A new route to steroid ring-c aromatization from 7-oxygenated steroids

Abstract

3β-Acetoxy-5α-cholesta-8,14-dien-7β-ol (3), 3β-acetoxy-8α,9α-epoxy-5α-cholestan-7β-ol (6a), and 3β-acetoxy-8α, 14α-epoxy-5α-cholestan-7β-ol (8a) have been aromatized with hydrochloric acid in ethanol to afford a 9 : 1 mixture of 12-methyl-18-nor-5α,17β(H)-cholesta-8,11,13-trien-3β-ol (4) and 12-methyl-18-nor-5α-cholesta-8,11,13-trien-3β-ol (5). By the same acidic treatment 3β-acetoxy-8α,9α-epoxy-5α-cholestan-7α-ol (6c) generates 3β-hydroxy-5α-cholest-8-en-7-one (7a), and 3β-acetoxy-8α, 14α-epoxy-5α-cholestan-7α-ol (8c) affords 3β-hydroxy-5α-cholest-8(14)-en-7-one (9a) accompanied by the previously unobserved 3β-hydroxy-5α-cholest-8(14)-en-15-one (10a).