The crystal and molecular structure of 3 beta-acetoxy-5, 6 beta-dichloromethylene-5 beta-androstan-17-one.

The compound 3 beta-acetoxy-5, 6 beta-dichloromethylene-5 beta-androstan-17-one crystallizes in the orthorhombic space group, P212121, with four molecules per unit cell, having the following dimensions: a = 7.936(2) A, b = 11.593(2) A, and c = 22.955(4) A. X-ray analysis of single crystal data (1764 observed reflections), collected on a Syntex P1 autodiffractometer, led to complete structural assignment. Solution by direct methods and refinement by least-squares calculations resulted in a final R of 0.037. The conformation of ring A represents one of the few examples of a distorted boat and ring B approximates a distorted chair, both conformations attributable to the strain of the cyclopropyl ring. The spatial relationship between the endo chlorine atom, and the angular methyl group, C(19) is 3.095(5) A. Ring C is a normal chair and ring D adopts a 13 beta-envelope conformation. The steroid molecules pack perpendicular to the c axis with screw axes intersecting the A-B ring junction.