title: 21-Hy-droxy-pregna-1,4-diene-3,20-dione.
abstract: The title compound, C(21)H(28)O(3), is a fungal transformed metabolite of decoxycorticosterone acetate, consisting of four fused rings A, B, C and D. Ring A is nearly planar, with a maximum deviation of 0.010 (3) Å from the least-squares plane, while the trans-fused rings B and C adopt chair conformations. The five-membered ring D is in an envelope conformation. The orientation of the side chain is stabilized by an intramolecular O-H⋯O hydrogen bond. In the crystal, adjecent mol-ecules are linked by C-H⋯O hydrogen bonds into extended zigzag chains along the a axis.
authors.affiliation: H.E.J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi 75270,  Pakistan.
authors.forename: S
authors.initials: S
authors.lastname: Yousuf
authors.forename: M
authors.initials: M
authors.lastname: Bibi
authors.forename: M I
authors.initials: MI
authors.lastname: Choudhary
references.citation: Acta Crystallogr A. 2008 Jan;64(Pt 1):112-22
references.pmid: 18156677
references.citation: Acta Crystallogr D Biol Crystallogr. 2009 Feb;65(Pt 2):148-55
references.pmid: 19171970
references.citation: Steroids. 1995 Sep;60(9):646-9
references.pmid: 8545855