No abstract

No abstract

No abstract

The title compound has been shown to be 6a.7cc-epoxy-5a-hydroxy-l.12-dioxo-22R-witha-2.24-dienolide. This is the first natural 12-oxowithanolide isolated so far.THE withanolides are a series of related steroidal lactones possessing an ergostane skeleton in which a six-memberedring 22-hydroxy-26-oic acid lactone is present ; more than 30 compounds of this type have been isolated so far from different Solanaceae.From Nicandra physaloides, nicandrenone, a probably impure compound, m.p. 102-105", has been isolated and described without any assignment of structural formula; 2 a ~b the crude extract was reported 2b to contain a second compound, but no further information was given.A reinvestigation of the constituents of N . physaloides was undertaken. The structural elucidation of nicandrenone is in progress, however, the second compound, for which the name withanicandrin is proposed, has now been identified as 6a,7cr-epoxy-5a-hydroxy-l, 12-dioxo-22R-witha-2,24-denolide (I).Withanicandrin, C, H, O, (I), which is the first natural occurring 12-oxowithanolide, was isolated by chromatographic fractionation of the extract of the leaves of N . physaloides. Following catalytic hydrogenation the-dienolide (I) afforded the dihydro-derivative 2-0 H (11) ; U.V. spectroscopy (see Experimental section) indicated the disappearance of an +unsaturated ketone chromophore.

No abstract