反应详情

A stirred solution of 7-fluoro-1H-3,1-benzoxazine-2,4-dione (9.0 g) in dimethylacetamide (100 ml) at 18.5° was treated portionwise with sodium hydride (80% dispersion in mineral oil, 1.65 ) during 10 minutes. The mixture was stirred for a further 75 minutes. Methyl iodide (7.81 g) was then added dropwise to the stirred mixture during 5 minutes and the mixture was stirred for a further 18.5 hours at ambient temperature. Solvent (60 ml) was removed by distillation in vacuo. The residue was cooled to 3° and poured into ice-water. The resulting precipitate was collected, dried in vacuo and recrystallised from dichloromethane to give 7-fluoro-1-methyl-1H-3,1-benzoxazine-2,4-dione m.p. 158°-159.5°.

1. stirringthe mixture was stirred for a further 18.5 hours at ambient temperature
2. customSolvent (60 ml) was removed by distillation in vacuo
3. temperatureThe residue was cooled to 3°
4. additionpoured into ice-water
5. customThe resulting precipitate was collected
6. customdried in vacuo
7. customrecrystallised from dichloromethane