LiAl-LDH: a heterogeneous catalyst for the multicomponent synthesis of coumarin-3-carboxamide derivatives

A series of coumarin-3-carboxamides were synthesized via a three-component reaction involving salicylaldehyde, aliphatic primary/secondary amines, and diethylmalonate. Li–Al containing layered double hydroxides were utilized as an eco-friendly heterogeneous catalyst in this process. The materials were prepared using a straightforward co-precipitation method and were thoroughly characterized using techniques such as X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and energy dispersive spectroscopy. The catalysts exhibited commendable performance, attaining product yields of up to 90% in an ethanol environment. Moreover, the layered double hydroxide catalysts can be efficiently recovered and recycled up to four times without substantial loss of catalytic activity. This method offers the advantages of a simple and clean synthetic route, easy work-up and waste minimization.