Green Synthesis of Dihydropyrimidine Annulated Heterocyclic Systems Catalyzed by Nanoporous Na⁺-Montmorillonite Perchloric Acid and Evaluation of Their Biological Activities

Abstract

An efficient and environmentally benign method for the green one-pot synthesis of dihydrobenzoimidazolo pyrimidine derivatives has been developed by multi-component reaction of 2-aminobenzimidazole, ethyl acetoacetate or malononitrile and aromatic aldehydes using nanoporous Na⁺-montmorillonite perchloric acid as a novel heterogeneous solid acid catalyst. The catalyst was easily prepared and characterized by X-ray powder diffraction, FTIR, SEM-EDX, TGA, BET, nitrogen adsorption–desorption measurements, pH analysis, and Hammett acidity function. Also, the antibacterial activity of synthesized compounds was evaluated and some products showed good activity. Availability and low cost of the reagent, ease of preparation and reusability of the catalyst, short reaction times, high yields of the products, operational simplicity, and solvent-free reaction conditions are some of the main advantages of this novel synthetic method.

Keywords:

• 2-Amino benzimidazole
• ethyl acetoacetate
• malononitrile
• multi-component reactions
• nano clay

Additional information

Funding

We are thankful to the University of Guilan Research Council for the partial support of this work.