A mixture of 4-[(5E)-5-(6-fluoro-2-oxo-1,2-dihydro-3H-indol-3-ylidene)-2,2-dimethyl-2,5-dihydrofuran-3-yl]benzaldehyde (55 mg, 0.16 mmol), 2-(2-(piperazin-1-yl)ethoxy)ethanol (56 mg, 0.32 mmol) and 4 Å molecular sieves (100 mg) in anhydrous DMF (3 mL) was stirred at room temp for 16 hours. To this stirred mixture was added AcOH (10 mg), 1M sodium cyanoborohydride in THF solution (0.32 mL, 0.32 mmol) and 3 mL of anhydrous methanol. The reaction mixture was stirred at room temp for 5 hours and poured into 100 mL of water. Saturated NaHCO3 solution was then added until pH=9. The precipitates were filtered, washed with water, and dried in vacuo to give the crude product, which was purified through silica gel column with 5-10% MeOH/CHCl3 to give (3E)-6-fluoro-3-{4-[4-({4-[2-(2-hydroxyethoxy)ethyl]piperazin-1-yl}methyl)phenyl]-5,5-dimethylfuran-2(5H)-ylidene}-1,3-dihydro-2H-indol-2-one as yellow solid. Yield: 45 mg, 56%.
