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

Participants

Reaction Conditions

Reaction Steps

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.

Provenance & Evidence