Constitution of oroxylin-A and synthesis of its diethyl-ether

Abstract

The experiments described in this paper show that a pure sample of oroxylin-A melts at 219–20° (acetate, 139–40°), that the substance melting at 231–32° is a mixture of it with chrysin and that this mixture could be separated by fractionation of the acetates. The constitution of oroxylin-A as the 6-methyl ether of baicalein is confirmed by ethylating it to the diethyl ether and showing that the product is identical with a synthetic sample of 6-methoxy-5 : 7-diethoxy flavone. The details of the synthesis are given.