[Synthesis]
Under argon protection, 1.0 g (7 mmol, 1 eq.) of 2-chloro-5-methylpyridin-3-amine was dissolved in 15 mL of anhydrous N,N-dimethylformamide (DMF) in a 20 mL reaction vial. Subsequently, 821 mg (7 mmol, 1 equiv) of zinc cyanide (Zn(CN)2) was added. After degassing the reaction system for 10 min, 405 mg (0.35 mmol, 0.05 eq.) of tetrakis(triphenylphosphine)palladium(0) (Pd(PPh3)4) was added. The reaction mixture was heated to 105 °C and the reaction was stirred at this temperature for 20 hours. After completion of the reaction, the mixture was filtered through diatomaceous earth and the filtrate was concentrated under reduced pressure. The crude product was purified by silica gel column chromatography (eluent: ethyl acetate/petroleum ether, 2/8, v/v) to afford the white solid target product 3-amino-2-cyano-5-methylpyridine in 65% yield. The melting point of the product was 154 °C. Infrared spectrum (diamond ATR, cm^-1) ν: 3404, 2216, 1600, 1465, 1339, 1230, 858, 739; 1H NMR (400 MHz, CDCl3) δ: 2.34 (s, 3H, CH3), 4.37 (br s, 2H, NH2), 6.93 (d, 1H, J = 2.4 Hz. Harom), 7.93 (d, 1H, J = 2.4 Hz, Harom); 13C NMR (101 MHz, CDCl3) δ: 28.7 (CH3), 114.9 (CH), 116.3 (CN), 122.6 (CH), 138.6 (Cq), 142.2 (CH), 146.3 (Cq). |