A 25 ml round-bottom tube is charged with (2R,4S)-4-[(3,5-bis-trifluoromethyl-benzyl)-(5-bromo-pyrimidin-2-yl)-amino]-2-ethyl-pyrrolidine-1-carboxylic acid tert-butyl ester (480 mg, 0.8 mmol), imidazole (82 mg, 1.2 mmol), CuI (152 mg, 0.8 mmol), K2CO3 (221 mg, 1.3 mmol), N,N-dimethyl glycine (82 mg, 0.8 mmol), and DMSO (4 ml). Then the tube is sealed and heated to 110 degree for 18 hours. After cooling to rt, saturated NH3/H2O and EtOAc are added and then filtered through Celite pad. The solution is extracted with EtOAc and organic layer is dried over MgSO4. Removal of solvent under reduced pressure and purification with reverse phase column give product (163 mg, 0.27 mmol, 35%). ESI-MS m/z: 585 [M]+, Retention time 2.07 min (condition A).
