One-pot synthesis of new benzo[4,5]imidazo[1,2-a]pyrimidines and pyrazolo[1,5-a] pyrimidines as an eco-friendly and effective method catalyzed by acetic acid with prospective antimicrobial agents

A novel set chalcones 3a-d was efficiently synthesized in elevated produces across the condensing process of Claisen-Schmidt. An eco-friendly and efficient process was designed for creating a novel desired products 5a-f and 7a-f, respectively with excellent yields. This synthesis was accomplished by reacting acetophenone derivatives 1a-d, heteroaromatic aldehydes 2a,b and aminobenzoimidazole 4 or 3-aminopyrazole 6a,b, using acetic acid as both the catalyst and solvent. Solvent optimization was performed during the synthesis of the desired compounds 5a or 7a, highlighting the benefits of using acetic acid that is harmless for the environment, which offers easy procedure, rapid reaction, elevated efficiency and broad tolerance of starting materials. The preferred products were verified through compatible spectroscopic data. The antimicrobial efficacious for all compounds was successfully evaluated against various microorganisms, revealing that 3b exhibited significant antimicrobial activity across all tested microbes, with measurements of the minimum inhibitory concentrations being between 4.80 to 63.8 μM.