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Provisional Recommendations

Chemical Nomenclature and Structure Representation Division

 

Nomenclature of Organic Chemistry

For nomenclature purposes, a structure containing at least one carbon atom is considered to be an organic compound. The formation of a systematic name for an organic compound requires selection and then naming of a parent structure. This basic name may then be modified by prefixes, infixes, and, in the case of a parent hydride, suffixes, which convey precisely the structural changes required to generate the compound in question from the parent structure. In contrast to such systematic names, there are traditional names which are widely used in industry and academic circles. Examples are acetic acid, benzene and pyridine. Therefore, when they meet the requirements of utility and when they fit into the general pattern of systematic nomenclature, these traditional names are retained.

A major new principle is elaborated in these Recommendations. The concept of ‘preferred IUPAC names’ is developed and systematically applied. Up to now, the nomenclature developed and recommended by IUPAC has emphasized the generation of unambiguous names in accord with the historical development of the subject. In 1993, due to the explosion in the circulation of information and the globalization of human activities, it was deemed necessary to have a common language that will prove important in legal situations, with manifestations in patents, export-import regulations, environmental and health and safety information, etc. However, rather than recommend only a single ‘unique name’ for each structure, we have developed rules for assigning ‘preferred IUPAC names’, while continuing to allow alternatives in order to preserve the diversity and adaptability of the nomenclature to daily activities in chemistry and in science in general.

Thus, the existence of preferred IUPAC names does not prevent the use of other names to take into account a specific context or to emphasize structural features common to a series of compounds. Preferred IUPAC names belong to ‘preferred IUPAC nomenclature’ Any name other than a preferred IUPAC name, as long as it is unambiguous and follows the principles of the IUPAC recommendations herein, is acceptable as a ‘general’ IUPAC name, in the context of ‘general’ IUPAC nomenclature. The concept of preferred IUPAC names is developed as a contribution to the continuing evolution of the IUPAC nomenclature of organic compounds. This book (Recommendations 2004) covers and extends the principles, rules and conventions described in two former publications: Nomenclature of Organic Chemistry, 1979 Edition and A Guide to IUPAC Nomenclature of Organic Compounds, Recommendations 1993. In a few instances, the 1979 rules and the 1993 recommendations have been modified to achieve consistency within the entire system. In case of divergence among the various recommendations, Recommendations 2004 prevail.

> Download full text of the Provisional Recommendations from the CONTENTS below. Alternatively, and to facilitate full text searching, the whole volume as single pdf is also available [pdf - 10.34MB].

In addition, a file compiling the changes made in this new edition and compare to the 1979 edition and the 1993 Guide is also available [pdf - 96KB].

Comments by 31 March 2005

To Prof. Henri A. Favre
2031 Rue Leclaire
Montréal, QC H1V 3A1
Canada

TEL: +1 514 259 7963
E-MAIL: halfa@contact.net

  and to Dr. Warren H. Powell
1436 Havencrest Court
Columbus, OH 43220-3841
USA

TEL: +1 614 451 1830
E-MAIL: wpowell2@juno.com

 

CONTENTS

CHAPTER P-1 NOMENCLATURE OF ORGANIC COMPOUNDS [pdf - 936KB]

P-10 Introduction
P-11 Scope of nomenclature of organic compounds
P-12 Preferred, preselected and retained names
P-13 Operations in nomenclature
P-14 General rules
P-15 Types of nomenclature
P-16 Name writing

CHAPTER P-2 PARENT HYDRIDES

P-20 Introduction [P-20 to P-24, pdf - 558KB]
P-21 Mononuclear and polynuclear acyclic parent hydrides
P-22 Monocyclic hydrides
P-23 Polyalicyclic (von Baeyer) systems
P-24 Spiro compounds
P-25 Fused and bridged fused systems [pdf - 727KB]
P-26 Phane nomenclature [P-26 to P-29, pdf - 636KB]
P-27 Fullerenes
P-28 Ring assemblies
P-29 Prefixes denoting substituent groups derived from parent hydrides

CHAPTER P-3 CHARACTERISTIC (FUNCTIONAL) GROUPS [pdf - 441KB]

P-30 Introduction
P-31 Modification of the degree of hydrogenation of parent hydrides
P-32 Prefixes for substituent groups derived from parent hydrides with a modified degree of hydrogenation
P-33 Suffixes
P-34 Parent structures other than parent hydrides and corresponding prefixes for substituent groups
P-35 Prefixes denoting characteristic groups

CHAPTER P-4 RULES FOR NAME CONSTRUCTION [pdf - 710KB]

P-40 Introduction
P-41 Seniority order of classes
P-42 Seniority order of acids
P-43 Seniority order of suffixes
P-44 Seniority order of parent structures
P-45 The principal chain in substituent groups
P-46 Substitution rules for parent structures with retained names

CHAPTER P-5 CONSTRUCTING PREFERRED IUPAC NAMES [pdf - 523KB]

P-50 Introduction
P-51 Selecting the preferred type of nomenclature
P-52 Selecting preferred IUPAC names and preselected names (see P-12) for parent hydrides names
P-53 Selecting the preferred method for modifying the degree of hydrogenation for parent hydrides
P-54 Selecting the preferred suffix (principal group)
P-55 Selecting preferred retained names
P-56 Selecting preferred substituent group names
P-57 Selecting preferred names for tautomeric compounds
P-58 Name construction

CHAPTER P-6 APPLICATIONS TO SPECIFIC CLASSES OF COMPOUNDS

P-60 Introduction [P-60 to P-64, pdf - 666KB]
P-61 Substitutive nomenclature: prefix mode
P-62 Amines and imines
P-63 Hydroxy compounds, ethers, peroxols, peroxides and chalcogen analogues
P-64 Ketones, pseudo ketones and heterones, and chalcogen analogues
P-65 Acids and derivatives [pdf - 613KB]
P-66 Amides, hydrazides, nitriles, aldehydes [pdf - 561KB]
P-67 Oxoacids used as parents for organic compounds [pdf - 365KB]
P-68 Nomenclature of other classes of compounds [pdf - 524KB]
P-69 Organometallic compounds [pdf - 153KB]

CHAPTER P-7 RADICALS, IONS, AND RELATED SPECIES [pdf - 655KB]

P-70 General methodology
P-71 Radicals
P-72 Anions
P-73 Cations
P-74 Zwitterions
P-75 Radicals ions
P-76 Delocalized radicals and ions
P-77 Preferred names

CHAPTER P-8 ISOTOPICALLY MODIFIED COMPOUNDS [pdf - 194KB]

P-80 Introduction
P-81 Symbols and definitions
P-82 Isotopically substituted compounds
P-83 Isotopically labelled compounds
P-84 Comparative examples of formulae and names of isotopically modified compounds

CHAPTER P-9 SPECIFICATION OF CONFIGURATION AND CONFORMATION [pdf - 905KB]

P-90 Introduction
P-91 CIP Priority and sequence rules
P-92 Configurational stereodescriptors
P-93 Applications of stereodescriptors
P-94 Conformation and conformational stereodescriptors

CHAPTER P-10 PARENT STRUCTURES FOR NATURAL PRODUCTS AND RELATED COMPOUNDS [pdf - 1.05MB]

P-100 Introduction
P-101 Nomenclature for natural products based on parent hydrides (alkaloids, steroids, terpenes, carotenes, corrinoids, tetrapyrroles, and similar compounds)
P-102 Carbohydrate nomenclature
P-103 Amino acids and peptides
P-104 Cyclitols
P-105 Nucleosides
P-106 Nucleotides
P-107 Lipids

REFERENCES [pdf - 37KB]

APPENDIX 1 [pdf - 18KB]
Seniority list of elements and 'a' terms used in replacement ('a') nomenclature in decreasing order of seniority

APPENDIX 2 [pdf - 308KB]
Usual detachable prefixes used in substitutive nomenclature

 

> 'Preferred names' Project Description


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