Oxidation chemistry of 1,3-dimethylxanthine at stationary pyrolytic graphite electrode

Article abstract of DOI:10.1246/bcsj.71.199

The electrochemical oxidation of 1,3-dimethylxanthine has been studied in the pH range 2.3 - 10.3 at a pyrolytic graphite electrode. The conjugate base has been found as the electroactive species oxidized over the entire pH range. The 4e, 4H⁺ charge transfer step is followed by competitive irreversible chemical reactions. The decomposition of UV-absorbing intermediate generated during the electrooxidation has been found to follow first-order kinetics. The products of the EC reaction have been separated by HPLC and gel-permeation chromatography and characterized by mp, ¹HNMR, and mass spectra. The presence of methyl groups of positions 1 and 3 has been found to affect the course of mechanism, because the positive charge developed on nitrogen does not permit ring contraction. A tentative mechanism has also been suggested.