A novel synthesis of 2-aryl-4-piperidones by mannich cyclization of iminoketals

One-Pot Synthesis of Substituted Piperidinones and 3,4-Dihydropyrimidinones Using a Highly Active and Recyclable Supported Ionic Liquid Phase Organocatalyst

1-Ethyl-3-methylimidazolium ethyl sulfate was synthesized and its supported ionic liquid phase form was prepared and used as an organocatalyst for the synthesis of substituted piperidinones and 3,4-dihydropyrimidinones. The ionic liquid was characterized by 1H NMR, 13C NMR, and mass spectrometry. The catalyst is novel, stable, completely heterogeneous, and recyclable for several times and can be easily recovered by filtration. It was characterized with scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, and energy-dispersive X-ray spectroscopy techniques. The workup procedures are very simple, and products were obtained in good-to-excellent yields with reasonable purities without the need for further chromatographic purification.