Electrochemistry and Antioxidant Activities of Substituted Furanyl Nitrone: The Role of the Nitro Group

This work compares electrochemical and antioxidant data for synthetic furfural-derived nitrone (LQB-109), the novel N-methyl-nitroaryl-furanyl-nitrone (LQB-569), and the parent aldehyde (5NBFAL). Cyclic voltammograms (CVs) are obtained on a glassy carbon electrode (GCE) in acetonitrile (MeCN) and 0.1 mol L⁻¹ n-Bu₄NPF₆ versus Ag|AgCl|Cl⁻, to evaluate cathodic and anodic behavior and chemical processes. The CVs of LQB-109 display two irreversible cathodic waves at −2.04 V and − 2.19V, related to a four-electron reduction to hydroxylamine. Two anodic waves appeared at +1.32 V and +1.53 V. The first electron uptake for LQB-569 occurs in the nitroaromatic group, followed by reductions to give a more electrophilic nitroso, prone to dimerizing and forming reducible azoxy derivatives, along with nitrone reduction, in a 10-electron total process. One irreversible anodic wave at +1.45 V appears, related to the nitrone oxidation. The electrochemical oxidation profile can be correlated to antioxidant capacity (AO). The ability to scavenge 2,2-diphenil-1-picrylhydrazyl (DPPH)^• radicals (% radical scavenging activity) and reduce ferric complexes (ferric-reducing antioxidant power) were used to assess. LQB-569 showed low AO, due to the presence of the electron-withdrawing group, reflecting the oxidative part of the CVs.