Synthesis
Sodium methanolate (2.70 g, 50.0 mmol) was added batchwise to a stirred suspension of 4,6-dichloro-5-nitropyrimidine (4.85 g, 25.0 mmol) in methanol (90 ml) at 0 °C over 10 min. After addition, the reaction mixture was maintained at 0°C and continued to stir for 2 hours. After completion of the reaction, the precipitate was collected by filtration. The filtrate was concentrated to dryness and the resulting residue was suspended in isohexane and filtered again. The filtrate was concentrated and the residue was purified by rapid column chromatography on silica gel, using a 5% ethyl acetate solution in isohexane as eluent. The grades containing the target product were collected and concentrated to give 4-methoxy-5-nitro-6-chloropyrimidine (3.50 g, 74% yield) as a white solid.
References
[1] Patent: WO2004/41826, 2004, A1. Location in patent: Page 42
[2] Patent: EP2527344, 2012, A1. Location in patent: Page/Page column 34
[3] Patent: WO2012/160030, 2012, A1. Location in patent: Page/Page column 138-139
[4] Journal of Medicinal Chemistry, 1993, vol. 36, # 11, p. 1630 - 1640
