反应详情

To a mixture of 1-(5-amino-2-fluoro-4-hydroxy-phenyl)-ethanone (13.2 g, 78 mmol), NaHCO3 (19.67 g, 234 mmol) in water (90 mL), and 4-methyl-2-pentanone (90 mL) at 0° C. was added 2-chloroacetyl chloride (13.22 g, 8.8 mL, 117 mmol) dropwise. After addition, the reaction mixture was stirred at ambient temperature for 0.5 h and then at 80° C. for 18 h. The mixture was cooled to ambient temperature and filtered to give 6-acetyl-7-fluoro-4H-benzo[1,4]oxazin-3-one as gray solid (12 g, 74%), which was used in next step directly without further purification. 1H NMR (DMSO-d6, 400 MHz): δ 10.90 (s 1H), 7.35 (d, J=7.6 Hz, 1H), 7.02 (d, J=11.6 Hz, 1H), 4.71 (s, 2H), 2.47 (d, J=4.8 Hz, 3H).

1. additionAfter addition
2. waitat 80° C. for 18 h
3. temperatureThe mixture was cooled to ambient temperature
4. filtrationfiltered