Using 2-amino-4-bromopyridine (400 mg, 2.31 mmol) and trimethylsilylacetylene (0.38 mL, 2.77 mmol), bis(benzylcarbonitrile)dichloropalladium (II) was prepared in the presence of cesium carbonate (39.1 mg, 0.12 mmol) and 4,5-bis(diphenylphosphino)-9,9-dimethylx-ton (69.4 mg, 0.12 mmol). Palladium(II) chloride (46.0 mg, 0.12 mmol) was dissolved in DMF (5 mL). Subsequently, triethylamine (2 mL) was added and the reaction mixture was stirred at 50 °C in an oil bath for 2 hours. Upon completion of the reaction, THF (3 mL) and tetrabutylammonium fluoride (2.77 mL) were added, the solvent was concentrated under reduced pressure, and then the reaction was continued for 30 min at room temperature. Finally, the solvent was evaporated and the residue was purified by silica gel column chromatography using a solvent mixture of chloroform and methanol (1:50) as eluent to afford the target product 4-ethynylpyridin-2-amine (90.1 mg, 33% yield).
