A solution of 5-(4-methylphenyl)isoxazole-4-carboxylic acid (20 mg, 0.1 mmol), TBTU (39 mg, 0.12 mmol, 1,2 equ.) and N-ethyl-N-isopropylpropan-2-amine (35 μL, 0.2 mmol, 2 equ) in DMF (1 mL) was added to 3-(4-fluorophenyl)-2,5-dihydro-1H-pyrrole hydrochloride (20 mg, 0.1 mmol) and the reaction mixture was left at rt for 2 h. The solvent was evaporated and the crude product was purified by RP-HPLC. After evaporation of the solvents the product was dried in vacuum to yield the title compound (11 mg). MS (ESI, pos. ion) m/z calcd for C21H17F N2O2: 348.1274, found 348.1266.
