A solution of 3,5-bis(trifluoromethyl)benzoyl chloride (0.058 mmol) in dichloromethane (1 mL) was added to a mixture of 1-{4-chlorobenzyl)-4-((glycylamino)methyl}piperidine (0.050 mmol) and piperidinomethylpolystyrene (58 mg) in chloroform (0.2 mL) and dichloromethane (0.75 mL). After the reaction mixture was stirred at room temperature for 2 h, methanol (1.0 mL) was added and the mixture was stirred at room temperature for 30 min. The reaction mixture was loaded onto Varian™ SCX column, and washed with CH3OH (16 mL). Product was eluted off using 2 N NH3, in CH3OH (6 mL) and concentrated to afford 1-(4-chlorobenzyl)-4-[{N-(3,5-bis(trifluoromethyl)benzoyl)glycyl}aminomethyl]piperidine (Compound No. 1213) (24.0 mg, 90%): The purity was determined by RPLC/MS (100%); ESI/MS m/e 536.2 (M++H, C24H24ClF6N3O2).
