Bandhoria, Pankaj and Gupta, Vivek K. and Amina, Musarat and Satti, Naresh K. and Dutt, Prabhu and Suri, Krishan A. (2006) 6α,7α-epoxy-5α,17α,dihydroxy-1-oxo-22R-witha-2,24-dienolide in leaves of Withania somnifera: Isolation and its crystal structure. Journal of Chemical Crystallography, 36 (2). pp. 153-159. ISSN 1074-1542

[img] PDF
Restricted to Registered users only

Download (501Kb) | Request a copy


6α,7α-epoxy-5α,17α,dihydroxy-1-oxo-22R-witha-2,24-dienolide (C28H38O6) was isolated from Withania somnifera leaves. The structure of the withanolide was established by spectral analysis and X-ray diffraction studies as withanone. The compound crystallizes in the orthorhombic space group P212121 with unit cell parameters: a=9.191(10) A° , b=12.858(6) A° , c=21.400(16) A° , Z=4. The crystal structure was solved by direct methods and refined to R=0.0603 for 1742 observed reflections. There is positional disorder of the H atom in a hydroxy group (O5), resulting in two possible hydrogen-bond linkages. All the rings of the steroid skeleton are trans connected. Ring A exists in a half-chair conformation, ring B is intermediate between a half-chair and a sofa, ring C a distorted chair, and five-membered ring D is intermediate between a half-chair and an envelope. The δ-lactone ring E adopts a sofa conformation. The twist along the length of the steroid nucleus is negligible [C19–C10. . .C13–C18=1.8◦]. Both the hydroxy groups are involved in hydrogen bonding.

Item Type: Article
Subjects: Chemical Sciences
Depositing User: Mr. Amit Nargotra
Date Deposited: 19 Dec 2011 07:09
Last Modified: 19 Dec 2011 07:09

Actions (login required)

View Item View Item