Kinetics and mechanism of hydrolysis of N-amidomethylsulfonamides

The kinetics of the hydrolyses of secondary and tertiary N-amidomethylsulfo namides were studied at 50 degreesC. Both types of N-amidomethylsulfonamide hydrolyse through acid- and base-catalysed processes, as indicated by the pH-rate profiles. The order of reactivity for the acid-catalysed pathway im plies a mechanism involving protonation of the amide followed by expulsion of a neutral amide and formation of a sulfonyliminium ion. In the base-cata lysed region, compound 5c, which is substituted at both amide and sulfonami de nitrogen atoms, hydrolyses by nucleophilic attack of hydroxide ion at th e amide carbonyl carbon atom to form benzoic acid and a sulfonamide. In con trast, compound 5b, which contains a sulfonamide NH group, hydrolyses to be nzamide and sulfonamide products by an E1cb(rev) mechanism involving ionisa tion of the sulfonamide. Compound 5a, which contains an amide NH, also hydr olyses to sulfonamide and amide products, probably by an E2 mechanism.