High Catalytic Activity, Recyclable and Magnetically Separable Nanocatalyst Fe3O4@SiO2-Schiff base-Pd(II) for Synthesis of 12H-Benzo[5,6]Chromeno[2,3-b]Pyridine-10-Carbonitriles and Evaluation of Antibacterial Activity

In this work, an effective and selective heterogeneous catalyst was produced by immobilization of palladium Schiff base-complexes on ferrite magnetite nanoparticles (MNP). The catalysts Fe₃O₄@SiO₂-Schiff base-Pd(II) were synthesized using Fe₃O₄@SiO₂ core–shell nanoparticles and functionalized with 3-chloropropyltrimethoxysilane (CPTMS) as Fe₃O₄@SiO₂@Cl. The Schiff base ligand was synthesized by reaction of 2-hydroxy-1-naphthaldehyde with 4-aminophenol to produce of 1-(((4-hydroxyphenyl)imino)methyl)naphthalen-2-ol, then palladium acetate was added to produce of Schiff-base-Pd(II) complex. Finally, Fe₃O₄@SiO₂-Schiff base-Pd(II) was synthesized by the reaction of Fe₃O₄@SiO₂@Cl core–shell nanoparticles with Schiff-base-Pd(II). The catalyst was characterized by several techniques, such as FT-IR, TEM, EDX, XRD, TGA and VSM. An efficient tandem reaction approach is described to prepare novel 12H-benzo[5,6]chromeno[2,3-b]pyridine-10-carbonitrileusing 1 mol% catalyst in methanol. The described one-pot three-component reaction is characterized by short reaction time, high product yield, mild reaction conditions, simple workup procedure, simple purification and catalyst can be easily recovered and reused in at least seven sequential cycles without considerable leaching and loss of reactivity