反应详情

温度

80 °C

To a mixture of 6-acetyl-7-fluoro-2H-benzo[b][1,4]oxazin-3(4H)-one (12 g, 57.4 mmol) and K2CO3 (11.89 g, 86 mmol) in acetone (120 mL) was added ethyl 2-bromopropanoate (23.6 mL, 172 mmol) and the mixture was stirred and heated at 80° C. for 16 h. The mixture was cooled to ambient temperature and the solvent was removed in vacuo. The residue was purified by column chromatography on silica gel (eluting with 5-10% EtOAc in petroleum ether) to give ethyl 2-(6-acetyl-7-fluoro-3-oxo-2H-benzo[b][1,4]oxazin-4(3H)-yl)propanoate as a gray solid (13.2 g, 74.4%). 1H-NMR (CDCl3, 400 MHz): δ 7.40 (d, J=6.4 Hz, 1H), 6.80 (d, J=10.8 Hz, 1H), 5.24 (q, J=11.2 Hz, 1H), 4.66 (q, J=15.2 Hz, 2H), 4.23 (m, 2H), 2.60 (d, J=5.2 Hz, 3H), 1.63 (d, J=7.2 Hz, 3H), 1.23 (t, 3H).

1. temperatureThe mixture was cooled to ambient temperature
2. customthe solvent was removed in vacuo
3. customThe residue was purified by column chromatography on silica gel (eluting with 5-10% EtOAc in petroleum ether)