General procedure for the synthesis of 4-(4-bromophenyl)piperidine hydrochloride from 1-N-Boc-4-(4-bromophenyl)piperidine: To a solution of ethyl acetate (1 mL) containing 1-N-Boc-4-(4-bromophenyl)piperidine (1114 mg, 3.27 mmol) was slowly added a solution of ethyl acetate (2 mL) with 4 N hydrogen chloride at room temperature. The reaction mixture was stirred at room temperature for 5 h before the solvent was removed by distillation under reduced pressure. The resulting solid was washed with ethyl acetate and dried under vacuum to give 4-(4-bromophenyl)piperidine hydrochloride (884 mg, 98% yield) as a white solid.
