To the microwave reaction tube were added 3-amino-5-bromopyridine (0.400 g, 2.31 mmol), 3-fluorophenylboronic acid (0.356 g, 2.54 mmol), tetrakis(triphenylphosphine)palladium(0) (0.133 g, 0.116 mmol), potassium phosphate (0.736 g, 3.47 mmol), water (1 mL) and N,N-dimethylformamide (5 mL). The reaction tube was sealed and the air in the tube was replaced with argon, then placed in a microwave reactor and radiantly heated at 180°C for 1 hour. After completion of the reaction, the reaction mixture was filtered through a diatomaceous earth pad and the filtrate was concentrated under reduced pressure. The resulting crude product was purified by silica gel column chromatography with an eluent gradient of ethyl acetate/hexane (4:6→7:3, v/v) to afford 5-(3-fluorophenyl)pyridin-3-amine (0.360 g, 1.92 mmol, 83% yield) as a yellow-white solid. Electrospray ionization mass spectrometry (ESIMS) analysis showed that the molecular weight of the product was as expected (C11H9FN2, m/z 189.1 [M+H]+).
