N-Iodosuccinimide → 5-Bromo-2-iodopyridin-3-amine

3-Amino-5-bromopyridine (13.8 g, 79.8 mmol) was dissolved in acetic acid (440 mL) and placed under a nitrogen atmosphere. N-Iodosuccinimide (16.15 g, 71.8 mmol) was charged to the reaction which was stirred at room temperature overnight. The reaction was concentrated and the residue partitioned between EtOAc (200 mL) and saturated aqueous sodium hydrogen carbonate (200 mL). The layers were separated and the organic phase was washed with saturated aqueous sodium hydrogen carbonate (200 mL). The aqueous phase was extracted with EtOAc (3×200 mL). The organic extracts were dried over magnesium sulfate, filtered and concentrated. Chromatography (silica; 1.4 Kg packed in 70% DCM:30% heptane, eluting with 70-100% DCM in heptane) gave the title compound (11.5 g). 1H NMR (270 MHz, CDCl3): 7.83 (1H, m), 7.04 (1H, m), 4.33 (2H, br s).