To a flask containing tert-butyl 5-bromopicolinate 41-1 (1.55 g, 6.0 mmol), 2-(tributylstannyl)pyrazine 41-2 (2.21 g, 6.0 mmol) and Pd(PPh3)4 (426 mg, 0.6 mmol) under argon was added DMF (15 mL). The mixture was stirred at 120° C. for 10 hours. After cooling to room temperature, the mixture was diluted with ethyl acetate, washed with H2O and brine, dried over Na2SO4, and concentrated to dryness by rotary evaporation. The crude product was purified by silica gel flash chromatography, eluted with 5% methanol in dichloromethane to give tert-butyl 5-(pyrazin-2-yl)picolinate 41-3 as a pale yellow solid. MS m/z 258.1 (M+1)
