tert-Butyl chloroacetate → Tert-butyl 2-(1,1-dioxido-3-oxobenzo[D]isothiazol-2(3H)-YL)acetate

Participants

Reaction Steps

A solution of 22.6g (0.11 mole) of sodium saccharin and 15g (0.1 mole) of tert-butyl α-chloroacetate in 150 ml of dimethylformamide is heated on a steam bath for 1 hour, allowed to stir at room temperature for 16 hours and poured into ice-water. The solution is dried over magnesium sulfate and the solvent is evaporated to give 24.9g of tert-butyl N-saccharinylacetate, m.p. 130°-132.5° C. This is refluxed with 300 ml of benzene and 1.4g (0.01 mole) of p-toluenesulfonic acid monohydrate to cause quantitative precipitation of 2-carboxymethylsaccharin, m.p. 212°-215° C. The completion of the reaction is established by passing a slow stream of nitrogen through the reaction mixture and into solution of bromine in carbon tetrachloride. Failure to decolorize the bromine indicates that no more isobutylene is being evolved.

Provenance & Evidence