PET and SPECT Tracer Development via Copper-Mediated Radiohalogenation of Divergent and Stable Aryl-Boronic Esters

<b>Background/Objectives</b>: Positron emission tomography (PET) and single-photon emission computed tomography (SPECT) are highly sensitive clinical imaging modalities, frequently employed in conjunction with magnetic resonance imaging (MRI) or computed tomography (CT) for diagnosing a...

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Main Authors: Austin Craig, Frederik J. Sachse, Markus Laube, Florian Brandt, Klaus Kopka, Sven Stadlbauer
Format: Article
Language:English
Published: MDPI AG 2025-06-01
Series:Pharmaceutics
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Online Access:https://www.mdpi.com/1999-4923/17/7/837
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author Austin Craig
Frederik J. Sachse
Markus Laube
Florian Brandt
Klaus Kopka
Sven Stadlbauer
author_facet Austin Craig
Frederik J. Sachse
Markus Laube
Florian Brandt
Klaus Kopka
Sven Stadlbauer
author_sort Austin Craig
collection DOAJ
description <b>Background/Objectives</b>: Positron emission tomography (PET) and single-photon emission computed tomography (SPECT) are highly sensitive clinical imaging modalities, frequently employed in conjunction with magnetic resonance imaging (MRI) or computed tomography (CT) for diagnosing a wide range of disorders. Efficient and robust radiolabeling methods are needed to accommodate the increasing demand for PET and SPECT tracer development. Copper-mediated radiohalogenation (CMRH) reactions enable rapid late-stage preparation of radiolabeled arenes, yet synthetic challenges and radiolabeling precursors’ instability can limit the applications of CMRH approaches. <b>Methods</b>: A series of aryl-boronic acids were converted into their corresponding aryl-boronic acid 1,1,2,2-tetraethylethylene glycol esters [ArB(Epin)s] and aryl-boronic acid 1,1,2,2-tetrapropylethylene glycol esters [ArB(Ppin)s] as stable and versatile precursor building blocks for radiolabeling via CMRH. General protocols for the preparation of <sup>18</sup>F-labeled and <sup>123</sup>I-labeled arenes utilizing CMRH of these substrates were developed and applied. The radiochemical conversions (RCC) were determined by radio-(U)HPLC. <b>Results</b>: Both ArB(Epin)s and ArB(Ppin)s-based radiolabeling precursors were prepared in a one-step synthesis with chemical yields of 49–99%. Radiolabeling of the aryl-boronic esters with fluorine-18 or iodine-123 via CMRH furnished the corresponding radiolabeled arenes with RCC of 7–99% and 10–99%, respectively. Notably, a radiohalogenated prosthetic group containing a vinyl sulfone motif was obtained with an activity yield (AY) of 18 ± 3%, and applied towards the preparation of two clinically relevant PET tracers. <b>Conclusions</b>: This approach enables the synthesis of stable radiolabeling precursors and thus provides increased versatility in the application of CMRH, thereby supporting the development of novel PET and SPECT radiotracers.
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spelling doaj-art-74c93a2e478e4593bcc6d3766f43a3c22025-08-20T03:32:27ZengMDPI AGPharmaceutics1999-49232025-06-0117783710.3390/pharmaceutics17070837PET and SPECT Tracer Development via Copper-Mediated Radiohalogenation of Divergent and Stable Aryl-Boronic EstersAustin Craig0Frederik J. Sachse1Markus Laube2Florian Brandt3Klaus Kopka4Sven Stadlbauer5Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstraße 400, D-01328 Dresden, GermanyInstitute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstraße 400, D-01328 Dresden, GermanyInstitute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstraße 400, D-01328 Dresden, GermanyUniversitätsklinikum Carl Gustav Carus Dresden, Fetscherstraße 74, D-01307 Dresden, GermanyInstitute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstraße 400, D-01328 Dresden, GermanyInstitute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstraße 400, D-01328 Dresden, Germany<b>Background/Objectives</b>: Positron emission tomography (PET) and single-photon emission computed tomography (SPECT) are highly sensitive clinical imaging modalities, frequently employed in conjunction with magnetic resonance imaging (MRI) or computed tomography (CT) for diagnosing a wide range of disorders. Efficient and robust radiolabeling methods are needed to accommodate the increasing demand for PET and SPECT tracer development. Copper-mediated radiohalogenation (CMRH) reactions enable rapid late-stage preparation of radiolabeled arenes, yet synthetic challenges and radiolabeling precursors’ instability can limit the applications of CMRH approaches. <b>Methods</b>: A series of aryl-boronic acids were converted into their corresponding aryl-boronic acid 1,1,2,2-tetraethylethylene glycol esters [ArB(Epin)s] and aryl-boronic acid 1,1,2,2-tetrapropylethylene glycol esters [ArB(Ppin)s] as stable and versatile precursor building blocks for radiolabeling via CMRH. General protocols for the preparation of <sup>18</sup>F-labeled and <sup>123</sup>I-labeled arenes utilizing CMRH of these substrates were developed and applied. The radiochemical conversions (RCC) were determined by radio-(U)HPLC. <b>Results</b>: Both ArB(Epin)s and ArB(Ppin)s-based radiolabeling precursors were prepared in a one-step synthesis with chemical yields of 49–99%. Radiolabeling of the aryl-boronic esters with fluorine-18 or iodine-123 via CMRH furnished the corresponding radiolabeled arenes with RCC of 7–99% and 10–99%, respectively. Notably, a radiohalogenated prosthetic group containing a vinyl sulfone motif was obtained with an activity yield (AY) of 18 ± 3%, and applied towards the preparation of two clinically relevant PET tracers. <b>Conclusions</b>: This approach enables the synthesis of stable radiolabeling precursors and thus provides increased versatility in the application of CMRH, thereby supporting the development of novel PET and SPECT radiotracers.https://www.mdpi.com/1999-4923/17/7/837copper-mediated radiohalogenation (CMRH)<sup>18</sup>F-fluorination<sup>123</sup>I-iodinationpositron emission tomography (PET)radiohalogenationsingle-photon emission computed tomography (SPECT)
spellingShingle Austin Craig
Frederik J. Sachse
Markus Laube
Florian Brandt
Klaus Kopka
Sven Stadlbauer
PET and SPECT Tracer Development via Copper-Mediated Radiohalogenation of Divergent and Stable Aryl-Boronic Esters
Pharmaceutics
copper-mediated radiohalogenation (CMRH)
<sup>18</sup>F-fluorination
<sup>123</sup>I-iodination
positron emission tomography (PET)
radiohalogenation
single-photon emission computed tomography (SPECT)
title PET and SPECT Tracer Development via Copper-Mediated Radiohalogenation of Divergent and Stable Aryl-Boronic Esters
title_full PET and SPECT Tracer Development via Copper-Mediated Radiohalogenation of Divergent and Stable Aryl-Boronic Esters
title_fullStr PET and SPECT Tracer Development via Copper-Mediated Radiohalogenation of Divergent and Stable Aryl-Boronic Esters
title_full_unstemmed PET and SPECT Tracer Development via Copper-Mediated Radiohalogenation of Divergent and Stable Aryl-Boronic Esters
title_short PET and SPECT Tracer Development via Copper-Mediated Radiohalogenation of Divergent and Stable Aryl-Boronic Esters
title_sort pet and spect tracer development via copper mediated radiohalogenation of divergent and stable aryl boronic esters
topic copper-mediated radiohalogenation (CMRH)
<sup>18</sup>F-fluorination
<sup>123</sup>I-iodination
positron emission tomography (PET)
radiohalogenation
single-photon emission computed tomography (SPECT)
url https://www.mdpi.com/1999-4923/17/7/837
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