Polarographic analysis of heterocyclic nitrogen compounds

Abstract

A correlation between the reduction potential of heterocyclic compounds and their effectiveness as radiosensitizing agents in cancer therapy has been reported in the literature. This correlation provides a guide for evaluating the effectiveness of newly synthesized compounds as radiosensitizers. The half-wave reduction potential ( E 1/2) of selected nitroimidazoles, nitrotriazoles and heterocyclic amine N-oxides was measured at a dropping mercury electrode in a Britton-Robinson buffer, pH 7.4. The effect of various substituent groups on the half-wave reduction potential of the heterocyclic compounds was investigated and the results are compared with published data. A single reduction wave was observed with the nitroimidiazoles and nitrotriazoles, whereas multiple reduction waves were conserved with several of the N-oxides of pyridine, quinoxaline and phenazine. When electron-attracting substituents were attached to the heterocyclic ring on nitroimidazole and nitrotriazole, the reduction of the nitro group was easier and E 1/2 shifted in the positive direction relative to that of the parent compound.