A novel pyrogallol A-ring proanthocyanidin dimer from Acacia melanoxylon
Abstract
The isolation of the natural proanthocyanidin dimer, (+)-2,3-cis-3,3′,4′,7,8-pentahydroxyflavan (4α→ 6) isomelacacidin from Acacia melanoxylon in high yield is in marked contrast to published reports and is evidence that the pyrogallol aromatic ring is sufficiently reactive for nucleophilic condensation to occur in nature forming proanthocyanidin oligomers.