Chloroacetyl chloride → 6-Nitro-2H-1,4-benzoxazin-3(4H)-one

Temperature

80 °C

To a solution of 2-amino-4-nitrophenol (114.0 g, 740 mmol), K2CO3 (306.2 g, 2220 mmol) and tetrabutyl ammonium bromide (23.8 g, 74 mmol) in MeCN (1.50 L) at 0° C. was added 2-chloroacetyl chloride (83.6 mL, 1110 mmol) dropwise. The reaction mixture was heated at 80° C. for 1 h. The mixture was cooled to ambient temperature and concentrated in vacuo. The residue was dissolved in water (500 mL) and extracted with EtOAc (3×150 mL). The combined organic phase was dried over anhydrous Na2SO4 and filtered. The filtrate was evaporated in vacuo to give 6-nitro-2H-benzo[1,4]oxazin-3-one as a white solid (135.0 g, 94%). 1H NMR (DMSO-d6, 400 MHz): δ 7.83 (dd, J=2.8 Hz, J=9.2 Hz, 1H), 7.75 (d, J=2.8 Hz, 1H), 7.15 (d, J=9.2 Hz, 1H), 4.78 (s, 2H). The amide proton was not observed in DMSO-d6.

1. temperatureThe mixture was cooled to ambient temperature
2. concentrationconcentrated in vacuo
3. dissolutionThe residue was dissolved in water (500 mL)
4. extractionextracted with EtOAc (3×150 mL)
5. dry with materialThe combined organic phase was dried over anhydrous Na2SO4
6. filtrationfiltered
7. customThe filtrate was evaporated in vacuo

ORD record

ord-cad0cf8e4cb2400aaff8198c230d39d6

Source dataset

uspto-grants-2015_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09115151B2