Patent ID: 6258984
Filing Date: 2001-07-10
Classification: C07C

Abstract:
A process for the preparation of a 4-alkyl(C.sub.1 -C.sub.4)-sulfonyl-1-alkyl-2-chlorobenzene of the formula (4) ##STR7##in which R.sub.1 and R.sub.2 are identical or different alkyl groups having 1 to 4 carbon atoms, which comprises selectively chlorinating 1 mol of a p-alkylbenzene-sulfonyl chloride of the formula (1) ##STR8##in which R.sub.1 has the meaning given above, with at least 1 mol of gaseous chlorine in the presence of a chlorine carrier at temperatures of about 50.degree. C. to about 100.degree. C. to give the compound of the formula (2) ##STR9##in which R.sub.1 has the meaning given above, subsequently reducing the latter in an aqueous medium at a pH of about 8 to about 10 with 1 to about 1.2 mol of sodium hydrogen sulfite or sodium sulfite at temperatures of about 40 to about 90.degree. C. to give a compound of the formula (3) ##STR10##in which R.sub.1 has the meaning given above, and reacting the latter with 1 to about 2.2 mol of alkyl(C.sub.1 -C.sub.4) chloride in the presence of an acid binder at temperatures of about 80 to about 150.degree. C. to give the compound of the formula (4) mentioned above.