Autooxidation of Δ17(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 3 beta-acetoxy-17 alpha-hydroperoxy-16 alpha-methyl-pregn-5-en-20-one. Optimal conditions were found for the combined process including 1,4-addition of methyl-magnesium bromide at the Delta(16)-20-oxo fragment of dehydropregnenolone acetate and autooxidation of resulting bromomagnesium 3 beta-acetoxy-16 alpha-methylpregna-5,17(20)-dien-20-olate. The subsequent reduction of the 17 alpha-hydroperoxy group and hydrolysis of the 3 beta-acetoxy group afforded 17 alpha-hydroxy-16 alpha-methyl-substituted dehydropregnenolone acetate and its 3-hydroxy analog in high yield.
Autooxidation of Δ17(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 3 beta-acetoxy-17 alpha-hydroperoxy-16 alpha-methyl-pregn-5-en-20-one. Optimal conditions were found for the combined process including 1,4-addition of methyl-magnesium bromide at the Delta(16)-20-oxo fragment of dehydropregnenolone acetate and autooxidation of resulting bromomagnesium 3 beta-acetoxy-16 alpha-methylpregna-5,17(20)-dien-20-olate. The subsequent reduction of the 17 alpha-hydroperoxy group and hydrolysis of the 3 beta-acetoxy group afforded 17 alpha-hydroxy-16 alpha-methyl-substituted dehydropregnenolone acetate and its 3-hydroxy analog in high yield.