JEE Main 2022 · 24 June · evening · Single correct · +4 / −1
The structure shown below is of which well-known drug molecule?
- (a) Ranitidine
- (b) Seldane
- (c) Cimetidine
- (d) Codeine
Answer and solution
Answer (c) Cimetidine
Solution
Chemistry ma’am · 3 steps
Spot the imidazole ring and the cyanoguanidine end: those two pieces together say cimetidine.
- Read the ring. On the right is a five-membered ring with two nitrogens, one of them N–H. That is an imidazole ring carrying a methyl group, the same ring that histamine has.
- Read the chain. A -CH₂-S-CH₂CH₂-NH⁻ chain joins the ring to a guanidine unit, C(=N-C≡N)NHCH₃. The -C≡N on the imine nitrogen makes this a cyanoguanidine group.
Drug Type Key structural feature Ranitidine Antacid (H₂ blocker) furan ring and a -NO₂ group on the chain Seldane (terfenadine) Antihistamine piperidine ring with several benzene rings, no sulphur chain Cimetidine Antacid (H₂ blocker) imidazole ring, -CH₂SCH₂CH₂⁻ chain, cyanoguanidine Codeine Narcotic analgesic fused multi-ring (morphine-type) skeleton - So. The structure is cimetidine, option (c). It was designed to look like histamine so it could block the H₂ receptors in the stomach and cut down acid release.
The idea to keep. Cimetidine and ranitidine share the -CH₂SCH₂CH₂⁻ chain. Tell them apart by the ring: imidazole means cimetidine, furan means ranitidine.
Answer from the NTA final answer key. Solution by PrepWiser.