Facile self-condensation of melacacidin: a demonstration of the reactivity of the pyrogallol A-ring
Abstract
(–)-2,3-cis-3,4-cis-Flavan-3,3′,4,4′,7,8-hexaol [(–)-melacacidin] reacted rapidly with itself or pyrogallol under mild acidic conditions to yield stereospecific condensation products, suggesting that the formation of natural proanthocyanidins of the 7,8-dihydroxyflavanoid pattern is not chemically prohibited.