[en] γ-irradiation of thymidine in aerated aqueous solution. I. Identification of the hydroxyhydroperoxides. [fr] Radiolyse gamma de la thymidine en solution aqueuse aérée. I. Identification des hydroxyhydroperoxydes

[en] The primary products formed from the γ-irradiation of thymidine in aerated aqueous solution are nine nucleosidic hydroperoxides. The determination of the configuration of the eight isomers of 6(or 5)-hydroperoxy-5(or 6)-hydroxy-5,6-dihydrothymidine is based on their specific chemical transformation into the corresponding thymidine-5,6-diol. The position of the peroxy group was determined from mass spectrometric measurements of the hydroxy-hydroperoxides obtained from the [18O]-6-exo-halohydrines. 5-hydroperoxymethyl-2-deoxyuridine was identified by a comparison of its spectroscopic and chemical properties with those of the reference compound prepared by the action of hydrogen peroxide on 5-hydromethyl-2'-deoxyuridine in acid media. [fr] La radiolyse γ de la thymidine en solution aqueuse aeree engendre la formation de neuf hydroperoxydes nucleosidiques. La determination de la configuration des huit isomeres de l'hydroperoxy-6 (5) hydroxy-5 (6) dihydro-5,6-thymidine repose sur leur transormation chimique specifique en diols-5,6 correspondants. La position du groupement peroxydique a ete precisee par une etude de spectrometrie de masse des divers hydroperoxydes obtenus par synthese chimique a partir des halohydrines de thymidine 18O6 exo. L'hydroperoxymethyl-5 desoxy-2' uridine a ete identifiee par comparaison des proprietes chimiques et spectroscopiques avec celles du produit temoin prepare par action du peroxyde d'hydrogene sur l'hydroxymethyl-5 desoxy-2' uridine en milieu acide.