General procedure: a mixed solution of 4-methoxy-3-nitropyridine (15.0 g, 97.3 mmol) and ethylamine (46.5 mL, 70% aqueous solution, 584 mmol) in ethanol (30 mL) was placed in a sealed flask and the reaction was stirred for 2 hr at 85 °C. After completion of the reaction, all volatiles were removed by distillation under reduced pressure to afford the target product 4-ethylamino-3-nitropyridine (16.2 g, 99% yield). The result of mass spectrometry analysis: (M + H)+ = m/z 168.
[1] Patent: WO2005/11700, 2005, A1. Location in patent: Page/Page column 84
[2] Patent: WO2005/46678, 2005, A1. Location in patent: Page/Page column 77
[3] Journal of Medicinal Chemistry, 2007, vol. 50, # 1, p. 2 - 5
[4] Patent: WO2008/71937, 2008, A1. Location in patent: Page/Page column 21