4093-88-3

5028-20-6

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.