Preparation and characterization of nano guar gum/BF3/Fe3O4 as a novel bio-based Lewis acid catalyst for the one-pot green synthesis of pyrimido benzothiazoles under solvent-free conditions

Abstract

Nano guar gum/BF₃/Fe₃O₄ is a bio-based nanocatalyst that was prepared, characterized and applied in one-pot three-component reactions of various aldehydes, 2-aminobenzothiazole and ethyl acetoacetate for the synthesis of 4H-pyrimido[2,1-b]benzothiazole derivatives at 80 °C under solvent-free conditions. The structure and properties of the heterogeneous bifunctional Lewis acid–base catalyst were studied via FT-IR, FESEM, TGA, EDS-MAP, XRD, VSM, and BET. Some unique characteristics of the magnetic nanocatalysts enabled the development of the catalytic activity using a simple, efficient, green and eco-friendly protocol. The catalyst was reused several times without a loss of activity.