Nomenclature of Steroids: Rules and Examples

1. STEROIDS:
NOMENCLATURE
DR. JASMINE (ASSOCIATE PROF.)
MMCP, MM(DU), MULLANA

2.  Steroids are group of cyclic organic compounds
containing 4 rings fused together.
 Ring A, B and C are 6-membered while Ring D is 5-
membered.
 These are modified triterpenes which are derived from
squalene by cyclization, unsaturation and substitution.
 The nucleus of all steroids is tetracyclic C17
hydrocarbon 1,2-cyclopentanoperhydrophenanthrene
which may be substituted by methyl groups at C10
and C13, as well as an alkyl side-chain at C17.

4.  Steroids are widely distributed in plants, animals,
fungi etc. and serve various pharmacological functions
like
 Sex hormones: Estrogen, progesterone and testosterone
 Anti-inflammatory: Cortisone
 Diuretic: Spironolactone
 Antibiotic: Fusidic acid

5. NOMENCLATURE
1. Nearly all steroids contain one of the following steroidal ring

6.  Solid lines denote group above plane of nucleus and
represented by β-configuration.
 Dotted or broken lines denote group below the plane
of nucleus and represented by alpha (α)
configuration.
 If configuration of substituent is unknown, it is
represented as wavy line.
 Circles are also used sometimes to indicate α-
hydrogen and dark dots (.) to indicate β-hydrogen.
3β-hydroxy 3α- hydroxy

7.  Symbol delta (▲) is used to designate C=C bond in a
steroid. E.g. If = bond is between C-4 and C-5, it can be
written as ▲ 4
 If = bond is not between sequential no. of carbon, in
such cases, both carbons are indicated in name. e.g +
bond is between C5 and C10, it will be written as ▲5(10)
▲ 2- Gonene/ Gon-2-ene ▲5(10)-Gonene/ Gon-5(10)-ene

8.  When methyl group is missing from side chain, it is
indicated by prefix ‘Nor’ with no. of C-atom which has
disappear.
19-Norandrostane

9. EXAMPLES FOR PRACTICE
▲ 5- Androstene/ Androst-5-ene ▲1,3,5(10)- Estren-3α, 17β-diol/
Estra-1,3,5(10)-triene- 3α, 17β-diol
17β-hydroxyandrost-4-en-3-one
(Testosterone)

10. 17α-methyl-4β, 17 β-dihydroxyandrost-4-en-3-one
19Norandrost-3-one
9 α-fluoro-17α-ethyl-11β, 17 β-dihydroxyandrost-4-en-3-one

11. Pregn-4-en-3 β,20β-dione (Progesterone) Cholest-5-en-3-ol/ Cholesterol
11 β, 17α, 21β-trihydroxypregn-4-en-3 β,20 β –dione (Hydrocortisone)