How to increase the reactivity of [18F]fluoroethyl bromide: [18F]fluoroethylation of amine, phenol and amide functional groups with [18F]FEtBr, [18F]FEtBr/NaI and [18F]FEtOTf
✍ Scribed by Ming-Rong Zhang; Kenji Furutsuka; Yuichiro Yoshida; Kazutoshi Suzuki
- Publisher
- John Wiley and Sons
- Year
- 2003
- Tongue
- French
- Weight
- 124 KB
- Volume
- 46
- Category
- Article
- ISSN
- 0022-2135
- DOI
- 10.1002/jlcr.703
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✦ Synopsis
Abstract
[^18^F]Fluoroethyl bromide ([^18^F]FEtBr) is a useful synthetic precursor to synthesize ^18^F‐labeled compounds. However, the lower reactivity of [^18^F]FEtBr with amine, phenol and amide functional groups than that of [^11^C]CH~3~I partly limits its wide application in the synthesis of [^18^F]fluoroethylated compounds. The aim of this study was to increase the reactivity of [^18^F]FEtBr with various nucleophilic substrates for PET tracers containing amine, phenol and amide moieties. The present strategies included (1) adding NaI into the reaction mixture of [^18^F]FEtBr and substrate, where [^18^F]FEtI is reversibly formed and becomes more reactive; (2) converting [^18^F]FEtBr into much more reactive [^18^F]FEtOTf, similar to conversion of [^11^C]CH~3~I into [^11^C]CH~3~OTf. By these efforts, the [^18^F]fluoroethylation efficiency of various substrates containing amine, phenol and amide groups with [^18^F]FEtBr/NaI and [^18^F]FEtOTf was significantly improved, compared with the corresponding reaction efficiency with [^18^F]FEtBr. Copyright © 2003 John Wiley & Sons, Ltd.