Abstract: Dutasteride, a new kind of antibenign prostatic hyperplasia drug, 17-β-N(2,5-bis(trifluoromethyl)) phenylcarbamoyl-4-aza-5-α-androst-1-en-3-one, was synthesized by employing amidation and DDQ/BSTFA oxidation as a pivotal step from the starting material 3-oxo-4-androstene-17-β-carboxylic acid. The total yield of dutasteride synthesi zed was 23%. The structures of the target molecule and the key intermediates were confirmed by IR,¹H NMR, ¹³C NMR and MS. The route does not require high pressure and high temperature that may be applied to industrial production.

Key words: synthesis, dutasteride, medicinal chemistry, antibenign prostatic hyperplasia drug