A cyclic voltammetric study of some quinoxaline di-n-oxides and quinoxalines in acetonitrile: substituent effect on the cathodic reduction

Cyclic Voltammetric Study of Some Anti‐Chagas‐Active 1,4‐Dioxidoquinoxalin‐2‐yl Ketone Derivatives

“…chloro, fluoro, difluoromethyl, and trifluoromethyl) or an electron-releasing group (i.e. methyl and methoxy) onto the conjugated quinoxaline ring have been reported in previous studies [7,12,13,14,16,17,18]. The present study correlates well with these earlier reports on the structural effects on potential.…”

“…In fact, reduction of quinoxaline 1,4-di-N-oxide in DMF has been shown via ESR and electrochemistry to involve one-electron reduction of the nitrone to the radical anion [15]. A second, irreversible voltammetric wave was observed for all derivatives at potentials between -1.7 and -2.4 V (Tables 2 and 3, Figures 1c and 2c), and is attributed to formation of the dianion [17]. The irreversibility of this voltammetric wave might be due to a following chemical reaction, i.e.…”

Novel quinoxaline 1,4-di-N-oxide derivatives as new potential antichagasic agents

“…For example, replacing the 7-hydrogen atom in compound 10 with the 7-methyl group in derivative 12 and the 7-methoxy group in 11 resulted in shifts in E 1/2 of -0.043 V and -0.076 V, respectively. The results of the present study agree with previous electrochemical studies dealing with the effects of structure on the reduction potentials of quinoxaline di-N-oxide derivatives, [46][47][48][50][51][52] and indicate that reduction is facilitated by a positive charge at the reaction site. [53] The influence of the substituent at R 2 , i.e.…”

“…[44,45] The electrochemical reductions of various quinoxaline di-N-oxide derivatives in aprotic solvent systems have been reported previously. [46][47][48][49][50][51][52]. In the current study, several voltammetric waves were observed during cyclic voltammetry of the quinoxaline di-N-oxide derivatives between -0.4 and -2.3 V. The first reduction process observed in the voltammograms may be attributed to reduction of the nitrone functionality, forming a radical anion (Figure 1).…”

“…In the current study, several voltammetric waves were observed during cyclic voltammetry of the quinoxaline di-N-oxide derivatives between -0.4 and -2.3 V. The first reduction process observed in the voltammograms may be attributed to reduction of the nitrone functionality, forming a radical anion (Figure 1). [46][47][48][49][50][51][52] …”