Deep eutectic solvents (DES), a new generation ionic liquids, are green reactive media in organic synthesis, electrochemical, and biomass conversion. In this paper, we have developed a deep eutectic solvent [ethylene glycol]4[ZnCl2], simply prepared from choline chloride with ethylene glycol and used as a catalyst for the three-component reaction to synthesize propargylamine from available substrates including piperidine, phenylacetylene and benzaldehyde derivatives. The reaction mixture was activated by magnetic stirring and the optimization of conditions was investigated including temperature, time, catalytic mass, substrate effect and recycled catalyst. At 80 ◦ C, we successfully synthesized 5 propargylamine derivatives over a period of 180 minutes with high efficiency and only used 2% moles of catalyst. Desired products are structurally identified by NMR and MS (nuclear magnetic resonance 1H, 13C NMR and gas chromatography coupled mass spectrometry GC-MS). The results showed that DES [ethylene glycol]4[ZnCl2] catalyzed the efficiency of this reaction and the ability to reuse many times with negligible reduction in activity. Research to expand the scope of the substrate (heterocyclic oxygen and nitrogen compounds) and reaction mechanism are underway in the laboratory. Simple, efficient reaction processes have been the potential for industrial applications.
Cross-dehydrogenative coupling reaction using copper oxide impregnated on magnetite in deep eutectic solvents
