Fabrication and characterization of inorganic–organic hybrid copper ferrite anchored on chitosan Schiff base as a reusable green catalyst for the synthesis of indeno[1,2-b]indolone derivatives

Abstract

This study presents a description of the catalytic synthesis of indeno[1,2-b]indolone derivatives. In this method, initially, a Schiff base compound was synthesized from the reaction of acetylacetone with 2-hydroxyaniline. Then, the prepared Schiff base was immobilized on chelated magnetic copper ferrite nanoparticles with a chitosan surface to design and prepare the CuFe₂O₄@CS-SB nanocomposite. Further, the one-pot multi-component cyclization reaction of aniline, dimedone and ninhydrin was conducted using the synthesized nanocomposite as a heterogeneous acid catalyst in water solvent under thermal conditions. In this reaction, the products were obtained in excellent yields and short reaction times, and the catalyst could be recycled and reused six times without any loss in product yields. By conducting FT-IR spectroscopy, ¹H NMR spectroscopy, XRD, FE-SEM, TGA, elemental mapping scanning, EDX and BET analyses, the structure of the nanocatalyst was characterized. In addition, for the identification of organic compounds, FT-IR, ¹H NMR, and ¹³C NMR spectroscopies and melting point analysis were used, which confirmed the synthesis of this class of derivatives.