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| Hauptseite > Publikationsdatenbank > Zur Synthese radiofluorierter aromatischer Aminosäuren mittels Isotopenaustausch am Beispiel von 6-[$^{18}$F]Fluor-L-DOPA > print |
| Hauptseite > Publikationsdatenbank > Zur Synthese radiofluorierter aromatischer Aminosäuren mittels Isotopenaustausch am Beispiel von 6-[$^{18}$F]Fluor-L-DOPA > print |
| 001 | 62451 | ||
| 005 | 20200610183931.0 | ||
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| 088 | 1 | _ | |a Juel-4273 |
| 088 | _ | _ | |a Juel-4273 |2 JUEL |
| 100 | 1 | _ | |0 P:(DE-Juel1)VDB76321 |a Wagner, Franziska M. |b 0 |e Corresponding author |u FZJ |
| 245 | _ | _ | |a Zur Synthese radiofluorierter aromatischer Aminosäuren mittels Isotopenaustausch am Beispiel von 6-[$^{18}$F]Fluor-L-DOPA |
| 260 | _ | _ | |a Jülich |b Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag |c 2008 |
| 300 | _ | _ | |a III, 188 p. |
| 336 | 7 | _ | |0 PUB:(DE-HGF)11 |2 PUB:(DE-HGF) |a Dissertation / PhD Thesis |
| 336 | 7 | _ | |0 PUB:(DE-HGF)3 |2 PUB:(DE-HGF) |a Book |
| 336 | 7 | _ | |0 2 |2 EndNote |a Thesis |
| 336 | 7 | _ | |2 DRIVER |a doctoralThesis |
| 336 | 7 | _ | |2 BibTeX |a PHDTHESIS |
| 336 | 7 | _ | |2 DataCite |a Output Types/Dissertation |
| 336 | 7 | _ | |2 ORCID |a DISSERTATION |
| 490 | 0 | _ | |0 PERI:(DE-600)2414853-2 |8 31012 |a Berichte des Forschungszentrums Jülich |v 4273 |x 0944-2952 |
| 500 | _ | _ | |a Record converted from VDB: 12.11.2012 |
| 502 | _ | _ | |a Köln, Univ., Diss., 2008 |b Dr. (Univ.) |c Univ. Köln |d 2008 |
| 520 | _ | _ | |a In nuclear medical diagnosis, 6-[$^{18}$F]fluoro-L-3,4-dihydroxyphenylalanine (6-[$^{18}$F]fluoro-LDOPA), an analogue of L-DOPA, is one of the few established radiopharmaceuticals used for the in vivo investigation of the presynaptic dopaminergic metabolism and of some kind of tumours via Positron Emission Tomography (PET). The presently used method of preparation of the radiotracer by electrophilic labelling is limited to low amounts of activity at high costs. Known nucleophilic syntheses, however, result either in insufficient enantiomeric purity or the known multi-step syntheses are hard to automate, due to their complexity. During this work a novel, easy to automate alternative for the preparation of 6-[$^{18}$F]fluoro-L-DOPA, was developed and evaluated, using a direct nucleophilic $^{18}$F-fluorination of a protected amino acid derivative. The resulting product has a very high enantiomeric purity. At first, the general suitability of the (S)-BOC-BMI-derivatives for the synthesis of $^{18}$F-labelled amino acids, used in this work, was investigated using a less complex precursor, which resulted in the amino acid 6-[$^{18}$F]fluoro-L-m-tyrosin via acidic hydrolysis. The preparation of a useful precursor for the nucleophilic $^{18}$F-isotope substitution, namely the (2S,5S)-tert.-butyl-5-(2-fluoro-5-formylbenzyl)-2-tert.-butyl-3-methyl-4-oxoimidazolidine-1-carboxylate, was investigated in three general different ways. At first it was tried to obtain this product via formylation after coupling with the BOC-BMI, secondly via a,b-dehydro amino acid derivatives and finally via a systematic multi-step synthesis. Only the last mentioned way resulted in a precursor with sufficient purity that could be labelled. The radiochemical yield of the isotopic exchange was about 60 %. In the next step, the presented concept was modified to synthesize a precursor for the preparation of 6-[$^{18}$F]fluoro-L-DOPA. Only a combination of the protecting groups benzyl and THP resulted in the useful precursor (2S,5S)-tert.-butyl-5-(4-benzyloxy-2-fluoro-5-formylbenzyl)-2-tert.-butyl-3-methyl-4-oxoimidazolidine-1-carboxylate. By optimisation of the isotopic exchange with [18F]fluoride on this precursor a radiochemical yield of about 50 % was achieved. After a three step synthesis including the labelling, a Baeyer-Villiger-oxidation using mCPBA and a hydrolysis using HBr, c.a. 6-[$^{18}$F]fluoro-L-DOPA was isolated containing more than 99 % of the desired L-isomer. The complete preparation and isolation of c.a. 6-[$^{18}$F]fluoro-L-DOPA, using optimised conditions, resulted in a decay corrected yield of about 22 % after a synthesis time of 105 minutes. Thus the presented synthesis of 6-[$^{18}$F]fluoro-L-DOPA is not only more efficient than the known methods of preparation, but is furthermore fully automatable. |
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