A method for the preparation of p - chloranilinarmem ethanol - 2 - (4 - aminophenyl) sulfonyl - hydrogen sulfate or its alkali metal salts

摘要

Process for synthesis of ethanol-2-(4-aminophenyl)-sulphonylhydrogen sulphate (parabase ester) of formula (I) comprises (i) sulphochlorination of acetanilide with chlorosulphonic acid and thionyl chloride in the presence of a bromide and/or an iodide to form p-acetanilide sulphochloride (II); (ii) reduction of the chlorosulphonyl group of the (II) to the sulphinate; (iii) saponification of the N-acetyl group and (iv) ethoxylation and esterification of the p-acetamino-benzenesulphinate. M = H or alkali metal.