New Amidinoquinoxaline Nitrones as Antioxidants 

NADIA GRUBER; LILIANA R. ORELLI; ROBERTO CIPOLLETTI; PIERLUIGI STIPA; SIMONA SABBATINI; GIOVANNA MOBBILI; CRISTINA MINNELLI

Torino

Conferencia; Xth Conference of the European Federation of EPR groups; 2016

Italian EPR group (GIRSE)

New Amidinoquinoxaline Nitrones as AntioxidantsNadia Gruber1, Liliana R. Orelli1, Roberto Cipolletti2, Pierluigi Stipa2,Simona Sabbatini2, Giovanna Mobbili3, Cristina Minnelli31) Dpto. de Química Orgánica, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, CONICET. Junín 956, Buenos Aires, Argentina.2) SIMAU Dept. ? Chemistry Division, Università Politecnica delle Marche, Via Brecce Bianche 12, Ancona (I-60131) Italy.3) DISVA Dept., Università Politecnica delle Marche, Via Brecce Bianche 12, Ancona (I-60131) Italy.Electron Paramagnetic Resonance (EPR)-Spin Trapping is one of the most reliable techniques for detecting and identifying short-lived free radicals.1 Nitrones (N-oxides) represent the most commonly used spin traps2 and they are continu-ously object of studies aimed at improving their efficiency and the stability of the corresponding spin adducts. A series of amidinoquinoxaline N-oxides was prepared and tested as spin traps by EPR spectroscopy3,5. Although less reactive with respect to the previously synthesized benzoxazine analogues4 due to steric hindrance at nitrone alpha-carbon, all derivatives tested were able to efficiently scavenge the carbon- and oxygen-centered radicals used in this study. Additionally, very persistent HOO radical adducts have been found, likely due to their different possibilities to yield intramolecular H-bonds, as showed by proper DFT studies. Taking into account these features, the nitrones have been successfully studied as antimicrobials5 and, more recently as antioxidants in biological systems, showing also in this last case a promising behavior. In particular, the antioxidant activity of these compounds was assessed in the AAPH induced oxidation of phosphatidylcholine liposomes by measuring the TBARS production.References.1.E. G. Janzen, B. J. Blackburn, J. Am. Chem. Soc. 1968, 90, 5909.2.E. G. Janzen, Acc. Chem. Res.1971, 4, 31.3.N. Gruber, L. L. Piehl, E. Rubin de Celis, J. E. Díaz, M. B. García, P. Stipa, L. R. Orelli, RSC Advances, 2015, 5, 2724.4.P. Stipa, P. Astolfi, M. Marini, J. Org. Chem., 2007, 72, 8677.5.N. Gruber, PhD Thesis, Universidad de Buenos Aires, Argentina, 2016.