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Zhong X, Yan J, Ding X, Su C, Xu Y, Yang M. Recent Advances in Bioorthogonal Click Chemistry for Enhanced PET and SPECT Radiochemistry. Bioconjug Chem 2023; 34:457-476. [PMID: 36811499 DOI: 10.1021/acs.bioconjchem.2c00583] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
Due to their high reaction rate and reliable selectivity, bioorthogonal click reactions have been extensively investigated in numerous research fields, such as nanotechnology, drug delivery, molecular imaging, and targeted therapy. Previous reviews on bioorthogonal click chemistry for radiochemistry mainly focus on 18F-labeling protocols employed to produce radiotracers and radiopharmaceuticals. In fact, besides fluorine-18, other radionuclides such as gallium-68, iodine-125, and technetium-99m are also used in the field of bioorthogonal click chemistry. Herein, to provide a more comprehensive perspective, we provide a summary of recent advances in radiotracers prepared using bioorthogonal click reactions, including small molecules, peptides, proteins, antibodies, and nucleic acids as well as nanoparticles based on these radionuclides. The combination of pretargeting with imaging modalities or nanoparticles, as well as the clinical translations study, are also discussed to illustrate the effects and potential of bioorthogonal click chemistry for radiopharmaceuticals.
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Affiliation(s)
- Xinlin Zhong
- School of Life Sciences and Health Engineering, Jiangnan University, Wuxi 214122, P. R. China
- School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122, P. R. China
| | - Junjie Yan
- NHC Key Laboratory of Nuclear Medicine, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi 214063, P. R. China
| | - Xiang Ding
- NHC Key Laboratory of Nuclear Medicine, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi 214063, P. R. China
| | - Chen Su
- Wuxi Maternal and Child Health Hospital, Wuxi School of Medicine, Jiangnan University, Wuxi 214002, P. R. China
| | - Yuping Xu
- NHC Key Laboratory of Nuclear Medicine, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi 214063, P. R. China
| | - Min Yang
- School of Life Sciences and Health Engineering, Jiangnan University, Wuxi 214122, P. R. China
- NHC Key Laboratory of Nuclear Medicine, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi 214063, P. R. China
- School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122, P. R. China
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Lozada J, Kuo HT, Lin WX, Lin KS, Bénard F, Perrin DM. Imidazolium-methylene-trifluoroborate: A novel radioprosthetic group validated with preclinical 18 F-Positron Emission Tomography imaging of Prostate Specific Membrane Antigen in mice. J Labelled Comp Radiopharm 2023; 66:130-137. [PMID: 36813569 DOI: 10.1002/jlcr.4020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2022] [Revised: 02/06/2023] [Accepted: 02/08/2023] [Indexed: 02/24/2023]
Abstract
Organotrifluoroborates have gained acceptance as radioprosthetic groups for radiofluorination. Of these, the zwitterionic prosthetic group "AMBF3 " with a quaternary dimethylammonium ion dominates the trifluoroborate space. Herein, we report on imidazolium-methylene trifluoroborate (ImMBF3 ) as an alternative radioprosthetic group and report on its properties in the context of a PSMA-targeting EUK ligand that was previously been conjugated to AMBF3 . The ImMBF3 is readily synthesized from imidazole and conjugated via CuAAC "click" chemistry to give a structure similar to PSMA-617. 18 F-labeling proceeded in one step per our previous reports and imaged in LNCaP-xenograft bearing mice. The [18 F]-PSMA-617-ImMBF3 tracer proved to be less polar (LogP7.4 = -2.95 ± 0.03) while showing a significantly lower solvolytic rate (t1/2 = 8100 min) and slightly higher molar activity (Am) at 174 ± 38 GBq/μmol. Tumor uptake was measured at 13.7 ± 4.8%ID/g and a tumor:muscle ratio of 74.2 ± 35.0, tumor:blood ratio of 21.4 ± 7.0, tumor:kidney ratio of 0.29 ± 0.14, and tumor:bone ratio of 23.5 ± 9.5. In comparison with previously reported PSMA-targeting EUK-AMBF3 conjugates, we have altered the LogP7.4 value, tuned the solvolytic half-life of the prosthetic, and increased radiochemical conversion while achieving similar tumor uptake, contrast ratios, and molar activities compared with AMBF3 bioconjugates.
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Affiliation(s)
- Jerome Lozada
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada
| | - Hsiou-Ting Kuo
- Department of Molecular Oncology, BC Cancer Research Centre, Vancouver, British Columbia, Canada
| | - Wen Xuan Lin
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada
| | - Kuo-Shyan Lin
- Department of Molecular Oncology, BC Cancer Research Centre, Vancouver, British Columbia, Canada
| | - François Bénard
- Department of Molecular Oncology, BC Cancer Research Centre, Vancouver, British Columbia, Canada
| | - David M Perrin
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada
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3
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Abstract
18F-Labeling methods for the preparation of 18F-labeled molecular probes can be classified into electrophilic fluorination, nucleophilic fluorination, metal-F coordination, and 18F/19F isotope exchange. Isotope exchange-based 18F-labeling methods demonstrate mild conditions featuring water resistance and facile high-performance liquid chromatography-free purification in direct 18F-labeling of substrates. This paper systematically reviews isotope exchange-based 18F-labeling methods sorted by the adjacent atom bonding with F, i.e., carbon and noncarbon atoms (Si, B, P, S, Ga, Fe, etc.). The respective isotope exchange mechanism, radiolabeling condition, radiochemical yield, molar activity, and stability of the 18F-product are mainly discussed for each isotope exchange-based 18F-labeling method as well as the cutting-edge application of the corresponding 18F-labeled molecular probes.
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Affiliation(s)
- Tao Wang
- Center for Molecular Imaging and Translational Medicine, State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, Department of Experimental Medicine, School of Public Health, Xiamen University, Xiamen, Fujian 361102, China
| | - Shengji Lv
- Center for Molecular Imaging and Translational Medicine, State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, Department of Experimental Medicine, School of Public Health, Xiamen University, Xiamen, Fujian 361102, China
| | - Zhaobiao Mou
- Center for Molecular Imaging and Translational Medicine, State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, Department of Experimental Medicine, School of Public Health, Xiamen University, Xiamen, Fujian 361102, China
| | - Zhenru Zhang
- Center for Molecular Imaging and Translational Medicine, State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, Department of Experimental Medicine, School of Public Health, Xiamen University, Xiamen, Fujian 361102, China
| | - Taotao Dong
- Center for Molecular Imaging and Translational Medicine, State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, Department of Experimental Medicine, School of Public Health, Xiamen University, Xiamen, Fujian 361102, China
| | - Zijing Li
- Center for Molecular Imaging and Translational Medicine, State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, Department of Experimental Medicine, School of Public Health, Xiamen University, Xiamen, Fujian 361102, China
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Abstract
Fluorescent dyes attached to kinase inhibitors (KIs) can be used to probe kinases in vitro, in cells, and in vivo. Ideal characteristics of the dyes vary with their intended applications. Fluorophores used in vitro may inform on kinase active site environments, hence the dyes used should be small and have minimal impact on modes of binding. These probes may have short wavelength emissions since blue fluorophores are perfectly adequate in this context. Thus, for instance, KI fragments that mimic nucleobases may be modified to be fluorescent with minimal perturbation to the kinase inhibitor structure. However, progressively larger dyes, that emit at longer wavelengths, are required for cellular and in vivo work. In cells, it is necessary to have emissions above autofluorescence of biomolecules, and near infrared dyes are needed to enable excitation and observation through tissue in vivo. This review is organized to describe probes intended for applications in vitro, in cells, then in vivo. The readers will observe that the probes featured tend to become larger and responsive to the near infared end of the spectrum as the review progresses. Readers may also be surprised to realize that relatively few dyes have been used for fluorophore-kinase inhibitor conjugates, and the area is open for innovations in the types of fluorophores used.
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Affiliation(s)
- Syed Muhammad Usama
- Department of Chemistry, Texas A&M University, Box 30012, College Station, TX 77842, USA.
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Fujiki K, Tanaka K. Exploration of the Fluoride Reactivity of Aryltrifluoroborate on Selective Cleavage of Diphenylmethylsilyl Groups. European J Org Chem 2020. [DOI: 10.1002/ejoc.202000707] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Katsumasa Fujiki
- Biofunctional Synthetic Chemistry Laboratory; Cluster for Pioneering Research; RIKEN; 2-1 Hirosawa 351-0198 Wako Saitama Japan
| | - Katsunori Tanaka
- Biofunctional Synthetic Chemistry Laboratory; Cluster for Pioneering Research; RIKEN; 2-1 Hirosawa 351-0198 Wako Saitama Japan
- Biofunctional Chemistry Laboratory; A. Butlerov Institute of Chemistry; Kazan Federal University; 18 Kremlyovskaya street 420008 Kazan Russia
- Department of Chemical Science and Engineering; School of Materials and Chemical Technology; Tokyo Institute of Technology; 2-12-1 O-okayama, Meguro-ku 152-8552 Tokyo Japan
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Narayanam MK, Toutov AA, Murphy JM. Rapid One-Step 18F-Labeling of Peptides via Heteroaromatic Silicon-Fluoride Acceptors. Org Lett 2020; 22:804-808. [DOI: 10.1021/acs.orglett.9b04160] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Maruthi Kumar Narayanam
- Department of Molecular and Medical Pharmacology and Crump Institute for Molecular Imaging, David Geffen School of Medicine, University of California, Los Angeles, 570 Westwood Plaza, Los Angeles, California 90095, United States
| | - Anton A. Toutov
- Fuzionaire Diagnostics, Inc., 177 East Colorado Boulevard, Pasadena, California 91105, United States
| | - Jennifer M. Murphy
- Department of Molecular and Medical Pharmacology and Crump Institute for Molecular Imaging, David Geffen School of Medicine, University of California, Los Angeles, 570 Westwood Plaza, Los Angeles, California 90095, United States
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Chen J, Li C, Hong H, Liu H, Wang C, Xu M, Han Y, Liu Z. Side Chain Optimization Remarkably Enhances the in Vivo Stability of 18F-Labeled Glutamine for Tumor Imaging. Mol Pharm 2019; 16:5035-5041. [PMID: 31670970 DOI: 10.1021/acs.molpharmaceut.9b00891] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Similar to glycolysis, glutaminolysis acts as a vital energy source in tumor cells, providing building blocks for the metabolic needs of tumor cells. To capture glutaminolysis in tumors, 18F-(2S,4R)4-fluoroglutamine ([18F]FGln) and 18F-fluoroboronoglutamine ([18F]FBQ) have been successfully developed for positron emission tomography (PET) imaging, but these two molecules lack stability, resulting in undesired yet significant bone uptake. In this study, we found that [18F]FBQ-C2 is a stable Gln PET tracer by adding two more methylene groups to the side chain of [18F]FBQ. [18F]FBQ-C2 was synthesized with a good radiochemical yield of 35% and over 98% radiochemical purity. [18F]FBQ-C2 showed extreme stability in vitro, and no defluorination was observed after 2 h in phosphate buffered saline at 37 °C. The competitive inhibition assay results indicated that [18F]FBQ-C2 enters cells via the system ASC and N, similar to natural glutamine, and can be transported by tumor-overexpressed ASCT2. PET imaging and biodistribution results indicated that [18F]FBQ-C2 is stable in vivo with low bone uptake (0.81 ± 0.20% ID/g) and can be cleared rapidly from most tissues. Dynamic scan and pharmacokinetic studies using BGC823-xenograft-bearing mice revealed that [18F]FBQ-C2 accumulates specifically in tumors, with a longer half-life (101.18 ± 6.50 min) in tumor tissues than in other tissues (52.70 ± 12.44 min in muscle). Biodistribution exhibits a high tumor-to-normal tissue ratio (4.8 ± 1.7 for the muscle, 2.5 ± 1.0 for the stomach, 2.2 ± 0.9 for the liver, and 17.8 ± 8.4 for the brain). In conclusion, [18F]FBQ-C2 can be used to perform high-contrast Gln imaging of tumors and can serve as a PET tracer for clinical research.
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Affiliation(s)
- Junyi Chen
- Radiochemistry and Radiation Chemistry Key Laboratory of Fundamental Science, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Cong Li
- Peking University-Tsinghua University Center for Life Sciences, Beijing 100871, China
| | - Hanyu Hong
- Radiochemistry and Radiation Chemistry Key Laboratory of Fundamental Science, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Hui Liu
- Radiochemistry and Radiation Chemistry Key Laboratory of Fundamental Science, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Chunhong Wang
- Radiochemistry and Radiation Chemistry Key Laboratory of Fundamental Science, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Mengxin Xu
- Radiochemistry and Radiation Chemistry Key Laboratory of Fundamental Science, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Yuxiang Han
- Radiochemistry and Radiation Chemistry Key Laboratory of Fundamental Science, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Zhibo Liu
- Radiochemistry and Radiation Chemistry Key Laboratory of Fundamental Science, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.,Peking University-Tsinghua University Center for Life Sciences, Beijing 100871, China
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Perrin DM. Organotrifluoroborates as prosthetic groups for Single-Step F18-Labeling of Complex Molecules. Curr Opin Chem Biol 2018; 45:86-94. [DOI: 10.1016/j.cbpa.2018.03.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 02/23/2018] [Accepted: 03/07/2018] [Indexed: 12/11/2022]
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9
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Roxin Á, Zhang C, Huh S, Lepage ML, Zhang Z, Lin KS, Bénard F, Perrin DM. Preliminary evaluation of 18F-labeled LLP2A-trifluoroborate conjugates as VLA-4 (α 4β 1 integrin) specific radiotracers for PET imaging of melanoma. Nucl Med Biol 2018; 61:11-20. [PMID: 29597141 DOI: 10.1016/j.nucmedbio.2018.02.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 02/15/2018] [Accepted: 02/26/2018] [Indexed: 12/11/2022]
Abstract
INTRODUCTION The transmembrane α4β1 integrin receptor, or very-late antigen 4 (VLA-4), is associated with tumor metastasis and angiogenesis, the development of chemotherapeutic drug resistance, and is overexpressed in multiple myelomas, osteosarcomas, lymphomas, leukemias, and melanomas. The peptidomimetic, LLP2A, is a high-affinity ligand with specificity for the extracellular portion of VLA-4 and several conjugates have been evaluated in vivo by NIR-fluorescence, 111In-SPECT and 68Ga- and 64Cu-PET imaging, but to date, not with 18F-PET. METHODS Using two highly stable organotrifluoroborate prosthetic groups: ammoniumdimethyl-trifluoroborate (AMBF3) and a new N-pyridinyl-para-trifluoroborate (N-Pyr-p-BF3), both capable of facile aqueous 18F-labeling by isotope exchange (IEX), we present the first PET imaging evaluations of two [18F]R-BF3--PEG2-LLP2A tracers using VLA-4 overexpressing B16-F10 murine melanoma tumor mouse models. RESULTS Here, we demonstrate successful one-step 18F-labeling of both conjugates with wet NCA [18F]F- in radiochemical yields of up to 11.6% within 75 min at molar activities of 40-100 GBq/μmol. Average tumor uptake values based on ex vivo biodistribution values were 4.4%ID/g (11) and 2.8%ID/g (12) using 18F-labeled LLP2A-conjugates with the two prosthetic groups: N-Pyr-p-BF3 (5) and alkyl-N,N-dimethylammonio-BF3 (AMBF3) (7), respectively, and was found to be target-specific as evidenced by in vivo blocking controls. Dynamic PET scanning and biodistribution studies revealed slow clearance of the [18F]R-BF3--PEG2-LLP2A tracers from the tumors, and also substantial uptake in the intestines, gall bladder, liver and bladder. Observed bone uptake was blockable, consistent with known VLA-4 expression in hematopoietic stem cells found in bone marrow. CONCLUSIONS These studies show that these [18F]R-BF3--PEG2-LLP2A conjugates (11 and 12) are promising VLA-4 targeting radiotracers, yet, further optimization will be required to reduce uptake in the gastro-intestinal tract.
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Affiliation(s)
- Áron Roxin
- Chemistry Department, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
| | - Chengcheng Zhang
- Molecular Oncology, British Columbia Cancer Agency Research Center, 765 West 10th Avenue, Vancouver, British Columbia V5Z 1L3, Canada
| | - Sungjoon Huh
- Chemistry Department, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
| | - Mathieu L Lepage
- Chemistry Department, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
| | - Zhengxing Zhang
- Molecular Oncology, British Columbia Cancer Agency Research Center, 765 West 10th Avenue, Vancouver, British Columbia V5Z 1L3, Canada
| | - Kuo-Shyan Lin
- Molecular Oncology, British Columbia Cancer Agency Research Center, 765 West 10th Avenue, Vancouver, British Columbia V5Z 1L3, Canada
| | - François Bénard
- Molecular Oncology, British Columbia Cancer Agency Research Center, 765 West 10th Avenue, Vancouver, British Columbia V5Z 1L3, Canada
| | - David M Perrin
- Chemistry Department, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada.
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10
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Vabre B, Chansaenpak K, Wang M, Wang H, Li Z, Gabbaï FP. Radiofluorination of a NHC-PF 5 adduct: toward new probes for 18F PET imaging. Chem Commun (Camb) 2017; 53:8657-8659. [PMID: 28731482 DOI: 10.1039/c7cc04402j] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The radiofluorination of N-heterocyclic carbene (NHC) phosphorus(v) fluoride adducts has been investigated. The results show that the IMe-PF5 derivative (IMe = 1,3-dimethylimidazol-2-ylidene) undergoes a Lewis acid promoted 18F-19F isotopic exchange. The resulting radiofluorinated probe is remarkably resistant to hydrolysis both in vitro as well as in vivo.
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Affiliation(s)
- Boris Vabre
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, USA.
| | - Kantapat Chansaenpak
- Department of Radiology, Biomedical Research Imaging Center, University of North Carolina, Chapel Hill 27599, USA. and National Nanotechnology Center (NANOTEC), National Science and Technology Development Agency (NSTDA), 111 Thailand Science Park, Pathum Thani, 12120, Thailand
| | - Mengzhe Wang
- Department of Radiology, Biomedical Research Imaging Center, University of North Carolina, Chapel Hill 27599, USA.
| | - Hui Wang
- Department of Radiology, Biomedical Research Imaging Center, University of North Carolina, Chapel Hill 27599, USA.
| | - Zibo Li
- Department of Radiology, Biomedical Research Imaging Center, University of North Carolina, Chapel Hill 27599, USA.
| | - François P Gabbaï
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, USA.
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11
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Charron CL, Farnsworth AL, Roselt PD, Hicks RJ, Hutton CA. Recent developments in radiolabelled peptides for PET imaging of cancer. Tetrahedron Lett 2016. [DOI: 10.1016/j.tetlet.2016.07.083] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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12
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Walker D, Li Y, Roxin Á, Schaffer P, Adam MJ, Perrin DM. Facile synthesis and 18F-radiolabeling of α 4β 1-specific LLP2A-aryltrifluoroborate peptidomimetic conjugates. Bioorg Med Chem Lett 2016; 26:5126-5131. [PMID: 27623550 DOI: 10.1016/j.bmcl.2016.08.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Revised: 08/04/2016] [Accepted: 08/05/2016] [Indexed: 12/11/2022]
Abstract
The peptidomimetic, LLP2A, is a specific, high-affinity ligand for α4β1 integrin receptors. Previously, several PEGylated LLP2A conjugates were evaluated in vivo as imaging agents for the detection of lymphoma, leukemia, multiple myeloma and melanoma tumours via NIR-fluorescence, 111In-SPECT, and 64Cu- and 68Ga-PET imaging. Despite these successes, to date there is no report of an 18F-labeled LLP2A conjugate. Notably, fluorine-18 is a preferred radionuclide for PET imaging, yet its short half-life and general inactivity under aqueous conditions present challenges for peptide labeling. A simple method for labeling complex biomolecules can be achieved with arylboronic acids that readily capture aqueous [18F]-fluoride ion resulting in an 18F-labeled aryltrifluoroborate ([18F]-ArBF3-) radioprosthetic group. Herein, we present the first radiosynthesis of an 18F-labeled LLP2A conjugate by both one-step 18F-labeling and one-pot two-step 18F-labeling post-'click' conjugation of the 18F-alkynyl-ArBF3- prosthetic. Competition with a fluorescent conjugate of LLP2A demonstrated specific binding of the non-radioactive isotopolog ArBF3--PEG2-LLP2A to α4β1 integrin-expressing MOLT-4 leukemia cells, as evidenced and confirmed by fluorescence microscopy. This work provides a key first step in the development of an expanding library of [18F]-R-BF3--LLP2A radiotracers for PET imaging.
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Affiliation(s)
- Daniel Walker
- Chemistry Department, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
| | - Ying Li
- Chemistry Department, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
| | - Áron Roxin
- Chemistry Department, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
| | - Paul Schaffer
- Triumf, 4004 Wesbrook Mall, Vancouver, BC V6T 2A3, Canada
| | - Michael J Adam
- Triumf, 4004 Wesbrook Mall, Vancouver, BC V6T 2A3, Canada
| | - David M Perrin
- Chemistry Department, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada.
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13
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Perrin DM. [(18)F]-Organotrifluoroborates as Radioprosthetic Groups for PET Imaging: From Design Principles to Preclinical Applications. Acc Chem Res 2016; 49:1333-43. [PMID: 27054808 DOI: 10.1021/acs.accounts.5b00398] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Positron emission tomography (PET) is revolutionizing our ability to visualize in vivo targets for target validation and personalized medicine. Of several classes of imaging agents, peptides afford high affinity and high specificity to distinguish pathologically distinct cell types by the presence of specific molecular targets. Of various available PET isotopes, [(18)F]-fluoride ion is preferred because of its excellent nuclear properties and on-demand production in hospitals at Curie levels. However, the short half-life of (18)F and its lack of reactivity in water continue to challenge peptide labeling. Hence, peptides are often conjugated to a metal chelator for late-stage, one-step labeling. Yet radiometals, while effective, are neither as desirable nor as available as [(18)F]-fluoride ion. Despite considerable past success in identifying semifeasible radiosyntheses, significant challenges continue to confound tracer development. These interrelated challenges relate to (1) isotope/prosthetic choice; (2) bioconjugation for high affinity; (3) high radiochemical yields, (4) specific activities of >1 Ci/μmol to meet FDA microdose requirements; and (5) rapid clearance and in vivo stability. These enduring challenges have been extensively highlighted, while a single-step, operationally simple, and generally applicable means of labeling a peptide with [(18)F]-fluoride ion in good yield and high specific activity has eluded radiochemists and nuclear medicine practitioners for decades. Radiosynthetic ease is of primordial importance since multistep labeling reactions challenge clinical tracer production. In the past decade, as we sought to meet this challenge, appreciation of reactions with aqueous fluoride led us to consider organotrifluoroborate (RBF3(-)) synthesis as a means of rapid aqueous peptide labeling. We have applied principles of mechanistic chemistry, knowledge of chemical reactivity, and synthetic chemistry to design stable RBF3(-)s. Over the past 10 years, we have developed several new [(18)F]-RBF3(-) radioprosthetic groups, all of which guarantee radiosynthetic ease while in most cases providing high tumor:nontumor (T:NT) ratios and moderate-to-high tumor uptake. Although others have developed methods for labeling of peptides with [(18)F]-silylfluorides or [(18)F]-Al-NOTA chelates, this Account focuses on the synthesis of [(18)F]-organotrifluoroborates. In this Account, I detail mechanistic, kinetic, thermodynamic, synthetic, and radiosynthetic approaches that enabled the translation of fundamental principles regarding the chemistry of RBF3(-)s into a tantalizingly close realization of a clinical application of an [(18)F]-organotrifluoroborate-peptide conjugate for imaging of neuroendocrine tumors and the generalization of this method for labeling of several other peptides.
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Affiliation(s)
- David M. Perrin
- Chemistry Department, 2036 Main Mall, University of British Columbia, Vancouver, BC V6T 1Z1, Canada
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14
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Chansaenpak K, Wang H, Wang M, Giglio B, Ma X, Yuan H, Hu S, Wu Z, Li Z. Synthesis and Evaluation of [(18) F]-Ammonium BODIPY Dyes as Potential Positron Emission Tomography Agents for Myocardial Perfusion Imaging. Chemistry 2016; 22:12122-9. [PMID: 27405398 DOI: 10.1002/chem.201601972] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 06/06/2016] [Indexed: 01/06/2023]
Abstract
Recently, we demonstrated the potential of a [(18) F]-trimethylammonium BODIPY dye for cardiac imaging. This is the first example of the use of the [(18) F]-ammonium BODIPY dye for positron emission tomography (PET) myocardial perfusion imaging (MPI). In this report, we extend our study to other ammonium BODIPY dyes with different nitrogen substituents. These novel ammonium BODIPY dyes were successfully prepared and radiolabeled by the SnCl4 -assisted (18) F-(19) F isotopic exchange method. The microPET results and the biodistribution data reveal that nitrogen substituent changes have a significant effect on the in vivo and pharmacological properties of the tracers. Of the novel [(18) F]-ammonium BODIPY dyes prepared in this work, the [(18) F]-dimethylethylammonium BODIPY is superior in terms of myocardium uptake and PET imaging contrast. These results support our hypothesis that the ammonium BODIPY dyes have a great potential for use as PET/optical dual-modality MPI probes.
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Affiliation(s)
- Kantapat Chansaenpak
- Biomedical Research Imaging Center, Department of Radiology, University of North Carolina, Chapel Hill, North Carolina, 27514, USA
| | - Hui Wang
- Biomedical Research Imaging Center, Department of Radiology, University of North Carolina, Chapel Hill, North Carolina, 27514, USA
| | - Mengzhe Wang
- Biomedical Research Imaging Center, Department of Radiology, University of North Carolina, Chapel Hill, North Carolina, 27514, USA
| | - Benjamin Giglio
- Biomedical Research Imaging Center, Department of Radiology, University of North Carolina, Chapel Hill, North Carolina, 27514, USA
| | - Xiaofeng Ma
- Biomedical Research Imaging Center, Department of Radiology, University of North Carolina, Chapel Hill, North Carolina, 27514, USA
| | - Hong Yuan
- Biomedical Research Imaging Center, Department of Radiology, University of North Carolina, Chapel Hill, North Carolina, 27514, USA
| | - Shuo Hu
- PET Center of Xiangya Hospital, Central South University, Changsha, 410008, China.
| | - Zhanhong Wu
- Biomedical Research Imaging Center, Department of Radiology, University of North Carolina, Chapel Hill, North Carolina, 27514, USA.
| | - Zibo Li
- Biomedical Research Imaging Center, Department of Radiology, University of North Carolina, Chapel Hill, North Carolina, 27514, USA
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15
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Chansaenpak K, Wang M, Wu Z, Zaman R, Li Z, Gabbaï FP. [(18)F]-NHC-BF3 adducts as water stable radio-prosthetic groups for PET imaging. Chem Commun (Camb) 2016; 51:12439-42. [PMID: 26144217 DOI: 10.1039/c5cc04545b] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The radiofluorination of N-heterocyclic carbene (NHC) boron trifluoride adducts affords novel [(18)F]-positron emission tomography probes which resist hydrolytic fluoride release. The labelling protocol relies on an (18)F-(19)F isotopic exchange reaction promoted by the Lewis acid SnCl4. Modification of the NHC backbone with a maleimide functionality provides access to a model peptide conjugate which shows no evidence of defluorination when imaged in vivo.
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Affiliation(s)
- Kantapat Chansaenpak
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, USA.
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16
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Zhang Z, Jenni S, Zhang C, Merkens H, Lau J, Liu Z, Perrin DM, Bénard F, Lin KS. Synthesis and evaluation of 18F-trifluoroborate derivatives of triphenylphosphonium for myocardial perfusion imaging. Bioorg Med Chem Lett 2016; 26:1675-9. [DOI: 10.1016/j.bmcl.2016.02.062] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2016] [Revised: 02/18/2016] [Accepted: 02/19/2016] [Indexed: 12/30/2022]
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17
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Chansaenpak K, Wang M, Liu S, Wu Z, Yuan H, Conti PS, Li Z, Gabbaï FP. Synthesis and in vivo stability studies of [18F]-zwitterionic phosphonium aryltrifluoroborate/indomethacin conjugates. RSC Adv 2016. [DOI: 10.1039/c5ra26323a] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Conjugation of ortho-phosphonium phenyltrifluoroborates with indomethacin affords conjugates which have been radiolabeled by 18F–19F isotopic exchange in aqueous solutions and imaged by positron emission tomography in mice.
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Affiliation(s)
| | - Mengzhe Wang
- Department of Radiology
- Biomedical Research Imaging Center
- University of North Carolina
- Chapel Hill 27599
- USA
| | - Shuanglong Liu
- Molecular Imaging Center
- Department of Radiology
- University of Southern California
- Los Angeles 90033
- USA
| | - Zhanhong Wu
- Department of Radiology
- Biomedical Research Imaging Center
- University of North Carolina
- Chapel Hill 27599
- USA
| | - Hong Yuan
- Department of Radiology
- Biomedical Research Imaging Center
- University of North Carolina
- Chapel Hill 27599
- USA
| | - Peter S. Conti
- Molecular Imaging Center
- Department of Radiology
- University of Southern California
- Los Angeles 90033
- USA
| | - Zibo Li
- Department of Radiology
- Biomedical Research Imaging Center
- University of North Carolina
- Chapel Hill 27599
- USA
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18
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Bernard-Gauthier V, Bailey JJ, Liu Z, Wängler B, Wängler C, Jurkschat K, Perrin DM, Schirrmacher R. From Unorthodox to Established: The Current Status of (18)F-Trifluoroborate- and (18)F-SiFA-Based Radiopharmaceuticals in PET Nuclear Imaging. Bioconjug Chem 2015; 27:267-79. [PMID: 26566577 DOI: 10.1021/acs.bioconjchem.5b00560] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Unorthodox (18)F-labeling strategies not employing the formation of a carbon-(18)F bond are seldom found in radiochemistry. Historically, the formation of a boron- or silicon-(18)F bond has been introduced very early on into the repertoire of labeling chemistries, but is without translation into any clinical radiotracer besides inorganic B[(18)F]F4(-) for brain tumor diagnosis. For many decades these labeling methodologies were forgotten and have just recently been revived by a handful of researchers thinking outside the box. When breaking with established paradigms such as the inability to obtain labeled compounds of high specific activity via isotopic exchange or performing radiofluorination in aqueous media, the research community often reacts skeptically. In 2005 and 2006, two novel labeling methodologies were introduced into radiochemistry for positron emission tomography (PET) tracer development: RBF3(-) labeling reported by Perrin et al. and the SiFA methodology by Schirrmacher, Jurkschat, and Waengler et al. which is based on isotopic exchange (IE). Both labeling methodologies have been complemented by other noncanonical strategies to introduce (18)F into biomolecules of diagnostic importance, thus profoundly enriching the landscape of (18)F radiolabeling. B- and Si-based labeling strategies finally revealed that IE is a viable alternative to established and traditional radiochemistry with the advantage of simplifying both the labeling effort as well as the necessary purification of the radiotracer. Hence IE will be the focus of this contribution over other noncanonical labeling methods. Peptides for tumor imaging especially lend themselves favorably toward one-step labeling via IE, but small molecules have been described as well, taking advantage of these new approaches, and have been used successfully for brain imaging. This Review gives an account of both radiochemistries centered on boron and silicon, describing the very beginnings of their basic research, the path that led to optimization of their chemistries, and the first encouraging preclinical results paving the way to their clinical use. This side by side approach will give the reader the opportunity to follow the development of a new basic discovery into a clinically applicable radiotracer including all the hurdles that have had to be overcome.
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Affiliation(s)
- Vadim Bernard-Gauthier
- Division of Oncological Imaging, Department of Oncology, University of Alberta , 11560 University Avenue, Edmonton, Alberta T6G 1Z2, Canada
| | - Justin J Bailey
- Division of Oncological Imaging, Department of Oncology, University of Alberta , 11560 University Avenue, Edmonton, Alberta T6G 1Z2, Canada
| | - Zhibo Liu
- Laboratory of Molecular Imaging and Nanomedicine, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health , 9000 Rockville Pike, Bethesda, Maryland 20892, United States
| | | | | | - Klaus Jurkschat
- Department of Chemistry and Chemical Biology, Technical University of Dortmund , 44227 Dortmund, Germany
| | - David M Perrin
- Department of Chemistry, University of British Columbia , 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
| | - Ralf Schirrmacher
- Division of Oncological Imaging, Department of Oncology, University of Alberta , 11560 University Avenue, Edmonton, Alberta T6G 1Z2, Canada
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19
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Chansaenpak K, Vabre B, Gabbaï FP. [(18)F]-Group 13 fluoride derivatives as radiotracers for positron emission tomography. Chem Soc Rev 2015; 45:954-71. [PMID: 26548467 DOI: 10.1039/c5cs00687b] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The field of (18)F chemistry is rapidly expanding because of the use of this radionuclide in radiotracers for positron emission tomography (PET). Until recently, most [(18)F]-radiotracers were generated by the direct attachment of (18)F to a carbon in the organic backbone of the radiotracer. The past decade has witnessed the emergence of a new strategy based on the formation of an (18)F-group 13 element bond. This approach, which is rooted in the field of fluoride anion complexation/coordination chemistry, has led to the development of a remarkable family of boron, aluminium and gallium [(18)F]-fluoride anion complexing agents which can be conjugated with peptides and small molecules to generate disease specific PET radiotracers. This review is dedicated to the chemistry of these group 13 [(18)F]-fluorides anion complexing agents and their use in PET. Some of the key fluoride-binding motifs covered in this review include the trifluoroborate unit bound to neutral or cationic electron deficient backbones, the BF2 unit of BODIPY dyes, and AlF or GaF3 units coordinated to multidentate Lewis basic ligands. In addition to describing how these moieties can be converted into their [(18)F]-analogs, this review also dicusses their incorporation into bioconjugates for application in PET.
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Affiliation(s)
- Kantapat Chansaenpak
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, USA.
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20
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Liu Z, Lin KS, Bénard F, Pourghiasian M, Kiesewetter DO, Perrin DM, Chen X. One-step (18)F labeling of biomolecules using organotrifluoroborates. Nat Protoc 2015; 10:1423-32. [PMID: 26313478 PMCID: PMC5223096 DOI: 10.1038/nprot.2015.090] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Herein we present a general protocol for the functionalization of biomolecules with an organotrifluoroborate moiety so that they can be radiolabeled with aqueous (18)F fluoride ((18)F(-)) and used for positron emission tomography (PET) imaging. Among the β(+)-emitting radionuclides, fluorine-18 ((18)F) is the isotope of choice for PET, and it is produced, on-demand, in many hospitals worldwide. Organotrifluoroborates can be (18)F-labeled in one step in aqueous conditions via (18)F-(19)F isotope exchange. This protocol features a recently designed ammoniomethyltrifluoroborate, and it describes the following: (i) a synthetic strategy that affords modular synthesis of radiolabeling precursors via a copper-catalyzed 'click' reaction; and (ii) a one-step (18)F-labeling method that obviates the need for HPLC purification. Within 30 min, (18)F-labeled PET imaging probes, such as peptides, can be synthesized in good chemical and radiochemical purity (>98%), satisfactory radiochemical yield of 20-35% (n > 20, non-decay corrected) and high specific activity of 40-111 GBq/μmol (1.1-3.0 Ci/μmol). The entire procedure, including the precursor preparation and (18)F radiolabeling, takes 7-10 d.
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Affiliation(s)
- Zhibo Liu
- Laboratory of Molecular Imaging and Nanomedicine, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, Maryland, USA
| | - Kuo-Shyan Lin
- Department of Molecular Oncology, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
| | - François Bénard
- Department of Molecular Oncology, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
| | - Maral Pourghiasian
- Department of Molecular Oncology, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
| | - Dale O Kiesewetter
- Laboratory of Molecular Imaging and Nanomedicine, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, Maryland, USA
| | - David M Perrin
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada
| | - Xiaoyuan Chen
- Laboratory of Molecular Imaging and Nanomedicine, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, Maryland, USA
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21
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Bernard J, Malacea-Kabbara R, Clemente GS, Burke BP, Eymin MJ, Archibald SJ, Jugé S. o-Boronato- and o-Trifluoroborato–Phosphonium Salts Supported by l-α-Amino Acid Side Chain. J Org Chem 2015; 80:4289-98. [DOI: 10.1021/acs.joc.5b00246] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Julie Bernard
- Institut de Chimie Moléculaire de l’Université de Bourgogne (ICMUB) StéréochIM UMR CNRS 6302, 9 Avenue A. Savary BP 47870, 21078 Dijon Cedex, France
| | - Raluca Malacea-Kabbara
- Institut de Chimie Moléculaire de l’Université de Bourgogne (ICMUB) StéréochIM UMR CNRS 6302, 9 Avenue A. Savary BP 47870, 21078 Dijon Cedex, France
| | - Gonçalo S. Clemente
- Department
of Chemistry and Positron Emission Tomography Research Centre, University of Hull, Cottingham Road, Hull, East
Yorkshire HU6 7RX, United Kingdom
| | - Benjamin P. Burke
- Department
of Chemistry and Positron Emission Tomography Research Centre, University of Hull, Cottingham Road, Hull, East
Yorkshire HU6 7RX, United Kingdom
| | - Marie-Joëlle Eymin
- Institut de Chimie Moléculaire de l’Université de Bourgogne (ICMUB) StéréochIM UMR CNRS 6302, 9 Avenue A. Savary BP 47870, 21078 Dijon Cedex, France
| | - Stephen J. Archibald
- Department
of Chemistry and Positron Emission Tomography Research Centre, University of Hull, Cottingham Road, Hull, East
Yorkshire HU6 7RX, United Kingdom
| | - Sylvain Jugé
- Institut de Chimie Moléculaire de l’Université de Bourgogne (ICMUB) StéréochIM UMR CNRS 6302, 9 Avenue A. Savary BP 47870, 21078 Dijon Cedex, France
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22
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Liu Z, Chao D, Li Y, Ting R, Oh J, Perrin DM. From Minutes to Years: Predicting Organotrifluoroborate Solvolysis Rates. Chemistry 2015; 21:3924-8. [DOI: 10.1002/chem.201405829] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Indexed: 01/22/2023]
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23
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Liu Z, Li Y, Ting R, Perrin DM. Designing kinetically stable aryltrifluoroborates as 18
F-capture agents for PET imaging. J PHYS ORG CHEM 2015. [DOI: 10.1002/poc.3403] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Zhibo Liu
- Chemistry Department; BC; 2036 Main Mall V6T1Z1 Canada
| | - Ying Li
- Chemistry Department; BC; 2036 Main Mall V6T1Z1 Canada
| | - Richard Ting
- Chemistry Department; BC; 2036 Main Mall V6T1Z1 Canada
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24
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Liu Z, Pourghiasian M, Radtke MA, Lau J, Pan J, Dias GM, Yapp D, Lin KS, Bénard F, Perrin DM. An Organotrifluoroborate for Broadly Applicable One-Step18F-Labeling. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201406258] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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25
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Liu Z, Pourghiasian M, Radtke MA, Lau J, Pan J, Dias GM, Yapp D, Lin KS, Bénard F, Perrin DM. An organotrifluoroborate for broadly applicable one-step 18F-labeling. Angew Chem Int Ed Engl 2014; 53:11876-80. [PMID: 25196467 DOI: 10.1002/anie.201406258] [Citation(s) in RCA: 126] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Indexed: 11/12/2022]
Abstract
A new zwitterionic organotrifluoroborate is appended to three radiosynthons that afford undergo facile bioconjugation to several clinically relevant peptides and one enzyme inhibitor. Molecularly complex bioconjugates are (18)F-labeled in a single aqueous step in rapid time (<15 min) without HPLC purification to afford tracers in good yields (>200 mCi, 20-40%) at high specific activity (≥3 Ci/μmol) and at >98% purity. PET imaging shows in vivo stability and tumor uptake.
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Affiliation(s)
- Zhibo Liu
- Chemistry Department, University of British Columbia, 2036 Main Mall, Vancouver, BC, V6T-1Z1 (Canada)
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26
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Burke BP, Clemente GS, Archibald SJ. Boron-18F containing positron emission tomography radiotracers: advances and opportunities. CONTRAST MEDIA & MOLECULAR IMAGING 2014; 10:96-110. [DOI: 10.1002/cmmi.1615] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Revised: 06/14/2014] [Accepted: 06/26/2014] [Indexed: 12/27/2022]
Affiliation(s)
- Benjamin P. Burke
- Department of Chemistry; University of Hull; Hull HU6 7RX UK
- Positron Emission Tomography Research Centre; University of Hull; Hull HU6 7RX UK
| | - Gonçalo S. Clemente
- Positron Emission Tomography Research Centre; University of Hull; Hull HU6 7RX UK
| | - Stephen J. Archibald
- Department of Chemistry; University of Hull; Hull HU6 7RX UK
- Positron Emission Tomography Research Centre; University of Hull; Hull HU6 7RX UK
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27
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Lozada J, Liu Z, Perrin DM. Base-promoted protodeboronation of 2,6-disubstituted arylboronic acids. J Org Chem 2014; 79:5365-8. [PMID: 24826787 DOI: 10.1021/jo500734z] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Facile based promoted deboronation of electron-deficient arylboronate esters was observed for arylboronates containing two ortho electron-withdrawing group (EWG) substituents. Among 30 representative boronates, only the diortho-substituted species underwent facile C-B fission in aqueous basic conditions (200 mM hydroxide). These results provide fundamental insight into deboronative mechanisms with implications for cross-coupling reactions, regioselective deuteration/tritiation for isotopic labeling, and the design of new (18)F-trifluoroborate radioprosthetics.
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Affiliation(s)
- Jerome Lozada
- Department of Chemistry, University of British Columbia , Vancouver BC, Canada
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