Redox conversions of new antiviral drug Triazavirin®: electrochemical study and ESR spectroscopy

The results of studying electrochemical conversions of 7-R-3-X-1,2,4-triazolo[5,1-c][1,2,4]-triazin-4-ones (Triazavirin® and its derivatives) using cyclic voltammetry, chronoamperometry, and ESR spectroscopy are presented. The derivatives of 7-R-3-X-1,2,4-triazolo[5,1-c][1,2,4]-triazin-4-ones were found to be capable of electrochemical reducing in the potential range from −0.16 to −0.68 V (vs Ag/AgCl) in a Britton—Robinson buffer at pH 2–12. At the potentials of the first electroreduction step at pH 2–6, the main process of transformations is the four-electron scheme of reduction of the nitro group of Triazavirin®. The adduct of the radical substances with the spin probe N-(1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl)-2-methylpropanamide was registered after the preliminary generation of the Triazavirin® radical anion at −0.5 V vs Ag/AgCl in an acidic medium. A linear dependence of the current of the first electroreduction step of the Triazavirin® on the concentration was obtained at pH 2 (linearity range from 10−4 to 1.6 · 10−2 mol L−1, I = −1.93 · C, R2 = 0.9977).