Revised structure of cercidinin A, a novel ellagitannin having (R)-hexahydroxydiphenoyl esters at the 3,4-positions of glucopyranose

The structue of cercidinin A, an ellagitannin isolated from the bark of Cercidiphyllum japonicum, was revised to 1,2,6-tri-O-galloyl-3,4-(R)-hexahydroxydiphenol-beta -D-glucose by two-dimensional NMR spectral analysis. Cercidinin A represents the first ellagitannin possessing a hexahydroxydiphenoyl group at the 3,4-positions of a modified C-4(1)-glucopyranose core.