Synthesis
5-Bromo-4-methyl-3-nitropyridin-2-amine (700.0 mg, 3.02 mmol) was added with iron powder (1680.0 mg, 30.20 mmol) and concentrated hydrochloric acid (50.0 μL) in a solvent mixture of ethanol (2.8 mL) and water (0.7 mL). The reaction suspension was stirred at 100 °C for 30 min. Upon completion of the reaction, the mixture was cooled to room temperature and filtered through diatomaceous earth to remove insoluble impurities. The filtrate was concentrated by distillation under reduced pressure and the resulting residue was purified by silica gel column chromatography (eluent: methanol/dichloromethane = 1:40). The grades containing the target product were collected and the solvent was removed by evaporation to give 5-bromo-4-methylpyridine-2,3-diamine as a brown solid (550.0 mg, 90% yield). The product was analyzed by LCMS ESI (+): m/z 202 ([M + H]+), 204 ([M + H + 2]+). 1H-NMR (300 MHz, DMSO-d6) data: δ 7.37 (s, 1H), 5.49 (s, 2H), 4.74 (s, 2H), 2.12 (s, 3H).
References
[1] Patent: US2014/315888, 2014, A1. Location in patent: Paragraph 0842-0844
[2] Journal of Medicinal Chemistry, 2018, vol. 61, # 7, p. 2949 - 2961
[3] Journal of Medicinal Chemistry, 2010, vol. 53, # 22, p. 7958 - 7966
[4] Journal of the American Chemical Society, 1957, vol. 79, p. 6421,6423,6424
[5] Bioorganic and Medicinal Chemistry Letters, 1996, vol. 6, # 22, p. 2749 - 2754
