title: Structure of 6 alpha-methyl-3,20-oxo-1,4,9(11)-pregnatrien-17 alpha-yl acetate.
abstract: C24H30O4, Mr = 382.5, orthorhombic, P2(1)2(1)2(1), 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, lambda(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: Technical University of Lódź, Institute of General Chemistry, Poland.
authors.forename: Z
authors.initials: Z
authors.lastname: Gałdecki
authors.forename: P
authors.initials: P
authors.lastname: Grochulski
authors.forename: Z
authors.initials: Z
authors.lastname: Wawrzak
authors.forename: W L
authors.initials: WL
authors.lastname: Duax
authors.forename: P D
authors.initials: PD
authors.lastname: Strong
mesh_terms: D008968:Molecular Conformation; D011281:Pregnatrienes / Q000737:chemistry*; D011374:Progesterone / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D011281:Pregnatrienes; C066389:6-methyl-3,20-dioxo-1,4,9(11)-pregnatrien-17-acetate; D011374:Progesterone