title: 17-Oxo-5alpha-androstane-3alpha,4beta-diyl diacetate and 17-oxo-5beta-androstane-3alpha,4beta-diyl diacetate.
abstract: The title compounds, both C23H34O5, are the 5alpha and 5beta configurations of two diacetate epimers. The 5beta-diacetate crystallizes in an hexagonal structure, unusual for steroid molecules. The unit cell has an accessible solvent volume of 358 A(3), responsible for clathrate behaviour. The 5beta-epimer also features some shorter than average bond lengths in the 3alpha,4beta-acetoxy groups. The conformations of the molecules of both epimers are compared with those obtained through ab initio quantum chemistry calculations. Cohesion of the crystals can be attributed to van der Waals and weak molecular C-H...O interactions.
authors.affiliation: CEMDRX, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade de Coimbra, P-3004-516 Coimbra, Portugal.
authors.forename: L C R
authors.initials: LC
authors.lastname: Andrade
authors.forename: J A
authors.initials: JA
authors.lastname: Paixão
authors.forename: M J M
authors.initials: MJ
authors.lastname: de Almeida
authors.forename: F M
authors.initials: FM
authors.lastname: Fernandes Roleira
authors.forename: E J
authors.initials: EJ
authors.lastname: Tavares da Silva
mesh_terms: D000085:Acetates / Q000737:chemistry*; D000731:Androstanes / Q000737:chemistry*; D047072:Aromatase Inhibitors / Q000737:chemistry*; D018360:Crystallography, X-Ray; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure
chemical_list: D000085:Acetates; D000731:Androstanes; D047072:Aromatase Inhibitors