The general procedure for the synthesis of 2-amino-5-nitro-6-chloropyridine from 2-amino-6-chloropyridine was as follows: concentrated nitric acid (2.39 mL, 35.00 mmol) was slowly added dropwise at 0 °C to a mixture containing concentrated sulfuric acid (56 mL, 1050 mmol) and 6-chloropyridin-2-amine (3.00 g, 23.34 mmol). The reaction mixture was kept stirred at 0 °C for 4 hours. After completion of the reaction, the mixture was carefully poured into ice water. The mixture was extracted with ethyl acetate (3 x 100 mL). The organic layers were combined, dried with anhydrous sodium sulfate and subsequently concentrated. The residue was purified by column chromatography to afford the target product 2-amino-5-nitro-6-chloropyridine (1.38 g, 34% yield).
