Step B. 4-Fluoro-3-nitroaniline (5.0 g, 32.0 mmol) and triethylamine (TEA, 6.7 mL, 48.0 mmol) were dissolved in 50 mL of dichloromethane (DCM) at 0 °C. Subsequently, acetyl chloride (2.75 mL, 38.4 mmol) was slowly added dropwise, and after completion of the dropwise addition the reaction mixture was warmed to room temperature and stirred overnight. Upon completion of the reaction, the organic layer was washed sequentially with 5% aqueous potassium bisulfate (KHSO4), saturated aqueous sodium bicarbonate (NaHCO3) and brine, and then dried over anhydrous magnesium sulfate (MgSO4). By concentrating the organic phase and crystallizing from DCM, 5.3 g of N-(4-fluoro-3-nitrophenyl)acetamide was obtained in 84% yield. The structure of the product was confirmed by 1H NMR (400 MHz, chloroform-D): δ 2.04 (s, 3H), 7.51 (dd, J = 11.23,9.08 Hz, 1H), 7.80 (dd, J = 9.08,4.00,2.93 Hz, 1H), 8.47 (dd, J = 7.03,2.73 Hz, 1H), 10.38 (s 1H).
