23056-40-8

Beige powder

a) General procedure for the synthesis of 2-chloro-5-methyl-3-nitropyridine: 5-methyl-3-nitropyridin-2-ol (5 g, 32.4 mmol) and benzyltrimethylammonium chloride (3.01 g, 16.2 mmol) were dissolved in acetonitrile, followed by addition of phosphorochloridic acid (9.0 ml, 97.2 mmol). The reaction mixture was stirred at 80 °C for 6 hours. After completion of the reaction, the mixture was cooled to room temperature and slowly poured into ice water to quench the reaction. The aqueous phase was extracted with dichloromethane and the organic layers were combined, washed with saturated brine solution and dried over anhydrous sodium sulfate. After filtration, the solvent was evaporated under reduced pressure to give the crude product. The crude product was purified by silica gel column chromatography using dichloromethane as eluent. The fraction containing the target compound was collected and concentrated under reduced pressure to give 2-chloro-5-methyl-3-nitropyridine as a yellow solid (5.39 g, 97% yield). The product was confirmed by 1H-NMR (CDCl3, 300 MHz) and mass spectrometry (ESI): 1H-NMR δ= 8.45 (d, 1H, J = 2.3Hz), 8.04 (d, 1H, J = 2.3Hz), 2.46 (s, 3H); MS (ESI) m/z: 173.0 ([M+H]+).

[1] Patent: US2011/28467, 2011, A1. Location in patent: Page/Page column 51
[2] Bioorganic and Medicinal Chemistry, 2015, vol. 23, # 5, p. 985 - 995
[3] Patent: EP2366691, 2011, A1. Location in patent: Page/Page column 9
[4] Patent: WO2015/73528, 2015, A1. Location in patent: Page/Page column 118
[5] Journal of the American Chemical Society, 1951, vol. 73, p. 3504