A novel and efficient boron-containing magnetic catalyst based on graphene oxide (GO-Fe3O4-BFn) for synthesis of pyrazole and pyranopyrazole derivatives

Abstract

The creation of non-toxic acidic catalysts has benefited greatly from the immobilization of acidic materials on solid substrates. In the present work, a novel and capable magnetically Lewis acid catalyst based on graphene oxide (GO) was introduced for the synthesis of pyrazole derivatives. The new catalyst was prepared as a heterogeneous Lewis acid composite by immobilization on BF3 on GO-Fe3O4. The magnetic and recoverable catalyst was characterized by FT-IR (Fourier‑Transform Infrared Spectroscopy), FESEM (Field Emission Scanning Electron Microscopy), XRD (X‑Ray Diffraction), EDS (Energy-Dispersive X-Ray Spectroscopy), ICP (Inductively Coupled Plasma), VSM (Vibrating Sample Magnetometer) and TGA (Thermogravimetry Analysis) techniques. Catalytic activity of the GO-Fe3O4–BFn checked out in the synthesis of pyrazole (3a-3f) and 2,4-dihydropyrano[2,3-c] pyrazole (8a-8f) derivatives under mild conditions. Pyrazole and pyranopyrazol derivatives were synthesized in desirable yield in the presence of our new catalyst. High surface area, chemical and thermal stability, good selectivity, high reactivity with easily magnetically separation are some of advantageous of our catalyst. The catalyst can also be recycled for several times without reducing its catalytic efficiency. Furthermore, molecular docking studies were performed to predict the interaction mode of the synthesized compounds toward the EGFR kinase as a possible target.