A mixed solution of terephthalaldehyde (10 g, 74.55 mmol) and ammonium chloride (160 mg, 3.0 mmol) in ethanol (10.3 g, 223.6 mmol) was added slowly and dropwise to the reaction flask at 0 °C. Subsequently, triethyl orthoformate (12.15 g, 82 mmol) was added dropwise to the reaction system. The reaction mixture was stirred at room temperature overnight. Upon completion of the reaction, the mixture was concentrated and the residue was purified by silica gel column chromatography to afford the target product terephthalaldehyde diethyl acetal (7.0 g, 50% yield) as a white solid.LC-MS (ESI) m/z: 209 (M + 1)+.
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