Characterization, Synthesis, and Antimicrobial Activities of Quinazoline Derivatives [EMNEDAQZHO]and their Metal Ion Complexes

The synthesis, characterization, and antimicrobial evaluation of quinazoline derivatives and their metal ion complexes have garnered significant attention in medicinal chemistry due to their potential therapeutic applications. This study reports the preparation of novel quinazoline derivatives through a deaminative coupling reaction between substituted acetonaphthone and 2-methyl-4H-1,3-benzoxazine-4-one using different amines. Additionally, the coordination behavior of these quinazoline derivatives with metal ions such as Co²⁺, Ni²⁺, Cu²⁺, and Zn²⁺ was explored, resulting in stable metal-ligand complexes. The structural and physico-chemical properties of the synthesized ligand [EMNEDAQZHO] and its metal complexes were analyzed using a combination of volumetric techniques and advanced characterization methods, including FTIR, ¹H NMR, UV-Vis, TGA, and mass spectrometry. Thermogravimetric analysis (TGA) was employed to assess thermal stability, metal content, and moisture loss in the complexes. The antimicrobial activities of the quinazoline Schiff base ligand [EMNEDAQZHO] and its metal complexes were evaluated against a range of bacterial and fungal strains, with minimum inhibitory concentrations (MIC) determined at varying concentrations. This study successfully demonstrates the synthesis of quinazoline derivatives [AMQZHO] and Schiff base [EMNEDAQZHO], as well as their metal ion complexes, through both established and novel synthetic methodologies. The antimicrobial assays revealed that coordination with metal ions significantly enhances the biological activity of the ligands, making these complexes promising candidates for the development of new antimicrobial agents in pharmaceutical applications.