The effective role of reusable Mn(III) Schiff-base nano-catalyst in carrying out Chromene & Biginelli reactions under eco-friendly conditions

Abstract

The development of efficient and recyclable catalysts is crucial for sustainable organic synthesis. A magnetic heterogeneous catalyst containing Mn(III) Schiff base covalently attached to Fe3O4@SiO2 nanoparticles through imidazolium linker [Fe3O4@SiO2-S-Im(Br)-SB-Mn(III)] was synthesized. The prepared nano-catalyst was characterized using various analytical methods (FT-IR, EDX, SEM, TEM, XRD, VSM, TGA, ICP-OES, and AAS). The efficiency of the nano-catalyst was investigated in the Chromene & Biginelli reactions using a one-pot threecomponent synthesis of 2-amino-tetrahydro-4H-chromene-3-carbonitrile and 3,4-dihydropyrimidine-2(1H)- ones/thiones derivatives. The catalyst was found to be highly efficient in the synthesis of these derivatives in water and solvent-free conditions. The results demonstrated that the products were synthesized with excellent yields (98 %) within 5–10 min under very mild conditions. The nano-catalyst was re-used for eight consecutive cycles without any significant loss of catalytic activity