Question

Steroidal cholestane ring fused with

• A. 5, 6, 7, 9, 10, 13
• B. 5, 6, 8, 9, 10, 11
• C. 5, 6, 8, 9, 10, 13
• D. 5, 6, 8, 9, 10, 14

Hint:

Remember the tetracyclic steroid nucleus involves key fusion points at carbons 5, 6, 8, 9, 10, and 13 — important for structural identification in medicinal chemistry.

Answer 1

The Correct Option is C

- Cholestane is a saturated derivative of cholesterol and serves as the parent compound for many steroids.
- It consists of a perhydrocyclopentanophenanthrene nucleus, which includes three six-membered rings (A, B, and C) and one five-membered ring (D).
- These four rings are fused together at the carbon positions 5, 6, 8, 9, 10, and 13, forming a tetracyclic skeleton.
- This numbering follows IUPAC nomenclature, and these positions are critical for defining stereochemistry and biological activity of steroid molecules.