Tannins and related compounds. XIX. Eight new gallotannins containing a proto-quercitol core from Quercus stenophylla Makino. (3)

By a combination of adsorption and partition chromatography, eight new proto-quercitol gallates (compounds 1-8) have been isolated from the tannin fraction of the bark of Quercus stenophylla MAKINO (Fagaceae). Their structures have been characterized mainly by 1H-NMR examinations combined with the spin-decoupling techniques as 4, 5-di-O-gallate (1), 3, 4, 5-tri-O-gallate (2), 2, 4, 5-tri-O-gallate (3), 1, 4, 5-tri-O-gallate (4), 1, 3, 5-tri-O-gallate (5), 1, 3, 4, 5-tetra-O-gallate (6), 1, 2, 4, 5-tetra-O-gallate (7) and 1, 2, 3, 4, 5-penta-O-gallate (8) of proto-quercitol (desoxyinositol).