title: Clostebol acetate.
abstract: The title compound, C(21)H(29)ClO(3) [systematic name (8R,9S,10R,13S,14S,17S)-4-chloro-3-oxoandrost-4-en-17β-yl acetate], is a 4-chloro derivative of testosterone, used as an anabolic androgenic agent or applied topically in ophthalmological and dermatological treatments. The absolute configurations at positions 8, 9, 10, 13, 14 and 17 were established by refinement of the Flack parameter as R, S, R, S, S, and S, respectively. Rings B and C of the steroid ring system adopt chair conformations, ring A has a half-chair conformation, while ring D is in a C(13) envelope conformation. Ring B and C, and C and D are trans fused. In the crystal, molecules are linked by a weak C-H⋯O interaction.
authors.affiliation: Department of Chemistry, Materials and Chemical Engineering "G. Natta", Politecnico di Milano, Via Mancinelli 7, I-20131 Milano,  Italy.
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Maccaroni
authors.forename: Andrea
authors.initials: A
authors.lastname: Mele
authors.forename: Renato
authors.initials: R
authors.lastname: Del Rosso
authors.forename: Luciana
authors.initials: L
authors.lastname: Malpezzi
references.citation: Acta Crystallogr A. 2008 Jan;64(Pt 1):112-22
references.pmid: 18156677