New pterocarpenes from Brya ebenus

Abstract

Five pterocarpenes (bryacarpenes 1–5) and an isoflavan (bryaflavan) have been isolated from the heartwood of Brya ebenus and identified as 4,10-dihydroxy-3,8,9-trimethoxy-, 10-hydroxy-3,8,9-trimethoxy-, 3,8,9,10-tetramethoxy-, 4-hydroxy-3,9,10-trimethoxy-, and 3,9,10-trimethoxy-6H-benzofuro[3,2-c][1]benzopyran, and (3S)-3′,6,7-trihydroxy-2′,4′-dimethoxyisoflavan.

Pterocarpenes and pterocarpans can be oxidised to coumestones, and chromans to coumarins, by using dichlorodicyanobenzoquinone.