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Bratteby K, Shalgunov V, Battisti UM, Petersen IN, van den Broek SL, Ohlsson T, Gillings N, Erlandsson M, Herth MM. Insights into Elution of Anion Exchange Cartridges: Opening the Path toward Aliphatic 18F-Radiolabeling of Base-Sensitive Tracers. ACS Pharmacol Transl Sci 2021; 4:1556-1566. [PMID: 34661074 PMCID: PMC8506604 DOI: 10.1021/acsptsci.1c00133] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Indexed: 01/16/2023]
Abstract
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Aliphatic nucleophilic
substitution (SN2) with [18F]fluoride is the
most widely applied method to prepare 18F-labeled positron
emission tomography (PET) tracers. Strong
basic conditions commonly used during 18F-labeling procedures
inherently limit or prohibit labeling of base-sensitive scaffolds.
The high basicity stems from the tradition to trap [18F]fluoride
on anion exchange cartridges and elute it afterward with basic anions.
This sequence is used to facilitate the transfer of [18F]fluoride from an aqueous to an aprotic organic, polar reaction
medium, which is beneficial for SN2 reactions. Furthermore,
this sequence also removes cationic radioactive contaminations from
cyclotron-irradiated [18O]water from which [18F]fluoride is produced. In this study, we developed an efficient
elution procedure resulting in low basicity that permits SN2 18F-labeling of base-sensitive scaffolds. Extensive
screening of trapping and elution conditions (>1000 experiments)
and
studying their influence on the radiochemical yield (RCY) allowed
us to identify a suitable procedure for this. Using this procedure,
four PET tracers and three synthons could be radiolabeled in substantially
higher RCYs (up to 2.5-fold) compared to those of previously published
procedures, even from lower precursor amounts. Encouraged by these
results, we applied our low-basicity method to the radiolabeling of
highly base-sensitive tetrazines, which cannot be labeled using state-of-art
direct aliphatic 18F-labeling procedures. Labeling succeeded
in RCYs of up to 20%. We believe that our findings facilitate PET
tracer development by opening the path toward simple and direct SN2 18F fluorination of base-sensitive substrates.
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Affiliation(s)
- Klas Bratteby
- Department of Drug Design and Pharmacology, University of Copenhagen, Jagtvej 160, 2100 Copenhagen, Denmark.,Department of Radiation Physics, Skåne University Hospital, Barngatan 3, 22242 Lund, Sweden.,Department of Clinical Physiology Nuclear Medicine & PET, Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen, Denmark
| | - Vladimir Shalgunov
- Department of Drug Design and Pharmacology, University of Copenhagen, Jagtvej 160, 2100 Copenhagen, Denmark.,Department of Clinical Physiology Nuclear Medicine & PET, Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen, Denmark
| | - Umberto Maria Battisti
- Department of Drug Design and Pharmacology, University of Copenhagen, Jagtvej 160, 2100 Copenhagen, Denmark
| | - Ida Nyman Petersen
- Department of Clinical Physiology Nuclear Medicine & PET, Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen, Denmark
| | - Sara Lopes van den Broek
- Department of Drug Design and Pharmacology, University of Copenhagen, Jagtvej 160, 2100 Copenhagen, Denmark
| | - Tomas Ohlsson
- Department of Radiation Physics, Skåne University Hospital, Barngatan 3, 22242 Lund, Sweden
| | - Nic Gillings
- Department of Clinical Physiology Nuclear Medicine & PET, Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen, Denmark
| | - Maria Erlandsson
- Department of Radiation Physics, Skåne University Hospital, Barngatan 3, 22242 Lund, Sweden
| | - Matthias M Herth
- Department of Drug Design and Pharmacology, University of Copenhagen, Jagtvej 160, 2100 Copenhagen, Denmark.,Department of Clinical Physiology Nuclear Medicine & PET, Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen, Denmark
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Lau J, Rousseau J, Kwon D, Bénard F, Lin KS. A Systematic Review of Molecular Imaging Agents Targeting Bradykinin B1 and B2 Receptors. Pharmaceuticals (Basel) 2020; 13:ph13080199. [PMID: 32824565 PMCID: PMC7464927 DOI: 10.3390/ph13080199] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 08/11/2020] [Accepted: 08/13/2020] [Indexed: 12/22/2022] Open
Abstract
Kinins, bradykinin and kallidin are vasoactive peptides that signal through the bradykinin B1 and B2 receptors (B1R and B2R). B2R is constitutively expressed in healthy tissues and mediates responses such as vasodilation, fluid balance and retention, smooth muscle contraction, and algesia, while B1R is absent in normal tissues and is induced by tissue trauma or inflammation. B2R is activated by kinins, while B1R is activated by kinins that lack the C-terminal arginine residue. Perturbations of the kinin system have been implicated in inflammation, chronic pain, vasculopathy, neuropathy, obesity, diabetes, and cancer. In general, excess activation and signaling of the kinin system lead to a pro-inflammatory state. Depending on the disease context, agonism or antagonism of the bradykinin receptors have been considered as therapeutic options. In this review, we summarize molecular imaging agents targeting these G protein-coupled receptors, including optical and radioactive probes that have been used to interrogate B1R/B2R expression at the cellular and anatomical levels, respectively. Several of these preclinical agents, described herein, have the potential to guide therapeutic interventions for these receptors.
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Affiliation(s)
- Joseph Lau
- Department of Molecular Oncology, BC Cancer, Vancouver, BC V5Z 1L3 Canada
| | - Julie Rousseau
- Department of Molecular Oncology, BC Cancer, Vancouver, BC V5Z 1L3 Canada
| | - Daniel Kwon
- Department of Molecular Oncology, BC Cancer, Vancouver, BC V5Z 1L3 Canada
| | - François Bénard
- Department of Molecular Oncology, BC Cancer, Vancouver, BC V5Z 1L3 Canada
- Department of Radiology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Kuo-Shyan Lin
- Department of Molecular Oncology, BC Cancer, Vancouver, BC V5Z 1L3 Canada
- Department of Radiology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
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Kwon YD, Jeon MH, Park NK, Seo JK, Son J, Ryu YH, Hong SY, Chun JH. Synthesis of 18F-Labeled Aryl Fluorosulfates via Nucleophilic Radiofluorination. Org Lett 2020; 22:5511-5516. [PMID: 32589035 DOI: 10.1021/acs.orglett.0c01868] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Sulfuryl fluoride gas is a key reagent for SO2F transfer. However, conventional SO2F transfer reactions have limited 18F-radiochemistry translation, due to the inaccessibility of gaseous [18F]SO2F2. Herein, we report the first SO2F2-free synthesis of aryl [18F]fluorosulfates from both phenolic and isolated aryl imidazylate precursors with cyclotron-produced 18F-. The radiochemical yields ranged from moderate to good with excellent functional group tolerance. The reliability of our approach was validated by the automated radiosynthesis of 4-acetamidophenyl [18F]fluorosulfate.
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Affiliation(s)
- Young-Do Kwon
- Department of Nuclear Medicine, Yonsei University College of Medicine, Seoul 03722, Republic of Korea
| | - Min Ho Jeon
- Department of Chemistry, School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Nam Kyu Park
- Department of Chemistry, School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Jeong Kon Seo
- UNIST Central Research Facility, Ulsan 44919, Republic of Korea
| | - Jeongmin Son
- Department of Nuclear Medicine, Yonsei University Health System, Seoul 03722, Republic of Korea
| | - Young Hoon Ryu
- Department of Nuclear Medicine, Yonsei University College of Medicine, Seoul 03722, Republic of Korea.,Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul 06273, Republic of Korea
| | - Sung You Hong
- Department of Chemistry, School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Joong-Hyun Chun
- Department of Nuclear Medicine, Yonsei University College of Medicine, Seoul 03722, Republic of Korea
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Radical C–H 18F-Difluoromethylation of Heteroarenes with [18F]Difluoromethyl Heteroaryl-Sulfones by Visible Light Photoredox Catalysis. Catalysts 2020. [DOI: 10.3390/catal10030275] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The 18F-labeling of CF2H groups has been recently studied in radiopharmaceutical chemistry owing to the favorable nuclear and physical characteristics of the radioisotope 18F for positron emission tomography (PET). Following up on the reported efficiency of the [18F]difluoromethyl benzothiazolyl-sulfone ([18F]1) as a 18F-difluoromethylating reagent, we investigated the influence of structurally-related [18F]difluoromethyl heteroaryl-sulfones in the reactivity toward the photoredox C–H 18F-difluoromethylation of heteroarenes under continuous-flow conditions. In the present work, six new [18F]difluoromethyl heteroaryl-sulfones [18F]5a–[18F]5f were prepared and, based on the overall radiochemical yields (RCYs), three of these reagents ([18F]5a, [18F]5c, and [18F]5f) were selected for the fully automated radiosynthesis on a FASTlabTM synthesizer (GE Healthcare) at high level of starting radioactivity. Subsequently, their efficiency as 18F-difluoromethylating reagents was evaluated using the antiherpetic drug acyclovir as a model substrate. Our results showed that the introduction of molecular modifications in the structure of [18F]1 influenced the amount of fac-IrIII(ppy)3 and the residence time needed to ensure a complete C–H 18F-difluoromethylation process. The photocatalytic C–H 18F-difluoromethylation reaction with the reagents [18F]5a, [18F]5c, and [18F]5f was extended to other heteroarenes. Radical-trapping experiments demonstrated the likely involvement of radical species in the C–H 18F-difluoromethylation process.
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Zhan X, Yadav P, Diskin-Posner Y, Fridman N, Sundararajan M, Ullah Z, Chen QC, Shimon LJW, Mahammed A, Churchill DG, Baik MH, Gross Z. Positive shift in corrole redox potentials leveraged by modest β-CF3-substitution helps achieve efficient photocatalytic C–H bond functionalization by group 13 complexes. Dalton Trans 2019; 48:12279-12286. [DOI: 10.1039/c9dt02150g] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Tris- and tetrakis-β-trifluoromethylated gallium (3CF3-Ga, 4CF3-Ga) and aluminum (3CF3-Al, 4CF3-Al) corrole systems were synthesized by a facile “one-pot” approach and studied in the context of photocatalytic C–H bond activation.
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