title: Electrochemical and ESR study of 5-nitrofuryl-containing thiosemicarbazones antiprotozoal drugs.
abstract: Cyclic voltammetry and electron spin resonance (ESR) techniques were used in the investigation of several potential antiprotozoal thiosemicarbazones nitrofurane derivatives. A self-protonation process involving the protonation of the nitro group due to the presence of an acidic proton in the thiosemicarbazone moiety was observed in the first step of a CEE(rev) reduction mechanism of these derivatives. ESR spectra of the free radicals obtained by electrolytic reduction were characterized and analyzed. AM1 methodology was used to obtain the optimized geometries and UB3LYP calculations were performed to obtain the theoretical hyperfine coupling constants. The theoretical study exhibited an unusual assignment of the spin densities showing a free radical centered in the thiosemicarbazone moiety rather than the nitro which are in agreement with the experimental hyperfine pattern.
authors.affiliation: Departamento de Química Inorgánica y Analítica, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Olivos 1007 Independencia, Santiago, Chile.
authors.forename: Carolina
authors.initials: C
authors.lastname: Rigol
authors.forename: C
authors.initials: C
authors.lastname: Olea-Azar
authors.forename: Fernando
authors.initials: F
authors.lastname: Mendizábal
authors.forename: Lucía
authors.initials: L
authors.lastname: Otero
authors.forename: Dinorah
authors.initials: D
authors.lastname: Gambino
authors.forename: Mercedes
authors.initials: M
authors.lastname: González
authors.forename: Hugo
authors.initials: H
authors.lastname: Cerecetto
mesh_terms: D000981:Antiprotozoal Agents / Q000737:chemistry*; D004563:Electrochemistry; D004578:Electron Spin Resonance Spectroscopy; D015394:Molecular Structure; D009581:Nitrofurans / Q000737:chemistry*; D009584:Nitrogen / Q000737:chemistry; D010084:Oxidation-Reduction; D013882:Thiosemicarbazones / Q000737:chemistry*
chemical_list: D000981:Antiprotozoal Agents; D009581:Nitrofurans; D013882:Thiosemicarbazones; D009584:Nitrogen