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| 001 | 825274 | ||
| 005 | 20210129225252.0 | ||
| 037 | _ | _ | |a FZJ-2016-07745 |
| 041 | _ | _ | |a English |
| 100 | 1 | _ | |a Weiss, Philipp |0 P:(DE-Juel1)145602 |b 0 |
| 111 | 2 | _ | |a 21st International Symposium on Radiopharmaceutical Sciences |g ISRS 2015 |c Columbia |d 2015-05-26 - 2015-05-31 |w USA |
| 245 | _ | _ | |a Synthesis of L-4-[18F]fluorotryptophan starting from isotopic exchange |
| 260 | _ | _ | |c 2015 |
| 336 | 7 | _ | |a Conference Paper |0 33 |2 EndNote |
| 336 | 7 | _ | |a Other |2 DataCite |
| 336 | 7 | _ | |a INPROCEEDINGS |2 BibTeX |
| 336 | 7 | _ | |a conferenceObject |2 DRIVER |
| 336 | 7 | _ | |a LECTURE_SPEECH |2 ORCID |
| 336 | 7 | _ | |a Conference Presentation |b conf |m conf |0 PUB:(DE-HGF)6 |s 1516025113_30484 |2 PUB:(DE-HGF) |x Plenary/Keynote |
| 520 | _ | _ | |a Objectives: Radiofluorinated tryptophan is an interesting tracer candidate. Tryptophan is the precursor of serotonin which is important for a broad variety of neurological regulation processes and is also involved in many neurological diseases, such as depression. Further, it was recently pointed out that some tumors have highly elevated tryptophan consumption to overcome immune barriers [1]. Until now tryptophan has been labelled either in a very complex radiosynthesis by a Schiemann reaction on diethylformamido malonates giving low radiochemical yields (RCY) or by secondary groups [2]. The aim of this work was to find a suitable route for the radiosynthesis of L-4-[18F]fluorotryptophan, starting from isotopic exchange. Tests with bacteria showed no toxicity of the title compound [4].Methods: Starting from 4-fluoroindole, the precursor for the radiosynthesis of 4-fluorotryptophan was prepared in a linear 11 step synthesis with an overall yield of 8 %, following a modified route to the one described by Konas et al. [3]. The radiosynthesis was designed and carried out in three steps: isotopic exchange, reductive decarbonylation and hydrolysis of protecting groups. All reactions were optimized regarding time, solvents, temperature and concentration of reagents. Results: It was found that the optimum temperature for the radiofluorination is 80 °C, yielding a RCY of 51 %. Above 90 °C almost complete decomposition of the starting material occurred. For the reductive decarbonylation the best results were obtained using benzonitrile as solvent and 3 equivalents of Wilkinson’s catalyst. The reaction was performed under either conventional or microwave heating giving RCYs of about 78 %. The final hydrolysis gave yields of about 34 %. Conclusion: The whole radiosynthesis of L-4-[18F]fluorotryptophan was achieved in about 115 min with an overall RCY of ca. 13 %, a molar activity of > 70 MBq/mmol and an enantiomeric purity of > 99 %. This new radiotracer is now available for preclinical evaluation studies.References: [1] Prendergast G.C., (2011) Nature, 478, 192-194. [2] Ermert J., (2013) J. Labelled Compds Radiopharm., 56, 225-236. [3] Konas D.W. et al., (2012) Synth. Comm., 42, 144-152. [4] Bacher J.M., (2001) J. Bacteriol., 183, 5414-5425. |
| 536 | _ | _ | |a 572 - (Dys-)function and Plasticity (POF3-572) |0 G:(DE-HGF)POF3-572 |c POF3-572 |f POF III |x 0 |
| 700 | 1 | _ | |a Castillo, Johnny |0 P:(DE-Juel1)131815 |b 1 |
| 700 | 1 | _ | |a Ermert, Johannes |0 P:(DE-Juel1)131818 |b 2 |e Corresponding author |u fzj |
| 700 | 1 | _ | |a Coenen, Heinrich Hubert |0 P:(DE-Juel1)131816 |b 3 |u fzj |
| 909 | C | O | |o oai:juser.fz-juelich.de:825274 |p VDB |
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| 913 | 1 | _ | |a DE-HGF |b Key Technologies |l Decoding the Human Brain |1 G:(DE-HGF)POF3-570 |0 G:(DE-HGF)POF3-572 |2 G:(DE-HGF)POF3-500 |v (Dys-)function and Plasticity |x 0 |4 G:(DE-HGF)POF |3 G:(DE-HGF)POF3 |
| 920 | _ | _ | |l yes |
| 920 | 1 | _ | |0 I:(DE-Juel1)INM-5-20090406 |k INM-5 |l Nuklearchemie |x 0 |
| 980 | _ | _ | |a conf |
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| 980 | _ | _ | |a UNRESTRICTED |
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