The chlorination of 5α- and 5β-cholestan-3-one and dechlorination of 2,2,4α-trichloro-5α-cholestan-3-one and 2β,4,4-trichloro-5β-cholestan-3-one

Abstract

Chlorination of Sα- and 5β-cholestan-3-one (l) and (7) proceeds sequentially to give the α-monochloro (2) and (8), α,α-dichloro (3) and (9), and α, α, α'-trichloro (4) and (10) derivatives; the nature of the product mainly depends on the reaction conditions. The α, α'-dichloro ketones (5) and (11) could be prepared by dechlorination of the corresponding trichloro ketones (4) and (10) with chromium(II) acetate. Further dechlorination of the dichloro ketones (5) and (11) with the same reagent furnished the α-monochloro ketones (6) and (12) which cannot be obtained by the direct chlorination of 5α- and 5β-cholestan-3-one.