5-Ethynyl-2,2'-bipyridine

187026-84-2

162318-34-5

General procedure for the synthesis of 5-alkynyl-2,2'-bipyridines from 5-trimethylsilylethynyl-2,2'-bipyridines: 5-[(trimethylsilyl)ethynyl]-2,2'-bipyridine (0.360 g, 1.43 mmol) was dissolved in 30 mL of THF (pre-gassed with N2). Subsequently, a methanol (30 mL) solution of KOH (0.320 g, 5.72 mmol) was added. The reaction mixture was stirred at room temperature for 6 hours. Upon completion of the reaction, the solvent was removed by distillation under reduced pressure. The residue was purified by fast silica gel column chromatography using dichloromethane as eluent. The product yield was 95% (245 mg). Thin layer chromatography (TLC, SiO2) showed an Rf value of 0.45 (10% methanol/dichloromethane). Infrared spectroscopy (IR, KBr, cm-1 ) showed characteristic absorption peaks: 3298 (C≡CH), 3190 (C≡CH), 3049 (Ar-H), 3001 (Ar-H), 2964 (Ar-H), 2933 (Ar-H), 2096 (C≡C).1H NMR (400 MHz, CDCl3) δ 3.29 (s, 1H , C≡CH), 7.26-7.33 (m, 1H, PyH), 7.79-7.84 (m, 1H, PyH), 7.88-7.90 (m, 1H, PyH), 8.37-8.41 (m, 2H, PyH), 8.67-8.69 (m, 1H, PyH), 8.77 (m, 1H, PyH). Mass spectra (MS/EI) showed m/z 180 [M+, 100%], 153 [M+-NCH, 48%], 126 [M+-2(NCH), 9%].