Autooxidation of Δ~(17(20))-20-Hydroxy Derivatives of Steroids. Synthesis of 3β-Acetoxy-17α-hydroperoxy-16α-methylpregn-5-en-20-one and Its Reduction to 17α-Hydroxy Derivative

摘要

An efficient procedure was proposed for the synthesis of 3β-acetoxy-17α-hydroperoxy-16α-methyl-pregn-5-en-20-one. Optimal conditions were found for the combined process including 1,4-addition of methyl-magnesium bromide at the Δ~(16)-20-oxo fragment of dehydropregnenolone acetate and autooxidation of resulting bromomagnesium 3β-acetoxy-16α-methylpregna-5,17(20)-dien-20-olate. The subsequent reduction of the 17α-hydroperoxy group and hydrolysis of the 3β-acetoxy group afforded 17α-hydroxy-16α-methyl-substituted dehydropregnenolone acetate and its 3-hydroxy analog in high yield.