Phosphorus oxychloride → 2-Chloro-5-methyl-3-nitropyridine

5-methyl-3-nitro-pyridin-2-ol (5 g, 32.4 mmol) and benzyltrimethyl ammonium chloride (3.01 g, 16.2 mmol) were dissolved in acetonitrile, and phosphorus oxychloride (9.0 ml, 97.2 mmol) was added thereto and stirred at 800 for 6 hours. The reaction mixture was cooled and poured into ice water to quench the reaction, and extracted with dichloromethane. The combined organic layer was washed with saturated saline solution, dried over anhydrous sodium sulfate (Na2SO4), filtered and evaporated under reduced pressure. The residue was purified by column chromatography on silica eluting with a solvent of dichloromethane. The fractions containing the product were collected and evaporated to obtain 2-chloro-5-methyl-3-nitro-pyridine as yellow solid (5.39 g, 97%).