Some reactions of substituted 2'- benzyloxychalkone epoxides

Abstract

The behaviour of 2'-benzyloxychalkone epoxides towards acid reagents depends on the presence of substituents in the styryl part as well as on the reaction conditions. Ethereal hydrogen chloride under various conditions have been generally used but acetic acid alone or in conjunction with hydrobromic acid have also been used in a few cases. Simple 2'-benzyloxy-(I) and 2'-benzyloxy-4'-methoxy-(XIV) chalkone epoxides give only dihydroflavonols II and XV respectively; whereas 12'-benzyloxy-4-methoxy-(XIX) and 2',4'-dibenzyloxy-4-methoxy-(III) chalkone epoxides give various products depending on the conditions. From the latter epoxide (III), chlorohydrin (VI), glycol monoacetate (IX), 1,2-diketone (IV), and isoflavones (VII and VIII) have been isolated.