title: Structure of (+/-)-encecanescin.
abstract: C24H30O4, Mr = 382.5, orthorhombic, P212121, a = 13.091 (2), b = 19.711 (1), c = 8.242 (1) A, V = 2126.7 (5) A3, Z = 4, Dx = 1.195 Mg m-3, lamba (Cu K alpha) = 1.54184 A, mu(Cu K alpha) = 0.56 mm-1, F(000) = 824, T = 295 K. Final R = 0.045 for 2446 unique reflections. The planar A ring is bent relative to the rest of the steroid skeleton. The B ring has a typical chair conformation and the C and D rings assume 13 beta,14 alpha-half-chair and 13 beta-envelope conformations, respectively. The conformation of the progesterone side chain is similar to the conformation observed in other 17 alpha-ester pregnanes: C16-C17-C20-O20 torsion angle -27.4(3) degrees.
authors.affiliation: Department of Chemistry, University of Texas, Austin 78712.
authors.forename: K A
authors.initials: KA
authors.lastname: Abboud
authors.forename: S H
authors.initials: SH
authors.lastname: Simonsen
mesh_terms: D001578:Benzopyrans / Q000138:chemical synthesis / Q000737:chemistry*; D008968:Molecular Conformation; D013237:Stereoisomerism; D014961:X-Ray Diffraction
chemical_list: D001578:Benzopyrans; C066390:encecanescin