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Fragment-based labeling using condensation reactions of six potential 5-HT7R PET tracers. J Radioanal Nucl Chem 2020. [DOI: 10.1007/s10967-020-07475-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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2
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Performing radiosynthesis in microvolumes to maximize molar activity of tracers for positron emission tomography. Commun Chem 2018; 1. [PMID: 34291178 DOI: 10.1038/s42004-018-0009-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Positron emission tomography (PET) is a molecular diagnostic imaging technology to quantitatively visualize biological processes in vivo. For many applications, including imaging of low tissue density targets (e.g. neuroreceptors), imaging in small animals, and evaluation of novel tracers, the injected PET tracer must be produced with high molar activity to ensure low occupancy of biological targets and avoid pharmacologic effects. Additionally, high molar activity is essential for tracers with lengthy syntheses or tracers transported to distant imaging sites. We show that radiosynthesis of PET tracers in microliter volumes instead of conventional milliliter volumes results in substantially increased molar activity, and we identify the most relevant variables affecting this parameter. Furthermore, using the PET tracer [18F]fallypride, we illustrate that molar activity can have a significant impact on biodistribution. With full automation, microdroplet platforms could provide a means for radiochemists to routinely, conveniently, and safely produce PET tracers with high molar activity.
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Production of diverse PET probes with limited resources: 24 18F-labeled compounds prepared with a single radiosynthesizer. Proc Natl Acad Sci U S A 2017; 114:11309-11314. [PMID: 29073049 DOI: 10.1073/pnas.1710466114] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
New radiolabeled probes for positron-emission tomography (PET) are providing an ever-increasing ability to answer diverse research and clinical questions and to facilitate the discovery, development, and clinical use of drugs in patient care. Despite the high equipment and facility costs to produce PET probes, many radiopharmacies and radiochemistry laboratories use a dedicated radiosynthesizer to produce each probe, even if the equipment is idle much of the time, to avoid the challenges of reconfiguring the system fluidics to switch from one probe to another. To meet growing demand, more cost-efficient approaches are being developed, such as radiosynthesizers based on disposable "cassettes," that do not require reconfiguration to switch among probes. However, most cassette-based systems make sacrifices in synthesis complexity or tolerated reaction conditions, and some do not support custom programming, thereby limiting their generality. In contrast, the design of the ELIXYS FLEX/CHEM cassette-based synthesizer supports higher temperatures and pressures than other systems while also facilitating flexible synthesis development. In this paper, the syntheses of 24 known PET probes are adapted to this system to explore the possibility of using a single radiosynthesizer and hot cell for production of a diverse array of compounds with wide-ranging synthesis requirements, alongside synthesis development efforts. Most probes were produced with yields and synthesis times comparable to literature reports, and because hardware modification was unnecessary, it was convenient to frequently switch among probes based on demand. Although our facility supplies probes for preclinical imaging, the same workflow would be applicable in a clinical setting.
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Kügler F, Ermert J, Kaufholz P, Coenen HH. 4-[18F]Fluorophenylpiperazines by improved Hartwig-Buchwald N-arylation of 4-[18F]fluoroiodobenzene, formed via hypervalent λ3-iodane precursors: application to build-up of the dopamine D4 ligand [18F]FAUC 316. Molecules 2014; 20:470-86. [PMID: 25558857 PMCID: PMC6272738 DOI: 10.3390/molecules20010470] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Accepted: 12/18/2014] [Indexed: 12/24/2022] Open
Abstract
Substituted phenylpiperazines are often neuropharmacologically active compounds and in many cases are essential pharmacophores of neuroligands for different receptors such as D2-like dopaminergic, serotoninergic and other receptors. Nucleophilic, no-carrier-added (n.c.a.) 18F-labelling of these ligands in an aromatic position is desirable for studying receptors with in vivo molecular imaging. 1-(4-[18F]Fluorophenyl)piperazine was synthesized in two reaction steps starting by 18F-labelling of a iodobenzene-iodonium precursor, followed by Pd-catalyzed N-arylation of the intermediate 4-[18F]fluoro-iodobenzene. Different palladium catalysts and solvents were tested with particular attention to the polar solvents dimethylformamide (DMF) and dimethylsulfoxide (DMSO). Weak inorganic bases like potassium phosphate or cesium carbonate seem to be essential for the arylation step and lead to conversation rates above 70% in DMF which is comparable to those in typically used toluene. In DMSO even quantitative conversation was observed. Overall radiochemical yields of up to 40% and 60% in DMF and DMSO, respectively, were reached depending on the labelling yield of the first step. The fluorophenylpiperazine obtained was coupled in a third reaction step with 2-formyl-1H-indole-5-carbonitrile to yield the highly selective dopamine D4 ligand [18F]FAUC 316.
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Affiliation(s)
- Fabian Kügler
- Institute of Neuroscience and Medicine, INM-5: Nuclear Chemistry, Forschungszentrum Jülich, 52425 Jülich, Germany.
| | - Johannes Ermert
- Institute of Neuroscience and Medicine, INM-5: Nuclear Chemistry, Forschungszentrum Jülich, 52425 Jülich, Germany.
| | - Peter Kaufholz
- Institute of Neuroscience and Medicine, INM-5: Nuclear Chemistry, Forschungszentrum Jülich, 52425 Jülich, Germany.
| | - Heinz H Coenen
- Institute of Neuroscience and Medicine, INM-5: Nuclear Chemistry, Forschungszentrum Jülich, 52425 Jülich, Germany.
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5
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Plug-and-play modules for flexible radiosynthesis. Appl Radiat Isot 2013; 78:113-24. [PMID: 23702795 DOI: 10.1016/j.apradiso.2013.04.023] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2012] [Revised: 03/23/2013] [Accepted: 04/13/2013] [Indexed: 11/23/2022]
Abstract
We present a plug-and-play radiosynthesis platform and accompanying computer software based on modular subunits that can easily and flexibly be configured to implement a diverse range of radiosynthesis protocols. Modules were developed that perform: (i) reagent storage and delivery, (ii) evaporations and sealed reactions, and (iii) cartridge-based purifications. The reaction module incorporates a simple robotic mechanism that removes tubing from the vessel and replaces it with a stopper prior to sealed reactions, enabling the system to withstand high pressures and thus provide tremendous flexibility in choice of solvents and temperatures. Any number of modules can rapidly be connected together using only a few fluidic connections to implement a particular synthesis, and the resulting system is controlled in a semi-automated fashion by a single software interface. Radiosyntheses of 2-[(18)F]fluoro-2-deoxy-d-glucose ([(18)F]FDG), 1-[(18)F]fluoro-4-nitrobenzene ([(18)F]FNB), and 2'-deoxy-2'-[(18)F]fluoro-1-β-d-arabinofuranosyl cytosine (d-[(18)F]FAC) were performed to validate the system and demonstrate its versatility.
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Gao R, Canney DJ. A versatile and practical microwave-assisted synthesis of sterically hindered N-arylpiperazines. J Org Chem 2011; 75:7451-3. [PMID: 20863109 DOI: 10.1021/jo101478c] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A wide-ranging and practical synthesis of structurally diverse, sterically hindered N-arylpiperazines from 2,2'-(4-nitrophenylsulfonylazanediyl) bis(ethane-2,1-diyl) bis(4-nitrobenzenesulfonate) and substituted anilines has been achieved using microwave irradiation in acetonitrile followed by deprotection with PhSH.
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Affiliation(s)
- Rong Gao
- Temple University School of Pharmacy, Department of Pharmaceutical Sciences, 3307 North Broad Street, Philadelphia, Pennsylvania 19140, USA
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Pretze M, Große-Gehling P, Mamat C. Cross-coupling reactions as valuable tool for the preparation of PET radiotracers. Molecules 2011; 16:1129-65. [PMID: 21270732 PMCID: PMC6259626 DOI: 10.3390/molecules16021129] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2010] [Revised: 01/17/2011] [Accepted: 01/21/2011] [Indexed: 11/16/2022] Open
Abstract
The increasing application of positron emission tomography (PET) in nuclear medicine has stimulated the extensive development of a multitude of new radiotracers and novel radiolabeling procedures with the most prominent short-lived positron emitters carbon-11 and fluorine-18. Radiolabeling with these radionuclides represents a remarkable challenge. Special attention has to be paid to synthesis time and specific labeling techniques due to the short physical half life of the respective radionuclides 11C (t1/2 = 20.4 min) and 18F (t1/2 = 109.8 min). In the past, numerous transition metal-catalyzed reactions were employed in organic chemistry, even though only a handful of these coupling reactions were adopted in radiochemical practice. Thus, the implementation of modern synthesis methods like cross-coupling reactions offers the possibility to develop a wide variety of novel radiotracers. The introduction of catalysts based on transition metal complexes bears a high potential for rapid, efficient, highly selective and functional group-tolerating incorporation of carbon-11 and fluorine-18 into target molecules. This review deals with design, application and improvement of transition metal-mediated carbon-carbon as well as carbon-heteroatom cross-coupling reactions as a labeling feature with the focus on the preparation of radiolabeled compounds for molecular imaging.
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Affiliation(s)
- Marc Pretze
- Institut für Radiopharmazie, Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstraße 400, D-01328 Dresden, Germany
| | - Philipp Große-Gehling
- OncoRay – National Center for Radiation Research in Oncology, Medical Faculty Carl Gustav Carus, Dresden University of Technology, Fetscherstraße 74, P.O. Box 41, D-01307 Dresden, Germany
| | - Constantin Mamat
- Institut für Radiopharmazie, Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstraße 400, D-01328 Dresden, Germany
- Author to whom correspondence should be addressed; ; Tel.: +49-351-260 2805; Fax: +49-351-260 3232
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8
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Affiliation(s)
- Lisheng Cai
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Rm. B3 C346, 10 Center Drive, Bethesda, MD 20892‐1003, USA, Fax: +1‐301‐480‐5112
| | - Shuiyu Lu
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Rm. B3 C346, 10 Center Drive, Bethesda, MD 20892‐1003, USA, Fax: +1‐301‐480‐5112
| | - Victor W. Pike
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Rm. B3 C346, 10 Center Drive, Bethesda, MD 20892‐1003, USA, Fax: +1‐301‐480‐5112
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Coenen HH. Fluorine-18 labeling methods: Features and possibilities of basic reactions. ERNST SCHERING RESEARCH FOUNDATION WORKSHOP 2007:15-50. [PMID: 17172151 DOI: 10.1007/978-3-540-49527-7_2] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Many experimental and established tracers make fluorine- 18 the most widely used radionuclide in positron emission tomography with an increasing demand for new or simpler 18F-labeling procedures. After a brief summary of the advantages of the nuclide and its major production routes, the basic features of the principal radiofluorination methods are described. These comprise direct electrophilic and nucleophilic processes, or in case of more complex molecules, the labeling of synthons and prosthetic groups for indirect built-up syntheses. While addressing the progress of no-carrier-added 18F-labeling procedures, the following chapters on more specific topics in this book are introduced. Emphasis is given to radiofluorination of arenes--especially with iodonium leaving groups. Examples of radiopharmaceutical syntheses are mentioned in order to illustrate strategic concepts of labeling with fluorine-18.
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Affiliation(s)
- H H Coenen
- Institut für Nuklearchemie, Forschungszentrum Jülich GmbH, Germany.
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10
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Olma S, Ermert J, Coenen HH. 4-[18F]fluorophenyl ureas via carbamate-4-nitrophenyl esters and 4-[18F]fluoroaniline. J Labelled Comp Radiopharm 2006. [DOI: 10.1002/jlcr.1121] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Duvelleroy D, Perrio C, Parisel O, Lasne MC. Rapid synthesis of quinoline-4-carboxylic acid derivatives from arylimines and 2-substituted acrylates or acrylamides under indium(iii) chloride and microwave activations. Scope and limitations of the reaction. Org Biomol Chem 2005; 3:3794-804. [PMID: 16211116 DOI: 10.1039/b509400c] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Rapid synthesis of quinoline-4-carboxylic acid derivatives has been achieved by reaction of 2-methoxy acrylates or acrylamides with N-arylbenzaldimines in acetonitrile under InCl3 catalysis and microwave irradiation. Isolated yields up to 57% within 3 min have been obtained. The Lewis acid and the microwave activation appeared as crucial parameters for the reaction. The role of indium chloride and ytterbium triflate was specified using 13C NMR data and model theoretical studies.
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Affiliation(s)
- Dorothée Duvelleroy
- Laboratoire de Chimie Moléculaire et Thioorganique, UMR 6507 CNRS-ENSICAEN, Université de Caen-Basse Normandie, 6 Boulevard du Maréchal Juin, 14050 Caen Cedex, France
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Lasne MC, Perrio C, Rouden J, Barré L, Roeda D, Dolle F, Crouzel C. Chemistry of β +-Emitting Compounds Based on Fluorine-18. Top Curr Chem (Cham) 2002. [DOI: 10.1007/3-540-46009-8_7] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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13
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Mishani E, Cristel ME, Dence CS, McCarthy TJ, Welch MJ. Application of a novel phenylpiperazine formation reaction to the radiosynthesis of a model fluorine-18-labeled radiopharmaceutical (18FTFMPP). Nucl Med Biol 1997; 24:269-73. [PMID: 9228662 DOI: 10.1016/s0969-8051(97)00063-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The labeled serotonin agonist 3-[18F]fluoro-N-(alpha,alpha,alpha-trifluoro-m-tolyl)piperazine (18FTFMPP) was prepared rapidly using the labeling procedure for trifluorotoluenes, [18F]fluoro-for-nitro exchange, followed by an alumina-supported bis-alkylation. After normal-phase HPLC purification, the labeled product was obtained in 20-32% (n = 20) decay-corrected radiochemical yield with a radiochemical purity > 98% and a specific activity of 100 GBq/mumol. The synthesis time including purification was 3 h. The receptor binding affinity of FTFMPP to rat brain membranes was found to be similar to that of the nonfluorinated parent compound (TFMPP). Although TFMPP has been proposed by others as an agent for the imaging of serotonin receptors, only minimal receptor-mediated uptake was observed.
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Affiliation(s)
- E Mishani
- Mallinckrodt Institute of Radiology, Washington University, Saint Louis, MO 63110, USA
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Ashworth S, Hume SP, Lammertsma AA, Opacka-Juffry J, Shah F, Pike VW. Development of central 5-HT2A receptor radioligands for PET: comparison of [3H]RP 62203 and [3H]SR 46349B kinetics in rat brain. Nucl Med Biol 1996; 23:245-50. [PMID: 8782232 DOI: 10.1016/0969-8051(95)02053-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
[3H]RP 62203 and [3H]SR 46349B binding were assessed in rat brain after intravenous (iv) injection. The distribution of specific binding of each radioligand corresponded to the known distribution of 5-HT2A receptor sites. The maximum signals (counts/g tissue over counts/g cerebellum) given by [3H]RP 62203 and [3H]SR 46349B were 9.0 +/- 0.9 at 60 min and 3.2 +/- 0.3 at 30 min, respectively, in frontopolar cortex. Specific binding was quantified using a reference-tissue compartment model. RP 62203 appears to be more suitable than SR 46349B for development as a PET radioligand on the basis of its higher receptor specific signal.
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Affiliation(s)
- S Ashworth
- Cyclotron Unit, Royal Postgraduate Medical School, Hammersmith Hospital, London, UK
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Preparation of [18F]RP 62203, a selective ligand for the study of serotonin receptors (5-HT2) by rapid “in situ” piperazine formation. Appl Radiat Isot 1994. [DOI: 10.1016/0969-8043(94)90188-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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