Synthesis of Hibiscetin

Abstract

A convenient method of preparing 2:4-dihydroxy-ω:3:6-trimethoxyacetophenone (I) directly from 2:6-dibenzyloxy-1:4-dimethoxybenzene is described. By the condensation of (I) with the sodium salt and anhydride of trimethylgallic acid, 7-hydroxy-3:5:8:3':4':5'-hexamethoxyflavone (II) is obtained. Methylation of (II) yields a heptamethyl ether (III) identical with heptamethyl hibiscetin. Demethylation of (II) gives rise to a heptahydroxy flavone (IV) which is found to be identical with hibiscetin in all its properties and reactions. The constitution of hibiscetin is therefore confirmed by synthesis as 3:5:7:8:3':4':5'-heptahydroxy flavone.