Synthesis of 5-bromo-6-hydroxynicotinic acid: 6-hydroxynicotinic acid (8 g, 57.6 mmol) was suspended in water (30 mL) and bromine (4.2 mL, 81.4 mmol) was slowly added under ice bath cooling conditions. After addition, the reaction mixture was stirred at room temperature for 24 hours. Upon completion of the reaction, the solid product was collected by filtration, washed with water and dried in a vacuum oven at 40 °C for 24 h to afford 5-bromo-6-hydroxynicotinic acid (12.1 g, 97% yield) as a tan solid. The structure of the product was confirmed by 1H NMR (400 MHz, DMSO-d6): δ 8.04 (d, J = 2.53 Hz, 1H), 8.16 (d, J = 2.27 Hz, 1H), 12.59 (br s, 1H), 12.90 (br s, 1H).
