1
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Ford J, Ortalli S, Gouverneur V. The 18F-Difluoromethyl Group: Challenges, Impact and Outlook. Angew Chem Int Ed Engl 2024; 63:e202404957. [PMID: 38640422 DOI: 10.1002/anie.202404957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Revised: 04/18/2024] [Accepted: 04/19/2024] [Indexed: 04/21/2024]
Abstract
The difluoromethyl functionality has proven useful in drug discovery, as it can modulate the properties of bioactive molecules. For PET imaging, this structural motif has been largely underexploited in (pre)clinical radiotracers due to a lack of user-friendly radiosynthetic routes. This Minireview provides an overview of the challenges facing radiochemists and summarises the efforts made to date to access 18F-difluoromethyl-containing radiotracers. Two distinct approaches have prevailed, the first of which relies on 18F-fluorination. A second approach consists of a 18F-difluoromethylation process, which uses 18F-labelled reagents capable of releasing key reactive intermediates such as the [18F]CF2H radical or [18F]difluorocarbene. Finally, we provide an outlook for future directions in the radiosynthesis of [18F]CF2H compounds and their application in tracer radiosynthesis.
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Affiliation(s)
- Joseph Ford
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, United Kingdom
| | - Sebastiano Ortalli
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, United Kingdom
| | - Véronique Gouverneur
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, United Kingdom
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2
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Xue JH, Li Y, Liu Y, Li Q, Wang H. Site-Specific Deaminative Trifluoromethylation of Aliphatic Primary Amines. Angew Chem Int Ed Engl 2024; 63:e202319030. [PMID: 38179851 DOI: 10.1002/anie.202319030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 01/02/2024] [Accepted: 01/03/2024] [Indexed: 01/06/2024]
Abstract
The introduction of trifluoromethyl groups into organic molecules is of paramount importance in modern synthetic chemistry and medicinal chemistry. While methods for constructing C(sp2 )-CF3 bonds have been well established, the advancement of practical and comprehensive approaches for forming C(sp3 )-CF3 bonds remains considerably restricted. In this work, we describe an efficient and site-specific deaminative trifluoromethylation reaction of aliphatic primary amines to afford the corresponding alkyl trifluoromethyl compounds. The reaction proceeds at room temperature with readily accessible N-anomeric amide (Levin's reagent) and bench-stable bpyCu(CF3 )3 (Grushin's reagent, bpy=2,2'-bipyridine) under blue light. The protocol features mild reaction conditions, good functional group tolerance, and moderate to good yields. Remarkably, the method can be applied to the direct, late-stage trifluoromethylation of natural products and bioactive molecules. Experimental mechanistic studies were conducted, and a radical mechanism is proposed, wherein the dual roles of Grushin's reagent have been elucidated.
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Affiliation(s)
- Jiang-Hao Xue
- Guangdong Provincial Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou, 510006, China
| | - Yin Li
- Guangdong Provincial Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou, 510006, China
| | - Yuan Liu
- Guangdong Provincial Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou, 510006, China
| | - Qingjiang Li
- Guangdong Provincial Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou, 510006, China
| | - Honggen Wang
- Guangdong Provincial Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou, 510006, China
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3
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Lu S, Telu S, Siméon FG, Cai L, Pike VW. Gas Phase Transformations in Carbon-11 Chemistry. Int J Mol Sci 2024; 25:1167. [PMID: 38256240 PMCID: PMC10816134 DOI: 10.3390/ijms25021167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 01/10/2024] [Accepted: 01/11/2024] [Indexed: 01/24/2024] Open
Abstract
The short-lived positron-emitter carbon-11 (t1/2 = 20.4 min; β+, 99.8%) is prominent for labeling tracers for use in biomedical research with positron emission tomography (PET). Carbon-11 is produced for this purpose with a cyclotron, nowadays almost exclusively by the 14N(p,α)11C nuclear reaction, either on nitrogen containing a low concentration of oxygen (0.1-0.5%) or hydrogen (~5%) to produce [11C]carbon dioxide or [11C]methane, respectively. These primary radioactive products can be produced in high yields and with high molar activities. However, only [11C]carbon dioxide has some utility for directly labeling PET tracers. Primary products are required to be converted rapidly and efficiently into secondary labeling synthons to provide versatile radiochemistry for labeling diverse tracer chemotypes at molecular positions of choice. This review surveys known gas phase transformations of carbon-11 and summarizes the important roles that many of these transformations now play for producing a broad range of labeling synthons in carbon-11 chemistry.
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Affiliation(s)
| | | | | | | | - Victor W. Pike
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Rm B3C346, 10 Center Drive, Bethesda, MD 20892-1003, USA; (S.L.); (S.T.); (F.G.S.); (L.C.)
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Wang W, Chamoreau LM, Izzet G, Proust A, Orio M, Blanchard S. Multi-Electron Visible Light Photoaccumulation on a Dipyridylamine Copper(II)-Polyoxometalate Conjugate Applied to Photocatalytic Generation of CF 3 Radicals. J Am Chem Soc 2023. [PMID: 37216360 DOI: 10.1021/jacs.3c01716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
This article describes the synthesis and characterization of an organic-inorganic hybrid polyoxometalate functionalized by a short link with a tripodal N-based ligand and its copper complex. Upon visible light irradiation, the latter is able to store up to three reducing equivalents. The locus of the reduction is discussed based on physicochemical measurements and DFT calculations. In the presence of Togni's reagent, this complex allows for the photocatalytic generation of CF3 radicals, opening the road to valuable synthetic applications.
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Affiliation(s)
- Weixian Wang
- Institut Parisien de Chimie Moléculaire, Sorbonne Université, CNRS, F-75005 Paris, France
| | - Lise-Marie Chamoreau
- Institut Parisien de Chimie Moléculaire, Sorbonne Université, CNRS, F-75005 Paris, France
| | - Guillaume Izzet
- Institut Parisien de Chimie Moléculaire, Sorbonne Université, CNRS, F-75005 Paris, France
| | - Anna Proust
- Institut Parisien de Chimie Moléculaire, Sorbonne Université, CNRS, F-75005 Paris, France
| | - Maylis Orio
- Aix Marseille Université, CNRS, Centrale Marseille, iSm2, UMR CNRS 7313, 13397 Marseille, France
| | - Sébastien Blanchard
- Institut Parisien de Chimie Moléculaire, Sorbonne Université, CNRS, F-75005 Paris, France
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Webb EW, Cheng K, Wright JS, Cha J, Shao X, Sanford MS, Scott PJH. Room-Temperature Copper-Mediated Radiocyanation of Aryldiazonium Salts and Aryl Iodides via Aryl Radical Intermediates. J Am Chem Soc 2023; 145:6921-6926. [PMID: 36917154 PMCID: PMC10065967 DOI: 10.1021/jacs.3c00422] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023]
Abstract
Radiocyanation is an attractive strategy for incorporating carbon-11 into radiotracer targets, particularly given the broad scope of acyl moieties accessible from nitriles. Most existing methods for aromatic radiocyanation require elevated temperatures (Cu-mediated reactions of aryl halides or organometallics) or involve expensive and toxic palladium complexes (Pd-mediated reactions of aryl halides). The current report discloses a complementary approach that leverages the capture of aryl radical intermediates by a Cu-11CN complex to achieve rapid and mild (5 min, room temperature) radiocyanation. In a first example, aryl radicals are generated via the reaction of a CuI mediator with an aryldiazonium salt (a Sandmeyer-type reaction) followed by radiocyanation with Cu-11CN. In a second example, aryl radicals are formed from aryl iodides via visible-light photocatalysis and then captured by a Cu-11CN species to achieve aryl-11CN coupling. This approach provides access to radiocyanated products that are challenging to access using other methods (e.g., ortho-disubstituted aryl nitriles).
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Affiliation(s)
- E. William Webb
- Department of Radiology, University of Michigan Medical School, 1301 Catherine Street, Ann Arbor, Michigan 48109, United States
| | - Kevin Cheng
- Department of Radiology, University of Michigan Medical School, 1301 Catherine Street, Ann Arbor, Michigan 48109, United States
| | - Jay S. Wright
- Department of Radiology, University of Michigan Medical School, 1301 Catherine Street, Ann Arbor, Michigan 48109, United States
| | - Jocelyn Cha
- Department of Radiology, University of Michigan Medical School, 1301 Catherine Street, Ann Arbor, Michigan 48109, United States
| | - Xia Shao
- Department of Radiology, University of Michigan Medical School, 1301 Catherine Street, Ann Arbor, Michigan 48109, United States
| | - Melanie S. Sanford
- Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
| | - Peter J. H. Scott
- Department of Radiology, University of Michigan Medical School, 1301 Catherine Street, Ann Arbor, Michigan 48109, United States
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Pees A, Chassé M, Lindberg A, Vasdev N. Recent Developments in Carbon-11 Chemistry and Applications for First-In-Human PET Studies. Molecules 2023; 28:molecules28030931. [PMID: 36770596 PMCID: PMC9920299 DOI: 10.3390/molecules28030931] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 01/09/2023] [Accepted: 01/10/2023] [Indexed: 01/19/2023] Open
Abstract
Positron emission tomography (PET) is a molecular imaging technique that makes use of radiolabelled molecules for in vivo evaluation. Carbon-11 is a frequently used radionuclide for the labelling of small molecule PET tracers and can be incorporated into organic molecules without changing their physicochemical properties. While the short half-life of carbon-11 (11C; t½ = 20.4 min) offers other advantages for imaging including multiple PET scans in the same subject on the same day, its use is limited to facilities that have an on-site cyclotron, and the radiochemical transformations are consequently more restrictive. Many researchers have embraced this challenge by discovering novel carbon-11 radiolabelling methodologies to broaden the synthetic versatility of this radionuclide. This review presents new carbon-11 building blocks and radiochemical transformations as well as PET tracers that have advanced to first-in-human studies over the past five years.
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Affiliation(s)
- Anna Pees
- Azrieli Centre for Neuro-Radiochemistry, Brain Health Imaging Centre, Centre for Addiction and Mental Health (CAMH), Toronto, ON M5T 1R8, Canada
| | - Melissa Chassé
- Azrieli Centre for Neuro-Radiochemistry, Brain Health Imaging Centre, Centre for Addiction and Mental Health (CAMH), Toronto, ON M5T 1R8, Canada
- Institute of Medical Science, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Anton Lindberg
- Azrieli Centre for Neuro-Radiochemistry, Brain Health Imaging Centre, Centre for Addiction and Mental Health (CAMH), Toronto, ON M5T 1R8, Canada
| | - Neil Vasdev
- Azrieli Centre for Neuro-Radiochemistry, Brain Health Imaging Centre, Centre for Addiction and Mental Health (CAMH), Toronto, ON M5T 1R8, Canada
- Institute of Medical Science, University of Toronto, Toronto, ON M5S 1A8, Canada
- Department of Psychiatry, University of Toronto, Toronto, ON M5T 1R8, Canada
- Correspondence:
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7
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Luo Z, Cahard D, Tsui GC. Using Fluoroform in Trifluoromethylation Reactions. J Fluor Chem 2023. [DOI: 10.1016/j.jfluchem.2023.110092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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8
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Siméon FG, Lee JH, Morse CL, Stukes I, Zoghbi SS, Manly LS, Liow JS, Gladding RL, Dick RM, Yan X, Taliani S, Costa B, Martini C, Da Settimo F, Castellano S, Innis RB, Pike VW. Synthesis and Screening in Mice of Fluorine-Containing PET Radioligands for TSPO: Discovery of a Promising 18F-Labeled Ligand. J Med Chem 2021; 64:16731-16745. [PMID: 34756026 PMCID: PMC8817670 DOI: 10.1021/acs.jmedchem.1c01562] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Translocator protein 18 kDa (TSPO) is a biomarker of neuroinflammation. [11C]ER176 robustly quantifies TSPO in the human brain with positron emission tomography (PET), irrespective of subject genotype. We aimed to develop an ER176 analog with potential for labeling with longer-lived fluorine-18 (t1/2 = 109.8 min). New fluoro and trifluoromethyl analogs of ER176 were prepared through a concise synthetic strategy. These ligands showed high TSPO affinity and low human genotype sensitivity. Each ligand was initially labeled by a generic 11C-methylation procedure, thereby enabling speedy screening in mice. Each radioligand was rapidly taken up and well retained in the mouse brain at baseline after intravenous injection. Preblocking of TSPO showed that high proportions of brain uptake were specifically bound to TSPO at baseline. Overall, the 3-fluoro analog of [11C]ER176 ([11C]3b) displayed the most promising imaging properties. Therefore, a method was developed to label 3b with [18F]fluoride ion. [18F]3b gave similarly promising PET imaging results and deserves evaluation in higher species.
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Affiliation(s)
- Fabrice G Siméon
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Jae-Hoon Lee
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892, United States
- Department of Nuclear Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul 03772, South Korea
| | - Cheryl L Morse
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Ian Stukes
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Sami S Zoghbi
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Lester S Manly
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Jeih-San Liow
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Robert L Gladding
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Rachel M Dick
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Xuefeng Yan
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Sabrina Taliani
- Department of Pharmacy, University of Pisa, 56126 Pisa, Italy
| | - Barbara Costa
- Department of Pharmacy, University of Pisa, 56126 Pisa, Italy
| | - Claudia Martini
- Department of Pharmacy, University of Pisa, 56126 Pisa, Italy
| | | | - Sabrina Castellano
- Department of Pharmacy, University of Salerno, 84084 Fisciano, SA, Italy
| | - Robert B Innis
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Victor W Pike
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892, United States
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9
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Li Y, Zhang CL, Huang WH, Sun N, Hao M, Neumann H, Beller M. A general strategy for the synthesis of α-trifluoromethyl- and α-perfluoroalkyl-β-lactams via palladium-catalyzed carbonylation. Chem Sci 2021; 12:10467-10473. [PMID: 34447539 PMCID: PMC8361786 DOI: 10.1039/d1sc02212a] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 06/30/2021] [Indexed: 11/30/2022] Open
Abstract
β-Lactam compounds play a key role in medicinal chemistry, specifically as the most important class of antibiotics. Here, we report a novel one-step approach for the synthesis of α-(trifluoromethyl)-β-lactams and related products from fluorinated olefins, anilines and CO. Utilization of an advanced palladium catalyst system with the Ruphos ligand allows for selective cycloaminocarbonylations to give diverse fluorinated β-lactams in high yields.
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Affiliation(s)
- Yang Li
- Xi'an Key Laboratory of Textile Chemical Engineering Auxiliaries, School of Environmental and Chemical Engineering, Xi'an Polytechnic University No. 19 Jinhua South Road 710048 Xi'an China
- Leibniz-Institut für Katalyse e.V. RostockAlbert-Einstein-Straße 29a 18059 Rostock Germany
| | - Cai-Lin Zhang
- Xi'an Key Laboratory of Textile Chemical Engineering Auxiliaries, School of Environmental and Chemical Engineering, Xi'an Polytechnic University No. 19 Jinhua South Road 710048 Xi'an China
| | - Wei-Heng Huang
- Leibniz-Institut für Katalyse e.V. RostockAlbert-Einstein-Straße 29a 18059 Rostock Germany
| | - Ning Sun
- Xi'an Key Laboratory of Textile Chemical Engineering Auxiliaries, School of Environmental and Chemical Engineering, Xi'an Polytechnic University No. 19 Jinhua South Road 710048 Xi'an China
| | - Meng Hao
- Xi'an Key Laboratory of Textile Chemical Engineering Auxiliaries, School of Environmental and Chemical Engineering, Xi'an Polytechnic University No. 19 Jinhua South Road 710048 Xi'an China
| | - Helfried Neumann
- Leibniz-Institut für Katalyse e.V. RostockAlbert-Einstein-Straße 29a 18059 Rostock Germany
| | - Matthias Beller
- Leibniz-Institut für Katalyse e.V. RostockAlbert-Einstein-Straße 29a 18059 Rostock Germany
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10
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Abstract
Radical trifluoromethylation has been emerging as a versatile tool for the synthesis of trifluoromethylated compounds that play increasingly important roles in pharmaceuticals, agrochemicals and materials science.
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Affiliation(s)
- Haiwen Xiao
- School of Materials and Chemical Engineering, Ningbo University of Technology
- Ningbo 315211
- China
| | - Zhenzhen Zhang
- Key Laboratory of Organofluorine Chemistry
- Center for Excellence in Molecular Synthesis
- Shanghai Institute of Organic Chemistry
- Chinese Academy of Sciences
- Shanghai 200032
| | - Yewen Fang
- School of Materials and Chemical Engineering, Ningbo University of Technology
- Ningbo 315211
- China
| | - Lin Zhu
- Key Laboratory of Organofluorine Chemistry
- Center for Excellence in Molecular Synthesis
- Shanghai Institute of Organic Chemistry
- Chinese Academy of Sciences
- Shanghai 200032
| | - Chaozhong Li
- School of Materials and Chemical Engineering, Ningbo University of Technology
- Ningbo 315211
- China
- Key Laboratory of Organofluorine Chemistry
- Center for Excellence in Molecular Synthesis
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