Aromatization of some 4,5-epoxy-3-hydroxysteroids
Abstract
Treatment of the epimeric 17β-acetoxy-4,5-epoxyandrostan-3β-ols with hydrogen bromide in glacial acetic acid gave 17β-acetoxy-4-methyloestra-1,3,5(10)-triene by a dienol–benzene pathway. Under the same conditions 3β-hydroxy-4β,5β-epoxyandrostane-6,17-dione gave 1-methyloestra-1,3,5(10)-triene-6,17-dione, whilst 3β,17β-diacetoxy-4α,5α-epoxyandrostan-11-one gave a low yield of 17β-acetoxy-4-methyloestra-1,3,5(10)-trien-11-one, revealing that the influence of the carbonyl groups at C-6 and C-11 on this reaction is similar to that on the dienone–phenol rearrangement.