Pterocarpanoid constituents of the heartwoods of Pericopsis angolensis and Swartzia madagascariensis

Abstract

Ten compounds have been isolated from S. madagascariensis, generally in very small quantity and, where not previously known, their structures have been established by degradative and spectroscopic means, supported in two cases by synthesis. Three of these compounds, homopterocarpin (II; R = Me), demethylpterocarpin (I; R = H), and pterocarpin (I; R = Me) are known, whereas the remaining seven, 3-hydroxy-9-methoxyptero-carpan (II; R = H), 3-hydroxy-4-methoxy-8,9-methylenedioxypterocarpan (X), 3-hydroxy-4,9-dimethoxy-pterocarpan (XIII), 3,4-dimethoxy-8,9-methylenedioxypterocarpan (VII), 3,4,9-trimethoxypterocarpan (XI), 3,9-dimethoxypterocarp-6a-en (XIV), and 3,9-dimethoxy-6-oxopterocarp-6a-en (XVI; R = Me) have not been found previously in nature. The known 3,4,3′,5′-tetrahydroxystilbene and homopterocarpin have been isolated from P. angolensis.