2-Amino-5-bromonicotinic acid (2.0 g, 9.20 mmol) was used as raw material, which was mixed with HOBT (1.40 g, 11.2 mmol), EDCI (3.52 g, 18.4 mmol), Et3N (4.68 g, 46.0 mmol) and NH4Cl (2.48 g, 46.0 mmol) in DMF (100 mL) in DMF (100 mL). The reaction mixture was stirred at room temperature overnight. Upon completion of the reaction, the mixture was concentrated under vacuum and subsequently suspended in water and extracted with CH2Cl2. The organic layer was washed with brine, dried over Na2SO4 and concentrated to afford the crude product 2-amino-5-bromonicotinamide (1.80 g, yield: 80%), which could be used in subsequent steps without further purification. The structure of the product was confirmed by 1H NMR (DMSO-d6, 400 MHz) δ 8.14 (dd, J = 4.4 Hz, 2.4 Hz, 2H), 8.04 (s, 1H), 7.46 (s, 1H), 7.37 (s, 2H) and mass spectrum (M + H: 216/218).
