Hydrolysis of Glycosides with Microgel Catalysts

A dormant macromolecular catalyst was prepared by polymerization of an aqueous styrene–butyl acrylate miniemulsion in the presence of a new polymerizable pentadentate ligand. The catalyst was activated by binding Cu(II) ions to the ligand site and then explored for its ability to hydrolyze glycosidic bonds in alkaline solution. The performance was correlated to the catalytic activity shown by low molecular weight analogs. A turnover rate of up to 43 × 10–4 min–1 was previously observed for cleavage of the glycosidic bond in selected p-nitrophenylglycosides with a binuclear, low molecular weight catalyst; by contrast, the same reaction is more than 1 order of magnitude faster and has a turnover rate of up to 380 × 10–4 min–1 when using the prepared macromolecular catalyst. The catalyzed hydrolysis is about 105-fold accelerated over the uncatalyzed background reaction under the provided conditions, while a significant discrimination of the α- and β-glycosidic bond or of the galacto- and gluco-configuration in the sugar moiety in the glycoside substrates is not observed.