Intramolecular general base catalysis in the hydrolysis of the ester group of benzoylglycolic acid

Abstract

The mechanism of hydrolysis of the ester group of benzoylglycolic acid in buffered aqueous solutions at 80 °C in the range where the rate is independent of pH was studied. The uptake of ¹⁸O in benzoic acid during hydrolysis in 20%¹⁸O enriched water, the interpretation of a Brønsted correlation of hydrolysis catalysed by some oxy-anions (β 0.49), and the evaluation of activation entropy brought us to the conclusion that the reaction involves the anion of the substrate, and may be interpreted in terms of intramolecular general base catalysis (k_H2o^8–×[H₂O] 1.33 × 10^–6 s^–1, ΔH^‡ 22.5 kcal mol^–1, ΔS^‡–22.2 cal mol^–1 K^–1).