General procedure for the synthesis of 5-alkynylpyridin-2-amines from 2-amino-5-[(trimethylsilyl)ethynyl]pyridines: To a mixed solution of 5-trimethylsilyl ethynyl-pyridin-2-ylamine (26 mg, 137 μmol) described in Preparation Example 28-1-2 in tetrahydrofuran (1 mL) and methanol (1 mL) was added potassium carbonate (37.9 mg, 274 μ mol). The reaction mixture was stirred at room temperature for 1 hour. Upon completion of the reaction, the reaction solution was partitioned into water and ethyl acetate at 0 °C for extraction. The organic layer was washed with saturated aqueous sodium chloride solution and dried with anhydrous magnesium sulfate. The solvent was removed by concentration under reduced pressure and the residue was purified by silica gel column chromatography (eluent: heptane/ethyl acetate=1:1) to afford the target product 5-alkynylpyridin-2-amines (16 mg, 99% yield).1H-NMR (CDCl3) δ (ppm): 3.07 (1H, s), 4.73 (2H, brs), 6.46 (1H, d, J=8.6 Hz). 7.53 (1H, dd, J=2.2,8.6 Hz), 8.21 (1H, s).
