Reaction of 6-Oxocholest-4-en-3β-yl acetate with perbenzoic acid

Abstract

Oxidation of 6-oxocholest-4-en-3β-yl acetate (1) with 1 mol. equiv. of perbenzoic acid (and p-toluene-sulphonic acid monohydrate as catalyst) gave 4-hydroxycholesta-2,4-dien-6-one (2a), 7α-hydroxy-6-oxocholest-4-en-3β-yl acetate (3a), 3β-acetoxy-7-oxo-6,7-secocholest-4-en-6-oic acid (4a) and 5-oxo-5,6-secocholest-3-en-6-oic acid (5). When treated with an excess of perbenzoic acid (2.5 mol. equiv.), (1) provided (4a), (5) and 3β-acetoxy-6,7-secocholest-4-ene-5,8-dicarboxyic acid (6). In each case, none of the expected ε-lactones (3c) and (3d) were isolated. The products have been characterized on the basis of their spectral properties, chemical transformations and comparison with authentic samples where available.