Nitric Acid → 7-Fluoro-6-nitro-2H-1,4-benzoxazin-3(4H)-one

Participants

Reaction Conditions

Reaction Steps

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).

Provenance & Evidence