Formation of free radicals during the oxidation of N-methylhydroxyurea with dioxovanadium(V) ions

Unlike the oxidation of hydroxyurea with dioxovanadium(V) ions, which proceeds through the formation of a single free radical, oxidation of N-methylhydroxyurea is characterized by consecutive formation of two oxygen-based free radicals, as recorded by EPR spectroscopy. Although the consumption of overall five V(V) ions per N-methylhydroxyurea molecule has been determined, the formation of NO, NO 2 - or NO 3 - was not observed. These results are in accordance with a previous suggestion that nitric oxide transfer requires an unsubstituted acylhydroxylamine group.