1
|
Zhao Q, Etersque JM, Lu S, Telu S, Pike VW. On the Risk of 18F-Regioisomer Formation in the Copper-Free Radiofluorination of Aryliodonium Precursors. Org Lett 2023; 25:8650-8654. [PMID: 38012005 PMCID: PMC11327877 DOI: 10.1021/acs.orglett.3c03499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Aryliodonium precursors are widely applied for copper-free labeling of positron emission tomography (PET) tracers with fluorine-18. We assessed 18F-fluoroarene regioisomer formation in examples of these labeling methods. Aryliodonium ylides derived from Meldrum's acid bearing para electron-donating groups react with [18F]fluoride in acetonitrile to produce regioisomeric 18F-fluoroarenes via a competing aryne pathway. Regioisomer formation is decreased or absent in DMF. Analytically checking for the absence of the 18F-regioisomer from any particular PET tracer radiosynthesis using these or similar methods is recommended.
Collapse
Affiliation(s)
- Qunchao Zhao
- Molecular Imaging Branch, National Institute of Mental Health, Building 10, Room B3C346, 10 Center Drive, Bethesda, Maryland 20892, United States
| | - Jean M Etersque
- Molecular Imaging Branch, National Institute of Mental Health, Building 10, Room B3C346, 10 Center Drive, Bethesda, Maryland 20892, United States
| | - Shuiyu Lu
- Molecular Imaging Branch, National Institute of Mental Health, Building 10, Room B3C346, 10 Center Drive, Bethesda, Maryland 20892, United States
| | - Sanjay Telu
- Molecular Imaging Branch, National Institute of Mental Health, Building 10, Room B3C346, 10 Center Drive, Bethesda, Maryland 20892, United States
| | - Victor W Pike
- Molecular Imaging Branch, National Institute of Mental Health, Building 10, Room B3C346, 10 Center Drive, Bethesda, Maryland 20892, United States
| |
Collapse
|
2
|
Zhou YP, Wilks MQ, Dhaynaut M, Guehl NJ, Moon SH, Fakhri GE, Normandin MD, Brugarolas P. Radiosynthesis automation, non-human primate biodistribution and dosimetry of K + channel tracer [ 11 C]3MeO4AP. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.28.534386. [PMID: 37034655 PMCID: PMC10081174 DOI: 10.1101/2023.03.28.534386] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Purpose 4-Aminopyridine (4AP) is a medication for the symptomatic treatment of multiple sclerosis. Several 4AP-based PET tracers have been developed for imaging demyelination. In preclinical studies, [ 11 C]3MeO4AP has shown promise due to its high brain permeability, high metabolic stability, high plasma availability, and high in vivo binding affinity. To prepare for the translation to human studies, we developed a cGMP-compliant automated radiosynthesis protocol and evaluated the whole-body biodistribution and radiation dosimetry of [ 11 C]3MeO4AP in non-human primates (NHPs). Methods Automated radiosynthesis was carried out using a GE TRACERlab FX-C Pro synthesis module. One male and one female adult rhesus macaques were used in the study. A high-resolution CT from cranial vertex to knee was acquired. PET data were collected using a dynamic acquisition protocol with 4 bed positions and 13 passes over a total scan time of ∼150 minutes. Based on the CT and PET images, volumes of interest (VOIs) were manually drawn for selected organs. Non-decay corrected time-activity curves (TACs) were extracted for each VOI. Radiation dosimetry and effective dose were calculated from the integrated TACs using OLINDA software. Results Fully automated radiosynthesis of [ 11 C]3MeO4AP was achieved with 7.3 ± 1.2 % (n = 4) of non-decay corrected radiochemical yield within 38 min of synthesis and purification time. [ 11 C]3MeO4AP distributed quickly throughout the body and into the brain. The organs with highest dose were the kidneys. The average effective dose of [ 11 C]3MeO4AP was 4.27 ± 0.57 μSv/MBq. No significant changes in vital signs were observed during the scan. Conclusion The cGMP compliant automated radiosynthesis of [ 11 C]3MeO4AP was developed. The whole-body biodistribution and radiation dosimetry of [ 11 C]3MeO4AP was successfully evaluated in NHPs. [ 11 C]3MeO4AP shows lower average effective dose than [ 18 F]3F4AP and similar average effective dose as other carbon-11 tracers.
Collapse
|
3
|
Nerella SG, Singh P, Tulja S. Carbon-11 patents (2012-2022): synthetic methodologies and novel radiotracers for PET imaging. Expert Opin Ther Pat 2022; 32:817-831. [PMID: 35451896 DOI: 10.1080/13543776.2022.2070003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
INTRODUCTION Carbon-11 is a short-lived radionuclide with versatile applications in synthetic methodologies to develop a variety of novel PET radiotracers. Different primary and secondary carbon-11 precursors are generated from cyclotron produced [11C]CO2 and used to insert carbon-11 radionuclide into the target specific bioactive molecules. AREAS COVERED In this review, the patents as well as specific research articles on carbon-11 radiotracer synthesis and PET imaging applications in various diseases are mentioned since 2012 to 2022 through SciFinder database. EXPERT OPINION Carbon-11 is generally easier to insert into more organic scaffolds as a greater variety of functional groups. Despite the short half-life of carbon-11 radionuclide (t1/2 = 20.4 min), it is widely used in PET radiotracer development due to its direct insertion into bioactive compounds and less isotopic dilution unlike other positron emitters like fluorine-18. Various synthons can be easily generated using the primary and secondary carbon-11 precursors like [11C]CO2, [11C]CH4, 11CH3I, 11CO, 11COCl2, 11CN, 11CS2, and 11CH3OTf etc. that would be useful to develop any PET radiotracers by adapting various organic methods. The carbon-11 radiotracers provide target-oriented information associated with the pharmacology, and physiological conditions of the disease status. Various protocols and automated methods were adapted for easy and convenient synthesis of carbon-11 radiotracers. The PET advances drug development and clinical trials by revealing biological target engagement, proof of mechanism, pharmacokinetic, and pharmacodynamic profiles of new drug candidates using selective radiotracers.
Collapse
Affiliation(s)
- Sridhar Goud Nerella
- Department of Neuroimaging and Interventional Radiology (NI & IR), National Institute of Mental Health and Neurosciences (NIMHANS), Bengaluru-560 029, India.,Current address; Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda-20892, USA
| | - Priti Singh
- Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research (NIPER), Hyderabad-500 037, India
| | - Sanam Tulja
- Department of Microbiology and Applied Sciences, University of Agricultural Sciences, Bangalore-560 065, India
| |
Collapse
|
4
|
Belen’kii LI, Gazieva GA, Evdokimenkova YB, Soboleva NO. The literature of heterocyclic chemistry, Part XX, 2020. ADVANCES IN HETEROCYCLIC CHEMISTRY 2022. [DOI: 10.1016/bs.aihch.2022.10.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
|
5
|
Zhou YP, Makaravage KJ, Brugarolas P. Radiolabeling with [ 11C]HCN for Positron emission tomography. Nucl Med Biol 2021; 102-103:56-86. [PMID: 34624831 PMCID: PMC8978408 DOI: 10.1016/j.nucmedbio.2021.09.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 08/20/2021] [Accepted: 09/20/2021] [Indexed: 12/22/2022]
Abstract
Hydrogen cyanide (HCN) is a versatile synthon for generating carbon‑carbon and carbon-heteroatom bonds. Unlike other one-carbon synthons (i.e., CO, CO2), HCN can function as a nucleophile (as in potassium cyanide, KCN) and an electrophile (as in cyanogen bromide, (CN)Br). The incorporation of the CN motif into organic molecules generates nitriles, hydantoins and (thio)cyanates, which can be converted to carboxylic acids, aldehydes, amides and amines. Such versatile chemistry is particularly attractive in PET radiochemistry where diverse bioactive small molecules incorporating carbon-11 in different positions need to be produced. The first examples of making [11C]HCN for radiolabeling date back to the 1960s. During the ensuing decades, [11C]cyanide labeling was popular for producing biologically important molecules including 11C-labeled α-amino acids, sugars and neurotransmitters. [11C]cyanation is now reemerging in many PET centers due to its versatility for making novel tracers. Here, we summarize the chemistry of [11C]HCN, review the methods to make [11C]HCN past and present, describe methods for labeling different types of molecules with [11C]HCN, and provide an overview of the reactions available to convert nitriles into other functional groups. Finally, we discuss some of the challenges and opportunities in [11C]HCN labeling such as developing more robust methods to produce [11C]HCN and developing rapid and selective methods to convert nitriles into other functional groups in complex molecules.
Collapse
Affiliation(s)
- Yu-Peng Zhou
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States
| | - Katarina J Makaravage
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States
| | - Pedro Brugarolas
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States.
| |
Collapse
|
6
|
Jakobsson JE, Telu S, Lu S, Jana S, Pike VW. Broad Scope and High-Yield Access to Unsymmetrical Acyclic [ 11 C]Ureas for Biomedical Imaging from [ 11 C]Carbonyl Difluoride. Chemistry 2021; 27:10369-10376. [PMID: 33890705 PMCID: PMC10134011 DOI: 10.1002/chem.202100690] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Indexed: 12/13/2022]
Abstract
Effective methods are needed for labelling acyclic ureas with carbon-11 (t1/2 =20.4 min) as potential radiotracers for biomedical imaging with positron emission tomography (PET). Herein, we describe the rapid and high-yield syntheses of unsymmetrical acyclic [11 C]ureas under mild conditions (room temperature and within 7 min) using no-carrier-added [11 C]carbonyl difluoride with aliphatic and aryl amines. This methodology is compatible with diverse functionality (e. g., hydroxy, carboxyl, amino, amido, or pyridyl) in the substrate amines. The labelling process proceeds through putative [11 C]carbamoyl fluorides and for primary amines through isolable [11 C]isocyanate intermediates. Unsymmetrical [11 C]ureas are produced with negligible amounts of unwanted symmetrical [11 C]urea byproducts. Moreover, the overall labelling method tolerates trace water and the generally moderate to excellent yields show good reproducibility. [11 C]Carbonyl difluoride shows exceptional promise for application to the synthesis of acyclic [11 C]ureas as new radiotracers for biomedical imaging with PET.
Collapse
Affiliation(s)
- Jimmy E Jakobsson
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, 10 Center Drive, Bethesda, MD, 20892-1003, USA
| | - Sanjay Telu
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, 10 Center Drive, Bethesda, MD, 20892-1003, USA
| | - Shuiyu Lu
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, 10 Center Drive, Bethesda, MD, 20892-1003, USA
| | - Susovan Jana
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, 10 Center Drive, Bethesda, MD, 20892-1003, USA
| | - Victor W Pike
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, 10 Center Drive, Bethesda, MD, 20892-1003, USA
| |
Collapse
|
7
|
Ramos-Torres KM, Zhou YP, Yang BY, Guehl NJ, Sung-Hyun M, Telu S, Normandin MD, Pike VW, Brugarolas P. Syntheses of [ 11C]2- and [ 11C]3-trifluoromethyl-4-aminopyridine: potential PET radioligands for demyelinating diseases. RSC Med Chem 2020; 11:1161-1167. [PMID: 33479620 PMCID: PMC7651860 DOI: 10.1039/d0md00190b] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 07/17/2020] [Indexed: 11/21/2022] Open
Abstract
Trifluoromethyl groups are of great interest in PET radiopharmaceuticals. Radiolabelled 4-aminopyridine (4AP) derivatives have been proposed for imaging demyelinating diseases. Here, we describe methods for producing 11C-trifluoromethylated derivatives of 4AP and present early imaging results with [11C]3-trifluoromethyl-4AP in a rhesus macaque. This study shows the utility of [11C]CuCF3 for labelling pyridines and provides initial evidence for the potential use of [11C]3-trifluoromethyl-4AP as a PET radioligand.
Collapse
Affiliation(s)
- Karla M Ramos-Torres
- Gordon Center for Medical Imaging , Department of Radiology , Massachusetts General Hospital and Harvard Medical School , Boston , MA , USA .
| | - Yu-Peng Zhou
- Gordon Center for Medical Imaging , Department of Radiology , Massachusetts General Hospital and Harvard Medical School , Boston , MA , USA .
| | - Bo Yeun Yang
- Molecular Imaging Branch , National Institute of Mental Health , National Institutes of Health , Bethesda , MD , USA .
| | - Nicolas J Guehl
- Gordon Center for Medical Imaging , Department of Radiology , Massachusetts General Hospital and Harvard Medical School , Boston , MA , USA .
| | - Moon Sung-Hyun
- Gordon Center for Medical Imaging , Department of Radiology , Massachusetts General Hospital and Harvard Medical School , Boston , MA , USA .
| | - Sanjay Telu
- Molecular Imaging Branch , National Institute of Mental Health , National Institutes of Health , Bethesda , MD , USA .
| | - Marc D Normandin
- Gordon Center for Medical Imaging , Department of Radiology , Massachusetts General Hospital and Harvard Medical School , Boston , MA , USA .
| | - Victor W Pike
- Molecular Imaging Branch , National Institute of Mental Health , National Institutes of Health , Bethesda , MD , USA .
| | - Pedro Brugarolas
- Gordon Center for Medical Imaging , Department of Radiology , Massachusetts General Hospital and Harvard Medical School , Boston , MA , USA .
| |
Collapse
|