Preparation
3-bromo-2-chloro-4-methyl-5-nitropyridine synthesis: 3-bromo-4-methyl-5-nitropyridin-2-ol (133.1 g, 0.57 mol) was suspended in CH3CN (800 mL) and POCl3 (85.2 mL, 1.6 eq) was added dropwise. Subsequently, the reaction mixture was heated at 75 oC for 19 h. The mixture was allowed to cool and poured into 3000 mL of ice-water. The precipitate was isolated by filtration and the residue was washed with water (2*250 mL), dried in vacuo, then stripped with toluene (2*500 mL) and propionitrile (200 mL) at 60 oC. The resulting brown oil, rapidly solidified upon cooling to yield 3-bromo-2-chloro-4-methyl-5-nitropyridine (126.6 g, 88%).
