Number Of Chlorine Substituents Research Articles

Acid hydrolysis of methyl chlorodeoxyglycosides

First-order rate coefficients, activation energies, and entropies of activation for the acid-catalysed hydrolysis of methyl β- D-glucopyranoside and seven methyl chlorodeoxyglycopyranosides have been determined on the basis of methanol yield. Increase in the number of chlorine substituents causes a decrease in the rate of hydrolysis. Replacement of the C-2 hydroxyl group by chlorine shows the greatest effect in decreasing the rate. Significant changes were found in the activation parameters; for instance, the entropies of activation were negative for three chlorodeoxyglycopyranosides. This is the first example of glycopyranosides having negative values for entropies of activation.