Supported <scp>l</scp>-tryptophan on Fe<sub>3</sub>O<sub>4</sub>@SiO<sub>2</sub> as an efficient and magnetically separable catalyst for one-pot construction of spiro[indene-2,2′-naphthalene]-4′-carbonitrile derivatives
Aref Ghasemi‐Ghahsareh, Javad Safaei‐Ghomi, Hourieh Sadat Oboudatian
Abstract
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.