关键词: 2,2-亚戊基-1,3-二噁烷-4,6-二酮, 磷钨酸铈, 芳香醛, 缩合反应

Eight kinds of 5-alkenyl-2,2-pentamethylene-1,3-dioxane-4,6-diones were synthesized by the Knoevenagel condensation reaction of aromatic aldehydes with 2,2-pentamethylene-1,3-dioxane-4,6-dione using CePW₁₂O₄₀ as catalyst, without solvent under ultrasonic irradiation. The results indicate that the yields ranged from 87.6% to 94.1% when using 5% (molar fraction) CePW₁₂O₄₀ and reacting at room temperature for 20～35 min. Furthermore, a proposed reaction mechanism for the reaction catalyzed by CePW₁₂O₄₀ was speculated. Compared to the classical Knoevenagel condensation reaction, the main advantages of the present procedure were milder conditions, shorter reaction time and higher yields, which afforded an effective method to synthesize 5-alkenyl-isopropylidene malonate derivatines. Further study showed that CePW₁₂O₄₀ was environmentally friendly and reused for four times without any noticeable decrease in the catalytic activity.

Key words: 2,2-pentamethylene-1,3-dioxane-4,6-dione, CePW₁₂O₄₀, aromatic aldehydes, condensation reaction