Ultrasound Probe-assisted Telescopic One-pot Synthesis of Spiro[indene-2,2'-naphthalene]-4'-carbonitrile Derivatives using Fe3O4@SCH2CO2H@Ni-NH2 as a Reusable Nanocatalyst

In this paper, a novel inorganic-organic hybrid catalyst based on Fe3O4 has been successfully developed during four simple steps. After construction of Fe3O4@SCH2CO2H, the presence of nickel and urea converts this catalyst into the porous nano magnetic catalyst. The prepared nanocatalyst was identified by FT-IR, VSM, XRD, FE-SEM, EDX, elemental mapping, TGA, TEM, and BET. Then, we have employed the prepared catalyst as a recoverable heterogeneous and nanoporous catalyst for synthesis of spiro[indene-2,2'-naphthalene]-4'- carbonitrile derivatives via one-pot telescopic four component reaction of malononitrile, cyclohexanone, aromatic aldehydes, and 1,3-indandione under ultrasonic irradiation. As anticipated, prepared catalyst displayed significant performance in the promoting of the studied reaction. Eco-friendly, facile workup, medium to excellent yields in short reaction times, broad range of products, high catalytic performance and reusability of the catalyst are some of the noticeable advantages of this protocol. Further, we can separate and reuse the catalyst six times without any significant loss of activity.

Automated summary

In this study, a novel inorganic-organic hybrid catalyst based on Fe3O4 was successfully developed through four simple steps. The catalyst was converted into a porous nano magnetic catalyst by the presence of nickel and urea after constructing Fe3O4@SCH2CO2H. Various characterization techniques confirmed the identity of the prepared nanocatalyst. The catalyst was employed as a recoverable heterogeneous and nanoporous catalyst for the synthesis of spiro[indene-2,2'-naphthalene]-4'-carbonitrile derivatives, showing significant performance and reusability.