Evidence consistent with an elimination mechanism in the hydrolysis of aryl N-methylamino-sulphonates

pH-independent rate constants for hydrolysis of the title esters obey a Brønsted relationship with β - 1·85; participation of an elimination mechanism involving MeN=SO₂ intermediate is consistent with the above data (indicating considerable SO bond cleavage in the transition state) with the absence of a glycine buffer effect, and with a 10⁸ fold greater reactivity of the 4-nitrophenyl ester compared with the dimethylamino-ester to reaction with hydroxide ion.