Synthesis of quinoxaline, benzimidazole and pyrazole derivatives under the catalytic influence of biosurfactant-stabilized iron nanoparticles in water

We have reported the synthesis, characterization, and catalytic applications of amorphous iron nanoparticles (FeNPs) using aqueous leaves extract of renewable natural resource Boswellia serrata plant. Synthesized FeNPs were stabilized in situ by the addition of aqueous pod extracts of Acacia concinna as a biosurfactant (pH 3.11). The structural investigation of biosynthesized nanoparticles was performed using UV–visible spectroscopy, X-ray diffraction analysis, selected area electron diffraction, energy-dispersive X-ray spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, thermogravimetric analysis, and BET analysis. The FeNPs were amorphous in nature with average particle size ~ 19 nm and successfully employed as heterogeneous catalyst for the synthesis of quinoxaline, benzimidazole, and pyrazole derivatives in aqueous medium at ambient conditions. The FeNPs could be recycled up to five times with modest change in the catalytic activity. Graphic abstract