Steroids are biologically active organic compounds with four fused rings that make up their core structure, typically composed of seventeen carbon atoms. Sterols are a form of steroid that contain a hydroxy group at position three and are derived from cholestane. Gonane, the parent structure of steroids, theoretically has 64 possible stereoisomers due to its six centers of chirality, with 5α-gonane and 5β-gonane being the most common.

1. STEROIDS
DR. NUTAN RAO

2. INTRODUCTION
• A steroid is a biologically active organic
compound with four rings arranged in a
specific molecular configuration.
• The steroid core structure is typically composed of
seventeen carbon atoms, bonded in four "fused" rings:
three six-member cyclohexane rings (rings A, B and C in
the first illustration) and one five-
member cyclopentane ring (the D ring).
• Sterols are forms of steroids with a hydroxy group at
position three and a skeleton derived from cholestane.

3. GONANE OR CYCLOPENTANOPERHYDROPHENANTHRENE
Because gonane has six centers of chirality, it has 64
(26) theoretically possible stereoisomers.
The most common stereoisomers of gonane are 5α-
gonane and 5β-gonane.

4. 5α-Gonane 5β-Gonane