title: 21-deoxycortisone (17alpha-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 13beta-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 beta side, with an angle of 9.60 (2) degrees 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.
authors.affiliation: Centre for Structural Biology, Department of Chemistry and Bioscience, Chalmers University of Technology, Box 462, Gothenburg 40530, Sweden.
authors.forename: Raja
authors.initials: R
authors.lastname: Dey
authors.forename: Vratislav
authors.initials: V
authors.lastname: Langer
authors.forename: P
authors.initials: P
authors.lastname: Roychowdhury
authors.forename: S
authors.initials: S
authors.lastname: Roychowdhury
authors.forename: M G B
authors.initials: MG
authors.lastname: Drew
mesh_terms: D003348:Cortisone / Q000031:analogs & derivatives* / Q000737:chemistry; D018360:Crystallography, X-Ray; D006860:Hydrogen Bonding; D008958:Models, Molecular; D008968:Molecular Conformation
chemical_list: C020882:21-deoxycortisone; D003348:Cortisone