SnCl4/c-Al2O3 nanoparticles: A reusable and green heterogeneous catalyst for the one-pot synthesis of tetrahydropyridines

Nano-SnCl4/y-Al2O3 as a reusable and green heterogeneous catalyst was prepared by the reaction of tin tetrachloride with y-alumina. This solid acid catalyst was characterized by fourier transform-infrared spectroscopy (FT-IR), X-ray diffraction (XRD), field emission scanning elec-tron microscopy (FESEM), transmission electron microscopy (TEM), energy-dispersive X-ray spec-troscopy (EDS), thermal gravimetric analysis (TGA) and Brunauer-Emmett-Teller (BET) analyses. Tetrahydropyridines were synthesized via the one-pot reaction of 4-substitutd anilines, ethylace-toacetate and 4-substituted aldehydes in the presence of optimized amount (0.06 g) of nano-SnCl4/y-Al2O3 under thermal conditions (70 & DEG;C) in ethanol as a green solvent. The process had short reaction times (5-8 h), good to excellent yields (80-93%), simple work-up and easy purifica-tion technique (recrystallization through the hot ethanol). It was found that the catalyst could be reused for three times without any considerable loss of its activity. & COPY; 2023 The Author(s). Published by Elsevier B.V. on behalf of King Saud University. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Automated summary

Nano-SnCl4/y-Al2O3 was prepared as a reusable and green heterogeneous catalyst through a reaction between tin tetrachloride and γ-alumina. The catalyst was characterized by various techniques, such as FT-IR, XRD, FESEM, TEM, EDS, TGA, and BET analyses. Tetrahydropyridines were synthesized efficiently using the optimized amount of nano-SnCl4/y-Al2O3 under thermal conditions in ethanol as a green solvent. The catalyst showed good activity, short reaction times, high yields, and could be reused multiple times without significant loss of activity.