3-Amino-4,6-dibromopyridine was prepared as follows: a solution of sodium bromide (21.87 g, 212.4 mmol) and sodium bromate (63.76 g, 425.0 mmol) in (400 ml) of water was added to a solution of pyridin-3-amine (20.0 g, 0.213 mol) in acetonitrile (200 ml) at 0-5 C. Then, accompanied by cooling, sulfuric acid (prepared from concentrated sulfuric acid 20.84 g (212.5 mmol) and 200 ml of water) was added over 30 min. The mixture was stirred at 5C for 1h and filtered and the residue was washed with saturated NaHCO3 solution (200 ml) and water (200 ml) and dried under reduced pressure. 40.0 g (quantitative) of the crude product 3-amino-4,6-dibromopyridine was obtained.
