POLYMORPHISM IN DETHOXYPRONE, A STEROIDAL ANESTHETIC .2. CRYSTAL AND MOLECULAR-STRUCTURE OF 11-ALPHA-DIMETHYLAMINO-2-BETA-ETHOXY-3-ALPHA-HYDROXY-5-ALPHA-PREGNAN-20-ONE (DETHOXYPRONE, FORM-II)

The crystal and molecular structure of 11alpha-dimethylamino-2beta-ethoxy-3alpha-hydroxy-5alpha-pregnan-20-one (Dethoxyprone, form II) (C25H43NO3) has been determined by direct methods, and refined to a final R of 0.067 for 4508 observed reflections. The compound crystallizes in space group P2(1)2(1)2(1) with cell dimensions a = 10. 830 (2), b = 12.703 (2), c = 17.490 (1)angstrom; Z = 4, D(x) = 1.12 g cm-3, mu (CuKalpha) = 5.28 cm-1. The rings of the steroid skeleton are trans connected. Rings A, B, and C have chair conformations, while ring D has a half-chair conformation. The molecules are hydrogen bonded in a head to tail fashion through the hydroxy and keto groups.