One-Pot Wittig and Knoevenagel Reactions in Ionic Liquid as Convenient Methods for the Synthesis of Coumarin Derivatives
作者:Hassan Valizadeh、Sevil Vaghefi
DOI:10.1080/00397910802573163
日期:2009.4.7
condensation, higher conversions were observed via Wittig reaction of these compounds with 2-hydroxybenzaldehyde derivatives and triphenylphosphine. Other 2-hydroxybenzaldehyde derivatives, methyl- and ethylchloroacetates, were reacted in ionic liquids to afford simple coumarins in good yields. These reactions widen the applicability of ionic liquid in organic synthesis.
摘要描述了通过 NaOMe 催化的 Knoevenagel 缩合高效合成多种 3-取代香豆素,以及在 NaOMe 存在下通过 Wittig 反应在室温离子液体中一锅法制备 3,4-未取代香豆素。2-羟基苯甲醛与丙二酸二甲酯和丙二酸二乙酯的 Knoevenagel 缩合在室温离子液体中以优异的收率进行。尽管氯丙二酸二乙酯和二甲基氯丙二酸酯在 Knoevenagel 缩合中大部分没有变化,但通过这些化合物与 2-羟基苯甲醛衍生物和三苯基膦的 Wittig 反应观察到更高的转化率。其他 2-羟基苯甲醛衍生物,氯乙酸甲酯和氯乙酸乙酯,在离子液体中反应,以良好的收率得到简单的香豆素。