Chlorzoxazone → 5-Chloro-2-oxobenzoxazoline-6-sulphonyl chloride

Participants

Reaction Steps

5-Chloro-3H-benzooxazol-2-one (10.0 g, 59 mmol) was added in portions to chlorosulfonic acid (30 mL) at −20° C. with stirring. The mixture was stirred at room temperature for 2.5 hours and at 70° C. for 1.5 hours. The cooled reaction mixture was poured slowly into iced-water (300 mL) and stirred for 1 hour. The precipitate was collected and washed with water. The dried precipitate was stirred in chloroform (500 mL) for 3 hours at room temperature, filtered off and dried to give 12.3 g of a pale pink solid.

Provenance & Evidence