5-Bromo-2-chloro-3-nitropyridine

5-Bromo-2-chloro-3-nitropyridineA mixture of 5-bromo-3-nitropyridin-2(1 H)-one (Step A, 7.2 g, 32.9 mmol), phosphoryl chloride(72 mL) and λ/, λ/-dimethylformamide (7.2 mL) was stirred under reflux for 2 h. After removal of solvent, the residue was dissolved in water (100 mL) and ethyl acetate(30 mL) and the solution was separated.The organic layer was washed with saturated sodium hydrogen carbonate, dried over sodium sulfate and concentrated to afford the title compound (6.97 g, 89percent) as a pale yellow solid.To a solution of 5-bromo-3-nitropyridin-2(1H)-one (4.62 g, 21.10 mmol) in POClN, N'-dimethylformamide (3 mL) was added to a mixture of 5-bromo-2-hydroxy-3-nitropyridine (16.54 g, 80 mmol) and thionyl chloride (43 mL) and the mixture was stirred and heated to reflux. N, N'-dimethylformamide (3 mL) was added to a mixture of 5-bromo-2-hydroxy-3-nitropyridine (16.54 g, 80 mmol) and thionyl chloride (43 mL) and the mixture was stirred and heated to reflux. After 1 hour, the solution was cooled and the solvent was evaporated. The mixture was co-evaporated with toluene to give a dark solid. Purification by flash chromatography (10:1 hexanes/ethyl acetate) gave the title compound (14.63 g, 82percent) as a yellow solid. A mixture of 5-bromo-2-hydroxy-3-nitropyridine (14) (28.8 g, 131.5 mmol), POClGeneral procedure: 2-Hydroxy-3-nitropyridine 5 (0.015 mol) was suspended in POCl