A mixture of (E)-4-(4-(1-methylpyrrolidin-2-yl)benzylideneamino)isobenzofuran-1(3H)-one (0.32 g, 1 mmol), 4-fluorobenzenaldehyde (0.248 g, 2 mmol) was dissolved in dry ethyl propionate (5 mL), EtONa (0.136 g, 2 mmol) in EtOH (5 mL) was added to this solution and the mixture was stirred at room temperature until the starting material was disappeared as monitored by TLC. The reaction was quenched with 0.5 mL of water, the resulting mixture was concentrated in vacuo, and the residue was purified by column chromatography (MeOH:DCM=1:20) to give the title compound (200 mg, yield 42%) as a pale yellow solid. LC-MS (ESI) m/z: 472 (M+1)+.
