Acid-catalyzed hydrolysis of 5-substituted-1H, 3H-2,1,3-benzothiadiazole 2,2-dioxides (5-substituted benzosulfamides): kinetic behavior and mechanistic interpretations

Abstract

The acid-catalyzed hydrolysis of a series of 5-substituted-1H,3H-2,1,3-benzothiadiazole 2,2-dioxides has been investigated in aqueous solutions of sulfuric, perchloric, and hydrochloric acid at 85.0 +/- 0.05 degrees C. Analysis of the kinetic data by the excess acidity method, Arrhenius parameters, the order of the catalytic effects of strong acids, the kinetic deuterium isotope effect, and the substituent effect have indicated that the hydrolysis of 5-substituted benzosulfamides 1a, 1b, 1c, 1d occur with a mechanistic switchover from A2 to A1 in the studied range: an A2 mechanism in low acidity regions and an A1 mechanism in high acid concentrations. Copyright (c) 2015 John Wiley & Sons, Ltd.