The structure of methyl (6R)-6-(3' beta-acetoxy-5'-androsten-17' beta-yl)-2
-phenyl-5,6-dihydro-4H-[1,3]oxazine, C31H41NO3, synthesized from an azidopr
egnene derivative, is reported. The dihydro-1,3-oxazine ring is connected i
n the beta position to the sterane skeleton at C-17'. An R configuration wa
s found at C-6.