Reaction of [18F]4-fluorobenzenediazonium cations with cysteine or the cysteinyl group: preparation of 18F-labeled S-aryl-cysteine and a radiolabeled peptide
✍ Scribed by J. T. Patt; M. Patt
- Publisher
- John Wiley and Sons
- Year
- 2002
- Tongue
- French
- Weight
- 109 KB
- Volume
- 45
- Category
- Article
- ISSN
- 0022-2135
- DOI
- 10.1002/jlcr.635
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✦ Synopsis
Abstract
A reaction route for the preparation of no‐carrier‐added (n.c.a.) [^18^F]S‐4‐fluorophenylcysteine 7 via the [^18^F]‐4‐fluorobenzenediazonium ion 4 is described. The key step in this radiosynthesis is the reaction of 4 with cysteine forming [^18^F]4‐fluorophenyldiazocysteine 6, which is subsequently converted into 7 by irradiation with 366 nm light. 4 was synthesized by reacting 1,4‐dinitrobenzene 1 with [^18^F]‐fluoride in acetonitrile in a PEEK‐capillary in a microwave oven. After dilution of the reaction mixture with methanol, the resulting [^18^F]4‐fluoro‐1‐nitrobenzene 2 was submitted to reduction by means of H~2~ with Pd on C catalyst. The resulting [^18^F]4‐fluoroaniline 3 was purified by HPLC and diazotized to 4. The preparation of 4 was optimized with regard to yield and purity. The radiochemical yield of 6 was >90% (based on 3) while after UV irradiation and HPLC purification 45% of 7 (based on 3) was obtained (yields corrected for decay). The suitability of this method for labeling peptides with fluorine‐18 was demonstrated by application to the tripeptide, glutathione (GSH; γ‐L‐glutamyl‐L‐cysteinyglycine) 8. Copyright © 2002 John Wiley & Sons, Ltd.