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

Temperatur

-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

ORD-Eintrag

ord-3997ac9bef4f43229d070b32b70ed8aa

Quelldatensatz

uspto-grants-2015_08

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US09115151B2