Synthesis
General procedure for the synthesis of 2-hydroxy-3-nitro-4-chloropyridine from 4-hydroxy-3-nitropyridin-2(1H)-one: to 2,4-dihydroxy-3-nitropyridine (5.00 g, 0.032 mol), dimethyl chloride (4.07 g, 0.032 mol), and 5 drops of DMF were added to 2,4-dihydroxy-3-nitropyridine (5.00 g, 0.032 mol) and slowly added dropwise to dichloromethane (80 mL) at 0°C. . The reaction mixture was stirred at room temperature for 4 hours. After the reaction was complete, it was diluted by adding dichloromethane (100 mL). The organic layer was washed sequentially with saturated sodium bicarbonate solution, water and saturated saline. The organic layer was dried with anhydrous sodium sulfate, filtered and concentrated under reduced pressure to afford the target product 2-hydroxy-3-nitro-4-chloropyridine (5.00 g, 89% yield).
References
[1] Organic Process Research and Development, 2013, vol. 17, # 12, p. 1561 - 1567
[2] Patent: CN108498516, 2018, A. Location in patent: Paragraph 0023; 0025; 0026; 0027; 0028
[3] Patent: WO2017/14323, 2017, A1. Location in patent: Paragraph 0250
[4] Bioorganic and Medicinal Chemistry Letters, 2012, vol. 22, # 15, p. 4986 - 4989
[5] Patent: US2012/289497, 2012, A1. Location in patent: Page/Page column 29
