General procedure for the synthesis of 2-amino-6-bromopyridin-3-ol from 6-bromo-2-nitropyridin-3-ol: 6-bromo-2-nitropyridin-3-ol (3 g, 13.7 mmol), iron powder (7657.88 mg, 136.99 mmol) and ammonium chloride (7329.1 mg, 136.99 mmol) were reacted with stirring at 75°C for 2 hours in a mixture of ethanol (100 mL) and water (100 mL) in a solvent mixture of ethanol (100 mL) and water, and the reaction was stirred at 75 °C for 2 h. The reaction mixture turned into a black suspension. After completion of the reaction, the mixture was cooled to room temperature and filtered through diatomaceous earth to remove insoluble impurities. The filtrate was concentrated under reduced pressure to afford the crude product 2-amino-6-bromopyridin-3-ol (2.5 g, 13.22 mmol, 96.55% yield) as a solid. The structure of the product was confirmed by 1H NMR (DMSO-d6, 400 MHz): δH= 9.71 (s, 1H), 6.74 (d, 1H), 6.50 (d, 1H), 5.92 (br s, 2H).
