氯化胆碱催化合成香豆素-3-羧酸

香豆素衍生物合成方法的研究与改进已经成为国内外学者的热门研究方向。室温条件下,在水相中以水杨醛和麦氏酸为原料、氯化胆碱为催化剂、乙醇为辅助溶剂,通过Knoevenagal缩合-分子内环化串联反应以88%~96%的产率合成了一系列的香豆素-3-羧酸。该方法拓展了可用于合成香豆素-3-羧酸的催化剂的种类,具有反应条件温和、催化剂廉价易得、底物适用性广、产率较高、后处理简单和产物易于纯化等优点。

Choline Chloride Promoted Synthesis of Coumarin-3-carboxylic Acids

The synthesis of coumarin-3-carboxylic acids in a more convenient way has attracted considerable attention from organic and medicinal chemists. In this paper, a simple and effective method was described through a Knoevenagel-intramolecular cyclization tandem reaction of 2-hydroxyarylaldehydes with Meldrum's acid at room temperature. Employing commercially available, mild, and nontoxic choline chloride as the accelerant and using the mixture of water and ethanol as solvent is highly applicable to get a satisfactory outcome from 88% to 96%. This approach expands the method for the preparation of coumarin-3-carboxylic acids and also provides other advantages such as mild reaction conditions, tolerant the substrates with diverse functional groups, and simple post-treatment process.