Unexpected Behavior of the Heaviest Halogen Astatine in the Nucleophilic Substitution of Aryliodonium Salts

Abstract : Aryliodonium salts have become precursors of choice for the synthesis of 18 F-labeled tracers for nuclear imaging. However, little is known on the reactivity of these compounds with heavy halides, that is, radioiodide and asta-tide, at the radiotracer scale. In the first comparative study of radiohalogenation of aryliodonium salts with 125 I À and 211 At À , initial experiments on a model compound highlight the higher reactivity of astatide compared to iodide, which could not be anticipated from the trends previously observed within the halogen series. Kinetic studies indicate a significant difference in activation energy (E a = 23.5 and 17.1 kcal mol À1 with 125 I À and 211 At À , respectively). Quantum chemical calculations suggest that astatination occurs via the monomeric form of an iodonium complex whereas iodi-nation occurs via a heterodimeric iodonium intermediate. The good to excellent regioselectivity of halogenation and high yields achieved with diversely substituted aryliodonium salts indicate that this class of compounds is a promising alternative to the stannane chemistry currently used for heavy radiohalogen labeling of tracers in nuclear medicine.
Type de document :
Article dans une revue
Chemistry - A European Journal, Wiley-VCH Verlag, 2016, 〈10.1002/chem.201600922〉
Liste complète des métadonnées

Littérature citée [30 références]  Voir  Masquer  Télécharger

http://www.hal.inserm.fr/inserm-01387016
Contributeur : Elizabeth Bernardo <>
Soumis le : mardi 25 octobre 2016 - 09:14:48
Dernière modification le : jeudi 15 mars 2018 - 14:10:54

Fichier

 Accès restreint
Fichier visible le : jamais

Connectez-vous pour demander l'accès au fichier

Identifiants

Collections

Citation

François Guérard, Yong-Sok Lee, Kwamena Baidoo, Jean-François Gestin, Martin Brechbiel. Unexpected Behavior of the Heaviest Halogen Astatine in the Nucleophilic Substitution of Aryliodonium Salts. Chemistry - A European Journal, Wiley-VCH Verlag, 2016, 〈10.1002/chem.201600922〉. 〈inserm-01387016〉

Partager

Métriques

Consultations de la notice

80