Enzymatic synthesis of no-carrier-added 6-[18F]fluoro-l-dopa with β-tyrosinase

Kaneko, Shoji; Ishiwata, Kiichi; Hatano, Kentaro; Omura, Hironori; Ito, Kengo; Senda, Michio

doi:10.1016/s0969-8043(98)00173-0

Cited by 25 publications

(12 citation statements)

References 17 publications

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“…It has been reported that 18 F-labeled catechol can potentially be converted to 18 F-DOPA (Kaneko et al, 1999). However, synthesis of 18 F-catechol via electrochemical fluorination of catechol is challenging.…”

Section: Resultsmentioning

confidence: 99%

“…Di- tert -butyl-(4-( tert -butyl)-1,2-phenylene)-dicarbonate 6 was synthesized and electrochemical radiofluorination of the above precursor was conducted on a specifically developed automated electrochemistry platform. This compound is a relevant model to an important class of PET radiopharmaceuticals and can potentially be converted to [ 18 F]DOPA (Kaneko et al, 1999). The products were detected and identified with mass spectrometry (MS), high-performance liquid chromatography (HPLC) and thin layer chromatography (TLC).…”

Section: Introductionmentioning

confidence: 99%

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Electrochemical nucleophilic synthesis of di-tert-butyl-(4-[18F]fluoro-1,2-phenylene)-dicarbonate

Wang

Alfeazi

et al. 2014

Applied Radiation and Isotopes

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An electrochemical method with the ability to conduct 18F-fluorination of aromatic molecules through direct nucleophilic fluorination of cationic intermediates is presented in this paper. The reaction was performed on a remote-controlled automatic platform. Nucleophilic electrochemical fluorination of tert-butyloxycarbonyl (Boc) protected catechol, an intermediate model molecule for the positron emission tomography (PET) probe (3,4-dihydroxy-6-[18F]fluoro-l-phenylalanine), was performed. Fluorination was achieved under potentiostatic anodic oxidation in acetonitrile containing Et3N · 3HF and other supporting electrolytes. Radiofluorination efficiency was influenced by a number of variables, including the concentration of the precursor, concentration of Et3N · 3HF, type of supporting electrolyte, temperature and time, as well as applied potentials. Radiofluorination efficiency of 10.4 ± 0.6% (n = 4) and specific activity of up to 43 GBq/mmol was obtained after 1 h electrolysis of 0.1 M of 4-tert-butyl-diboc-catechol in the acetonitrile solution of Et3N · 3HF (0.033 M) and NBu4PF6 (0.05 M). Density functional theory (DFT) was employed to explain the tert-butyl functional group facilitation of electrochemical oxidation and subsequent fluorination.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Electrochemical nucleophilic synthesis of di-tert-butyl-(4-[18F]fluoro-1,2-phenylene)-dicarbonate

Wang

Alfeazi

et al. 2014

Applied Radiation and Isotopes

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“…Thus, the synthesis had to be further improved to comply with this limit. A promising approach was presented by Kaneko et al in 1999 (Figure 7) [77]. The enzymatic reaction step was evaluated carefully and provided a conversion rate of 58% from [ 18 F]fluorocatechol ([ 18 F ] 21 ) to [ 18 F]F-DOPA ([ 18 F ] 7 ) under optimized conditions.…”

Section: Nucleophilic Synthesis Strategies For the Production Of [mentioning

confidence: 99%

6-[¹⁸F]Fluoro-L-DOPA: A Well-Established Neurotracer with Expanding Application Spectrum and Strongly Improved Radiosyntheses

Pretze

Wängler

2014

BioMed Research International

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For many years, the main application of [18F]F-DOPA has been the PET imaging of neuropsychiatric diseases, movement disorders, and brain malignancies. Recent findings however point to very favorable results of this tracer for the imaging of other malignant diseases such as neuroendocrine tumors, pheochromocytoma, and pancreatic adenocarcinoma expanding its application spectrum. With the application of this tracer in neuroendocrine tumor imaging, improved radiosyntheses have been developed. Among these, the no-carrier-added nucleophilic introduction of fluorine-18, especially, has gained increasing attention as it gives [18F]F-DOPA in higher specific activities and shorter reaction times by less intricate synthesis protocols. The nucleophilic syntheses which were developed recently are able to provide [18F]F-DOPA by automated syntheses in very high specific activities, radiochemical yields, and enantiomeric purities. This review summarizes the developments in the field of [18F]F-DOPA syntheses using electrophilic synthesis pathways as well as recent developments of nucleophilic syntheses of [18F]F-DOPA and compares the different synthesis strategies regarding the accessibility and applicability of the products for human in vivo PET tumor imaging.

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“…In general, these procedures rarely are used, as they are time-consuming because of multi step syntheses and suffer from low yields. 7,8 Most recently, a catalytic enantioselective pathway was described, demonstrating significant improvements. 9 In aromatic compounds nucleophilic substitution generally is hampered by the high electron density of the benzene ring activated by +M effect as in the case of DOPA or tyrosine.…”

Section: Introductionmentioning

confidence: 99%

Electrochemical radiofluorination. 3. Direct labeling of phenylalanine derivatives with [18F]fluoride after anodic oxidation

Kienzle

Reischl

Machulla

2005

J Label Compd Radiopharm

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SummaryAs an example of applying the electrochemical method in radiofluorination a new procedure was developed for preparing [ Best results were obtained for N-trifluoroacetylphenylalanine methyl ester (1) (10.5 AE 2.5%) with a relative isomeric distribution of 50.5 AE 1.5% ortho isomer, 11.5 AE 1.5% meta isomer and 38.8 AE 2.1% para isomer. Optimized reaction conditions were with Et 3 N Á 3HF as supporting electrolyte and temperatures between 0 and -108C. By variation of working potential (1.5-2.0 V) and chloride concentration (added as supporting electrolyte, 0.0-0.36 M) it was demonstrated that an indirect electrolysis as reaction mechanism or a halogen exchange (halex) reaction with primary formation of a chlorinated product followed by halogen exchange are highly improbable.

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Enzymatic synthesis of no-carrier-added 6-[18F]fluoro-l-dopa with β-tyrosinase

Cited by 25 publications

References 17 publications

Electrochemical nucleophilic synthesis of di-tert-butyl-(4-[18F]fluoro-1,2-phenylene)-dicarbonate

Electrochemical nucleophilic synthesis of di-tert-butyl-(4-[18F]fluoro-1,2-phenylene)-dicarbonate

6-[¹⁸F]Fluoro-L-DOPA: A Well-Established Neurotracer with Expanding Application Spectrum and Strongly Improved Radiosyntheses

Electrochemical radiofluorination. 3. Direct labeling of phenylalanine derivatives with [18F]fluoride after anodic oxidation

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Enzymatic synthesis of no-carrier-added 6-[18F]fluoro-l-dopa with β-tyrosinase

Cited by 25 publications

References 17 publications

Electrochemical nucleophilic synthesis of di-tert-butyl-(4-[18F]fluoro-1,2-phenylene)-dicarbonate

Electrochemical nucleophilic synthesis of di-tert-butyl-(4-[18F]fluoro-1,2-phenylene)-dicarbonate

6-[18F]Fluoro-L-DOPA: A Well-Established Neurotracer with Expanding Application Spectrum and Strongly Improved Radiosyntheses

Electrochemical radiofluorination. 3. Direct labeling of phenylalanine derivatives with [18F]fluoride after anodic oxidation

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6-[¹⁸F]Fluoro-L-DOPA: A Well-Established Neurotracer with Expanding Application Spectrum and Strongly Improved Radiosyntheses