4H-1,4-Benzothiazin-3-one → 3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-sulfonyl chloride

Participants

Reaction Conditions

Reaction Steps

4H-Benzo[1,4]thiazin-3-one (7.0 g) was added cautiously portionwise to chlorosulfonic acid (15 ml) at 0° C. over 20 minutes and the solution was stirred cold for 1 hour and then heated at 45° C. for 2 hours. It was cooled and poured slowly into iced-water. The product was collected, washed well with water and dried in vacuo to give a white solid (7.0 g).

Provenance & Evidence