To a solution of 4-phenyl-1-pyrrolidin-3-yl-piperidine dihydrochloride (preparation #7) (0.050 g, 0.165 mmol) and triethylamine (0.092 mL, 0.66 mmol) in dichloromethane (1 mL) was added 1-isocyanatomethyl-4-methyl-benzene (0.024 g, 0.165 mmol) and the reaction mixture was stirred at ambient temperature for about 16 h. The reaction mixture was concentrated in vacuo and the residue was purified by flash chromatography on silica gel using 5% MeOH/EtOAc as the mobile phase to give 3-(4-phenyl-piperidin-1-yl)-pyrrolidine-1-carboxylic acid 4-methyl-benzylamide (0.042 g, 68%). RP-HPLC (Table 1, Method b) Rt 1.72 min; m/z: (M+H)+ 378.
