A DFT Study on the Mechanism of the Annulation Reaction of Trichloronitroethylene with Aniline in the Synthesis of Quinoxalinone-N-oxides

• Published in: Journal of organic chemistry Vol. 74; no. 13; pp. 4727 - 4739
• Main Authors: Özpınar, Gül A, Erdem, Safiye S, Meyer, Christian, Kaufmann, Dieter E
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 03.07.2009
• Subjects: Chemistry; Exact sciences and technology; Heterocyclic compounds; Heterocyclic compounds with several n hetero atoms in the same ring, in separated rings or in fused rings; Kinetics and mechanisms; Noncondensed benzenic compounds; Organic chemistry; Preparations and properties; Reactivity and mechanisms; Solvent effect; Substituent effect; Quinoxaline derivatives; Four membered ring; Nitrogen heterocycle; Nitrone; Theoretical study; Aniline derivatives; Experimental study; Reaction rate; Annelation; Reaction mechanism; Density functional method; Benzenic compound; Chemical synthesis; Activation energy
• ISSN: 0022-3263; 1520-6904
• DOI: 10.1021/jo9003629

The new annulation reaction of trichloronitroethylene with aniline results in the formation of a quinoxalinone-N-oxide derivative. The mechanism of this one-pot annulation reaction between trichloronitroethylene (TCNiE) and anilines has been extensively investigated with B3LYP/6-31+G** methodology. Five different paths (1−5) were proposed and modeled by using this method. These paths were compared in terms of the activation energies of their rate-determining steps and in regard to the experimental findings. Paths 3 and 5, proceeding via four-membered heterocyclic rings, were found to be the most plausible paths with activation energies of 32 and 29 kcal/mol for the rate-determining steps, respectively. The effects of substituent, solvent, temperature, and computational method on these steps were also investigated. The results showed that path 5 is the most plausible mechanism for the annulation reaction of trichloronitroethylene with aniline.