2-Chlorothiophene → 5-Chlorothiophene-2-sulfonyl chloride

Participants

Reaction Conditions

Reaction Steps

An 80-g (0.68 mol) sample of 2-chlorothiophene was added dropwise to a cooled (dry ice/acetone bath, about -10° to -15° C.) and stirred solution of 160 g (1.38 mol) of chlorosulfonic acid. After the addition was completed, the reaction mixture was stirred at 50° C for 2 hours, cooled, and then poured into 250 g of ice. The aqueous reaction mixture was extracted with methylene chloride. The methylene chloride extract was washed with saturated aqueous sodium bicarbonate solution, washed with water, dried over magnesium sulfate, and evaporated to give 40 g of 5-chloro-2-thienylsulfonyl chloride.

Provenance & Evidence