Synthesis of N-methyl-3-nitropyridin-2-amine: methylamine (33% ethanol solution, 110 mL, 883 mmol) was added to a 500 mL three-necked round-bottomed flask and cooled to 0 °C in an ice bath. Under stirring, 2-chloro-3-nitropyridine (20 g, 126 mmol) was added in batches, and care was taken to control the dosing rate to alleviate the exothermic reaction. After the addition was completed, the reaction mixture was continued to be stirred at 0 °C for 2 h, followed by slow warming to room temperature and stirring for 1 h. The reaction was then concentrated under reduced pressure. Upon completion of the reaction, the solvent was removed by concentration under reduced pressure and the residue was dissolved in 500 mL of water and extracted with ethyl acetate (3 x 150 mL). The organic layers were combined, dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure to give the bright orange-yellow solid product N-methyl-3-nitropyridin-2-amine (19 g, 98.5% yield).
