PURPOSE: To obtain the subject compound in high yield and purity in a short process by reacting m-difluorobezene with chlorosulfonic acid to provide a 2,4-difluorobenzenesufonyl chloride and reducing the resultant compound with a metal and acid.
CONSTITUTION: m-Difluorobenzene (DFB) is reacted with chlorosulfonic acid (CS), preferably at 5.0-8.0 molar ratio of the CS to the DFB at 30-70°C temperature to provide 2,4-difluorobenzenesulfonyl chloride (DFSC), which is then reduced with a metal having preferably -2.4<(V)<0 normal electrode potential (V), especially zinc and an acid, preferably a mineral acid (especially sulfuric acid) or a lower alkylcarboxylic acid, preferably at 4.5-6.0 molar ratio of the metal to the DFSC and 4.5-8.0 molar ratio of the acid to the DFSC at 30-100°C temperature to industrially and advantageously afford the subject compound useful as an intermediate for medicines, agricultural chemicals, etc., in high reaction and conversion rates.
TATSUMAE SATO
YOSHINO SUMIO
