反应详情

温度

-10 °C

To a solution of 7-fluoro-4H-benzo[1,4]oxazin-3-one (3.00 g, 17.95 mmol) in concentrated H2SO4 (12 mL) at −10° C. was added a mixture of fuming nitric acid (1.131 g, 17.95 mmol, 0.75 mL) and concentrated H2SO4 (0.75 mL) dropwise, keeping the internal temperature below 0° C. After addition, the reaction mixture was stirred at −10° C. for 10 min. The reaction mixture was poured onto crushed ice (200 g) with care. The precipitate was collected by filtration, washed with water (50 mL) and dried in vacuo to give 7-fluoro-6-nitro-4H-benzo[1,4]oxazin-3-one as a light yellow solid (3.5 g, 92%). 1H NMR (DMSO-d6, 400 MHz): δ 11.02 (s, 1H), 7.61 (d, J=7.6 Hz, 1H), 7.23 (d, J=12.0 Hz, 1H), 4.77 (s, 2H).

1. customthe internal temperature below 0° C
2. additionAfter addition
3. additionThe reaction mixture was poured
4. filtrationThe precipitate was collected by filtration
5. washwashed with water (50 mL)
6. customdried in vacuo