Synthesis of 5-azaandrostane-3b,17b-diol protected at the 17b-hydroxyl group

In the present paper, the preparation of 3b-hydroxy-17b-dimethyl-tert-butylsilyloxy-5-azaandrostane (15) in fourteen steps is described. B-nor-17-oxoandrost-5-en-3b-yl acetate (1) was used as the starting material, which was transformed to the key intermediate of the synthesis, B-nor-17b-dimethyl-tert-butylsilyloxyandrost-4-en-3b-yl acetate (7).