Synthesis
General procedure for the synthesis of 2-amino-3-phenylpyridine from 2-amino-3-bromopyridine and phenylboronic acid: to a solution of 2-amino-3-bromopyridine (3 mmol, 0.5 g) in ethylene glycol (5 mL) was added phenylboronic acid (4.5 or 9.0 mmol, 1.5 or 3 eq.), tetrakis(triphenylphosphine)palladium(0) (1 mol%) and potassium phosphate (6 mmol, 6 eq.) in sequence. 2 eq.) in water (2 mL). The reaction mixture was heated at 80 °C for 16 h. After completion of the reaction, it was hydrolyzed with 1 M sodium hydroxide solution (20 mL). The aqueous phase was extracted with ethyl acetate (3 x 30 mL) and the combined organic layers were washed with saturated sodium chloride solution (50 mL), dried over anhydrous magnesium sulfate, filtered and concentrated under reduced pressure. The residue was purified by silica gel column chromatography using petroleum ether/ethyl acetate (60/40, v/v) as eluent.
References
[1] Chemistry - A European Journal, 2013, vol. 19, # 28, p. 9137 - 9141
[2] Bioorganic and Medicinal Chemistry Letters, 2016, vol. 26, # 1, p. 114 - 120
[3] Bioorganic and Medicinal Chemistry Letters, 2017, vol. 27, # 4, p. 911 - 917
[4] Patent: WO2011/17342, 2011, A2. Location in patent: Page/Page column 116
[5] Patent: WO2015/148344, 2015, A2. Location in patent: Page/Page column 60
