17-Oxo-5α-androst-6-en-3β-yl acetate

Abstract

In the title compound, C 21 H 30 O 3 , a potential inhibitor of aromatase, all rings are fused trans. Rings A and C have chair conformations which are slightly¯attened, whereas the conformation of ring B is close to a half-chair. Ring D has a 14-envelope conformation. The steroid nucleus has a small twist, as shown by the C19ÐC10Á Á ÁC13ÐC18 (steroid numbering) torsion angle of À6.9 (3) . Ab initio calculations of the equilibrium geometry of the molecule reproduce this small twist, which appears to be due to the conformation of ring B rather than to packing effects.