L-Proline-functionalized magnetic nanocomposite: a green magnetic nanocatalyst for efficient synthesis of imidazo[1,2-a]pyridines

Nowadays, magnetic nanocatalysts have attracted much attention as beneficial strategy in green chemistry. Organocatalysis has received considerable attention in organic synthesis. Among all organocatalysts, proline has shown considerable catalytic efficiency in different organic synthesis due to easily accessible and available in both enantiomeric forms. Recently, much interest has been paid to the immobilization of organocatalyst onto magnetic nanoparticles for catalytic application in organic reactions. Imidazo[1,2-a]pyridines are an important class of nitrogen based heterocyclic compounds, which have been widely used in pharmaceutical industry due to their interesting biological activities. So far, several methods have been reported for the synthesis of these important frameworks. In continuation of our research, herein, an efficient and selective synthesis of imidazo[1,2-a]pyridine derivatives were carried out using aromatic aldehydes, 2-aminopyridines and trimethylsilyl cyanide (TMSCN) in the presence of a catalytic amount of L-proline-functionalized magnetic nanocatalyst (Fe₃O₄@L-proline) in ethanol at room temperature in high yields. The solid nanocatalyst can be recovered easily and reused without any significant loss of the catalytic activity.