Kinetics of the hydrogen chloride/methanol-catalyzed mutarotation reactionof N-(p-chlorophenyl)-beta-D-glucopyranosylamine

The rate of hydrogen chloride-catalyzed mutarotation reaction of N-(p-chlor ophenyl)-beta-D-glucopyranosylamine has been studied polarimetrically in ab solute methanol at 25 degrees C. Depending on the HCl concentration, conver sion of isomer beta to isomer alpha has been found to be either a simple ps eudo-first order reaction or a complex process involving two parallel first -order reactions producing a common product. The rate constants of the reac tions and their dependence on hydrogen ion concentration have been determin ed. it was demonstrated that a relatively stable N-glucoside . H+ cation wa s an intermediate product. Elementary rate constants for two reversible ste ps of the reaction have been determined, as well.