Preparation and characterization of kaolin–[TMS]–NH2+C(NO2)3− as a novel heterogeneous nano-catalyst and its use in the synthesis of imidazo[1,2-a]pyrimidine and 1,2,4-triazolo[4,3-a]pyrimidines†

Abstract

This article presents a highly efficient and eco-friendly method for synthesizing imidazo[1,2-a]pyrimidines and 1,2,4-triazolo[4,3-a]pyrimidines using a novel nano-catalyst, kaolin–[TMS]–NH₂⁺C(NO₂)₃⁻, under solvent-free conditions. The catalyst was thoroughly characterized by FT-IR, XRD, TGA, EDX, FESEM, TEM and BET, by combining these techniques, the catalyst's structural integrity, composition, morphology, porosity, and thermal stability were thoroughly validated, making it suitable for high-temperature catalytic applications. The method offers exceptional efficiency, achieving product yields of 92–98% within remarkably short reaction times, significantly outperforming conventional approaches. Notably, the catalyst exhibited excellent recyclability, maintaining its activity over four consecutive cycles without loss of efficiency. Key advantages include simplified product isolation, elimination of hazardous solvents, and a straightforward catalyst synthesis protocol, making this approach both economically and environmentally viable for large-scale applications.