Electrochemical Behavior of Quinoxalin-2-one Derivatives at Mercury Electrodes and Its Analytical Use

0376610 - ÚFCH JH 2013 RIV US eng J - Journal Article
Zimpl, M. - Skopalová, J. - Jirovský, D. - Barták, P. - Navrátil, Tomáš - Sedoníková, J. - Kotouček, M.
Electrochemical Behavior of Quinoxalin-2-one Derivatives at Mercury Electrodes and Its Analytical Use.
Scientific World Journal. Roč. 2012, č. 2012 (2012), s. 409378. ISSN 1537-744X
R&D Projects: GA AV ČR IAA400400806
Institutional research plan: CEZ:AV0Z40400503
Keywords : electrochemistry * quinoxalin-2-one * electrodes
Subject RIV: CG - Electrochemistry
Impact factor: 1.730, year: 2012
http://www.tswj.com/2012/409378/

Derivatives of quinoxalin-2-one are interesting compounds with potential pharmacological activity. From this point of view, understanding of their electrochemical behavior is of great importance. In the present paper, a mechanism of electrochemical reduction of quinoxalin-2-one derivatives at mercury dropping electrode was proposed. Pyrazine ring was found to be the main electroactive center undergoing a pH-dependent two-electron reduction process. The molecule protonization of nitrogen in the position 4 precedes the electron acceptance forming a semiquinone radical intermediate which is relatively stable in acidic solutions. Its further reduction is manifested by separated current signal. A positive mesomeric effect of the nonprotonized amino group in the position 7 of the derivative III accelerates the semiquinone reduction yielding a single current wave. The suggested reaction mechanism was verified by means of direct current polarography, differential pulse, cyclic and elimination voltammetry, and coulometry with subsequent GC/MS analysis. The understanding of the mechanism was applied in developing of analytical method for the determination of the studied compounds.
Permanent Link: http://hdl.handle.net/11104/0208967