Synthesis of amino acid-based multifunctional heterocyclic compounds and investigation of fe(III), CT(III) metal complexes

In our study focuses on the synthesis of benzimidazoles and benzoxazoles, which represent a class of electron-rich heterocyclic compounds known for their versatile chemical properties and broad utility. During the synthesis phase, 1,2-phenylenediamine and 2-aminophenol were reacted with various proteinogenic amino acids, including L-glycine, L-alanine, L-methionine, L-tyrosine, L-glutamine, L-serine, L-glutamic acid, and L-phenylalanine. A total of 16 distinct ligands were successfully derived from these amino acid-based precursors. The significance of these heterocyclic structures lies in their role as essential pharmacophores in the development of numerous therapeutic agents, which constitutes the primary rationale for their selection in this research. In the second stage of the study, 1,3,5-tribromobenzene was employed as a central building block to react with the 16 synthesized ligands, yielding 24 different versatile heterocyclic derivatives. The third stage involved the coordination of these heterocyclic compounds to [{Fe(salen)}₂O] and [{Cr(salen)}₂O] complexes—synthesized in accordance with established literature procedures. This coordination occurred via the –COOH groups of the ligands, resulting in the formation of double oxygen-bridged structures. The chemical structures of the resulting ligands and heterocyclic compounds were rigorously characterized using FT-IR, ¹H-NMR, and elemental analysis. Furthermore, the structural elucidation of the homonuclear complexes was supported by magnetic susceptibility measurements and elemental analysis data.