Coumarin and related compounds. Part VIII. Aluminium chloride-catalysed reactions of phenols with methyl methacrylate. A ready synthesis of 6-methylfuro[3,2-g]coumarin and 7-hydroxy-3-methyl-coumarin

Abstract

The direct synthesis of 6-methyltetrahydrofuro[3,2-g]coumarin (II) and 7-hydroxy-3-methyldihydrocoumarin (V) by the condensation of methyl methacrylate with appropriate phenols in the presence of aluminium chloride is described. Dehydrogenation over palladium–charcoal in diphenyl ether gives the fully unsaturated derivatives (III) and (VI).