Design, synthesis and application of a magnetic H-bond catalyst in the preparation of new nicotinonitriles via cooperative vinylogous anomeric-based oxidation

Abstract

Herein, we designed and synthesized a new H-bond magnetic catalyst with 2-tosyl-N-(3-(triethoxysilyl)propyl)hydrazine-1-carboxamide as a sensitive H-bond donor/acceptor. We created an organic structure with a urea moiety on the magnetic nanoparticles, which can function as a hydrogen bond catalyst. Hydrogen bond catalysts serve as multi-donor/-acceptor sites. Additionally, we utilized magnetic nanoparticles in the production of the target catalyst, giving it the ability to be recycled and easily separated from the reaction medium with an external magnet. We evaluated the catalytic application of Fe₃O₄@SiO₂@tosyl-carboxamide as a new magnetic H-bond catalyst in the synthesis of new nicotinonitrile compounds through a multicomponent reaction under solvent-free and green conditions with high yields (50–73%). We confirmed the structure of Fe₃O₄@SiO₂@tosyl-carboxamide using various techniques. In addition, the structures of the desired nicotinonitriles were confirmed using melting point, ¹H-NMR, ¹³C-NMR and HR-mass spectrometry analysis. The final step of the reaction mechanism was preceded via cooperative vinylogous anomeric-based oxidation (CVABO).