The synthesis of 3 beta-substituted analogues of 15-ketosterol

A chemical synthesis of 3 beta-(2-propenyloxy)-, 3 beta-[2(R,S)-2,3-oxidopr opyloxy]-, 3 beta-[2(R,S)-2,3-dihydroxypropyloxy]-, 3 beta-(2-oxoethoxy)-, 3 beta-[2(R,S)-2-acetoxy-3-acetamidopropyloxy]-, 3 beta-[2(R,S)-2-hydroxy-3 -acetamidopropyloxy]-, 3 beta-[2(R,S)-2-hydroxy-3(7-nitrobenzo-2-oxa-1,3-di azol-4-ylaminno)propyloxy]-, and 3 beta-[2(R,S),2-hydroxy-3-(5-dimethylamin onaphtalenesulfonylamido)propyloxy]-5 alpha-cholest-8(14)-en-15-ones was ca rried out. 3 beta-(2-Propenyloxy)-5 alpha-cholesta-7,14-diene was prepared from 5 alpha-cholesta-7,14-dien-3 beta-ol by reaction with allyl bromide in the presence of tert-BuOK in DMSO-toluene. The product was converted to 3 beta-(2-propenyloxy)-5 alpha-cholest-8(14)-en-15-one by selective 14 alpha, 15 alpha-epoxidation followed by acid-catalyzed isomerization. The allyl d ouble bond in 3 beta-(2-propenyloxy)-5 alpha-cholest-8( 14)-en-15-one was o xidized with m-chloroperbenzoic acid in boiling chloroform, and the resulti ng epoxide was transformed into the final products by usual approaches with out affecting the ketosterol backbone.