2-Amino-5-nitropyridine CAS 4214-76-0 is derived from the nitration of 2-aminopyridine. At a temperature of 50 °C, 2-aminopyridine was added to concentrated sulfuric acid, and then fuming nitric acid was added dropwise, and the temperature did not exceed 50 °C. Incubate at 45°C for 2h, and stir at room temperature for 4h. The reaction solution was poured into crushed ice, and the pH was adjusted to 6 by adding ammonia water below 5°C, and crystals were precipitated. Filter and dry. Recrystallization with water to obtain pale yellow platelets, yield 75%