The first natural biflavonoid with flavanol and dihydroflavonol constituent units coupled at the B-ring

Abstract

[2′,2′]-(+)-Catechin-(+)-taxifolin, a novel biflavonoid from commercial willow bark (Salix spp.), is characterized by spectrometric methods, the bonding positions being established by nuclear Overhauser effect difference spectroscopy of the methyl ether acetate of the bi-(+)-taxifolin analogue, which represents a product of oxidation and which undergoes methylene insertion reactions with diazomethane.