GENERAL METHODS: 5 mmol of p-hydroxybenzaldehyde was added to a round-bottomed flask with 5 mmol of ethyl cyanoacetate, 25 mg of polymer-loaded catalyst (0.5 mol% substrate) and 5 mL of anhydrous ethanol, and the reaction was stirred at room temperature. The reaction process was monitored by silica gel thin layer chromatography (TLC) with hexane-ethyl acetate (10:1) as eluent. Upon completion of the reaction, the reaction mixture was filtered using filter paper and the catalyst on the filter paper was washed several times with ethanol. The washings and filtrates were combined and the product was isolated after concentration under reduced pressure. Typically, the products were of high purity and did not require further purification. All the products were reported in literature and characterized by melting point determination, Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance hydrogen spectroscopy (1H NMR).
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