1
|
Jewett EM, Någren K, Mock BH, Watkins GL. 30 years of [ 11C]methyl triflate. Appl Radiat Isot 2023; 197:110812. [PMID: 37087867 DOI: 10.1016/j.apradiso.2023.110812] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 03/21/2023] [Accepted: 04/09/2023] [Indexed: 04/25/2023]
Abstract
Some scientific discoveries are well known only to a core group of researchers working on technical subjects. Nevertheless, they open new research directions, allow existing knowledge to be viewed in entirely new and useful ways, or provide a way to make something that was hard or impossible to make before. Carbon-11 methyl triflate ([11C]MeOTf) is one such advance, facilitating the synthesis of many carbon-11 radio tracers and broadening the range of applications of carbon-11 radiochemistry. The year 2022 marked the 30th anniversary of the original paper in Applied Radiation and Isotopes introducing a simple synthesis of [11C]MeOTf from carbon-11 methyl iodide ([11C]MeI) and it also marked the end of the fruitful career and life of the researcher who developed it, Douglas Jewett. It seems fitting to say a few words on how it came to be and how it has helped advance carbon-11 radiochemistry.
Collapse
Affiliation(s)
| | - Kjell Någren
- Östre Stationsvej, 36 1TH, 5000, Odense, Denmark
| | - Bruce H Mock
- Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | | |
Collapse
|
2
|
Shi L, Yu G, Zhao L, Wen Z, Li Y, Kan B, Jian X. Methemoglobinemia and Delayed Encephalopathy After 5-Bromo-2-Nitropyridine Poisoning: A Rare Case Report. Front Public Health 2022; 10:942003. [PMID: 35875039 PMCID: PMC9300930 DOI: 10.3389/fpubh.2022.942003] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 06/21/2022] [Indexed: 11/21/2022] Open
Abstract
5-bromo-2-nitropyridine, an intermediate in the synthesis of pharmaceutical and pesticide products, is toxic to the human body. However, 5-bromo-2-nitropyridine poisoning has not been previously reported. Here, we report the case of a 40-year-old man who suffered skin and respiratory tract exposure to leaked 5-Bromo-2-nitropyridine at work. After exposure, the patient rapidly developed dizziness, fatigue, nausea, vomiting, chest distress, diffuse cyanosis, and coma. Methemoglobinemia, hemolytic anemia, rhabdomyolysis, and acute renal failure were observed after admission. He improved markedly after treatment, but delayed encephalopathy was confirmed 82 days after the exposure. This case highlights that 5-bromo-2-nitropyridine can be absorbed through the skin and respiratory tract, resulting in methemoglobinemia and delayed encephalopathy.
Collapse
Affiliation(s)
- Longke Shi
- School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, China
- Department of Poisoning and Occupational Diseases, Emergency Medicine, Qilu Hospital of Shandong University, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Guangcai Yu
- School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Liwen Zhao
- School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, China
- Department of Poisoning and Occupational Diseases, Emergency Medicine, Qilu Hospital of Shandong University, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Zixin Wen
- School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, China
- School of Nursing and Rehabilitation, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Yaqian Li
- School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Baotian Kan
- School of Nursing and Rehabilitation, Cheeloo College of Medicine, Shandong University, Jinan, China
- Department of Geriatric Medicine, Qilu Hospital of Shandong University, Cheeloo College of Medicine, Shandong University, Jinan, China
- Baotian Kan
| | - Xiangdong Jian
- School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, China
- Department of Poisoning and Occupational Diseases, Emergency Medicine, Qilu Hospital of Shandong University, Cheeloo College of Medicine, Shandong University, Jinan, China
- *Correspondence: Xiangdong Jian
| |
Collapse
|
3
|
Yousefzadeh-Nowshahr E, Winter G, Bohn P, Kneer K, von Arnim CAF, Otto M, Solbach C, Anderl-Straub S, Polivka D, Fissler P, Strobel J, Kletting P, Riepe MW, Higuchi M, Glatting G, Ludolph A, Beer AJ. Quantitative analysis of regional distribution of tau pathology with 11C-PBB3-PET in a clinical setting. PLoS One 2022; 17:e0266906. [PMID: 35404966 PMCID: PMC9045369 DOI: 10.1371/journal.pone.0266906] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Accepted: 03/29/2022] [Indexed: 12/28/2022] Open
Abstract
PURPOSE The recent developments of tau-positron emission tomography (tau-PET) enable in vivo assessment of neuropathological tau aggregates. Among the tau-specific tracers, the application of 11C-pyridinyl-butadienyl-benzothiazole 3 (11C-PBB3) in PET shows high sensitivity to Alzheimer disease (AD)-related tau deposition. The current study investigates the regional tau load in patients within the AD continuum, biomarker-negative individuals (BN) and patients with suspected non-AD pathophysiology (SNAP) using 11C-PBB3-PET. MATERIALS AND METHODS A total of 23 memory clinic outpatients with recent decline of episodic memory were examined using 11C-PBB3-PET. Pittsburg compound B (11C-PIB) PET was available for 17, 18F-flurodeoxyglucose (18F-FDG) PET for 16, and cerebrospinal fluid (CSF) protein levels for 11 patients. CSF biomarkers were considered abnormal based on Aβ42 (< 600 ng/L) and t-tau (> 450 ng/L). The PET biomarkers were classified as positive or negative using statistical parametric mapping (SPM) analysis and visual assessment. Using the amyloid/tau/neurodegeneration (A/T/N) scheme, patients were grouped as within the AD continuum, SNAP, and BN based on amyloid and neurodegeneration status. The 11C-PBB3 load detected by PET was compared among the groups using both atlas-based and voxel-wise analyses. RESULTS Seven patients were identified as within the AD continuum, 10 SNAP and 6 BN. In voxel-wise analysis, significantly higher 11C-PBB3 binding was observed in the AD continuum group compared to the BN patients in the cingulate gyrus, tempo-parieto-occipital junction and frontal lobe. Compared to the SNAP group, patients within the AD continuum had a considerably increased 11C-PBB3 uptake in the posterior cingulate cortex. There was no significant difference between SNAP and BN groups. The atlas-based analysis supported the outcome of the voxel-wise quantification analysis. CONCLUSION Our results suggest that 11C-PBB3-PET can effectively analyze regional tau load and has the potential to differentiate patients in the AD continuum group from the BN and SNAP group.
Collapse
Affiliation(s)
- Elham Yousefzadeh-Nowshahr
- Department of Nuclear Medicine, Medical Radiation Physics, Ulm
University, Ulm, Germany
- Department of Nuclear Medicine, Medical Center—University of Freiburg,
Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Gordon Winter
- Department of Nuclear Medicine, Ulm University, Ulm,
Germany
| | - Peter Bohn
- Department of Nuclear Medicine, Inselspital Bern—University of Bern,
Bern, Switzerland
| | - Katharina Kneer
- Department of Nuclear Medicine, Ulm University, Ulm,
Germany
| | - Christine A. F. von Arnim
- Department of Neurology, Ulm University, Ulm, Germany
- Department of Geriatrics, University Medical Center Göttingen, Göttingen,
Germany
| | - Markus Otto
- Department of Neurology, University Hospital Halle (Saale), Halle,
Germany
| | | | | | - Dörte Polivka
- Department of Neurology, Ulm University, Ulm, Germany
| | - Patrick Fissler
- Department of Neurology, Ulm University, Ulm, Germany
- Psychiatric Services of Thurgovia (Academic Teaching Hospital of Medical
University Salzburg), Münsterlingen, Switzerland
| | - Joachim Strobel
- Department of Nuclear Medicine, Ulm University, Ulm,
Germany
| | - Peter Kletting
- Department of Nuclear Medicine, Medical Radiation Physics, Ulm
University, Ulm, Germany
- Department of Nuclear Medicine, Ulm University, Ulm,
Germany
| | - Matthias W. Riepe
- Department of Psychiatry and Psychotherapy II, Ulm University, Ulm,
Germany
| | - Makoto Higuchi
- National Institute of Radiological Sciences, Chiba,
Japan
| | - Gerhard Glatting
- Department of Nuclear Medicine, Medical Radiation Physics, Ulm
University, Ulm, Germany
- Department of Nuclear Medicine, Ulm University, Ulm,
Germany
| | - Albert Ludolph
- Department of Neurology, Ulm University, Ulm, Germany
- German Center for Neurodegerative Diseases (DZNE), Ulm,
Germany
| | - Ambros J. Beer
- Department of Nuclear Medicine, Ulm University, Ulm,
Germany
| | | |
Collapse
|
4
|
McMurray L, Macdonald JA, Ramakrishnan NK, Zhao Y, Williamson DW, Tietz O, Zhou X, Kealey S, Fagan SG, Smolek T, Cubinkova V, Žilka N, Spillantini MG, Tolkovsky AM, Goedert M, Aigbirhio FI. Synthesis and Assessment of Novel Probes for Imaging Tau Pathology in Transgenic Mouse and Rat Models. ACS Chem Neurosci 2021; 12:1885-1893. [PMID: 33689290 PMCID: PMC8176454 DOI: 10.1021/acschemneuro.0c00790] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Aggregated tau protein is a core pathology present in several neurodegenerative diseases. Therefore, the development and application of positron emission tomography (PET) imaging radiotracers that selectively bind to aggregated tau in fibril form is of importance in furthering the understanding of these disorders. While radiotracers used in human PET studies offer invaluable insight, radiotracers that are also capable of visualizing tau fibrils in animal models are important tools for translational research into these diseases. Herein, we report the synthesis and characterization of a novel library of compounds based on the phenyl/pyridinylbutadienylbenzothiazoles/benzothiazolium (PBB3) backbone developed for this application. From this library, we selected the compound LM229, which binds to recombinant tau fibrils with high affinity (Kd = 3.6 nM) and detects with high specificity (a) pathological 4R tau aggregates in living cultured neurons and mouse brain sections from transgenic human P301S tau mice, (b) truncated human 151-351 3R (SHR24) and 4R (SHR72) tau aggregates in transgenic rat brain sections, and (c) tau neurofibrillary tangles in brain sections from Alzheimer's disease (3R/4R tau) and progressive supranuclear palsy (4R tau). With LM229 also shown to cross the blood-brain barrier in vivo and its effective radiolabeling with the radioisotope carbon-11, we have established a novel platform for PET translational studies using rodent transgenic tau models.
Collapse
Affiliation(s)
- Lindsay McMurray
- Molecular Imaging Chemistry Laboratory, Wolfson Brain Imaging Centre, University of Cambridge, Cambridge CB2 0QQ, United Kingdom
| | | | - Nisha Kuzhuppilly Ramakrishnan
- Molecular Imaging Chemistry Laboratory, Wolfson Brain Imaging Centre, University of Cambridge, Cambridge CB2 0QQ, United Kingdom
| | - Yanyan Zhao
- Molecular Imaging Chemistry Laboratory, Wolfson Brain Imaging Centre, University of Cambridge, Cambridge CB2 0QQ, United Kingdom
| | - David W. Williamson
- Molecular Imaging Chemistry Laboratory, Wolfson Brain Imaging Centre, University of Cambridge, Cambridge CB2 0QQ, United Kingdom
| | - Ole Tietz
- Molecular Imaging Chemistry Laboratory, Wolfson Brain Imaging Centre, University of Cambridge, Cambridge CB2 0QQ, United Kingdom
| | - Xiaoyun Zhou
- Molecular Imaging Chemistry Laboratory, Wolfson Brain Imaging Centre, University of Cambridge, Cambridge CB2 0QQ, United Kingdom
| | - Steven Kealey
- Molecular Imaging Chemistry Laboratory, Wolfson Brain Imaging Centre, University of Cambridge, Cambridge CB2 0QQ, United Kingdom
| | - Steven G. Fagan
- Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0QQ, United Kingdom
| | - Tomáš Smolek
- Axon Neuroscience R&D Services SE, Bratislava, Slovak Republic 811 02
| | | | - Norbert Žilka
- Axon Neuroscience R&D Services SE, Bratislava, Slovak Republic 811 02
| | - Maria Grazia Spillantini
- Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0QQ, United Kingdom
| | - Aviva M. Tolkovsky
- Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0QQ, United Kingdom
| | - Michel Goedert
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom
| | - Franklin I. Aigbirhio
- Molecular Imaging Chemistry Laboratory, Wolfson Brain Imaging Centre, University of Cambridge, Cambridge CB2 0QQ, United Kingdom
- Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0QQ, United Kingdom
| |
Collapse
|
5
|
Tamil Selvan S, Ravichandar R, Kanta Ghosh K, Mohan A, Mahalakshmi P, Gulyás B, Padmanabhan P. Coordination chemistry of ligands: Insights into the design of amyloid beta/tau-PET imaging probes and nanoparticles-based therapies for Alzheimer’s disease. Coord Chem Rev 2021. [DOI: 10.1016/j.ccr.2020.213659] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
|
6
|
Drzezga A, Bischof GN, Giehl K, van Eimeren T. PET and SPECT Imaging of Neurodegenerative Diseases. Mol Imaging 2021. [DOI: 10.1016/b978-0-12-816386-3.00085-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
|
7
|
Franceschi AM, Clifton M, Naser-Tavakolian K, Ahmed O, Cruciata G, Bangiyev L, Clouston S, Franceschi D. ( 18F)-Fluorodeoxyglucose positron emission tomography/magnetic resonance imaging assessment of hypometabolism patterns in clinical phenotypes of suspected corticobasal degeneration. World J Nucl Med 2020; 20:176-184. [PMID: 34321971 PMCID: PMC8286003 DOI: 10.4103/wjnm.wjnm_62_20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 05/22/2020] [Accepted: 06/06/2020] [Indexed: 11/30/2022] Open
Abstract
Corticobasal degeneration (CBD) is a rare neurodegenerative disorder presenting with atypical parkinsonian symptoms that characteristically involves the frontoparietal region including the primary sensorimotor cortex, ipsilateral basal ganglia, and thalamus, typically in an asymmetric pattern. We aim to evaluate the metabolic and volumetric abnormalities in patients with clinically suspected CBD phenotypes utilizing hybrid 18F-fluorodeoxyglucose (FDG) positron emission tomography–magnetic resonance (PET/ MR) brain imaging. A retrospective analysis was performed on 75 patients (mean age 74 years, 31 males and 44 females) who underwent 18F-FDG PET/MR imaging (MRI) as part of their clinical dementia workup. Images were obtained using an integrated Siemens mMR 3T PET/MRI scanner. Two board-certified neuroradiologists and a nuclear medicine physician evaluated the metabolic and volumetric data of each hemisphere to assess for symmetric or asymmetric involvement of regions of interest in the subset of patients with suspected CBD. Of the 75 patients, 12 were diagnosed with suspected CBD based on a combination of clinical symptoms, neurocognitive testing, and hybrid neuroimaging findings. Ten of 12 patients (87%) demonstrated asymmetrically decreased FDG uptake involving a single cerebral hemisphere and ipsilateral subcortical structures, whereas two of 12 patients (13%) demonstrated striking hypometabolism of the bilateral sensorimotor cortices. Our study highlights two characteristic patterns of hypometabolism in patients with clinical and neuroimaging findings suggestive of the underlying CBD. The first pattern is asymmetric hypometabolism and volume loss, particularly within the frontoparietal and occipital cortices with involvement of ipsilateral subcortical structures, including the basal ganglia and thalamus. The second, more atypical pattern, is symmetric hypometabolism with striking involvement of the bilateral sensorimotor cortices.
Collapse
Affiliation(s)
- Ana M Franceschi
- Department of Radiology, Neuroradiology Section, Donald and Barbara Zucker School of Medicine at Hofstra/Northwell Health, Manhasset, NY, USA
| | - Michael Clifton
- Department of Radiology, Population and Preventative Medicine, SUNY Stony Brook, Stony Brook, NY, USA
| | - Kiyon Naser-Tavakolian
- Department of Radiology, Population and Preventative Medicine, SUNY Stony Brook, Stony Brook, NY, USA
| | - Osama Ahmed
- Department of Radiology, Population and Preventative Medicine, SUNY Stony Brook, Stony Brook, NY, USA
| | - Giuseppe Cruciata
- Department of Radiology, Population and Preventative Medicine, SUNY Stony Brook, Stony Brook, NY, USA
| | - Lev Bangiyev
- Department of Radiology, Population and Preventative Medicine, SUNY Stony Brook, Stony Brook, NY, USA
| | - Sean Clouston
- Department of Family, Population and Preventative Medicine, SUNY Stony Brook, Stony Brook, NY, USA
| | - Dinko Franceschi
- Department of Radiology, Population and Preventative Medicine, SUNY Stony Brook, Stony Brook, NY, USA
| |
Collapse
|
8
|
The chemistry of labeling heterocycles with carbon-11 or fluorine-18 for biomedical imaging. ADVANCES IN HETEROCYCLIC CHEMISTRY 2020. [DOI: 10.1016/bs.aihch.2019.11.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
|
9
|
Narumi T, Nishizawa T, Imai T, Kyan R, Taniguchi H, Sato K, Mase N. Improvement of chemical stability of conjugated dienes by chlorine substitution. Tetrahedron 2018. [DOI: 10.1016/j.tet.2018.09.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
10
|
Synthesis of carbon-11-labeled 5-HT6R antagonists as new candidate PET radioligands for imaging of Alzheimer’s disease. Bioorg Med Chem Lett 2018; 28:1836-1841. [DOI: 10.1016/j.bmcl.2018.04.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 04/04/2018] [Accepted: 04/06/2018] [Indexed: 12/31/2022]
|
11
|
Gao M, Wang M, Zheng QH. Synthesis of carbon-11-labeled CK1 inhibitors as new potential PET radiotracers for imaging of Alzheimer's disease. Bioorg Med Chem Lett 2018; 28:2234-2238. [PMID: 29859907 DOI: 10.1016/j.bmcl.2018.05.053] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 05/27/2018] [Accepted: 05/28/2018] [Indexed: 12/13/2022]
Abstract
The reference standards methyl 3-((2,2-difluoro-5H-[1,3]dioxolo[4',5':4,5]benzo[1,2-d]imidazol-6-yl)carbamoyl)benzoate (5a) and N-(2,2-difluoro-5H-[1,3]dioxolo[4',5':4,5]benzo[1,2-d]imidazol-6-yl)-3-methoxybenzamide (5c), and their corresponding desmethylated precursors 3-((2,2-difluoro-5H-[1,3]dioxolo[4',5':4,5]benzo[1,2-d]imidazol-6-yl)carbamoyl)benzoic acid (6a) and N-(2,2-difluoro-5H-[1,3]dioxolo[4',5':4,5]benzo[1,2-d]imidazol-6-yl)-3-hydroxybenzamide (6b), were synthesized from 5-amino-2,2-difluoro-1,3-benzodioxole and 3-substituted benzoic acids in 5 and 6 steps with 33% and 11%, 30% and 7% overall chemical yield, respectively. Carbon-11-labeled casein kinase 1 (CK1) inhibitors, [11C]methyl 3-((2,2-difluoro-5H-[1,3]dioxolo[4',5':4,5]benzo[1,2-d]imidazol-6-yl)carbamoyl)benzoate ([11C]5a) and N-(2,2-difluoro-5H-[1,3]dioxolo[4',5':4,5]benzo[1,2-d]imidazol-6-yl)-3-[11C]methoxybenzamide ([11C]5c), were prepared from their O-desmethylated precursor 6a or 6b with [11C]CH3OTf through O-[11C]methylation and isolated by HPLC combined with SPE in 40-45% radiochemical yield, based on [11C]CO2 and decay corrected to end of bombardment (EOB). The radiochemical purity was >99%, and the molar activity (MA) at EOB was 370-740 GBq/μmol with a total synthesis time of ∼40-min from EOB.
Collapse
Affiliation(s)
- Mingzhang Gao
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, 1345 West 16th Street, Room 202, Indianapolis, IN 46202, USA
| | - Min Wang
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, 1345 West 16th Street, Room 202, Indianapolis, IN 46202, USA
| | - Qi-Huang Zheng
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, 1345 West 16th Street, Room 202, Indianapolis, IN 46202, USA.
| |
Collapse
|
12
|
Iqbal K, Liu F, Gong CX. Recent developments with tau-based drug discovery. Expert Opin Drug Discov 2018; 13:399-410. [DOI: 10.1080/17460441.2018.1445084] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Khalid Iqbal
- Department of Neurochemistry, Inge Grundke-Iqbal Research Floor, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, NY, USA
| | - Fei Liu
- Department of Neurochemistry, Inge Grundke-Iqbal Research Floor, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, NY, USA
| | - Cheng-Xin Gong
- Department of Neurochemistry, Inge Grundke-Iqbal Research Floor, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, NY, USA
| |
Collapse
|
13
|
Bartels B, Cueni P, Muri D, Koerner M. Development of a safe and scalable route towards a tau PET tracer precursor. Bioorg Med Chem 2018; 26:970-976. [PMID: 29074348 DOI: 10.1016/j.bmc.2017.10.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 10/06/2017] [Accepted: 10/11/2017] [Indexed: 11/16/2022]
Abstract
A scalable 5-step synthesis of the diazacarbazole derivative 1 used as tau PET tracer precursor is reported. Key features of this synthesis include a Buchwald-Hartwig amination, a Pd catalyzed CH activation and a Suzuki-Miyaura cross-coupling.
Collapse
Affiliation(s)
- Bjoern Bartels
- Pharma Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., CH-4070 Basel, Switzerland
| | - Philipp Cueni
- Pharma Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., CH-4070 Basel, Switzerland
| | - Dieter Muri
- Pharma Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., CH-4070 Basel, Switzerland
| | - Matthias Koerner
- Pharma Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., CH-4070 Basel, Switzerland.
| |
Collapse
|
14
|
Synthesis of N -(3-(4-[ 11 C]methylpiperazin-1-yl)−1-(5-methylpyridin-2-yl)−1 H -pyrazol-5-yl)pyrazolo[1,5- a ]pyrimidine-3-carboxamide as a new potential PET agent for imaging of IRAK4 enzyme in neuroinflammation. Appl Radiat Isot 2018; 132:6-12. [DOI: 10.1016/j.apradiso.2017.11.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Revised: 10/17/2017] [Accepted: 11/05/2017] [Indexed: 12/19/2022]
|
15
|
Rejc L, Šmid L, Kepe V, Podlipnik Č, Golobič A, Bresjanac M, Barrio JR, Petrič A, Košmrlj J. Design, Syntheses, and in Vitro Evaluation of New Fluorine-18 Radiolabeled Tau-Labeling Molecular Probes. J Med Chem 2017; 60:8741-8757. [DOI: 10.1021/acs.jmedchem.7b00764] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Luka Rejc
- Faculty
of Chemistry and Chemical Technology, University of Ljubljana, Večna
pot 113, SI-1000 Ljubljana, Slovenia
| | - Lojze Šmid
- Faculty
of Medicine, Institute of Pathological Physiology, University of Ljubljana, Zaloška 4, SI-1001 Ljubljana, Slovenia
| | - Vladimir Kepe
- Department
of Molecular and Medical Pharmacology, The David Geffen School of
Medicine, University of California, Los Angeles, California 90095, United States
| | - Črtomir Podlipnik
- Faculty
of Chemistry and Chemical Technology, University of Ljubljana, Večna
pot 113, SI-1000 Ljubljana, Slovenia
| | - Amalija Golobič
- Faculty
of Chemistry and Chemical Technology, University of Ljubljana, Večna
pot 113, SI-1000 Ljubljana, Slovenia
| | - Mara Bresjanac
- Faculty
of Medicine, Institute of Pathological Physiology, University of Ljubljana, Zaloška 4, SI-1001 Ljubljana, Slovenia
| | - Jorge R. Barrio
- Department
of Molecular and Medical Pharmacology, The David Geffen School of
Medicine, University of California, Los Angeles, California 90095, United States
| | - Andrej Petrič
- Faculty
of Chemistry and Chemical Technology, University of Ljubljana, Večna
pot 113, SI-1000 Ljubljana, Slovenia
- EN-FIST Centre of Excellence, Trg Osvobodilne fronte 13, SI-1000 Ljubljana, Slovenia
| | - Janez Košmrlj
- Faculty
of Chemistry and Chemical Technology, University of Ljubljana, Večna
pot 113, SI-1000 Ljubljana, Slovenia
| |
Collapse
|
16
|
Bischof GN, Endepols H, van Eimeren T, Drzezga A. Tau-imaging in neurodegeneration. Methods 2017; 130:114-123. [PMID: 28790016 DOI: 10.1016/j.ymeth.2017.08.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Revised: 07/25/2017] [Accepted: 08/04/2017] [Indexed: 10/19/2022] Open
Abstract
Pathological cerebral aggregations of proteins are suggested to play a crucial role in the development of neurodegenerative disorders. For example, aggregation of the protein ß-amyloid in form of extracellular amyloid-plaques as well as intraneuronal depositions of the protein tau in form of neurofibrillary tangles represent hallmarks of Alzheimer's disease (AD). Recently, novel tracers for in vivo molecular imaging of tau-aggregates in the brain have been introduced, complementing existing tracers for imaging amyloid-plaques. Available data on these novel tracers indicate that the subject of Tau-PET may be of considerable complexity. On the one hand this refers to the various forms of appearance of tau-pathology in different types of neurodegenerative disorders. On the other hand, a number of hurdles regarding validation of these tracers still need to be overcome with regard to comparability and standardization of the different tracers, observed off-target/non-specific binding and quantitative interpretation of the signal. These issues will have to be clarified before systematic clinical application of this exciting new methodological approach may become possible. Potential applications refer to early detection of neurodegeneration, differential diagnosis between tauopathies and non-tauopathies and specific patient selection and follow-up in therapy trials.
Collapse
Affiliation(s)
| | - Heike Endepols
- Department of Nuclear Medicine, University of Cologne, Germany
| | - Thilo van Eimeren
- Department of Nuclear Medicine, University of Cologne, Germany; German Research Center for Neurodegenerative Diseases (DZNE), Germany
| | - Alexander Drzezga
- Department of Nuclear Medicine, University of Cologne, Germany; German Research Center for Neurodegenerative Diseases (DZNE), Germany.
| |
Collapse
|
17
|
Synthesis and preliminary biological evaluation of radiolabeled 5-BDBD analogs as new candidate PET radioligands for P2X4 receptor. Bioorg Med Chem 2017; 25:3835-3844. [PMID: 28554730 DOI: 10.1016/j.bmc.2017.05.031] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Revised: 05/10/2017] [Accepted: 05/15/2017] [Indexed: 01/01/2023]
Abstract
P2X4 receptor has become an interesting molecular target for treatment and PET imaging of neuroinflammation and associated brain diseases such as Alzheimer's disease. This study reports the first design, synthesis, radiolabeling and biological evaluation of new candidate PET P2X4 receptor radioligands using 5-BDBD, a specific P2X4 receptor antagonist, as a scaffold. 5-(3-Hydroxyphenyl)-1-[11C]methyl-1,3-dihydro-2H-benzofuro[3,2-e][1,4]diazepin-2-one (N-[11C]Me-5-BDBD analog, [11C]9) and 5-(3-Bromophenyl)-1-[11C]methyl-1,3-dihydro-2H-benzofuro[3,2-e][1,4]diazepin-2-one (N-[11C]Me-5-BDBD, [11C]8c) were prepared from their corresponding desmethylated precursors with [11C]CH3OTf through N-[11C]methylation and isolated by HPLC combined with SPE in 30-50% decay corrected radiochemical yields with 370-1110GBq/µmol specific activity at EOB. 5-(3-[18F]Fluorophenyl)-1,3-dihydro-2H-benzofuro[3,2-e][1,4]diazepin-2-one ([18F]F-5-BDBD, [18F]5a) and 5-(3-(2-[18F]fluoroethoxy)phenyl)-1,3-dihydro-2H-benzofuro[3,2-e][1,4]diazepin-2-one ([18F]FE-5-BDBD, [18F]11) were prepared from their corresponding nitro- and tosylated precursors by nucleophilic substitution with K[18F]F/Kryptofix 2.2.2 and isolated by HPLC-SPE in 5-25% decay corrected radiochemical yields with 111-740GBq/µmol specific activity at EOB. The preliminary biological evaluation of radiolabeled 5-BDBD analogs indicated these new radioligands have similar biological activity with their parent compound 5-BDBD.
Collapse
|
18
|
Saint-Aubert L, Lemoine L, Chiotis K, Leuzy A, Rodriguez-Vieitez E, Nordberg A. Tau PET imaging: present and future directions. Mol Neurodegener 2017; 12:19. [PMID: 28219440 PMCID: PMC5319037 DOI: 10.1186/s13024-017-0162-3] [Citation(s) in RCA: 202] [Impact Index Per Article: 28.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 02/15/2017] [Indexed: 12/15/2022] Open
Abstract
Abnormal aggregation of tau in the brain is a major contributing factor in various neurodegenerative diseases. The role of tau phosphorylation in the pathophysiology of tauopathies remains unclear. Consequently, it is important to be able to accurately and specifically target tau deposits in vivo in the brains of patients. The advances of molecular imaging in the recent years have now led to the recent development of promising tau-specific tracers for positron emission tomography (PET), such as THK5317, THK5351, AV-1451, and PBB3. These tracers are now available for clinical assessment in patients with various tauopathies, including Alzheimer's disease, as well as in healthy subjects. Exploring the patterns of tau deposition in vivo for different pathologies will allow discrimination between neurodegenerative diseases, including different tauopathies, and monitoring of disease progression. The variety and complexity of the different types of tau deposits in the different diseases, however, has resulted in quite a challenge for the development of tau PET tracers. Extensive work remains in order to fully characterize the binding properties of the tau PET tracers, and to assess their usefulness as an early biomarker of the underlying pathology. In this review, we summarize recent findings on the most promising tau PET tracers to date, discuss what has been learnt from these findings, and offer some suggestions for the next steps that need to be achieved in a near future.
Collapse
Affiliation(s)
- Laure Saint-Aubert
- Department NVS, Center for Alzheimer Research, Division of Translational Alzheimer Neurobiology, Karolinska Institutet, Novum 5th floor, 141 57, Huddinge, Sweden
| | - Laetitia Lemoine
- Department NVS, Center for Alzheimer Research, Division of Translational Alzheimer Neurobiology, Karolinska Institutet, Novum 5th floor, 141 57, Huddinge, Sweden
| | - Konstantinos Chiotis
- Department NVS, Center for Alzheimer Research, Division of Translational Alzheimer Neurobiology, Karolinska Institutet, Novum 5th floor, 141 57, Huddinge, Sweden
| | - Antoine Leuzy
- Department NVS, Center for Alzheimer Research, Division of Translational Alzheimer Neurobiology, Karolinska Institutet, Novum 5th floor, 141 57, Huddinge, Sweden
| | - Elena Rodriguez-Vieitez
- Department NVS, Center for Alzheimer Research, Division of Translational Alzheimer Neurobiology, Karolinska Institutet, Novum 5th floor, 141 57, Huddinge, Sweden
| | - Agneta Nordberg
- Department NVS, Center for Alzheimer Research, Division of Translational Alzheimer Neurobiology, Karolinska Institutet, Novum 5th floor, 141 57, Huddinge, Sweden. .,Department of Geriatric Medicine, Karolinska University Hospital Huddinge, Stockholm, Sweden.
| |
Collapse
|
19
|
Rombouts FJR, Andrés JI, Ariza M, Alonso JM, Austin N, Bottelbergs A, Chen L, Chupakhin V, Cleiren E, Fierens K, Fontana A, Langlois X, Leenaerts JE, Mariën J, Martínez Lamenca C, Salter R, Schmidt ME, Te Riele P, Wintmolders C, Trabanco AA, Zhang W, Macdonald G, Moechars D. Discovery of N-(Pyridin-4-yl)-1,5-naphthyridin-2-amines as Potential Tau Pathology PET Tracers for Alzheimer's Disease. J Med Chem 2017; 60:1272-1291. [PMID: 28106992 DOI: 10.1021/acs.jmedchem.6b01173] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
A mini-HTS on 4000 compounds selected using 2D fragment-based similarity and 3D pharmacophoric and shape similarity to known selective tau aggregate binders identified N-(6-methylpyridin-2-yl)quinolin-2-amine 10 as a novel potent binder to human AD aggregated tau with modest selectivity versus aggregated β-amyloid (Aβ). Initial medicinal chemistry efforts identified key elements for potency and selectivity, as well as suitable positions for radiofluorination, leading to a first generation of fluoroalkyl-substituted quinoline tau binding ligands with suboptimal physicochemical properties. Further optimization toward a more optimal pharmacokinetic profile led to the discovery of 1,5-naphthyridine 75, a potent and selective tau aggregate binder with potential as a tau PET tracer.
Collapse
Affiliation(s)
- Frederik J R Rombouts
- Neuroscience Medicinal Chemistry, Janssen Research & Development, Janssen Pharmaceutica N. V. , Turnhoutseweg 30, B-2340 Beerse, Belgium
| | - José-Ignacio Andrés
- Discovery Sciences, Janssen Research & Development, Janssen-Cilag S. A. , C/Jarama 75A, 45007 Toledo, Spain
| | - Manuela Ariza
- Neuroscience Medicinal Chemistry, Janssen Research & Development, Janssen Pharmaceutica N. V. , Turnhoutseweg 30, B-2340 Beerse, Belgium
| | - José Manuel Alonso
- Discovery Sciences, Janssen Research & Development, Janssen-Cilag S. A. , C/Jarama 75A, 45007 Toledo, Spain
| | - Nigel Austin
- Discovery Sciences, Janssen Research & Development, Janssen Pharmaceutica N. V. , Turnhoutseweg 30, B-2340 Beerse, Belgium
| | - Astrid Bottelbergs
- Discovery Sciences, Janssen Research & Development, Janssen-Cilag S. A. , C/Jarama 75A, 45007 Toledo, Spain
| | - Lu Chen
- Isotope Chemistry and Biotransformation, Janssen Research & Development , Welsh & McKean Roads, Spring House, Pennsylvania 19477, United States
| | - Vladimir Chupakhin
- Discovery Sciences, Janssen Research & Development, Janssen Pharmaceutica N. V. , Turnhoutseweg 30, B-2340 Beerse, Belgium
| | - Erna Cleiren
- Discovery Sciences, Janssen Research & Development, Janssen Pharmaceutica N. V. , Turnhoutseweg 30, B-2340 Beerse, Belgium
| | - Katleen Fierens
- Discovery Sciences, Janssen Research & Development, Janssen Pharmaceutica N. V. , Turnhoutseweg 30, B-2340 Beerse, Belgium
| | - Alberto Fontana
- Discovery Sciences, Janssen Research & Development, Janssen-Cilag S. A. , C/Jarama 75A, 45007 Toledo, Spain
| | - Xavier Langlois
- Neuroscience Biology, Janssen Research & Development, Janssen Pharmaceutica N. V. , Turnhoutseweg 30, B-2340 Beerse, Belgium
| | - Joseph E Leenaerts
- Neuroscience Medicinal Chemistry, Janssen Research & Development, Janssen Pharmaceutica N. V. , Turnhoutseweg 30, B-2340 Beerse, Belgium
| | - Jonas Mariën
- Neuroscience Biology, Janssen Research & Development, Janssen Pharmaceutica N. V. , Turnhoutseweg 30, B-2340 Beerse, Belgium
| | - Carolina Martínez Lamenca
- Neuroscience Medicinal Chemistry, Janssen Research & Development, Janssen Pharmaceutica N. V. , Turnhoutseweg 30, B-2340 Beerse, Belgium
| | - Rhys Salter
- Isotope Chemistry and Biotransformation, Janssen Research & Development , Welsh & McKean Roads, Spring House, Pennsylvania 19477, United States
| | - Mark E Schmidt
- Neuroscience Experimental Medicine, Janssen Early Development, Janssen Pharmaceutica N. V. , Turnhoutseweg 30, B-2340 Beerse, Belgium
| | - Paula Te Riele
- Neuroscience Biology, Janssen Research & Development, Janssen Pharmaceutica N. V. , Turnhoutseweg 30, B-2340 Beerse, Belgium
| | - Cindy Wintmolders
- Neuroscience Biology, Janssen Research & Development, Janssen Pharmaceutica N. V. , Turnhoutseweg 30, B-2340 Beerse, Belgium
| | - Andrés A Trabanco
- Neuroscience Medicinal Chemistry, Janssen Research & Development, Janssen-Cilag S. A. , C/Jarama 75A, 45007 Toledo, Spain
| | - Wei Zhang
- Neuroscience Biomarker Research, Janssen Research & Development , 3210 Merryfield Row, San Diego, California 92121, United States
| | - Gregor Macdonald
- Neuroscience Medicinal Chemistry, Janssen Research & Development, Janssen Pharmaceutica N. V. , Turnhoutseweg 30, B-2340 Beerse, Belgium
| | - Dieder Moechars
- Neuroscience Biology, Janssen Research & Development, Janssen Pharmaceutica N. V. , Turnhoutseweg 30, B-2340 Beerse, Belgium
| |
Collapse
|
20
|
Gao M, Wang M, Zheng QH. Synthesis of carbon-11-labeled isonicotinamides as new potential PET agents for imaging of GSK-3 enzyme in Alzheimer’s disease. Bioorg Med Chem Lett 2017; 27:740-743. [DOI: 10.1016/j.bmcl.2017.01.041] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 01/12/2017] [Accepted: 01/13/2017] [Indexed: 12/29/2022]
|
21
|
Walji AM, Hostetler ED, Selnick H, Zeng Z, Miller P, Bennacef I, Salinas C, Connolly B, Gantert L, Holahan M, O’Malley S, Purcell M, Riffel K, Li J, Balsells J, OBrien JA, Melquist S, Soriano A, Zhang X, Ogawa A, Xu S, Joshi E, Della Rocca J, Hess FJ, Schachter J, Hesk D, Schenk D, Struyk A, Babaoglu K, Lohith TG, Wang Y, Yang K, Fu J, Evelhoch JL, Coleman PJ. Discovery of 6-(Fluoro-18F)-3-(1H-pyrrolo[2,3-c]pyridin-1-yl)isoquinolin-5-amine ([18F]-MK-6240): A Positron Emission Tomography (PET) Imaging Agent for Quantification of Neurofibrillary Tangles (NFTs). J Med Chem 2016; 59:4778-89. [PMID: 27088900 DOI: 10.1021/acs.jmedchem.6b00166] [Citation(s) in RCA: 125] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Abbas M. Walji
- Discovery Chemistry, Merck & Co., Inc., West Point Pennsylvania 19486, United States
| | - Eric D. Hostetler
- Imaging, Merck & Co., Inc., West Point Pennsylvania 19486, United States
| | - Harold Selnick
- Discovery Chemistry, Merck & Co., Inc., West Point Pennsylvania 19486, United States
| | - Zhizhen Zeng
- Imaging, Merck & Co., Inc., West Point Pennsylvania 19486, United States
| | - Patricia Miller
- Imaging, Merck & Co., Inc., West Point Pennsylvania 19486, United States
| | - Idriss Bennacef
- Imaging, Merck & Co., Inc., West Point Pennsylvania 19486, United States
| | - Cristian Salinas
- Imaging, Merck & Co., Inc., West Point Pennsylvania 19486, United States
| | - Brett Connolly
- Imaging, Merck & Co., Inc., West Point Pennsylvania 19486, United States
| | - Liza Gantert
- Imaging, Merck & Co., Inc., West Point Pennsylvania 19486, United States
| | - Marie Holahan
- Imaging, Merck & Co., Inc., West Point Pennsylvania 19486, United States
| | - Stacey O’Malley
- Imaging, Merck & Co., Inc., West Point Pennsylvania 19486, United States
| | - Mona Purcell
- Imaging, Merck & Co., Inc., West Point Pennsylvania 19486, United States
| | - Kerry Riffel
- Imaging, Merck & Co., Inc., West Point Pennsylvania 19486, United States
| | - Jing Li
- Process Chemistry, Merck & Co., Inc., West Point Pennsylvania 19486, United States
| | - Jaume Balsells
- Process Chemistry, Merck & Co., Inc., West Point Pennsylvania 19486, United States
| | - Julie A. OBrien
- Pharmacology, Merck & Co., Inc., West Point Pennsylvania 19486, United States
| | - Stacey Melquist
- Pharmacology, Merck & Co., Inc., West Point Pennsylvania 19486, United States
| | - Aileen Soriano
- Pharmacology, Merck & Co., Inc., Kenilworth, New Jersey 07033, United States
| | - Xiaoping Zhang
- Pharmacology, Merck & Co., Inc., Kenilworth, New Jersey 07033, United States
| | - Aimie Ogawa
- Pharmacology, Merck & Co., Inc., Kenilworth, New Jersey 07033, United States
| | - Serena Xu
- Pharmacology, Merck & Co., Inc., Kenilworth, New Jersey 07033, United States
| | - Elizabeth Joshi
- Drug Metabolism, Merck & Co., Inc., West Point, Pennsylvania 19486, United States
| | - Joseph Della Rocca
- Discovery Pharmaceutical Sciences, Merck & Co., Inc., West Point, Pennsylvania 19486, United States
| | - Fred J. Hess
- Neuroscience, Merck & Co., Inc., West Point, Pennsylvania 19486, United States
| | - Joel Schachter
- Neuroscience, Merck & Co., Inc., West Point, Pennsylvania 19486, United States
| | - David Hesk
- Labelled Compound Synthesis, Merck & Co., Inc., Rahway, New Jersey, 07065, United States
| | - David Schenk
- Labelled Compound Synthesis, Merck & Co., Inc., Rahway, New Jersey, 07065, United States
| | - Arie Struyk
- Clinical Pharmacology, Merck & Co., Inc., West Point, Pennsylvania 19486, United States
| | - Kerim Babaoglu
- Computational Chemistry, Merck & Co., Inc., West Point, Pennsylvania 19486, United States
| | - Talakad G. Lohith
- Imaging, Merck & Co., Inc., West Point Pennsylvania 19486, United States
| | - Yaode Wang
- Pharmaron Beijing Co., Ltd., Beijing 100176, China
| | - Kun Yang
- Pharmaron Beijing Co., Ltd., Beijing 100176, China
| | - Jianmin Fu
- Pharmaron Beijing Co., Ltd., Beijing 100176, China
| | | | - Paul J. Coleman
- Discovery Chemistry, Merck & Co., Inc., West Point Pennsylvania 19486, United States
| |
Collapse
|
22
|
Synthesis of carbon-11-labeled imidazopyridine- and purine-thioacetamide derivatives as new potential PET tracers for imaging of nucleotide pyrophosphatase/phosphodiesterase 1 (NPP1). Bioorg Med Chem Lett 2016; 26:1371-5. [PMID: 26856922 DOI: 10.1016/j.bmcl.2016.01.081] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 01/28/2016] [Accepted: 01/29/2016] [Indexed: 01/07/2023]
Abstract
The target tracer carbon-11-labeled imidazopyridine- and purine-thioacetamide derivatives, N-(3-[(11)C]methoxy-4-methoxyphenyl)-2-((5-methoxy-3H-imidazo[4,5-b]pyridin-2-yl)thio)acetamide (3-[(11)C]4a) and N-(4-[(11)C]methoxy-3-methoxyphenyl)-2-((5-methoxy-3H-imidazo[4,5-b]pyridin-2-yl)thio)acetamide (4-[(11)C]4a); 2-((6-amino-9H-purin-8-yl)thio)-N-(3-[(11)C]methoxy-4-methoxyphenyl)acetamide (3-[(11)C]8a) and 2-((6-amino-9H-purin-8-yl)thio)-N-(4-[(11)C]methoxy-3-methoxyphenyl)acetamide (4-[(11)C]8a), were prepared by O-[(11)C]methylation of their corresponding precursors with [(11)C]CH3OTf under basic condition (2N NaOH) and isolated by a simplified solid-phase extraction (SPE) method in 50-60% radiochemical yields based on [(11)C]CO2 and decay corrected to end of bombardment (EOB). The overall synthesis time from EOB was 23min, the radiochemical purity was >99%, and the specific activity at end of synthesis (EOS) was 185-555GBq/μmol.
Collapse
|