The Synthesis of 3-Hydroxy-8,9-dimethoxypterocarpan

Abstract 7,2′-Dihydroxy-4′,5′-dimethoxyisoflavone was obtained from 7-hydroxy-2′,4′,5′-trimethoxyisoflavone by selective demethylation with aluminum chloride in acetonitrile. By partial benzylation, the dihydroxyisoflavone then gave 7-benzyloxy-4′,5′-dimethoxy-2′-hydroxyisoflavone. The subsequent treatment of the latter with sodium borohydride afforded 3-hydroxy-8,9-dimethoxypterocarpan via its 3-benzyloxy-compound.