General procedure: to a solution of DMF/MeOH (9:1, 4.0 mL) containing 3-ethynylpyridine (0.20 g, 1.94 mmol, 1.0 eq.), CuI (0.02 g, 0.097 mmol, 0.05 eq.) and trimethylsilyl azide (0.38 mL, 2.91 mmol, 1.5 eq.) were added in sequence. The reaction system was heated and stirred at 100 °C for 12 h under nitrogen protection. After completion of the reaction, it was cooled to room temperature, filtered through a diatomaceous earth pad and the filter cake was washed with EtOAc. The filtrates were combined and concentrated under reduced pressure to obtain the crude product. The crude product was purified by column chromatography (eluent: PE/EtOAc = 3:7, followed by pure EtOAc) and crystallized with EtOAc to afford the target compound 3-(1H-1,2,3-triazol-4-yl)pyridine (0.18 g, 64% yield) as a white solid. Melting point: 187-192 °C. 1H NMR (300 MHz, CD3OD) δ 9.03 (s, 1H), 8.51 (d, J = 3.7 Hz, 1H), 8.29-8.27 (m, 2H), 7.54-7.50 (m, 1H); 13C NMR (75 MHz, CD3OD) δ 148.3, 146.1, 143.1, 133.9, 127.3, 124.3; MS (ESI) m/z 147 [M + H]+; IR (KBr) 3467, 3118, 1637, 1560, 1434, 1311, 1134 cm-1. Calculated elemental values (C7H6N4): C, 57.53; H, 4.14; N, 38.34. Measured values: C, 57.67; H, 4.25; N, 38.10.
