Stereoselective synthesis of some 17β-dihydrooxazinyl steroids, as novel presumed inhibitors of 17α-hydroxylase-C17,20-lyase

17β-Dihydrooxazinyl steroids 5a–l and 6a–l were synthetized. The acid-catalyzed reactions of 21-azidomethyl-20-hydroxy- and 21-hydroxymethyl-20-azidosteroids with substituted aromatic aldehydes led to the formation of androst-5-en-3β-ols substituted in position 17β with dihydrooxazine residues. The inhibitory effects of these compounds on rat testicular C17,20-lyase were investigated with an in vitro radioincubation technique.