tert-Butylbenzoyl peroxide
(See TBDMS)
(See TBDMSCl)
tert-Butyldimethylsilyl triflate
Tetrabutylthiuram disulfide
4,4′,4″-Tris(benzyloxy)triphenylmethyl
tert-Butyl
Potassium tert-butoxide
Tri-n-butylphosphine
2,3,4,5-Tetraphenylcyclopentadienone
Trichloroacetic acid
Trichlorobenzene (usually 1,3,5)
2,2,2-Trichloro-1,1-dimethylethyl
1,1-Dimethyl-2,2,2-trichloroethoxycarbonyl
2,2,2-Trichloroethyl
2,2,2-Trichloroethoxycarbonyl
2,2,2-Trichloroethoxycarbonyl chloride (2,2,2-trichloroethyl chloroformate)
Terephthaloyl chloride
Tetracyanoethene (tetracyanoethylene)
11,11,12,12-Tetracyanopyreno-2,7-quinodimethane
7,7,8,8-Tetracyanoquinodimethane
Tetrachlorophthaloyl
Trichlorophenol (usually 2,4,5 or 2,4,6)
Tricresyl phosphate
2-(Trifluoromethyl)-6-chromonylmethylenecarbonyl
2-(Trifluoromethyl)-6-chromonylmethylene
1,1,2,2-Tetrachloro-3,3,4,4-tetrafluorocyclobutane
Tolylene diisocyanate
4,4′-Thiodiphenol
Thexyldimethylsilyl
Triethanolamine
Triethylaluminium
Triethylamine
Triethylammonium bicarbonate
Triethylaminoethyl cellulose
Tetraethylammonium succinimide
Benzyltriethylammonium chloride
Triethylbenzylammonium bromide
(See DABCO)
Triethylene glycol

Acronyms and Miscellaneous Terms Used in Describing Organic Molecules
TEM
TEMPO
Teoc
TES
TES
TES
TESOTf
TETD
TETM
Tf
TFA
TFA
TFAA
TFA-ME
TFE
TFMC-Eu
TFMC-Pr
TfOH
THAM
THF
THFA
THFC-Eu
THIP
THP
Thx
TIBA
TIBA
TIPDS
TIPS
TLCK
TLTr (or TLT)
TMA
TMAC
TMAEMC
TMANO
TMAT
TMAT
TMB
TMB
TMB (or Tmob)
TMB-4
TMBA
TMC
TMCS
TMEDA
TMM
TMO
TMP
TMPM
TMPTA

Triethylenediamine (1,4-diazabicyclo[2.2.2]octane)
2,2,6,6-Tetramethylpiperidinyloxy
2-(Trimethylsilyl)ethoxycarbonyl
N,N,N′,N′-Tetraethylsulfamide
Triethylsilyl
2-[Tris(hydroxymethyl)methylamino]-1-ethanesulfonic acid
Triethylsilyl triflate
Tetraethylthiuram disulfide
Tetraethylthiuram monosulfide
Trifluoromethanesulfonyl (triflyl)
Trifluoroacetic acid
Trifluoroacetyl
Trifluoroacetic anhydride
Methyl trifluoroacetate
2,2,2-Trifluoroethanol
Tris[3-(trifluoromethylhydroxymethylene)-d-camphorato]∙Eu(III)
Tris[3-(trifluoromethylhydroxymethylene)-d-camphorato]∙Pr(III)
Trifluoromethanesulfonic acid
Tris(hydroxymethyl)aminomethane
Tetrahydrofuran, tetrahydrofuranyl
Tetrahydrofurfuryl alcohol
Tris[3-(heptafluoropropylhydroxymethylene)-d-camphorato]∙Eu(III)
4,5,6,7-Tetrahydroisoxazolo[5,4-c]pyrimidin-3(2H)-one
Tetrahydropyran (or tetrahydropyranyl)
Thexyl (2,3-dimethyl-2-butyl)
Triiodobenzoic acid (usually 2,3,5)
Triisobutylaluminium
1,3-(1,1,3,3-Tetraisopropyldisilanoxylidene)
Triisopropylsilyl
1-Chloro-3-tosylamido-7-amino-2-heptanone hydrochloride
4,4′,4″-Tris(levulinoyloxy)triphenylmethyl
Trimethylaluminium
Trimellitic anhydride monoacid chloride
2-Trimethylammoniumethylmethacrylic chloride
Trimethylamine N-oxide
Tetramethylammonium tribromide
Tris-2,4,6-[1-(2-methyl)aziridinyl]-1,3,5-triazine
3,3′,5,5′-Tetramethylbenzidine
N,N,N′,N′-Tetramethylbenzidine
2,4,6-Trimethoxybenzyl
1,1′-Trimethylenebis[4-(hydroxyiminomethyl)pyridinium bromide]
3,4,5-Trimethylbenzaldehyde
3,3,5-Trimethylcyclohexanol
(See TMSCl)
N,N,N′,N′-Tetramethylethylenediamine
Trimethylenemethane
Trimethylamine N-oxide
2,2,6,6-Tetramethylpiperidine
Trimethoxyphenylmethyl
Trimethylolpropane triacrylate

125

126
TMPTMA
TMS
TMS
TMSCl
TMSCN
TMSDEA
TMSE
TMSEC
TMSI
TMSIM
TMSOTf
TMTD
TMTM
TMTr (or TMT)
TNBA
TNF
TNM
TNPA
TNS
TNT
Tol
TOPO
TOS
TosMIC (or TOSMIC)
TPAP
TPB
TPCD
TPCK
TPE
TPP
TPP
TPP
TPPTS
TPS
TPS
TPS
TPSCl
TPSCl (or TPS)
TPTZ
Tr
TRIAMO
Tricine
Triglyme
Tris
trien
TRITC
Troc
TrocCl
TRPGDA
TrS

Organic Chemist's Desk Reference, Second Edition
Trimethylolpropane trimethacrylate
Tetramethylsilane
Trimethylsilyl
Trimethylsilyl chloride
Trimethylsilyl cyanide
N,N-Diethyl-1,1,1-trimethylsilylamine
2-(Trimethylsilyl)ethyl
2-(Trimethylsilyl)ethoxycarbonyl
Trimethylsilyl iodide
1-(Trimethylsilyl)imidazole
Trimethylsilyl trifluoromethanesulfonate (triflate)
Tetramethylthiuram disulfide
Tetramethylthiuram monosulfide
Tris(p-methoxyphenyl)methyl (trimethoxytrityl)
Tri-n-butylaluminium
2,4,7-Trinitrofluorenone
Tetranitromethane
Tri-n-propylaluminium
6-(p-Toluidino)-2-naphthalenesulfonic acid, potassium salt
2,4,6-Trinitrotoluene
4-Tolyl (4-methylphenyl)
Tri-n-octylphosphine oxide
p-Toluenesulfonyl (tosyl)
Tosylmethyl isocyanide
Tetra-n-propylammonium perruthenate
1,1,4,4-Tetraphenyl-1,3-butadiene
Tetraphenylcyclopentadienone
l-1-p-Tosylamino-2-phenylethyl chloromethyl ketone
Tetraphenylethylene
Tetraphenylporphyrin
Triphenyl phosphate
Triphenylphosphine
Trisodium 3,3′,3″-phosphinetriyltribenzenesulfonate
2,4,6-Triisopropylbenzenesulfonyl
Triphenylsilyl
Triphenylsulfonium chloride
1,3-Dichloro-1,1,3,3-tetraisopropyldisiloxane
2,4,6-Triisopropylbenzenesulfonyl chloride
2,4,6-Tris(2-pyridyl)-s-triazine triaminosilane
Trityl (triphenylmethyl)
Triaminosilane
N-[Tris(hydroxymethyl)methyl]glycine
Triethylene glycol dimethyl ether
Tris(hydroxymethyl)aminomethane
Triethylenetetramine
Tetramethylrhodamine isothiocyanate
2,2,2-Trichloroethyloxycarbonyl
2,2,2-Trichloroethyl chloroformate; see also TcecCl
Tripropylene glycol diacrylate
Triphenylmethanesulfenyl

Acronyms and Miscellaneous Terms Used in Describing Organic Molecules
TrtF7
Ts
Tse
Tsoc
TSIM
TSNI
TsOH
TTC
TTEGDA
TTF
TTFA
TTN

2,3,4,4′,4″,5,6-Heptafluorotriphenylmethyl
Tosyl (or p-toluenesulfonyl)
2-p-Toluenesulfonylethyl
2-(p-Toluenesulfonyl)ethoxycarbonyl
N-Trimethylsilylimidazole
1-(p-Toluenesulfonyl)-4-nitroimidazole
4-Toluenesulfonic acid
2,3,5-Triphenyltetrazolium chloride
Tetraethylene glycol diacrylate
Tetrathiafulvalene
Thallium(III) trifluoroacetate
Thallium(III) nitrate

UDMH
VMA
Voc
VTC
VTEO
VTMO
VTMOEO
Xan
Xy
Z
Z(Br)
Z(NO2)
Z(OMe)
ZDBC
ZDEC
ZDMC
ZPCK

unsym-Dimethylhydrazine
4-Hydroxy-3-methoxymandelic acid (vanillomandelic acid)
Vinyloxycarbonyl
Vinyltrichlorosilane
Vinyltriethoxysilane
Vinyltrimethoxysilane
Vinyltris(2-methoxyethoxy)silane
9H-Xanthen-9-yl
Xylene
Benzyloxycarbonyl; see also CBz and CBn
4-Bromobenzyloxycarbonyl
4-Nitrobenzyloxycarbonyl
4-Methoxybenzyloxycarbonyl
Zinc dibutyldithiocarbamate
Zinc diethyldithiocarbamate
Zinc dimethyldithiocarbamate
N-CBZ-l-Phenylalanine chloromethyl ketone

127

6.2 Glossary of Miscellaneous Terms and Techniques Used
in Nomenclature, Including Colloquial Terms
abeo-: Used in terpenoid and steroid nomenclature to indicate that a bond has migrated. For example, in a 5(4→3)abeo-terpene, the 5–4 bond has been replaced by a 5–3 bond contracting
ring A from six to five members.

2
3

1
4

H
normal triterpene

2
3

1
5

H
5(4

3)-abeo-triterpene

-acene: The names of polycyclic aromatic hydrocarbons containing five or more fused benzene
rings in a straight linear arrangement are formed by a numerical prefix followed by -acene.

hexacene

128

Organic Chemist's Desk Reference, Second Edition

acetals: Diethers of gem-diols R2C(OR)2 (R can be the same or different). Often named as derivatives of aldehydes or ketones. Thus, acetaldehyde dimethyl acetal is H3CCH(OMe)2. It is
now more usual to name them as dialkoxy compounds, e.g., 1,1-dimethoxyethane. The
term acetal is sometimes extended to compounds containing heteroatoms other than oxygen, as in N,O-acetals R2C(OR)(NR2). Derivatives of ketones can be called ketals. This
term was abandoned by IUPAC but has been reinstated.
acetonides: Cyclic acetals derived from acetone and diols. Better described as isopropylidene
derivatives.
HO

O
O

glycerol acetonide =
1,2-isopropylidene glycerol =
2,2-dimethyl-1,3-dioxolane-4-methanol(CAS)

acetylenes: A general term for hydrocarbons having one or more triple bonds. Alkynes is now the
more usual term. Acetylene itself is HC≡CH.
acetylides: Metal derivatives of acetylene. Sodium acetylide is HC≡CNa.
aci-: The acid form of (prefix).
acid anhydrides: See anhydrides.
acid halides: See acyl halides.
acylals: General term for diesters of gem-diols. They are named as esters. Thus, H3CCH(OAc)2 is
ethylidene diacetate.
acyl halides (acid halides): General term for compounds in which the hydroxy group of an acid
is replaced by a halogen atom, e.g., H3CCICl, PhSO2Br. They are named by placing the
name of the halide after the name of the acyl radical, e.g., acetyl chloride, benzenesulfonyl bromide.
acyloins: α-Hydroxy ketones RCH(OH)COR. An acyloin name is formed by changing the -ic acid
or -oic acid of the trivial name of the acid RCOOH to -oin. Thus, H3CCH(OH)COCH3 is
acetoin. They are now usually given normal substitutive names, e.g., 3-hydroxy-2-butanone.
aetio-: See etio.
aglycones (aglycons): Nonsugar compounds remaining after hydrolysis of the glycosyl groups
from glycosides.
aldazines: Azines of aldehydes.
aldehydo-: Occasionally used in place of a locant in order to denote unambiguously the position of
a functional derivative. For example, α-oxo-benzeneacetaldehyde aldehydo-hydrazone is
PhC(O)CHNHNH2.
aldimines: Imines derived from aldehydes, R1CHNR2.
aldoximes: Oximes derived from aldehydes, RCHNOH.
allenes: General term for substances containing CCC. The lowest member, propadiene
(H2CCCH2), is known as allene.
allo- (Greek “other”): A configurational prefix used in carbohydrate nomenclature. See carbohydrates. Also as a general prefix to denote close relationship, e.g., alloaromadendrene or the
more stable of a pair of geometric isomers, e.g., allomaleic acid (obsol.) = fumaric acid.
-amic acid: Denotes that one COOH group of a trivially named dicarboxylic acid has been replaced
by a CONH2 group. Thus, succinamic acid is H2NCOCH2CH2COOH.
amidines: Compounds of the type RC(NH)NH2. The ending -amidine can replace the -ic acid or
-oic acid of the name of the acid RCOOH. Thus, acetamidine is H3CC(NH)NH2.
amidoximes (amide oximes): Oximes of carboxamides or amides derived from hydroximic
acids, i.e., RC(NH 2)NOH or RC(NH)NHOH.

Acronyms and Miscellaneous Terms Used in Describing Organic Molecules

129

amidrazones (amide hydrazones): Hydrazones of carboxamides or hydrazides of hydroximic
acids, i.e., RC(NH2)NNH2 or RC(NH)NHNH2.
aminals: gem-Diamines, i.e., R2C(NR2)2 (R is the same or different).
-amoyl: Denotes a radical derived by loss of a hydroxy group from an amic acid. Thus, succinamoyl is H2NCOCH2CH2CO–.
amphi- (Greek “around”): For example, amphi-naphthoquinone (obsol.) = 2,6-naphthoquinone.
ang-: Prefix for angular, i.e., referring to an angular isomer (obsol.).
anhydrides: Compounds derived by the elimination of the elements of water from two acid molecules. Thus, acetic anhydride is (H3CCO)2O and acetic benzoic anhydride is H3CCOOCOPh.
Cyclic anhydrides, e.g., succinic anhydride are formed by the elimination of the elements
of water from a dibasic acid.
anhydro: A subtractive prefix denoting the loss of the elements of water within one molecule.
COOH

COOH

CH2OH
D-gulonic acid

CH2OH
2,3-anhydro-D-gulonic acid

anhydrosulfide: An analogue of an anhydride in which the oxygen atom connecting the two acyl
residues has been replaced by a sulfur atom. Anhydroselenides are the Se analogues.
-anilic acid: Denotes that one COOH group of a trivially named dicarboxylic acid has been
replaced by a CONHPh group. Thus, succinanilic acid is PhNHCOCH2CH2COOH.
anilides: N-Phenyl amides RCONHPh. They may be named by replacing the -ic acid or -oic acid
in the name of the acid RCCOH by -anilide. Thus, acetanilide is H3CCONHPh. Primed
locants are used for the phenyl ring.
anils: Another term for azomethine compounds or Schiff bases. Sometimes restricted to
N-phenylimines PhNCR2.
annulenes: Monocyclic conjugated hydrocarbons with the general formula (CH)n. Thus
[8]annulene is cyclooctatetraene.
ansa compounds (Latin “handle”): Compounds containing a ring system bridged by an aliphatic
chain. The simplest type consists of a benzene ring with the para positions bridged by a
methylene chain ten to twelve atoms long.
anthocyanins: Flavonoid pigments of glycosidic nature. On hydrolysis they give anthocyanidins,
which are oxygenated derivatives of flavylium salts.
anthra: The ring fusion prefix derived from anthracene.
apo (Greek “from”): In general means “derived from,” e.g., apomorphine. Oxidative degradation
products of carotenoids can be named as apocarotenoids. The prefix apo- preceded by a
locant is used to indicate that all of the molecule beyond the carbon atom corresponding to
that locant has been replaced by a hydrogen atom. The prefix diapo- indicates removal of
fragments from both ends of the molecule.
ar-: Abbreviation for “aromatic,” used as a locant to indicate an attachment at an unspecified position on an aromatic ring. Thus, in ar-methylaniline the methyl group is attached to the
aromatic ring and not to the amine N atom.
Ar: Denotes an unspecified aryl group.
arenes: A general name for monocyclic and polycyclic aromatic hydrocarbons.
arynes: Hydrocarbons derived formally from arenes by removal of a hydrogen atom from two-ring
carbons, e.g., benzyne.

130

Organic Chemist's Desk Reference, Second Edition

as-: Abbreviation for asymmetric, as in as-triazine (1,2,4-triazine). Sometimes used to indicate
1,2,4-substitution on an aryl ring, e.g., as-trichlorobenzene is 1,2,4-Cl3C6H3.
-azane: With a numerical prefix, -azane denotes a chain of nitrogen atoms. Thus, triazane is
H2NNHNH2, tetrazane is H2NNHNHNH2, etc.
-azene: With a numerical prefix, -azene denotes a chain of nitrogen atoms containing one double
bond. Thus, triazene is N2NNNH, tetrazene is H2NNNNH2, etc.
azi: –NN–. Usually used when both free valencies are attached to the same atom.
azines: Compounds containing the azino group. They may be named by adding the word azine after
the name of the corresponding aldehyde or ketone. Thus, acetone azine is (H3C)2CN–
NC(CH3)2. Azines is sometimes used as a general term to refer to six-membered heterocycles containing nitrogen in the ring.
azoles: Azoles is sometimes used as a general term to refer to five-membered heterocycles containing nitrogen in the ring.
azomethines: Compounds with the formula R2CNR′. When the N atom is substituted (R′ ≠ H),
they are known as Schiff bases. Azomethine itself is methanimine, H2CNH.
azonic acids: Compounds with structure R2N(O)OH.
benzeno: –(C6H4)–. Bridge name used in naming bridged fused ring systems.
benzo: The ring fusion prefix from benzene. See Chapter 4.
betaine: Trivial name for zwitterionic compounds characterised by Me3N+CH2COO–. Also used as a
class name for similar compounds containing a cationic centre and an anionic centre; they are
also called inner salts and zwitterionic compounds. Named as hydroxide, inner salts in CAS.
biimino: –NH–NH–. Used in naming bridged fused ring systems.
bisnor: See nor.
Bunte salts: Salts of S-alkyl thiosulfates with structure RSS(O)2O –M+.
calixarenes: Cyclic oligomers formed from para-substituted phenols and formaldehyde.
R
CH2
OH

calixarenes

See Shinkai, S., Tetrahedron, 49, 8933, 1993. Gutsche, C. D., Calixarenes: An Introduction
(Monographs in Supramolecular Chemistry) (Cambridge: Royal Society of Chemistry, 2008).
carba: Occasionally used as a replacement prefix indicating that a carbon atom has replaced a
heteroatom.
carbamates: Salt or esters of carbamic acid H2NCOOH or of N-substituted carbamic acids
R2NCOOH.
carbenes: Used as a general name for a type of neutral species in which the carbon atom is covalently bonded to two groups and also bears two nonbonding electrons, i.e., derivatives of
methylene, :CH2.
carbinol: Old name for the parent H3OCH in naming substituted alcohols. Thus, diphenylcarbinol
is Ph2CHOH and triethylcarbinol is (H3CCH2)3COH
-carbolactone: Suffix denoting the presence of a lactone ring fused to a ring system.
O
O
1,10-phenanthrenecarbolactone

-carbonitrile: Suffix denoting –C≡N.

Acronyms and Miscellaneous Terms Used in Describing Organic Molecules

131

carbonium compounds: Electron-deficient, positively charged, tricoordinate carbon atoms. For
example, H3C+ is methylium, C6H5+ is phenylium.
carboranes: A contraction of carbaboranes. Compounds in which a boron atom in a polyboron
hydride is replaced by a carbon atom.
carboximide (dicarboximide): Suffix denoting an imide of a dicarboxylic acid. See also imides.
O
NH
O

1,2-Cyclohexanedicarboximide

carbylamines: Isocyanides.
carbynes: Neutral species, R–C, in which the carbon atom is covalently bonded to one group and
also bears three nonbonding electrons.
carceplex: A complex formed by a carcerand. See Cram, D. J., et al. JACS, 116, 111, 1994. Chapman,
R. G., et al., JACS, 116, 369, 1994.
carcerand: A globular molecule capable of encapsulating smaller molecules in its interior cavity.
catecholamines: Derivatives of 4-(2-aminoethyl)-1,2-benzenediol.
catenanes: Compounds having two or more rings connected in the manner of the links of a chain,
without a covalent bond between the rings.
cavitand: A compound containing a geometrically enforced cavity large enough to accommodate
simple molecules or ions. See Cram, D. J., et al., Container Molecules and Their Guests
(Cambridge: Royal Society of Chemistry, 1997).
ceramides: N-Acylated sphingoids. See sphingoids.
chalcones (chalkones): Substituted derivatives of the parent compound 1,3-diphenyl-2-propen-1-one,
PhCHCHCOPh.
chelates: Compounds in which a multidentate ligand is bound to a receptor centre, i.e., the central
atom of a coordination complex.
clathrates: Inclusion compounds in which the guest molecule is in a cage formed by the host molecule or by a lattice of host molecules.
corrinoids: Compounds containing the corrin nucleus.
2

19
18
17

NH
16

9
10

N
15

11
12
13

The number 20 is omitted when numbering the corrin nucleus so that the numbering system will correspond to that of the porphyrin nucleus.

See Pure Appl. Chem., 48, 495, 1976.
crown ethers: A class of macrocyclic ethers that form chelates with cations.
O

O
O

18-crown-6

The name 18-crown-6 indicates a total of eighteen ring atoms including six oxygens.

132

Organic Chemist's Desk Reference, Second Edition

cumulenes: Compounds having three or more cumulative double bonds; R2CCCCR2.
cyanates: Compounds containing the –OCN group. Thus, methyl cyanate is MeOCN.
cyanides: Compounds containing the –CN group. Thus, ethyl cyanide is EtCN. The more usual
name is nitriles. Note that EtCN is propanenitrile.
cyanohydrins: Cyanoalcohols. Acetone cyanohydrin is (H3C)2C(OH)(CN); ethylene cyanohydrin
is HOCH2CH2CN.
cyclitols: Cycloalkanes in which the hydroxyl group is attached to each ring atom. See Chapter 5.
cyclo: Denotes the formation of a ring by means of a direct link between two atoms with loss of
one hydrogen from each, e.g., cyclohexane, cyclotrisilane. In terpene and steroid names
cyclo- indicates that an additional ring has been formed by means of a direct link between
atoms of the fundamental skeleton.

H
2
3

1
4

3,5-cyclopregnane

cyclodextrins: Cyclic oligosaccharides consisting of α-d-(1→4)-linked d-glucose residues.
cyclophanes: Cyclic compounds having two or more aromatic rings with aliphatic bridging chains.

2,2-[1,4]cyclophane

de: The prefix de- followed by the name of a group or atom denotes replacement of that group or
atom by hydrogen. Thus, in de-N-methylmorphine, the N–Me group of morphine has been
replaced by N–H. Sometimes used in steroid nomenclature to denote the loss of an entire
ring as in de-A-cholestane. Des- is more frequently used instead.
dehydro: Loss of two hydrogen atoms from a compound designated by a trivial name can be denoted
by the prefix didehydro. Thus, 7,8-didehydrocholesterol is cholesterol with an additional
double bond between atoms 7 and 8. In common usage, dehydro is sometimes used instead
of didehydro. Dehydro can also mean removal of water, e.g., dehydromorphine.
dendrimer: Highly branched oligo- and polymeric compounds formed by reiterative reaction
sequences. Also called starburst dendrimers, cascade molecules, and arborols.

See Tomalia, D. A., et al., Angew. Chem. Int. Ed. Engl., 29, 138 (rev.), 1990.
depsides: Esters formed from two or more molecules of the same or different phenolic acids.
depsipeptides: Compounds containing amino acids and hydroxy acids (not necessarily α-hydroxy
acids) and having both esters and peptide bonds.
des-: Occasionally used in steroid/terpenoid nomenclature to describe loss of an entire ring, as
in des-A-cholestane.
diazoate: Metal diazoates are compounds with the formula RNN–OM (M = metal). Thus,
PhNNONa is sodium benzenediazoate.
-diazonium: Ions RN2+. Named by adding the suffix -diazonium to the name of the parent substance RH. Thus, PhN2+Cl– is benzenediazonium chloride.
didehydro: See dehydro.
dinor: See nor.
dioxy: –O–O–. Used when the free valencies are attached to different atoms that are not otherwise
connected. Also called epidioxy.

Acronyms and Miscellaneous Terms Used in Describing Organic Molecules

133

diterpenoids: Terpenes having a C20 skeleton.
dithio: –S–S–. Usually used when the free valencies are attached to different atoms that are not
otherwise connected.
dithioacetals: Sulfur analogues of acetals R2C(SR)2 (R is the same or different).
eicosanoids: See icosanoids.
enamines: Vinylic amines containing the unit N–CC–. Enamino is a general term for a radical
derived from an enamine by removal of a hydrogen from the nitrogen atom.
enols: Vinylic alcohols, tautomeric with aldehydes and ketones, containing the unit HO–C.
epi (Greek “upon”): In carbohydrate chemistry, denotes an isomer differing in configuration
at the α-carbon. Generally, to denote the opposite configuration at a chiral centre (e.g.,
4-epiabietic acid). Also denotes a 1,6-disubstituted naphthalene (obsol.).
epoxides: Cyclic ethers. Usually restricted to three-membered cyclic ethers (oxiranes).
etheno: –CHCH–. Used as a bridge in naming bridged fused ring systems.
ethers: Compounds R1OR2. The word ether is used in radicofunctional nomenclature. Thus, diethyl
ether is Et2O (sometimes called ethyl ether), methyl phenyl ether is MeOPh, and ethylene
glycol monomethyl ether is MeOCH2CH2OH.
ethiodide, ethobromide, ethochloride: Denotes a base quaternised with ethyl iodide, ethyl bromide, or ethyl chloride.
ethoxide: The anion EtO –. Thus, sodium ethoxide is EtONa.
etio (aetio) (Greek aitia, “cause”): Denotes a degradation product, e.g., etiocholanic acid.
fatty acids: Carboxylic acids derived from animal or vegetable fat or oil. The term is sometimes
used to denote all acyclic aliphatic carboxylic acids. See Chapter 5.
flavonoids: A large group of natural products that are widespread in higher plants, derived by
cyclisation of a chalcone precursor
friedo-: In a triterpene name, friedo- denotes that a methyl group has migrated from one position
to another.
27

H
25
2
3

1
4

10
5

12
11 26 13
9
14

H
6

8
7

D-friedo-

normal triterpene

H
25

D:A-friedo-

D:B-friedo27
25

H
H

D:C-friedo-

134

Organic Chemist's Desk Reference, Second Edition

fullerenes: Compounds composed of an even number of carbon atoms forming a cage-like
fused structure with twelve five-membered rings and the rest six-membered rings, e.g.,
[60]-fullerene.
fulminate: An ester of fulminic acid (HONC). Thus, methyl fulminate is MeONC.
functional group: A group characterised by the presence of heteroatoms or unsaturation, which
can take part in chemical reactions, e.g., –COOH, –SH.
furanoses: Cyclic acetal or hemiacetal forms of saccharides in which the ring is five-membered.
See Chapter 5.
furfural: As a radical name, furfural denotes 2-furanylmethylene. Furfural usually refers to
2-furancarboxaldehyde.
gem(inal): Used to denote that two groups are attached to the same atom, as in gem-diol and gemdimethyl groups.
glucosinolates: Mustard oil glycosides.
glycans: Polysaccharides made up of monosaccharide units linked glycosidically.
glycaric acids: Another name for aldaric acids.
glycerides: Esters of glycerol with fatty acids.
glycols: Olefinic sugars with a double bond between positions 1 and 2.
glycols: Diols. For example, ethylene glycol is HOCH2CH2OH and propylene glycol is H3CCH(OH)
CH2OH.
glycopeptides, glycoproteins: Substances in which a carbohydrate component is linked to a peptide or protein.

See J. Biol. Chem., 262, 13, 1987.
Grignard reagents: Organomagnesium halides RMgX having a C–Mg bond.
halohydrins: Halo alcohols. For example, ethylene bromohydrin is BrCH2CH2OH.
helicenes: Ortho-fused polycyclic aromatic compounds that have a helical structure.

hexahelicene

hemiacetal: A compound with formula R1CH(OH)OR2 or R1R2C(OH)OR3.
hemicarcerand: A bow-shaped molecule capable of complexing small molecules in its cavity. See
carcerand.
hemiketal: A hemiacetal derived from a ketone.
hemimercaptals, hemimercaptoles: Compounds R1R2C(SH)(SR3).
hetero (Greek heteros, “other”): Prefix meaning “different,” e.g., heteroxanthine, heterocycle.
homo: Denotes incorporation of CH2 as an additional member in a ring in a steroid or a terpene;
also, for example, in homophthalic acid.

H
2

3
4 4a

A-homoandrostane

hydrazide: A compound formed by the replacement of the hydroxy group of an acid by –NHNH2.
Thus, acetohydrazide is H2CCONHNH2 and benzenesulfonohydrazide is PhSO2NHNH2

Acronyms and Miscellaneous Terms Used in Describing Organic Molecules

135

hydrazidines: Compounds RC(NNH2)NHNH2. The term has also been applied to RC(NH)
NHNH2, RC(NH)NH2, and RC(NH2)NNC(NH2)R.
hydrazo: –NHNH–. Usually used when the free valencies are attached to different atoms that are
usually otherwise connected. Hydrazo compounds are compounds RNHNHR. For example, hydrazobenzene is PhNHNHPh.
hydrazone: A compound derived from an aldehyde or ketone by replacement of the carbonyl oxygen by NNH2. Thus, acetone hydrazone is (H3C)2NNH2.
hydrazonyl: Suffix denoting a radical formed by loss of OH from a hydrazonic acid.
hydro: Denotes an added hydrogen atom. Thus, dihydro denotes saturation of one double bond.
hydrodisulfides: Compounds R–S–SH.
hydrogen: The word hydrogen is used to indicate an acid salt or ester of a dibasic acid. Thus, potassium hydrogen heptanedioate is HOOC(CH2)5COOK.
hydroperoxides: Compounds R–O–OH. Thus, ethyl hydroperoxide is EtOOH.
hydrosulfides: Old name for thiols. Thus, ethyl hydrosulfide is EtSH.
hydroxamamides: Another name for amidoximes.
-hydroximoyl: Suffix denoting an acyl radical formed by removal of OH from a hydroximic acid.
hypo (Greek “under”): Indicates a lower state of oxidation, e.g., hypoxanthine.
hypochlorite: A salt or ester of hypochlorous acid (HOCl). Thus, methyl hypochlorite is MeOCl.
i-: Obsolete form of iso-, as in i-pentane.
icosanoids: Unsaturated C20 fatty acids and related compounds such as leukotrienes.
imides: A class of compounds derived by replacement of two OH groups of a dibasic acid by –NH–
or –N(R)–. See also carboximides.
O

O
OH

O
succinic acid

succinimide

imidogen: HN:, a neutral monovalent nitrogen species (see nitrenes).
imidoyl: Suffix denoting a radical formed by removal of OH from an imidic acid.
imines: Compounds R1R2CNH. They can be named by adding the suffix -imine either to a parent
name or to an -ylidene radical. Thus, H3C(CH2)4CHNH is 1-hexanimine or hexylideneimine.
inclusion compounds: Compounds in which one kind of molecule (the guest compound) is embedded in the matrix of another (the host compound).
indane: A hydrocarbon, C9H10. Should not be used for InH3, the CAS name for which is indium
hydride (InH3).
-inium: Denotes a positively charged species derived from a base with a name ending in -ine. Thus,
anilinium is PhNH3+.
inner salts: Chemical Abstracts considers compounds such as betaines to be formed by the loss
of water from the corresponding hydroxides and names them by use of the expression
“hydroxide, inner salt.”
I
COO

–

(2-carboxyphenyl)phenyliodonium,
hydroxide, inner salt

inosamines: Aminodeoxyinositols, i.e., 6-amino-1,2,3,4,5-cyclohexanepentols.

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inositols: 1,2,3,4,5,6-Cyclohexanehexols. See Section 5.2.
inososes: 2,3,4,5,6-Pentahydroxycyclohexanones.
iso: Prefix denoting isomerism, especially carbon chain branching (isohexanoic acid = 4-methylpentanoic acid). In the old literature it can be treated as a separable prefix, e.g., iso-propyl; in the
modern literature it is usually treated as an inseparable prefix, e.g., isopropyl.
isocyanates: Compounds RNCO. Thus, methyl isocyanate is MeNCO.
isocyanides: Compounds RNC. Thus, methyl isocyanide is MeNC.
isonitriles: See isocyanides.
isoprenoids: Compounds such as terpenes that are derived from isoprene units. Isoprene is
2-methyl-1,3-butadiene, H2CC(CH3)CHCH2.
isothiocyanates: Compounds RNCS. Thus, methyl isothiocyanate is MeNCS.
-ium: Suffix denoting a positively charged species.
ketals: Acetals derived from ketones.
ketazines: Azines derived from ketones.
ketene: A general term for compounds R1R2CCO. Ketene itself is ethenone, H2CCO.
keto: oxo O. Now used only in a generic sense, as in “ketoesters.”
ketones: Compounds R1COR2. Usually named by use of the suffix -one or the prefix oxo-.
Radicofunctional names are sometimes used. Thus, dimethyl ketone is H3CCOCH3 and
ethyl methyl ketone is H3CCH2COCH3.
ketoximes: Oximes of ketones.
lactams: Compounds containing a group of –CO–NH– as part of a ring. β-Lactams have fourmembered rings, γ-lactams have five-membered rings, δ-lactams have six-membered
rings, etc.
O

N
H

γ-butyrolactam or 4-butanelactam

lactides: Intramolecular cyclic esters formed by self-esterification from two or more molecules of
a hydroxy acid.
O
O

dilactide
(from lactic acid)

lactims: Tautomers of lactams containing a group –C(OH)N– as part of a ring.
lactones: Intramolecular cyclic esters of hydroxyacids. They contain a group –CO–O– as part
of a ring. β-Lactones have four-membered rings, γ-lactones have five-membered tings,
δ-lactones have six-membered rings, etc.
O
H
HO
HO
H

1C
2

OH
H

CH2OH

D-glucono-1,4-lactone

Acronyms and Miscellaneous Terms Used in Describing Organic Molecules

137

lambda (λ): Italicised prefix indicating abnormal (higher) valency of a ring heteroatom, e.g., S, Se,
Te. For such compounds, the 2006 CAS nomenclature changes introduce this system to
replace roman numeral valency suffixes used in 9CI.
S

N
N

1,2,3-Thia-(SIV)diazole, 9CI → 1λ 4δ2-thiadiazole

leuco- (Greek “white”): Prefix denoting usually the reduced colourless form of a dye.
lin-: Denoting a linear arrangement of rings (obsol.).
m-: Abbreviation of meta-.
macrolides: Macrocyclic lactones.
mercaptals: Dithioacetals.
mercaptans: An old name for thiols. Thus, ethyl mercaptan is ethanethiol, EtSH.
mercaptoles: Mercaptals derived from ketones.
meso-: The middle position of substitution, e.g., the 9-position in anthracene (obsol.; the normal
meaning of meso- is described in Chapter 7).
mesoionic compounds: Polyheteroatom five-membered ring betaines stabilised by electron
delocalisation, having dipole moments not less than 5D, and in which electrons and positive
charge are delocalised over a part of the ring and attached groups, and in which electrons
and a negative charge, formally on an α-atom (normally a heteroatom), are delocalised over
the remaining part of the ring. See munchnones and sydnones.

Cheung, K., et al., Acta Cryst. Sect. C, 49, 1092, 1993. Ollis, W. D., et al., Tetrahedron, 41,
2239, 1985.
mes(yl)ate: A salt or ester of methanesulfonic acid, MeSO3H.
meta-: Denotes 1,3-substitution on a benzene ring.
metacyclophanes: Cyclophanes in which the benzene rings are meta-substituted by the aliphatic
bridging chains.
methine: C–.
methiodide, methobromide, methochloride, methoperchlorate, methopicrate, etc.: Indicates a
base quaternised with methyl iodide, etc.
monoterpenoids: Terpenoids having a C10 skeleton.
morpholides: Anions formed from morpholine by loss of the hydrogen attached to the nitrogen.
munchnones: Mesoionic oxazolin-5-ones.
R1

R3
N

+
–
R2
O
munchnones

mustard oils: An old term for isothiocyanates.
mustards: (SCH2CHRX)2, X = halogen.
n-: Abbreviation for normal (unbranched), as in n-butane.
naphtho: The ring fusion prefix derived from naphthalene.
-naphthone: Suffix denoting a ketone with formula RCOC10H7 (C10H7 = 1- or 2- naphthyl).
neo (Greek “new”): (1) A newly characterised stereoisomer (e.g., neomenthol). (2) A quaternary
branched hydrocarbon. (3) In terpenes, the prefix neo- indicates the bond migration that
converts a gem-dimethyl grouping directly attached to a ring carbon into an isopropyl group.
neosteroids: Occasionally used to refer to ring B aromatic steroids.
nitrenes: Neutral derivatives of monovalent nitrogen, including the parent compound HN:
(nitrene or imidogen).

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nitrile oxides: Compounds RCN(O). Thus, benzonitrile oxide is PhCNO.
nitriles: Compounds RCN. The suffix -nitrile denotes a –CN group at the end of an aliphatic chain.
Thus, butanenitrile is H3CCH2CH2CN. Nitriles can also be named as cyano-substituted
compounds.
CN
O
2-furannitrile or 2-cyanofuran

nitrilimines: HC≡N+–N–H.
nitr(o)imines: RR′CNNO2.
nitrogen mustards: RN(CH2CHRX)2 X = halogen.
nitrones: N-Oxides of imines. Compounds containing the grouping CN(O)R.
nitronic acids: aci-Nitro compounds, R1R2CN(O)OH.
nitroxides: Free radicals derived from N-hydroxy amines by loss of the hydrogen from the oxygen
atom, i.e., R1R2N–O. Thus, dimethyl nitroxide is Me2N–O∙
nor-: Used mainly in naming steroids and terpenes, nor denotes elimination of one CH2 group
from a chain or contraction of a ring by one CH2 unit.

H
H

19-norpregnane

1
3 5

A-norandrostane

In older usage, particularly for monoterpenes, nor denotes loss of all methyl groups
attached to a ring system, e.g., norborane, norpinane. The plural form should be bisnor
when two carbon atoms are lost from the same site and dinor where they are lost from different sites, but in practice the terms are used interchangeably.
o-: Abbreviation of ortho-.
-oin: Suffix denoting an acyloin RCH(OH)COR.
-olate: Suffix denoting a salt of an alcohol. Thus, sodium methanolate is MeONa.
olefins: Old term for alkenes.
-olide: Suffix denoting a lactone.

O
O
5-pentanolide

O
O
4-pentanolide

O
O
3-pentanolide

oligo-: Prefix meaning “a few,” as in oligosaccharides, oligopeptides.
-olium: Denotes a positively charged species derived from a base with a name ending in -ole,
e.g., pyrrolium.
-onium: Indicates a positively charged species such as ammonium, phosphonium, sulfonium, oxonium, etc.
ortho-: Denotes 1,2-substitution in a benzene ring (abbreviated to o-).
ortho-: The highest-hydrated form of an acid, e.g., orthocarbonic acid, C(OH)4.
orthoesters: Compounds R1C(OR2)3, esters of the hypothetical ortho acids R1C(OH)3. Thus, ethyl
orthoacetate is H3CC(OEt)3; orthoacetic acid is H3CC(OH)3.
osazones: Dihydrazones having the two hydrazone groups attached to adjacent carbon atoms.
They are formed from compounds having the grouping –COCO– or –CH(OH)CO–, in the
latter case with formal oxidation of the hydroxy group.

Acronyms and Miscellaneous Terms Used in Describing Organic Molecules

139

oxides: (1) Ethers have sometimes been named as oxides. Compounds R1OOR2 are dioxides,
R1OOOR3 are trioxides, etc. Thus, dimethyl oxide is Me2O, dimethyl dioxide is MeOOMe,
dimethyl trioxide is MeOOOMe. (2) An alkene oxide is the epoxide derived from that
alkene. Thus, styrene oxide is phenyloxirane. (3) Denotes the salt of an alcohol. Thus,
sodium ethoxide is EtONa. (4) Indicates addition of O at a heteroatom, as in trimethylamine N-oxide (Me3NO), phosphine oxide (H3PO), and pyridine N-oxide.
oxido: Sometimes used to mean “epoxy.” Also used as a substituent prefix to denote O = attached
to a heteroatom, as in amine oxides; thus, 1-oxidopyridine is pyridine N-oxide.
oximes: Compounds RCHNOH and R1R2CNOH considered to derive from carbonyl compounds.
Thus, acetaldehyde oxime is H3CCHNOH and acetamide oxime is H3CC(NOH)NH2.
oxonium: H3O+.
ozonides: 1,2,4-Trioxolanes formed by reaction of ozone at a CC double bond.
p-: Abbreviation of para-.
paddlane: A tricyclo[m,n,o,p1, m+2]alkane, commonly called an [m,n,o,p]paddlane.
C
(CH2)m

(CH2)n

(CH2)o

(CH2)p

para- (Greek “beside,” “beyond”): Denotes 1,4-substitution in a benzene ring.
paracyclophanes: Cyclophanes in which the benzene rings are para-substituted by the aliphatic
bridging chains.
paraffins: Alkanes (obsol.).
per: (1) The highest state of oxidation, e.g., perchloric acid. (2) Presence of a peroxide (–O–O–) group,
e.g., perbenzoic acid. (3) Exhaustive substitution or addition, e.g., perhydronaphthalene.
perbromo, perchloro, perfluoro, etc.: Denotes that all hydrogen atoms (except those that are part
of functional groups, e.g., CHO, COOH) have been replaced by halogen atoms. Use can
cause ambiguity.
perhydro: Denotes full hydrogenation of a fused polycyclic system.
peri: The 1,8-substitution pattern in napthalene (obsol.). Also, fusion of a ring to two or more
adjoining rings, e.g., perinaphthindene.
peroxides: Compounds R1O–OR2. Thus, ethyl phenyl peroxide is EtOOPh and dibenzoyl peroxide
is PhCO–O–O–COPh.
peroxy acids: Acids containing the group –C(O)OOH. Thus, peroxypropanoic acid is H3CCH2C(O)
OOH (also named as propaneperoxoic acid).
phenanthrylene: Phenanthrenediyl.
phenetidides: N-(Ethoxyphenyl) amides. They may be named analogously to anilides. Thus,
aceto-p-phenetidide is N-(4-ethoxyphenyl)acetamide, H3CCONHC6H4OEt-4 (obsol.).
pheniodide, phenobromide, phenochloride: Indicates a base that has been (formally) quaternised
with phenyl iodide, phenyl bromide, or phenyl chloride (reaction not usually feasible in
practice).
-phenone: Suffix denoting a ketone with formula RCOPh.
O

O
5' 6' 1'
4' 3' 2'

acetophenone

benzophenone

phenoxide: The anion PhO –. Thus, potassium phenoxide is PhOK.

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phosphatidic acids: Derivatives of glycerol in which one primary OH group is esterified with
phosphoric acid and the other two OH groups are esterified with fatty acids.
phosphazines: Compounds containing the group CN–NP≡, e.g., (H3C)2CN–NPPh3.
phosphine: PH3. Phosphine imine is H3PNH, phosphine oxide is H3PO, phosphine sulfide is
H3PS. Diphosphine is H2P–PH2, triphosphine is H2PPHPH2.
phosphite: Denotes a salt or ester of phosphorous acid.
phosphonium: H4P+–.
phosphorane: PH5.
phosphoric acid: (HO)3PO. Diphosphoric acid is (HO)2P(O)–OP–(O)(OH)2, triphosphoric acid is
(HO)2P(O)–O–P(O)(OH)–OP–(O)(OH)2.
phthalocyanines: Compounds based on the polycyclic phthalocyanine ring system (IUPAC), as
shown.

1 2

30
31

29
32

6N
7
12

picrate: An ester, salt, or addition compound of picric acid (2,4,6-trinitrophenol).
pinacols: A general term for tetrasubstituted 1,2-ethanediols. Pinacol itself is 2,3-dimethyl-2,3butanediol (H3C)2C(OH)C(OH)(CH3)2.
poly: Many.
polypyrroles: See Chapter 5.
porphyrins: See Chapter 5.
propellane: A tricyclo[m,n,o,01,m+2]alkane, called an [m,n,o]propellane. A special case of paddlanes
with one zero bridge.
C
(CH2)n

(CH2)m

(CH2)o

proteins: Polypeptides of high molecular weight (above 10,000).
pseudo (Greek “false”): Prefix indicating resemblance to, especially isomerism with, e.g., pseudocumene or ψ-cumene.
pyro: Prefix designating compounds formed by heating, usually with the elimination of a simple
molecule, e.g., water or CO2.
pyrophosphoric acid: Diphosphoric acid, (HO)2P(O)–O–P(O)(OH)2.
pyrophosphorous acid: Diphosphorous acid, (HO)2P–O–P(OH)2.
pyrromethenes: Compounds containing two pyrrole rings joined by a –CH group.
quercitols: Deoxyinositols, i.e., 1,2,3,4,5-cyclohexanepentols.
quinines: Diketones derived from aromatic compounds by conversion of two CH groups into CO
groups.
quinone imines (quinonimines): Compounds derived from quinones by replacement of one or
more of the quinone oxygens by HN.
quinone methides (quinomethides): Compounds derived from quinones by replacement of one or
more of the quinone oxygens by H2C.

Acronyms and Miscellaneous Terms Used in Describing Organic Molecules

141

O
O
9,10-phenanthrenequinone
or phenanthraquinone

O
p-benzoquinone

retro- 1. (in carotene names): The prefix retro- and a pair of locants denote a shift, by one position,
of all single and double bonds delineated by the pair of locants. The first locant cited is
that of the carbon atom that has lost a proton, and the second that of the carbon atom that
has gained a proton.
2. (in peptide names): When used with a trivially named peptide, retro- denotes that the
amino acid sequence is the reverse of that in the naturally occurring compound.
rotaxanes: A class of molecules in which an annular component is free to rotate around a spine,
but is prevented from escape by end groups on the spine. A prefix indicates the number of
molecular components.

See Stoddart, J. F., et al., J. Am. Chem. Soc., 114, 193, 1992.
N

OSi(CH(CH3)2)3

O
O
((H3C)2CH)3SiO

O
N

N
[2]rotaxane

s-: Abbreviation for symmetric(al), as in s-triazine (1,3,5-triazine). Also an abbreviation for sec-,
as in s-butyl. Both of these usages are obsolete; the current use of s- is as a descriptor for
pseudoasymmetric centres (see Chapter 7).
S-: Denotes sulfur as a locant. Also an important stereochemical descriptor; see Chapter 7.
Schardinger dextrins: Another name for cyclodextrins.
Schiff(s) bases: See azomethines.
sec-: Abbreviation of secondary, as in sec-butyl.
seco: In steroid and terpene names, seco denotes fission of a ring with addition of a hydrogen atom
at each terminal group thus created.
13

H 14

H
H
podocarpane

13
14

H
H
13,14-secopodocarpane

selenane: Hantzsch-Widman systematic name for selenacyclohexane. Not a name for SeH2, one
name for which is selane.
selenenimine: H2SeNH.
selenides: Compounds R1SeR2, selenium analogues of ethers and sulfides. Compounds R1SeSeR2
are diselenides, R1SeSeSeR2 are triselenides, etc.
seleno: Denotes replacement of oxygen by selenium as in selenourea, (H2N)2CSe. Also denotes
the bridging radical –Se–. Usually used when the free valencies are attached to different
atoms that are not otherwise connected.

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selenocyanates: Compounds RSeCN. Thus, methyl selenocyanate is MeSeCN.
-selenol: Suffix denoting –SeH. Selenols are selenium analogues of alcohols and thiols.
selenones: Compounds R1Se(O)2R2, selenium analogues of sulfones. Thus, dimethyl selenone is
Me2Se(O)2.
selenoxides: Compounds R1Se(O)R2, selenium analogues of sulfoxides. Thus, dimethyl selenoxide
is Me2Se(O).
selones: Compounds R1C(Se)R2. Selenium analogues of ketones and thiones. Thus, 2-butaneselone is H3CC(Se)CH2CH3.
semicarbazones: Compounds R1R2CNNHCONH2. For example, acetone semicarbazone is
(H3C)2CNNHCONH2.
semioxamazones: Compounds R1R2CNNHCOCONH2.
sesquiterpenoids: Terpenoids having a C15 skeleton.
sester: Numerical prefix meaning 2.5, as in sesterterpenes.
sesterterpenoids: Terpenes having a C25 skeleton.
silane: SiH4. Disilane is H3SiSiH3, trisilane is H3SiSiH2SiH3.
sil(a)thianes: Compounds of general formula H3Si–[SSiH2]–nSSiH3, named disilathiane (n = 0),
trisilathiane (n = 1), etc.
silazanes: Compounds of general formula H3Si–[NHSiH2]n–NHSiH3, named disilazane (n = 0),
trisilazane (n = 1), etc.
silicones: Polymeric or oligomeric siloxanes.
siloxanes: Compounds of general formula H3Si–[OSiH2]n–OSiH3, named disiloxane (n = 0), trisiloxane (n = 1), etc.
sphingoids (sphingolipids): Refers to sphingamine (d-erythro-2-amino-1,3-octadecanediol), its
homologues, stereoisomers, and derivatives. Important biochemicals.
starburst dendrimer: See dendrimer.
styphnate: An ester, salt, or addition compound of styphnic acid (2,4,6-trinitro-1,3-benzenediol).
sulfanes: Compounds containing an unbranched chain of sulfur atoms may be named disulfanes,
trisulfanes, etc. Thus, phenyl trisulfane is Ph–S–S–SH.
sulfenes: S,S-dioxides of thioaldehydes and thioketones.
sulfides: Compounds R1SR2. Sulfur analogues of ethers. Thus, diethyl sulfide is Et2S. R1S– SR2 are
disulfides, R1S– S– SR2 are trisulfides, etc. The word sulfide is also used to denote addition
of S to a heteroatom, as in phosphine sulfide (H3PS).
sulfines: S-Oxides of thiocarbonyl compounds, such as PhCOSO.
sulfones: Compounds R1S(O)2R2. Thus, dimethyl sulfone is Me2SO2.
sulfonylides: Cyclic intermolecular esters of hydroxysulfonic acids. Analogues of lactides.
sulfoxides: Compounds R1S(O)R2. Thus, dimethyl sulfoxide is Me2SO (sometimes called methyl
sulfoxide). Sulfoxides having two different alkyl groups are chiral (tetrahedral S atom).
sulph-: British variant spelling of sulf-. IUPAC now recommends sulf-.
sultams: Cyclic esters of sulfonic acids. They contain the grouping –S(O)2N(R)– as part of a ring.
sultims: Tautomeric forms of sultams. They contain –S(O)(OH)N– as part of a ring.
sultines: Cyclic esters of hydroxysulfinic acids. They contain –S(O)O– as part of a ring.
sultones: Cyclic esters of hydroxysulfonic acids. Analogues of lactones. They contain the grouping
–S(O)2O– as part of a ring.
sydnones: A class of compounds derived from 1,2,3-oxadiazolidin-5-one, substituted in
the 3-position, by loss of two hydrogen atoms, resulting in a mesoionic system
(see mesoionic compounds). Sydnone imines are similar compounds derived from
1,2,3-oxadiazolidin-5-imine.

Acronyms and Miscellaneous Terms Used in Describing Organic Molecules

+
–

NH
N

sydnone

+
–

143

NH
N

sydnone imine

sym-: Abbreviation for symmetric(al), as in sym-dichloroethane, ClCH2CH2Cl. Sometimes used to indicate 1,3,5-substitution in a benzene ring; e.g., sym-trichlorobenzene is 1,3,5-trichlorobenzene.
t-: Abbreviation for tertiary, as in tert-butyl. Also trans; see Chapter 7.
tannins: Plant polyphenols.
tellurane: Hantzsch-Widman systematic name for telluracyclohexane. Not a name for TeH2, one
name for which is tellane.
tellurides: Compounds R1TeR2, tellurium analogues of ethers.
tellurilimine: H2TeNH.
telluro: –Te–. Used when the free valencies are attached to different atoms that are not otherwise
connected.
tellurones: R1C(Te)R2, tellurium analogues of ketones.
terpenoids: A class of organic compounds, the common structural feature of which is a carbon
skeleton of repeating isoprene units.
tert-: Abbreviation of tertiary as in tert-butyl.
thetins: Inner sulfonium salt analogues to betaines, e.g., Me2S+CH2COO –.
-thial: Suffix denoting –CHS at the end of an aliphatic chain. Thus, hexanethial is H3C(CH2)4CHS.
thio: Denotes replacement of oxygen by sulfur as in thiophenol, thiourea. Also, the multiplying
radical –S–. Dithio is –S–S–, trithio is –S–S–S–, etc.
thioacetals: Sulfur analogues of acetals.
thioaldehydes: Sulfur analogues of aldehydes, RCHS.
thiocarboxylic acids: Compounds RC(S)OH, RC(O)SH, and RC(S)SH, sulfur analogues of carboxylic acids.
thiocyanates: Compounds RSCN. Thus, methyl thiocyanate is MeSCN.
thioketones: Sulfur analogues of ketones.
-thiol: Suffix denoting –SH. Thiols are compounds RSH.
thiolates: Metal derivatives of thiols. Thus, sodium ethanethiolate is EtSNa.
-thione: Suffix denoting a thioketone. Thus, 2-butanethione is H3CC(S)CH2CH3.
thiophenol: Benzenethiol, PhSH. In order to avoid confusion, hydroxythiophene is called
thiophene-ol.
thi(o)uronium salts: Quaternary derivatives of thiourea (isothiourea) with structure [RSC(NH)
NH2]+ X–.
-thioyl: Suffix denoting an acyl radical derived from a thioic acid.
toluidides: N-(Methylphenyl) amides. They may be named analogously to anilides. Thus, aceto-mtoluidide is H3CCONHC6H4CH3 -3.
tosylate (tosate): An ester of p-toluenesulfonic acid.
tricyclo: For an explanation of names like tricyclo[5.1.0.03,5]octane, see Chapter 4 (Von Baeyer
names).
triterpenoids: Terpenoids having a C30 skeleton.
tropones: Compounds containing the cyclohexa-2,4,6-trienone ring system.
ulosaric acids, ulosonic acids, ulosuronic acids: Acids derived from the oxidation of ketoses (see
Section 5.1.3).
-ulose: Denotes a ketose; -ulofuranose and -uropyranose denote a ketose in the cyclic hemiacetal
form having five- and six-membered rings, respectively (see Section 5.1.5).
unsym-: Abbreviation for unsymmetrical, as in unsym-dichloroethane, H3CCHCl2. Sometimes
used to indicate 1,2,4-substitution on a benzene ring; e.g., unsym-trichlorobenzene is
1,2,4-trichlorobenzene.

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Organic Chemist's Desk Reference, Second Edition

urethanes: Esters of carbamic acid. Urethane itself is ethyl carbamate, and hence phenylurethane
is PhNHCOOEt.
uronic acids: Monocarboxylic acids derived by oxidation of the terminal CH2OH of aldoses. Names
are formed by replacing the -ose ending of the aldose name with -uronic acid (see Section
5.1.3).
uronium salts: Quaternary derivatives of urea (isourea) with structure [ROC(NH2)NH2]+ X–.
v-: Abbreviation for vicinal, as in v-triazine (1,2,3-triazine).
vic-: Abbreviation for vicinal. Sometimes used to indicate 1,2,3-substitution on a benzene ring;
e.g., vic-trichlorobenzene is 1,2,3-trichlorobenzene.
vicinal: Neighbouring.
Wittig reagents: Phosphonium ylids R3P+—C–R2↔ R3PCR2.
xanthic acids: O-Esters of carbonodithioic acid, ROC(S)SH. Thus, ethylxanthic acid is EtOC(S)
SH. Xanthates are salts of xanthic acids.
xylidides: N-(Dimethylphenyl)amides. They may be named analogously to anilides. Thus, aceto2,4-xylidide is CH3CONHC6H3(CH3)2-2,4.
-ylene: Suffix denoting a bivalent radical in which the free valencies are on different atoms.
-ylidene: Suffix denoting a bivalent radical in which the free valencies are on the same atom.
ylides: Compounds in which an anionic site is attached directly to a heteroatom carrying a positive charge; e.g., triphenylphosphonium methylide is Ph3P+–CH–. Discontinued as an index
term in the CAS 2006 changes. Compounds formerly indexed with a suffix -ylide are now
indexed using the term inner salt.
-ylidyne: Suffix denoting a trivalent radical in which the free valencies are on the same atom.
ylium: Suffix denoting a carbonium atom; e.g., methylium is H3C+, acetylium is H3CC+(O).
zwitterionic compounds: General term for compounds containing both positive and negative
charges. See also betaine.

7 Stereochemistry
John Buckingham

Further reading:
Eliel, E. L., and Wilen, S. H., Stereochemistry of Organic Compounds (Wiley Interscience, 1994).
Basic Terminology of Stereochemistry, IUPAC Recommendations 1996, www.chem.qmul.
ac.uk/iupac/stereo. Pure Appl. Chem. 68, 2193, 1996.
Naming and Indexing of Chemical Substances for Chemical Abstracts, 2007 editon, p. 71 et. seq.
(American Chemical Society, Columbus, Ohio)
Stereochemistry deals with the topography and transformations of the molecule in three dimensions,
i.e., the features that go beyond the connectivity (which atoms are joined to which). It is conventional
to distinguish between configuration (features that cannot be interconverted without bond breaking)
and conformation (different states of the same molecule that can interconvert without bond breaking), but this distinction is not precise. There are some types of molecules (those with bond character
intermediate between single and double, biaryls with medium-sized ortho-substituents, etc.) where
the energy barrier to interconversion from one isomer to another is comparable to their energy content
at room temperature. At sufficiently low temperatures, all conformations become configurations.
A chiral (handed) molecule is one capable of existence in a pair of nonsuperposable mirrorimage forms. Nearly all configurations now found in the literature are absolute configurations,
i.e., the handedness or chirality of the molecule in real space is known. This was not possible until
the 1950s, so the old literature must be consulted with care. By coincidence, the arbitrary configurations assigned before the 1950s to compounds related to the standard molecules glucose and serine,
and defined using the old d,l- system, were correct. (On the other hand, some terpenoid configurations that had been arbitrarily related to camphor had to be reversed.)
Chirality of a molecule (or any other object) can be more formally defined by reference to group
theory. Chiral molecules belong to the lowest point groups Cn and Dn. An example of a molecule
belonging to the lowest possible point group C1 is Cabde. An example of a chiral molecule belonging to a higher point group is trishomocubane (D3 symmetry). Another way of stating the symmetry
requirements is that a chiral molecule cannot have a centre, plane, or alternating axis (rotationreflection axis) of symmetry, although it may have one or more rotation axes.

D3-Trishomocubane

The term chiral is also used to describe a sample of a substance. When used in this sense, it is
not necessary that every molecule in the sample has the same handedness; see the definitions below
for optical purity, enantiopurity, etc. A racemic sample is one containing (statistically) equal numbers of right-handed and left-handed enantiomers, and therefore showing zero optical activity at all
wavelengths. A sample can also be chiral, nonracemic; i.e., it contains an excess of one enantiomer.
Chirality is most frequently studied by chiroptical methods. This term covers (1) measurement of optical rotation at a single wavelength, (2) measurement of optical rotation as a function
145

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of wavelength (optical rotatory dispersion (ORD); ORD values may be positive or negative), and
(3) measurement of circular dichroism (CD) as a function of wavelength (values always positive).
Definitions of terms used in these techniques are given below. A nonracemic chiral sample may
have zero optical rotation at a given wavelength if that is the wavelength at which its ORD curve
crosses the origin. A chiral sample always shows ORD/CD maxima, although they may be too weak
to measure.
The following is a summary of the representation and description of basic stereochemistry. See
also the relevant entries in Chapter 5, especially under amino acids and carbohydrates.

7.1 The Sequence Rule: R and S
Leading references are:
Cahn, R. S., J. Chem. Educ., 41, 116, 1964.
Cahn, R. S., et al., Angew. Chem., Int. Ed. Engl., 5, 385, 1966.
Prelog, V., et al., Angew. Chem., Int. Ed. Engl., 21, 567, 1982.
The sequence rule (also known as the Cahn-Ingold-Prelog (CIP) system) is the universal system of
describing absolute configurations. It provides a method of arranging atoms or groups in an order
of precedence and is used to assign stereochemical descriptors, R-, S-, also E-, Z-, and others.
The molecule is viewed from opposite the group of lowest (fourth) priority. If the remaining
groups in decreasing order of priority are arranged in a clockwise manner, then the configuration is
R. If they are arranged in an anticlockwise manner, then the configuration is S.
In the following diagrams the order of priority of the groups is a > b > c > d. Hence, the molecule
is viewed from opposite group d.
a

d
b

line of
sight

d
c

a
d

(R)-

a
c

line of
sight

d
b

(S)-

The rules as they apply to compounds with centres of chirality may be summarised as follows:

1. Atoms of higher atomic number take precedence over those of lower atomic number. Thus,
Cl > S > O > N > C > H. Lone pairs are assigned the lowest possible priority.
2.Isotopes of higher atomic weight take precedence over those of lower atomic weight. Thus,
3H > 2H > 1H.
3.When the first atoms in each group are the same, then the priorities are determined by the
atomic numbers of the atoms that are directly attached to these. Thus, CH2Cl > CH2OH >
CH3 because Cl > O > H and (H3C)3C > (H3C)2CH > H3CCH2 because C > H. If no difference is observed for this second set of atoms (second sphere), then the third sphere and so
on are considered in turn until there is a difference.
When carrying out this process of outward exploration, the following principles must
be adhered to: (1) all ligands in a given sphere must be explored before proceeding to the
next sphere, and (2) once a precedence of one path over another has been established in
one sphere, that precedence is carried over to the next sphere.

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Stereochemistry

4.In groups containing a double or triple bond, for the purposes of determining priority, the
multiple bond is split into two or three bonds, as follows:
H

H
becomes

and takes
precedence
over

(O) (C)

becomes

and takes
precedence
over

(N) (N) (C) (C)

H
becomes

H
(C)
H

H (C)

H
C

CH2NH2

and takes
precedence
over cyclohexyl

Only the multiply bonded atoms themselves are duplicated and not the atoms of groups
attached to them.
5.When the difference between substituents is in configuration, then in general Z > E and
R > S. However, the formal definition is that an olefinic ligand in which the substituent of
higher sequence priority is on the same side of the alkene double bond as the chiral centre
takes priority. This definition does not correspond with either E,Z- or cis/trans- (change to
the rules in 1982), The subscript n (for “new”) is used in cases of doubt.
3

CH3

Application of the 1982 rule to assignment of configuration.
The order of priority is 1 > 2 > 3 > 4 because although 2 has Z-configuration and 1 has
E-, residue 1 has the higher priority group (Cl) cis to the chiral centre. The compound
has Rn-configuration (adapted from Eliel and Wilen).

6.In addition, a further rule was introduced in 1982 that says like precedes unlike, and this
takes precedence over the rule that R- precedes S-.
COOH
HO
OH
OH
OH
OH
COOH

Application of the like precedes unlike rule.
The configurational label at C-3 is S.
Programs are available for assigning CIP labels algorithmically, e.g., one is included in recent versions of Chemdraw.

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7.1.1 List of Common Groups in CIP Priority Order
I > Br > Cl > PR2 > SO3H > SO2R > SOR > SR > SH > F > OTs > OAc> OPh > OMe > OH
> NO2 > NMe3+ > NEt2 > NMe3 > NHCOPh > NHR > NH2 > COOR > COOH > COPh >
COCH3 > CHO > CH2OR > CH2OH > CN > CH2NH2 > Ph > C≡CH > But > cyclohexyl
> CH(CH3)CH2CH3 > CHCH2 > CH(CH3)2 > CH2Ph > CH2CHCH2 > CH2CH(CH3)2 >
CH2CH3 > CH3 > D > H
R*- and S*- are relative stereochemical descriptors. Thus, (R*, R*) indicates two centres of like
chirality (either both R- or both S-) and (R*, S*) indicates two centres of unlike chirality. (RS) and
(SR) are used to denote racemates (see RS-).

7.2 Graphical and Textual Representations of Stereochemistry
7.2.1 Compounds with One Chiral Centre
Where the absolute configuration is known, structures can be represented either as Fischer type diagrams or as perspective diagrams. Fischer diagrams follow the convention that the principal chain
occupies the vertical position, with the head of the chain uppermost.

7.2.2 Compounds with Two Chiral Centres
In addition to Fischer and perspective diagrams, physical organic chemists use Newman and sawhorse diagrams to show conformations as well as configurations of two-centre compounds.
Figure7.1 shows 3-bromo-2-chlorobutanoic acid in Fischer-type, zigzag (closely related to flying
wedge), sawhorse, and Newman representations.
COOH
H

CH3
(a)

CH3

COOH
Cl
(b)

COOH

H
(c)

CH3

COOH
Br

H
(d)

Figure 7.1 (2S,3R)-3-Bromo-2-chlorobutanoic acid showing some possible representations: (a) Fischer-type
diagrams. (b) Zigzag. (c) Sawhorse diagram showing one of three staggered conformations. (d) Corresponding
Newman projection.

In CAS presentation (9CI period), the labels R*,S* are used not only where the absolute configuration is unknown, but also where it is known. R* is allocated to the centre of highest sequence
priority, e.g., in the above example, position 3 (since Br > Cl). The general descriptor (R*,S*) for this
diastereoisomer is then modified where the absolute configuration is known, and the citation refers
to the optically active material. Thus. the isomer illustrated above is [R-(R*,S*)], and its racemate,
when specifically referred to, is [(R*,S*)-(±)].
These CAS rules, which had been in use since the beginning of the 9th Collective Index period
(1972), have now been thoroughly revised to give a simplified and more intuitive description. The
need for a single expression to describe the total stereochemistry of a molecule has been eliminated.
Stereochemical terms are now placed within the parts of a chemical name to which the stereochemical information applies. The following diagram shows the now superseded 9CI descriptors
alongside the revised equivalents, which are closer to now current CAS practice.
The symbols (2RS,3RS) and (2RS,3SR) can also be used for the racemic diastereoisomers of
compounds with two chiral centres though CAS does not use this system. Where the absolute configuration appears to be unknown, asterisked symbols, e.g. (2R*, 3R*) may be used.

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Stereochemistry
COOH
Cl
H

COOH

CH3
(2R,3R)
[R-(R*,R*)][9CI]

CH3
(2S,3S)
[S-(R*,R*)][9CI]

CH3
(2S,3R)
[R-(R*,S*)][9CI]

(2RS,3RS)
[(R*,R*)-(±)]-(9CI)
(±)-threo

CH3
(2R,3S)
[S-(R*,S*)][9CI]

(2RS,3SR)
[(R*,S*)-(±)]-(9CI)
(±)-erythro

Graphical representation of stereoisomers of
3-bromo-2-chlorobutanoic acid

CAS now registers and names substances with partially defined stereochemistry. Previously,
partial stereochemistry was generally ignored. The presence of unknown chiral centers is indicated
by the addition of the term [partial]- to the end of the normal stereochemical descriptor. When the
reference ring or chain has incompletely defined chiral atoms/bonds, the format cites the stereochemistry using R and S terms with their nomenclature locants for all known centers. If this method
is used to describe a substance for which only relative stereochemistry is known, rel is added to the
stereochemical descriptor. Any stereochemical descriptor marked as rel always cites the first centre
as R-.
Beilstein uses a number of additional stereochemical descriptors for specialised situations.
Examples are (RS), Ra, Sa, and Ξ. For full details, see the booklet Stereochemical Conventions in
the Beilstein Handbook of Organic Chemistry, issued by the Beilstein Institute, and Section 7.6.

7.2.3 Cyclic Structures
The application of the above principles to simple cyclic structures is straightforward. The E,Z notation should not be used to define configurations of cyclic compounds such as 1,2-cyclobutanediol.
(R,S)- descriptors can be assigned to prochiral centres in more symmetrical molecules by a
simple extension of the sequence rule. For example, in 1,3-cyclobutanediol the OH group at each
centre has priority 1 and the H atom priority 4.
(1) (4)

(1) (4)

HO H
(3)

HO H
(2)

H OH
(4) (1)

(2)

(3)

HO H

(1) (4)

An arbitrary choice is made between methylene groups (2) and (3), giving (1RS,4RS) chirality to
the trans form and (1RS,4SR) to the cis form. The result is independent of the arbitrary choice made.
An alternative and more rigorous treatment considers C-1 and C-3 as centres of pseudoasymmetry and assigns them the appropriate symbols r and s (actually rn and sn; see definitions below). (Note
that according to this treatment, the cis-isomer is 1sn,3sn and the trans-isomer 1rn,3rn; i.e., changing the configuration at one centre changes both descriptors.) For a full explanation, see Eliel and
Wilen, p. 667.
In the case of cyclic structures with several substituents (e.g., cyclitols), the (α,β)-convention may
be clearer and unambiguous. See also cyclitols in Chapter 5.

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7.3 Chiral Molecules with No Centres of Chirality
Extensions of the CIP rules deal with molecules that are chiral as a whole but contain no chiral
centres.

7.3.1 Allenes, Biaryls, and Related Compounds
A molecule such as abCCCde is chiral if a ≠ b and c ≠ d (axial chirality). The additional rule is
that near groups precede far groups.
2

H
1

H
C

H3C

CH3

Application of the axial chirality rule to an allene: Near end of axis precedes far; chirality is aR.
Care is needed in some cases; e.g., an allene with four different substituents could alternatively
be assigned a label using central chirality. To avoid doubt, use the descriptor (R)axial or aR.

7.3.2 Molecules with Chiral Planes
The application of CIP rules to compounds showing planar chirality is complex because of ambiguities in choosing the correct plane.
The (M,P) system has also been used, which treats the molecule as a helix (minus and plus
helicity), but is strictly redundant because M always ≡ R and P always ≡ S. For most purposes, it is
better to avoid having to specify chirality whenever possible. A picture is worth a thousand words.
To make it clear that planar chirality is assigned, the symbols PR/ PS (or Rplanar/Splanar) can be used.

COOH
P or pR[2.2]Paracyclophane4-carboxylic acid

7.4 E and Z
These are stereochemical descriptors used to describe the configuration about a double bond. E- is
usually but not necessarily equivalent to trans-, and Z- to cis-. Priority of atoms or groups is decided
in the same way as for R and S and if those of highest priority on the double bond are trans to each
other, then the compound has E configuration, if cis, then it has Z.
Br

(Z)-2-Bromo-2-butene
equivalent to trans(priorities Br > CH3 > H)

For many compounds with more than one double bond, CAS cites E- and Z- without locants. The
E- and Z- descriptors are cited in descending order of seniority. The most senior double bond is that

151

Stereochemistry

which has the highest-ranking (sequence rule) substituent attached. Thus, the stereochemistry of the
compounds below is described as (E,Z)- because the phenyl group is the highest-ranked substituent
attached to a doubly bonded atom.
See Blackwood, J. E., et al., J. Chem. Doc., 8, 32, 1968.
Ph

E-

ZCOOH
(E,Z)-

7.5 The D,L-System
d- and l- are older configurational descriptors used to denote the configuration of chiral molecules,
especially carbohydrates and α-amino acids. Fischer projections are used to assign the symbols
d- and l-.
Nowadays, R,S- descriptors are used for all classes of molecule except for the following:
• Carbohydrates. Here the application of the sequence rules to the many –CH(OH)– groups
is possible but tedious and confusing. Carbohydrates retain the system based on assigning
the key chiral centre to the d- or l- series, as described in Chapter 5.
(+)-Glyceraldehyde is defined as d-; the OH group attached to C(2) is on the right-hand
side of the Fischer projection in which the CHO group appears at the top. Its enantiomer is
defined as l- because the OH group is on the left-hand side. (The d- and l- symbols were
originally assigned arbitrarily; in the 1950s it was found that (+)-glyceraldehyde has the
absolute configuration represented here.)
CHO
H

CHO

CH2OH

D-glyceraldehyde

CHO
HO

CHO

CH2OH

L-glyceraldehyde

For carbohydrates, in general, the position of the OH group attached to the highestnumbered carbon atom in the chain determines the assignment of d- and l-. For instance,
in d-glucose the OH at position 5 is on the right-hand side of the Fischer projection.
1

CHO
H
HO

2
3
4

H
H

CHO

CH2OH

D-glucose

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• Amino acids. These retain the d,l- system because all of the protein amino acids belong
to the l- series, but not all of them are S- according to the sequence rule. See Chapter 5.
Biochemists often use the d,l- system for synthetic compounds derived from amino acids
where most organic chemists would use R,S-. In α-amino acids, the l-compounds are
those in which the NH2 group is on the left-hand side of the Fischer projection in which the
COOH group is at the top. Conversely, the d-compounds are those in which the NH2 group
is on the right-hand side.
COOH

COOH

H 2N

CH3

CH3
L-alanine

COOH
H

NH2
CH3

NH2

CH3
D-alanine

d- and l- do not relate to the sign of rotation of an optically active sample, which is designated (+)- or (–)- (formerly d- and l-).
The abbreviations dG /lG and dS /lS were formerly used in cases where there was potential ambiguity
in assigning d/l configurations and refer to configurations relative to glucose and serine, respectively.
The d,l- system should no longer be used except for compounds that are closely and unambiguously related to either carbohydrates or amino acids. This is to avoid ambiguity. By suitably modifying the groups on, e.g., an amino acid in different ways, it is possible to arrive at compounds
that can be described either as d- or l-, depending on the route used, whereas the R,S- system is
unambiguous.
The symbol for a racemate is d,l- or (±)-.

7.6 Descriptors and Terms Used in Stereochemistry
(For designations of Greek letters, see after Z.)
a: Molar amplitude of an ORD curve, a = ([Φ]1 + [Φ]2)/100, where [Φ]1 and [Φ]2 are the molar rotations at the first and second extrema.
achiral: Not chiral, i.e., superposable on its mirror image.
achirotopic: See chirotopic.
allo-, altro-, arabino-: Carbohydrate-derived prefixes. See Chapter 5.
ambo-: Used after a locant to indicate a preparation containing approximately equal amounts of
diastereomers at the indicated centre, e.g., (2ambo, 4′R,8′R)-β-tocopherol (Beilstein; not in
widespread use):
anancomeric: Fixed in a single conformation by geometric constraints or by the overwhelming
preponderance of one possible conformation.
anti-: (1) (Greek “opposite”) Stereochemical descriptor used for bridged bicyclic compounds. In a
bicyclo[X.Y.Z] compound (X ≥ Y > Z), anti- denotes that a substituent on the Z bridge points
away from the X bridge.
anti

syn
exo
endo
X

153

Stereochemistry

(2) Conformation of a molecule, e.g., butane, having opposite groups (distinct from eclipsed
and gauche)
H
H

CH3

CH3(H)

CH3

H
H
gauche

H(H)

H(CH3)

CH3

CH3(CH3)

H
H

(H)H

CH3
anti

eclipsed

H(H)
eclipsed

Conformations of butane

(3) Equivalent to trans- or E- when used to indicate the stereochemistry of oximes and
similar CN compounds (obsol.: use E or Z).

(4) Relative configuration of two stereogenic centres in a chain. Denotes that when drawn
as a zigzag, the ligands are on opposite sides of the plane. Opposite of syn-.
anticlinal, antiperiplanar, synclinal: An anticlinal conformation in a molecule X-A-B-Y is when
the torsion angle about the AB bond is +90° to 150° or –90° to –50° in an antiperiplanar
conformation it is +150° to –150°; in a synclinal conformation it is +30° to +90° or –30°
to –90°.
antimer, antipode, optical antipode: Obsolete terms for enantiomer.
asymmetric: Lacking all elements of symmetry (point group C1). Not the same as dissymmetric, q.v.
atropisomer: An isolable stereoisomer resulting from a sufficiently high rotation barrier about a
single bond. Difficult to define rigorously; a working definition is that the barrier to rotation should exceed 22.3 kcal mol–1, which gives a t1/2 for inversion of approximately 1,000 s
at 300K.
axial: (1) An axial bond is one perpendicular to the plane containing or almost containing the
majority of atoms in a cyclic molecule, e.g., cyclohexanes.
a

a
e

e
e
a

a
e

b
e

a
a

Position of bonds and substituents in the chair and boat conformations of cyclohexane:
a = axial, e = equatorial, b = bowsprit, and f = flagpole.

(2) Axial chirality arises from the disposition of groups about an axis, e.g., in an allene;
see above.
bowsprit/flagpole bonds: Bonds at the out-of-plane carbon atoms of the boat conformation of,
e.g., cyclohexanes. See diagram under axial.
c-: Abbreviation for cis- (obsol.). Extensively used, with elaboration, in Beilstein.
CD: Circular dichroism.
cF, tF, catF: Prefixes used in Beilstein to indicate cis- and trans- in a Fischer diagram (cat refers to
the end of a chain, cat = catenoid). Not used elsewhere.
chiral carbon atom: A carbon atom in a molecule that is a centre of chirality. Better called a chiral
centre, or even better, a centre of chirality, since this makes it clear that it is a portion of
the molecule that is designated as chiral, not the carbon atom itself.
chirotopic: Any point in a molecule that is located in a chiral environment, not necessarily within
a chiral molecule. See Eliel and Wilen, p. 53.
cis-: Stereochemical descriptor denoting that two groups are on the same side of a ring or other
plane. Also used to indicate the configuration of a double bond; Z- and E- are now used
instead. E- does not always correspond to trans-, nor Z- to cis-. See above under E/Z.
cisoid: Obsolete term for s-cis (see below).

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conformer (conformational isomer): A stable conformation of a molecule that is located at an
energy minimum; e.g., ethane has three conformers.
cryptochiral: Substance that is chiral but with undetectable chiroptical properties, e.g.,
(H3C)3CCHDOH.
d-: Abbreviation for dextro- (obsol.).
d-: A configurational descriptor. Fuller description given above. dS and dG referred to configurations relative to serine and glucose, respectively (obsol.).
dr-,ds-,lr-,ls-: Elaborations of the d,l- notation found only in Beilstein (obsol.).
de: Diastereomeric excess. Analogous to enantiomeric excess, q.v.
dextro-: Denotes a compound that, in solution, rotates the plane of plane-polarised light to the
right, as seen by the observer (obsol.). Equivalent to (+)-.
diastereo(iso)mers: Stereoisomers that are not enantiomers.
diastereotopic: Faces of a double bond that are not symmetry related. Addition of a new ligand
gives different diastereomers.
dissymmetric: Old term for chiral. Distinction from asymmetric; asymmetry (e.g., molecules
Cabde) applies only to objects of point group Cn whereas dissymmetry applies also to
objects of higher point groups Dn.
dl-: Denotes a racemic mixture (d- + l-) (obsol.; avoid; use (±)-).
d,l-: Denotes a racemic mixture (d- + l-) (avoid except for carbohydrates or amino acids; use (±)or RS-).
e-: Equivalent to E- to denote configuration at a single bond with restricted rotation (Beilstein;
obsol.).
E-: Stereochemical descriptor for alkenes, cumulenes with an odd number of double bonds, and
alkene analogues such as oximes. It means that the two substituents with highest CIP priority at the two ends of the bond are trans- to each other (German entgegen).
eclipsed: See anti-.
ee: Enantiomeric excess. The percentage excess of the enantiomer over the racemate. A pure enantiomer has 100% ee, a racemate 0%. ee = [R –S]/[R + S] × 100%.
enantiomorph: Obsolete term for enantiomer. Applied in the correct sense to define any mirrorimage object.
endo-: Stereochemical descriptor used for bridged bicyclic systems. In a bicyclo[X.Y.Z] compound
(X ≥ Y > Z), exo- denotes that a substituent on an X or Y bridge is on the opposite side of the
molecule from the Z bridge. For a diagram, see anti-.
ent-: The prefix ent- (a contracted form of enantio-) denotes configurational inversion of all the
asymmetric centres whose configurations are implied in a name. It is used to designate a
trivially named peptide in which the configurations of all the amino acid residues are the
opposite of those in the naturally occurring compound.

H
H
abietane

H
H
ent-abietane

Caution: Addition of, e.g., a 3R-OH group to ent-abietane produces ent-3S-abietanol.

equatorial: A bond lying in or close to the plane containing most of the atoms in a cyclic molecule,
e.g., cyclohexane. See diagram under axial.
erythro-: A configurational prefix. See carbohydrates. It is used generally to denote compounds
with two chiral centres having the erythrose-like configuration (ambiguity can arise).

155

Stereochemistry

exo- (Greek “outside”): Stereochemical descriptor used for bridged bicyclic systems. In a
bicyclo[X.Y.Z] compound (X ≥ Y > Z), exo- denotes that a substituent on an X or Y bridge is
on the same side of the molecule as the Z bridge. For the diagram, see anti-.
fiducial group: The group that determines the assignment of a stereochemical label (conformational or configurational).
flagpole bond: See bowsprit and diagram under axial.
galacto-, gluco-, glycero-, gulo-: Carbohydrate-derived prefixes. See Chapter 5.
gauche: See anti-.
homochiral/heterochiral: Refers to a set of two or more molecules or fragments having the same
or opposite chiralities, e.g., l-alanine/l-alanine vs. l-alanine/d-alanine.
homofacial/heterofacial: On the same or opposite side of a defined plane or face.
homotopic/heterotopic: Two or more ligands that are identical when viewed in isolation are heterotopic if replacement of each in turn by a new ligand gives a nonidentical product.
i-: Abbreviation for inactive, as in i-tartaric acid. (obsol.).
ido-: Carbohydrate-derived prefix. See Chapter 5 under carbohydrates.
l-: (1) An abbreviated form of levo- or laevo (obsol.). (2) Stereodescriptor for diastereomers with
stereocentres both R- or both S- (= “like” as opposed to u = “unlike”). Not widely used.
l-: A configurational descriptor. See d-. For lS and lG, see d-.
l(a)evo: Indicates a molecule that, in solution, rotates the plane of plane-polarised light to the left.
Equivalent to (–)-.
lyxo-, manno-: Carbohydrate-derived prefixes. See Chapter 5.
(M-), (P-): Stereochemical descriptors (M = minus, P = plus) introduced to describe the chirality
of helical molecules. Extension of the CIP system to planar chirality gave an alternative
description aR/aS for helical molecules such as helicenes, aR invariably ≡ (M) and aS ≡
(P), but for compounds showing planar chirality the reverse, with pR ≡ (P) and pS ≡ (M).
Best avoided. See Section 7.3.2.
[M] or [Φ]: Molecular rotation, defined as [α] × MW/100. Specific rotation corrected for differences in MW. The symbol [M] and the term molecular rotation are now deemed incorrect,
and the term molar rotation denoted by [Φ] is preferred.
meso-: Denotes an internally compensated diastereoisomer of a chiral compound having an even
number of chiral centres, e.g., meso-tartaric acid. Formally defined as an achiral member
of a set of diastereomers that also contains chiral members.
mutarotation: Phenomenon shown by some substances, especially sugars, in which the optical
activity changes with time. A correct presentation is, e.g., [α]D20 + 20.3 → –101.2 (2h)(c,
1.2 in H2O).
op: Optical purity, defined as a percentage, op = 100[α]/[α]max, where [α]max = rotation of the pure
enantiomer (identical solvent, temperature, and concentration). Enantiomer excess (ee) is
now preferred in careful studies because op is a physical property that may sometimes vary
nonlinearly with enantiomeric composition (Horeau effect), and ee is now often measured
by nonoptical methods.
ORD: Optical rotatory dispersion.
(P)-: See (M)-.
pro-R, pro-S: These terms are used to distinguish an identical pair of atoms or groups in a prochiral compound. That which leads to an R- compound when considered to be preferred
to the other by the sequence rule (without changing the priority with respect to the other
substituents) is termed pro-R; the other is termed pro-S.
CHO
pro-R H

pro-S

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pseudoasymmetric centre, pseudoasymmetry: Term used to describe centres such as C-3 in ribitol and xylitol (see Chapter 5). C-3 is not a chiral centre and not chirotopic since it lies
on a symmetry plane. It is, however, stereogenic because exchange of two of the attached
ligands leads to the other meso- form. (The other two stereoisomers of the pentitols represent a pair of enantiomers, d- and l-arabinitol.)
pseudochiral centre, pseudochirality: Alternative terms for pseudoasymmetric centre/pseudoasymmetry. Not recommended.
quasienantiomers, quasiracemate: Terms used in place of enantiomer, racemate, where the
components are similar but not identical. For example, (R)-2-bromobutanoic acid is quasienantiomeric with (S)-2-iodobutanoic acid and may form a quasiracemate with it.
R-: Stereodescriptor for chiral cenres or other stereogenic features in the CIP system. See above.
Subscripts may be used to denote chirality as a heteroatom, e.g., RS = chirality at a sulfur
atom.
r-: Stereodescriptor applied to centres of pseudoasymmetry. In ribitol (see Chapter 5), C-3 has
s-configuration, by application of the rule that an R-centre (C-4) has priority over an
S-centre (C-2). In xylitol, C-3 has r-configuration.
Ra or Raxial/Sa or Saxial: Stereodescriptors for R- or S-configuration at an axis of chirality.
rac-: Prefix for racemic. Alternative to (RS) or (±)-. Used (especially with natural product names)
to denote a racemate. In a peptide name rac- denotes that all the amino acids are dl. The
abbreviation racem- is found in Beilstein.
Re/Si: Descriptors for heterotopic faces in a prochiral molecule. See Eliel and Wilen, p. 484 for
a description.
rel-: Prefix indicating that a configuration is relative, not absolute. Use of the R*,S* notation
is preferred.
residual stereoisomer: The subset of the total set of stereoisomers of a compound that can be distinguished under specified conditions by a given technique. Thus, the axial and equatorial
stereoisomers of chlorocyclohexane are distinguishable by NMR at room temperature or by
laboratory manipulation at –160º, but not by laboratory manipulation at room temperature.
ribo-: Carbohydrate-derived prefix. See Chapter 5.
rn /sn (n = new): Applied to pseudoasymmetry descriptors resulting from a treatment deriving from
the 1982 paper, not present in earlier CIP documentation.
Rp or Rplanar/Sp or Splanar: Stereodescriptors for R- or S-configuration at a chirality plane. See
Section 7.3.2.
(RS)- and (SR)-: In a one-centre compound (RS) means the racemate, equivalent to (±). In a compound with two or more centres of chirality, RS and SR are used to define the relative
configurations of the centres in racemic diastereomers, e.g., (±)-threitol = (2RS,3RS)1,2,3,4-butanetetrol, erythritol = (2RS,3SR)-1,2,3,4-butanetetrol. Priority is given to (RS)for the lowest-numbered centre. (CAS uses R* and S* together with the (±)- identifier to
show that a racemate is meant.)
S-: Stereodescriptor for chiral cenres or other stereogenic features in the CIP system. See above.
s-: Stereodescriptor applied to centres of pseudoasymmetry; see r-.
Sa, Sp: See Ra , and Rp.
s-cis, seqcis, s-trans, seqtrans-: Obsolete forms of Z- and E-. However, s-cis and s-trans are also
used to define conformations about a single bond between two double bonds, with s-cis =
synperiplanar and s-trans = antiperiplanar.
Si: See Re.
staggered: Conformation of a molecule abcX-Ydef in which the torsion angle is 60º.
stereogenic centre: A carbon atom or other feature in a molecule that is a focus of stereoisomerism. Interchange of two ligands at a stereogenic carbon leads to inversion of configuration.

Stereochemistry

157

Chiral atoms are stereogenic, but not all stereogenic centres are chiral atoms. For example,
in an alkene abCCab the double bond is a stereogenic element.
syn-: (1) Stereochemical descriptor used for bridged bicyclic systems. In a bicyclo [X.Y.Z] compound (X ≥ Y > Z), syn- denotes that a substituent on the Z bridge points toward the X
bridge. For a diagram, see anti-. (2) Also used for configuration of oximes, etc. (obsol.; use
E/Z). (3) Conformational descriptor, see anti-.
synclinal: See anticlinal.
synperiplanar: A synperiplanar conformation in a molecule X-A-B-Y is when the torsion angle
about the AB bond is +30 to +90° or –30 to –90°.
t-: Abbreviation for trans- (obsol.). Extensively used, with elaboration, in Beilstein.
talo-: Carbohydrate-derived prefix. See Chapter 5.
tF: See cF.
threo-: A configurational prefix. See Chapter 4 under carbohydrates. Can be used generally to
denote stereoisomers of compounds having two chiral centres having the threose-like configuration. Ambiguity can occur.
trans-: Stereochemical descriptor denoting that two atoms or groups are on the opposite side of a
ring. Also used to indicate the configuration about a double bond. See cis-.
u- (unlike): See l-.
xylo-: Carbohydrate-derived prefix. See Chapter 4 under carbohydrates.
Z-: Opposite of E- for alkenes, etc. (German zusammen).
z-: Equivalent to Z in denoting configuration at a single bond exhibiting restricted rotation
(Beilstein; obsol.).
α-: (1) α without brackets refers to an experimentally measured rotation value, e.g., α = –19.2°
(obsol.). α in square brackets refers to the specific rotation of a compound in a given
solvent and at the experimental temperature, e.g., [α]D25 –57.4 (c, 0.25 in CHCl3); it is a
dimensionless number and a degree sign should not be used. The solvent and concentration should be stated as shown. Concentrations are given in g/100 ml.

(2) Indicates below-the-plane stereochemistry in steroids, terpenoids, etc., e.g., 5α-pregnane,
and below-the-plane configuration of substituents. In such stereoparents, the α- or
β-configuration at certain stereocentres may be implicit in the name of the stereoparent,
while others may need to be defined. In the name 3α-chloro-5α,10α-pregnane, the three
alphas perform different functions; 3α is the orientation of a substituent, 5α is inserted
because the stereoparent pregnane has an undefined 5-configuration and it has to be specified, and 10α reverses the normal pregnane 10β-configuration.

(3) α,β- indicates the configuration of the glycosidic bond in glycosides (see Chapter 5
under carbohydrates).

(4) α,β- was formerly used to denote side chain configurations in steroids (Fieser convention). Obsolete; use R- and S-.
αF, βF: Used in Beilstein to denote side chain configurations in steroids (Fischer representation).
Obsolete; use R- and S-.
β-: (1) Indicates above-the-plane stereochemistry in steroids, terpenoids, etc., e.g., 5β-pregnane.
(2) Indicates configuration of the glycosidic bond in glycosides. See also α-.
Δε: In circular dichroism, amplitude of the CD maximum; difference in molar absorption coefficients for right and left circularly polarised light. May be positive or negative.
θ: (1) Molar ellipticity in CD measurement, [θ] = [ψ] × MW/100. For small ellipticities, [θ] = 3298.2
× Δε.
(2) Symbol for bond angle.
ξ or Ξ: Lowercase xi (ξ) denotes unknown configuration at a chiral centre (alternative to α,β or
R,S), e.g., 1β,2β,3ξ-trihydroxy-12-ursen-23-oic acid. In Beilstein, Ξ is used in place of d or l

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where the configuration is uncertain or undefined. In the Combined Chemical Dictionary
(Section 1.2.1), the descriptor (ξ)- is also used for stereoisomers where it is uncertain which
enantiomer is described, e.g., natural products isolated only by GC and characterised spectroscopically or by MS where no determination of the enantiocomposition was made.
[Φ]: See [M].
ψ: Specific ellipticity in CD measurement.
ω: Abbreviation for torsion angle in a conformation.

Representation
8 Graphical
of Organic Compounds
The effective communication of chemical structure is essential for all chemists. Over the years
many different types of structure representation have been developed. Before the use of computers,
chemists drew structures manually, often using a linear text notation. As more sophisticated methods for drawing have become available, the trend has been toward two-dimensional stick structures,
such as the zigzag Natta projection (Figure8.1).
H3CH2C
H3CH2C

OH
OH

CH2CH2CH3

Figure 8.1 Linear text notation vs. Natta zigzag for 3-ethyl-3-hexanol.

There are no formal rules for the representation of chemical compounds, although a few special cases such as steroids and carbohydrates have evolved a preferred style. This chapter will
outline the revised drawing conventions used in the Combined Chemical Dictionary (CCD) (see
Section 1.2.1), which other chemists may wish to follow. (CCD diagrams have, however, been
added continuously over a period of nearly thirty years. This description is of best current practice.) These rules, when followed, will result in a drawing style that is consistent and unambiguous
to the reader.
The conventions adopted for CCD closely follow the International Union of Pure and Applied
Chemistry (IUPAC) recommendations on graphical representation standards for chemical structure
diagrams (Pure Appl. Chem., 80, 227–410, 2008) and graphical representation of stereochemical
configurations (Pure Appl. Chem., 78, 1897–1970, 2006). Both of these publications are recommended reading for all chemists and can be downloaded via the IUPAC website.

8.1 Zigzag Natta Projection
For the majority of chemical structures, the Natta projection provides a clear and unambiguous
representation of a compound. Generally speaking, all carbon and hydrogen atoms are implicit,
with the exception of those that form part of a functional group such as a carboxylic acid (COOH)
or aldehyde (CHO). The linear skeleton is drawn in the horizontal plane with numbering beginning
from the right-hand side.
Br
5

COOH

2-Bromo-4-methylpentanoic acid

In this representation the angle between bonds is 120°. Most chemical drawing packages have
a chain drawing tool that will automatically draw the correct angle. For compounds containing
carbon centres with four attached groups, the tetrahedral geometry is shown with the two nonhorizontal bonds separated by 60°.
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OH
COOH

HOOC
60°

8.1.1 Aromatic Compounds
For simple aromatic compounds the ring is orientated such that the 1 position is at the top or top
right of the ring and numbered in a clockwise direction, again keeping the general horizontal layout.
OH
6
5

1
4

2
3

NH2

5 6 1
4 3 2

COOH
Br

8.1.2 Heterocyclic Compounds
In CCD, heterocyclic compounds are drawn with the heteroatom toward the bottom or bottom right
and numbered counterclockwise. Many other information sources show the heteroatom at the top.
5 4 3
6 1 2

6 5
7
8

NH2

4 3
2
1 N

NH2

8.2 Stereochemistry
Stereochemical configuration is shown with the use of solid wedge and hashed lines. There are
some general rules used in CCD to avoid ambiguity:
• Wedge and dashed bonds are used as sparingly as possible to avoid confusion. The majority
of tetrahedral centres require only one such bond to imply the stereochemistry of the centre.
• Bonds between adjacent stereocentres: Stereobonds between two stereocentres can be misinterpreted since it is not always clear to which chiral centre they refer. In such cases the
stereobonds are drawn from the chiral atom to a nonchiral atom.
O

H
H

correct

incorrect

• Re-entrant bonds: Similar ambiguity in stereochemical interpretation occurs when a stereobond is drawn inside the obtuse angle between two other bonds as opposed to the reflex
angle.
H

H
correct

incorrect

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Graphical Representation of Organic Compounds

Examples often occur in large ring systems, but it is often possible to redraw the ring to avoid a
reentrant bond.
O
O
correct

incorrect

Using stereobonds to imply perspective: One exception to the rule above occurs when the stereocentre is part of a bridged ring system. In this case the reentrant bonds are drawn using stereobonds
since they are naturally pointing out of the plane of the paper, and the alternative results in ambiguous stereochemistry.

correct

incorrect

To avoid confusion, stereobonds should be drawn from the stereocentre when implying perspective whenever possible.

OH
OH

correct

OH
OH

incorrect

Numbers, InChI,
9 CAS
and Other Identifiers
See Gasteiger, J., and Engel, T., Chemoinformatics (Weinheim, Wiley/VCH, 2003) and Leach,
A. R., and Gillet, V. J., An Introduction to Chemoinformatics (Dordrecht, Springer, 2007); other
books are also available.

9.1 CAS Registry Numbers
9.1.1 Introduction
Chemical Abstracts Service (CAS) developed the CAS Registry System in the early 1960s to provide a means for determining whether a chemical substance reported in the scientific literature had
been indexed previously in Chemical Abstracts, and for retrieving the previously assigned index if it
had been. Each unique chemical structure recorded in the system is assigned a permanent identifying number, the CAS registry number.
The registry number in itself has no chemical significance, but is simply a serial number assigned
as a substance is entered into the registry system for the first time. The number has the format
NNNNNNN-NN-R, where R is a check digit calculated by computer program from the other nine
digits; by this means, errors in the transcription of registry numbers can be detected. Leading zeros
are suppressed, so the first group of digits may contain fewer than seven digits.
The check digit for the registry number N8N7N6N5N4N3-N2 N1-R is derived from the formula
below, where Q is an integer, which is discarded.

8 N 8 + 7 N 7 + 6 N 6 + 5 N 5 + 4 N 4 + 3 N 3 + 2 N 2 + N1
R
=Q+
10
10

9.1.2 Specificity
A substance is registered to the degree of structural detail given. This means that isomers, including
stereoisomers, each receive their own registry number. Examples are shown below.
25167-67-3
106-98-9
107-01-7
624-64-6
590-18-1
50-21-5
598-82-3
10326-41-7
79-33-7

Butene (isomer not specified
1-Butene
2-Butene (stereoisomer not specified)
(E)-2-Butene
(Z)-2-Butene
Lactic acid (stereochemistry unspecified)
(t)-Lactic acid (racemic mixture)
(S)-Lactic acid
(R)-Lactic acid

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Hydrates and salts receive their own registry numbers.
302-01-2
7803-57-8
14011-37-1
1184-66-3

Hydrazine
Hydrazine monohydrate
Hydrazine hydrochloride
Hydrazine sulfate

Labelled compounds receive their own registry numbers.
64-19-7
1112-02-3
1563-79-2

Acetic acid (unlabelled)
Acetic-d3 acid (D3CCOOH)
Acetic-l-13C acid (H3C13COOH)

9.1.3 Duplicate Registry Numbers
• CAS sometimes finds it necessary to register substances without full knowledge of their
structures. Examples are trivially named natural products and trade name materials. This
may lead to unintentional duplication in the registry system since the actual material may
be indexed at another CA index name based on information from another literature source.
Similar problems may arise when more than one structure is reported for the same chemical substance. When it is recognised that duplication has occurred and that a substance
has been assigned two registry numbers, one of the numbers is retained as the preferred
number, to which the other one is cross-referred.
• Certain substances are registered for non-CAS use, for example, substances registered
under the provision of the U.S. Toxic Substances Control Act (TSCA), substances for the
U.S. Adopted Names (USAN) Council of the U.S. Pharmacopeial Convention, and substances for the European Inventory of Existing Chemical Substances (EINECS).
• Others arise from the use of the registry system to support the preparation of index nomenclature. Thus, all parent ring systems are registered even when the parent compound has not
been made. Also, all components of addition compounds, mixtures, or copolymers are registered and, occasionally, one of these components may not have been reported in the literature.
In addition to these unintended duplications, which should eventually be reconciled by CAS,
there are many quasi-duplicates resulting from the liberal allocation of numbers.

9.1.4 Registry Numbers with Asterisks
CAS, in registering substances for the preparation of CA indexes, assigns registry numbers only
to substances that are described as unique chemical entities. However, through its activities in the
preparation of the TSCA and EINECS inventories, CAS has assigned registry numbers to substances that are not treated as unique chemical entities in its regular CA index processing. Registry
numbers assigned to substances of this type are identified by the presence of an asterisk following
the number. Examples are:
Tallow (61789-97-7*)
Terphenyl, chlorinated (61788-33-8*)
These registry numbers are not found in CA Volume Indexes.

9.1.5 Racemates
Prior to the 14th Collective Index, registry numbers were assigned to the (+/–)-forms (racemic mixtures) of compounds with one chiral centre. From the 14th Collective Index onward these assignments

165

CAS Numbers, InChI, and Other Identifiers

have been dropped in favour of using the stereochemistry unspecified number. In cases where the
(+/–)-number was earlier than the unspecified number, it replaces it as the unspecified number. Thus,
dl-malic acid and malic acid (stereospecificity unspecified) now receive the same registry number and
CA index name: 6915-15-7, butanedioic acid, hydroxy-. The registry number for the dl-form 617-48-1
will in the future be cross-referenced to the registry number of the nonstereospecific form 6915-15-7.
Racemates having more than one chiral center are indexed, registered, and named as having only
relative stereochemistry. Thus, dl-threitol and threitol (absolute stereospecificity unspecified, but
having two chiral centers with the same relative configuration) now receive the same CAS registry
number and index name: 7493-90-5, 1,2,3,4-butanetetrol, (R*,R*)-. Again, the registry number for
the dl-form will be cross-referenced to the registry number of the relative-only stereospecific form.

9.1.6 Chronology
Originally the registry system covered substances mentioned in the chemical literature since
January 1965, but in the period 1984–1986, CAS assigned registry numbers to substances indexed
in the 6th (1957–1961) and 7th (1962–1966) Collective Indexes.
Because registry numbers are assigned sequentially, it is usually possible to tell from the magnitude of a number approximately when it was assigned. Approximate values for the highest CAS
registry numbers to occur in each CAS Collective Index are shown as follows:
8CI (1967–1971)
9CI (1972–1976)
10CI (1977–1981)
11CI (1982–1986)
12CI (1987–1991)
13C1 (1992–1996)
14CI (1997–2001)
15CI (2002–2006)

35061-04-2
61690-48-0
80373-21-3
106330-30-7
138463-63-5
183967-34-2
259887-14-4
915040-68-5

Thus, a substance with CAS registry number 66148-78-5 should appear for the first time in 9CI;
certainly, it will not be found in 8CI. However, while the magnitude of the CAS number indicates
when it was generated by CAS, a high number does not necessarily mean a compound new to science:
• It may be a compound from the old literature that has just been reported in the literature
for the first time since 1967.
• It may be a number added retrospectively by CAS to compounds from various data collections. In the early years of the registry system, substances from a number of special
data collections, such as the Colour Index, Merck Index, Lange’s Handbook, and Pesticide
Index, were added. Some of these substances may not have been reported subsequently.
• CAS has been working backwards through the literature assigning new registry numbers
to substances not encountered in the previous work.
• It may be a duplicate for an existing compound.
Not all of the substances that have been registered have appeared in CA abstracts or indexes.
Thus, it is quite possible to find a registry number that does not appear in any CA Substance Index.
More recently the letter P has been added to new registry numbers where the physical properties
of the substance have been reported.

9.2 InChI
These identifiers were developed as an IUPAC project in 2000–2004. They are the most recent technology aimed at an unambiguous text-string representation of chemical structures. (Earlier technologies
included Wiswesser line notation, which is not described here, and SMILES, described below.)

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InChI (pronounced “In-chee”; called IChI until 2004) stands for IUPAC International Chemical
Identifier, and was developed to enable the easy linking of diverse data compilations, whether print
or electronic. The name InChI™ is protected, but use and development of InChI identifiers is free
access, and the source code and associated documentation can be downloaded for free from www.
iupac.org/inchi. Source codes can be modified under the terms of a public licence, and IUPAC welcomes proposals for enhancements. Following beta-testing, the current version (1.02) is full release
(January 2009).
The main advantages of InChI are stated as follows:

1. They are freely usable and nonproprietary.
2.They can be computed from structure information and do not have to be assigned by
an organisation.
3.They can, with practice, be read to interpret the structure.
For example:
CH 3 CH 2 OH
ethanol

InChI=1/C2H60/c1-2-3/h3H,
,2H2,1H3

See also www.iupac.org/inchi for an extensive website on InChIs and wwmm.ch.cam.ac.uk/
inchifaq for a FAQ website..

9.3 Simplified Molecular Input Line Entry System (SMILES)
SMILES is a line notation developed in the 1980s and since modified and extended by others, particularly Daylight Chemical Information Systems, Inc.
See Weininger, D., J. Chem. Inf. Comput. Sci., 28, 31–36, 1988; 29, 97–101, 1989.
Using simple rules, a structure is represented by a string of characters unique to that structure.
It can also be used to specify stereochemistry at double bonds and chiral centres. SMARTS is a
further extension that allows substructure searching.
For example:
CC(O)O
c1ccccc1
C1CCCCC1
CCN(CC)CC
F/CC\F
F/CC/F

Acetic acid
Benzene
Cyclohexane
Triethylamine
Z-Difluoro ethane
E-Difluoroethene

SMILES strings may be converted back to two-dimensional structures using structure diagram
generation programs, of which there are several on the market.
See Helson, H. E., Structure diagram generation, in Reviews in Computational Chemistry, ed.
K. B. Lipkowitz and D. B. Boyd (New York: Wiley-VCH, 1999), pp. 313–398.
SMILES was designed, however, such that it could be written or read without the use of a computer. Its advantage is that it is easier to interpret in this way than InChI.

10 Molecular Formulae
10.1 The Hill System
In most publications, including Chemical Abstracts and Beilstein, molecular formulae are given in
Hill system order. For organic compounds, the order is C first, then H, and then the remaining element symbols alphabetically. For compounds that do not contain carbon, the element symbols are
ordered alphabetically (see Hill, E. A., J. Am. Chem. Soc., 22, 478–490, 1900).
Although the Hill system is now used almost exclusively, other systems have been used in the
past. For example, the early formula indexes to Beilstein used the Richter system, in which the elements are cited in the order C, H, O, N, Cl, Br, I, F, S, P.

10.2 Chemical Abstracts Conventions
Users of Chemical Abstracts may occasionally have difficulty in locating certain types of compounds. For example, sodium acetate will not be found under C2H3NaO2; it appears under C2H4O2,
which is the formula of the parent acid (acetic acid). The conventions that Chemical Abstracts uses
include the following:
• Metal salts of acids, alcohols, and amines are indexed at the molecular formulae of the
parent acids, alcohols, and amines. Thus, sodium ethoxide appears under C2H6O (ethanol)
and not under C2H5NaO.
• Acid salts of amines (and other basic parents) are indexed at the molecular formulae of the
amines. Thus, methanamine hydrochloride appears under CH5N (methanamine) and not
under CH6ClN.
• Counterions of -onium compounds are not included in the formula heading. Thus, 1-methyl
pyridinium chloride appears under C6H8N (1-methylpyridinium) and not under C6H8ClN.
• Molecular addition compounds are indexed under the formulae of their components (except
that entries are not made for a few common components). Thus, the 1:1 addition compound
of ethanol with sulfinylbis(methane) (dimethyl sulfoxide (DMSO)) appears at C2H6O (ethanol) and at C2H6OS (sulfinylbismethane) and not at C4H12O2S.

10.3 Checking Molecular Formulae
When working out the molecular formula of a neutral organic compound, it is useful to remember
that there must be an even number of odd-valent atoms (e.g., H, halogens, N, P). Thus, the formula
C27H45O is obviously incorrect unless it is a radical.
A more sophisticated check on the accuracy of a formula is to calculate the number of rings/
double bonds in the compound from the formula. You can then count the number of rings and
double bonds and compare it with the results of the calculation.
If H = number of univalent atoms (H, halogen), N = number of trivalent atoms (N, P), and C =
number of tetravalent atoms, then

Number of rings/double bonds = ½ (2C – H + N) + 1

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For example, consider the following:
O

H
N

N
N

The following rapid method can be used to check the hydrogen count in a structure without using
a computer, for example:
Formula C10H11N3O.
Number of C atoms × 2 = 20.
Deduct 2 for each ring apart from the first (minus 2) and 2 for each double bond (including
CO) (minus 10), leaves 8.
Add 1 for each N, gives 11.
Note the following:
• The number of divalent atoms (O,S) does not affect the calculation. These must be checked
by inspection.
• Triple bonds, including cyano, count as two doubles (subtract 4).
• Do not forget to count every ring, e.g., in a bicyclic structure.

Hazard Information
11 Chemical
for the Laboratory
Rupert Purchase
Two types of hazards are associated with the use of chemicals—hazards that are a direct result of
the physical and reactive properties of a chemical, and health hazards resulting from the biological properties. This chapter summarises hazards that are associated with working with chemicals
in a laboratory, and highlights some sources of hazard information for carrying out hazard and
risk assessments.
Lack of hazard information does not mean that the consequences of handling a chemical can be
disregarded. Any chemical has the capacity for harm if it is carelessly used, and for many newly
synthesised materials (e.g., new synthetic reagents), hazardous properties may not be apparent or
may not have been cited in the literature. The toxicity of some very reactive chemicals may not have
been evaluated because of ethical considerations.
Good laboratory and manufacturing practices are encoded in national and international health
and safety legislation, and place emphasis on the key attitudes to be adopted when working with
chemical substances (or mixtures). Although the exact regulatory details may differ from country
to country, the essential aims of national health and safety legislation relating to the handling of
chemicals in laboratories (and in the workplace in general) are the same and emphasise the importance of hazard information:
• Identify the risks of handling hazardous substances and inform employees.
• Prevent, minimise, or control exposure.
• Ensure that control measures are correctly used and maintained, and that personal protection equipment is available.
• Monitor exposure in the workplace and comply with national occupational exposure limits.
• Provide information, training, and instruction of the risks involved.
• Keep records of risk assessments, records of the maintenance and testing of engineering
controls, and occupational health records.

11.1 Hazard and Risk Assessment
11.1.1 Definitions
Hazard is the set of inherent properties of a chemical substance that make it capable of causing
adverse effects in people or the environment when a particular degree of exposure occurs. Risk is
the predicted or actual frequency of occurrence of an adverse effect of a chemical substance from a
given exposure to humans or the environment.
Risk assessment therefore requires knowledge of both the hazard of a chemical and the purpose
for which it is being used. A highly hazardous substance presents a very low risk if it is securely
contained with no likely exposure. Conversely, a substance of relatively low hazard may present
unacceptable risks if extensive exposure can occur. Both hazard and exposure must be considered
before the risk can be adequately assessed.
169

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11.1.2 Legislation
In the UK the Control of Substances Hazardous to Health (COSHH) Regulations 2002 oblige
laboratory managers and supervisors (and employers in general) to assess the risks to health from
hazardous substances used in or created by workplace activities.
The Chemicals (Hazard Information and Packaging for Supply) (CHIP) Regulations 2009 require
manufacturers and suppliers to provide users with information about hazards and health risks by
labelling their products with relevant hazard information and by issuing Material Safety Data Sheets.
Other relevant legislation is the Health and Safety at Work Act 1974, the Management of Health
and Safety at Work Regulations 1999, and the Ionising Radiation Regulations 1999.
For information on all of these, see http://www.opsi.gov.uk/stat. UK health and safety legislation is subject to amendments, updates, and harmonisation with internationally agreed health and
safety directives.

11.1.3 Workplace Exposure Limits
Workplace exposure limits (WELs) were adopted in the UK in 2005 to replace maximum exposure
limits (MELs) and occupational exposure standards (OESs). Workplace exposure limits—longterm exposure limits (eight-hour time-weighted average exposures) and short-term exposure limits
(Â�fifteen-minute time-weighted average exposures)—are set by the Health and Safety Executive
(HSE) and published in document EH40 (http://www.hse.gov.uk/coshh/table1.pdf).
Recommendations for controlling and monitoring substances assigned WELs are part of the
COSHH Regulations 2002. Exposure limits are also set by other regulatory and advisory bodies,
e.g., threshold limit values (TLVs) by the American Conference of Governmental Industrial
Hygienists (ACGIH) and Maximale Arbeitsplatzkonzentrationen (MAK) by German authorities. In
EH40, the route of exposure is mainly by inhalation, but exposure limits are also assigned to some
substances that are easily absorbed by the skin or are skin sensitizers.

11.2 Physical and Reactive Chemical Hazards
Chemicals that present a particular hazard in the laboratory as a result of their physical and reactive
properties include the following categories, identified for the purposes of risk assessment and for
product labelling in UK and European Union (EU) health and safety regulations:
•
•
•
•
•
•
•
•

Flammable chemicals (Section 11.7)
Pressurized gases
Shock-sensitive explosive chemicals (Table11.1)
Water-reactive chemicals (Table11.2)
Pyrophoric chemicals (Table11.3)
Peroxide-forming chemicals (Tables11.11 and 11.12)
Oxidants (and reductants)
Strong acids (and strong bases)

Additionally, the incompatibility of many of these groups of chemicals presents further hazards
in experimental work, and for their safe storage and disposal.

11.3 Health Hazards
The following groups of chemicals present health hazards for laboratory workers and others in the
working environment, and are differentiated for the purposes of risk assessment and for product
labelling in UK and EU health and safety regulations:

Chemical Hazard Information for the Laboratory

171

Table11.1
Some Shock-Sensitive Compounds
Acetylenic compounds, especially polyacetylenes, haloacetylenes, and heavy metal salts of acetylenes (copper, silver, and
mercury salts are particularly sensitive)
Acyl nitrates
Alkyl and acyl nitrites
Alkyl chlorates
Alkyl nitrates, particularly polyol nitrates such as nitrocellulose and nitroglycerine
Amine metal oxosalts: metal compounds with coordinated ammonia, hydrazine, or similar nitrogenous donors and ionic
chlorate(VII), nitrate(V), manganate(VII), or other oxidizing group
Azides, including metal, nonmetal, and organic azides
Chlorate(III) salts of metals
Chlorate(VII) salts: most metal, nonmetal, amine, and organic cation chlorates(VII) can be detonated or undergo violent
reaction in contact with combustible materials
Diazo compounds such as CH2N2
Diazonium salts, when dry
Fulminates
Hydrogen peroxide becomes increasingly treacherous as the concentration rises above 30%, forming explosive mixtures
with organic materials and decomposing violently in the presence of traces of transition metals
N-Halogen compounds such as difluoroamino compounds and halogen azides
N-Nitro compounds such as N-nitromethylamine, nitrourea, nitroguanidine, and nitric amide
Oxo salts of nitrogenous bases: chlorates(VII), dichromates(VI), nitrates(V), iodates(V), chlorates(III), chlorates(V), and
manganates(VII) of ammonia, amines, hydroxylamine, guanidine, etc.
Peroxides and hydroperoxides, organic
Peroxides (solid) that crystallize from or are left from evaporation of peroxidizable solvents
Peroxides, transition metal salts
Picrates, especially salts of transition and heavy metals, such as Ni, Pb, Hg, Cu, and Zn; picric acid is explosive but is less
sensitive to shock or friction than its metal salts and is relatively safe as a water-wet paste
Polynitroalkyl compounds such as tetranitromethane and dinitroacetonitrile
Polynitroaromatic compounds, especially polynitro hydrocarbons, phenols, and amines
Source: Reproduced with permission from IUPAC-IPCS, Chemical Safety Matters (Cambridge: Cambridge University
Press, 1992).

• Human carcinogens and probable human carcinogens according to the International
Agency for Research on Cancer (IARC) classifications (IARC Monographs on the
Evaluation of Carcinogenic Risks to Humans: Overall Evaluations of Carcinogenicity:
An Updating of IARC Monographs Volumes 1 to 42, Suppl. 7 (Lyon: IARC, 1987); available online)
• Human teratogens and chemicals that have an effect on human reproduction
• Chemicals that are irritants to the skin, eyes, and respiratory system (data from human
exposure or animal tests)
• Chemicals that are corrosive to the skin, eyes, and respiratory system (data from human
exposure or animal tests)
• Skin sensitizers
• Chemicals with known target organ toxicity or toxicity due to a specific pharmacological mechanism
• Mutagenic chemicals
• Chemicals classified as very toxic or extremely toxic on the basis of acute toxicity data

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Table11.2
Some Water-Reactive Chemicals
Alkali metals
Alkali metal hydrides
Alkali metal amides
Metal alkyls
Grignard reagents
Halides of nonmetals, e.g., BCl3, BF3, PCl3, PCl5, SiCl4, S2Cl2
Inorganic acid halides, e.g., POCl3, SOCl2, SO2Cl2
Anhydrous metal halides
Phosphorus(V) oxide
Calcium carbide
Organic acid halides and anhydrides of low molecular weight
Source: Reproduced with permission from IUPAC-IPCS,
Chemical Safety Matters (Cambridge: Cambridge Uni
versity Press, 1992).

Table11.3
A Partial List of Pyrophoric Chemicals
Grignard reagents RMgX
Metal alkyls and aryls, e.g., RLi, RNa, R3Al, R2Zn
Metal carbonyls
Alkali metals, e.g., Na, K
Metal powders, e.g., Al, Co, Fe, Mg, Mn, Pd, Pt, Sn, Ti, Zn, Zr
Metal hydrides, e.g., NaH, LiAlH4
Nonmetal hydrides, e.g., B2H6 and other boranes, PH3, AsH3
Nonmetal alkyls, e.g., R3B, R3P, R3As
Phosphorus (white)
Source: Reproduced with permission from IUPAC-IPCS,
Chemical Safety Matters (Cambridge: Cambridge Uni
versity Press, 1992).

The toxicological criteria that are used for these classifications are described by Bender, H. F.,
et al., Hazardous Chemicals: Control and Regulation in the European Market (Weinheim: WileyVCH, 2007).
The health and other hazards associated with solvents are described in Section 11.7.

11.4 Handling and Storage of Chemicals
Hazard data influence the way a chemical should be handled, contained, stored, and ultimately
discarded. The safe storage of chemicals requires planning and an appreciation of those chemicals
that are incompatible (see Section 11.5). Chemical storage is briefly reviewed in Chemical Safety
Matters, IUPAC-IPCS, Cambridge University Press, Cambridge, 1992, and a longer account (with a
mainly North American regulatory perspective) is given in Safe Storage of Laboratory Chemicals,
2nd edn, ed. D.A. Pipitone, Wiley, New York, 1991.
Chemical Safety Matters also provides useful advice on the precautions to be taken when handling those chemicals that present special problems in a laboratory, e.g., substances that have a high

Chemical Hazard Information for the Laboratory

173

acute toxicity or are known to be human carcinogens or can cause other chronic toxic effects. A
more detailed appraisal of the problems of handling carcinogens may be found in Safe Handling of
Chemical Carcinogens, Mutagens, Teratogens and Highly Toxic Substances, Vols. 1 and 2, ed. D.B.
Walters, Ann Arbor Science, Michigan, 1980, and in Castegnaro, M. et al., Chemical Carcinogens:
Some Guidelines for Handling and Disposal in the Laboratory, Springer, Berlin, 1986.
Awareness of very reactive chemicals is essential. Advice on handling highly flammable and/or
potentially explosive reagents is provided in the IUPAC-IPCS book Chemical Safety Matters, and
the properties of many common but hazardous laboratory chemicals are succinctly summarised in
the ‘yellow pages’ section of Hazards in the Chemical Laboratory, 5th edn., ed. S.G. Luxon, Royal
Society of Chemistry, Cambridge, 1992. One particular explosive hazard, peroxide-forming chemicals, is described in more detail in Section 11.8.

11.4.1 Gases
Handling gases poses special problems for laboratory personnel, from the correct way to store,
transport, and use compressed gas cylinders to the dangers from water being sucked back into the
cylinders of hydrolysable gases. Chemical Safety Matters provides sound practical advice on using
gases. Hazards in the Chemical Laboratory contains summaries of the hazardous and toxic properties of commonly used laboratory gases. See also Yaws, C. L., Matheson Gas Data Book, 7th ed.
(Matheson Tri-Gas, NJ: McGraw-Hill, 2001); Effects of Exposure to Toxic Gases—First Aid and
Medical Treatment, 3rd ed., ed. F. Scornavacca et al. (Secausus, NJ: Matheson Gas Products, 1988).
The use of liquefied gases presents additional hazards, e.g., the use and disposal of liquid nitrogen,
which can be contaminated with liquid oxygen.

11.5 Hazardous Reaction Mixtures
The potential for chemicals to interact in a violent and uncontrolled manner should be foremost in
the mind of everyone concerned with the planning and execution of chemical operations. Not only
can syntheses and purifications go disastrously wrong if the elementary principles of chemistry
are overlooked, but the inadequate storage of incompatible chemicals has led to many a gutted and
blackened factory, warehouse and laboratory.
Luckily for the laboratory chemist, many of these mishaps of yesteryear have been collated, most
notably (and authoritatively) by Leslie Bretherick. Bretherick’s Handbook of Reactive Chemical
Hazards, which by 2006 had reached its 7th edition, details the predictable and the unexpected
from the literature of reactive chemical hazards. In a review, published in Hazards in the Chemical
Laboratory, 5th edn, ed. S.G. Luxon, Royal Society of Chemistry, Cambridge, 1992, Bretherick has
also summarised some frequently encountered incompatible chemicals that present either a reactive
hazard or a toxic hazard if combined. These two lists are reprinted here as Tables 11.4 and 11.5 by
kind permission of the Royal Society of Chemistry. In addition, potentially explosive combinations of
some commonly-encountered laboratory reagents are shown in Table 11.6 (reproduced with permission from Chemical Safety Matters, IUPAC-IPCS, Cambridge University Press, Cambridge, 1992).

11.6 Disposal of Chemicals
Careful disposal is required in three commonly encountered situations in laboratories:
• The containment of accidental spillages of chemicals
• The disposal of residues from syntheses in which organometallic reagents were used (toxic,
pyrophoric, water reactive, and flammable hazards)
• The disposal of column chromatographic materials and any absorbed residues (toxic, particulate, and flammable hazards)

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Organic Chemist's Desk Reference, Second Edition

Table11.4
A Partial List of Incompatible Chemicals—Reactive Hazards
Substances in the left-hand column should be stored and handled so that they cannot possibly accidentally contact
corresponding substances in the right-hand column under uncontrolled conditions, when violent reactions may occur.
Acetic acid
Acetic anhydride
Acetone
Acetylene
Alkali and alkaline-earth metals,
such as sodium, potassium,
lithium, magnesium, calcium
Aluminium powder
Ammonia, anhydrous
Ammonium nitrate
Aniline
Bromine
Calcium oxide
Carbon activated
Chlorates
Chromic acid and chromium
trioxide
Chlorine
Chlorine dioxide
Copper
Fluorine
Hydrazine
Hydrocarbons (benzene, butane,
propane, gasoline, turpentine, etc.)
Hydrogen cyanide
Hydrogen fluoride
Hydrogen peroxide
Hydrogen sulfide
Iodine
Mercury
Nitric acid (concentrated)
Nitromethane, lower nitroalkanes
Oxalic acid
Oxygen
Perchloric acid
Peroxides, organic

Chromic acid, nitric acid, peroxides, and permanganates
Hydroxyl-containing compounds, ethylene glycol, perchloric acid
Concentrated nitric and sulfuric acid mixtures, hydrogen peroxide
Chlorine, bromine, copper, silver, fluorine, and mercury
Carbon dioxide, carbon tetrachloride, and other chlorinated hydrocarbons (also
prohibit water, foam, and dry chemicals on fires involving these metals—dry sand
should be available)
Halogenated or oxygenated solvents
Mercury, chlorine, calcium hypochlorite, iodine, bromine, and hydrogen fluoride
Acids, metals powder, flammable liquids, chlorates, nitrites, sulphur, finely divided
organics or combustibles
Nitric acid, hydrogen peroxide
Ammonia, acetylene, butadiene, butane and other petroleum gases, sodium carbide,
turpentine, benzene, and finely divided metals
Water
Calcium hypochlorite, other oxidants
Ammonium salts, acids, metal powders, phosphorus, sulfur, finely divided organics
or combustibles
Acetic acid, naphthalene, camphor, glycerol, turpentine, alcohol, and other
flammable liquids
Ammonia, acetylene, butadiene, butane, other petroleum gases, hydrogen, sodium
carbide, turpentine, benzene, and finely divided metals
Ammonia, methane, phosphine, and hydrogen sulfide
Acetylene, hydrogen peroxide
Isolate from everything
Hydrogen peroxide, nitric acid, any other oxidant, heavy metal salts
Fluorine, chlorine, bromine, chromic acid, concentrated nitric acid, peroxides
Nitric acid, alkalis
Ammonia, aqueous or anhydrous
Copper, chromium, iron, most metals or their salts, any flammable liquid,
combustible materials, aniline, nitromethane
Fuming nitric acid, oxidising gases
Acetylene, ammonia (anhydrous or aqueous)
Acetylene, fulminic acid,a ammonia
Acetic acid, acetone, alcohol, aniline, chromic acid, hydrogen cyanide, hydrogen
sulfide, flammable liquids, flammable gases, nitratable substances, fats, grease
Inorganic bases, amine, halogens, 13X molecular sieve
Silver, mercury, urea
Oils, grease, hydrogen, flammable liquids, solids, or gases
Acetic anhydride, bismuth and its alloys, alcohol, paper, wood, grease, oils,
dehydrating agents
Acids (organic or mineral, avoid friction, store cold)

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Chemical Hazard Information for the Laboratory

Table11.4 (continued)
A Partial List of Incompatible Chemicals—Reactive Hazards
Phosphinates
Phosphorous (white)
Potassium chlorate
Potassium perchlorate
Potassium permanganate
Silver

Any oxidant
Air, oxygen
Acids (see also chlorates)
Acids (see also perchloric acid)
Glycerol, ethylene glycol, benzaldehyde, sulfuric acid
Acetylene, oxalic acid, tartaric acid, fulminic acid,a ammonium compounds

Sodium
Sodium nitrite
Sodium peroxide

See alkali metals (above)
Ammonium nitrate and other ammonium salts
Any oxidisable substrate, such as ethanol, methanol, glacial acetic acid, acetic
anhydride, benzaldehyde, carbon disulfide, glycerol, glycerol, ethylene glycol,
ethyl acetate, methyl acetate, and furfural
Chlorates, perchlorates, permanganates
Metal nitrates, nitrites, oxidants
Perchlorate salts

Sulfuric acid
Thiocyanates
Trifluoromethanesulfonic acid

Source: Reproduced with permission from L. Bretherick, Hazards in the Chemical Laboratory, ed. S.G. Luxon (Cambridge:
Royal Society of Chemistry, 1992).
a Produced in nitric acid–ethanol mixtures.

Table11.5
A Partial List of Incompatible Chemicals—Toxic Hazards
Substances in the left-hand column should be stored and handled so that they cannot possibly
accidentally contact corresponding substances in the centre column, because toxic materials
(right-hand column) would be produced.
Arsenical materials
Azides
Cyanides
Hypochlorites
Nitrates
Nitric acid
Nitrites
Phosphorus
Selenides
Sulfides
Tellurides

Any reducing agenta
Acids
Acids
Acids
Sulfuric acid
Copper, brass, any heavy metals
Acids
Caustic alkalis or reducing agents
Reducing agents
Acids
Reducing agents

Arsine
Hydrogen azide
Hydrogen cyanide
Chlorine or hypochlorous acid
Nitrogen dioxide
Nitrogen dioxide (nitrous fumes)
Nitrous fumes
Phosphine
Hydrogen selenide
Hydrogen sulfide
Hydrogen telluride

Source: Reproduced with permission from L. Bretherick, Hazards in the Chemical Laboratory,
ed. S.G. Luxon (Cambridge: Royal Society of Chemistry, 1992).
a Arsine has been produced by putting an arsenical alloy into a wet galvanized bucket.

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Table11.6
Potentially Explosive Combinations of Some Common Reagents
Acetone with chloroform in the presence of base
Acetylene with copper, silver, mercury, or their salts
Ammonia (including aqueous solutions) with C12, Br2, or I2
Carbon disulfide with sodium azide
Chlorine with an alcohol
Chloroform or carbon tetrachloride with powdered Al or Mg
Decolorizing carbon with an oxidizing agent
Diethyl ether with chlorine (including a chlorine atmosphere)
Dimethyl sulfoxide with an acyl halide, SOCl2, or POCl3 or with CrO3
Ethanol with calcium chlorate or silver nitrate
Nitric acid with acetic anhydride or acetic acid
Picric acid with a heavy metal salt, such as of Pb, Hg, or Ag
Silver oxide with ammonia with ethanol
Sodium with a chlorinated hydrocarbon
Sodium chlorate with an amine
Source: Reproduced with permission from IUPAC-IPCS, Chemical Safety Matters
(Cambridge: Cambridge University Press, 1992).

An account of the safe disposal of laboratory chemicals is given in Pitt, M. J., et al., Handbook of
Laboratory Waste Disposal (Chichester: Ellis Horwood, 1985). Detailed experimental procedures
have been published on how to convert particularly reactive and toxic substances into less harmful products before their disposal; see, for example, Hazardous Laboratory Chemicals Disposal
Guide, 3rd ed., ed. M.-A. Armour (Boca Raton, FL: CRC Press, 2003). Destruction of Hazardous
Chemicals in the Laboratory, 2nd ed., ed. G. Lunn et al. (New York: Wiley, 1994) contains methods
for the degradation and disposal of the following chemicals:
Acid halides and anhydrides
Aflatoxins
Alkali and alkaline-earth metals
Alkali-metal alkoxides
Antineoplastic alkylating agents
Aromatic amines
Azides
Azo and azoxy compounds and tetrazenes
Biological stains
Boron trifluoride and inorganic fluorides
Butyllithium
Calcium carbide
Carbamic acid esters
Chloromethylsilanes and silicon
tetrachloride
N-Chlorosuccinimide
Chlorosulfonic acid
Cr(VI)
Cisplatin
Citrinin

Complex metal hydrides
Cyanides and cyanogen bromide
Cycloserine
Dichloromethotrexate, vincristine, and
vinblastin
Diisopropyl fluorophosphate
Dimethyl sulfate and related compounds
Doxorubicin and daunorubicin
Drugs containing hydrazine and triazene
groups
Ethidium bromide
Haloethers
Halogenated compounds
Halogens
Heavy metals
Hexamethylphosphoramide
Hydrazines
Hypochlorites
Mercury
Methotrexate

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Chemical Hazard Information for the Laboratory

2-Methylaziridine
l-Methyl-4-phenyl-l,2,3,6-tetrahydro
pyridine (MPTP)
Mitomycin C
4-Nitrophenol
N-Nitrosamines and N-nitrosamides
Nitrosourea drugs
Ochratoxin A
Organic nitriles
OsO4
Patulin
Peracids
Peroxides and hydroperoxides

Phosgene
Phosphorus and P4O10
Picric acid
Polycyclic aromatic and heterocyclic
hydrocarbons
KMnO4
β-Propiolactone
Protease inhibitors
NaNH2
Sterigmatocystin
Sulfonyl fluoride enzyme inhibitors
6-Thioguanine and 6-mercaptopurine
Uranyl compounds

Methods for the conversion of the major classes of chemical carcinogens into nonmutagenic
residues are also described by Castegnaro, M., et al., Chemical Carcinogens: Some Guidelines for
Handling and Disposal in the Laboratory (Berlin: Springer, 1986).
Disposal methods for some of the more common classes of organic compounds may be found in
Chemical Safety Matters (hydrocarbons; halogenated hydrocarbons; alcohols and phenols; ethers,
thiols, and organosulfur compounds; carboxylic acids and derivatives; aldehydes; ketones; amines;
nitro and nitroso compounds; and peroxides).

11.7 Solvents
Solvents are fire and health hazards, and caution is necessary when using these substances in a laboratory environment. The flammable properties and flammability classifications of many solvents
impose restrictions on their handling and storage. Particular concerns are vapour leaks of solvents
as sources of ignition, and the inappropriate storage of Winchester bottles containing solvents (especially if exposed to sunlight, which can result in peroxidation) in laboratories. The peroxidation of
solvents during storage as a reactive hazard is described in more detail in Section 11.8. Both acute
and chronic low-level exposures contribute to the recognised health hazards of solvents.

11.7.1 Flammability Classifications
Flammability classifications of solvents (and other chemicals) are based on flash point (fl.p.) meas
urements. Flash point is the lowest temperature at which a liquid has sufficient vapour pressure to
form an ignitable mixture with air near the surface of the liquid. The following criteria currently
apply (CHIP Regulations 2009):
Extremely flammable: liquids with fl.p. < 0°C and Bp ≤ 35°C
Highly flammable: fl.p. ≥ 0°C and < 21°C
Flammable: fl.p. ≥ 21°C and < 55°C
Substances with fl.p. > 55°C should be regarded as combustible if brought to a high temperature.
By 2015 the United Nations Globally Harmonized System of Classification and Labelling of
Chemicals (GHS) will replace these categories. The GHS system divides flammable liquids into
four new categories:
Category 1: fl.p. < 23°C and initial Bp ≤ 35°C
Category 2: fl.p. < 23°C and initial Bp > 35°C
Category 3: fl.p. ≥ 23°C and ≤ 60°C
Category 4: fl.p. > 60°C and ≤ 93°C

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Flammable substances used and stored in the laboratory are also subject to further risk assessment and control in UK law under the the Health and Safety at Work Act 1974, the Management
of Health and Safety at Work Regulations 1999, the COSHH Regulations 2002, the Dangerous
Substances and Explosive Atmospheres Regulations 2002 (DSEAR), and the Regulatory Reform
(Fire Safety) Order 2005.
Flammability classifications for a selection of solvents (and some other substances) are
given in Table11.7. The chemicals are listed in order of increasing boiling point to the nearest
1°C. Solvents in Table 11.7 that are also peroxidation hazards may be identified from data in
Tables11.11 and 11.12.

11.7.2 Health Hazards
Apart from the acute toxic effects of high concentrations of the more volatile solvents, there are
health hazards from the long-term (chronic) exposure to low levels of solvents. Reproductive
effects that are associated with chronic exposure to some solvents used in laboratories are shown
in Table11.8. Evidence from animal studies suggests there are reproductive hazards from handling
other solvents. For example:
• 2-Ethoxyethanol and 2-butanone are teratogenic (in animal models).
• Dichloromethane, styrene, 1,1,1-trichloroethane, tetrachloroethylene, and xylene isomers
have foetotoxic properties (in animal models).
The IARC classifications for the carcinogenic risk from exposure to some laboratory solvents
(and other selected reagents) are summarised in Table11.9. Other toxic effects for classes of solvents
categorised by functional group are given in Table11.10.
Solvents that are currently assigned a workplace exposure limit (eight-hour long-term exposure
limit) that is less than or equal to 100 ppm are marked in Table11.7 with an arrowhead (►) (data
from EH40/2005).

11.8 Peroxide-Forming Chemicals
Peroxide-forming solvents and reagents should be dated at the time they are first opened, and should
be either discarded or tested for peroxides within a fixed period of time after their first use. Peroxides
can be detected with NaI/AcOH, though dialkyl peroxides may need treatment with concentrated
HCl or 50% H2SO4 before detection with iodide is possible. A commercially available test paper,
which contains a peroxidase, can detect hydroperoxides and dialkyl peroxides, as well as oxidizing
anions, in organic and aqueous solvents.
The types of structures that have been identified as likely to produce peroxides are listed in
Table11.11, and some common peroxidisable chemicals are given in Table11.12.
Hydroperoxides, but not dialkyl peroxides, can be removed from peroxide-forming solvents by
passage through basic activated alumina, by treatment with a self-indicating activated molecular
sieve (type 4A) under nitrogen, or by treatment with Fe2+/H+, CuCl, or other reductants.
The following references provide further information:
Detection and removal of peroxides from solvents: Organic Solvents: Physical Properties and
Methods of Purification, 4th ed., ed. J. A. Riddick et al. (Chichester: Wiley, 1986).
Deperoxidation of ethers with molecular sieves: Burfield, D. R., J. Org. Chem., 47, 3821–
3824, 1982.
Determination of organic peroxides: Mair, R. D., et al., in Treatise on Analytical Chemistry,
ed. I. M. Kolthoff et al., Vol. 14, Part II (New York: Interscience, 1971), p. 295.

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Table11.7
Fire Hazards of Some Common Laboratory Solvents and Other Substances
Bp
(°C)
30−60
30
32
35
36
38
40
46
46
47
50
54
56
56
61
65
65
69
69
72
74
75
77
77
78
78
80
80
81
82
82
83
84
85
87
88
97
98
99
100
100
101
101
101

Mp
(°C)

Namea

−161
−99
−116
−129
−98
−97
−112
−14
−111
−94
−109
−94
−98
−63
−108
−98
−87
−94
−15
−32
−95
−84
−21
−117
−123
−86
6
6
−45
−90
26
−35
−58
−85
−45
−127
−92
−108
−115
0
11
−127
−29

Petrol
2-Methylbutane
Methyl formate
Diethyl ether
Pentane
Dimethyl sulfide
Dichloromethane
Carbon disulfide
1,1,1-Trichloro-2,2,2-trifluoroethane
1,2-Dibromo-1,1,2,2-tetrafluoroethane
Cyclopentane
2-Methoxy-2-methylpropane
Acetone
Methyl acetate
Chloroform
Tetrahydrofuran
Methanol
Diisopropyl ether
Hexane
Trifluoroacetic acid
1,1,1-Trichloroethane
1,3-Dioxolane
Ethyl acetate
Carbon tetrachloride
Ethanol
1-Chlorobutane
2-Butanone
Benzene
Cyclohexane
Acetonitrile
2-Propanol
2-Methyl-2-propanol
1,2-Dichloroethane
1,2-Dimethoxyethane
Trichloroethylene
Tetrahydropyran
1-Propanol
Heptane
2,2,4-Trimethylpentane
2-Butanol
Water
1,4-Dioxane
Methylcyclohexane
Nitromethane

Flash Point
(°C)b

►

►
►

►

►
►

►

►
►
►

►
►

►
►
►

<−51
<−19
−45
−49
−34
−30

−37
−28
−17
−9
−14
10
−28
−23

2 (oc)
−4
12
−12
−1
−11
−20
6 (oc)
12
11
13
1
−20
15
−4
−12
24
11
−4
35

Flammability Classificationc
Extremely flammable
Extremely flammable
Extremely flammable
Extremely flammable
Extremely flammable
Highly flammable
Concentrated 12−19% in air, flammable
Extremely flammable
Nonflammable
Nonflammable
Extremely flammable
Highly flammable
Highly flammable
Highly flammable
Nonflammable
Highly flammable
Highly flammable
Highly flammable
Highly flammable
Nonflammable
Nonflammable
Highly flammable
Highly flammable
Nonflammable
Highly flammable
Highly flammable
Highly flammable
Highly flammable
Highly flammable
Highly flammable
Highly flammable
Highly flammable
Highly flammable
Highly flammable
Nonflammable
Highly flammable
Highly flammable
Highly flammable
Highly flammable
Highly flammable
Nonflammable
Highly flammable
Highly flammable
Flammable
(continued on next page)

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Table11.7 (continued)
Fire Hazards of Some Common Laboratory Solvents and Other Substances
Bp
(°C)

Mp
(°C)

101
102
103
104
108
111
114
116
117
118
118
121
125
126
126
132
132
132
135
136
138
139
142
142
144
146
150
153
155
155
156
161
166
172
175
180
185
189
191
195
196
196
197
202

8
−42
15
−6
−108
−95
−36
−42
−80
−90
17
−19
−86
−77
−57
−117
10
−45
−70
−94
14
−47
−79
−98
−25
30
−51
−61
−38
−45
−31
−68
−20
−75
−42
−17
−31
18
−13
−17
−46
−43
−13
20

Namea
► Formic acid
3-Pentanone
Trimethyl orthoformate
Bromotrichloromethane
2-Methyl-1-propanol
► Toluene
► 1,1,2-Trichloroethane
► Pyridine
► 4-Methyl-2-pentanone
1-Butanol
Acetic acid
► Tetrachloroethylene
► 2-Methoxyethanol
Butyl acetate
Octane
3-Methyl-1-butanol
► 1,2-Dibromoethane
► Chlorobenzene
► 2-Ethoxyethanol
► Ethylbenzene
► 1,4-Dimethylbenzene
► 1,3-Dimethylbenzene
Isopentyl acetate
Dibutyl ether
► 1,2-Dimethylbenzene
Triethyl orthoformate
Nonane
► Dimethylformamide
Methoxybenzene
► Cyclohexanone
Bromobenzene
Diglyme
► N,N-Dimethylacetamide
► 2-Butoxyethanol
2,4,6-Trimethylpyridine
► 1,2-Dichlorobenzene
trans-Decahydronaphthalene
Dimethyl sulfoxide
Benzonitrile
1-Octanol
Trimethyl phosphate
cis-Decahydronaphthalene
► 1,2-Ethanediol
Acetophenone

Flash Point
(°C)b
69
13
15
28
4
20
17
29
39
43
22
13
43
24
44
15
25
25
25
25
17
30
30
55
52 (oc)
44
51
67
67 (oc)
61
57
66
54
95 (oc)
72
81
107
54
111
77

Flammability Classificationc
Highly flammable
Highly flammable
Nonflammable
Flammable
Highly flammable
Nonflammable
Flammable
Highly flammable
Flammable
Flammable
Nonflammable
Flammable
Flammable
Highly flammable
Flammable
Nonflammable
Flammable
Flammable
Highly flammable
Flammable
Flammable
Flammable
Flammable
Highly flammable
Flammable
Flammable
Flammable
Flammable
Flammable
Flammable
Flammable
Flammable
Flammable
Flammable
Flammable
Flammable

Flammable

181

Chemical Hazard Information for the Laboratory

Table11.7 (continued)
Fire Hazards of Some Common Laboratory Solvents and Other Substances
Bp
(°C)

Mp
(°C)

202
202
205
207
207
210
211
214
215
216
222
235
240
255
279
285
290
328

−2
−24
−15
<−50
−35
3
6
17
−12
−45
82
7
−55
72
96
27
18
−6

Namea
Hexachloro-2-propanone
► 1-Methyl-2-pyrrolidinone
Benzyl alcohol
1,3-Butanediol
1,2,3,4-Tetrahydronaphthalene
► Formamide
► Nitrobenzene
► 1,2,4-Trichlorobenzene
Dodecane
1,2-Bis(2-methoxyethoxy)ethane
Acetamide
Hexamethylphosphoric triamide
4-Methyl-1,3-dioxolan-2-one
Biphenyl
Acenaphthene
Tetrahydrothiophene 1,1-dioxide
Glycerol
Tetraethylene glycol

Flash Point
(°C)b

Flammability Classificationc
Nonflammable

96 (oc)
93
109
71
>77
88
105
74
111
>104
>55
135
113
>66
177
160
174 (oc)

Note: Carbon-, sulfur-, nitrogen-, and phosphorus-containing solvents will evolve oxides of their constituent elements,
including CO, on combustion, and these gases are toxic and probably irritants if a fire involving such materials is
encountered. Some chlorinated solvents can form phosgene (carbonyl chloride) in fires.
a ►indicates a substance currently assigned a workplace exposure limit (eight-hour long-term exposure limit) that is less
than or equal to 100 ppm (data from EH40/2005 as consolidated with amendments October 2007).
b Flash point measurements from the closed-cup method are quoted unless only data from the open-cup (oc) method are
available. Data from Stephenson, R. M., Flash Points of Organic and Organometallic Compounds (New York: Elsevier,
1987); Bond, J., Sources of Ignition (Oxford: Butterworth, 1991).
c Substances having flash points above 55°C are considered nonflammable, but may ignite if brought to a high
temperature.
d Mixture of hydrocarbons, typically 73% n-pentane, 23% branched pentanes, 3% cyclopentane. Higher boiling petrols
have correspondingly decreasing flammability hazards.

Table11.8
Reproductive Effects of Some Solvents
Reproductive Effects

Solvent(s)

Menstrual disorders
Abortion or infertility
Testicular atrophy
Decreased foetal growth, low birth weight

Toluene, styrene, benzene
Formaldehyde, benzene
2-Ethoxyethanol
Toluene, formaldehyde, vinyl chloride

Source: Reproduced with permission from Occupational Toxicology, 2nd ed., ed.
C. Winder et al. (Boca Raton, FL: CRC Press, 2004).

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Table11.9
IARC Classificationsa for Some Laboratory Solvents
Solvent

IARC Group

Benzene
Carbon tetrachloride
Chloroform
Cyclohexanone
1,2-Dichloroethane
Dichloromethane
Dimethylformamide
1,4-Dioxane
Mineral oils (untreated)
Tetrachloroethylene
Toluene
1,1,1-Trichloroethane
1,1,2-Trichloroethane
Trichloroethylene
Xylene

Group 1
Group 2B
Group 2B
Group 3
Group 2B
Group 2B
Group 3
Group 2B
Group 1
Group 2A
Group 3
Group 3
Group 3
Group 2A
Group 3

Source: Reproduced with permission from Occupational Toxicology,
2nd ed., ed. C. Winder et al. (Boca Raton, FL: CRC Press, 2004).
a IARC classifications: Group 1, agents that are carcinogenic to humans;
Group 2A, agents that are probably carcinogenic to humans; Group 2B:
agents that are possibly carcinogenic to humans; Group 3: agents that
are not classifiable; Group 4: agents that are probably not carcinogenic
to humans. From: IARC Monographs on the Evaluation of Carcinogenic
Risks to Humans: Overall Evaluations of Carcinogenicity: An Updating
of IARC Monographs Volumes 1 to 42, Suppl. 7 (Lyon: IARC, 1987);
available online.

11.9 Further Literature Sources
11.9.1 Risk and Hazard Assessment (General)
Toxic Hazard Assessment of Chemicals, ed. M. L. Richardson (London: Royal Society of
Chemistry, 1986). Definitions of risk and hazard.
King’s Safety in the Process Industries, 2nd ed., ed. R. W. King et al. (London: Arnold, 1998).
Handbook of Occupational Safety and Health, 2nd ed., ed. L. J. DiBerardinis (New York:
Wiley, 1999).
Risk Assessment of Chemicals, 2nd ed., ed. C. J. Van Leeuwen et al. (Dordrecht: Springer, 2007).

11.9.2 Physical Properties Related to Hazard
Riddick, J. A., et al., Organic Solvents: Physical Properties and Methods of Purification,
4th ed. (New York: Wiley-Interscience, 1986).
Stephenson, R. M., Flash Points of Organic and Organometallic Compounds (New York:
Elsevier, 1987).
Bond, J., Sources of Ignition (Oxford: Butterworth, 1991) (flash points, explosive limits, and
autoignition temperatures).

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Chemical Hazard Information for the Laboratory

Table11.10
Toxic Effects of Groups of Solvents
Effects
Solvent Group

Examples

Acute

Chronic

Aliphatic
hydrocarbons

Petrol, kerosene, diesel, n-hexane

Aromatic
hydrocarbons
Halogentaed
hydrocarbons

Toluene, xylene, benzene

Nausea, pulmonary
irritation, ventricular
arrhythmia
Nausea ventricular
arrhythmia, respiratory
Irritant, liver, kidney,
heart

Weight loss, anaemia,
proteinuria, haematuria,
bone marrow hypoplasia
Headache, anorexia,
lassitude
Fatigue, anorexia, liver,
kidney, cancera

Irritant, respiratory
depression
Irritant, gastrointestinal
Irritant, liver, palpitations
Kidney

Liver, immune function

Ketones
Alcohols
Esters
Glycols
Ethers
Glycols ethers

Carbon tetrachloride, dichloromethane,
trichloroethane, trichloroethylene,
tetrachloroethylene
Acetone, methyl ethyl ketone, methyl n-butyl
ketone
Methanol, ethanol, isopropanol
Methyl formate, methyl acetate, amyl acetate
Ethylene glycol, diethylene glycol,
propylene glycol
Diethyl ether, isopropyl ether
Ethylene glycol monomethyl ether, ethylene
glycol, monoethyl ether, propylene glycol
monomethyl ether

Kidney

Irritant, nausea
Irritant, nausea, anaemia,
liver, kidney,
reproductive system

Source: Reproduced with permission from Occupational Toxicology, 2nd ed., ed. C. Winder et al. (Boca Raton, FL: CRC
Press, 2004).
a In experimental animals, nongenotoxic.

Lide, D. R., Handbook of Organic Solvents (Boca Raton, FL: CRC Press, 1995).
Verschueren, K., Handbook of Environmental Data on Organic Chemicals, 4th ed.
(Chichester: Wiley, 2001).
Yaws, C. L., Matheson Gas Data Book, 7th ed. (New York: McGraw-Hill, 2001).
Kirk-Othmer’s Encyclopedia of Chemical Technology, 5th ed. (New York: Wiley, 2004–2007).

11.9.3 Occupational Exposure Limits
Occupational Exposure Limits for Airborne Toxic Substances, 3rd ed. (Geneva: ILO, 1991)
(data from sixteen countries).
EH40/2005 Workplace Exposure Limits (Norwich: HSE Books, 2005; available online with
updates http://www.hse.gov.uk/coshh/table1.pdf).
2009 TLVs® and BEIs®, American Conference of Governmental Industrial Hygienists,
Ohio, 2009.
List of MAK and BAT Values 2005 (Weinheim: Deutsche Forschungsgemeinschaft, WileyVCH, 2005).

11.9.4 Reactive Hazards
Jackson, H. L., et al., J. Chem. Ed., 47, A175, 1970 (peroxidizable compounds).
Hazards in the Chemical Laboratory, 5th ed., ed. S. G. Luxon (Cambridge: Royal Society of
Chemistry, 1992).
IUPAC-IPCS, Chemical Safety Matters (Cambridge: Cambridge University Press, 1992).
Kelly, R. J., Chem. Health Saf., 3, 28–36, 1996 (peroxidizable organic compounds).

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Table11.11
Types of Chemicals That May Form Peroxides
Organic Structures
Ethers and acetals with α-hydrogen atoms
Olefins with allylic hydrogen atoms
Chloroolefins and fluoroolefins
Vinyl halides, esters, and ethers
Dienes
Vinylacetylenes with α-hydrogen atoms
Alkylacetylenes with α-hydrogen atoms
Alkylarenes that contain tertiary hydrogen atoms
Alkanes and cycloalkanes that contain tertiary hydrogen atoms
Acrylates and methacrylates
Secondary alcohols
Ketones that contain α-hydrogen atoms
Aldehydes
Ureas, amides, and lactams that have a H atom linked to a C attached to a N
Inorganic Substances
Alkali metals, especially potassium, rubidium, and caesium
Metal amides
Organometallic compounds with a metal atom bonded to carbon
Metal alkoxides
Source: Reproduced with permission from IUPAC-IPCS, Chemical Safety
Matters (Cambridge: Cambridge University Press, 1992).

Clark, D. E., Chem. Health Saf., 8(5), 12–22, 2001 (peroxidizable organic compounds).
Pohanish, R. P., et al., Wiley Guide to Chemical Incompatibilities, 2nd ed. (New York:
Wiley, 2003).
Bretherick’s Handbook of Reactive Chemical Hazards, 7th ed., ed. P. G. Urben (Oxford:
Elsevier, 2007).

11.9.5 Toxicology
General
IARC, IARC Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to
Humans (Lyon: IARC, 1971–).
Clinical and Experimental Toxicology of Cyanides, ed. B. Ballantyne et al. (Bristol:
Wright, 1987).
Effects of Exposure to Toxic Gases—First Aid and Medical Treatment, 3rd ed., ed.
F. Scornavacca et al. (Secaucus, NJ: Matheson Gas Products, 1988).
Dangerous Properties of Industrial Materials Report, 1980–1996 (toxicological and ecotoxicological data on chemicals produced on a large scale).
Grandjean, P., Skin Penetration: Hazardous Chemicals at Work (London: Taylor & Francis,
1990) (three hundred chemicals that are toxic by skin absorption).
Patty’s Industrial Hygiene and Toxicology, 5th ed. (Hoboken, NJ: Wiley, 2001).

185

Chemical Hazard Information for the Laboratory

Table11.12
Common Peroxide-Forming Chemicals
Severe peroxide hazard on storage with exposure to air. Discard within 3 months.
Diisopropyl ether
Sodium amide (sodamide)
Vinylidene chloride (1,1-dichloroethylene)a
Divinylacetylenea
Potassium metal
Potassium amide
Peroxide hazard on concentration: Do not distil or evaporate without first testing for the
presence of peroxides. Discard or test for peroxides after 6 months.
Acetaldehyde diethyl acetal (1,1-diethoxyethane)
Ethylene glycol dimethyl ether (glyme)
Cumene (isopropylbenzene)
Ethylene glycol ether acetates
Cyclohexene
Ethylene glycol monoethers (cellosolves)
Cyclopentene
Furan
Decalin (decahydronaphthalene)
Methylacetylene
Diacetylene (1,2-butadiyne)
Methylcyclopentane
Dicyclopentadiene
Methyl isobutyl ketone
Diethyl ether (ether)
Tetrahydrofuran
Diethylene glycol dimethyl ether (diglyme)
Tetralin (tetrahydronaphthalene)
Dioxan/dioxolan (dioxane)
Vinyl ethersa
Hazard or rapid polymerization initiated by internally formed peroxides.a
(A) Normal liquids. Discard or test for peroxides after 6 months.b
Chloroprene (2-chloro-1,3-butadiene)c
Vinyl acetate
Styrene
Vinylpyridine
(B) Normal gases. Discard after 12 months.d
Butadienec
Tetrafluoroethylenec

Vinylacetylenec
Vinyl chloride

Source: Reproduced with permission from IUPAC-IPCS, Chemical Safety Matters (Cambridge:
Cambridge University Press, 1992).
a Monomers may polymerize and should be stored with a polymerization inhibitor from which
the monomer can be separated by distillation just before use.
b Although common acrylic monomers such as acrylonitrile, acrylic acid, ethyl acrylate, and
methyl methacrylate can form peroxides, they have not been reported to develop hazardous
levels in normal use and storage.
c The hazard from peroxide formation in these compounds is substantially greater when they are
stored in the liquid phase.
d Although air cannot enter a gas cylinder in which gases are stored under pressure, these gases
are sometimes transferred from the original cylinder to another in the laboratory, and it is difficult to be sure that there is no residual air in the receiving cylinder. An inhibitor should be put
into any secondary cylinder before transfer. The supplier can suggest an appropriate inhibitor
to be used. The hazard posed by these gases is much greater if there is a liquid phase in the
secondary container. Even inhibited gases that have been put into a secondary container under
conditions that create a liquid phase should be discarded within 12 months.

186

Organic Chemist's Desk Reference, Second Edition

Occupational Toxicology, 2nd ed., ed. C. Winder et al. (Boca Raton, FL: CRC Press, 2004).
Proctor and Hughes’ Chemical Hazards of the Workplace, 5th ed., ed. G. J. Hathaway et al.
(Hoboken, NJ: Wiley, 2004).
Comprehensive Toxicology, ed. I. G. Sipes et al. (New York: Elsevier, 1996).
Lewis, R. J., Sr., Sax’s Dangerous Properties of Industrial Materials, 11th ed. (Hoboken, NJ:
Wiley, 2004).
Reproductive Toxicology
Lewis, R. J., Reproductively Active Chemicals: A Reference Guide (New York: Van NostrandReinhold, 1991).
Kolb, V. M., Ed., Teratogens, 2nd ed. (Amsterdam: Elsevier, 1993).
Shepard, T. H., Catalog of Teratogenic Agents, 9th ed. (Baltimore: The John Hopkins
University Press, 1998).
Solvent Toxicology
Solvents in Common Use: Health Risks to Workers (London: Royal Society of Chemistry, 1988).
Chemical Safety Data Sheets: Solvents, Vol. 1 (Cambridge: Royal Society of Chemistry, 1989).
Ethel Browning’s Toxicity and Metabolism of Industrial Solvents, 2nd ed., ed. R. Snyder,
Vols. 1–3 (Amsterdam: Elsevier, 1987–1992).
Henning, H., ed., Solvent Safety Sheets: A Compendium for the Working Chemist (Cambridge:
Royal Society of Chemistry, 1993).
Long-Term Neurotoxic Effects of Paint Solvents (London: Royal Society of Chemistry,
1993) (neurotoxicity).
Toxicology of Solvents, ed. M. McParland et al. (Shrewsbury, Shropshire, UK: RAPRA
Technology Ltd., 2002) (toxicity and treatment of solvent exposure for all the commonly
used laboratory solvents).
Metal Toxicology
Barnes, J. M., et al., Organometallic Chemistry Reviews, 3, 137, 1968 (toxicology of organometallic compounds).
Venugopal, B., et al., Metal Toxicity in Mammals, Vols. 1–2 (New York: Plenum Press,
1977–1978).
Biological Monitoring of Toxic Metals, ed. T. W. Clarkson (New York: Plenum Press, 1988).
Handbook on Toxicity of Inorganic Compounds, ed. H. G. Seiler (New York: M. Dekker, 1988).
Metal Neurotoxicity, ed. S. C. Bondy (Boca Raton, FL: CRC Press, 1988).
Harmful Chemical Substances: Elements in Groups I–IV of the Periodic Table and Their
Inorganic Compounds, ed. V. A. Filov et al., Vol. 1 (New York: Ellis Horwood, 1993).
Hostýnek, J. J., et al., CRC Crit. Rev. Toxicol., 23, 171, 1993 (skin effects of metals).
Metal Toxicology, ed. R. A. Goyer (San Diego: Academic Press, 1995).
Toxicology of Metals, ed. L. W. Chang (Boca Raton, FL: CRC Press, 1996).
Handbook on the Toxicology of Metals, 3rd ed., ed. G. F. Nordberg et al. (Amsterdam:
Elsevier, 2007).

11.9.6 Material Safety Data Sheets
International Chemical Safety Cards, Commission of the European Communities, Luxem
bourg (produced for the International Programme on Chemical Safety); available online.
Compendium of Safety Data Sheets for Research and Industrial Chemicals, ed. L. H. Keith,
Parts I–VI (Deerfield Park, FL: VCH, 1985–1987).

Chemical Hazard Information for the Laboratory

187

The Sigma-Aldrich Library of Chemical Safety Data, 2nd ed., ed. R. E. Lenga (Milwaukee,
WI: Sigma-Aldrich Corp., 1988).
Chemical Safety Sheets (Dordrecht: Kluwer Academic, 1991) (includes a section on the prediction of chemical handling properties from physical data).

11.9.7 Laboratory Safety
Journal of Chemical Health & Safety. Official publication of the American Chemical Society
Division of Chemical Health and Safety. Published by Elsevier B.V., Amsterdam.
Laboratory Hazards Bulletin. Published monthly by the Royal Society of Chemistry, Cambridge.
Laboratory Safety: Theory and Practice, ed. A. A. Fuscaldo (New York: Academic Press, 1980).
Degradation of Chemical Carcinogens: An Annotated Bibliography, ed. M. W. Slein et al.
(New York: Van Nostrand Reinhold, 1980).
Furniss, B. S., et al., Vogel’s Textbook of Practical Organic Chemistry, 5th ed. (Harlow, Essex:
Longman Scientific & Technical, 1989), pp. 35–51 (hazards in organic chemistry laboratories).
Lunn, G., et al., Destruction of Hazardous Chemicals in the Laboratory (New York:
Wiley, 1990).
Improving Safety in the Chemical Laboratory: A Practical Guide, 2nd ed., ed. J. A. Young
(New York: Wiley, 1991).
Safe Storage of Laboratory Chemicals, 2nd ed., ed. D. A. Pipitone (New York: Wiley, 1991).
IUPAC-IPCS, Chemical Safety Matters (Cambridge: Cambridge University Press, 1992) (useful laboratory safety advice. including storage and disposal of waste chemicals).
Hazards in the Chemical Laboratory, 5th ed., ed. S. G. Luxon (Cambridge: Royal Society of
Chemistry, 1992).
Palluzi, R. P., Pilot Plant and Laboratory Safety (New York: McGraw Hill, 1994).
Stricoff, R. S., and Walters, D. B., Handbook of Laboratory Health and Safety, 2nd ed. (New
York: J. Wiley, 1995).
Prudent Practices in the Laboratory (Washington, D.C.: National Academic Press, 1995).
Errington, R. J., Advanced Practical Inorganic and Metalorganic Chemistry (London:
Blackie Academic, 1997) (techniques for the safe handling of organometallic reagents).
Furr, A. K., CRC Handbook of Laboratory Safety, 5th ed. (Boca Raton, FL: CRC Press, 2000).
Handbook of Chemical Health and Safety, ed. R. J. Alaimo (New York: American Chemical
Society/Oxford University Press, 2001).
Wiener, J. J. M., and Grice, C. A., “Practical Segregation of Incompatible Reagents in the
Organic Chemistry Laboratory,” Org. Process Res. Dev., 13(6), 1395–1400, 2009.

11.9.8 Health and Safety Legislation
Croner’s Laboratory Manager, Croner Publications, 1997–, (revised quarterly). Provides
updated information on changes to health and safety legislation affecting the management
of laboratories.
Selwyn, N. M., The Law of Health and Safety at Work 2008/2009, 17th ed. (Kingston upon
Thames: Croner, 2009). Tolley’s Health and Safety at Work Handbook 2009, 21st ed.
(London: LexisNexis, 2009).

11.9.9 Electronic Sources for Hazard Information
The web is a vast resource for hazard information and advice on safe practices in the chemical laboratory. Many UK and U.S. university chemistry departments have posted their safety policies and
guidance for laboratory workers on the web and added links to other health and safety websites. The
websites of the following organisations are also useful sources of hazard information:

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Organisation

Internet Address and Description of Content

Agency for Toxic Substances and Disease
Registry

http://www.atsdr.cdc.gov/
Health effects information concerning chemicals, chemicals released
from hazardous waste disposal sites, physician case studies

American Conference of Governmental
Industrial Hygienists

www.acgih.org
Sources of information on TLVs, biological exposure indices,
chemicals under study, and revisions to TLVs

Health and Safety Executive (HSE)

http://www.hse.gov.uk/coshh/index.htm
COSHH home page

International Agency for Research On Cancer

www.iarc.fr/

International Programme on Chemical Safety

http://www.inchem.org/

National Institute for Occupational Health and
Safety

www.cdc.gov/niosh
Research studies, health hazard evaluations, extensive links to
occupational safety and health resources on the Internet

National Library of Medicine

www.nlm.nih.gov
Databases include PubMed and TOXLINE

National Toxicology Program

http://ntp.niehs.nih.gov/
Extensive information on chemicals, reactivity, long-term and
short-term effects

NIOSH Pocket Guide to Chemical Hazards

http://www.cdc.gov/niosh/npg/
Also gives a link to the Registry of Toxic Effects of Chemical
Substances (RTECS) database

Royal Society of Chemistry Environment
Health & Safety Committee Notes

http://www.rsc.org/
COSHH in Laboratories; Fire Safety in Chemical Laboratories

12 Spectroscopy
The regions of the electromagnetic spectrum are shown in Table12.1. The following sections deal with
infrared (IR) spectroscopy, ultraviolet (UV) spectroscopy, and nuclear magnetic resonance (NMR)
Table12.1
The Electromagnetic Spectrum
Region

Range

Vacuum ultraviolet
Ultraviolet
Visible
Near infrared
Infrared
Far infrared

100–180 nm
180–400 nm
400–750 nm
0.75–2.5 μm
2.5–15 μm
15–300 μm

12.1 Infrared Spectroscopy
12.1.1 Window Materials, Mulling Oils, and Solvents
Note: IR absorption can depend on whether mull or solvent is used
12.1.1.1 Window Materials
The transmission ranges of various window materials are listed in Table12.2.
Table12.2
Window Materials
Material
NaCl
KBr
AgCl
CaF2
CsBr
ZnS

Transmission Range (cm–1)
40 000–590
40 000–400
25 000–435
67 000–1100
10 000–270
10 000–680

12.1.1.2 Mulling Oils
Nujol® (a high-molecular-weight hydrocarbon) can be used from 650 cm–1 to the far infrared. It
gives IR absorptions around 2900 (vs), 1460, and 1350 cm–1. Fluorolube® (a high-molecular-weight
fluorinated hydrocarbon) is useful for the range 4000 to 1370 cm–1. Hexachlorobutadiene can also
be used.

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12.1.1.3 Solvents
The following solvents are commonly used to record IR spectra. They cannot be used in the regions
shown (cm–1).
• Carbon disulfide
1 mm cell: 2340–2100, 1640–1385, 875–845
0.1 mm cell: 2200–2140, 1595–1460
• Carbon tetrachloride
1 mm cell: 1610–1500, 1270–1200, 1020–960, <860
0.1 mm cell: 820–720
• Chloroform
1 mm cell: 3090–2980, 2440–2380, 1555–1410, 1290–1155, 940–910, <860
0.1 mm cell: 3020–3000, 1240–1200, <805

12.1.2 Characteristic Infrared Absorption Bands
The characteristic IR absorption bands of various types of compounds are listed in Table12.3, in
two complementary formats.

Table12.3
Characteristic IR Absorption Bands
Type of Compound

Alcohols

Bond

Type of Vibration

Frequency (cm–1)

(a) Presented alphabetically by type of compound
C−O
Stretching
1300–1050

(Not H-bonded)
(H-bonded)

C−H
O−H

Stretching
Stretching

3650–3600
3600–3200

Aldehydes

C−H
CO

Stretching
Stretching

2900–2700
1740–1690

Alkanes

C−H

Stretching

3000–2800

Alkenes

CC
C−H
C−H

Stretching
Bending
Stretching

1680–1600
995–675
3100–3000

Alkyl bromides
chlorides
fluorides
iodides

C−Br
C−Cl
C−F
C−I

Stretching
Stretching
Stretching
Stretching

680–500
850–600
1400–1000
500–200

Alkynes

C−H
C≡C

Stretching
Stretching

3350–3300
2250–2100

Amides

CO

Stretching

1715–1630

Amines

N−H
C−H
N−H

Bending
Stretching
Stretching

1650–1550
1350–1000
3500–3100

191

Spectroscopy

Table12.3 (continued)
Characteristic IR Absorption Bands
Type of Compound

Bond

Type of Vibration

Frequency (cm–1)

Aromatics

C−H
CC

Bending
Stretching

C−H

Stretching

900–680
1625–1570
1525–1475
3150–3000

Carboxylic acids

O−H
CO
C−O

Stretching
Stretching
Stretching

3400–2400
1750–1690
1300–1080

Esters

C−O
CO

Stretching
Stretching

1300–1080
1780–1730

Ethers

C−O

Stretching

1300–1080

Imines/oximes

CN

Stretching

1690–1640

Ketones

CO

Stretching

1730–1650

Nitriles
Nitro

C≡N
N–O

Stretching
Stretching

2260–2240
1550–1500

Phosphorus compounds

PO
P−O
P−H

Stretching
Stretching
Bending

1300–960
1260–855
1090–910

Thiols

S−H

Stretching

2600–2500

(b) Presented in order of decreasing frequency
Type of Compound

Bond

Type of Vibration

Frequency (cm–1)

Alcohols
Alcohols
Amines
Carboxylic acids
Alkynes
Aromatics
Alkenes
Alkanes
Aldehydes
Thiols
Nitriles
Alkynes
Esters
Carboxylic acids
Aldehydes
Ketones
Amides
Imines/oximes
Alkenes

O−H
O−H
N−H
O−H
C−H
C−H
C−H
C−H
C−H
S−H

Stretching
Stretching
Stretching
Stretching
Stretching
Stretching
Stretching
Stretching
Stretching
Stretching
Stretching
Stretching
Stretching
Stretching
Stretching
Stretching
Stretching
Stretching
Stretching

3650–3600
3600–3200
3500–3100
3400–2400
3350–3300
3150–3000
3100–3000
3000–2800
2900–2700
2600–2500
2260–2240
2250–2100
1750–1730
1750–1690
1740–1690
1730–1650*
1715–1630
1690–1640
1680–1600

C≡N
C≡C
CO
CO
CO
CO
CO
CN
CC

(continued on next page)

192

Organic Chemist's Desk Reference, Second Edition

Table12.3 (continued)
Characteristic IR Absorption Bands
Type of Compound

Bond

Type of Vibration

Frequency (cm–1)

Amines
Alkyl fluorides
Amines
Carboxylic acids
Esters
Ethers
Acohols
Phosphorus compounds
Phosphorus compounds
Phosphorus compounds
Alkenes
Aromatics
Alkyl chlorides
Alkyl bromides
Alkyl iodides

N−H
C−F
C−N
C−O
C−O
C−O
C−O

Bending
Stretching
Stretching
Stretching
Stretching
Stretching
Stretching
Stretching
Stretching
Bending
Bending
Bending
Stretching
Stretching
Stretching

1650–1550
1400–1000
1350–1000
1300–1080
1300–1080
1300–1080
1300–1050
1300–960
1260–855
1090–910
975–675
900–680
850–600
680–500
500–200

PO
P−O
P−H
C−H
C−H
C−Cl
C−Br
C−I

cyclobutanone and cyclopentanone absorb up to 1780 cm–1.

12.2 Ultraviolet Spectroscopy
12.2.1 Ultraviolet Cutoff Limits for Solvents
These cutoff limits, which are listed in Table12.4, are the wavelengths at which the absorbance
approaches 1.0 in a 10 mm cell.
Table12.4
UV Cutoff Limits for Solvents
Solvent
Acetonitrile
Water
Methanol
Cyclohexane
Hexane
Ethanol (95%)
1,4-Dioxane
Diethyl ether
Tetrahydrofuran
Dichloromethane
Chloroform
Carbon tetrachloride
Benzene
Toluene
Acetone

Wavelength (nm)
190
205
210
210
210
210
215
215
220
235
245
265
280
285
330

193

Spectroscopy

12.2.2 Characteristic Ultraviolet/Visible Absorption Bands
The characteristic UV/VIS absorption bands for some representative chromophores are listed in
Table12.5.
Table12.5
UV/VIS Absorption Bands for Representative
Chromophores
λmax (εmax)

Chromophore
Aldehydes
Amides

−CHO
−CONH2

Amines
Azides
Azo compounds
Bromides
Carboxylic acids
Chlorides
Disulfides
Esters
Ethers
Imines
Iodides
Ketones
Nitriles
Nitro compounds
Nitroso compounds
Oximes
Sulfides
Sulfones
Sulfoxides
Thiols

−NH2
−N3
−NN–
−Br
−COOH
−Cl
−S−S−
−COOR
−O−
>CN−
−I
>CO
−C≡N
−NO2
−NO
N−OH
−S−
−SO2−
−S(O)−
−SH

Unsaturated Systems
Alkenes
−CC−
Alkynes
−C≡C−
Allenes
CCC
Ketenes
CCO

180–210 (10 000), 280–300 (15)
175–180 (7000), 210–220 (60)
190–200 (3000)
287 (20)
330–400 (10)
200–210 (300)
195–210 (50)
170–175 (300)
194 (5500), 250–255 (400)
195–210 (50)
180–185 (2000)
190 (5000)
255–260 (400)
180–195 (1000), 270–290 (20)
160–165 (5)
200–210 (10 000), 275 (20)
300 (100), 600–665 (20)
190–195 (5000)
194 (4600), 210–215 (1500)
180
210–230 (1500)
190–200 (1500)

162–175 (15 000), 190–195 (10 000)
175–180 (10 000), 195 (2000), 223 (150)
170–185 (5000), 225–230 (600)
225–230 (600), 375–380 (20)a

Conjugated Systems (see Section 12.2.3 for Woodward-Fieser Rules)
210–230 (21 000)
−(CC)2−
(acyclic)
260 (35 000)
−(CC)3−
300 (52 000)
−(CC)4−
330 (118 000)
−(CC)5−
230–260 (3000–8000)
−(CC)2− (cyclic)
219–230 (7500)
−CC−C≡C−
220 (23 000)
−CC−CN−
210–250 (10 000–20 000), 300–350 (30)
−CC−CO
−CC−NO2

229–235 (9500)
(continued on next page)

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Table12.5 (continued)
UV/VIS Absorption Bands for Representative
Chromophores
λmax (εmax)

Chromophore

−CC−C≡N
−C(O)C(O)−

214 (4500), 308 (20)
206 (13 500), 242 (250)
210 (6000)
215 (680)
195 (25), 280–285 (20), 420–460 (10)

Aromatic Systems
Benzene
Biphenyl
Naphthalene
Anthracene
Pyridine
Quinoline
Isoquinoline

184 (46 700), 204 (6900), 255 (170)
246 (20 000)
222 (112 000), 275 (5600), 312 (175)
252 (199 000), 375 (7900)
174 (80 000), 195 (6000), 257 (1700)
227 (37 000), 270 (3600), 314 (2750)
218 (80 000), 266 (4000), 317 (3500)

−C≡C−CO
−CC−COOH
−C≡C−COOH

12.2.3 UV/VIS Absorption of Dienes and Polyenes
The Woodward-Fieser rules can be used to estimate the UV/VIS absorption as follows:
Parent Diene System
Acyclic

215 nm

Heteroannular

214 nm

Homoannular

253 nm

Increments
For each additional conjugated double bond
For each exocyclic double bond
For each substituent
C substituent
OAc
OR (R = alkyl)
SR (R = alkyl)
Cl, Br
NR2 (R = alkyl)
Solvent Correction

+30 nm
C

+5 nm

+5 nm
0 nm
+6 nm
+30 nm
+5 nm
+60 nm
0 nm

195

Spectroscopy

Examples

Acyclic
Four alkyl substituents

215 nm
20 nm
235 nm

Heteroannular
Four alkyl substituents
Exocyclic double bond

214 nm
20 nm
5 nm
239 nm

12.2.4 UV/VIS Absorption of α,β-Unsaturated Carbonyl Compounds
The Woodward-Fieser rules can be used to estimate the UV/VIS absorption as follows:
Parent System
δ

C
O

Acyclic α,β-unsaturated ketone
α,β-Unsaturated aldehyde
α,β-Unsaturated carboxylic acid or ester
Six-membered cyclic α,β-unsaturated ketone
Five-membered cyclic α,β-unsaturated ketone

215 nm
207 nm
193 nm
215 nm
202 nm

Increments
For each additional conjugated double bond

+30 nm
C

For each exocyclic double bond

+5 nm

For each homoannular diene system

+39 nm

For each substituent at the π-electron system (nm)

C substituent
OH
OAc
OR (R = alkyl)
SR (R = alkyl)
Cl
Br
NR2 (R = alkyl)

δ and Beyond

10
35
6
35

12
30
6
30
85
12
30
95

18
50
6
31

12
25

6
17

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Organic Chemist's Desk Reference, Second Edition
Solvent Corrections
Water
Ethanol, methanol
Chloroform
Dioxane
Diethyl ether
Hexane, cyclohexane

+8 nm
0 nm
–1 nm
–5 nm
–7 nm
–11 nm

Examples
O
β

Acyclic ketone

215 nm
10 nm
12 nm
237 nm

α-Alkyl group
β-Alkyl group

δ γ β

Six-membered cyclic ketone
Additional conjugated bond
Exocyclic bond
β-Alkyl group
γ-Alkyl group
δ-Alkyl group

215 nm
+30 nm
+5 nm
+12 nm
+18 nm
+18 nm
298 nm

12.3 Nuclear Magnetic Resonance Spectroscopy
Ross Denton
Nuclear magnetic resonance (NMR) spectroscopy is the most powerful spectroscopic method for
structural elucidation of organic molecules and is routinely used by organic chemists. Summarised
below are common NMR active nuclei; chemical shift data for NMR solvents, common impurities,
and functional groups; coupling constants; and details of common NMR experiments used to determine the connectivity and stereochemistry of small organic molecules.

12.3.1 Common Nuclei Used in NMR
These are listed in Table12.6, along with details on NMR frequency and isotopic abundance.

12.3.2 Chemical Shift Data
Table12.7 contains a summary of chemical shift data for residual protons in commonly used NMR
solvents. Table12.8 contains chemical shift data for solvents and other common impurities. The
ranges of the 1H, 13C, 19F, and 31P NMR chemical shifts of various functional groups are shown in
Figures12.1 to 12.4, respectively and in a different format in Tables 12.9 to 12.12.

197

Spectroscopy

Table12.6
Common Nuclei Used in NMR
Nucleus

Spin

NMR Frequency (Hz)
at 11.74 T

Isotopic Abundance
(%)

H
H
11B
13C

1/2
1
3/2
1/2

500.000
76.753
160.419
125.721

99.98
0.01
80.42
1.11

N
N
17O
19F
31P

1
(–)1/2
(–)5/2
1/2
1/2

36.118
50.664
67.784
470.385
202.404

99.63
0.37
0.037
100
100

1
2

14
15

Table12.7
Chemical Shift Data for Residual Protons in Common
NMR Solvents
Solvent
Acetic acid-d4
Acetone-d6
Acetonitrile-d3
Benzene-d6
Carbon disulfide
Carbon tetrachloride
Chloroform-d
Deuterium oxide
Dimethyl-d6 sulfoxide
1,4-Dioxane
Methanol-d4
Hexachloroacetone
Pyridine-d5
Toluene-d8
Trifluoroacetic acid-d
a

δ (ppm) of Residual Protons

δ 13C (ppm)

2.0, 11.5
2.0
2.0

21, 177
30, 205
0.3, 117

7.2
—
—
7.2
4.8a
2.5
3.7
3.4, 4.8a
—
7.2, 7.6, 8.5
2.4, 7.3
13.0

128
1931
97
77
—
43
67
49
124, 126
124-150
21, 125–138
115, 163

Value may vary considerably depending on the solute.

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Organic Chemist's Desk Reference, Second Edition

Table12.8
Chemical Shift Data for Common Solvents and Impurities in CDCl3
Compound

H NMR δ (ppm)

Acetic acid
Acetone
Acetonitrile
Benzene
1,2-Dichloroethane
Dichloromethane
Diethylene glycol dimethyl ether (diglyme)
Diethyl ether
N,N-Dimethylacetamide
N,N-Dimethylformamide
Dimethylsulfoxide
1,4-Dioxane
Ethanol
Ethyl acetate
Ethylene glycol
Grease
n-Hexane
Methanol
Nitromethane
2-Propanol
Pyridine
Tetrahydrofuran
Toluene
Triethylamine
o-Xylene

2.10 (s), 11.4 (s)
2.17 (s)
2.10 (s)
7.34 (s)
3.73 (s)
5.30 (s)
3.65 (m), 3.57 (m)
3.47 (q), 1.21 (t)
3.02 (s), 2.94 (s), 2.09 (s)
8.02 (s), 2.96 (s), 2.88 (s)
2.62 (s)
3.71 (s)
3.72 (q), 1.32 (s), 1.25 (t)
4.12 (q), 2.05 (s), 1.26 (t)
3.76 (s)
1.26 (m), 0.86 (broad s)
1.26 (m), 0.88 (t)
3.49 (s), 1.09 (s)
4.33 (s)
4.04 (sep), 1.22 (d)
8.62 (m), 7.68 (m), 7.29 (m)
3.76 (m), 1.85 (m)
2.36 (s), 7.17 (m), 7.25 (m)
2.53 (q), 1.03 (t)
7.07 (m), 2.22 (s)

C NMR δ (ppm)

177.0, 20.8
207.1, 30.9
116.4, 1.9
128.4
43.5
53.5
71.9, 70.5, 59.0
65.9, 15.2
171.1, 38.1, 35.3, 21.5
162.6, 36.5, 31.5
40.8
67.1
58.3, 18.4
171.4, 60.5, 21.0, 14.2
63.8
29.8
31.6, 22.7, 14.1
50.4
62.5
64.5, 25.1
149.0, 136.0, 123.8
68.0, 25.6
137.9, 129.1, 128.3, 125.3, 21.5
46.3, 11.6
136.8, 130.3, 126.5, 18.8

Note: Multiplicities are designated using the following abbreviations: s = singlet, d = doublet, t = triplet, q = quartet, sep =
septet.
See Gottlieb, H. E., et al., J. Org. Chem., 62, 7512–7515, 1997.

199

Spectroscopy

δ (ppm)
5

0
–C–CH3
–C–CH2–C–
CH3–C=C–
CH3–CO

CH3–N–

–

CH3–Ar
–C CH
–C–CH2–N–
–C–CH2Ar
=C–CH2–C–
=C–CH2–N–
–C–CH2–N–
Ar–CH2N
NH amino
CH3O
–C–CH2–O
=C–CH2–O
Ar–CH2–O
–C=CH2
HC=CH
NH amido
Ar–H
–CHO

Figure 12.1 Ranges of 1H NMR chemical shifts for various groups (Ar = aromatic ring) relative to δ
(TMS) = 0.

200

Organic Chemist's Desk Reference, Second Edition

δ (ppm)
240

200

160

120

0
CH
–– 3–C–; CH
– 3–C=X; CH
– 3–C X
–C–CH
– 2–C–
–C C–
(–C–)3–C–C–
–
CH3–O–
–C–CH
– 2–O–
(–C–)2–CH–O–
–
CH2=C
X
CH
C=C
–C N
α,β–unsat. COOH
–
–C–COOH
–
α,β–unsat. CO
–
–C–CHO
–
–C–CO–C–
–

Figure 12.2 Ranges of
δ(TMS) = 0.

C NMR chemical shifts for various groups (X = any group) relative to

201

Spectroscopy
δ (ppm)
0

–50

–100

FPOMe

FBCl2

–150

SbF5

CF2Cl2

BF3

–200

FSiH2
MoF6 at –278

Most fluorocarbons

CFBr3

PhCF3

PhF

CF3COOH

XeF6 at 550
WF6 at 166

C2H5F

CHF2CHF2

CF2=CH2

CH3F at –272

CHF=CF
2
–

CHF=CH2

Figure 12.3 Ranges of 19F NMR chemical shifts relative to δ (CFCl3) = 0. (Reproduced with permission
from W. Kemp, NMR in Chemistry, published by Macmillan Press Ltd., 1986.)

δ (ppm)
300

200

100

–100

–200

–300

–400

–500

Phosphorus(III)

PX3

RPX2

(R2N)3P

R3P

(Me3Si)3P

R2PX

Phosphorus(V)
R3PO
PCl5+

PO4–

PX5
PF6–

PCl6–

Figure 12.4 Ranges of 31P NMR chemical shifts relative to δ (H3PO4(aq.)) = 0. (Reproduced with permission from W. Kemp, NMR in Chemistry, published by Macmillan Press Ltd., 1986.)

202

Organic Chemist's Desk Reference, Second Edition

Table12.9
1H and 13C Chemical Shifts for a Methyl Group in Various Situations
H (δ ppm)

H3C

O
C

H3C

O
H3C
a

C (δ ppm)

H (δ ppm)

C (δ ppm)

0.7–1.3

8–24

H3C

2.1–2.5

30–45

1.7–2.0

15–27a

H3C

3.3–3.5

56–59

2.0–2.1

26–31

3.6–3.9

51–52

2.0–2.1

20–22

O
H3C

Dependent on stereochemistry.

Table12.10
Aromatic Substituent Effects in NMR
1

H (ppm)

Parent

C (ppm)

7.27

128
Increments

Substituent
–CH3

ortho-H

meta-H

para-H

C-1 (ipso)

ortho-C

meta-C

para-C

–0.2

–0.1

–0.2

–2

0.2

–2

–F
–Cl
–Br
–I
–OH
–OCH3
–OCOCH3
–SR
–SO3H
–NH2, –NMe2
–NO2
–CHO
–CO.R
–CO2H
–CN

–0.3
0
0.2
0.35
–0.45
–0.2
–0.2
0.1
0.4
–0.8
1.0
0.65
0.6
0.8
0.3

0
0
–0.1
–0.2
–0.1
–0.2
0
–0.1
–0.1
–0.15
0.2
0.2
0.3
0.15
0.3

–0.2
–0.1
–0.05
0
–0.2
–0.2
–0.1
–0.2
0.1
–0.4
0.4
0.4
0.3
0.2
0.3

35
6
5
–32
27
30
23
4
16
20
20
9
9
2
–15

–14
0
3
10
–13
–15
–6
1
0
–15
–5
1
0
2
4

1
1
2
3
1
1
1
1
0
1
1
1
0
0
1

–5
–2
–2
–1
–7
–8
–2
–3
4
–10
6
6
5
5
4

Note: Aromatic compounds also have distinctive UV absorptions.

203

Spectroscopy

Table12.11
Variation in 13C Chemical Shifts with Chain Length and Ring Size
Ring Size

C
(δ ppm)

3
4
5
6
7
8

–2.9
22.5
25.7
27.0
28.9
27.5

Chain Length

C (δ ppm)

CH4
CH3.CH3
CH3.CH2.CH3
CH3.CH2.CH2.CH3
CH3.CH2.CH2.CH2.CH3
CH3.CH2.CH2.CH2 …

–2.3
5.7
15
13
14
14

5.7
16
25
23
23

15
25
33
33

13
23
29.5

14
…

Note: These values change in the presence of substituents and chain branching.
44.0
34.6

38.7

24.5

27.1

36.9

30.1

36.8
29.7

norbornane

H
trans-decalin

cis-decalin

Table12.12
13C Chemical Shifts for Various Alkenes (δ ppm)
H
H2C

H
139

H 3C

CH2

115

124

CH2 21

112

144

H 2C

133

H2C

17.5

CH3

144

H 3C

CH2

110

132

25.5

C
124

H
107

25
127

150

CH2

131
49
25

133
42

136

CH3
120

H
166–170 C

124–130

80–100

150–155

30
29

133

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Organic Chemist's Desk Reference, Second Edition

12.3.3 Coupling Constants
The sign and magnitude of H–H coupling constants and CÂ�–H coupling constants are summarized
in Tables12.13 and 12.14, respectively.
Table12.13
Summary of H–H
Coupling Constants
J
J
3+nJ
2
3

JH–H (Hz)

Sign

0–30
0–18
0–7

–
+
+ or –

Table12.14
Summary of C–H
Coupling Constants
J
J
3J
3+n J
1
2

JC–H (Hz)

Sign

125–250
–10 to +20
1–10
<1

+
+ or –
+
+ or –

See the following references for more information:
Williams, D. H., and Fleming, I., Spectroscopic Methods in Organic Chemistry (New York:
McGraw-Hill, 1989).
Harwood, L. M., and Claridge, T. D. W., Introduction to Organic Spectroscopy (Oxford:
Oxford University Press, 1997).
Friebolin, H., Basic One- and Two-Dimensional NMR Spectroscopy (Weinheim Wiley-VCH,
2005).
12.3.3.1 Geminal H–H Coupling (2JH–H)
The magnitude of geminal coupling constants 2JH–H depends on the hybridisation of the carbon
atom, the H–C–H bond angle, and electronegative substituents. In general, the observed coupling
constant becomes more positive as the H–C–H bond angle increases (see Table12.15; Williams and
Fleming, Harwood and Claridge, and Friebolin, as above).
Table12.15
Common 2JH–H Coupling Constants
(R = Alkyl Group)
2

JH–H (Hz)
–4.5

H
H

+41

O
H
H
H

+3 to –3

R2
R1

JH–H (Hz)
–12.5

H
H

R2
R1O

R2O
R1O

10.5

H
–6.0

12.3.3.2 Vicinal HÂ�– H Coupling (3JH–H)
The average 3JH–H value for a “freely” rotating carbon-carbon bond is approximately 7–8 Hz. Vicinal
coupling constants are reduced (ca. less than 1 Hz) by electronegative substituents and reduced as

205

Spectroscopy

the length of the carbon-carbon bond increases (see Williams and Fleming, Harwood and Claridge,
and Friebolin, as above). Vicinal coupling constants also vary as a function of the dihedral angle
according to the Karplus equation 3JH–H = 4.22 – 0.5 cosθ + 4.5 cos2θ (where θ is the dihedral angle)
(Karplus, M., J. Am. Chem. Soc., 85, 2870–2871, 1963). Figure12.5 illustrates this relationship,
while Table12.16 contains common 3JH–H values.
10
9
8

3J
H-H

7
6

Dihedral angle

4
3
2
1
0

100

150

200

Dihedral Angle

Figure 12.5 Variation of 3JH–H as a function of the dihedral angle.

Table12.16
Common 3JH–H Coupling Constants
3

JH–H (Hz)

H
H
Freely
rotating

8–9

Cyclohexane
axial-axial
Cyclohexane
axial-equatorial

10–12

2–5

10–12

Cyclohexane
equatorial-equatorial

0–5

9–13

Cyclobutane

trans 5–9
cis 6–10

8–10
14–16

H
H

H
4–8

Cyclopropane

NH2

trans 3–6
cis 6–10

7.5

H
4–10

OH
H
H

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12.3.3.3 Long-Range Coupling Constants (3+nJH–H)
Couplings through more than three bonds are typically less than 1 Hz. An exception occurs when the
bonds are fixed in a “W” conformation. Common 3JH–H coupling constants are listed in Table12.17
(Williams and Fleming, Harwood and Claridge, and Friebolin, as above).
Table12.17
Common JH–H Coupling Constants
JH–H (Hz)
H

0–3

JH–H (Hz)
+7

H
1–2

0.8

12.3.4 Modern NMR Techniques for Structural Elucidation of Small Molecules
Modern NMR experiments are used extensively for structure elucidation. A summary of the most
important one- and two-dimensional methods for small molecules is given below. The experiments, which can be fully automated and used routinely in academic and industrial laboratories, are
subdivided into homo- and heteronuclear one-dimensional methods and homo- and heteronuclear
two-dimensional methods (see Friebolin, as above; Sanders, J. K. M., and Hunter, B. K., Modern
NMR Spectroscopy: A Guide for Chemists (Oxford: Oxford University Press, 1993)).
12.3.4.1 1D Methods
12.3.4.1.1 APT (Attached Proton Test)
An experiment for assigning multiplicities to signals in decoupled 13C spectra. The experiment
shows all carbon signals (as opposed to DEPT) with CH and CH3 appearing positive, while quaternary carbons and CH2s appear as negative peaks.
12.3.4.1.2 DEPT (Distortionless Enhancement of Polarisation Transfer)
An experiment for assigning multiplicities to signals in decoupled 13C spectra. It is more sensitive
than the APT; however, it must be run with three different final pulse angles (45, 90, and 135) and
compared to the original decoupled 13C spectrum. DEPT 45 shows CH, CH2, and CH3 as positive;
DEPT 90 shows CH as positive; DEPT 135 shows CH and CH3 as positive and CH2 negative.
12.3.4.1.3 1
D INADEQUATE (Incredible Natural Abundance
Double Quantum Transfer Experiment)
An experiment for obtaining 1JC–C values. The names are characteristic of the carbon-carbon bond
order. For example, 1JC–C = 35–45 for a C–C single bond while 1JC–C = 65 for a double bond. The
main decoupled signals are removed and the satellite peaks appear as positive and negative signals.
The experiment requires 13C-enriched or very concentrated samples.

Spectroscopy

207

12.3.4.2 2D Methods
12.3.4.2.1 1H–1H COSY (Correlated Spectroscopy)
An experiment that correlates spin-coupled protons. The spectrum contains a “diagonal,” which
contains the 1D spectrum. The correlated protons appear as cross-peaks off the diagonal; therefore,
a pair of coupled protons, whose signals appear on the diagonal, and their associated cross-peaks
form the corners of a square. A very useful experiment when overlapping signals and non-first-order
effects complicate the 1D 1H spectrum.
12.3.4.2.2 1 H–1H TCOSY (Total Correlated Spectroscopy, also known
as HOHAHA (Homonuclear Hartman Hahn))
An experiment that correlates spin-coupled protons. It differs from 1H–1H COSY in that correlations
are seen between all protons in the spin system and not just those directly coupled. Correlations
appear as cross-peaks.
13C–13C INADEQUATE (Incredible Natural Abundance
Double Quantum Transfer Experiment)
An experiment that correlates spin-coupled carbons. A very insensitive experiment that can be
made practical if the sample can be 13C enriched. At natural abundance extremely concentrated
samples and long acquisition times are required; however, direct carbon-carbon connectivity can
be obtained.

12.3.4.2.3

12.3.4.2.4 1H–1H NOESY (Nuclear Overhauser Effect Spectroscopy)
An experiment that correlates protons that are close in space. The experiment can be performed in a
1D fashion (NOE or nOe) if individual resonances are preselected. Usually used for molecules with
high molecular weights (>1,500). The diagonal contains the 1D spectrum; protons near to each other
in space are correlated as cross-peaks that appear off the diagonal.
12.3.4.2.5 1 H–1H ROESY (Rotating Overhauser Effect Spectroscopy)
An experiment that correlates protons that are close in space. The experiment can be performed in
a 1D fashion (NOE) if individual resonances are preselected. Usually used for molecules with low
molecular weights (<800). The diagonal contains the 1D spectrum; protons near to each other in
space are correlated as cross-peaks that appear off the diagonal.
12.3.4.2.6 1 H–13C HMQC (Heteronuclear Multiple Quantum Coherence)
An experiment that correlates spin-coupled protons and carbons. This experiment is selective for
one-bond couplings and therefore provides direct carbon-hydrogen connectivity. The spectrum does
not contain a diagonal; proton and carbon signals are correlated via cross-peaks.
12.3.4.2.7 1H–13C HMBC (Heteronuclear Multiple Bond Coherence)
An experiment that correlates spin-coupled protons and carbons. This experiment is selective for
two- to four-bond couplings and therefore provides long-range carbon-hydrogen connectivity. The
spectrum does not contain a diagonal; proton and carbon signals are correlated via cross-peaks.

13 Mass Spectrometry
James McCullagh

13.1 Introduction
A fundamental aspect of mass spectrometry is the formation of positive or negative ions and the
subsequent gas phase measurement of their mass to charge ratio (m/z). A ubiquitous method of ion
formation and analysis does not exist for all compounds, and hence a range of mass spectrometer
systems has been developed with different ion sources, sensitivity, resolution, mass range, mass
accuracy, and fundamental suitability for different compounds. This chapter provides information
relevant to organic chemists preparing samples for mass spectrometry analysis or analysing their
results. Since the first edition of The Organic Chemist’s Desk Reference significant growth in mass
spectrometer systems, performance, and their applications has taken place, and this section has
been extended and updated to reflect these developments.

13.2 Ionisation Techniques and Mass Spectrometer Systems
A number of different ionisation methods are used in mass spectrometry to form analyte gas phase
ions. These are generated through the transfer of an electron to or from an uncharged analyte,
protonation, de-protonation, cationisation, anionisation, or the transfer of charge from the solid to
the gas phase. Table13.1 lists a number of the more common ionisation methods used in organic
mass spectrometry, and Table13.2 provides comparative attributes, including appropriate ionisation
techniques, for several common mass spectrometer systems.

209

210

Table13.1
Common Ionisation Methods
Sample Type

Typical Analytes

Ions Formed

Electrospray
ionisation
(ESI)

Nonvolatile liquids
and solids in
solution
Gasses, volatile
liquids, and solids

(M + nH)
(M – nH)n–
(M + cation)+
(M + NH4)+
M+, M–

~High
femtomole

Electron impact
(EI)

Wide range of polar and nonvolatile
compounds sufficiently basic to accept a
protein (positive mode) or sufficiently
acidic to lose a proton (negative mode)
Hydrocarbons
Aromatics

Chemical
ionisation (CI)

Gasses, volatile
liquids, and solids

(M + H)+
(M – H)–

~Low
picomole

Matrix-assisted
laser
desorbtion
(MALDI)
Fast atom
bombardment
(FAB)
APCI

Volatile and
nonvolatile solids

Small compounds (<1,000 Da) containing
a heteroatom, for example, halogenated
aromatics, sugars, and organic acids
Synthetic and biopolymers and a wide
range of polar and nonvolatile
compounds; good for large molecules

(M + H)+
(M – H)–
(M + cation)+
M+
(M + H)+
(M – H)–

~Femtomole

Nonvolatile solids in
solution

Carbohydrates, organometallics, peptides,
nonvolatiles

Soluble, polar, and
ionic compounds

Small, soluble nonvolatile polar and ionic
compounds

Field desorbtion
(FD)

Nonpolar
compounds

High molecular mass, nonpolar
compounds; good examples: larger
organometallics

Field ionisation
(FI)

Any polar or
nonpolar compound
of low mass

Small molecules (<500 Da)

Source: Data compiled from Siuzdak, 2006; Watson and Sparkman, 2007.

Ion
Sensitivity

Advantages

Disadvantages

Amenable to a broad range of
compounds, very little fragmentation,
useful for LC/MS with nonvolatile
compounds
Fragmentation is characteristic for a
given compound providing a uniquely
identifiable mass spectrum
Soft ionisation technique; can form
pseudomolecular ions with little
fragmentation
Very little fragmentation,
predominantly singly charged species
formed; low sample volumes required

Not amenable to nonprotonatable/
de-protonable species such as
hydrocarbons

~Picomole

Mild ionisation up to ~5,000 Da

(M + H)+
(M – H)–
(M + cation)+
M+, M–, MH+

~High
femtomole

Very efficient ionisation at atmospheric
pressure; very little fragmentation

Mass range limited; ESI has now
largely replaced FAB due to
greater sensitivity and ease of use
Limited to molecular weights up
to ~1,500 Da

~Micromole

Only molecular ions are formed, no
fragmentation

M+

~Micromole

Only molecular ions are formed, no
fragmentation, easier to use than FD

~Low
picomole

High energy, leads to multiple
cleavages and rearrangements,
complex mass spectra to interpret
Still leads to fragmentation and
rearrangements
Analysis <500 Da prohibited due
to prevalence of matrix ions

Limited mass range and
sensitivity, difficult to use, slow
throughput, no automation;
largely superseded by ESI and
MALDI
Limited mass range; requires an
experienced operator

Organic Chemist's Desk Reference, Second Edition

Ionisation
Sources

211

Mass Spectrometry

Table13.2
Typical Mass Spectrometers Used for the Analysis of Organic Compounds
Compatible
Ion Sources

Accuracy
(ppm)

Resolution
(FWHM)

2–10

10,000–40,000

Unlimited

Magnetic sector

ESI, MALDI,
APCI, EI,
CI, FI
EI, ESI, FAB

3–10

30,000

10,000

Quadrupole

ESI, EI, CI,

100

4,000a

4,000

Ion trap

ESI, EI, CI,
MALDI

100

4,000a

4,000

Fourier transform
Ion cyclotron
resonance

ESI, APCI,
MALDI,
EI,CI

0.1–5

>1,500,000

~250,000

Mass Analyser
Time of flight

Source: Data compiled from Siuzdak, 2006.
a Large non-standard quadrupoles are available commercially.

Mass Range
(Da)

Typical Analysis
LC/MS, nanoelectrospray,
proteomics, small molecules and
metabolites
Isotope ratio mass spectrometry
and accelerator mass
spectrometry
Low-resolution LC/MS and GC/
MS; triple quadrupole
configuration provides MS/MS
capability
LC-MS/MS, useful for
accumulating ion when ion
signal is weak
Very high resolution, highaccuracy m/z analysis; LC/MS,
nanoLC/MS, and MALDI

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13.3 Interpreting Mass Spectra and Molecular Mass
Interpretation of mass spectra depends on the type of mass spectrometer and ionisation technique used. Hard ionisation methods such as EI produce molecular ion fragmentation, which can
be used to identify diagnostic fragmentation patterns and functional groups. Softer ionisation
techniques such as ESI and MALDI provide pseudomolecular ion formation, and rules in accordance with spectral information can be used to identify corresponding molecular structure and
elemental composition. Table13.3 lists some of the types of information that can be provided by
mass spectrometry, and Table13.4 gives definitions of molecular masses that are highly relevant
in mass spectrometry.
The molecular weight of a species has a significant effect on the number of possible molecular
formulae associated with a certain mass accuracy, and Figure13.1 demonstrates examples of this relationship for a range of mass measurement accuracies covered by current mass spectrometer systems.

Table13.3
Interpreting Mass Spectra: Types of Mass Spectrometry Experiment for Organic Chemists
Mass Spectrometry Experiment

Information Provided by Experiment

Accurate mass measurement

Accurate mass measurement of a pseudomolecular ion such as [M+nH]n+ found in a
mass spectrum can be used to determine possible molecular formulae. Accuracy of
0.5 ppm is achievable using FT-ICR-MS, and typically TOF instruments can achieve
2 ppm with appropriate calibration.
EI mass spectra provide fragmentary ions that can be used as a fingerprint to identify
species. This is suitable for small molecules (<1,000 Da), and most mass
spectrometers were used for this until the development of softer ionisation
techniques in the 1970s and 1980s.
Resolution up to 40,000 (FWHM) is achievable using TOF MS, and FT-ICR-MS can
provide resolution over 1,000,000. This is suitable for determining monoisotopic
exact mass up to four decimal places.
Nitrogen is the only element that does not have both odd or even valence and nominal
mass. Valence (+3) is odd while nominal mass (14Da) is even. Any molecule that
contains an odd number of nitrogen atoms will have an odd nominal mass. This can
be used to limit the number of potential molecular formulae.
Suitable for determining the nominal mass of a molecular ion.
Elements with distinctive isotope ratios (Cl, Br, and transition metals, for example)
will provide a distinctive isotopic cluster in the mass spectrum of a compound. This
can be used to identify the presence of elements within unknown compounds.
For a compound containing carbon atoms the peaks representing 13C [M + 1] will
register an intensity 1.1× total number of C atoms.
Purposeful fragmentation of molecular ion peaks can be used to provide structural
information. This technique has been exploited using ESI ionisation in conjunction
with LC/MS for the identification of peptide and proteins.
ESI and MALDI ion intensities represent the ease with which an analyte will
protonate or de-protonate, and hence generally cannot be used to compare
concentrations between different compounds. However, for molecules with similar
functional groups, ion intensity and concentration are often closely correlated. When
internal and external calibration can be made, quantitation using ion intensities is
possible.
Ion mobility mass spectrometry separates ions by their cross-sectional area as well as
mass. This provides the opportunity to study conformational changes to a molecule’s
structure.

Fragmentation pattern
interpretation

High-resolution mass spectra

Nitrogen rule

Low-resolution mass spectra
Isotopic abundance

Isotope peaks and number of
carbon atoms
MS/MS

Quantitation

IMS

213

Mass Spectrometry

Table13.4
Definition of Molecular Masses Relevant in Mass Spectrometry
Molecular Masses

Definitions

Example: C25H15N5O26

Calculated Mass

Average mass

Calculated using the average of the mass of
each element weighted for its natural isotopic
abundance

801.401

Nominal mass

Calculated using the mass of the most
abundant isotope of each element

Monoisotopic
mass

Calculated using the mass of the most
abundant isotope of each element

Exact mass

Calculated using the exact mass of a single
isotope of each element in the molecule

Accurate mass

Experimentally determined mass of an ion
usually used to determine the molecular
formula

C: 25 × 12.011 = 300.275
H: 15 × 1.0079 = 15.1185
N: 5 × 14.0067 = 70.0335
O: 26 × 15.999 = 415.974
C: 25 × 12 = 300
H: 15 × 1 = 15
N: 5 × 14 = 70
O: 26 × 16 = 416
C: 25 × 12.000 = 300.000
H: 15 × 1.0078 = 15.1170
N: 5 × 14.0031 = 70.0155
O: 26 × 15.994 = 415.844
C: 25 × 12.000 = 300.000
H: 15 × 1.0078 = 15.1170
N: 5 × 14.0031 = 70.0155
O: 26 × 15.994 = 415.844
Measured at 2 ppm mass
accuracy

801

800.9765

800.9740–800.9770

160
0.1 ppm
0.2 ppm
0.3 ppm
0.5 ppm
1 ppm
2 ppm
3 ppm
4 ppm
5 ppm

Number of Formulae (CHON)

140
120
100
80
60
40
20
0

100

200

300

400

500

600

700

800

900

1000

Molecular Mass (Da)

Figure 13.1 Shows the relationship between the number of molecular formulae and molecular mass for a
range of mass measurement accuracies.

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13.4 Sample Introduction and Solvent Systems
for Electrospray Mass Spectrometry
Table13.5 lists some common methods of introducing analytes for electrospray mass spectrometry,
and Table13.6 lists compatible electrospray solvent systems for organic compounds.
Table13.5
Common Sample Introduction Methods using Electrospray Ionisation
MS Sample Inlet
Direct infusion (ESI)
Nanoelectrospray
Nanomate direct infusion
LC/MS
Capillary LC/MS
nanoLC/MS

Typical Flow Rates/
Quantity Used (μl/min)
3–10
0.01–0.1
0.05–0.5
200–1,000
1–100
0.2–100

Suitable Compounds
Nonvolatile solutions where sample is not limited
Single analysis of nonvolatile solutions where sample is limited
Multiple analysis of nonvolatile solutions where sample is limited
Separation of mixtures in solution
Nonvolatile solids and liquids
Nonvolatile solids and liquids

215

Mass Spectrometry

Table13.6
Solvent Compatibility with Electrospray Ionisation
Common Solvents and
Modifiers for ESI-MS

Suitability

Water

√

Methanol
Acetonitrile
Dichloromethane
Tetrahydrofuran

√
√
√
√

Nitromethane
Ethanol, propanol, butanol
Acetone
Pyridine
Acetic acid
Volatile salts, e.g., ammonium
acetate
Volatile buffers, e.g., ammonium
bicarbonate
Trifluoroacetic acid (TFA)

√
√
√
√
√
√

DMSO
DMF
Benzene
Toluene
Carbon tetrachloride
Hexane
Involatile salts
Involatile buffers e.g., potassium
chloride
Detergents
Sodium Dodecyl Sulfate (SDS)
EDTA

Comments
Water and organic solvent mixture is the default
electrospray solvent system

If mixed with methanol
For air or protic sensitive samples use freshly distilled
nitromethane

√
Suitable in small quantities

Suitable in small quantities
Suitable in small quantities
X
X
X
X
X
X
X
X
X

Suppresses ion signal, particularly in negative ion
mode; can be difficult to flush from the instrument,
causing problems with negative ionisation.
High viscosity and interaction with PEEK tubing
Difficult to maintain a stable ion signal

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13.5 Common Adducts and Contaminants in Mass Spectra
Tables13.7 and 13.8 provide examples of common adduct and contaminant ions found in positive
and negative ionisation modes.

Table13.7
Common Positive and Negative Molecular Ion Adducts
Positive Ion Mode
[M + 23] (Na )
[M + 32]+ (MeOH)
[M + 39]+ (K+)
[M + 41]+ (CH3CN+)
[M + 59]+ (CH3CN + NH4)+
+

Negative Ion Mode
[M+45]– (Formate)
[M+59]– (Acetate)
[M+58]– (NaCl)
[M+78]– (DMSO)
[M+113]– (TFA)
[M+35.5]– (chloride)

Source: Data compiled from Keller et al., 2008.

217

Mass Spectrometry

Table13.8
Common Contaminants
m/z

Ion

Compound

[M + H]+

Methanol

[M + H]+

Acetonitrile

[M + NH4]+

Acetonitrile

[M + Na]+

Acetonitrile

[2M + H]+

Methanol

[M + H]+

Polypropylene glycol

[M + H]+

DMSO

[2M + H]+

Acetonitrile

[M + H]+

d6-DMSO

[M + H]+

Acetonitrile/formic acid

101

[M + Na]+

DMSO

102

[M + H]+

Triethylamine (TEA)

104/106

[M + Cu]+

Acetonitrile

105

[2M + Na]+

Acetonitrile

120

[M + Na + CH3CN]+

DMSO

122

[M + H]+

Tris buffer

123

[M + H]+

Dimethylaminopyridine

130

[M + H]+

Diisopropylethylamine

144

[M + H]+

Tripropylamine (TPA)

145/147

[2M + Cu]+

Acetonitrile

146

[3M + Na]+

Acetonitrile

150

[M + H]+

Phenyldiethylamine

153

[M + H]+

1,8-Diazabicyclo[5.4.0]undec-7-ene

157

[2M + H]+

DMSO

169

[2M + H]+

d6-DMSO

179

[2M + Na]+

DMSO

183

[M + H]+

Diphenylketone

186

[M + H]+

Tributylamine

225

[M + H]+

Dicyclohexyl urea (DCU)

239/241

[(M.HCl)2 – Cl]+

Triethamine

242

M+

Tetrabutylammonium

243

M+

Trityl cation

257

[3M + H]+

DMSO

273

M+

Monomethoxytrityl

279

[M + H]+

Dibutyl phthalate (plasticiser)

301

[M + Na]+

Dibutyl phthalate (plasticiser)

317

[M + K]+

Dibutyl phthalate (plasticiser)

338

[M + H]+

Erucamide

391

[M + H]+

Diisooctyl phthalate (plasticiser)

413

[M + Na]+

Diisooctyl phthalate (plasticiser)

429

[M + K]+

Diisooctyl phthalate (plasticiser)

449

[2M + H]+

Dicyclohexyl urea (DCU)

454

[M + Na + CH3CN]+

Diisooctyl phthalate (plasticiser)

798

[2M + NH4]+

Diisooctyl phthalate (plasticiser)

803

[2M + Na]+

Diisooctyl phthalate (plasticiser)

Source:

Data compiled from author’s experience and Keller, B. O., Sui, J., Young, A. B., and Whittal, R. M., “Interferences
and Contaminants Encountered in Modern Mass Spectrometry,” Anal. Chim. Acta, 627, 71–81, 2008.

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Organic Chemist's Desk Reference, Second Edition

13.6 MALDI Matrices
Table13.9 provides details of suitable matrices for a range of common MALDI analytes and appropriate solvent systems.

Table13.9
Common Matrices for MALDI
Common Sample
Substrates

Common MALDI Matrices

Peptides
Polymers
Intact bacteria

CHCA
(α-cyano-4-hydroxy cinnamic
acid)

Proteins
Peptides
Polymers

Sinapinic acid
(3,5-dimethoxy-4hydroxycinnamic acid)

m/z
[M + H]+ Suitable Solvent

Structure

189.04

Methanol
Tetrahydrofuran
Acetone

COOH

224.07

Methanol
Tetrahydrofuran
Acetone
Ethanol/water

244.08

Tetrahydrofuran
Acetonitrile/methanol

226.06

Tetrahydrofuran
Carbontetrachloride
HFIP

154.03

Methanol
Acetonitrile
Water

187.06

Acetone

186.16

Acetonitrile
Ethanol
Water

COOH
CN

HO
MeO
HO
OMe

Polar and nonpolar
synthetic polymers
Oligonucleotides
Proteins

HABA
(2-(4-Hydroxyphenylazo)
benzoic acid)

Resins
Unsaturated
aromatic polyesters

Dithranol
(1,8-Dihydroxy-9(10H)anthracenone)

Peptides
Carbohydrates
Glycolipids
Glycopeptides
Polymers

DHB (2,5-dihydroxybenzoic
acid)

Polymethyl
methacrylates

IAA
(β-indole acrylic acid)

COOH
N

COOH
OH
HO
COOH

N
H
Oligonucleotides
Nucleic acids
Carbohydrates
Peptides

THAP
(2,4,6-Trihydroxyacetophenone)

O
HO

219

Mass Spectrometry

13.7 Fragmentation Ions and Neutral Losses
Hard ionisation techniques commonly fragment molecular ions, leading to the loss of neutral species and the formation of fragmentation ions. Some common species lost in mass spectra, and
possible chemical inferences that can be drawn from this information, are shown in Table13.10. In
contrast, examples of common fragment ions that are formed are listed in Table13.11.

Table13.10
Some Common Fragments Lost in Mass Spectra
Ions

Groups

Possible Inference

Ions

Groups

Possible Inference

M–1
M–2

H
H2

Labile H, aldehydes

M – 34
M – 35, 37

H2S
Cl

Thiol
Labile chloride

M – 15
M – 16
M – 16

CH3
O
NH2

Nitro compound, sulfoxide
Sulfonamide, carboxamide

M – 41
M – 42
M – 42

C3H5
CH2CO
C3H6

Acid, oxime

M – 43

C3H7

M – 43
M – 44
M – 44
M – 45
M – 45
M – 46
M – 46
M – 48

CH2CO
CO2
C3H8
COOH
OC2H5
C2H5OH
NO2
SO

Propyl ester
Methyl ketone, aryl acetate
Butyl or isobutyl ketone, aryl
propyl ether
Propyl ketone, ArCH2CH2CH3
Methyl ketone
Ester, anhydride
Carboxylic acid
Ethyl ester
Ethyl ester
Aromatic nitro compound
Aromatic sulfoxide

M – 55

C4H7

Butyl ester

M – 56

C4H8

M – 57

C4H9

ArR (R = butyl, 2-methyl-propyl,
pentyl, 3-methyl-butyl, pentyl
ketone)
Butyl ketone

M – 57
M – 58
M – 60
M – 79, 81
M – 127

C2H5CO
C4H10
CH3COOH
Br
I

M – 17

M – 17
M – 18
M – 19
M – 20

NH3
H2O
F
HF

M – 26
M – 26
M – 27
M – 28
M – 28

C2H2
CN
HCN
CO
C2H4

M – 29

CHO

M – 29

C2H5

M – 30

C2H6
CH2O
NO
OCH3
CH3OH
S
H2O + CH3
HS

M – 30
M – 30
M – 31
M – 32
M – 32
M – 33
M – 33

Alcohol, aldehyde, ketone
Fluoride
Fluoride
Aromatic hydrocarbon
Aliphatic nitrile
Nitrile, nitrogen heterocycle
Quinone, phenol
Aromatic ethyl ether, propyl
ketone
Ketone

Ethyl ketone, ArCH2CH2CH3,
ethyl ester
Aryl methyl ether
Aromatic nitro compound
Methyl ester
Methyl ester
Sulfide, aromatic thiol
Thiol

Source: Data compiled from Wieser, 2006.

Ethyl ketone
Acetate
Bromide
Iodide

220

Organic Chemist's Desk Reference, Second Edition

Table13.11
Common Fragment Ions in Mass Spectra
m/e

Ion

CH3+

18
26
27
28
28
28
29
29

H2O+
C2H2+
C2H3+
CO+
C2H4+
N2+
CHO+
C2H5+

30
31
35, 37
36, 38
39
40
41
42
42
43
43
44
44
44
44
44
45
45
47
49, 51
50

H2CNH2+
H2OOH+
Cl+
HCl+
C3H3+
C3H4+
C3H5+
C2H2O+
C3H6+
H3CCO+
C3H7+
C2H6N+

51
55
56
57
57
58
58
59
59
59
59
60
61
61
66
68

C4H3+
C4H7+
C4H8+
C4H9+
H3CCH2CO+

OCNH2+
CO2+
C3H8+
H2CCH(OH)+
H2COCH3+
H3CCHOH+
H2CSH+
H2CCl+
C4H2+

H2CC(OH)CH3+
Me2NCH2+
COOMe+
H2CC(OH)NH2+
H2COC2H5+
C2H5CHOH+
H2CC(OH)OH+
H3CCO(OH2)+
HSCH2CH2+
H2S2+
N≡CCH2CH2CH2+

Possible Inference

Carbonyl compound
Ethyl compound
Azo compound
Aldehyde
Ethyl compound
Primary amine
Primary alcohol
Chloro compound
Chloro compound

Acetate
H3CCOX
C3H7X
Aliphatic amine
Primary amine

Aldehyde
Ether, alcohol
Ether, alcohol
Aliphatic thiol
Chloromethyl compound
Aromatic compound
C6H5X
Unsaturated hydrocarbon
C6H9X
Ethyl ketone, propionate ester
Methyl ketone, dialkyl ketone
Aliphatic amine
Methyl ester
Primary amide
Ether
C2H5CH(OH)X
Carboxylic acid
Acetate ester
Aliphatic thiol
Dialkyl disulfide
RX (R = pyrrolyl)

221

Mass Spectrometry

Table13.11 (continued)
Common Fragment Ions in Mass Spectra
m/e

Ion

CF3+

69
70
71
71
72
72
73

C5H9+
C5H10+
C5H11+
C3H7CO+

73
73
74
75
75
76
77
78
78
79
79, 81
80, 82
80
81
83, 85, 87
85
85
85
85
86
86
87

COOEt+
Me3Si+

91
91, 93
92
92
93, 95
94
94
95
97
105
105
107
107, 109
111

H2CC(OH)C2H5+
C3H7CHNH2+
C4H9O+

H2CC(OH)OCH3+
Me2SiOH+
C2H5CO(OH2)+
C6H4+
C6H5+
C6H6+
C5H4N+
C6H7+
Br+
HBr+
C5H6N+
C5H5O+
HCCl2+
C6H13+
C4H9CO+
C5H9O+
C4H5O2+
C4H9CHNH2+
H2CC(OH)C3H7+
H2CCHC(OH)
OMe+
C7H7+
C4H8Cl+
C7H8+
C6H6N+
BrCH2+
C6H6O+
C5H4NO+
C5H3O2+
C5H5S+
C6H5CO+
C8H9+
C7H7O+
C2H4Br+
C5H3OS+

Possible Inference

C5H11X
Propyl ketone, butyrate ester
Ethyl alkyl ketone
Amine
Ethyl ester
Me3SiX
Methyl ester
Me3SiOX
Propionate ester
C6H5X, XC6H4Y
C6H5X
C6H5+
RX (X = pyridinyl)
C6H5X
Bromo compound
Bromo compound
RCH2X (R = pyrrolyl)
RCH2X (R = pyranyl)
HCCl3
C6H13X
C4H9COX
RX (X = 2-pyranyl)
RX (R = 5-oxo-2-furanyl)
Amine
Propyl alkyl ketone
XCH2CH2COOMe
C6H5CH2X, H3CC6H4X
RCl (R = n-alkyl ≥ hexyl)
C6H5CH2R (R = alkyl)
RCH2X (R = pyridinyl)
BrCH2X
C6H5OR (R = alkyl)
RCOX (R = pyrrolyl)
RCOX (R = pyranyl)
RCH2X (R = thienyl)
C6H5COX
H3CC6H4CH2X
HOC6H4CH2X
RCOX (R = thienyl)
(continued on next page)

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Organic Chemist's Desk Reference, Second Edition

Table13.11 (continued)
Common Fragment Ions in Mass Spectra
m/e

Ion

Possible Inference

121

C8H9O+

123
127
128
135, 137
141

C6H5COOH2+
I+
HHI+
C4H8Br+
CH2I+

MeOC6H4CH2X
Alkyl benzoate

RBr (R = n-alkyl ≥ hexyl)

13.8 Natural Abundance and Isotopic Masses of Selected
Isotopes and Nuclear Particles
The mass difference a single electron makes is observable using high-accuracy mass spectrometry.
Table13.12 lists the atomic weight of a proton, neutron, and electron. Table13.13 lists selected isotopes along with their atomic number, atomic weight, monoisotopic mass, and relative abundance.

Table13.12
Atomic Weight of Nuclear Particles
Symbol
H
n
e

Name
Proton
Neutron
Electron

Weight (amu)
1.0073
1.0087
0.0006

223

Mass Spectrometry

Table13.13
Natural Abundance and Isotopic Masses of Selected Isotopes
Element

Isotope

Atomic No.
(Z)

Atomic Weight of
Element (Ar)

Monoisotopic Mass
12C=12.000

1.00794(7)

Natural
Abundance (%)

Hydrogen

1.0078250

99.9885(70)

Deuterium

2.0141018

0.0115(70)

Tritrium

3.0160293

0.000137(3)

Helium

Beryllium

Boron

Lithium

92.41(4)

9.0121821

100

98.93(8)

13.003354

1.07(8)

14.003241

1 × 10–14

14.003074

99.632(7)

O
O
F

Fluorine

Neon

12.0107(8)

14.0067(2)

15.000108

0.368(7)

15.994914

99.757(16)

16.999131

0.038(1)

17.999160

15.9994(3)

18.9984032(5)

18.998403

20.1797(6)

0.205(14)
100

19.992440

90.48(3)

20.993846

0.27(1)

21.991385

22.989770(2)

22.989770

24.3050(6)

23.985041

78.99(4)

24.985837

10.00(1)

25.982593

26.981538(2)

26.981358

28.0855(3)

27.976926

92.2297(7)

28.976494

4.6832(5)

29.973770

30.973761(2)

30.973761

32.065(5)

31.972.070

94.93(31)

32.971458

0.76(2)

33.967866

4.29(28)

35.967080

0.02(1)

34.968852

75.78(4)

36.965902

24.22(4)

21
22

Sodium

Magnesium

24
25
26

Aluminium

Silicon

28
29
30

Phosphorus

Sulfur

32
33
34
36
35
37
79
81

Iodine

7.59(4)

7.0160040

80.1(7)

Bromine

6.0151223

12.000000

Chlorine

99.999863(3)

19.9(7)

Oxygen

9.01212(3)
10.811(7)

0.00137(3)

4.0026032

11.009305

Nitrogen

6.941(2)

3.0160293

10.012937

Carbon

4.002602(2)

127

35.453(2)
79.904(1)
126.90447(3)

9.25(3)
100

11.01(3)
100

3.0872(5)
100

78.918337

50.69(7)

80.916291

49.31(7)

126.904468(4)

100

Source: Data compiled from Wieser, M. E., “Atomic Weights of the Elements 2005,” IUPAC Technical Report,
Pure Appl. Chem., 78, 2051–2066, 2006.
Note: The number in parentheses indicates the uncertainty in the last digit of the atomic weight. Monoisotopic mass
(relative atomic mass) refers here to the mass of a specific nuclide (isotope). Atomic weight from a specified
source is the ratio of the average mass per atom of the element to 1/12 of the mass of an atom of 12C.

224

Organic Chemist's Desk Reference, Second Edition

13.9 Glossary of Abbreviations and Terms Commonly Used
in Mass Spectrometry
Amu
APCI
CI
Da
EI
ESI
FAB
FD
FI
FT-ICR-MS
FWHM
GC-C-IRMS
GC-MS
ICP-MS
ICR
IMS
IRMPD
IRMS
LC-MS
LDMS
LOD
LOQ
M+
[M + H]+
[M – H]–
MALDI
MS/MS
m/z
QTOF
SIM
SIMS
SRM
TIMS
TOF

Atomic mass unit
Atmospheric pressure chemical ionisation
Chemical ionisation
Dalton
Electron impact ionisation
Electrospray ionisation
Fast atom bombardment
Field desorption
Field ionisation
Fourier transform ion cyclotron resonance mass spectrometry
Full width at half maximum
Gas chromatography combustion isotope ratio mass spectrometry
Gas chromatography mass spectrometry
Inductively coupled plasma mass spectrometry
Ion cyclotron resonance
Ion mobility mass spectrometry
Infrared multiphoton dissociation
Isotope ratio mass spectrometry
Liquid chromatography mass spectrometry
Laser desorption mass spectrometry
Limit of detection
Limit of quantification
Singly charged ion
Protonated pseudomolecular ion
De-protonated pseudomolecular ion
Matrix-assisted laser desorption ionisation
Mass spectrometry–mass spectrometry (tandem MS)
Mass to charge ratio of an ion
Quadrupole time of flight mass spectrometry
Selected ion monitoring
Secondary ion mass spectrometry
Selected reaction monitoring
Thermal ionisation mass spectrometry
Time of flight mass spectrometry

References
Keller, B.O., Sui, J., Young, A.B., Whittal, R.M. 2008. Interferences and contaminants encountered in modern
mass spectrometry. Analytica Chimica Acta 627: 71–81.
Siuzdak, G. 2006. The Expanding Role of Mass Spectrometry in Biotechnology. 2nd edition. San Diego: MCC
Press.
Watson, T.J. and Sparkman, D.O. 2007. Introduction to Mass Spectrometry. 4th edition. Chichester: Wiley.
Wieser, M.E. 2006. Atomic Weights of the Elements 2005 (IUPAC Technical Report). Pure Appl. Chem. 78:
2051–66.

14 Crystallography
Maureen Julian

14.1 Introduction
Crystallography is the study of molecular and crystalline structures and their properties. The unit
cell is the building block of the crystal. Once the unit cell has been measured and the fractional
coordinates are known, then bond distances and angles can be calculated. By varying the temperature of the crystal, the coefficients of thermal expansion can be calculated from the change in
the lattice parameters. By varying the pressure, the bulk modulus can also be calculated. Crystals
exhibit symmetry such as rotation axes and glides and can be classified into 32 point groups and 230
space groups. The International Tables for Crystallography are the standard guide for the literature
in crystallography. Volume A is devoted to the space group symmetries. Associated with every
direct lattice is a reciprocal lattice. The planes of the direct lattice correspond to the points of the
reciprocal lattice. Mathematical applications of the reciprocal lattice give straightforward calculations of the Bragg d-spacings and the interfacial angles of the crystal. X-rays were discovered in
1895, and x-ray diffraction is the main technique for studying molecular and crystal structures. The
scattering and interference due to the individual atoms located within the unit cell contribute to the
variation in intensity of the individual diffracted reflections. The structure factors are proportional
to the coefficients in the Fourier series that are used to calculate an electron density map.

14.2 Definitions
Ångström (Å): A unit of length used in x-ray crystallography and spectroscopy, 1Å = 10 –10 m =
0.1 nm = 10 –8 cm.
Asymmetric unit: Smallest part of the unit cell that, when operated on by the symmetry operations, produces the whole unit cell.
Basis vectors: Linearly independent vectors a, b, and c that generate the lattice.
Bragg’s law: nλ = 2 dhkl sin θhkl, where n is an integer, which is the order of the diffracted beam, λ
is the wavelength of the incoming beam, dhkl is the d-spacing, and θhkl is the Bragg angle
for the (hkl) planes.
Bravais lattice: Classification of fourteen three-dimensional lattices based on primitive and
nonprimitive unit cells. Named after Auguste Bravais, who first used them.
Bulk modulus, K: The reciprocal of the volumetric compressibility.
Crystal: A solid composed of atoms arranged in a periodic array.
Crystal systems: A classification of point groups as triclinic, monoclinic, orthorhombic, trigonal,
tetragonal, hexagonal, or cubic as determined by symmetries.
Crystallographic direction: Vector between two lattice points where the direction is indicated by
[u v w], where u, v, and w do not contain a common integer. The integers u, v, and w are
called the indices of the crystallographic direction and specify an infinite set of parallel
vectors.
Fourier series: Representation of a continuous periodic function expressed as a sum of a series of
sine or cosine terms. It is useful for the calculation of electron density.
Fractional coordinates: Coordinates of the atoms written as fractions of the basis vectors.
225

226

Organic Chemist's Desk Reference, Second Edition

Friedel’s law:
In diffraction patterns, the intensity of the hkl reflection is equal to the intensity of
– – –
the h k l reflection. Therefore, all x-ray diffraction spectra have an inversion point.
Glide: Operation that is a product of a mirror and a translation that is a fraction of the lattice vector in the plane of the mirror. There are axial glides, double glides, diagonal glides, and
diamond glides.
Interfacial crystal angle: The angle between the two normals to the crystal planes or crystal faces.
Lattice: (1) An array of points in a crystal with identical neighbourhoods. (2) An array defined by
vector t = ua + vb + wc, where u, v, w are integers and a, b, c are basis vectors.
Lattice parameters: The scalar values a, b, c, α, β, and γ. Also called lattice constants.
Miller indices, hkl: Three relatively prime integers, hkl, that are reciprocals of the fractional intercepts that the crystallographic plane makes with the crystallographic axes. The crystallo
graphic plane (hkl) is described by its Miller indices.
Point group: A group whose symmetry operations leave at least one point unmoved.
Reciprocal lattice: Array defined by vectors H(hkl) = ha* + kb* + lc*, where a*, b*, c* are basis
vectors for the reciprocal lattice and h, k, l, are integers between –∞ and +∞.
Reciprocal lattice basis vectors: Given the basis vectors a, b, c in direct space, the reciprocal lattice basis vectors a*, b*, c* are defined by the equation
 a * ⋅a

 b * ⋅a

 c * ⋅a

a * ⋅b
b * ⋅b
c * ⋅b

a * ⋅c  1
 
b * ⋅c  = 0
 
c * ⋅c  0

0
1
0

0

0

1

Space group: Symmetry group of a regularly repeating infinite pattern. Each group has an infinite
set of translations. There are 230 space groups.
Unit cell: Parallelepiped defined by basis vectors a, b, and c. Unit cell fills space under translation.

14.3 Crystallographic Point Groups
The periodicity of a lattice limits the number of compatible rotation operations to onefold, twofold,
threefold, fourfold, and sixfold. This, in turn, limits the number of point groups to thirty-two. Point
groups are used to describe individual molecules. Table14.1 shows the thirty-two point groups in
both the Hermann-Mauguin notation and the Schoenflies notation divided into seven crystal systems: triclinic, monoclinic, orthorhombic, tetragonal, trigonal, hexagonal, and cubic.
Table14.1
Crystal Systems and Their Point Groups
Crystal System

Point Groups (Hermann-Mauguin)

Triclinic
Monoclinic
Orthorhombic
Tetragonal
Trigonal
Hexagonal
Cubic

1, 1
2, m, 2/m
222, mm2, mmm
–
–
4, 4, 4/m, 422, 4mm, 42m, 4/mmm
–
–
3, 3, 32, 3m, 3m
–
–
6, 6, 6/m, 622, 6mm, 6m2, 6/mmm
–
–
–
23, m3, 432, 43m, m3m

–

Point Groups (Schoenflies)
C1, Ci
C2, Cs, C2h
D2, C2v, D2h
C4, S4, C4h , D4, C4v , D2d , D4h
C3, C3i , D3, C3v , D3d
C6, C3h , C6h , D6, C6v , D3h , D6h
T, Th, O, Td , Oh

Source: From Julian, M. M., Foundations of Crystallography with Computer Applications
(Boca Raton, FL: CRC Press, 2008), p. 114.

227

Crystallography
230 Space Groups
32 Point Groups

7 Crystal Systems
Triclinic, monoclinic,
orthorhombic, tetragonal,
hexagonal, trigonal, cubic

14 Bravais Lattices

7 Lattice Systems
Triclinic, monoclinic,
orthorhombic,
tetragonal, hexagonal,
rhombohedral, cubic

6 Crystal Families
Triclinic, monoclinic,
orthorhombic,
tetragonal, hexagonal,
cubic

Figure 14.1 Classification of space groups. (From Julian, M. M., Foundations of Crystallography with
Computer Applications (Boca Raton, FL: CRC Press, 2008), p. 174.

14.4 Space Groups
The usage of the terms triclinic, monoclinic, orthorhombic, tetragonal, and cubic is consistent for
crystal systems, Bravais lattices, and crystal families. Unfortunately, the word hexagonal takes on
three different meanings, depending on whether it is applied to crystal systems, Bravais lattices, or
crystal families. The word hexagonal is found throughout the crystallographic literature and caution must be used in interpreting it (Figure14.1).

14.5 Reciprocal Lattice
Use of the reciprocal lattice unites and simplifies crystallographic calculations. The motivation for
the reciprocal lattice is that the x-ray pattern can be interpreted as the reciprocal lattice with the
x-ray diffraction intensities superimposed on it. See Section 14.2 for the definition of the reciprocal
lattice vectors a*, b*, and c* in terms of the direct basis vectors a, b, and c. Table14.2 shows the
parallel between the properties of the direct lattice and the reciprocal lattice, and Table14.3 relates
the direct and reciprocal lattices.

14.6 Examples of Organic Crystals
Examples are shown in Table14.4.

14.7 CIF Data Format
The Crystallographic Interchange File (CIF) format is used for distributing crystallographic information. It is an open-access system of distribution of information where no charge is made to the
reader. See Acta Crystallographica Section E: Structure Reports Online, http://journals.iucr.org/e/.
This journal contains structural information including the CIF file.

228

Organic Chemist's Desk Reference, Second Edition

Table14.2
Properties of a Direct Lattice in Parallel with Those of its Reciprocal Lattice
Direct Lattice

Reciprocal Lattice

Direct lattice vector:

Reciprocal lattice vector:

t(uvw) = ua + vb + wc

H(hkl) = ha* + kb* + lc*

where a, b, c are basis vectors for the direct lattice, and u, v,
w are integers between –∞ and +∞ (including zero)

where a*, b*, c* are basis vectors for the reciprocal lattice,
and h, k, l are integers between –∞ and +∞ (including
zero)

G, the metric matrix, for the direct lattice is

G*, the metric matrix, for the reciprocal lattice is

 a ⋅ a

G =  b ⋅ a

 c ⋅ a

a ⋅b
b⋅b
c⋅b

a ⋅ c 

b ⋅ c

c ⋅ c 

Volume, V, of a unit cell in direct space is

V = det(G)

 a * ⋅a *

G* =  b * ⋅a *

 c * ⋅a *

a * ⋅b *
b * ⋅b *
c * ⋅b *

a * ⋅c * 

b * ⋅c *

c * ⋅c * 

Volume, V*, of a unit cell in reciprocal space is

V* = det(G*)

where det(G) is the determinant of G

where det(G*) is the determinant of G*

The dot product of two vectors in direct space is

The dot product of two vectors in reciprocal space is∑

t(u1 v1 w1)·t(u2 v2 w2) =

H(h1 k1 l1)·H(h2 k2 l2) =

 u2 
 
(u1 v1 w1 ) G  v2 
 
 w2 

 h2 
 

(h1 k1 l1 ) G *  k2 
 
 l2 

The magnitude squared of a vector in direct space is

 u 
 
2
t (u v w) = (u v w) G  v 
 
 w
The cos θ of the angle between two vectors in direct space
is

 u2 
 

(u1v1w1 ) G  v2 
 
 w2 
cosθ =
t1t2
where t1 and t2 are the magnitudes of the vectors t(u1 v1 w1)
and t(u2 v2 w2), respectively

The magnitude squared of a vector in reciprocal space is

 h
 
H 2 (h k l ) = (h k l ) G *  k 
 
 l 
The cos θ of the angle between two vectors in reciprocal
space is

 h2 
 
(h1 k1l1 ) G *  k2 
 
 l2 
cos θ* =
H1 H 2
where H1 and H2 are the magnitudes of the vectors H(h1 k1
l1) and H(h2 k2 l2), respectively

Source: From Julian, M. M., Foundations of Crystallography with Computer Applications (Boca Raton, FL: CRC Press,
2008), p. 215.

229

Crystallography

Table14.3
Relationship between the Direct and Reciprocal Lattices
a=

b *× c *
V*

a* =

b×c
V

c *× a *
V*

b* =

c ×a
V

a *× b *
V*

c* =

a×b
V

Table14.4
Examples of Crystallographic Data for a Few Organic Compounds
Name
Anthracene,a C14H10
Urea,a CO(NH2)2
Caffeine,a C8H10N4O3
Benzene,a C6H6
Hexamethylbenzene,b
C12H18
Muscle fatty acid
binding proteinc
a
b

Crystal
System

Point
Group

Space
Group

a, Å

b, Å

c, Å

α, °

β, °

γ, °

Monoclinic
Tetragonal
Monoclinic
Orthorhombic
Triclinic

2/m
42m
2/m
mmm
1

P21/a
P421m
P21/a
Pbca
P1

8.559
5.576
14.8
7.460
5.2360

6.014
5.576
16.7
9.66
6.1845

11.171
4.692
3.97
7.034
7.9520

90
90
90
90
103.816

124.58
90
95.81
90
98.460

90
90
90
90
100.057

Orthorhombic

222

P212121

35.4

56.7

72.7

ICDD, Powder Diffraction File, ed. W. F. McClune (Newton Square, PA: International Centre for Diffraction Data, 2000).
CIF from library of crystal files in Centre for Innovation & Enterprise, CrystalMaker Software Limited (Oxford: Oxford
University, 2006). See example in Section 14.7.
Giacovazzo, C., Monaco, H. L., Artioli, G., Viterbo, D., Ferraris, G., Gilli, G., Zanotti, G., and Catti, M., Fundamentals of
Crystallography, 2nd ed., ed. C. Giacovazzo (Oxford: Oxford University Press, 2002), p. 697.

A CIF file is given below2 for hexamethylbenzene. Information includes chemical formula, formula weight, lattice constants, volume of unit cell, information from the International Tables for
Crystallography, fractional coordinates of the individual atoms, and thermal parameters.3
_chemical_formula_sum
‘C12 H18’
_chemical_formula_weight 162.274
_cell_length_a 5.2360
_cell_length_b 6.1845
_cell_length_c 7.9520
_cell_angle_alpha 103.816
_cell_angle_beta 98.460
_cell_angle_gamma 100.057
_cell_volume 241.4
_symmetry_int_tables_number 2
_symmetry_space_group_name_H-M
‘P -1’
_symmetry_space_group_name_Hall ‘-P_1’
loop_

230

Organic Chemist's Desk Reference, Second Edition

_atom_type_symbol
_atom_type_oxidation_number
_atom_type_radius_bond
C
?
1.200
H
?
1.200
loop_
_atom_site_label
_atom_site_type_symbol
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_occupancy
_atom_site_symmetry_multiplicity
_atom_site_Wyckoff_symbol
_atom_site_attached_hydrogens
_atom_site_calc_flag
_atom_site_thermal_displace_type
_atom_site_u_iso_or_equiv
C1 C -0.5659 -0.6165 0.3192 ? 2 i ? d Uiso 0.00670
C2 C -0.6790 -0.4306 0.3870 ? 2 i ? d Uiso 0.01400
C3 C -0.6131 -0.3167 0.5689 ? 2 i ? d Uiso 0.02160
C11 C -0.6485 -0.7475 0.1238 ? 2 i ? d Uiso 0.00870
C21 C -0.8704 -0.3491 0.2613 ? 2 i ? d Uiso 0.01830
C31 C -0.7526 -0.1236 0.6369 ? 2 i ? d Uiso 0.02960
H11A H -0.5128 -0.6816 0.0588 ? 2 i ? d Uiso 0.03800
H11B H -0.8232 -0.6994 0.0685 ? 2 i ? d Uiso 0.08940
H11C H -0.6745 -0.9230 0.1142 ? 2 i ? d Uiso 0.06450
H21A H -0.8658 -0.1752 0.3195 ? 2 i ? d Uiso 0.10270
H21B H -1.0648 -0.4342 0.2551 ? 2 i ? d Uiso 0.05150
H21C H -0.8067 -0.3714 0.1419 ? 2 i ? d Uiso 0.06000
H31A H -0.9516 -0.1777 0.5787 ? 2 i ? d Uiso 0.06080
H31B H -0.6463 0.0283 0.6208 ? 2 i ? d Uiso 0.03480
H31C H -0.7178 -0.0831 0.7800 ? 2 i ? d Uiso 0.03320

14.8 Bragg’s Law and the X-Ray Spectrum
In Bragg’s law, nλ = 2 dhkl sin θhkl, where n is an integer, which is the order of the diffracted beam, λ
is the wavelength of the incoming beam, dhkl is the d-spacing, and θhkl is the Bragg angle for the (hkl)
planes. The d-spacing is a property of the crystal, the Bragg’s angle θhkl is an experimental observation, and the wavelength, λ, depends on the material in the x-ray tube. When high-speed electrons
from the cathode crash into the anode, characteristic discrete x-rays are emitted. Two examples of
the x-rays emitted are Kβ and Kα, where Kβ > Kα. The wavelength of these x-rays depends on the
atomic number, Z, of the material making up the anode. Table14.5 shows the characteristic radiation for several elements with their atomic number. Different experiments may require different
anodes in the x-ray tube.

14.9 Crystal Specimen Preparation for X-Ray Analysis
There are two general crystal preparations for x-ray analysis. The first is for x-ray powder analysis
and the second is for single-crystal analysis. These procedures complement one another. For x-ray

231

Crystallography

Table14.5
Characteristic Radiation for Several
Elements Commonly Used as Anodes
Atomic Number, Z

Element

Kα , Å

Kβ , Å

24
25
26
27
28
29

Cr
Mn
Fe
Co
Ni
Cu

2.29
2.10
1.94
1.79
1.66
1.54

2.08
1.91
1.76
1.62
1.50
1.39

Source: Julian, M. M., Foundations of Crystallography
with Computer Applications (Boca Raton,
FL: CRC Press, 2008), p. 266.

powder analysis the sample consists of many, maybe thousands, of tiny crystals oriented randomly.
The principal use of x-ray powders is for identification. For single-crystal analysis the idea is to
grow a single perfect crystal. The latter group can be further divided into protein crystallography,
or the study of biological macromolecules, and all other crystals.

14.9.1 Preparation of X-Ray Powders
Over 250,000 x-ray diffraction patterns have been compiled in a library by the Joint Committee on
Powder Diffraction Standards (JCPDS). Figure14.2 shows the Powder Diffraction File (PDF) for
hexamethylbenzene. The crystallographic information includes a literature reference, cell parameters, space group, volume of unit cell, density, intensity pattern, and identification of the diffraction

Figure 14.2 Powder Diffraction File (PDF) for hexamethylbenzene, PDF 33-1695.

232

Organic Chemist's Desk Reference, Second Edition
Crystal mounted on
goniometer head

Figure 14.3 Goniometer head holding a crystal. (Oxford Diffraction Ltd.)

peaks. Note there is a difference, within experimental error of the parameters, between Figure14.2
and Table14.4.
Crystalline material is ground into equiaxial, randomly oriented grains of about 50 µm.
Appropriate sieves can be used. The thin layer of crystals is spread onto a glass microscope slide or
a holder specially designed for the particular x-ray diffraction setup. If there is preferred rather than
random orientation of the grains, the diffraction pattern will be distorted.

14.9.2 Preparations of Single Crystals
Single-crystal analysis is generally more difficult than powder analysis, but the results are
more informative.
14.9.2.1 Protein Crystal Preparation
The growth of protein crystals is a difficult, complex, and often frustrating procedure. The protein
crystal is precipitated from a supersaturated solution of the macromolecule in which the protein is
partitioned between the solid phase and the solution. The pH value influences the solubility. Usually
a pH is chosen near the isoelectric point of the macromolecule. Inorganic salts, organic solvents, and
commercially available precipitating agents, such as the polymer PEG, can be helpful.
14.9.2.2 Single-Crystal Preparation (Nonmacromolecules)
The purer and more perfect the single crystal, the better the final analysis. The general methods are
growth from solutions, sublimation, and solid-state synthesis. Nucleation and growth are competing
processes that are usually performed in two stages. First, tiny crystals are quickly precipitated from
hot solutions. Then these microcrystals are slowly grown over days or months, sometimes under
refrigeration, until the appropriate size is reached.
Crystals that are unaffected by air, moisture, or light are usually mounted directly on a quartz or
glass fiber, which is inserted into a goniometer head (Figure14.3). If the crystal is sensitive to moisture or air, a sealed capillary tube may be used. Suitable apparatus can be used when nonambient
temperatures and pressures are needed. The diamond anvil has been developed for high pressure.

Endnotes

1. These definitions are adapted from Julian, M. M., Foundations of Crystallography with Computer
Applications (Boca Raton, FL: CRC Press, 2008), pp. 323–332.
2. Adapted from the library of crystal files in Centre for Innovation & Enterprise, CrystalMaker Software
Limited (Oxford: Oxford University, 2006).
3. Hahn, T., ed., International Tables for Crystallography: Space Group Symmetry, Vol. A (Dordrecht, The
Netherlands: International Union of Crystallography, Kluwer Academic Publishers, 2002).

15 Chromatographic
Chiral Separation
Nelu Grinberg
Chirality plays a major role in biological processes and enantiomers of a particular molecule can
often have different physiological properties. In some cases, enantiomers may have similar pharmacological properties with different potencies; for example, one enantiomer may play a positive
pharmacological role, while the other can be toxic. For this reason, advancements in asymmetric
synthesis, especially in the pharmaceutical industry and life sciences, has led to the need to assess
the enantiomeric purity of drugs. Chromatographic chiral separation plays an important role in this
domain. Today, there are a large number of chiral stationary phases on the market that facilitate the
assessment of enantiomeric purity.

15.1 Types of Molecular Interactions
When a compound is synthesized in an achiral environment, the reaction product is obtained as a
racemic mixture owing to the fact that in an achiral medium enantiomers are energetically degenerate and interact identically with the environment. Enantiomers can be differentiated only in a chiral
environment, provided the proper conditions are offered by the chiral environment. Chiral separation is a very good example of dynamic supramolecular chemistry. Supramolecular chemistry
aims at constructing highly complex, functional chemical systems held together by intermolecular
forces.1 Indeed, the interaction between the enantiomeric analytes (selectand) and the chiral phase
(selector) can be through hydrogen bonding, inclusion interactions, charge transfer (π-π interactions), ligand exchange, or a combination. The chirality of the selector or the selectand can arise
from an asymmetric carbon, the molecular asymmetry, or the helicity of a polymer. Also, the bonds
between substituents of the selectand and the selector can involve a single bond, but could also
involve multiple bonds or surfaces. Such bonds represent the leading interactions between selectand
and selector. Only when the leading interactions take place, and the asymmetric moieties of the
two bodies are brought into close proximity, do secondary interactions (e.g., van der Waals, steric
hindrance, dipole-dipole) become effectively involved. The secondary interaction can affect the
conformation and the energy of the diastereomeric associates. From a chromatographic point of
view, the primary interactions affect the retention of the analyte on the chiral column, while the
secondary interactions affect the enantioselectivity.2

15.2 Diastereomeric Compounds and Complexes
The chromatographic separation of enantiomers involves the formation of diastereomeric complexes
between the enantiomers and the chiral environment. These diastereomeric complexes can exist as
long-living species, or short-living complexes.
The long-living diastereomeric species are achieved by chemical reaction between a certain pair
of enantiomers and a chiral derivatizing reagent. They can be separated in an achiral environment.
Their formation energy has no relevance to their chromatographic separation. Their separation is

233

234

Organic Chemist's Desk Reference, Second Edition

due to the effect that their nonequivalent shape, size, or polarity, etc., has on their solvation energy.
Differences in their shape and size are related to the differences in the energy needed to displace
solvent molecules to create their nonequivalent solvation cage, while differences in all of the above
parameters determine their differential interactions with the solvent molecules in their solvation
cage.3 The formation of diastereomers through chemical reactions has some advantages and disadvantages. The main advantage is that it employs an achiral stationary phase column, which is much
cheaper than a chiral stationary phase column. The disadvantage stems from the fact that it relies
on the functional groups existent in the molecule, which are capable of being chemically modified. On the other hand, since diastereomers are molecular species with slightly different physical
properties, they may have different detector response factors upon elution from the column. As a
consequence, a calibration curve is required for each diastereomer when quantitation is needed. The
final quantitation results also rely on the purity of the derivatizing reagent.
Short-living diastereomeric species occur through the formation of transient diastereomeric
complexes between the enantiomers and the chiral moiety present in the chromatographic
column. Such complexes are usually not isolable and may be sufficiently energetically nondegenerate to be used to differentiate between a pair of enantiomers to be separated.4,5 In the
chromatographic system, the chiral agent is added into the mobile phase and constantly pumped
through an achiral chromatographic column (the approach is called chiral mobile phases
(CMPs)). Alternatively, the chiral agent is chemically bonded on a solid matrix such as silica gel
or a synthetic polymer (chiral stationary phases (CSPs)). Each approach has some advantages
and some disadvantages.

15.3 Chiral Mobile Phases
CMP’s advantages stem from the fact that it is cheaper, since it uses achiral stationary phases, and
the chiral additive can be purchased at a low cost; the approach is flexible, because after using a
chiral additive, the chromatographic column can be washed out from the chiral additive and a new
additive can be employed. On the other hand, the mechanism is difficult to predict due to the constant presence of a secondary chemical equilibrium in the column. Since the enantiomeric analytes
are eluted out of the column as diastereomeric complexes, the detector response may be different for
each complex. Also, the sample capacity is relatively small.

15.4 Chiral Stationary Phases
The CSP approach also has advantages and disadvantages. The advantages stem from the fact that
the mechanism of chiral separation is easier to predict. The enantiomers are eluted out of the column as enantiomeric entities; thus, they have the same detector response. The disadvantages consist
of the high price of chiral columns and the fact that, as in the case of CMPs, the sample capacity is
relatively small.

15.4.1 Chiral Separation by Hydrogen Bonding
ChirasilVal is a chiral phase that works through hydrogen bonding interactions between the selectand and the selector, and is well known for its use for gas chromatographic chiral separation of
amino acids. This chiral phase consists of a valine diamide incorporated into a polysiloxane. In
order to make the amino acid analytes volatile, the amino and the carboxyl groups are blocked
through an ester and an amide functional group, respectively. The interactions occur through hydrogen bonding between the amide and ester carbonyl functional groups of the selectand and the amide
functional groups of the selector.

Chromatographic Chiral Separation

235

15.4.2 Chiral Separation by Inclusion Complexes
Cyclodextrins and chiral crown ethers are chiral phases where the predominant interactions are
through inclusion. They are classified as host-guest complexes. These complexes are structured by
contacts at multiple sites between the hosts (chiral phase) and the guests (enantiomeric analytes).
The host can have a hydrophobic interior (i.e., cyclodextrins) or a hydrophilic interior (i.e., chiral
crown ethers). The hydrophilic interior means that the cavity contains heteroatoms such as oxygen,
where the lone pair electrons are able to participate in hydrogen bonding with compounds such as
organic cations (i.e., ammonium ions). The chromatographic separation on these chiral phases is
modulated by the addition of organic modifiers, such as alcohols or acetonitrile in aqueous buffers
or mixtures of alcohols.

15.4.3 Chiral Separation by π-π Interactions, Hydrogen Bonding, and Ion Pairing
Another group consists of chiral phases, which work through a combination of π-π interactions with
hydrogen bonding or π-π interactions with electrostatic interactions. The first group encompasses
Pirckle type phases,6–8 while the latter includes the Cinchona alkaloids type CSP.9 The Pirckle type
phases are based on derivatized amino acids with an aromatic moiety that can be either a π donor
or a π acceptor. These chiral moieties are chemically bounded to silica gel. These CSPs undergo
π-π interaction with selectands that have an aromatic moiety. The complex is stabilized through
additional interactions such as hydrogen bonding, dipole-dipole interactions, or steric repulsion. An
improved chiral stationary phase synthesized by Pirckle’s group possesses both dinitrobenzoyl and
naphthyl moiety, allowing for simultaneous face-to-face π-π interactions and phase-to-edge interactions. Such chiral phases operate with mobile phases consisting of a mixture of organic solvents
such as hexane isopropanol.
The cinchona alkaloid-based stationary phases are chiral stationary phases where quinine/
quinidine are chemically bonded to a silica gel matrix. The interaction between the selectand and
selector is based on charge transfer π-π interactions as well as ion pairing with the selector. They operate under aqueous-organic mobile phases or mixtures of organic solvents such as hexane-alcohols.

15.4.4 Chiral Separation by Ligand Exchange
Ligand exchange chromatography (LEC) is the typical example of complexation chromatography.
Complexes formed during LEC consist of a metal cation associated with ligands (anion or neutral
molecules) that is able to donate electron pairs to a vacant orbital of the metal.10 This technique is
applicable for those enantiomers that are able to form metal complexes with the chiral moiety that
is anchored to the stationary phase. Enantiomeric analytes such as amino acids and hydroxy acids
were successfully separated using LEC. The technique uses aqueous-organic mobile phases containing a transition metal such as copper(II).

15.4.5 Chiral Separation by a Combination of Interactions
There are also stationary phases that interact with the selectands through a combination of the interactions, such as hydrogen bonding, π-π interactions, inclusion, hydrophobic interactions, and electrostatic interactions. These stationary phases include polysaccharides (cellulose derivatives, amylose
derivatives),11 protein phases,12 and macrocyclic antibiotic phases.13 The polysaccharide phases operate under mobile phase conditions that include aqueous-organic and mixtures of organic solvents such
as hexane-alcohols. The protein phases operate under mixtures of aqueous-organic mobile phases,
while the macrocycle mobile phases operate under mixtures of aqueous-organic mobile phases, as
well as mixtures of acetonitrile-methanol with small amounts of additives (acetic acid and triethyl
amine)—polar organic mobile phases.

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Organic Chemist's Desk Reference, Second Edition

References

1. J.-M. Lehn. From supramolecular chemistry toward constitutional dynamic chemistry and adaptive
chemistry. Chem. Soc. Rev. 36 (2007) 151.
2. N. Grinberg. Chiral separation in pharmaceutical industry. Am. Pharm. Rev. 9 (2006) 65.
3. B. Feibush. Chiral separation via selector/selectand hydrogen bonding. Chirality 10 (1998) 382.
4. N. Grinberg, T. Burokowski, and A. M. Stalcup. HPLC for pharmaceutical scientists, ed. Y. Cazakevich
and R. Lobrutto. Hoboken, NJ: John Wiley & Sons, 2007.
5. W. H. Pirkle and T. C. Pochapsky. Theory and design of chiral stationary phases for direct chromatographic separation. In Packing and stationary phases in chromatographic techiques, ed. K. Unger. New
York: Marcel Dekker, 1990.
6. W. H. Pirckle, C. J. Welch, and B. Lamm. Design, synthesis and evaluation of an improved enantioselective naproxen selector. J. Org. Chem. (1992) 3854.
7. W. H. Pirckle, D. W. House, and J. M. Finn. Broad spectrum resolution of optical isomers using chiral
high performance liquid chromatography bonded phases. J. Chromatogr. A 192 (1980) 143.
8. W. H. Pirckle and D. L. Sikkenga. Resolution of optical isomers by liquid chromatography. J. Chromatogr.
A 123 (1976) 400.
9. M. Lammerhofer and W. Lindner. Liquid chromatographic enantiomer separation and chiral recognition
by Cinchona alkaloid-derived enantioselective separation materials. In Advances in Chromatography,
Vol. 46, ed. E. Grushka and N. Grinberg. Boca Raton, FL: CRC Press, Taylor & Francis Group, 2008.
10. V. A. Davankov. Ligand exchange chromatography of chiral compounds. In Complexation chromatography, ed. D. Cagniant. New York: Marcel Dekker, 1992.
11. T. Ikai and Y. Okamoto. Structure control of polysaccharide derivatives for efficient separation of enantiomers by chromatography. Chem. Rev., 109 (2009) 6077.
12. S. R. Narayanan. Imobilized proteins as chromatographic support for chiral resolution. J. Pharm. Biol.
Anal. 10 (1992) 251.
13. I. D’Acquarica, F. Gasparini, D. Misiti, M. Pierini, and C. Villani. HPLC chiral stationary phases containing macrocyclic antibiotics. In Advances in Chromatography, Vol. 46, ed. E. Grushka and N. Grinberg.
Boca Raton, FL: CRC Press, Taylor & Francis Group, 2008.

16 Laboratory Data and SI Units
16.1 Solvents
16.1.1 Polarity of Common Laboratory Solvents
Solvents may be classified according to their polarity into three groups: apolar aprotic solvents,
dipolar aprotic solvents, and (polar) protic solvents. Examples of these three classifications for
some common laboratory solvents are listed in Table16.1, in order of increasing polarity (indicated
by dielectric constant), together with some other solvent properties. For information on the hazards
and toxicity of solvents, see Chapter 11.
Table16.1
Polarity Classifications and Some Properties of Common
Laboratory Solvents

Solventa

Bp (°C)
(760 mmHg)

Mp (°C)

Dielectric
Constant (ε)
at 25ºCb

Density
(g/ml)
at 20ºCc

Solubility of
Solvent in Water
(wt%) at 25ºC

Hexane
Benzene
Toluene
Diethyl ether
Chloroform
Ethyl acetate

69
80
111
35
61
77

Apolar Aprotic Solvents
–94
1.9
+6
2.3
–95
2.4
–116
4.3 (20°C)
–63
4.8 (20°C)
–84
6.0

0.66
0.88
0.87
0.71
1.49
0.90

0.002
0.18
0.05
6.0
0.82 (20ºC)
8.1

1,4-Dioxane
Tetrahydrofuran
Dichloromethane
Acetone
Acetonitrile
Dimethylformamide
Dimethyl sulfoxide

101
66
40
56
82
153
189

Dipolar Aprotic Solvents
+12
2.2
–109
7.6
–95
8.9
–94
20.7
–45
37.5 (20°C)
–61
37.0
+19
46.7

1.03
0.89
1.33
0.79
0.79
0.94
1.10

Miscible
Miscible
1.30
Miscible
Miscible
Miscible
25.3

Acetic acid
1-Butanol
2-Propanol
1-Propanol
Ethanol
Methanol
Formic acid
Water

118
118
82
97
78
65
101
100

Protic Solvents
+17
6.2 (20°C)
–89
17.5
–88
19.9
–126
20.3
–117
24.6
–98
32.7
+8
58.5
0
78.4

1.05
0.81
0.79
0.80
0.79
0.79
1.22
1.000

Miscible
7.45
Miscible
Miscible
Miscible
Miscible
Miscible
––

(continued on next page)

237

238

Organic Chemist's Desk Reference, Second Edition

Table16.1 (continued)
Polarity Classifications and Some Properties of Common
Laboratory Solvents
a

For more data on solvents, see Riddick, J. A., et al., Organic Solvents: Physical Properties and
Methods of Purification, 4th ed. (Chichester: Wiley, 1986) and Lide, D. R., Handbook of Organic
Solvents (Boca Raton, FL: CRC Press, 1995).
For a detailed discussion of some quantitative indicators of solvent polarity, including dielectric
constant, see Reichardt, C., Solvent Effects in Organic Chemistry (Weinheim: Verlag Chemie, 1979),
pp. 49–51, etc.
Densities of solvents heavier than water are in bold type.

16.1.2 Solvents Used for Recrystallisation
Many solids may be purified by recrystallisation by dissolving the substance in a minimum quantity of hot solvent, filtering the solution, and then cooling the solution so that crystals of the desired
substance form while the impurities remain in solution. A list of solvents commonly used for
recrystallisation is given in Table16.2.
In order to be useful, a solvent should dissolve much of the solid substance at higher temperatures
and very little of it at lower temperatures. It should not react with the compound. Solvents with a
high boiling point should be avoided if possible. Impurities do not have to be more soluble in the
cold solvent than the substance being purified. Since the impurities are present at a lower concentration, they will frequently remain in solution even though less soluble.
In general, polar compounds (e.g., alcohols, thiols, amines, carboxylic acids, amides) tend to
dissolve in (polar) protic solvents (e.g., water, alcohols). Nonpolar compounds tend to dissolve in
(nonpolar) aprotic solvents (e.g., benzene, petrol, hexane).
Often it is possible to use a mixture of miscible solvents where the substance to be recrystallised is soluble in one of the solvents but relatively insoluble in the other. The solute can be dissolved hot in a suitable solvent mixture, which is then allowed to cool. Alternatively, the solute can
be dissolved in the solvent in which it is more soluble either at elevated or at room temperature; the
other solvent is then added until crystallisation just begins, and the resulting mixture is cooled to
further induce recrystallisation.
Table16.2
Solvents Commonly Used for Recrystallisation (solvents listed in approximate order of
decreasing polarity)

Solventa

Bp (°C)
(760
mmHg)

Mp (°C)

Flash Point
(°C);
Flammability
Classification

Water

100

None

Salts, amides,
carboxylic
acids

Methanol

–98

10; highly
flammable

Many
compounds

Good for

Second Solvent
for Mixture

Commentsb

Acetone,
Products dry
ethanol,
slowly
methanol,
dioxane
Water, diethyl
ether,
dichloromethane,
benzene

239

Laboratory Data and SI Units

Table16.2 (continued)
Solvents Commonly Used for Recrystallisation (solvents listed in approximate order of
decreasing polarity)
Flash Point
(°C);
Flammability
Classification

Good for

–117

12; highly
flammable

Many
compounds

–94

–17; highly
flammable

Many
compounds

2-Methoxyethanol

125

–86

43; flammable

Sugars

Pyridine

116

–42

20; flammable

High-melting
compounds

Dichloromethane

–95

None

Low-melting
compounds

Methyl acetate

–98

Acetic acid

118

+17

–9; highly
flammable
39; flammable

Ethyl acetate

–84

–4; highly
flammable

Many
compounds
Salts, amides,
carboxylic
acids
Many
compounds

Chloroform

–63

None

Many
compounds

Diethyl ether

–116

–45; extremely
flammable

Low-melting
compounds

1,4-Dioxane

101

+12

11; highly
flammable

Amides

Solventa

Bp (°C)
(760
mmHg)

Mp (°C)

Ethanol

Acetone

Second Solvent
for Mixture
Water, petrol,
pentane,
hexane, ethyl
acetate
Water, petrol,
pentane,
hexane, diethyl
ether
Water, benzene,
diethyl ether
Water, methanol,
petrol, pentane,
hexane
Ethanol,
methanol,
petrol, pentane,
hexane
Water, diethyl
ether
Water

Diethyl ether,
benzene, petrol,
pentane,
hexane
Ethanol, petrol,
pentane,
hexane

Acetone,
methanol,
ethanol, petrol,
pentane hexane
Water, benzene,
petrol, pentane,
hexane

Commentsb

Must not be used
in combination
with chloroform

Difficult to remove

Easily removed

Difficult to
remove; pungent
odour

Hepatotoxic and
nephrotoxic; must
not be used in
combination with
acetone; traces
can affect
microanalytical
data

Peroxidation
hazard

(continued on next page)

240

Organic Chemist's Desk Reference, Second Edition

Table16.2 (continued)
Solvents Commonly Used for Recrystallisation (solvents listed in approximate order of
decreasing polarity)
Bp (°C)
(760
mmHg)

Mp (°C)

Flash Point
(°C);
Flammability
Classification

Tetrachloromethane
(carbon
tetrachloride)

–21

None

Nonpolar
compounds

Diethyl ether,
benzene, petrol,
pentane, hexane

Toluene

111

–95

4; highly
flammable

Aromatics,
hydrocarbons

Benzene

–11; highly
flammable

Aromatics,
hydrocarbons

Petrol

—c

Hydrocarbons

Pentane

–129

Hydrocarbons

Most solvents

Hexane

–94

–40; extremely
flammable
–49; extremely
flammable
–23; highly
flammable

Diethyl ether,
ethyl acetate,
petrol, pentane,
hexane
Diethyl ether,
ethyl acetate,
petrol, pentane,
hexane
Most solvents

Hydrocarbons

Most solvents

Solventa

Good for

Second Solvent
for Mixture

Commentsb
Reacts with some
nitrogen bases;
hepatotoxic and
nephrotoxic;
traces can affect
microanalytical
data

Human carcinogen
(IARC Group 1)

Source: Based on information in Gordon, A. J., and Ford, R. A., The Chemist’s Companion (New York: Wiley-Interscience,
1972), pp. 442–443. Reprinted with permission of John Wiley & Sons, Inc.
a For more data on solvents, see Riddick, J. A., et al., Organic Solvents: Physical Properties and Methods of Purification,
4th ed. (Chichester: Wiley, 1986) and Lide, D. R., Handbook of Organic Solvents (Boca Raton, FL: CRC Press, 1995).
b Comments apply to the main solvent.
c Petrol refers to a mixture of alkanes obtainable in a number of grades based on boiling ranges, e.g., 40–60°C and 60–80°C.

16.1.3 Solvents Used for Extraction of Aqueous Solutions
A list of some solvents suitable for the extraction of aqueous solutions is given in Table16.3.

Table16.3
Solvents for Extracting Aqueous Solutions

Solvent

Bp (°C)
(760 mmHg)

Density
Relative
to Water

Solubility of
Solvent in
Water (wt%)

Solubility of
Water in
Solvent (wt%)

Benzene
2-Butanol

80
99

Lighter
Lighter

0.18
12.5

0.06
44.1

Comments
Tends to form emulsion
Dries easily; good for highly
polar water-soluble materials
from buffered solution

241

Laboratory Data and SI Units

Table16.3 (continued)
Solvents for Extracting Aqueous Solutions

Solvent

Bp (°C)
(760 mmHg)

Density
Relative
to Water

Solubility of
Solvent in
Water (wt%)

Solubility of
Water in
Solvent (wt%)

Tetrachloromethane
(carbon
tetrachloride)
Chloroform
Diethyl ether
Diisopropyl ether
Ethyl acetate

Heavier

0.08

0.01

61
35
69
77

Heavier
Lighter
Lighter
Lighter

0.82
6.04
1.2
8.08

0.09
1.47
0.57
2.94

Dichloromethane

Heavier

1.30

0.02

Pentane
Hexane

36
69

Lighter
Lighter

0.004
0.002

0.01
0.01

Comments
Dries easily; good for nonpolar
materials; environmental
hazard
May form emulsion; dries easily
Absorbs large amounts of water
Tends to peroxidise on storage
Absorbs large amounts of
water; good for polar materials
May form emulsions; dries
easily
Dries easily
Dries easily

Source: Based, in part, on information in Gordon, A. J., and Ford, R. A., The Chemist’s Companion (New York: WileyInterscience, 1972), p. 444. Reprinted with permission of John Wiley & Sons, Inc.

16.1.4 Commercial and Common Name Solvents
See Table16.4.
Table16.4
Commercial and Common Name Solvents
Commercial Name

Chemical Name

Molecular
Formula

(a) Carbitols. Diethylene Glycol Ethers (ROCH2CH2OCH2CH2OR’)
Methyl carbitol
2-(2-Methoxyethoxy)ethanol
C5H12O3
Carbitol; ethyl carbitol
2-(2-Ethoxyethoxy)ethanol
C6H14O3
Diethyl carbitol
C8H18O3
1,1′-Oxybis[2-ethoxyethane];
bis(2-ethoxyethyl) ether
(b) Cellosolves. Ethylene glycol ethers (ROCH2CH2OR’)
Cellosolve
2-Ethoxyethanol
Dimethylcellosolve; glyme
1,2-Dimethoxyethane
Diethylcellosolve
1,2-Diethoxyethane
Methylcellosolve
2-Methoxyethanol
Cellosolve acetate
2-Ethoxyethyl acetate
Butylcellosolve
2-Butoxyethanol

C4H10O2
C4H10O2
C6H14O
C3H8O2
C6H12O3
C6H14O2

R’

Bp (°C) (760
mmHg)

Me
Et
Et

H
H
Et

193
195
189

Et
Me
Et
Me
Et
Bu

H
Me
Et
H
COCH3
H

135 (743 mmHg)
85
121
124
156
171

Chemical Name

Molecular
Formula

Bp (°C) (760
mmHg)

Glyme; dimethylcellosolve
Diglyme

1,2-Dimethoxyethane

1
2

C4H10O2
C6H14O3

83
161

1,1′-Oxybis[2-methoxyethane],
bis(2-methoxyethyl) ether

(continued on next page)

242

Organic Chemist's Desk Reference, Second Edition

Table16.4 (continued)
Commercial and Common Name Solvents
Commercial Name

Chemical Name

Molecular
Formula

Bp (°C) (760
mmHg)

Triglyme
Tetraglyme

1,2-Bis(2-methoxyethoxy)ethane
2,5,8,11,14-Pentaoxapentadecane

3
4

C8H18O4
C10H22O5

216
275–276;
119 (2 mmHg)

Kerosene (also kerosine)
Naphtha

Petroleum ether (light
petroleum)

Skellysolves
Skellysolve A
Skellysolve B
Skellysolve C
Skellysolve D
Skellysolve E
Skellysolve F
Skellysolve G

(d) Hydrocarbon Petroleum Fractions
A distillate mixture obtained from crude petroleum, boiling range about 150–300°C.
A generic term for hydrocarbon distillates produced from either petroleum or coal tar.
Petroleum naphthas are mixtures of hydrocarbons obtained as distillate fractions from
crude petroleum, e.g., with a bp range 175–240°C. The term naphtha is also applied to
other (and narrower) bp ranges. Solvent naphtha is a coal-tar distillate consisting mainly
of aromatic hydrocarbons.
Fractions of refined petroleum containing mainly short-chain hydrocarbons (pentane,
hexane, and heptane isomers) with specified boiling point ranges, e.g., 40–60°C, 60–80°C,
80–100°C, and 100–120°C. The term ligroin is sometimes used for higher-boiling-point
petroleum ether fractions (typically 130–145°C), but is also associated with lower bp
ranges. In the older chemical literature, petroleum ether, petroleum spirits, ligroin, naphtha,
and petroleum benzin(e) are synonyms.
Saturated hydrocarbon mixtures:
Mostly pentane, bp range 28–38°C
Mostly hexane, bp range 60–71°C
Mostly heptane, bp range 88–100°C
Mixed heptanes, bp range 80–119°C
Mixed octanes, bp range 100–140°C
Petroleum ether, bp range 35–60°C
Petroleum ether, bp range 40–75°C

16.2 Buffer Solutions
A list of buffer solutions that show round values of pH at 25°C is given in Table16.5. The final volume of all the mixtures is adjusted to 100 ml.
Table16.5
Buffer Solutionsa Giving Round Values at 25°C
A

1.00
1.10
1.20
1.30
1.40
1.50
1.60
1.70
1.80
1.90

67.0
52.8
42.5
33.6
26.6
20.7
16.2
13.0
10.2
8.1

2.20
2.30
2.40
2.50
2.60
2.70
2.80
2.90
3.00
3.10

49.5
45.8
42.2
38.8
35.4
32.1
28.9
25.7
22.3
18.8

4.10
4.20
4.30
4.40
4.50
4.60
4.70
4.80
4.90
5.00

1.3
3.0
4.7
6.6
8.7
11.1
13.6
16.5
19.4
22.6

5.80
5.90
6.00
6.10
6.20
6.30
6.40
6.50
6.60
6.70

3.6
4.6
5.6
6.8
8.1
9.7
11.6
13.9
16.4
19.3

7.00
7.10
7.20
7.30
7.40
7.50
7.60
7.70
7.80
7.90

46.6
45.7
44.7
43.4
42.0
40.3
38.5
36.6
34.5
32.0

243

Laboratory Data and SI Units

Table16.5 (continued)
Buffer Solutionsa Giving Round Values at 25°C
A

2.00
2.10
2.20

6.5
5.1
3.9

3.20
3.30
3.40
3.50
3.60
3.70
3.80
3.90
4.00

15.7
12.9
10.4
8.2
6.3
4.5
2.9
1.4
0.1

5.10
5.20
5.30
5.40
5.50
5.60
5.70
5.80
5.90

25.5
28.8
31.6
34.1
36.6
38.8
40.6
42.3
43.7
43.5
44.5
45.3
46.1

6.80
6.90
7.00
7.10
7.20
7.30
7.40
7.50
7.60
7.70
7.80
7.90
8.00

22.4
25.9
29.1
32.1
34.7
37.0
39.1
40.9
42.4

8.00
8.10
8.20
8.30
8.40
8.50
8.60
8.70
8.80
8.90
9.00

29.2
26.2
22.9
19.9
17.2
14.7
12.2
10.3
8.5
7.0
5.7

8.00
8.10
8.20
8.30
8.40
8.50
8.60
8.70
8.80
8.90
9.00
9.10

20.5
19.7
18.8
17.7
16.6
15.2
13.5
11.6
9.6
7.1
4.6
2.0

9.20
9.30
9.40
9.50
9.60
9.70
9.80
9.90
10.00
10.10
10.20
10.30
10.40
10.50
10.60
10.70
10.80

0.9
3.6
6.2
8.8
11.1
13.1
15.0
16.7
18.3
19.5
20.5
21.3
22.1
22.7
23.3
23.8
24.25

9.60
9.70
9.80
9.90
10.00
10.10
10.20
10.30
10.40
10.50
10.60
10.70
10.80
10.90
11.00

5.0
6.2
7.6
9.1
10.7
12.2
13.8
15.2
16.5
17.8
19.1
20.2
21.2
22.0
22.7

10.90
11.00
11.10
11.20
11.30
11.40
11.50
11.60
11.70
11.80
11.90
12.00

3.3
4.1
5.1
6.3
7.6
9.1
11.1
13.5
16.2
19.4
23.0
26.9

12.00
12.10
12.20
12.30
12.40
12.50
12.60
12.70
12.80
12.90
13.00

6.0
8.0
12.2
12.8
16.2
20.4
25.6
32.2
41.2
53.0
66.0

Source: Reproduced with permission from CRC Handbook of Chemistry and Physics 2008–2009, 89th ed., D. R. Lide
(Boca Raton, FL: CRC Press, 2008).
a The buffer solutions are made up as follows:
(A) 25 ml of 0.2 molar KCl + x ml of 0.2 molar HCl
(B) 50 ml of 0.1 molar potassium hydrogen phthalate + x ml of 0.1 molar HCl
(C) 50 ml of 0.1 molar potassium hydrogen phthalate + x ml of 0.1 molar NaOH
(D) 50 ml of 0.1 molar potassium dihydrogen phosphate + x ml 0.1 molar NaOH
(E) 50 ml of 0.1 molar tris(hydroxymethyl)aminomethane + x ml of 0.1 molar HCl
(F) 50 ml of 0.025 molar borax + x ml of 0.1 molar HCl
(G) 50 ml of 0.025 molar borax + x ml of 0.1 molar NaOH
(H) 50 ml of 0.05 molar sodium bicarbonate + x ml of 0.1 molar NaOH
(I) 50 ml of 0.05 molar disodium hydrogen phosphate + x ml of 0.1 molar NaOH
(J) 25 ml of 0.2 molar KCl + x ml 0.2 molar NaOH

244

Organic Chemist's Desk Reference, Second Edition

16.3 Acid and Base Dissociation Constants
16.3.1 First Dissociation Constants of Organic Acids in Aqueous Solution at 298 K
The pKa1 values are shown in Table16.6.

Table16.6
The pKa1 Values of Some Organic Acids in Aqueous Solution at
298 K
pKa1

Compound

pKa1

Compound

0.17
0.29
0.66
0.70
1.10
1.25
1.48
1.70
1.71
1.75
1.82
1.83
1.95
1.99
2.04
2.09
2.14
2.17
2.17
2.17
2.19
2.20
2.23
2.23
2.29
2.32
2.32
2.35
2.35
2.35
2.49
2.69
2.85
2.86

1-Naphthalenesulfonic acid
2,4,6-Trinitrophenol
Trichloroacetic acid
Benzenesulfonic acid
Nitrilotriacetic acid
Oxalic acid
Dichloroacetic acid
Histidine
Cysteine
2-Butynedioic acid
Arginine
Maleic acid
Proline

3.12
3.13
3.17
3.22
3.23
3.33
3.40
3.44
3.46
3.49
3.51
3.54
3.60
3.70
3.74
3.83
3.86
3.91
4.01
4.08
4.09
4.16
4.17
4.20
4.26
4.27
4.30
4.31
4.34
4.36
4.43
4.44
4.48
4.58
4.69
4.78
4.78
4.78
4.83

Iodoacetic acid
Citric acid
2-Furancarboxylic acid
Tartaric acid (meso-)
2-Aminobenzoic acid
Ethanethioic acid
Hydroxybutanedioic acid
4-Nitrobenzoic acid
Glyoxylic acid
3-Nitrobenzoic acid
1,4-Benzenedicarboxylic acid
1,3-Benzenedicarboxylic acid
Mercaptoacetic acid
1-Naphthalenecarboxylic acid
Formic acid
Hydroxyacetic acid
2-Hydroxypropanoic acid
2-Methylbenzoic acid
2,4,6(1H,3H,5H)-Pyrimidinetrione
3-Hydroxybenzoic acid
2,4-Dinitrophenol
Succinic acid
2-Naphthalenecarboxylic acid
Benzoic acid
2-Propenoic acid
3-Methylbenzoic acid
Ascorbic acid
Phenylacetic acid
Pentanedioic acid
4-Methylbenzoic acid
Hexanedioic acid
3-Phenyl-2-propenoic acid (E-)
Heptanedioic acid
4-Hydroxybenzoic acid
2-Butenoic acid (E-)
Acetic acid
3-Methylbutanoic acid
3-Aminobenzoic acid
Butanoic acid

2.89
2.95
2.97
2.98
3.05

Aspartic acid (α-COOH)
Lysine
Threonine
Asparagine
Glutamine
Tyrosine
2-Nitrobenzoic acid
Serine
Methionine
Glutamic acid (α-COOH)
Fluoroacetic acid
Valine
Isoleucine
Leucine
Glycine
Tryptophan
Alanine
Pyruvic acid
Bromoacetic acid
Propanedioic acid
Chloroacetic acid
1,2-Benzenedioic acid
Phosphoric acid
2-Hydroxybenzoic acid
Tartaric acid ((±)-)
Fumaric acid

245

Laboratory Data and SI Units

Table16.6 (continued)
The pKa1 Values of Some Organic Acids in Aqueous Solution at
298 K
pKa1

Compound

pKa1

Compound

4.84
4.84
4.85
4.87
4.88
4.89
4.92
4.96
5.03
5.22
5.52
8.49

Pentanoic acid
2-Methylpropanoic acid
3-Pyridinecarboxylic acid
Propanoic acid
Hexanoic acid
Octanoic acid
4-Aminobenzoic acid
4-Pyridinecarboxylic acid
2,2-Dimethylpropanoic acid
3,6-Dinitrophenol
2-Pyridinecarboxylic acid
2-Chlorophenol

8.85
9.12
9.18
9.34
9.51
9.91
9.99
10.01
10.17
10.20
14.15

3-Chlorophenol
1,2-Benzenediol
4-Chlorophenol
1-Naphthol
2-Naphthol
1,4-Benzenediol
Phenol
3-Methylphenol
4-Methylphenol
2-Methylphenol
Glycerol

16.3.2 Dissociation Constants of Organic Bases in Aqueous Solution at 298 K
The pKa values of some bases are listed in Table16.7. The dissociation constant of a base B is given
in terms of the pKa value of its conjugate acid BH+. The pKb of a base may be calculated from the
pKa value of its conjugate acid using the equation

pKb = pKw – pKa

At 298 K this becomes

pKb = 14.00 – pKa
Table16.7
The pKa Values of Some Organic Bases in Aqueous Solution at 298 K
pKa

Compound

0.10
0.60
0.63
0.65
0.79
1.00
2.24
2.30
2.30
2.44
2.47
2.48
2.61
2.65
2.70

Urea
1,2-Benzenediamine
Acetamide
Pyrazine
Diphenylamine
4-Nitroaniline
Pyridazine
1,3-Benzenediamine
Purine
Thiazole
3-Nitroaniline
Pyrazole
N,N-Diethylaniline
2-Chloroaniline
1,4-Benzenediamine

pKa
3.12
3.52
3.92
4.05
4.12
4.13
4.14
4.16
4.35
4.45
4.60
4.66
4.73
4.78
4.85

Compound
Nicotine
3-Chloroaniline
1-Naphthaleneamine
Pteridine
Adenine
Quinine
4-Chloroaniline
2-Naphthaleneamine
2,2′-Bipyridine
2-Methylaniline
Aniline
4,4′-Biphenyldiamine
3-Methylaniline
2-Aminophenol
N-Methylaniline
(continued on next page

246

Organic Chemist's Desk Reference, Second Edition

Table16.7 (continued)
The pKa Values of Some Organic Bases in Aqueous Solution at 298 K
pKa

Compound

4.86
4.88
4.91
5.08
5.12
5.15
5.23
5.33
5.42
5.58
5.68
5.96
5.97
6.02
6.15
6.57
6.61
6.82
6.85
6.99
6.99
7.76
8.01
8.28
8.49

1,10-Phenanthroline
Quinoline
8-Hydroxyquinoline
4-Methylaniline
N-Ethylaniline
N,N-Dimethylaniline
Pyridine
Piperazine
Isoquinoline
Acridine
3-Methylpyridine
Hydroxylamine
2-Methylpyridine
4-Methylpyridine
3,5-Dimethylpyridine
2,3-Dimethylpyridine
1,2-Propanediamine
2-Aminopyridine
1,2-Ethanediamine
2,4-Dimethylpyridine
Imidazole
Tris(2-hydroxyethyl)amine
2-Amino-2-hydroxymethyl-1,3-propanediol
Brucine
Morpholine

pKa
8.88
9.03
9.11
9.35
9.50
9.80
10.41
10.56
10.56
10.60
10.61
10.64
10.64
10.64
10.64
10.71
10.72
10.77
10.83
10.93
11.12
11.30
12.34
13.54

Compound
Diethanolamine
1,3-Propanediamine
4-Aminopyridine
Benzylamine
2-Aminoethanol
Trimethylamine
2-Methylpropylamine
2-Butylamine
Hexylamine
2-Propylamine
Butylamine
Decylamine
Cyclohexylamine
Ethylamine
Methylamine
Propylamine
Triethylamine
Dimethylamine
tert-Butylamine
Diethylamine
Piperidine
Pyrrolidine
1,8-Bis(dimethylamino)naphthalene
Guanidine

16.4 Resolving Agents
In practice, resolution of an organic compound requires a good deal of trial and error. For information on resolution techniques see Stereochemistry, Fundamentals, and Methods, ed. H. B. Kagan,
Vol. 3 (Stuttgart Georg Thieme Verlag, 1977).

16.4.1 Bases
2-Amino-3-methyl-1-butanol
2-Amino-1-(4-nitrophenyl)-1,3-propanediol
2-Amino-1-phenyl-1-propanol (norephedrine, norpseudoephedrine)
2-Amino-3-phenyl-1-propanol
N-Isopropylphenylalaninol
Brucine
Cinchonidine
Cinchonine
2,2′-Diamino-1,1′-binaphthyl
2-Methyl-2-phenylbutanedioic acid anhydride
1-(1-Naphthyl)ethylamine
1-Phenyl-1-propylamine

Laboratory Data and SI Units

1-Phenyl-2-propylamine
Quinine
Sparteine
Strychnine
Plus many suitable derivatives of common protein amino acids

16.4.2 Acids
(1,1′-Binaphthalene)-2,2′-dicarboxylic acid
3-Bromo-8-camphorsulfonic acid
Camphor-8-sulfonic acid
Camphor-10-sulfonic acid
7,7-Dimethyl-2-oxobicyclo[2.2.1]heptane-1-carboxylic acid
2,3:4,6-Di-O-isopropylidene-xylo-hexulosonic acid
4-Hydroxydinaphtho[2,1-d:1′,2′-f]-1,3,2-dioxaphosphepin 4-oxide
4-Hydroxy-3-phenylbutanoic acid lactone
Mosher’s reagent
Lactic acid and many of its derivatives
Mandelic acid and many of its derivatives
3-Menthoxyacetic acid
3-Menthylglycine
2-Methyl-2-phenylbutanedioic acid
Naproxen
5-Oxo-2-pyrrolidinecarboxylic acids
2-[((Phenylamino)carbonyl)oxy]propanoic acid
1-Phenylethanesulfonic acid
Tartaric acid and many of its derivatives
1,2,3,4-Tetrahydro-3-isoquinolinesulfonic acid
(2,4,5,7-Tetranitro-9-fluorenylideneaminoxy)propanoic acid
4-Thiazolidinecarboxylic acid
Plus many suitable derivatives of common protein amino acids

16.4.3 Others
Camphor-10-sulfonyl chloride
Chrysanthemic acid chloride
(1,1′-Binaphthalene)-2,2′-diol
Camphor
2,2′-Dimethoxybutanedioic acid bis(dimethylamide)
3,3-Dimethyl-2-butanol
7,7-Dimethyl-2-oxobicyclo[2.2.1]heptane-1-carbonyl chloride
2,2-Dimethyl-α,α,α′,α′-tetraphenyl-1,3-dioxolane-4,5-dimethanol
α-Methoxy-α-(trifluoromethyl)benzeneacetic acid chloride
1-(1-Isocyanatoethyl)naphthalene
Menthol and its stereoisomers
3-Menthoxyacetyl chloride
N-Methanesulfonylphenylalanyl chloride
Methyl phenyl sulfoximine
2-Phenylpropanoic acid chloride
Tri-O-thymotide

247

248

Organic Chemist's Desk Reference, Second Edition

16.5 Freezing Mixtures
A list of some freezing mixtures and their approximate temperatures is given in Table16.8.
Table16.8
Freezing Mixturesa

100 g water
100 g water
100 g water
100 g water
100 g water
100 g water
100 g ice
100 g water
100 g ice
100 g ice
100 g ice
100 g ice
100 g ice
100 g ice
100 g ice
100 g ice
Ethylene glycol
Aq. calcium chloride
(various concentrations)
Octane
Ethanol
Chloroform
Acetone
2-Propanol
Diethyl ether

Components

Approximate Final
Temperature (°C)b

100 g ice
30 g ammonium chloride
75 g sodium nitrate
85 g sodium acetate
110 g sodium thiosulfate pentahydrate
36 g sodium chloride
30 g potassium chloride
133 g ammonium thiocyanate
45 g ammonium nitrate
33 g sodium chloride
81 g calcium chloride hexahydrate
66 g sodium bromide
105 g ethanol
85 g magnesium chloride
123 g calcium chloride hexahydrate
143 g calcium chloride hexahydrate
carbon dioxide (solid)
carbon dioxide (solid)

0
–5
–5
–5
–8
–10
–11
–18
–17
–21
–21
–28
–30
–34
–40
–55
-11
–30 to –45

carbon dioxide (solid)
carbon dioxide (solid)
carbon dioxide (solid)
carbon dioxide (solid)
carbon dioxide (solid)
carbon dioxide (solid)

–56
–72
–77
–78
–78
–100

Source: Based, in part, on data in Gordon, A. J., and Ford, R. A., The Chemist’s Companion
(New York: Wiley-Interscience, 1972), pp. 451–452. Reprinted with permission of
John Wiley & Sons, Inc.
a Experimental work with cooling baths and Dewar flasks containing freezing mixtures
requires the use of efficient fume hoods and personal protection equipment.
b The minimum temperatures reached with salt-ice mixtures depend on the rate of stirring
of the mixtures and how finely crushed the ice is.

16.6 Materials Used for Heating Baths
Some materials that can be used for laboratory heating baths are given in Table16.9.

249

Laboratory Data and SI Units

Table16.9
Heating Bathsa
Medium
Water
Silicone oilb
Triethylene glycol
Glycerol
Dibutyl phthalate
Sand
Wood’s metalc

Mp (°C)

Bp (°C)

Useful Range
(°C)

Flash Point
(°C)

Comments

100

0–80

None

Ideal within a limited range

–60
–4
18

—
286
290

0–250
0–250
–20 to +260

~310
166
160

–35
—
70

340
—
—

150–320
> About 200
73–350

157
None
None

Noncorrosive
Water soluble, stable
Water soluble, nontoxic, viscous,
supercools
Viscous at low temperature
Ideal for high-temperature heating
Ideal for high-temperature heating

Source: Based on data in Gordon, A. J., and Ford, R. A., The Chemist’s Companion (New York: Wiley-Interscience,
1972), pp 449–450. Reprinted with permission of John Wiley & Sons, Inc.
a Experimental work with heating baths requires the use of efficient fume hoods and personal protection
equipment.
b Data for Dow Corning 550 silicone oil.
c 50% Bi, 25% Pb, 12.5% Sn, 12.5% Cd.

16.7 Drying Agents
Table16.10 gives a list of drying agents with their uses.
Table16.10
Drying Agents
Drying Agent
Alumina (Al2O3)
Barium oxide (BaO)
Calcium chloride (CaCl2)
Calcium hydride (CaH2)
Calcium oxide (CaO)
Calcium sulfate (CaSO4)
Lithium aluminium
hydride (LiAlH4)

Useful for

Comments

Hydrocarbons
Hydrocarbons, amines, alcohols,
aldehydes
Hydrocarbons, alkyl halides, ethers,
many esters
Hydrocarbons, ethers, amines, esters,
higher alcohols (>C4)
Low-boiling alcohols and amines,
ethers
Most organic substances
Hydrocarbons, aryl (not alkyl)
halides, ethers

Very high capacity; very fast; reactivated by heating
Slow but efficient; not suitable for compounds
sensitive to strong base
Not very efficient; good for predrying; not suitable
for most nitrogen and oxygen compounds
Not suitable for aldehydes and ketones

Magnesium sulfate
(MgSO4)
Molecular sieve 4Å

Most organic substances

Phosphorus pentoxide
(P2O5)
Potassium carbonate
(K2CO3)

Hydrocarbons, ethers, halides, esters,
nitriles
Alcohols, esters, nitriles, ketones

Nonpolar liquids and gases

Slow but efficient; not suitable for acidic compounds
Very fast and very efficient
Excess may be destroyed by slow addition of ethyl
acetate; predrying recommended; reacts with acidic
hydrogens and most functional groups
Very fast and very efficient; avoid using with very
acid-sensitive compounds
Very efficient; predrying with a common agent
recommended; can be reactivated by heating
Fast and efficient; predrying recommended; not
suitable for alcohols, amines, acids, ketones, etc.
Not suitable for acidic compounds
(continued on next page

250

Organic Chemist's Desk Reference, Second Edition

Table16.10 (continued)
Drying Agents
Drying Agent

Useful for

Comments

Potassium hydroxide
(KOH)
Silica gel

Amines (in inert solvents)

Sodium sulfate (Na2SO4)
Sulfuric acid (H2SO4)

Most organic substances
Saturated and aromatic hydrocarbons,
halides, inert neutral or acidic gases

Powerful; not suitable for acidic compounds;
pellets can corrode glassware
Very high capacity and very fast; can be reactivated
by heating
Inefficient and slow; good for gross predrying
Very high capacity; very fast, but use limited to
saturated or aromatic hydrocarbons

Hydrocarbons, amines

Source: This table is based on data in Gordon, A. J., and Ford, R. A., The Chemist’s Companion (New York: WileyInterscience, 1972), pp. 445–447. Reprinted with permission of John Wiley & Sons, Inc.

16.8 Pressure-Temperature Nomograph
The pressure-temperature nomograph for correcting boiling points to 760 mmHg (1 atm) is shown
in Figure16.1. It is used as follows. If the boiling point at nonatmospheric pressure (P mmHg) is
known, line up the values of the boiling point P in A and the pressure in C. The theoretical boiling
point at 760 mmHg can then be read off in B. Line up this figure in B with another pressure in C
and the approximate corresponding boiling point can be read off in A.

Pressure-Temperature Nomograph
Observed
A Boiling Point
AT P. MM
°C °F
400
700

300

600
500

200

400
300

100

200

Pressure 0
C “P” MM 0. .03
0 0

Boiling Point
Corrected
to 760 MM

°C °F
700
1200
600
1100
1000
500
900
800
400
700
600
300
500
400
200
300
100

0.0

. 4
0.0 05
0.0 6
0.1 8

0.2
0
0.4 .3

0.
0 6
1.0 .8

20
3
400
6
8 0
10 0
0
20
3000
500
700

100
0

Figure 16.1 Pressure-temperature nomograph.

10 8

3
4

To find a theoretical b.p. @ 760 mm:
1. Mark the observed boiling point on chart A
2. Mark the pressure on chart C
3. The line drawn from point A to C intersects
chart B to give the theoretical b.p. at 760 mm
To find an alternative b.p./pressure:
4. Line up point B figured in step 3 with
another pressure (chart C)
5. Extend the line BC through chart A to
approximate the corresponding b.p.

251

Laboratory Data and SI Units

16.9 SI Units
16.9.1 SI Base Units
The names and symbols of the seven SI base units are shown in Table16.11.
Table16.11
SI Base Units
Physical Quantity

Name of SI Base Unit

Symbol for SI Base Unit

Molea
Ampere
Metre
Candela
Kilogramb
Kelvin
Second

mol
A
m
cd
kg
K
s

Amount of substance
Electric current
Length
Luminous intensity
Mass
Themodynamic temperature
Time
a

The mole is the amount of substance of a system that contains as many elementary
entities as there are atoms in 0.012 kg of carbon-12. Although it is defined in terms
of the number of entities, in practice, 1 mol of atoms, molecules, or specific formula
units of a substance is measured by weighing M × (1 mol) of the substance, where
M is the molar mass, the mass per unit amount of substance. Molar mass is synonymous with the terms atomic weight, for atoms, and molecular weight, for molecules
or formula units, respectively, and is reported in grams per mole (g mol–1).
Among the base units of the SI system, the kilogram unit of mass is the only one
whose name, for historical reasons, contains a prefix (kilo-). Names and symbols for
multiples of the unit of mass are formed by attaching prefix names to the unit gram
and prefix symbols to the unit symbol g. For example, 10–6 kg = 1 mg (1 milligram)
but not 1µkg (1 microkilogram).

16.9.2 SI-Derived Units
The SI units for derived physical quantities are those coherently derived from the SI base units by
multiplication and division. Some of the SI-derived units that have special names and symbols are
presented in Table16.12.
Table16.12
Some SI-Derived Units
Physical Quantity

Name of SI Unit

Symbol for SI Unit

Definition of SI Unit

Electric charge
Energy
Force
Frequency
Potential difference
Power
Pressure

Coulomb
Joule
Newton
Hertz
Volt
Watt
Pascal

C
J
N
Hz
V
W
Pa

As
kg m2 s–2
kg m s–2 = J m–1
s–1
kg m2 s–3 A–1 = J A–1 s–1
kg m2 s–3 = J s–1
kg m–1 s–2 = N m–2

252

Organic Chemist's Desk Reference, Second Edition

16.9.3 Prefixes Used with SI Units
The prefixes listed in Table16.13 are used to indicate decimal multiples of base and derived SI units.
Table16.13
Multiplying Prefixes for Use with SI Units
Factor

Prefix
Deci
Centi
Milli
Micro
Nano
Pico
Femto
Atto
Zepto
Yocto

10
10–2
10–3
10–6
10–9
10–12
10–15
10–18
10–21
10–24
–1

Symbol
d
c
m
μ
n
p
f
a
z
y

Factor

Prefix

10
102
102
106
109
1012
1015
1018
1021
1024

Symbol

Deca (or deka)
Hecto
Kilo
Mega
Giga
Tera
Peta
Exa
Zetta
Yotta

da
h
k
M
G
T
P
E
Z
Y

16.9.4 Conversion Factors for Non-SI Units
Many non-SI units are now defined exactly in terms of SI; some can only be related to SI units via
fundamental constants, and the relationship is therefore restricted by the precision to which the
constants are known. Factors for converting some non-SI units into their SI equivalents are listed in
Table16.14. Names of units within the SI are indicated with an asterisk.
Table16.14
Conversion Factors for Non-SI Units
Unit
Ångström
Atmosphere
Atomic mass unit (unified)
Bar
* Becquerel (SI: activity (of a radioactive source))
Calorie (thermochemical)
* Coulomb (SI: electric charge)
Curie (radioactivity)
Debye
Degree Celsius
Degree Fahrenheit
Electronvolt
Hour
* Joule (SI: energy)
Kilowatt hour
Litre
Micron
Millimetre of mercury
Minute (time)

Symbol
Å
atm
u
bar
Bq
calth
C
Ci
D
°C
°F
eV
h
J
kW h
l, L
μ
mmHg
min

SI Equivalent
10–10
101,325
1.661

× 10–27
105
1

4.184
1
× 1010
× 10–30
1

3.7
3.336
5/9 (0.5556)
1.602
3,600

× 10–19
1

3.6

133.3
60

× 106
10–3
10–6

m
Pa
kg
Pa
s–1
J
As
Bq
Cm
K
K
J
s
Nm
J
m3
m
Pa
s

(continued on next page)

253

Laboratory Data and SI Units

Table16.14 (continued)
Conversion Factors for Non-SI Units
Unit

Symbol

SI Equivalent

* Newton (SI: force)

kg m s–2

* Ohm (SI: resistance)
* Pascal (SI: pressure)
* Sievert (SI: dose equivalent (of ionizing radiation))
Standard atmosphere
Ton (UK long, 2,240 lb)
Tonne (metric ton)
* Volt (SI: electric potential difference)

Ω
Pa
Sv
Atm
Ton
T
V

1
1
1
× 103
103
1

VA–1
N m–2
J kg–1
Pa
kg
kg
J C–1

* Watt (SI: power)

J s–1

101 325
1.016

* Names of units within the SI.

16.9.5 Conversion Factors for UK Imperial Units and Other Non-SI Units
of Measurement
Length
1 ångström unit (Å) = 10 –8 cm = 10 –10 m = 10 –1 nm
1 micron (μ) = 1 μm = 1–4 cm = 10 –6 m
A wavelength of n microns (n μm) = a wavenumber of 10,000/n cm–1
1 inch (in.) = 2.54 cm = 2.54 × 10 –2 m
1 metre = 39.3701 in.
Mass
453.592 g = 1 pound (lb)
1 kg = 2.20462 lb
Volume
1 mL (or 1 ml) = 1 cubic centimetre (cm3)
1 L (or 1 l) = 1 dm3 = 1 × 10 –3 m3 = 1000 mL (or 1000 ml)
1 litre = 2.12 pints (U.S.) = 1.76 pints (UK)
28.4 ml = 1 fluid ounce
Pressure
1 atm = 1.01325 × 105 pascal (N m–2)
= 101.325 kPa
= 760 torr = 760 mmHg
= 1.01325 bar
= 14.70 lb/in.2
1 mmHg (0ºC) = 1 torr = 1/760 atm

= 133.322 pascal

= 0.0193368 lb/in.2
1 kPa = 7.5006 mmHg
1 lb/in.2 = 51.715 mmHg

254

Organic Chemist's Desk Reference, Second Edition

Temperature
absolute zero (K) = –273.16°C
K = °C + 273.16
°F = (9 × °C)/5 + 32
°C = 5 (°F – 32)/9
Energy
1 joule = 1 watt s = 107 erg = 0.737561 ft lb
1 erg = 1 dyne cm = 1 g cm2 s–2
1 calorie = 4.1868 joule
1 electronvolt/molecule = 23.06 kcal mol–1

16.9.6 Further Reading on SI Units
Quantities, Units and Symbols in Physical Chemistry, 3rd ed. (Cambridge: IUPAC/Royal
Society of Chemistry, 2007).
McGlashan, M. L., Physicochemical Quantities and Units, 2nd ed., Royal Institute of
Chemistry Monographs for Teachers 15 (London: The Royal Institute of Chemistry, 1971).
Cardarelli, F., Encyclopaedia of Scientific Units, Weights and Measures: Their SI Equivalences
and Origins (London: Springer, 2003).
16.9.6.1 Websites
Bureau International des Poids et Mesures: http://www.bipm.org/en/home/
National Institute of Standards and Technology (U.S.): http://physics.nist.gov/cuu/Units/units.html
National Physical Laboratory (UK): http://www.npl.co.uk/reference/measurement-units/

17 Languages
The best dictionaries for chemists are:
Patterson, A. M., German-English Dictionary for Chemists (Chichester: Wiley).
Patterson, A. M., French-English Dictionary for Chemists (Chichester: Wiley).
Dictionary of Chemical Terminology in Five Languages (Amsterdam: Elsevier, 1980) (covers
English, German, French, Polish, and Russian).

17.1 A German-English Dictionary
Note that the correct form of many German words ending in ss is to use the symbol ß, e.g., Blaß,
Heiß. Since this symbol is frequently not available on keyboards and complicates indexing, it is
becoming less frequent, but will still often be found in books and journals.
For keyboards without an umlaut, or where it is desired to avoid the use of the umlaut, the correct
transliteration is to insert a following e, e.g., Tröger’s base → Troeger’s base.
Abbau
abdestillieren
aber
abfiltrieren
abgeben
abkühlen
agnehmend
Abscheidung
abtrennen
Abtrennung
Abweichung
acht
ähnlich
Alkylierung
allgemein
allmählich
als
alt
Ameisensäure
ander
ändern
anders
anfänglich
anfangs
angesäuert

decomposition, degradation
to distil off
but, however
to filter off
to give off
to cool down
decreasing
separation
to separate
separation
deviation, variation
eight
similar
alkylation
generally
gradual(ly)
as, then
old
formic acid
other, another
to change
otherwise, differently
at first
at first
acidified

Angriff
Anlagerung
annähernd
ansäuern
anstelle
Anteil
Anwendung
Anwesenheit
Äpfelsäure
Äthanol
Äther
äthyl
auch
Aufarbeitung
auffangen
auflösen
Aufnahme
aus
Ausbeute
audfällen
ausführen
Ausgangsmaterial
ausgenommen
ausgescheiden
Ausscheidung

attack
addition, approach
approximate
to acidify
instead
constituent
use
presence
malic acid
ethanol
ether
ethyl
also
work up
to collect
to dissolve
absorption
out of, from
yield
to precipitate
to carry out
starting material
except
separated
separation

255

256

Organic Chemist's Desk Reference, Second Edition

Ausschluss
ausser
ausserdem

exclusion
except, besides
besides, moreover

Bad
basisch
Bedeutung
behandeln
Beispiel
bekannt
Belichtung
Benzin
Benzol
beobachten
Berechnet
bereiten
bereits
Bernsteinsäure
beschleunigen
beschreiben
besonders
besser
beständig
Bestandteil
bestehen
bestimmen
Bestimmung
Bestrahlung
Beugung
beweisen
bilden
bildung
bindung
bis
blass
Blatt
Blättchen
blau
bläulich
Blausäure
Blei
Bor
brauchbar
Braun
bräunlich
Brechung
Breite
brennen
Brenztraubensäure

bath
basic
meaning, significance
to treat
example
known
exposure to light
petroleum ether
benzene
to observe
calculated
to prepare
already
succinic acid
to accelerate
to describe
especially
better
stable
constituent
to consist, to exist
to determine
determination
irradiation
diffraction
to prove
to form
formation
bond
until
pale
leaf
leaflet
blue
bluish
hydrocyanic acid
lead
boron
useful
brown
brownish
refraction
width
to burn
pyruvic acid

Brom
Bromierung
Brücke
Buttersäure

bromine
bromination
bridge
butyric acid

Chinolin
Chinon
Chlor
Chlorierung
Chlorwasserstoff

quinoline
quinone
chlorine
chlorination
hydrogen chloride

dagegen
Dampf
danach
daneben
darin
Darstellung
dass
Dehydratisireung
Dehydrierung
Derivat
desgleichen
destillieren
Destillierung
deutlich
dick
dies
diese
digerieren
doppelt
drei
dreifach
dreissig
Druck
dunkel
dünn
durch
durchführen

on the other hand
vapour
after that
besides
therein, in it
preparation
that
dehydration
dehydrogenation
derivative
likewise
to distil
distillation
clear
thick
this
this, these
to digest
double
three
triple
thirty
pressure
dark
thin
through, by
to carry out

ebenfalls
Eigenschaft
Ein
einbringen
eindampfen
eindeutig
einengen
einfach
einiger
Einkristall

likewise
property
one
to introduce
to evaporate
unequivocal
to concentrate
simple
some, several
single crystal

257

Languages
einleiten
einmal
Einschluss
einstündig
eintägig
eintropfen
einzig
Eis
Eisen
Eisessig
elf
eluieren
Enolisierung
entfernen
entgegen
enthalten
entsprechend
entstehen
Entwässerung
Entwicklung
Entzündung
erfolgen
erforderlich
ergeben
Ergebnis
ergibt
erhalten
erhitzen
Erhöhung
erscheinen
erst
Erstarrung
erste
erwärmen
erzielen
Essigsäure

to introduce
once
inclusion
for one hour
for one day
to add dropwise
only
ice
iron
glacial acetic acid
eleven
to elute
enolisation
to remove
against
to contain
corresponding
to originate
dehydration
evolution
ignition
to occur
necessary
to yield
result
yields
to obtain
to heat
increase
to appear
first, only
solidification
first
to warm
to obtain
acetic acid

fällen
falsch
Farbe
farbig
farblos
Farbstoff
Farbumschlag
fast
fein
Feld
ferner
fest

to precipitate
incorrect
colour
coloured
colourless
dyestuff
colour change
almost
fine
field
further
solid

Feststoff
Feuchtigkeit
Flammpunkt
flüchtig
flüssig
Flüssigkeit
Folge
folgen
Formel
Fortschritt
frei
frisch
früher
führen
fünf

solid
moisture
flash point
volatile
liquid
liquid
sequence, series
to follow
formula
progress
free
fresh
former(ly)
to lead
five

ganz
Gärung
gasförmig
geben
gebräuchlich
gebunden
geeignet
gefällt
gefärbt
Gefäss
gegen
Gegenwart
Gehalt
gekocht
gekühlt
gelb
gelblich
gelöst
Gemisch
gemischt
genau
gepuffert
gering
geringer
Geruch
gerührt
gesättigt
geschmolzen
Geschwindigkeit
getrennt
getrocknet
Gewicht
gewinnen

whole
fermentation
gaseous
to give
usual
bonded
suitable
precipitated
coloured
vessel
against
presence
contents
boiled
cooled
yellow
yellowish
dissolved
mixture
mixed
exact
buffered
small
minor
odour
stirred
saturated
fused, molten
rate
separated
dried
weight
to obtain

258

Organic Chemist's Desk Reference, Second Edition

gewiss
gewogen
gewöhnlich
gibt
giftig
Gitter
gleich
gleichfalls
Gleichgewicht
Gleichung
gleichzeitig
gliedrig
grau
Grenze
gross
grün
Gruppe

certainly
weighed
usual
gives
poisonous, toxic
lattice
equal
likewise
equilibrium
equation
simultaneously
membered
grey
limit
great, large
green
group

halb
Halogenierung
haltbar
Harnstoff
Hauptprodukt
heftig
heiss
hell
hemmen
Herkunft
herstellen
Herstellung
Hilfe
hingegen
hinzufügen
Hitze
hoch
hohe
hundert
Hydratisierung
Hydrierung

half
halogenation
stable
urea
main product
violently
hot
light, pale
to inhibit
origin
to produce
production
help
on the contrary
to add
heat
high
high
hundred
hydration
hydrogenation

immer
induziert
Inhalt
insgesamt
Isolierung

always
induced
contents
altogether
isolation

Jahr
je nach
jedoch

year
according to
however

Jod
Jodierung
Kalium
kalt
katalytisch
kein
Kern
Kette
klar
klein
kochen
Kochpunkt (Kp)
Kohlensäure
Kohlenstoff
Kohlenwasserstoff
kondensieren
konjugiert
konzentriert (konz.)
Kopplung
Kraft
Kühlen
kühlung
Kupfer
kurz

iodine
iodination
potassium
cold
catalytic
no, not a
nucleus
chain
clear
small
to boil
boiling point (bp)
carbon dioxide, carbonic acid
carbon
hydrocarbon
to condense
conjugated
concentrated (conc.)
coupling
force
to cool
cooling
copper
short

Ladung
lang
langsam
lassen
leicht
leiten
letzte
Licht
liefern
links
lösen
löslich
Löslichkeit
Lösung
Lösungsmittel
Luft

charge
long
slow(ly)
to leave
easy, easily
to conduct
last
light
to yield
left
to dissolve
soluble
solubility
solution
solvent
air

mässig
mehr
mehrere
mehrfach
mehrmals
mehrstündig
meist

moderately
more
several
multiple
several times
for several hours
most

259

Languages
Menge
Messung
Milchsäure
mischbar
Mischbarkeit
mischen
Mischung
mit
mittels
möglich
Molverhältnis
müssen
Mutterlauge

amount
measurement
lactic acid
miscible
miscibility
to mix
mixture
with
by means of
possible
molar ratio
must
mother liquor

nach
nachfolgend
nachstehend
Nacht
Nachweis
Nadel
nahe
nämlich
Natrium
neben
Nebenprodukt
neun
Niederschlag
niedrig
niemals
Nitrierung
noch
nochmalig
notwendig
nunmehr
nur

after
subsequent
following
night
proof, detection
needle
near
namely
sodium
beside, in addition to
by-product
nine
precipitate
low
never
nitration
still, yet
repeated
necessary
now
only

oben
Oberfläche
oberhalb
oder
offen
offenbar
ohne
Öl
ölig
Ölsäure

above
surface
above
or
open
obvious
without
oil
oily
oleic acid

Phosphor
primär

phosphorus
primary

protoniert
Puffer
Pulver
Punkt

protonated
buffer
powder
point

Quecksilber

mercury

rasch
Raum
rechts
Reihe
rein
Reinheit
Reinigung
restlich
richtig
Rohprodukt
rosa
rot
rötlich
Rückfluss
Rückgewinnung
Rückstand
rühren

rapid
space, room
right
series
pure
purity
purification
residual
correct
crude product
pink
red
reddish
reflux
recovery
residue
to stir

Salpetersäure
Salz
Salzsäure
sättigen
sauer
Sauerstoff
Säure
Schall
scheiden
scheinbar
schlecht
schliessen
schliesslich
schmelzen
Schmelzpunkt (Schmp)
schnell
schon
schütteln
Schutzgas
schwach
schwarz
Schwefel
Schwefelsäure
schwer

nitric acid
salt
hydrochloride acid
to saturate
acidic
oxygen
acid
sound
to separate
apparently
poor
to close
finally
to melt
melting point (mp)
fast, quickly
already
to shake
inert gas
weak
black
sulfur
sulfuric acid
heavy, difficult

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Organic Chemist's Desk Reference, Second Edition

Schwingung
sechs
sehr
Seitenkette
sieben
sieden
siedend
Siedepunkt
Silizium
sofort
sonst
sorgfältig
Spaltung
Spiegel
Stäbchen
stark
starr
statt
stattfinden
stehen
stehen lassen
Stellung
Stickstoff
Stoff
Stoffwechsel
Stoss
Strahlung
streuen
Stufe
Stunde
substituiert

vibration
six
very
side chain
seven
to boil
boiling
boiling point
silicon
immediately
otherwise, else
carefully
cleavage, scission
mirror
small rod
strong
rigid
instead of
to take place
to stand
to leave standing
position
nitrogen
substance
metabolism
substance
radiation
to scatter
step, stage
hour
substituted

Tafel
Täfelchen
Tag
Teil
Teilchen
teilweise
tief
toluol
trennen
Trennung
trocken
trocknen
Tropfen

plate
platelet
day
part
particle
partially
deep
toluene
to separate
separation
dry
to dry
drop

über
Übergang

over, above
transition

Überschluss
überwiegend
üblich
übrig
Umesterung
Umkristallisierung
Umlagerung
Umsatz
Umsetzung
Umwandlung
unbeständig
unkorrigiert
unlöslich
unrein
unten
unter
Untersuchung
ursprünglich

excess
predominantly
usual
remaining
transesterification
recrystallisation
rearrangement
exchange
reaction
conversion
unstable
uncorrected
insoluble
impure
below, underneath
under
investigation
original

Verbindung
Verbrennung
Verdampfung
verdünnt (verd.)
vereinigen
Veresterung
Verfahren
verfärben
Vergärung
Vergleich
vergleichen
Verhalten
Verhältnis
Verlauf
vermindern
vermischen
verrühren
Verschiebung
Verseifung
versetzen
Versuch
verwandt
Verwendung
verzweigt
viel
vieleicht
vier
voll
vom

compound
combustion
evaporation, vaporisation
dilute (dil.)
to combine
esterification
procedure
to change colour
fermentation
comparison
to compare
behaviour
proportion, ratio
course, progress
to diminish, to reduce
to mix
to stir up
shift
saponification
to add, mix
experiment
related
use
branched
much, many
perhaps, possibly
four
full
of the, from the

261

Languages
vor allem
Vorbehandlung
Vorkommen
Vorsicht
vorsichtig
vorwiegend

above all
pretreatment
occurrence
caution, care
cautious(ly)
predominant

wahrscheinlich
waschen
Wasser
Wasserdampf
wasserfrei
wasserhaltig
wässerig
Wasserstoff
wässrig
Weg
wegen
Weinsäure
weiss
weiter
Welle
Wellenlänge
wenig
werden
Wertigkeit
wesentlich
wichtig
wiederholt
Winkel
wird
Wirkung
Wismut
Woche

probable, probably
to wash
water
water vapour, steam
anhydrous
hydrated or wet
aqueous
hydrogen
aqueous
route
on account of
tartaric acid
white
additional
wave
wavelength
little, few
to become
valency
essential
important
repeated(ly)
angle
becomes, is
action, effect
bismuth
week

zehn
Zeit
Zeitschrift
zerfliesslich
zersetzen
zersetzlich
Zersetsung (Zers.)
ziegelrot
Zimmer
Zimtsäure
Zinn
Zucker
zuerst
zufügen
Zugabe
zugebeu
zugleich
zuletzt
zum Beispiel (z.B.)
Zunahme
zur
zurückbleiben
zusammen
zusäzlich
Zustand
zutropfen
zuvor
zwanzig
zwecks
zwei
zweimal
zwischen
Zwischenprodukt
zwölf

ten
time
periodical, journal
deliquescent
to decompose
unstable
decomposition (dec.)
brick red
room
cinnamic acid
tin
sugar
at first
to add
addition
to add
at the same time, together
at last, finally
for example (e.g.)
increase
to the
to remain behind
together
additional
state, condition
to add drop by drop
before, previously
twenty
for the purpose of
two
twice
between
intermediate
twelve

17.2 Russian and Greek Alphabets
The Russian and Greek alphabets, with their capitals, small letters, and English equivalents, are
shown in Table17.1.
Most chemical names in Russian are very similar to their Western equivalents, once transliteration from the Cyrillic alphabet has been applied.
For example:
Пиридин
Тестостерон
2-Аллил-2-метил-1,3-циклопентандиол
6-метокси-2-пропионилнафталин

Pyridine
Testosterone
2 Allyl-2 methyl-1,3-cyclopentanediol
6-Methoxy-2-propionylnaphthalene

262

Organic Chemist's Desk Reference, Second Edition

Table17.1
Greek

Αα
Ββ
Γγ
Δδ
Εε
Ζζ
Ηη
Θθ
Ι ι
Κκ
Λλ
Μμ
Νν
Ξξ
Οο
Ππ
Ρρ
Σσς
Ττ
Υυ
Φφ
Χχ
Ψψ
Ωω

alpha
beta
gamma
delta
epsilon
zeta
eta
theta
iota
kappa
lambda
mu
nu
xi
omicron
pi
rho
sigma
tau
upsilon
phi
chi
psi
omega

Russian

a
b
g, n
d
e
z
ē
th
i
k
l
m
n
x
o
p
r, rh
s
t
y, u
ph
ch
ps
ō

Аа
Бб
Вв
Гг
Дд
Ее
Жж
Зз
ИиЙй
Кк
Лл
Мм
Нн
Оо
Пп
Рр
Сс
Тт
Уу
Фф
Хх
Цц
Чч
Шш
Щщ
*Ъ ъ
Ыы
*Ь ь
Ээ
Юю
Яя

a
b
v
g
d
e
zh
z
i, ĭ
k
l
m
n
o
p
r
s
t
u
f
kj
ts
ch
sh
shch
y
e
yu
ya

* Characters that have no sound themselves but alter the pronunciation of the preceding consonant.