IUPAC-IUB Joint Commission on Biochemical Nomenclature

The Nomenclature of Steroids
Recommendations 1989

Contents and Introduction



References for this section



3S-1. General

1.0 Definition of steroids and sterols
1.1 Numbering and ring letters
1.2 Absent carbon atoms
1.3 Absolute configuration
1.4 Orientation of projection formulae
1.5 Stereochemistry of ring junctions and side-chain attachment
1.6 Stereochemistry of substituents in the side chain
3S-2. Fundamental carbocycles, unsaturation and alkyl substitution at C-17
2.1 Gonane
2.2 Estrane (oestrane)
2.3 Androstane
2.4 Parent hydrocarbons with side chain at C-17
2.5 Unsaturation
2.6 Stereochemistry of double bonds
2.7 Steroids with a side chain as part of the parent carbocycle and an alkylsubstituent at C-17
2.8 Steroids with two alkyl substituents at C-17
2.9 Replacement of carbon atoms by hetero atoms
2.10 Additional rings formed within the steroid skeleton
3S-3. Steroids with heterocyclic rings in the side chain
3.0 General definitions
3.1 Cardanolides
3.2 Bufanolides
3.3 Spirostans
3.4 Furostans
3.5 Steroid alkaloids
3S-4. Functional groups
4.0 General
4.1 Acids, salts and esters
4.2 Lactones
4.3 Esters of sterols and steroid alcohols
4.4 Oxo compounds
4.5 Alcohols
4.6 Amines
4.7 Ethers
4.8 Acetals and ketals
4.9 Trivial names of important steroids
4.10 Use of international non-proprietary names
3S-5. Stereochemical modifications
5.1 Use of the prefix ent-
5.2 Use of [alpha] and [beta] for bridgeheads
5.3 Use of [alpha]/[beta] and ent-
5.4 Use of the prefix rac-
5.5 Use of R* and S*
3S-6. Lengthening and shortening of side chains and elimination of methylgroups
6.1 Use of the prefix homo-
6.2 Use of the prefix nor-
6.3 Preference between homo- and nor-
3S-7. Ring contraction and expansion
7.1 Use of the prefix nor-
7.2 Use of the prefix des-
7.3 Use of the prefix homo-
7.4 Use of both nor- and homo- in one name
7.5 Use of the prefix abeo-
3S-8. Ring fission
8.1 Use of the prefix seco-
8.2 Use of [alpha] and [beta] in seco-compounds
3S-9. Vitamin D group
9.0 General
9.1 Trivial names
9.2 Modifications of the triene system
9.3 Modification of the side chain
9.4 Additional hydroxyl groups
3S-10. Additional rings
10.0 General
10.1 Bridged steroids
10.2 Additional ring(s) fused to a steroid
10.3 Spiro union with a steroid
Appendix Selected international non-proprietary names (INNs) for steroids

Addendum. Numbering of Steroid Side-chain Atoms


The recommendations of steroid nomenclature have a long history, a brief account of which was given in definitive rules for the nomenclature of steroids (1971) [1]. Since that time, many of the principles developed for the nomenclature of steroids have been generally adopted and have become part of the IUPAC nomenclature of organic compounds, especially section F [3]. The aim of the present document, prepared with the help of a panel of experts, is a revision of the recommendations in the light of new developments and current practice.

The main changes are as follows: (i) modifications, where appropriate, to conform to section F (Natural Products) of the IUPAC nomenclature [3]; (ii) a wider use of the R,S system for designating the stereochemistry in the side chain; (iii) the incorporation of the new recommendations (1981) for the nomenclature of vitamin D [5]; and (iv) the omission of most steroid alkaloid and steroid-like triterpenoids as it is intended that they should be treated in an appendix to IUPAC nomenclature, section F [3].

These recommendations are numbered 3S-1, 3S-2, 3S-3, etc., the initial 3 denoting that this is the third revised set of recommendations.


1. IUPAC Commission on the Nomenclature of Organic Chemistry (CNOC) andIUPAC-IUB Commission on Biochemical Nomenclature (CBN). The Nomenclature of Steroids, Revised tentative rules, 1967. Arch. Biochem. Biophys.136, 13-35 (1970), amended 147, 4-7 (1971); Biochem. J. 113, 5-28 (1969), amended 127, 613-616 (1972); Biochemistry, 8, 2227-2242 (1969), amended 10, 4994-4995 (1971); Biochim. Biophys. Acta, 164, 453-486 (1968), amended 248, 387-390 (1971); Eur. J. Biochem. 10, 1-19 (1969), amended 25, 1-3 (1972); Pure Appl. Chem. 31, 285-322 (1972), with amendments incorporated; also pp. 133-153 of [2], with amendments included.

2. International Union of Biochemistry (1978) Biochemical nomenclature and related documents, The Biochemical Society, London.

3. International Union of Pure and Applied Chemistry, Nomenclature of organic chemistry, Sections A, B, C, D, E, F and H, 1979 Edition, Pergamon Press, Oxford, 1979. Section E appeared also in pp. 1-18 of [2], and section F in pp. 19-26 of [2] and in Eur. J. Biochem. 86, 1-8 (1978).

5. IUPAC-IUB Joint Commission on Biochemical Nomenclature (JCBN), Nomenclature of vitamin D. Recommendations 1981. Arch. Biochem. Biophys. 218, 342-346 (1982); Endokrinol. Inform. 1982(2), 53-62; Eur.J. Biochem. 124, 223-227 (1982); Mol. Cell. Biochem. 49, 177-181 (1982); Pure Appl. Chem. 54, 1511-1516(1982).

Continued in 3S-1 general.

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