Process for the preparation of 4-hydroxy-1,2-benzoisothiazol-3(2H)one 1,1-dioxide and salts thereof

摘要

There is described an advantageous process for the preparation of 4-hydroxy-1,2-benzoisothiazol-3(2H)one 1,1-dioxide, which can be used as a sweetener, and of its physiologically acceptable salts, starting from inexpensive compounds of the general formula II <IMAGE> in which Y denotes the hydroxyl group, a halogen atom, the radical OR or the group NR3R4, R1 denotes a nucleophilically exchangeable group or the radical -OR and R2 denotes a hydrogen atom or the carboxyl group. These compounds are reacted with alcoholates of metals of Main Groups 1 and 2 of the Periodic Table under anhydrous conditions at elevated temperatures. The resulting salts can be converted into 4-hydroxy-1,2-benzoisothiazol-3(2H)one 1,1-dioxide.