On steroids. Part 209. Formation of 6β-bromo-5-chloro-5α-cholestan-3β-ol on addition of bromine chloride to cholesterol

Abstract

On treatment with phosphorus tribromide 3β-acetoxy-5-chloro-5α-cholestan-6β-ol (6) yielded 3β-acetoxy-6β-bromo-5-chloro-5α-cholestane (4) which was converted into the corresponding 3β-hydroxy-derivative (2) and the 3-oxo-derivative (14). Dehydrohalogenation of compound (14) gave the known 6β-bromo-4-cholesten-3-one (15). Compound (2) was found as a product of bromine chloride addition to cholesterol. Results are discussed in terms of stereochemical control of addition of an electrophile to the Δ⁵-double bond.