Radical trapping properties of imidazolyl nitrones

Karine Reybier (1) , Jeremie Boyer (1) , Vincent Farines (1) , Fabrice Camus (2) , Jean-Pierre Souchard (1) , Marie-Carmen Monje (1) , Vania Bernardes-Génisson (1) , Solo Goldstein (3) , Françoise Nepveu (1)

1 PHARMA-DEV - Pharmacochimie et Biologie pour le Développement
2 FUNDP - Facultés Universitaires Notre Dame de la Paix
3 IRIS - Institut de Recherches Internationales Servier [Suresnes]

The ability of ten imidazolyl nitrones to directly scavenge free radicals (R√) generated in polar (√OH, cysteinyl, √CH3) or in apolar (CH3–√CH–CH3) media has been studied. When oxygen or sulfur-centered radicals are generated in polar media, EPR spectra are not or weakly observed with simple spectral features. Strong line intensities and more complicated spectra are observed with the isopropyl radical generated in an apolar medium. Intermediate results are obtained with √CH3 generated in a polar medium. EPR demonstrates the ability of these nitrones to trap radicals to the nitrone C(α) atom (alpha radical adduct) and to the imidazol C(5) atom (5-radical adduct). Beside the nucleophilic addition of the radical to the C(α) atom, the EPR studies suggest a two-step mechanism for the overall reaction of R√ attacking the imidazol core. The two steps seem to occur very fast with the √OH radical obtained in a polar medium and slower with the isopropyl radical prepared in benzene. In conclusion, imidazolyl nitrones present a high capacity to trap and stabilize carbon-centered radicals.

Mots clés: Imidazolyl nitrones; Carbon- and hetero-centered radicals; Spin traps; EPR

Domaines: Génie chimique; Génie des procédés

Karine Reybier, Jeremie Boyer, Vincent Farines, Fabrice Camus, Jean-Pierre Souchard, et al.. Radical trapping properties of imidazolyl nitrones. Free Radical Research, 2006, 40 (1), pp.11-20. ⟨10.1080/10715760500329598⟩. ⟨hal-02143180⟩