Synthesis, antioxidant effect and theoretical calculation studies of syringaldehyde based 2,4,6-triarypyridines

ABSTRACT SYNTHESIS, ANTIOXIDANT EFFECT AND THEORETICAL CALCULATION STUDIES OF SYRINGALDEHYDE BASED 2,4,6-TRIARYPYRIDINES Esra Nur ALBAYRAK Düzce University Graduate School of Natural and Applied Sciences, Department of Chemistry Master's Thesis Supervisor: Assoc. Prof. Dr. Alparslan ATAHAN July 2023, 78 pages In this thesis, eight new 2,4,6-triarylpyridine derivative compounds derived from syringaldehyde were designed and these structures were successfully synthesized by using one-step multi-component method. For this, syringaldehyde compound was reacted with different methyl ketone derivatives in the presence of ammonium acetate under reflux and in DMF. The structure of each obtained pyridine derivative was elucidated using 1H-NMR, 13C-NMR and FTIR techniques. The antioxidant activities of these compounds, whose their structures were elucidated, were determined according to the methods commonly used in the literature and by comparing them with known reference compounds. Then, computer aided theoretical quantum calculations of the obtained structures were carried out. These calculations have been extensively completed in the water and gas phases using B3LYP theory and the SVP and TZVP basis sets. In addition, in these calculations, theoretical parameters such as hardness, softness, HOMO-LUMO energy levels, which are extremely important molecular descriptors for understanding the electronic nature and bioactivity results of the proposed structures, were revealed. Then, electronic structure descriptive parameters called Fukui indices, which is one of the most important descriptors for this study and defines the radical capture potential, were determined. Finally, the structure-activity relationship for the compounds within the scope of the thesis study was revealed by evaluating the theoretically calculated and experimentally obtained results together. As a result, the compounds in this study were evaluated within the framework of structure-activity relationship, and the potential of using the whole series as antioxidant agents was revealed. Keywords: Syringaldehyde, Pyridine, Antioxidant, DFT, Fukui indices