To a 50 mL round-bottomed flask was added 5-chloro-4-(1,4-dimethyl-1H-pyrazol-5-yl)-2-thiophenecarboxylic acid (96 mg, 0.37 mmol), 2-[(2S)-2-amino-3-(2,5-difluorophenyl)propyl]-1H-isoindole-1,3(2H)-dione (125 mg, 0.40 mmol) [prepared according to the procedure of Preparation 18 except substituting 2,5-difluoro-L-phenylalanine (3.02 g, 15.0 mmol) for 2,6-difluoro-L-phenylalanine] and PyBrop (225 mg, 0.48 mmol) in chloroform (4 mL). DIEA (330 μL, 1.89 mmol) was added and the reaction stirred overnight at room temperature. The mixture was adsorbed onto silica and purified via column chromatography (25-70% EtOAc/Hex) affording the title compound (98 mg, 0.13 mmol, 34%): LC-MS (ES) m/z=535 (M+H)+.
