A solution of 1,3-dibromo-5-chlorobenzene (10 g, 37.34 mmol), pyridine (6.03 mL) and copper(I) cyanide (3.34 g, 37.34 ) in DMF (57.74 mL) was refluxed under nitrogen for 2 days.
mmol) in DMF (57.74 mL) was refluxed under nitrogen for 2 days. The reaction was difficult to monitor by TLC and when impurities were observed, the reaction was cooled to room temperature.
The reaction mixture was quenched with 40 mL of ether, the precipitate was filtered and washed with ether (20 mL x 2).
The organic layer was washed with a mixture of water and concentrated ammonium hydroxide (2:1, 40 mL), saturated ammonium chloride solution (40 mL x 2) and saturated sodium bicarbonate solution (40 mL). .
The organic layer was dried over anhydrous sodium sulfate and concentrated. The residue was purified by column chromatography to afford the compound 3-bromo-5-chlorobenzonitrile (2 g, 25%).
