The general procedure for the synthesis of 3-chloro-2-aminopyridine from 3-chloro-2-nitropyridine was as follows: 3-chloro-2-nitropyridine (1.00 g, 6.31 mmol) was dissolved in methanol (10 mL), and stannic(II) chloride (5.98 g, 31.54 mmol) and concentrated hydrochloric acid (2.63 mL, 31.54 mmol) were added sequentially. The reaction mixture was stirred at room temperature overnight. After completion of the reaction, the reaction solution was diluted with ethyl acetate and washed with 1N NaOH solution. Subsequently, the organic phase was washed with saturated NaHCO3 solution and dried with anhydrous Na2SO4. Finally, the organic phase was concentrated under reduced pressure to afford the target product 3-chloro-2-aminopyridine (510.0 mg, 63% yield). The product was characterized by 1H NMR (400 MHz, CD3CN) with chemical shifts of δ 6.80 (m, 1H), 7.60 (d, 1H), 8.12 (d, 1H).
