Cerium-enriched magnetic/recyclable dual-acid nanocatalyst for one-pot three-component synthesis of functionalized 1,5-benzodiazepines

Cerium enriched magnetic dual-acid nanocatalyst (CoFe2O4@SiO2@APTES@ATA-CeCl3) as green and recoverable nanocatalyst was prepared. The novel nanocatalyst was characterized by Fourier transform infrared spectroscopy (FT-IR), powder X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), inductively coupled plasma atomic emission spectrometry (ICP-AES), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), nitrogen absorption-desorption experiment, and vibrating sample magnetometer (VSM). The dual-acid nanocatalyst was able to efficiently catalyze the synthesis of functionalized 1,5-benzodiazepines following through a three-component domino reaction of various substituted o-phenylenediamine, 1,3-dicarbonyl compounds, and phenylacetaldehyde. The dual-acid sites of Bronsted acid (2-aminoterephthalic acid (ATA)) and Lewis acid (CeCl3) of the catalysts were determinant features. Furthermore, a plausible catalytic mechanism has been proposed. The dual-acid nanocatalyst can be simply separated and reused without any remarkable decrease within the yield after six runs.