Synthesis of the pyranoisoflavonoid, heminitidulan. Isoflavanoid and rotenoid glycosides from the bark of Dalbergia nitidula Welw. ex Bak.

Abstract

Synthesis of racemates of the complex pyranoisoflavan, (3S)-heminitidulan, a metabolite from the bark of Dalbergia nitidula, is accomplished. The isoflavone C-glycoside pairs 8-C-β-D-glucopyranosyl- and 6,8-di-C-βglucopyranosyl-genistein and -orobol and the associated rotenoid glycoside (5′R,6aR,12aR)-8′-O-β-D-glucopyranosyl-12a-hydroxyamorphigenin comprise the predominant isoflavonoids in the same source. ¹³C N.m.r. spectra of the glycosides are recorded.