Constitution of butrin

Abstract

On treatment with diazomethane, butrin gives rise to a monomethyl ether which yields on hydrolysis with acids a mixture of 4'-O-methylbutin and 4'-O-methylbutein, the latter being the major component. The constitutions of these two products have been established by alkaline oxidation, yielding isovanillic acid and comparison with synthetic samples. It is, therefore, concluded that butrin is 3': 7-diglucoside of butin, and thus it is the first instance of a glycoside to contain the sugar residues in two different positions amongst the group of anthoxanthins and also the first instance to carry a sugar group in the side phenyl nucleus amongst both anthoxanthin and anthocyanin pigments.