title: Formation of aminoxyl radicals in the reaction between penicillins and hydrogen peroxide.
abstract: Aminoxyl radicals are formed in high yield in the reaction between penicillins and hydrogen peroxide in water solutions in the pH range between 7 and 8. The nine-line EPR spectrum, 3 x 3 (1:2:1), indicated an interaction of the unpaired electron with one 14N nucleus (aN = 1.44 mT) and two equivalent hydrogen nuclei (aH = 2.00 mT). The reaction involves an oxidative cleavage of the beta-lactam ring of the penicillins with the formation of a cyclic aminoxyl radical, in which the thiazolidine ring carries the nitroxide group (= N-O.). It is suggested that the reaction with the formation of aminoxyl radicals can also take place in vivo in the deactivation of penicillins by metabolically formed hydrogen peroxide.
authors.affiliation: Department of Medical Physics, University of Göteborg, Sweden.
authors.forename: C
authors.initials: C
authors.lastname: Lagercrantz
mesh_terms: D004578:Electron Spin Resonance Spectroscopy; D005609:Free Radicals / Q000737:chemistry; D006861:Hydrogen Peroxide / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D010084:Oxidation-Reduction; D010406:Penicillins / Q000737:chemistry*; D012996:Solutions
chemical_list: D005609:Free Radicals; D010406:Penicillins; D012996:Solutions; D006861:Hydrogen Peroxide