Structure elucidation of cordifolin A, a novel cucurbitacin from Fevillea cordifolia, using one and two dimensional n.m.r. techniques
Abstract
Cordifolin A (3)[3β,16α-dihydroxy-20,25-epoxy-19(10 → 9β)-abeo-10α-lanost-5-en-11,22-dione] was isolated from the methanol-soluble fraction of the 1% tartaric acid extract of dried seeds of Fevillea cordifolia L. (Cucurbitaceae) used in Jamaican folk medicine. Structure elucidation was based primarily on the use of multi-pulse n.m.r. techniques, especially combination of long range and direct 1H,1H INADEQUATE and 1H, 13C chemical shift correlation spectra. Biosynthesis of this novel triterpene apparently involves cyclization of the side chain to give a six-membered ether ring which is unprecedented among cucurbitacins.