Kinetics of the mutarotation of α-D-tetramethylglucose in aqueous dioxan and dimethyl sulphoxide solution

Abstract

The kinetics of the mutarotation of α-D-tetramethylglucose have been studied by following their optical rotations in solution of water in dioxan and in dimethyl sulphoxide, over a wide range of water concentrations, with and without the addition of catalysts. The results in both solvents suggest that in the ‘uncatalysed’ reaction the transition state contains one molecule of glucose and two molecules of water in a cyclic hydrogen-bonded structure; in the pyridine-catalysed reaction one molecule of water may be replaced by a molecule of the base. The balance of evidence suggests that the reaction takes place by an intimate step-wise mechanism rather than a synchronous process.