Highly Efficient Method for the Synthesis of Chalcones, Catalyzed by Fe3O4 Magnetic Nanoparticles (MNPs) Under Solvent-Free Reaction Conditions

Chalcones are useful groups of natural products that are potentially important synthetic intermediates for preparation of flavonoids and a series of heterocyclic compounds [1].A number of methods based on heterogeneous catalysts such as HClO4/SiO2 [2], TiO2 nanoparticles [3], and Fe3O4 MNPs [4] have been developed for the synthesis of chalcones, which usually required longer time, complex synthetic pathways and often expensive catalyst. Therefore, the search for new routes for the synthesis of chalcones has attracted considerable attention and the pursuance of more convenient and practical synthetic methods for these compounds still remains an active research area. Herein we have developed a simple and efficient method for the synthesis of chalcones using Fe3O4 magnetic nanoparticles (MNPs) towards the cross aldol condensation reactions of 4-chloroacetophenone, benzalacetone, tetralone, acetone and 3-penatanone (as ketones having enolizable methyl and methylene groups) with substituted aromatic aldehydes under solvent-free conditions at 90–110 °C (Figure 1). The experimental procedure is very simple, the products are formed in high yields and the catalyst is easily separated by applying an external magnetic field.