反应详情

To a suspension of 18.2 g of 3-amino-7-chloro-1-phenyl-1,2,4-benzothiadiazine-1-oxide in 75 ml dichloromethane is added slowly a solution of 16.1 g mesitylene sulfonylhydroxylamine (MSH) in 90 ml dichloromethane at 0° C. under stirring. Thereafter stirring is continued for one hour at room temperature and the precipitate then sucked off, washed with diethylether and air-dried. Colorless 3,4-diamino-7-chloro-1-phenyl-1,2,4-benzothiadiazine-1-oxide mesitylene sulfonate, m. pt. 225° C., are obtained. To 10.0 g thereof, suspended in 30 ml pyridine are added under stirring 8.3 g trifluoroacetic acid anhydride. After four hours of boiling the solvent is distilled in a water-jet pump vacuum. The residue is partitioned in dichloromethane/aqueous sodium bicarbonate. The organic layer is concentrated and the residue recrystallized from ethanol. A 3.9 g colorless solid product is obtained, m. pt. 167° C.

1. stirringThereafter stirring
2. washwashed with diethylether
3. customair-dried