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

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Abstract

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
Divisions:	UNSPECIFIED
Depositing User:	Mr. Amit Nargotra
Date Deposited:	19 Dec 2011 07:09
Last Modified:	19 Dec 2011 07:09
URI:	http://iiim.csircentral.net/id/eprint/181

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