In a 500mL three-necked flask equipped with a stirrer and a reflux condenser, 20.7g (0.15mol) of 2-aminonicotinic acid and 80mL of acetic acid were added. The mixture was stirred at room temperature. A mixture of 40mL of acetic acid and 4.1mL of bromine (0.08mol) was added dropwise using a constant-pressure dropping funnel. Stirring continued for 4-5 hours after the addition was complete. The mixture was filtered, washed with acetic acid, dried, and the solid was heated under reflux with 100mL of methanol for 10 minutes, then allowed to stand at room temperature, filtered, and dried. 31.2g of a white solid, 2-amino-5-bromonicotinic acid, was obtained, with a yield of 96%.
1H NMR (400MHz, DMSO-d6)δ12.72(s,1H),9.05(d,J＝2.4Hz,1H),8.63(d,J＝2.4Hz,1H),8.36(s,1H).MS: m/z(ESI+)228.3[M+H]+.
