General method: α-Bromophenyl ketone derivative (1.34 mmol) was dissolved in formamide (10 mL) and the reaction was heated at 170-180°C for 5-10 hours. After completion of the reaction, the reaction solution was cooled to room temperature and diluted with saturated NaHCO3 solution (20 mL). Subsequently, the aqueous phase was extracted with ethyl acetate (3 x 50 mL). The organic layers were combined, washed sequentially with water and saturated brine and dried over anhydrous Na2SO4. The organic phase was concentrated under reduced pressure to obtain the crude product. Finally, the crude product was purified by silica gel fast column chromatography to obtain the target compound 5-(3-bromophenyl)-1H-imidazole.
