Supported l-tryptophan on Fe3O4@SiO2 as an efficient and magnetically separable catalyst for one-pot construction of spiro[indene-2,2′-naphthalene]-4′-carbonitrile derivatives

In this work, l-tryptophan functionalized silica-coated magnetic nanoparticles were readily prepared and evaluated as a recyclable magnetic nanocatalyst for the synthesis of spiro[indene-2,2 '-naphthalene]-4 '-carbonitrile derivatives through the one-pot four-component reaction of malononitrile, cyclohexanone, aromatic aldehydes, and 1,3-indandione. This novel magnetic nanocatalyst was confirmed to be effective and provide products in moderate to excellent yields under reflux conditions. The structure of obtained nanoparticles was characterized using FT-IR, XRD, VSM, EDX, elemental mapping, FE-SEM, and TGA. This synthetic protocol provides several benefits such as excellent yields in short reaction times (64-91%), saving costs, reusability of the catalyst using an external magnet (seven runs), and low catalyst loading.

Automated summary

In this work, l-tryptophan functionalized silica-coated magnetic nanoparticles were prepared and evaluated as a recyclable magnetic nanocatalyst for the synthesis of spiro[indene-2,2'-naphthalene]-4'-carbonitrile derivatives. The obtained nanoparticles showed effective catalytic activity and provided products in moderate to excellent yields under reflux conditions. Various characterization techniques were used to investigate the structure of the nanoparticles.