11 beta-hydroxyobacunone (zapoterin)

Abstract

The crystal structure of zapoterin C26H30O8 isolated from Casimiroa edulis has been determined and the compound crystallizing in the monoclinic space group P2(1) with a = 7.486(1), b = 16.247(3), c = 9.736(2)Angstrom, beta = 98.77(1)degrees, V= 1170.3(4)Angstrom (3), and Z = 2 was confirmed as 11 beta -hydroxyobacunone (11 beta -hydroxy-14,15:21,23-diepoxy-4,4,8-trimethyl-A,D-di-homo-24-nor-4,17-dioxa-chola-1,20,22-triene-3,7,16-trione) 1. The molecule comprises a tetracyclic skeleton with homo-oxa rings A and D. In the crystal, molecules form infinite ribbons along the b axis by hydrogen bonding involving the hydroxyl group and the carbonyl group of the seven-membered lactone.