New pyrimidoquinoxaline nitrones as spin traps

ROBERTO CIPOLLETTI; PIERLUIGI STIPA; NADIA GRUBER; LILIANA R. ORELLI

Marseille

Conferencia; IXth EF-EPR Conference; 2014

European Federation of EPR

Electron Paramagnetic Resonance (EPR)-Spin Trapping is one of the most reliable techniques for detecting and identifying short-lived free radicals. It is based upon the fast reaction between a suitable diamagnetic molecule (a spin trap) and a transient free radical with formation of a relatively long-lived adduct, whose parameters (h.f.c.cs., and g-factor) are characteristic of the type of the initial radical. [1] Nitrones (N-oxides) represent the most commonly used spin traps [2] and they are continuously object of studies aimed at improving their efficiency and the stability of the corresponding spin adducts. A series of 2,3-Dihydro- 1H-pyrimido[1,2-a]quinoxaline-6-Oxides (1-4) was prepared and tested as spin traps by EPR spectroscopy. Although less reactive with respect to the previously synthesized benzoxazine analogues [2] for the steric hindrance at nitrone alpha-carbon, all derivatives tested were able to efficiently scavenge the radicals used in this study.