A highly efficient and recyclable cobalt ferrite chitosan sulfonic acid magnetic nanoparticle for one-pot, four-component synthesis of 2H-indazolo[2,1-b]phthalazine-triones

Abstract

A highly efficient magnetic CoFe₂O₄ chitosan sulfonic acid nanoparticle (CoFe₂O₄-CS-SO₃H) was prepared and applied for one-pot, four-component synthesis of 2H-indazolo[2,1-b]phthalazine-triones by condensation of phthalic anhydride, hydrazinium hydroxide, 1,3-cyclohexanedione and aldehydes under solvent-free conditions at 80 °C. The magnetic nanocatalyst could be readily recovered by applying an external magnet and recycled several times without significant loss of its catalytic activity.