4-Cyanobenzyl bromide

4-Cyanobenzyl bromide is an important intermediate for pharmaceutical production. It can be used for the synthesis of a series of piperidine-linked aromatic diimidazolines, which have been synthesized as conformationally restricted congeners of the anti-Pneumocystis carinii (PCP) drug, Pentamidine.

4-Cyanobenzyl bromide (C8H6BrN, CAS registry No. 17201-43-3) is a white solid. Its melting point is 113-117°C, and flash point is 125.1°C. It is insoluble in water at 20°C. It is stable under normal temperatures and pressures. It should be stored at 0-5°C.

874-89-5

17201-43-3

GENERAL METHOD: Hydroxymethyl (1 mmol) and potassium bromide (1.5 mmol, 0.18 g) were dissolved in ethanol (5 mL) and phosphorus pentoxide (1.5 mmol, 0.23 g) was added. The reaction mixture was stirred at room temperature until the reaction was complete (monitored by TLC or GC). After completion of the reaction, the mixture was filtered and the residue was washed with ethyl acetate (3 x 8 mL). The organic layers were combined, washed with water (10 mL) and dried over anhydrous sodium sulfate. The solvent was removed by concentration under reduced pressure to give the crude 4-cyanobenzyl bromide product. If further purification is required, column chromatography can be used.