Wolfgang Hutzenlaub

Confirmation of 5-hydroxy-7-methyl-Δ4,9-isouric acid as an intermediate in the electrochemical oxidation of 7-methyluric acid

Abstract 5-Chloro-7-methyl-Δ4,9-isouric acid (11) has been chemically synthesized and shown to be rapidly converted to 5-hydroxy-7-methyl-Δ4,9-isouric acid (14) in aqueous buffers at ca. pH 7. The physical and chemical properties of 14 in solution have been elucidated. Electrochemical oxidation of 7-methyluric acid (10) at its first voltammetric oxidation peak forms a UV-absorbing intermediate. This intermediate exhibits physical and chemical properties which are identical to those of 14. These observations provide the first unequivocal evidence for the chemical structure of a UV-absorbing intermediate formed upon electrochemical oxidation of any purine.