Ab-initio HF and density functional theory investigations on the synthesis mechanism, conformational stability, molecular structure and UV spectrum of N’-Formylkynurenine

Tryptophan methyl ester (Trp-ME) degrades with singlet oxygen and produce compounds which are photosensitizers and may react to form other derivatives such as N’-Formylkynurenine (NFK) and kynurenine, which are the final products of this oxidation. In order to study and optimize the molecular structure of NFK and determine its different thermodynamic properties, we performed a conformational analysis by DFT/B3LYP method with 3-21G basis set. Six most stable conformations were observed through the analysis of the potential energy surfaces, obtained by a relaxed scan of the dihedral angles. The most stable form of NFK has been registered for D1=−148.96∘, D2=−116.89∘, D3=−39.99∘, D4=−65.50∘, D5=163.75∘, and D6=30.22∘. The study was conducted by HF and DFT/B3LYP with 6-31G(d,p), 6-31+G(d,p) and 6-311+G(d,p) basis sets, on the optimized geometry of the most stable conformation and its thermodynamic and orbital properties. Two absorption bands were recorded at λ=250nm and at λ=340nm and were also determined by ...