Chemical studies on Sophora tomentosa: the isolation of a new class of isoflavonoid.

Abstract

Two new pterocarpans, sophoracarpans A and B, were isolated from Sophora tomentosa L. (Leguminosae) in addition to three known isoflavonoids, wighteone (erythrinin B), sophoraisoflavanone A and l-maackiain. The structures of sophoracarpans A and B were elucidated as 6β, 9-dimethoxy-3-hydroxypterocarpan and 3-hydroxy-6β-methoxy-8, 9-methylenedioxypterocarpan, respectively, on the spectroscopic basis. The configurations at C-6, C-6a, and C-11a of both compounds were determined by a series of nuclear magnetic resonance irradiation experiments. The isoflavone wighteone, known as an antifungal phytoalexin in several genera of leguminous plants, was also found to occur in the genus Sophora.