title: 6beta-Azido-7alpha-hydroxy-17-oxo-5alpha-androstan-3beta-yl acetate.
abstract: In the title compound, C21H31N3O4, a potential inhibitor of aromatase, all rings are fused trans. Rings A, B and C have chair conformations which are slightly flattened. Ring D has a 14alpha-envelope conformation. The steroid nucleus has a small twist, as shown by the C19-C10...C13-C18 torsion angle of 6.6 (2) degrees. Ab initio calculations of the equilibrium geometry of the molecule reproduce this small twist, which appears to be due to the steric effect of the 6beta-azide substituent rather than to packing effects.
authors.affiliation: Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade de Coimbra, P-3004-535 Coimbra, Portugal.
authors.forename: J I F
authors.initials: JI
authors.lastname: Paixão
authors.forename: J A R
authors.initials: JA
authors.lastname: Salvador
authors.forename: J A
authors.initials: JA
authors.lastname: Paixão
authors.forename: A Matos
authors.initials: AM
authors.lastname: Beja
authors.forename: M Ramos
authors.initials: MR
authors.lastname: Silva
authors.forename: A M d'A Rocha
authors.initials: AM
authors.lastname: Gonsalves
mesh_terms: D000085:Acetates / Q000737:chemistry; D000731:Androstanes / Q000737:chemistry*; D047072:Aromatase Inhibitors / Q000737:chemistry; D001386:Azides / Q000737:chemistry*; D018360:Crystallography, X-Ray; D015394:Molecular Structure
chemical_list: D000085:Acetates; D000731:Androstanes; D047072:Aromatase Inhibitors; D001386:Azides