Tannic Acid‐Functionalized Silica Coated Fe3O4 Nanoparticles as a Novel and Magnetically Separable Catalyst for Green Synthesis of Aryl Naphtho[1,3]Oxazine-2-Thiones

Abstract

Tannic acid‐functionalized silica‐coated Fe3O4 nanoparticles (Fe3O4@SiO2@Tannic acid) were synthesized and characterized by Transmission Electron Microscope (TEM), Field Emission Scanning Electron Microscope (FE-SEM), Fourier Transform Infrared Spectroscopy (FT-IR), Vibrating sample magnetometry (VSM), X-ray powder diffraction (XRD) and X-ray spectroscopy (EDS). Fe3O4@SiO2@Tannic acid supply an environmentally friendly procedure for the synthesis of 1,3-oxazine-2-thiones through three-component grinding reaction of various aldehydes, thiourea, and α-naphthol or β-naphthol in accordance with green chemistry rules. In the other study, this novel synthesized magnetically reusable catalyst was introduced as a new avenue for the synthesis of Aryl naphtho[1,3]oxazine-2-thione using the reaction between synthetized azo-linked aldehydes, malononitrile, and phenylhydrazine or p-tolylhydrazine. These compounds were obtained in high yields and short reaction times. The catalyst could be easily recovered and reused for six cycles with almost consistent activity. The structures of the synthesized Aryl naphtho[1,3]oxazine-2-thione compounds were confirmed by 1H NMR, 13C NMR and FTIR spectral data and elemental analyses.