反应详情

3.73 g of 3-cyano-6-(2-fluorophenoxy)-7-methylsulfonylamino-4H-1-benzopyran-4-one was dissolved in 100 ml of formic acid saturated with hydrogen chloride. The mixture was stirred for 24 hours at 25°-30° C. The solvent was removed by distillation under reduced pressure. The residue was mixed with 100 ml of water. The resulting crystal was collected by filtration and recrystallized from acetic acid to obtain 2.54 g (yield: 65%) of 3-carbamoyl-6-(2-fluorophenoxy)-7-methylsulfonylamino-4H-1-benzopyran-4-one. The properties (melting point and IR) of this compound agreed with those of the compound obtained in Example 4.

1. customThe solvent was removed by distillation under reduced pressure
2. additionThe residue was mixed with 100 ml of water
3. filtrationThe resulting crystal was collected by filtration
4. customrecrystallized from acetic acid