Imidazole → 3beta-(Tert.-butyldimethylsilyloxy)-7beta-hydroxy-15beta,16beta-methylene-5-androsten-17-one

Participants

Reaction Conditions

Reaction Steps

A solution of 120 g of 3β,7β-dihydroxy-15β,16β-methylene-5-androsten-17-one in 1,000 ml of dimethylformamide is combined with 31 g of imidazole and cooled to -20° C. Within 2 hours, 63 g of tert.-butyldimethylchlorosilane in 450 ml of dimethylformamide is added dropwise to the reaction mixture, and the latter is agitated for another hour. The reaction product is precipitated with sodium-chloride-containing water, filtered off, washed with water, and dissolved in methylene chloride. The solution is dried over sodium sulfate and evaporated. After chromatography on silica gel with hexane-acetone, 128.8 g of 3β-(tert.-butyldimethylsilyloxy)-7β-hydroxy-15β,16β-methylene-5-androsten-17-one is obtained.

Provenance & Evidence