Nano-TiCl4/SiO2: An efficient heterogeneous solid acid catalyst for the one pot cascade five-component synthesis of densely functionalized tetrahydropyridines

Nano-TiCl4/SiO2 was found to be an inexpensive and efficient heterogeneous solid acid catalyst for the synthesis of one-pot cascade synthesis of highly functionalized asymmetric tetrahydropyridines from the five-component condensation reaction of the para-substituted anilines and aromatic aldehydes with ethyl acetoacetate under thermal conditions. Novel methodology, environmentally benign conditions, clean protocol, easy work-up and high yields are the important advantages of this protocol. The products were characterized using physical and spectroscopic data such as FT-IR, H-1-NMR and in some cases C-13-NMR and CHN analysis.