21-Deoxycortisone (17a-hydroxy-4-pregnene-3,11,20-trione)

Abstract

The title compound, C21H28O4, a synthetic glucocorticoid, crystallizes with a single molecule in the asymmetric unit. Ring A is almost in a half-chair conformation, rings B and C are almost in chair conformations, and ring D is between a twist and a 13β-envelope conformation. The A/B ring junction is quasi-trans, whereas the B/C and C/D ring junctions both approach trans characteristics. The molecule as a whole is slightly convex towards the β side, with an angle of 9.60 (2)° between the C10-C19 and C13-C18 vectors. Molecular-packing and hydrogen-bonding (both intra- and intermolecular) interactions play a major role in the structural association of the compound. © 2005 International Union of Crystallography.