Steroids and Walden inversion. Part LXI. Chlorination of 5α-cholestan-2-one

Abstract

Monochlorination of 5α-cholestan-2-one yields 78% of the axial 3α-chloro-ketone, 19% of the equatorial 3β-chloro-ketone, and a little of the 3,3-dichloro-ketone under conditions in which the 3α-chloro-ketone is stable. Chlorination of the enol acetate of 5α-cholestan-2-one affords 3α-chlorocholestan-2-one, with traces of the 3β-chloro-ketone. 1α-Chloro-, 1α,3α-dichloro-, 1α,3β-dichloro-, 3,3-dichloro-, and 1α,3,3-trichloro-5α-cholestan-2-one have been prepared, and their more significant ultraviolet, infrared, optical rotatory dispersion, and nuclear magnetic resonance characteristics are recorded.