Synthesis of gallotannins.

As a contribution to the synthesis of gallotannins, four O-galloyl-D-glucoses (3-O-, 6-O-, 3,6-di-O-, 3,4,6-tri-O-galloyl-D-glucose) have been prepared by the reaction of tri-O-benzylgalloyl chloride and partially protected glucose derivatives (1,2-O-, and 1,2:5,6-di-O-isopropylidene-alpha-D-glucofuranose), followed successively by catalytic debenzylation (Pd-C) and controlled acid hydrolysis. Their structures were established from their behavior on TLC and from their 1H and 13C NMR spectra.