PROCESS FOR PREPARING 4-ALKYL-3-CHLOROALKYLSULFONYL BENZENES Russian patent published in 1999 - IPC

FIELD: chemical industry. SUBSTANCE: process for preparing 4-alkyl-3-chloroalkylsulfonyl benzenes of formula 1: wherein R¹ and R² are the same or different and are (C₁-C₄)-alkyl. The process comprises chlorinating ep-alkyl-benzenesulfonic acid chloride of formula 2: wherein R¹ is as defined above, with at least 1 mole of chlorine in the presence of chlorine carriers at about 90-100 C to obtain compound of formula (3): wherein R¹ is as defined above. Said compound is then reduced at about 40-90 C with sodium hydrosulfite or sulfite to obtain compound of formula (4): wherein R¹ is as defined above. Compound (4) is condensed with α-halogenocarboxylic acid of formula (5): wherein R is hydrogen or (C₁-C₃) alkyl, and X is bromine or chlorine, or with one of salts thereof to obtain 4-alkyl-3- chlorobenzenesulfonyl carboxylic acid of general formula (6): wherein R¹ and R are as defined above, or one of salts thereof. Compound (6) is then decarboxylated by heating. EFFECT: simplified technology of preparation of desired compounds. 9 cl, 6 ex