Ionic Liquid–Mediated Synthesis of Coumarin-3-carboxylic Acids via Knoevenagel Condensation of Meldrum's Acid with <i>ortho</i>-Hydroxyaryl Aldehydes
作者:Nitin B. Darvatkar、Amol R. Deorukhkar、Sachin V. Bhilare、Dilip G. Raut、Manikrao M. Salunkhe
DOI:10.1080/00397910802162967
日期:2008.9.29
Abstract A simple, efficient, and green protocol for synthesis of coumarin-3-carboxylic acids is described via Knoevenagelcondensation of Meldrum's acid with ortho-hydroxyaryl aldehydes in [Hmim]Tfa ionic liquid, which was found to give better results than other ionic liquids. Furthermore, ionic liquid is easily reused without any appreciable loss in activity.
ZrOCl2 · 8H2O: An efficient catalyst for rapid one-pot synthesis of 3-carboxycoumarins under ultrasound irradiation in water
作者:Ghasem Bardajee、Farnaz Jafarpour、Hamid Afsari
DOI:10.2478/s11532-009-0141-9
日期:2010.4.1
In this report, a rapid, efficient and environmental friendly synthesis of 3-carboxycoumarins under ultrasoundirradiation in water media is described. The Knoevenagel condensation of Meldrum’s acid with substituted benzaldehydes in the presence of zirconium oxide chloride (ZrOCl2·8H2O) and ultrasonic irradiation in water gave the corresponding 3-carboxycoumarins in good to excellent yields.