Synthesis of the beta-D-glucuronides of 2,3-, 3,4-, and 2,6-dichlorophenol

The beta-D-glucuronides of 2,3-, 3,4-, and 2,6-dichlorophenol (1-3) were prepared by a modified Koenigs-Knorr synthesis. As the alkaline hydrolysis of perpivaloylated methyl (2,3-dichlorophenyl)-glucuronate 1a led to a dehydrated glucuronide, the preparation of peracetylated methyl dichlorophenylglucuronates with subsequent cleavage of the ester bindings under mild conditions was preferred.