1
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Wright JP, Goodman JR, Lin YG, Lieberman BP, Clemens J, Gomez LF, Liang Q, Hoye AT, Pontecorvo MJ, Conway KA. Monoamine oxidase binding not expected to significantly affect [ 18F]flortaucipir PET interpretation. Eur J Nucl Med Mol Imaging 2022; 49:3797-3808. [PMID: 35596745 PMCID: PMC9399028 DOI: 10.1007/s00259-022-05822-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 04/25/2022] [Indexed: 11/28/2022]
Abstract
Purpose [18F]-labeled positron emission tomography (PET) radioligands permit in vivo assessment of Alzheimer’s disease biomarkers, including aggregated neurofibrillary tau (NFT) with [18F]flortaucipir. Due to structural similarities of flortaucipir with some monoamine oxidase A (MAO-A) inhibitors, this study aimed to evaluate flortaucipir binding to MAO-A and MAO-B and any potential impact on PET interpretation. Methods [18F]Flortaucipir autoradiography was performed on frozen human brain tissue slices, and PET imaging was conducted in rats. Dissociation constants were determined by saturation binding, association and dissociation rates were measured by kinetic binding experiments, and IC50 values were determined by competition binding. Results Under stringent wash conditions, specific [18F]flortaucipir binding was observed on tau NFT-rich Alzheimer’s disease tissue and not control tissue. In vivo PET experiments in rats revealed no evidence of [18F]flortaucipir binding to MAO-A; pre-treatment with MAO inhibitor pargyline did not impact uptake or wash-out of [18F]flortaucipir. [18F]Flortaucipir bound with low nanomolar affinity to human MAO-A in a microsomal preparation in vitro but with a fast dissociation rate relative to MAO-A ligand fluoroethyl-harmol, consistent with no observed in vivo binding in rats of [18F]flortaucipir to MAO-A. Direct binding of flortaucipir to human MAO-B was not detected in a microsomal preparation. A high concentration of flortaucipir (IC50 of 1.3 μM) was found to block binding of the MAO-B ligand safinamide to MAO-B on microsomes suggesting that, at micromolar concentrations, flortaucipir weakly binds to MAO-B in vitro. Conclusion These data suggest neither MAO-A nor MAO-B binding will contribute significantly to the PET signal in cortical target areas relevant to the interpretation of [18F]flortaucipir. Supplementary Information The online version contains supplementary material available at 10.1007/s00259-022-05822-9.
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Affiliation(s)
- Justin P Wright
- Avid Radiopharmaceuticals, Eli Lilly & Company, Philadelphia, PA, USA
| | - Jason R Goodman
- Avid Radiopharmaceuticals, Eli Lilly & Company, Philadelphia, PA, USA
| | - Yin-Guo Lin
- Avid Radiopharmaceuticals, Eli Lilly & Company, Philadelphia, PA, USA
| | - Brian P Lieberman
- Avid Radiopharmaceuticals, Eli Lilly & Company, Philadelphia, PA, USA
| | - Jennifer Clemens
- Avid Radiopharmaceuticals, Eli Lilly & Company, Philadelphia, PA, USA
| | - Luis F Gomez
- Avid Radiopharmaceuticals, Eli Lilly & Company, Philadelphia, PA, USA
| | - Qianwa Liang
- Avid Radiopharmaceuticals, Eli Lilly & Company, Philadelphia, PA, USA
| | - Adam T Hoye
- Avid Radiopharmaceuticals, Eli Lilly & Company, Philadelphia, PA, USA
| | | | - Kelly A Conway
- Avid Radiopharmaceuticals, Eli Lilly & Company, Philadelphia, PA, USA.
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2
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Debnath S, Parveen S, Pradhan P, Das I, Das T. Benzo[4,5]imidazo[1,2- a]pyridines and benzo[4,5]imidazo[1,2- a]pyrimidines: recent advancements in synthesis of two diversely important heterocyclic motifs and their derivatives. NEW J CHEM 2022. [DOI: 10.1039/d2nj00546h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Nitrogen heterocycles are some of the most important compounds that are found in nature or synthesized otherwise.
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Affiliation(s)
| | - Syaleena Parveen
- Department of Chemistry, NIT Jamshedpur, Jamshedpur 831014, India
| | | | - Ipsita Das
- Department of Chemistry, NIT Jamshedpur, Jamshedpur 831014, India
| | - Tapas Das
- Department of Chemistry, NIT Jamshedpur, Jamshedpur 831014, India
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3
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Pyrimido[1,2- a]benzimidazoles: synthesis and perspective of their pharmacological use. Chem Heterocycl Compd (N Y) 2021; 57:383-409. [PMID: 34024913 PMCID: PMC8121645 DOI: 10.1007/s10593-021-02916-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 01/12/2021] [Indexed: 01/26/2023]
Abstract
The review presents data on the synthesis as well as studies of biological activity of new derivatives of pyrimido[1,2-a]benzimidazoles published over the last decade. The bibliography of the review includes 136 sources.
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4
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Klenner MA, Pascali G, Fraser BH, Darwish TA. Kinetic isotope effects and synthetic strategies for deuterated carbon-11 and fluorine-18 labelled PET radiopharmaceuticals. Nucl Med Biol 2021; 96-97:112-147. [PMID: 33892374 DOI: 10.1016/j.nucmedbio.2021.03.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 03/19/2021] [Accepted: 03/30/2021] [Indexed: 11/22/2022]
Abstract
The deuterium labelling of pharmaceuticals is a useful strategy for altering pharmacokinetic properties, particularly for improving metabolic resistance. The pharmacological effects of such metabolites are often assumed to be negligible during standard drug discovery and are factored in later at the clinical phases of development, where the risks and benefits of the treatment and side-effects can be wholly assessed. This paradigm does not translate to the discovery of radiopharmaceuticals, however, as the confounding effects of radiometabolites can inevitably show in preliminary positron emission tomography (PET) scans and thus complicate interpretation. Consequently, the formation of radiometabolites is crucial to take into consideration, compared to non-radioactive metabolites, and the application of deuterium labelling is a particularly attractive approach to minimise radiometabolite formation. Herein, we provide a comprehensive overview of the deuterated carbon-11 and fluorine-18 radiopharmaceuticals employed in PET imaging experiments. Specifically, we explore six categories of deuterated radiopharmaceuticals used to investigate the activities of monoamine oxygenase (MAO), choline, translocator protein (TSPO), vesicular monoamine transporter 2 (VMAT2), neurotransmission and the diagnosis of Alzheimer's disease; from which we derive four prominent deuteration strategies giving rise to a kinetic isotope effect (KIE) for reducing the rate of metabolism. Synthetic approaches for over thirty of these deuterated radiopharmaceuticals are discussed from the perspective of deuterium and radioisotope incorporation, alongside an evaluation of the deuterium labelling and radiolabelling efficacies across these independent studies. Clinical and manufacturing implications are also discussed to provide a more comprehensive overview of how deuterated radiopharmaceuticals may be introduced to routine practice.
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Affiliation(s)
- Mitchell A Klenner
- National Deuteration Facility (NDF) & Human Health, Australian Nuclear Science and Technology Organisation (ANSTO), Lucas Heights, NSW 2234, Australia; Department of Nuclear Medicine and PET, Liverpool Hospital, Liverpool, NSW 2170, Australia.
| | - Giancarlo Pascali
- National Deuteration Facility (NDF) & Human Health, Australian Nuclear Science and Technology Organisation (ANSTO), Lucas Heights, NSW 2234, Australia; Department of Nuclear Medicine and PET, Prince of Wales Hospital, Randwick, NSW 2031, Australia; School of Chemistry, University of New South Wales (UNSW), Kensington, NSW 2052, Australia
| | - Benjamin H Fraser
- National Deuteration Facility (NDF) & Human Health, Australian Nuclear Science and Technology Organisation (ANSTO), Lucas Heights, NSW 2234, Australia
| | - Tamim A Darwish
- National Deuteration Facility (NDF) & Human Health, Australian Nuclear Science and Technology Organisation (ANSTO), Lucas Heights, NSW 2234, Australia
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5
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Gabellieri E, Capotosti F, Molette J, Sreenivasachary N, Mueller A, Berndt M, Schieferstein H, Juergens T, Varisco Y, Oden F, Schmitt-Willich H, Hickman D, Dinkelborg L, Stephens A, Pfeifer A, Kroth H. Discovery of 2-(4-(2-fluoroethoxy)piperidin-1-yl)-9-methyl-9H-pyrrolo[2,3-b:4,5-c']dipyridine ([18F]PI-2014) as PET tracer for the detection of pathological aggregated tau in Alzheimer's disease and other tauopathies. Eur J Med Chem 2020; 204:112615. [PMID: 32771872 DOI: 10.1016/j.ejmech.2020.112615] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 06/04/2020] [Accepted: 06/21/2020] [Indexed: 12/29/2022]
Abstract
The compound screening was initiated with a direct staining assay to identify compounds binding to Tau aggregates and not Abeta plaques using human brain sections derived from late stage Alzheimer's disease donors. The binding of Tau aggregate selective compounds was then quantitatively assessed with human brain derived paired helical filaments utilizing the label-free Back Scattering Interferometry assay. In vivo biodistribution experiments of selected fluorine-18 labeled compounds were performed in mice to assess brain uptake, brain washout, and defluorination. Compound 11 emerged as the most promising candidate, displaying high in vitro binding affinity and selectivity to neurofibrillary tangles. Fluorine-18 labeled compound 11 showed high brain uptake and rapid washout from the mouse brain with no observed bone uptake. Furthermore, compound 11 was able to detect Tau aggregates in tauopathy brain sections from corticobasal degeneration, progressive supranuclear palsy, and Pick's disease donors. Thus, 2-(4-(2-fluoroethoxy)piperidin-1-yl)-9-methyl-9H-pyrrolo[2,3-b:4,5-c']dipyridine (PI-2014, compound 11) was selected for characterization in a first-in-human study.
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Affiliation(s)
| | | | - Jerome Molette
- AC Immune SA, EPFL Innovation Park, Building B, 1015, Lausanne, Switzerland
| | | | - Andre Mueller
- Life Molecular Imaging GmbH, Tegeler Strasse 6-7, 13353, Berlin, Germany
| | - Mathias Berndt
- Life Molecular Imaging GmbH, Tegeler Strasse 6-7, 13353, Berlin, Germany
| | - Hanno Schieferstein
- Formerly Piramal Imaging GmbH, Tegeler Strasse 6-7, 13353, Berlin, Germany; Merck KGaA, Frankfurter Strasse 250, 64293, Darmstadt, Germany
| | - Tanja Juergens
- AC Immune SA, EPFL Innovation Park, Building B, 1015, Lausanne, Switzerland
| | - Yvan Varisco
- AC Immune SA, EPFL Innovation Park, Building B, 1015, Lausanne, Switzerland
| | - Felix Oden
- Life Molecular Imaging GmbH, Tegeler Strasse 6-7, 13353, Berlin, Germany
| | | | - David Hickman
- AC Immune SA, EPFL Innovation Park, Building B, 1015, Lausanne, Switzerland
| | - Ludger Dinkelborg
- Life Molecular Imaging GmbH, Tegeler Strasse 6-7, 13353, Berlin, Germany
| | - Andrew Stephens
- Life Molecular Imaging GmbH, Tegeler Strasse 6-7, 13353, Berlin, Germany
| | - Andrea Pfeifer
- AC Immune SA, EPFL Innovation Park, Building B, 1015, Lausanne, Switzerland
| | - Heiko Kroth
- AC Immune SA, EPFL Innovation Park, Building B, 1015, Lausanne, Switzerland.
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6
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White NA, Clagg K, Sirois LE, Lim NK, Nack WA, O’Shea PD, Zhang H, Gosselin F. Practical Synthesis of a Stable Precursor for Positron Emission Tomography Imaging Agent 18F-GTP1. Org Process Res Dev 2020. [DOI: 10.1021/acs.oprd.0c00301] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Nicholas A. White
- Department of Small Molecule Process Chemistry, Genentech, Inc., 1 DNA Way, South San Francisco, California 94080, United States
| | - Kyle Clagg
- Department of Small Molecule Process Chemistry, Genentech, Inc., 1 DNA Way, South San Francisco, California 94080, United States
| | - Lauren E. Sirois
- Department of Small Molecule Process Chemistry, Genentech, Inc., 1 DNA Way, South San Francisco, California 94080, United States
| | - Ngiap-Kie Lim
- Department of Small Molecule Process Chemistry, Genentech, Inc., 1 DNA Way, South San Francisco, California 94080, United States
| | - William A. Nack
- Exemplify BioPharma, 3000 Eastpark Boulevard, Suite 500-A, Cranbury, New Jersey 08512, United States
| | - Paul D. O’Shea
- Exemplify BioPharma, 3000 Eastpark Boulevard, Suite 500-A, Cranbury, New Jersey 08512, United States
| | - Haiming Zhang
- Department of Small Molecule Process Chemistry, Genentech, Inc., 1 DNA Way, South San Francisco, California 94080, United States
| | - Francis Gosselin
- Department of Small Molecule Process Chemistry, Genentech, Inc., 1 DNA Way, South San Francisco, California 94080, United States
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7
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White NA, Clagg K, Sirois LE, Mack KA, Al-Sayah MA, Nack WA, O'Shea PD, Zhang H, Gosselin F. Phosphoramidates as Steering Elements for Highly Selective Access to Complementary Imidazo[1,2- a]pyrimidine Isomers. Org Lett 2019; 21:9527-9531. [PMID: 31738563 DOI: 10.1021/acs.orglett.9b03702] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report that selective N-phosphorylation of aminoimidazoles results in a key steering element that controls isomeric selectivity in the condensation of β-ethoxy acrylamides and aminoimidazoles to furnish imidazo[1,2-a]pyrimidines. We identified conditions that provide highly selective (99:1) phosphorylation at the endo- or exocyclic nitrogen. Either the 2-amino or 4-amino isomer of the (benzo)imidazo[1,2-a]pyrimidine products could be isolated in 64-95% yield. Mass spectrometric analysis and computational studies give insight into the mechanism of this exceptionally selective transformation.
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Affiliation(s)
- Nicholas A White
- Department of Small Molecule Process Chemistry , Genentech, Inc. , 1 DNA Way , South San Francisco , California 94080 , United States
| | - Kyle Clagg
- Department of Small Molecule Process Chemistry , Genentech, Inc. , 1 DNA Way , South San Francisco , California 94080 , United States
| | - Lauren E Sirois
- Department of Small Molecule Process Chemistry , Genentech, Inc. , 1 DNA Way , South San Francisco , California 94080 , United States
| | - Kyle A Mack
- Department of Small Molecule Process Chemistry , Genentech, Inc. , 1 DNA Way , South San Francisco , California 94080 , United States
| | - Mohammad A Al-Sayah
- Department of Small Molecule Analytical Chemistry , Genentech, Inc. , 1 DNA Way , South San Francisco , California 94080 , United States
| | - William A Nack
- Exemplify BioPharma , 3000 Eastpark Boulevard, Suite 500-A , Cranbury , New Jersey 08512 , United States
| | - Paul D O'Shea
- Exemplify BioPharma , 3000 Eastpark Boulevard, Suite 500-A , Cranbury , New Jersey 08512 , United States
| | - Haiming Zhang
- Department of Small Molecule Process Chemistry , Genentech, Inc. , 1 DNA Way , South San Francisco , California 94080 , United States
| | - Francis Gosselin
- Department of Small Molecule Process Chemistry , Genentech, Inc. , 1 DNA Way , South San Francisco , California 94080 , United States
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8
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Kim DY, Quang Dao PD, Cho CS. Synthesis of Pyrimidine- and Quinazoline-Fused Benzimidazole-4,7-diones Using Combinatorial Cyclocondensation and Oxidation. ACS OMEGA 2018; 3:17456-17465. [PMID: 31458351 PMCID: PMC6643376 DOI: 10.1021/acsomega.8b02755] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Accepted: 11/20/2018] [Indexed: 05/27/2023]
Abstract
β-Bromo-α,β-unsaturated aldehydes and 2-bromobenzaldehydes react with 4,7-dimethoxy-1H-benzo[d]imidazole-2-amine by microwave irradiation in dimethylformamide in the presence of a base to give the corresponding dimethoxy-substituted benzo[4,5]imidazo[1,2-a]pyrimidines and benzo[4,5]imidazo[1,2-a]quinazolines, respectively, in moderate to good yields. Oxidation of such N-fused hybrid scaffolds by aqueous ceric ammonium nitrate affords pyrimidine- and quinazoline-fused benzimidazole-4,7-diones in high yields.
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9
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Dao PD, Lee HK, Sohn HS, Yoon NS, Cho CS. Synthesis of Benzo[4,5]imidazo[1,2- c]pyrimidin-1-amines and Their Analogs via Copper-Catalyzed C-N Coupling and Cyclization. ACS OMEGA 2017; 2:2953-2958. [PMID: 31457630 PMCID: PMC6640920 DOI: 10.1021/acsomega.7b00693] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2017] [Accepted: 06/12/2017] [Indexed: 05/05/2023]
Abstract
2-(2-Bromovinyl)benzimidazoles and 2-(2-bromophenyl)benzimidazoles react with cyanamide by microwave irradiation in dimethylformamide in the presence of a catalytic amount of CuI along with a base to give the corresponding benzo[4,5]imidazo[1,2-c]pyrimidin-1-amines and benzo[4,5]imidazo[1,2-c]quinazolin-6-amines, respectively, in moderate to good yields. 2-(2-Bromophenyl)indoles also react with cyanamide under similar conditions to afford indolo[1,2-c]quinazolin-6-amines. The reaction pathway seems to proceed via a sequence such as intermolecular C-N coupling, C-N formative cyclization, and tautomerization.
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Affiliation(s)
- Pham Duy
Quang Dao
- Department
of Applied Chemistry, Department of Materials Science and Metallurgical
Engineering, and Department of Textile System Engineering, Kyungpook National University, 80 Daehakro, Bukgu, Daegu 702-701, Republic of Korea
| | - Ha Kyeong Lee
- Department
of Applied Chemistry, Department of Materials Science and Metallurgical
Engineering, and Department of Textile System Engineering, Kyungpook National University, 80 Daehakro, Bukgu, Daegu 702-701, Republic of Korea
| | - Ho-Sang Sohn
- Department
of Applied Chemistry, Department of Materials Science and Metallurgical
Engineering, and Department of Textile System Engineering, Kyungpook National University, 80 Daehakro, Bukgu, Daegu 702-701, Republic of Korea
| | - Nam Sik Yoon
- Department
of Applied Chemistry, Department of Materials Science and Metallurgical
Engineering, and Department of Textile System Engineering, Kyungpook National University, 80 Daehakro, Bukgu, Daegu 702-701, Republic of Korea
| | - Chan Sik Cho
- Department
of Applied Chemistry, Department of Materials Science and Metallurgical
Engineering, and Department of Textile System Engineering, Kyungpook National University, 80 Daehakro, Bukgu, Daegu 702-701, Republic of Korea
- E-mail: (C.S.C.)
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10
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Gao M, Wang M, Zheng QH. Synthesis of [11C]MK-1064 as a new PET radioligand for imaging of orexin-2 receptor. Bioorg Med Chem Lett 2016; 26:3694-9. [DOI: 10.1016/j.bmcl.2016.05.083] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Revised: 05/23/2016] [Accepted: 05/27/2016] [Indexed: 12/29/2022]
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11
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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.
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12
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Dani M, Brooks DJ, Edison P. Tau imaging in neurodegenerative diseases. Eur J Nucl Med Mol Imaging 2015; 43:1139-50. [PMID: 26572762 PMCID: PMC4844651 DOI: 10.1007/s00259-015-3231-2] [Citation(s) in RCA: 90] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Accepted: 10/15/2015] [Indexed: 12/14/2022]
Abstract
Aggregated tau protein is a major neuropathological substrate central to the pathophysiology of neurodegenerative diseases such as Alzheimer's disease (AD), frontotemporal dementia, progressive supranuclear palsy, corticobasal degeneration and chronic traumatic encephalopathy. In AD, it has been shown that the density of hyperphosphorylated tau tangles correlates closely with neuronal dysfunction and cell death, unlike β-amyloid. Until now, diagnostic and pathologic information about tau deposition has only been available from invasive techniques such as brain biopsy or autopsy. The recent development of selective in-vivo tau PET imaging ligands including [(18)F]THK523, [(18)F]THK5117, [(18)F]THK5105 and [(18)F]THK5351, [(18)F]AV1451(T807) and [(11)C]PBB3 has provided information about the role of tau in the early phases of neurodegenerative diseases, and provided support for diagnosis, prognosis, and imaging biomarkers to track disease progression. Moreover, the spatial and longitudinal relationship of tau distribution compared with β - amyloid and other pathologies in these diseases can be mapped. In this review, we discuss the role of aggregated tau in tauopathies, the challenges posed in developing selective tau ligands as biomarkers, the state of development in tau tracers, and the new clinical information that has been uncovered, as well as the opportunities for improving diagnosis and designing clinical trials in the future.
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Affiliation(s)
- M Dani
- Neurology Imaging Unit, Division of Neuroscience, Imperial College London, 1st Floor, B Block, Hammersmith Hospital, Du Cane Road, London, W12 0NN, UK
| | - D J Brooks
- Neurology Imaging Unit, Division of Neuroscience, Imperial College London, 1st Floor, B Block, Hammersmith Hospital, Du Cane Road, London, W12 0NN, UK.,Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - P Edison
- Neurology Imaging Unit, Division of Neuroscience, Imperial College London, 1st Floor, B Block, Hammersmith Hospital, Du Cane Road, London, W12 0NN, UK.
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13
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Wang M, Gao M, Xu Z, Zheng QH. Synthesis of a PET tau tracer [(11)C]PBB3 for imaging of Alzheimer's disease. Bioorg Med Chem Lett 2015; 25:4587-92. [PMID: 26323870 DOI: 10.1016/j.bmcl.2015.08.053] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Revised: 08/17/2015] [Accepted: 08/20/2015] [Indexed: 11/17/2022]
Abstract
The authentic standard PBB3 and its precursor N-desmethyl-PBB3 as well as TBS-protected N-desmethyl-PBB3 precursor for radiolabeling were synthesized from 5-bromo-2-nitropyridine, acrolein diethyl acetal, 6-methoxy-2-methylbenzothiazole, and diethylchlorophosphate with overall chemical yield 1% in six steps, 2% in five steps, and 1% in six steps, respectively. [(11)C]PBB3 was prepared from either desmethyl-PBB3 or TBS-protected desmethyl-PBB3 with [(11)C]CH3OTf through N-[(11)C]methylation and isolated by HPLC combined with SPE in 20-25% and 15-20% radiochemical yield, respectively, based on [(11)C]CO2 and decay corrected to end of bombardment (EOB). The radiochemical purity was >99%, and the specific activity at EOB was 370-1110 GBq/μmol with a total synthesis time of ~40-min from EOB.
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Affiliation(s)
- Min Wang
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, 1345 West 16th Street, Room 202, Indianapolis, IN 46202, USA
| | - Mingzhang Gao
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, 1345 West 16th Street, Room 202, Indianapolis, IN 46202, USA
| | - Zhidong Xu
- Key Laboratory of Medicinal Chemistry and Molecular Diagnosis of Ministry of Education, College of Chemistry and Environmental Science, Hebei University, Baoding, Hebei 071002, China
| | - Qi-Huang Zheng
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, 1345 West 16th Street, Room 202, Indianapolis, IN 46202, USA.
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14
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Gao M, Wang M, Zheng QH. Fully automated synthesis of [18F]T807, a PET tau tracer for Alzheimer’s disease. Bioorg Med Chem Lett 2015; 25:2953-7. [DOI: 10.1016/j.bmcl.2015.05.035] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Revised: 05/12/2015] [Accepted: 05/13/2015] [Indexed: 01/14/2023]
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15
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Mouradzadegun A, Ma'mani L, Mahdavi M, Rashid Z, Shafiee A, Foroumadi A, Dianat S. Sulfamic acid-functionalized hydroxyapatite-encapsulated γ-Fe2O3 nanoparticles as a magnetically recoverable catalyst for synthesis of N-fused imidazole-quinoline conjugates under solvent-free conditions. RSC Adv 2015. [DOI: 10.1039/c5ra12307k] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
γ-Fe2O3-HAp-(CH2)3-NHSO3H was shown to be a powerful and reusable catalyst for the synthesis of N-fused imidazole-quinoline conjugates under solvent-free conditions.
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Affiliation(s)
- Arash Mouradzadegun
- Department of Chemistry
- Faculty of Sciences
- Shahid Chamran University
- Ahvaz
- Iran
| | - Leila Ma'mani
- Nanotechnology Department
- Agricultural Biotechnology Research Institute of Iran (ABRII)
- Karaj
- Iran
| | - Mohammad Mahdavi
- Department of Medical Chemistry
- Faculty of Pharmacy and Pharmaceutical Science Research Center
- Tehran University of Medical Sciences
- Tehran
- Iran
| | - Zahra Rashid
- Nanobiotechnology Research Center
- Avicenna Research Institute
- ACECR
- Tehran
- Iran
| | - Abbas Shafiee
- Department of Medical Chemistry
- Faculty of Pharmacy and Pharmaceutical Science Research Center
- Tehran University of Medical Sciences
- Tehran
- Iran
| | - Alireza Foroumadi
- Department of Medical Chemistry
- Faculty of Pharmacy and Pharmaceutical Science Research Center
- Tehran University of Medical Sciences
- Tehran
- Iran
| | - Shima Dianat
- Department of Chemistry
- Faculty of Sciences
- Shahid Chamran University
- Ahvaz
- Iran
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Gao M, Gao AC, Wang M, Zheng QH. Synthesis of carbon-11-labeled aminoalkylindole derivatives as new candidates of cannabinoid receptor radioligands for PET imaging of alcohol abuse. Bioorg Med Chem Lett 2014; 24:5581-5586. [DOI: 10.1016/j.bmcl.2014.10.097] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Revised: 10/28/2014] [Accepted: 10/30/2014] [Indexed: 11/30/2022]
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17
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Wang M, Gao M, Zheng QH. Synthesis of carbon-11-labeled 4-(phenylamino)-pyrrolo[2,1-f][1,2,4]triazine derivatives as new potential PET tracers for imaging of p38α mitogen-activated protein kinase. Bioorg Med Chem Lett 2014; 24:3700-5. [PMID: 25065491 DOI: 10.1016/j.bmcl.2014.07.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Revised: 07/04/2014] [Accepted: 07/07/2014] [Indexed: 12/30/2022]
Abstract
The reference standards methyl 4-(2-methyl-5-(methoxycarbamoyl)phenylamino)-5-methylpyrrolo[2,1-f][1,2,4]triazine-6-carboxylate (10a), methyl 4-(2-methyl-5-(ethoxycarbamoyl)phenylamino)-5-methylpyrrolo[2,1-f][1,2,4]triazine-6-carboxylate (10b) and corresponding precursors 4-(2-methyl-5-(methoxycarbamoyl)phenylamino)-5-methylpyrrolo[2,1-f][1,2,4]triazine-6-carboxylic acid (11a), methyl 4-(2-methyl-5-(ethoxycarbamoyl)phenylamino)-5-methylpyrrolo[2,1-f][1,2,4]triazine-6-carboxylic acid (11b) were synthesized from methyl crotonate and 3-amino-4-methylbenzoic acid in multiple steps with moderate to excellent yields. The target tracer [(11)C]methyl 4-(2-methyl-5-(methoxycarbamoyl)phenylamino)-5-methylpyrrolo[2,1-f][1,2,4]triazine-6-carboxylate ([(11)C]10a) and [(11)C]methyl 4-(2-methyl-5-(ethoxycarbamoyl)phenylamino)-5-methylpyrrolo[2,1-f][1,2,4]triazine-6-carboxylate ([(11)C]10b) were prepared from their corresponding precursors with [(11)C]CH3OTf under basic condition through O-[(11)C]methylation and isolated by a simplified solid-phase extraction (SPE) method in 50-60% radiochemical yields at end of bombardment (EOB) with 185-555 GBq/μmol specific activity at end of synthesis (EOS).
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Affiliation(s)
- Min Wang
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, 1345 West 16th Street, Room 202, Indianapolis, IN 46202, USA
| | - Mingzhang Gao
- 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.
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18
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Synthesis of a new fluorine-18-labeled bexarotene analogue for PET imaging of retinoid X receptor. Bioorg Med Chem Lett 2014; 24:1742-7. [DOI: 10.1016/j.bmcl.2014.02.037] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Revised: 02/10/2014] [Accepted: 02/13/2014] [Indexed: 11/20/2022]
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