超声波辅助吗啡啉催化Knoevenagel缩合制备3-乙酰基香豆素

Morpholine Catalyzed Knoevenagel Condensation for the Synthesis of 3-Acetyl Coumarin under Ultrasonic Condition

摘要:

本研究发现吗啡啉能有效催化水杨醛和乙酰乙酸乙酯的Knoevenagel缩合制备3-乙酰基香豆素。探讨了溶剂、碱的种类、催化剂用量、反应时间等反应条件对3-乙酰基香豆素产率的影响，结果表明，以乙醇为溶剂，在超声波的辅助条件下，添加碳酸钠作为助催化剂，吗啡啉催化水杨醛和乙酰乙酸乙酯室温反应20 min即以91%的产率合成了3-乙酰基香豆素。采用NMR、IR表征了产物结构，并对反应催化机理进行了探讨。

Abstract:

Morpholine was found to be an effective catalyst for the synthesis of 3-acetyl coumarin through Knoevenagel condensation of 2-hydroxybenzaldehyde with ethyl acetylacetate. Reaction conditions such as solvent, base, catalyst loading, and reaction time were carried out to scrutiny. The results showed that under ultrasonic condition, 2-hydroxybenzaldehyde reacted with ethyl acetylacetate in ethanol at room temperature catalyzed by morpholine and Na2CO3, giving 3-acetyl coumarin after 20 min in 90% yield. The product was characterized with NMR and IR. A plausible catalytic mechanism was also proposed.