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Fu C, He L, Xu H, Zhang Z, Chang X, Dang Y, Dong XQ, Wang CJ. Modular access to chiral bridged piperidine-γ-butyrolactones via catalytic asymmetric allylation/aza-Prins cyclization/lactonization sequences. Nat Commun 2024; 15:127. [PMID: 38167331 PMCID: PMC10762176 DOI: 10.1038/s41467-023-44336-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Accepted: 12/08/2023] [Indexed: 01/05/2024] Open
Abstract
Chiral functionalized piperidine and lactone heterocycles are widely spread in natural products and drug candidates with promising pharmacological properties. However, there remains no general asymmetric methodologies that enable rapid assemble both critical biologically important units into one three-dimensional chiral molecule. Herein, we describe a straightforward relay strategy for the construction of enantioenriched bridged piperidine-γ-butyrolactone skeletons incorporating three skipped stereocenters via asymmetric allylic alkylation and aza-Prins cyclization/lactonization sequences. The excellent enantioselectivity control in asymmetric allylation with the simplest allylic precursor is enabled by the synergistic Cu/Ir-catalyzed protocol; the success of aza-Prins cyclization/lactonization can be attributed to the pivotal role of the ester substituent, which acts as a preferential intramolecular nucleophile to terminate the aza-Prins intermediacy of piperid-4-yl cation species. The resulting chiral piperidine-γ-butyrolactone bridged-heterocyclic products show impressive preliminary biological activities against a panel of cancer cell lines.
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Affiliation(s)
- Cong Fu
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 430072, China
- State Key Laboratory of Elemento-organic Chemistry, Nankai University, Tianjin, 300071, China
| | - Ling He
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 430072, China
| | - Hui Xu
- Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, Tianjin University, Tianjin, 300072, China
| | - Zongpeng Zhang
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 430072, China
| | - Xin Chang
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 430072, China
| | - Yanfeng Dang
- Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, Tianjin University, Tianjin, 300072, China.
| | - Xiu-Qin Dong
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 430072, China.
| | - Chun-Jiang Wang
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 430072, China.
- State Key Laboratory of Elemento-organic Chemistry, Nankai University, Tianjin, 300071, China.
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2
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Ayre J, Redmond JM, Vitulli G, Tomlinson L, Weaver R, Comeo E, Bosquillon C, Stocks MJ. Design, Synthesis, and Evaluation of Lung-Retentive Prodrugs for Extending the Lung Tissue Retention of Inhaled Drugs. J Med Chem 2022; 65:9802-9818. [PMID: 35798565 PMCID: PMC9340777 DOI: 10.1021/acs.jmedchem.2c00416] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
A major limitation
of pulmonary delivery is that drugs can exhibit
suboptimal pharmacokinetic profiles resulting from rapid elimination
from the pulmonary tissue. This can lead to systemic side effects
and a short duration of action. A series of dibasic dipeptides attached
to the poorly lung-retentive muscarinic M3 receptor antagonist piperidin-4-yl
2-hydroxy-2,2-diphenylacetate (1) through a pH-sensitive-linking
group have been evaluated. Extensive optimization resulted in 1-(((R)-2-((S)-2,6-diaminohexanamido)-3,3-dimethylbutanoyl)oxy)ethyl
4-(2-hydroxy-2,2-diphenylacetoxy)piperidine-1-carboxylate (23), which combined very good in vitro stability and
very high rat lung binding. Compound 23 progressed to
pharmacokinetic studies in rats, where, at 24 h post dosing in the
rat lung, the total lung concentration of 23 was 31.2
μM. In addition, high levels of liberated drug 1 were still detected locally, demonstrating the benefit of this novel
prodrug approach for increasing the apparent pharmacokinetic half-life
of drugs in the lungs following pulmonary dosing.
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Affiliation(s)
- Jack Ayre
- School of Pharmacy, Biodiscovery Institute, University Park Nottingham, Nottingham NG7 2RD, U.K
| | - Joanna M Redmond
- GSK Medicines Research Centre, Gunnels Wood Road, Stevenage SG1 2NY, U.K
| | - Giovanni Vitulli
- GSK Medicines Research Centre, Gunnels Wood Road, Stevenage SG1 2NY, U.K
| | - Laura Tomlinson
- GSK Medicines Research Centre, Gunnels Wood Road, Stevenage SG1 2NY, U.K
| | - Richard Weaver
- XenoGesis Ltd, Discovery Building, BioCity, Pennyfoot Street, Nottingham NG1 1GR, U.K
| | - Eleonora Comeo
- School of Pharmacy, Biodiscovery Institute, University Park Nottingham, Nottingham NG7 2RD, U.K
| | - Cynthia Bosquillon
- School of Pharmacy, Boots Science Building, University Park Nottingham, Nottingham NG7 2RD, U.K
| | - Michael J Stocks
- School of Pharmacy, Biodiscovery Institute, University Park Nottingham, Nottingham NG7 2RD, U.K
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3
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Fujinaga M, Ohkubo T, Yamasaki T, Kumata K, Nengaki N, Zhang MR. Scandium Triflate-Catalyzed N-[ 18F]Fluoroalkylation of Aryl- Or Heteroaryl-Amines with [ 18F]Epifluorohydrin under Mild Conditions. Org Lett 2022; 24:4024-4028. [PMID: 35613453 DOI: 10.1021/acs.orglett.2c01459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The scandium triflate-catalyzed N-[18F]fluoroalkylation of aryl- or heteroaryl-amines with [18F]epifluorohydrin ([18F]2) was investigated. This reaction is mild and provides one-step access to N-[18F]fluoroalkylated aryl- or heteroaryl-amines, which are used for positron emission tomography imaging. The use of 2,2,2-trifluoroethanol as a cosolvent improved the reaction efficiency. The use of (S)- and (R)-[18F]2 produced the corresponding enantiomeric N-[18F]fluoroalkylated anilines.
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Affiliation(s)
- Masayuki Fujinaga
- Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, Chiba 263-8555, Japan
| | - Takayuki Ohkubo
- Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, Chiba 263-8555, Japan.,SHI Accelerator Service Ltd., 1-17-6 Osaki, Shinagawa-ku, Tokyo 141-0032, Japan
| | - Tomoteru Yamasaki
- Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, Chiba 263-8555, Japan
| | - Katsushi Kumata
- Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, Chiba 263-8555, Japan
| | - Nobuki Nengaki
- Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, Chiba 263-8555, Japan.,SHI Accelerator Service Ltd., 1-17-6 Osaki, Shinagawa-ku, Tokyo 141-0032, Japan
| | - Ming-Rong Zhang
- Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, Chiba 263-8555, Japan
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4
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Nallasivam JL, Fernandes RA. A Cascade Aza-Cope/Aza-Prins Cyclization Leading to Piperidine Derivatives. European J Org Chem 2015. [DOI: 10.1002/ejoc.201403607] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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5
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Hernández D, Boto A. Nucleoside Analogues: Synthesis and Biological Properties of Azanucleoside Derivatives. European J Org Chem 2014. [DOI: 10.1002/ejoc.201301731] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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6
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Wu J, Tang W, Pettman A, Xiao J. Efficient and Chemoselective Reduction of Pyridines to Tetrahydropyridines and PiperidinesviaRhodium-Catalyzed Transfer Hydrogenation. Adv Synth Catal 2012. [DOI: 10.1002/adsc.201201034] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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7
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Duan HF, Xie JH, Qiao XC, Wang LX, Zhou QL. Enantioselective Rhodium-Catalyzed Addition of Arylboronic Acids to α-Ketoesters. Angew Chem Int Ed Engl 2008; 47:4351-3. [PMID: 18442151 DOI: 10.1002/anie.200800423] [Citation(s) in RCA: 112] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Hai-Feng Duan
- State Key Laboratory and Institute of Elemento-organic Chemistry, Nankai University, Tianjin 300071, China
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8
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Duan HF, Xie JH, Qiao XC, Wang LX, Zhou QL. Enantioselective Rhodium-Catalyzed Addition of Arylboronic Acids to α-Ketoesters. Angew Chem Int Ed Engl 2008. [DOI: 10.1002/ange.200800423] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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9
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Prenant C, Gillies J, Bailey J, Chimon G, Smith N, Jayson GC, Zweit J. Synthesis of [18F]fluoroacetaldehyde. Application to [18F]fluoroethylation of benzylamine under reductive alkylation conditions. J Labelled Comp Radiopharm 2008. [DOI: 10.1002/jlcr.1514] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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10
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Li X, Jung YW, Snyder SE, Blair J, Sherman PS, Desmond T, Frey KA, Kilbourn MR. 5-tert-Butyl-2-(4'-[18F]fluoropropynylphenyl)-1,3-dithiane oxides: potential new GABA A receptor radioligands. Nucl Med Biol 2007; 35:549-59. [PMID: 18589299 DOI: 10.1016/j.nucmedbio.2007.08.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2007] [Revised: 08/01/2007] [Accepted: 08/16/2007] [Indexed: 10/22/2022]
Abstract
As potential new ligands targeting the binding site of gamma-aminobutyric acid (GABA) receptor ionophore, trans-5-tert-butyl-2-(4'-fluoropropynylphenyl)-2-methyl-1,1-dioxo-1,3-dithiane (1) and cis/trans-5-tert-butyl-2-(4'-fluoropropynylphenyl)-2-methyl-1,1,3,3-tetroxo-1,3-dithiane (2) were selected for radiolabeling and initial evaluation as in vivo imaging agents for positron emission tomography (PET). Both compounds exhibited identical high in vitro binding affinities (K(i)=6.5 nM). Appropriate tosylate-substituted ethynyl precursors were prepared by multistep syntheses involving stepwise sulfur oxidation and chromatographic isolation of desired trans isomers. Radiolabeling was accomplished in one step using nucleophilic [(18)F]fluorination. In vivo biodistribution studies with trans-[(18)F]1 and trans-[(18)F]2 showed significant initial uptake into mouse brain and gradual washout, with heterogeneous regional brain distributions and higher retention in the cerebral cortex and cerebellum and lower retention in the striatum and pons-medulla. These regional distributions of the new radioligands correlated with in vitro and ex vivo measures of standard radioligands binding to the ionophore- and benzodiazepine-binding sites of GABA(A) receptor in rodent brain. A comparison of these results with previously prepared radiotracers for other neurochemical targets, including successes and failures as in vivo radioligands, suggests that higher-affinity compounds with increased retention in target brain tissues will likely be needed before a successful radiopharmaceutical for human PET imaging can be identified.
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Affiliation(s)
- Xuehe Li
- Department of Radiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
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11
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Wadsak W, Mien LK, Ettlinger DE, Eidherr H, Haeusler D, Sindelar KM, Keppler BK, Dudczak R, Kletter K, Mitterhauser M. 18F fluoroethylations: different strategies for the rapid translation of 11C-methylated radiotracers. Nucl Med Biol 2007; 34:1019-28. [DOI: 10.1016/j.nucmedbio.2007.06.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2007] [Accepted: 06/25/2007] [Indexed: 10/22/2022]
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12
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Kilbourn MR, Ma B, Butch ER, Quesada C, Sherman PS. Anesthesia increases in vivo N-([18F]fluoroethyl)piperidinyl benzilate binding to the muscarinic cholinergic receptor. Nucl Med Biol 2007; 34:479-82. [PMID: 17591547 DOI: 10.1016/j.nucmedbio.2007.04.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2007] [Accepted: 04/14/2007] [Indexed: 11/30/2022]
Abstract
The in vivo binding of N-[18F]fluoroethyl-piperidinyl benzilate ([18F]FEPB) to the muscarinic cholinergic receptor was measured in awake and anesthetized rats. Studies were done using an equilibrium infusion technique to provide estimates of specific binding as distribution volume ratios. Anesthesia with either isoflurane or sodium pentobarbital produced a significant (65-90%) increase of radiotracer binding in receptor-rich brain regions (striatum, cortex, hippocampus) relative to awake controls. Pretreatment of anesthetized animals with the acetylcholinesterase inhibitor phenserine produced no further increases in radioligand binding, in contrast to the large (>70%) increases previously observed in awake animals following drug treatment. These studies demonstrate that anesthesia can produce significant changes in baseline biochemical measures that can obscure even very large effects of pharmacological challenges.
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Affiliation(s)
- Michael R Kilbourn
- Division of Nuclear Medicine, Department of Radiology, University of Michigan Medical School, Ann Arbor, MI 48109-0552, USA.
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13
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Kočalka P, Pohl R, Rejman D, Rosenberg I. Synthesis of racemic and enantiomeric 3-pyrrolidinyl derivatives of nucleobases. Tetrahedron 2006. [DOI: 10.1016/j.tet.2006.03.078] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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14
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Lin KS, Ding YS, Kim SW, Kil KE. Synthesis, enantiomeric resolution, F-18 labeling and biodistribution of reboxetine analogs: promising radioligands for imaging the norepinephrine transporter with positron emission tomography. Nucl Med Biol 2005; 32:415-22. [PMID: 15878511 DOI: 10.1016/j.nucmedbio.2005.02.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2004] [Revised: 02/15/2005] [Accepted: 02/15/2005] [Indexed: 01/06/2023]
Abstract
Racemic and enantiomerically pure ((S,S) and (R,R)) 2-[alpha-(2-(2-[(18)F]fluoroethoxy)phenoxy)benzyl]morpholine ([(18)F]FRB) and its tetradeuterated form [(18)F]FRB-D(4), analogs of the highly selective norepinephrine reuptake inhibitor reboxetine (2-[alpha-(2-ethoxyphenoxy)benzyl]morpholine, RB), have been synthesized for studies of norepinephrine transporter (NET) system with positron emission tomography (PET). The [(18)F]fluorinated precursor, (S,S)/(R,R)-N-tert-butyloxycarbonyl-2-[alpha-(2-hydroxyphenoxy)benzyl]morpholine ((S,S)/(R,R)-N-Boc-desethylRB), was prepared by the N-protection of (S,S)/(R,R)-2-[alpha-(2-hydroxyphenoxy)benzyl]morpholine ((S,S)/(R,R)-desethylRB) with a tert-butyloxycarbonyl (Boc) group followed by enantiomeric resolution with chiral HPLC to provide both (S,S) and (R,R) enantiomers with >99% enantiomeric purity. These compounds were then used for radiosynthesis to prepare enantiomerically pure [(18)F]FRB and [(18)F]FRB-D(4) via the following three-step procedure: (1) formation of 1-bromo-2-[(18)F]fluoroethane ([(18)F]BFE or [(18)F]BFE-D(4)) by nucleophilic displacement of 2-bromoethyl triflate (or D(4) analog) with no-carrier added [(18)F]F(-) in THF; (2) reaction of [(18)F]BFE (or [(18)F]BFE-D(4)) with N-Boc-desethylRB in DMF in the presence of excess base; and (3) deprotection with trifluoroacetic acid. The racemates, (S,S) and (R,R) enantiomers of [(18)F]FRB and [(18)F]FRB-D(4) were obtained in 11-27% (decay corrected to the end of bombardment, EOB) in 120-min synthesis time with a radiochemical purity of >98% and specific activities of 21-48 GBq/micromol (EOB). The results of the whole-body biodistribution studies with (S,S)-[(18)F]FRB-D(4) were similar to those with (S,S)-[(18)F]FRB but showed relatively faster blood clearance and no significant in vivo defluorination. Positron emission tomography studies in baboon brain also showed that (S,S)-[(18)F]FRB-D(4) may be a potentially useful ligand for imaging NET with PET.
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Affiliation(s)
- Kuo-Shyan Lin
- Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973, USA
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15
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Böhme TM, Keim C, Kreutzmann K, Linder M, Dingermann T, Dannhardt G, Mutschler E, Lambrecht G. Structure-activity relationships of dimethindene derivatives as new M2-selective muscarinic receptor antagonists. J Med Chem 2003; 46:856-67. [PMID: 12593665 DOI: 10.1021/jm020895l] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A series of 2,3-disubstituted indenes, which are analogues of the widely used histamine H(1) receptor antagonist dimethindene, have been synthesized and studied as muscarinic and histamine receptor antagonists. The affinities of these compounds for the five human muscarinic receptor subtypes (M(1)-M(5)) and for human histamine H(1) receptors were determined in radioligand binding studies using membranes from transfected Chinese hamster ovary (CHO) cells and [(3)H]N-methylscopolamine ([(3)H]NMS). The results demonstrate that the diisopropyl analogue 19 has a similar high affinity as (S)-dimethindene at M(2) receptors ((S)-dimethindene: pK(i) = 7.52; (-)-19: pK(i) = 7.37) with an improved selectivity pattern ((S)-dimethindene: M(2)/M(1) = 6-fold, M(2)/M(3) = 5-fold, M(2)/M(4) = 10-fold, M(2)/M(5) = 25-fold; (-)-19: M(2)/M(1) = 36-fold, M(2)/M(3) = 96-fold, M(2)/M(4) = 42-fold, M(2)/M(5) = 275-fold). In addition, compound (-)-19 showed 35-fold lower affinity at histamine H(1) receptors (pK(i) = 5.61) than (S)-dimethindene (pK(i) = 7.16). Another interesting compound is the fluoroethyl derivative 20 (pK(i)/M(2) = 7.49), which also exhibits a higher M(2) selectivity (M(2)/M(1) = 19-fold; M(2)/M(3) = 22-fold; M(2)/M(4) = 13-fold; M(2)/M(5) = 62-fold) than (S)-dimethindene. Unfortunately, compound 20 also shows a high affinity for histamine H(1) receptors (pK(i) = 8.14). The compound with the highest affinity for M(2) receptors (pK(i) = 7.91), the dimethylaminomethylene analogue 31, displayed only a small preference for M(2) receptors. In conclusion, compound (-)-19 might be useful to test the hypothesis that blockade of muscarinic M(2) receptors in the brain is a viable mechanism by which to produce improved cognition. This second-generation dimethindene analogue might also be the starting point for the development of M(2)-selective muscarinic antagonists useful for quantifying M(2) receptors in the central nervous system with positron emission tomography imaging.
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Affiliation(s)
- Thomas M Böhme
- Institute of Pharmacy, Johannes Gutenberg-University of Mainz, Staudinger Weg 5, D-55099 Mainz, Germany
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16
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Skaddan MB, Jewett DM, Sherman PS, Kilbourn MR. (R)-N-[11C]methyl-3-pyrrolidyl benzilate, a high-affinity reversible radioligand for PET studies of the muscarinic acetylcholine receptor. Synapse 2002; 45:31-7. [PMID: 12112411 DOI: 10.1002/syn.10079] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
We recently reported the synthesis and binding affinity of ligands for the muscarinic acetylcholine receptor (mAChR) based on both the pyrrolidyl and piperidyl benzilate scaffold. One of these, (R)-3-pyrrolidyl benzilate, was successfully radiolabeled with [(11)C]methyl triflate and the resulting compound, (R)-N-[(11)C]methyl-3-pyrrolidyl benzilate (3-[(11)C]NMPYB), was evaluated as a reversible, acetylcholine-sensitive tracer for the mAChR (K(i) of unlabeled 3-NMPYB is 0.72 nM). This compound displayed high, receptor-mediated retention in regions of the mouse and rat brain known to have high concentrations of mAChRs. Moreover, bolus studies in a pigtail monkey showed that this compound had superior clearance from the brain when compared to muscarinic radiotracers previously employed in human PET studies. Infusion studies in the same monkey revealed that it was possible to achieve equilibrium of radiotracer distribution for 3-[(11)C]NMPYB in both the striatum and cortex. Sensitivity to endogenous acetylcholine levels was evaluated by injecting phenserine (5 mg/kg) into rats prior to administration of 3-[(11)C]NMPYB in an equilibrium infusion protocol. This pretreatment produced a modest, statistically significant decrease (9-11%) in the distribution volume ratios for muscarinic receptor rich regions of the rat brain as compared to controls.
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Affiliation(s)
- Marc B Skaddan
- Department of Radiology, University of Michigan Medical School, Ann Arbor, Michigan 48109-0552, USA
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17
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Lasne MC, Perrio C, Rouden J, Barré L, Roeda D, Dolle F, Crouzel C. Chemistry of β +-Emitting Compounds Based on Fluorine-18. Top Curr Chem (Cham) 2002. [DOI: 10.1007/3-540-46009-8_7] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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18
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McPherson DW, Breeden WK, Beets AL, Luo H, Sood V, Knapp FF. Stereoselective synthesis, in vitro, and initial in vivo evaluation of 1-methylpiperidin-4-yl alpha-hydroxy-alpha-(1-iodo-1-propen-3-yl)-alpha-phenylacetate (IPIP): a novel radioiodinated molecular probe with high affinity for the muscarinic receptor. Nucl Med Biol 2001; 28:959-73. [PMID: 11711316 DOI: 10.1016/s0969-8051(01)00252-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
1-Methylpiperidin-4-yl alpha-hydroxy-alpha-(1-iodo-1-propen-3-yl)-alpha-phenylacetate (IPIP, Fig. 1) was investigated as a potential radioiodinated molecular probe targeted to the muscarinic receptor complex. The IPIP stereoisomers were synthesized via a chiral intermediate in >95% enantiomeric excess. The R-isomers demonstrated a M(1) to M(2) subtype selectivity of approximately 3 to 1 and the S-isomers demonstrated non-subtype selective binding in vitro. IPIP was radiolabeled with iodide-125 with an average radiochemical yield of 74.4% (+/-14.8, n = 5), specific activities >800 mCi/micromol, and radiochemical purities >97%. In vivo the Z-isomers demonstrated high uniform cerebral uptake suggesting non-subtype selective binding. In contrast, E-R-IPIP, after allowing a low uptake in M(2) rich areas to clear, demonstrated a retention of activity in M(1) and M(4) rich cerebral regions. In addition, the cerebral uptake of E-R-IPIP and Z-S-IPIP were inhibited by 70-90% via pretreatment with R-QNB, an established muscarinic antagonist. An ex vivo metabolism study demonstrated Z-S-IPIP was stable at the receptor site with an absence of radiolabeled metabolites.
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Affiliation(s)
- D W McPherson
- Nuclear Medicine Group, Life Sciences Division, Oak Ridge National Laboratory (ORNL), Post Office Box 2008, Building 4501, Oak Ridge, TN 37831-6229, USA.
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19
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Skaddan MB, Sherman PS, Kilbourn MR. The role of species-dependent metabolism in the regional brain retention of 18F-labeled muscarinic acetylcholine receptor ligands. Nucl Med Biol 2001; 28:753-9. [PMID: 11578895 DOI: 10.1016/s0969-8051(01)00240-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
We have developed PET radioligands for the muscarinic acetylcholine receptor designed to be sensitive to endogenous acetylcholine changes. These radioligands were based on the piperidyl and pyrrolidyl benzilate scaffold and include (R)-N-(2-[18F]fluoroethyl)-3-piperidyl benzilate (1b), (R)-N-(2-[18F]fluoroethyl)-3-pyrrolidyl benzilate (2b), and N-(2-[18F]fluoroethyl)-4-piperidyl benzilate (3b). In the mouse, intravenous injection of 2b produced a heterogeneous receptor-mediated regional retention of radioactivity, whereas in the rat a homogeneous brain distribution was observed. Analyses of blood and brain extracts showed a radiolabeled metabolite for 2b which was formed to a much greater extent in mice than rats. This metabolite may have a higher receptor binding affinity than authentic 2b, and thus be responsible for the apparent receptor-mediated binding in the mouse brain. Our findings emphasize the importance of metabolite analysis in multiple species when developing novel radiopharmaceuticals for in vivo use.
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Affiliation(s)
- M B Skaddan
- Department of Radiology, University of Michigan Medical School, B1G412 University Hospital, Ann Arbor, MI 48109-0552, USA
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Skaddan MB, Jewett DM, Kilbourn MR, Sherman PS. The synthesis, 11C-labeling, and biological evaluation of (R)-N-[11C]methyl-3-pyrrolidyl benzilate as an acetylcholine-sensitive ligand for the muscarinic acetylcholine receptor. J Labelled Comp Radiopharm 2001. [DOI: 10.1002/jlcr.2580440109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Skaddan MB, Kilbourn MR, Snyder SE, Sherman PS. Acetylcholinesterase inhibition increases in vivo N-(2-[18F]fluoroethyl)-4-piperidyl benzilate binding to muscarinic acetylcholine receptors. J Cereb Blood Flow Metab 2001; 21:144-8. [PMID: 11176279 DOI: 10.1097/00004647-200102000-00005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Although the inhibition of acetylcholinesterase remains the primary treatment of Alzheimer's disease, little is known of the results of increased acetylcholine levels on muscarinic receptor occupancy or function. Using N-(2-[18F]fluoroethyl)-4-piperidyl benzilate ([18F]FEPB), a moderate affinity (Ki = 1.7 nmol/L) nonsubtype-selective muscarinic receptor antagonist, the authors examined the sensitivity of equilibrium in vivo radioligand binding in rat brain with changes in endogenous acetylcholine levels produced by treatments with acetylcholinesterase inhibitors. Phenserine administration 30 minutes before resulted in a dose-dependent into muscarinic cholinergic receptors, reaching a maximum increase of 90% in the striatum at a dose of 5 mg/kg intraperitoneally. Constant infusion of physostigmine at a dosage of 250 microg/kg/min produced an identical increase in radioligand binding. This agonist-induced increase of in vivo mAChR radioligand binding offers a new method for monitoring of the efficacy of acetylcholinesterase inhibitors or other drugs to enhance acetylcholine actions at the muscarinic receptors.
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Affiliation(s)
- M B Skaddan
- Department of Radiology, University of Michigan Medical School, Ann Arbor 48109-0552, USA
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