Synthesis
The general procedure for the synthesis of 4-amino-3-nitropyridine from 4-aminopyridine was as follows: pyridin-4-amine (5.0 g, 50.0 mmol) was dissolved in concentrated sulfuric acid (20 mL) under ice-bath conditions. Keeping the reaction temperature in the range of 0-10 °C, fuming nitric acid (2.5 mL) was added slowly and dropwise. After the dropwise addition, the reaction was continued to be stirred at 0-10 °C for 5 hours. Subsequently, the reaction mixture was warmed to room temperature and heated at 90°C for 3 hours. After the reaction was completed, the mixture was continued to be stirred at room temperature overnight. The reaction mixture was slowly poured into ice water and the pH was adjusted with ammonia to 7. The resulting precipitate was collected by filtration and dried under reduced pressure to afford 4-amino-3-nitropyridine as a yellow solid (5.1 g, 70% yield). Mass spectrometry analysis showed [M + H]+ m/z: 140.04.
References
[1] Bioorganic and Medicinal Chemistry, 2018, vol. 26, # 9, p. 2621 - 2631
[2] Synthesis, 2011, # 5, p. 794 - 806
[3] Chemistry of Heterocyclic Compounds, 2015, vol. 51, # 2, p. 203 - 204
[4] Khim. Geterotsikl. Soedin., 2015, vol. 51, # 2, p. 203 - 204,2
[5] Patent: WO2017/168333, 2017, A1. Location in patent: Page/Page column 16
