Uses
N2-Methylpyridine-2,3-diamine is a useful reagent in synthesis of imidazopyridines, which show tuberculostatic activity.
Synthesis
General procedure for the synthesis of N2-methyl-2,3-pyridinediamine from N-methyl-3-nitropyridin-2-amine: N-methyl-3-nitropyridin-2-amine (58.14 g, 0.38 mol) was dissolved in 1,2-dimethoxyethane (400 mL) under vigorous stirring. Activated carbon (2.9 g) was added to the resulting solution, refluxed for 2 hours and left at room temperature overnight. After displacing the reaction system with dry nitrogen, 10% Pd/C catalyst (1.75 g) was added. The mixture was heated to 40 °C and hydrazine monohydrate (54 mL, 1.08 mol) was slowly added dropwise over a period of 2 hours. After dropwise addition, the reaction mixture was refluxed for 2 h. After cooling, the reaction mixture was filtered through a column of diatomaceous earth (upper layer, 3 cm) and silica gel (lower layer, 5 cm, 13 cm diameter) to remove the catalyst. The filtrate layer was washed with 1,2-dimethoxyethane (300 mL). The filtrate was concentrated under reduced pressure to afford N2-methyl-2,3-pyridinediamine in 98% yield (46.2 g) as a brown crystalline solid. The product could be used directly in the subsequent reaction without further purification.
References
[1] Chemistry - A European Journal, 2017, vol. 23, # 57, p. 14173 - 14176
[2] Open Medicinal Chemistry Journal, 2018, vol. 12, # 1, p. 74 - 83
[3] Patent: WO2008/12622, 2008, A2. Location in patent: Page/Page column 57
[4] Patent: CN106831776, 2017, A. Location in patent: Paragraph 0100; 0101; 0102
[5] Patent: WO2012/121936, 2012, A2. Location in patent: Page/Page column 93-94
