Next Article in Journal
A Systematic Review of the Clinical Use of Gabapentin and Pregabalin in Bipolar Disorder
Next Article in Special Issue
Covalent 18F-Radiotracers for SNAPTag: A New Toolbox for Reporter Gene Imaging
Previous Article in Journal
Synthesis, Characterization, and Anticancer Activity of Benzothiazole Aniline Derivatives and Their Platinum (II) Complexes as New Chemotherapy Agents
Previous Article in Special Issue
Labelling via [Al18F]2+ Using Precomplexed Al-NODA Moieties
Article

18F-Fluorination Using Tri-Tert-Butanol Ammonium Iodide as Phase-Transfer Catalyst: An Alternative Minimalist Approach

Department of Nuclear Medicine, Molecular Imaging and Radiochemistry, Friedrich-Alexander University Erlangen-Nürnberg (FAU), D-91054 Erlangen, Germany
*
Author to whom correspondence should be addressed.
These authors contributed equally to this work.
Academic Editor: Irina Velikyan
Pharmaceuticals 2021, 14(9), 833; https://0-doi-org.brum.beds.ac.uk/10.3390/ph14090833
Received: 29 July 2021 / Revised: 17 August 2021 / Accepted: 19 August 2021 / Published: 24 August 2021
The 18F syntheses of tracers for positron emission tomography (PET) typically require several steps, including extraction of [18F]fluoride from H2[18O]O, elution, and drying, prior to nucleophilic substitution reaction, being a laborious and time-consuming process. The elution of [18F]fluoride is commonly achieved by phase transfer catalysts (PTC) in aqueous solution, which makes azeotropic drying indispensable. The ideal PTC is characterized by a slightly basic nature, its capacity to elute [18F]fluoride with anhydrous solvents, and its efficient complex formation with [18F]fluoride during subsequent labeling. Herein, we developed tri-(tert-butanol)-methylammonium iodide (TBMA-I), a quaternary ammonium salt serving as the PTC for 18F-fluorination reactions. The favorable elution efficiency of [18F]fluoride using TBMA-I was demonstrated with aprotic and protic solvents, maintaining high 18F-recoveries of 96–99%. 18F-labeling reactions using TBMA-I as PTC were studied with aliphatic 1,3-ditosylpropane and aryl pinacol boronate esters as precursors, providing 18F-labeled products in moderate-to-high radiochemical yields. TBMA-I revealed adequate properties for application to 18F-fluorination reactions and could be used for elution of [18F]fluoride with MeOH, omitting an additional base and azeotropic drying prior to 18F-labeling. We speculate that the tert-alcohol functionality of TBMA-I promotes intermolecular hydrogen bonding, which enhances the elution efficiency and stability of [18F]fluoride during nucleophilic 18F-fluorination. View Full-Text
Keywords: fluorination; fluorine-18; phase transfer catalyst; copper; radiopharmaceuticals; nucleophilic substitution; 18F-labeling fluorination; fluorine-18; phase transfer catalyst; copper; radiopharmaceuticals; nucleophilic substitution; 18F-labeling
Show Figures

Figure 1

MDPI and ACS Style

Shinde, S.S.; Bolik, K.-V.; Maschauer, S.; Prante, O. 18F-Fluorination Using Tri-Tert-Butanol Ammonium Iodide as Phase-Transfer Catalyst: An Alternative Minimalist Approach. Pharmaceuticals 2021, 14, 833. https://0-doi-org.brum.beds.ac.uk/10.3390/ph14090833

AMA Style

Shinde SS, Bolik K-V, Maschauer S, Prante O. 18F-Fluorination Using Tri-Tert-Butanol Ammonium Iodide as Phase-Transfer Catalyst: An Alternative Minimalist Approach. Pharmaceuticals. 2021; 14(9):833. https://0-doi-org.brum.beds.ac.uk/10.3390/ph14090833

Chicago/Turabian Style

Shinde, Sandip S., Kim-Viktoria Bolik, Simone Maschauer, and Olaf Prante. 2021. "18F-Fluorination Using Tri-Tert-Butanol Ammonium Iodide as Phase-Transfer Catalyst: An Alternative Minimalist Approach" Pharmaceuticals 14, no. 9: 833. https://0-doi-org.brum.beds.ac.uk/10.3390/ph14090833

Find Other Styles
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Back to TopTop