Methyl 2-ethynylisonicotinate

499193-51-0

1256810-92-0

Methyl 2-((trimethylsilyl)ethynyl)isonicotinate (8.00 g, 34.2 mmol) was used as the raw material, which was dissolved in THF (150 mL), and TBAF (1.0 M solution of THF, 51.4 mL, 51.4 mmol) was added slowly at 0°C. The reaction mixture was gradually warmed to room temperature and stirred continuously for 1 hour. After the reaction was completed, the reaction mixture was diluted with ethyl acetate (50 mL) and washed with 10% NaHCO3 solution (50 mL). The organic layer was separated, dried with anhydrous MgSO4 and concentrated under reduced pressure to give a dark brown to black residue. The residue was loaded on silica gel and purified by column chromatography (SiO2, eluent: 0-20% ethyl acetate/petroleum ether, 40-60°C) to afford the target product methyl 2-alkynylisonicotinate (4.5 g, 81% yield) as a yellow solid.1H NMR (400 MHz, CDCl3) δ 8.73 (dd, J = 5.1, 0.9 Hz, 1H), 8.01 (dd, J = 5.1, 0.9 Hz, 1H), 8.01 (dd, J = 5.1, 0.9 Hz). 8.01 (dd, J = 1.5, 0.9 Hz, 1H), 7.80 (dd, J = 5.1, 1.6 Hz, 1H), 3.95 (s, 3H), 3.22 (s, 1H).