Selectivity of the Hydrogenation of 2',4',7-Tribenzyloxyisoflavone

Abstract

Hydrogenation of 2',4',7-tribenzyloxyisoflavone (1) on a palladium/carbon catalyst gave nine products ranging from 4',7-dibenzyloxy-2'-hydroxyisoflavone (7) to 3,9-dihydroxypterocarpan (demethylmedicarpin ) (5) and 2',4',7-trihydroxyisoflavan (6), depending on the conditions. The benzyl groups of partially debenzylated products were located by ¹H n.m.r.COSY experiments and chemical shift patterns.