Oxidative coupling of the pyrogallol B-ring with a galloyl group during enzymatic oxidation of epigallocatechin 3-O-gallate

Unstable precursors of epigallocatechin-3-O-gallate trimer were isolated after condensation with o-phenylenediamine. The results suggested that oxidative coupling of the galloyl group with the B-ring proceeds by a quinone dimerization mechanism.