Synthesis
Preparation of 2-chloro-3-nitro-6-phenylpyridine: To an anhydrous 1,4-dioxane solution of 2,6-dichloro-3-nitropyridine (1.00 g, 5.18 mmol) was added phenylboronic acid (0.695 g, 5.70 mmol), cesium carbonate (2 M aqueous solution, 7.5 mL, 15 mmol) and tetrakis(triphenylphosphine)palladium (0.025 g, 0.02 mmol). The reaction mixture was displaced three times with nitrogen and heated in a microwave reactor at 100 °C for 10 min. After completion of the reaction, it was cooled to room temperature and the reaction solution was poured into water and extracted with ethyl acetate. The organic phases were combined, washed sequentially with water and saturated saline, dried over anhydrous magnesium sulfate, filtered and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography (eluent: 5% ethyl acetate/hexane) to afford the target compound 2-chloro-3-nitro-6-phenylpyridine (0.5 g, 41% yield). LC-MS (m/z): 235 [M+H]+.
