Synthesis
General procedure for the synthesis of 4-(bromomethyl)benzo[c][1,2,5]oxadiazole from 7-methyl-1H-benzo[D]imidazole: 7-methyl-1H-benzo[D]imidazole (13.4 g, 100 mmol) was dissolved in carbon tetrachloride (150 ml), N-bromosuccinimide (NBS, 23.5 g, 132 mmol) and benzoyl peroxide (Bz2O2, 0.29 g, 1.2 mmol). The reaction mixture was heated to 80-85 °C and kept for completion of the reaction. After completion of the reaction, the reaction system was cooled to 40 °C and concentrated under reduced pressure. The reaction mixture was filtered, the filter cake was washed with chloroform and the solvent was evaporated under reduced pressure to give the crude product (25.6 g). Purification by recrystallization from petroleum ether gave light yellow needle-like crystals of 4-(bromomethyl)benzo[c][1,2,5]oxadiazole (15.3 g) in 77.6% yield and melting point of 94-95 °C.
