Preparation of 20-(hydroxymethyl)-4-methyl-4-aza-2-oxa-5 alpha-pregnan-3-one as an inhibitor of testosterone 5 alpha-reductase

20-(Hydroxymethyl)-4-methyl-4-aza-2-oxa-5 alpha-pregnan-3-one and the corresponding 3-thione were synthesized with use of 20-(hydroxymethyl)-4-methyl-4-aza-5 alpha-pregnan-3-one as the starting material. The compounds were tested in vitro for inhibition of testosterone 5 alpha-reductase and found to be weak inhibitors with Ki's in the 10(-7) range.