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Ansari A, Gorde AB, Ramapanicker R. Asymmetric synthesis of six tetrahydroisoquinoline natural products through α-amination of an aldehyde. Tetrahedron 2021. [DOI: 10.1016/j.tet.2021.132121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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2
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Du Q, Liu L, Zhou T. General and Efficient Copper-Catalyzed Oxazaborolidine Complex in Transfer Hydrogenation of Isoquinolines under Mild Conditions. ACS OMEGA 2020; 5:21219-21225. [PMID: 32875258 PMCID: PMC7450644 DOI: 10.1021/acsomega.0c02957] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Accepted: 07/29/2020] [Indexed: 06/11/2023]
Abstract
A general and efficient method for copper-catalyzed transfer hydrogenation of isoquinolines with an oxazaborolidine-BH3 complex, under mild reaction conditions, is successfully developed. A broad range of isoquinolines has been reduced to the corresponding products with 61-85% yields. The method is applied to the synthesis of biologically active tetrahydrosioquinoline alkaloid (±)-norlaudanosine in 62% yield, which is the key precursor for the preparation of (±)-laudanosine, (±)-N-methyl-laudanosine, and (±)-xylopinine in one or two steps.
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Affiliation(s)
- Qianyu Du
- College
of Chemistry and Chemical Engineering, Southwest
Petroleum University, Xindu Road 8, Chengdu, Sichuan 610500, China
| | - Linpeng Liu
- College
of Chemistry and Chemical Engineering, Southwest
Petroleum University, Xindu Road 8, Chengdu, Sichuan 610500, China
| | - Taigang Zhou
- College
of Chemistry and Chemical Engineering, Southwest
Petroleum University, Xindu Road 8, Chengdu, Sichuan 610500, China
- State
Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Xindu Road 8, Chengdu, Sichuan 610500, China
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3
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Schönbauer D, Sambiagio C, Noël T, Schnürch M. Photocatalytic deaminative benzylation and alkylation of tetrahydroisoquinolines with N-alkylpyrydinium salts. Beilstein J Org Chem 2020; 16:809-817. [PMID: 32395184 PMCID: PMC7189001 DOI: 10.3762/bjoc.16.74] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Accepted: 04/04/2020] [Indexed: 11/23/2022] Open
Abstract
A ruthenium-catalyzed photoredox coupling of substituted N-aryltetrahydroisoquinolines (THIQs) and different bench-stable pyridinium salts was successfully developed to give fast access to 1-benzyl-THIQs. Furthermore, secondary alkyl and allyl groups were also successfully introduced via the same method. Additionally, the typically applied N-phenyl group in the THIQ substrate could be replaced by the cleavable p-methoxyphenyl (PMP) group and successful N-deprotection was demonstrated.
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Affiliation(s)
- David Schönbauer
- Institute of Applied Synthetic Chemistry, TU Wien, Getreidemarkt 9/163, 1060 Vienna, Austria
| | - Carlo Sambiagio
- Department of Chemical Engineering and Chemistry, Micro Flow Chemistry and Synthetic Methodology, Eindhoven University of Technology, Den Dolech 2, 5612 AZ Eindhoven, The Netherlands
| | - Timothy Noël
- Department of Chemical Engineering and Chemistry, Micro Flow Chemistry and Synthetic Methodology, Eindhoven University of Technology, Den Dolech 2, 5612 AZ Eindhoven, The Netherlands
| | - Michael Schnürch
- Institute of Applied Synthetic Chemistry, TU Wien, Getreidemarkt 9/163, 1060 Vienna, Austria
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4
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Puerto Galvis CE, Kouznetsov VV. Biomimetic Total Synthesis of Dysoxylum Alkaloids. J Org Chem 2019; 84:15294-15308. [PMID: 31689360 DOI: 10.1021/acs.joc.9b02093] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A five-step total synthesis of Dysoxylum alkaloids has been achieved using a biomimetic approach from zanthoxylamide protoalkaloids. The synthesis featured a direct amidation and a Bischler-Napieralski reaction to form the dihydroisoquinoline ring, which was then subjected to a Noyori asymmetric transfer hydrogenation to establish the stereogenic center at C-1. Our synthetic sequence provides an important perspective on the biosynthetic origin of Dysoxylum alkaloids, since 6 natural alkaloids and 12 synthetic analogues were obtained with high enantioselectivity and in overall yields up to 68%. In addition, we describe the acute toxicity toward zebrafish embryos of Dysoxylum alkaloids, comparing their toxicity with that of their corresponding zanthoxylamide protoalkaloids and establishing an enantioselectivity-toxicity relationship.
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Affiliation(s)
- Carlos E Puerto Galvis
- Laboratorio de Química Orgánica y Biomolecular, CMN , Universidad Industrial de Santander , Parque Tecnológico Guatiguará, Km 2 Vía Refugio , Piedecuesta 681011 , Colombia
| | - Vladimir V Kouznetsov
- Laboratorio de Química Orgánica y Biomolecular, CMN , Universidad Industrial de Santander , Parque Tecnológico Guatiguará, Km 2 Vía Refugio , Piedecuesta 681011 , Colombia
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Benmekhbi L, Louafi F, Roisnel T, Hurvois JP. Synthesis of Tetrahydroisoquinoline Alkaloids and Related Compounds through the Alkylation of Anodically Prepared α-Amino Nitriles. J Org Chem 2016; 81:6721-39. [PMID: 27410716 DOI: 10.1021/acs.joc.6b01419] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
α-Amino nitrile 2a was conveniently prepared in two individual steps from chiral hexafluorophosphate salt isoquinolinium (-)-8b including anodic cyanation as an efficient means to activate the sp(3) C1-H bond of the THIQ nucleus. The lithiation of 2a was carried out in THF at -80 °C in the presence of LDA to produce a stable α-amino carbanion which was condensed on a large variety of alkyl halides. The resulting quaternary α-amino nitriles were subjected to a stereoselective reductive decyanation in ethanol in the presence of NaBH4 as the hydride donor to yield N-Boc-1-alkyl-THIQs (+)-10a-g in up to 97:3 er's after removal of the chiral auxiliary group. Examination of the ORTEP view of THIQ (+)-1f revealed that the newly created stereogenic center had an absolute S configuration. Likewise, (-)-xylopinine was synthesized in four workup steps in an overall 63% yield from α-amino nitrile (+)-2b. In this process, crystallization of an enantioenriched mixture (90:10) of (-)-norlaudanosine with 1 equiv of (-)-N-acetyl-l-leucine afforded the leucinate salt (+)-13 (99:1 dr). Similarly, (+)-salsolidine was displaced from its (-)-DBTA salt (-)-12 in 99:1 er, which was determined by proton and carbon NMR spectroscopy in the presence of thiophosphinic acid (+)-14 as the chiral solvating agent.
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Affiliation(s)
- Lotfi Benmekhbi
- Laboratoire de Chimie des Matériaux, Faculté des Sciences Exactes, Université de Constantine 1 , route de Ain El Bey, 25000 Constantine, Algérie
| | - Fadila Louafi
- Unité de Recherche CHEMS, Faculté des Sciences Exactes, Université de Constantine 1 , route de Ain El Bey, 25000 Constantine, Algérie
| | - Thierry Roisnel
- Centre de Diffractométrie X, Institut des Sciences Chimiques de Rennes, UMR CNRS 6226, CNRS-Université de Rennes 1 , Bat. 10 B, Campus de Beaulieu, Avenue du Général Leclerc, 35042 Rennes Cedex, France
| | - Jean-Pierre Hurvois
- Institut des Sciences Chimiques de Rennes, UMR 6226, CNRS-Université de Rennes 1 , 2 Avenue Léon Bernard, 35043, Rennes Cedex, France
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Badarau E, Dilly S, Wouters J, Seutin V, Liégeois JF. Chemical modifications of the N -methyl-laudanosine scaffold point to new directions for SK channels exploration. Bioorg Med Chem Lett 2014; 24:5616-5620. [DOI: 10.1016/j.bmcl.2014.10.083] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Revised: 10/24/2014] [Accepted: 10/27/2014] [Indexed: 01/19/2023]
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Liégeois JF, Wouters J, Seutin V, Dilly S. Bis-(1,2,3,4-tetrahydroisoquinolinium): A Chiral Scaffold for Developing High-Affinity Ligands for SK Channels. ChemMedChem 2014; 9:737-40. [DOI: 10.1002/cmdc.201400028] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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Khorana N, Markmee S, Ingkaninan K, Ruchirawat S, Kitbunnadaj R, Pullagurla MR. Evaluation of a new lead for acetylcholinesterase inhibition. Med Chem Res 2008. [DOI: 10.1007/s00044-008-9122-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Bis-tetrahydroisoquinoline derivatives: AG525E1, a new step in the search for non-quaternary non-peptidic small conductance Ca2+-activated K+ channel blockers. Bioorg Med Chem Lett 2008; 18:3440-5. [DOI: 10.1016/j.bmcl.2008.03.069] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2008] [Revised: 03/21/2008] [Accepted: 03/25/2008] [Indexed: 11/22/2022]
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Facile synthesis of new carbon-11 labeled conformationally restricted rivastigmine analogues as potential PET agents for imaging AChE and BChE enzymes. Appl Radiat Isot 2008; 66:506-12. [DOI: 10.1016/j.apradiso.2007.11.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2007] [Revised: 10/11/2007] [Accepted: 11/13/2007] [Indexed: 11/22/2022]
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Gao M, Wang M, Zheng QH. Synthesis of carbon-11 labeled 1-(3,4-dimethoxybenzyl)-2,2-dimethyl-1,2,3,4-tetrahydroisoquinolinium derivatives as new potential PET SKCa channel imaging agents. Appl Radiat Isot 2008; 66:194-202. [PMID: 17905592 DOI: 10.1016/j.apradiso.2007.08.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2007] [Revised: 08/16/2007] [Accepted: 08/21/2007] [Indexed: 11/17/2022]
Abstract
Small conductance Ca2+-activated K+ (SKCa) channels play an important role in many functions such as neuronal communication and behavioral plasticity, secretion, and cell proliferation. SKCa channel modulation is associated with various brain, heart, and cancer diseases. N-methyl-laudanosine and its structurally related derivatives, substituted 1-(3,4-dimethoxybenzyl)-2,2-dimethyl-1,2,3,4-tetrahydroisoquinoliniums, are reversible and selective SKCa channel blockers. Carbon-11 labeled N-methyl-laudanosine and its tetrahydroisoquinolinium derivatives may serve as new probes for positron emission tomography (PET) to image SKCa channels in the brain, heart, and cancer. The key intermediates, substituted isoquinolines (3a-c), were synthesized using a modification of the Pomeranz-Fritsch procedure. The precursors, substituted 1-(3,4-dimethoxybenzyl)-2-methyl-1,2,3,4-tetrahydroisoquinolines (8a-c), and their corresponding reference standards, substituted 1-(3,4-dimethoxybenzyl)-2,2-dimethyl-1,2,3,4-tetrahydroisoquinoliniums (9a-c), were synthesized from compounds 3a-c with 3,4-dimethoxybenzyl chloride (2) in multiple steps with moderate to excellent chemical yields. The precursor 6,7-dimethoxy-1-(3,4-dimethoxybenzyl)-2-methyl-1,2,3,4-tetrahydroisoquinoline (10) was commercially available, and the methylation of compound 10 with methyl iodide provided N-methyl-laudanosine (11). The target quaternary ammonium tracers, carbon-11 labeled 1-(3,4-dimethoxybenzyl)-2,2-dimethyl-1,2,3,4-tetrahydroisoquinoliniums ([11C]9a-c and [11C]11), were prepared by N-[11C]methylation of the tertiary amine precursors (8a-c and 10) with [11C]methyl triflate and isolated by a simplified solid-phase extraction (SPE) purification using a SiO2 or cation-exchange CM Sep-Pak cartridge in 40-65% radiochemical yields.
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Affiliation(s)
- Mingzhang Gao
- Department of Radiology, Indiana University School of Medicine, 1345 West 16th Street, L-3 Room 202, Indianapolis, IN 46202, USA
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Graulich A, Dilly S, Farce A, Scuvée-Moreau J, Waroux O, Lamy C, Chavatte P, Seutin V, Liégeois JF. Synthesis and Radioligand Binding Studies of Bis-isoquinolinium Derivatives as Small Conductance Ca2+-Activated K+ Channel Blockers. J Med Chem 2007; 50:5070-5. [PMID: 17867663 DOI: 10.1021/jm070412j] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Starting from the scaffold of N-methyllaudanosine and N-methylnoscapine, which are known small conductance Ca2+-activated K+ channel blockers, original bis-isoquinolinium derivatives were synthezised and evaluated using binding studies, electrophysiology, and molecular modeling. These quaternary compounds are powerful blockers, and the most active ones have 10 times more affinity for the channels than dequalinium. The unsubstituted compounds possess a weaker affinity than the analogues having a 6,7-dimethoxy- or a 6,7,8-trimethoxy substitution. The length of the linker has no influence in the alkane derivatives. In relation to the xylene derivatives, the affinities are higher for the ortho and meta isomers. These results are well corroborated by a molecular modeling study. Finally, the most effective compounds have been tested in electrophysiological experiments on midbrain dopaminergic neurons and demonstrate the blocking potential of the apamin-sensitive after-hyperpolarization.
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Affiliation(s)
- Amaury Graulich
- Laboratory of Medicinal Chemistry, Drug Research Center, University of Liège, Avenue de l'Hôpital, 1 (B36), B-4000 Liège 1, Belgium.
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Fletcher DI, Ganellin CR, Piergentili A, Dunn PM, Jenkinson DH. Synthesis and pharmacological testing of polyaminoquinolines as blockers of the apamin-sensitive Ca2+-activated K+ channel (SK(Ca)). Bioorg Med Chem 2007; 15:5457-79. [PMID: 17560109 DOI: 10.1016/j.bmc.2007.05.054] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2006] [Revised: 05/19/2007] [Accepted: 05/23/2007] [Indexed: 11/29/2022]
Abstract
The synthesis and pharmacological testing of a series of non-peptidic blockers of the SK(Ca) (SK-3) channel is described. Target compounds were designed to mimic the spatial relationships of selected key residues in the energy-minimised structure of the octadecapeptide apamin, which are a highly potent blocker of this channel. Structures consist of a central unit, either a fumaric acid or an aromatic ring, to which are attached two alkylguanidine or two to four alkylaminoquinoline substituents. Potency was tested by the ability to inhibit the SK(Ca) channel-mediated after-hyperpolarization (AHP) in cultured rat sympathetic neurones. It was found that bis-aminoquinoline derivatives are significantly more potent as channel blockers than are the corresponding guanidines. This adds to the earlier evidence that delocalisation of positive charge through the more extensive aminoquinolinium ring system is important for effective channel binding. It was also found that an increase in activity can be gained by the addition of a third aminoquinoline residue to give non-quaternized amines which have submicromolar potencies (IC(50)=0.13-0.36 microM). Extension to four aminoquinoline residues increased the potency to IC(50)=93 nM.
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Affiliation(s)
- David I Fletcher
- Department of Chemistry, University College London, 20, Gordon Street, London WC1H 0AJ, UK
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Abstract
Small-conductance Ca(2+)-activated K(+) channels (SK channels) underlie the medium duration after hyperpolarization that follows single or trains of action potentials in many types of neurons. Three subtypes of SK subunits, SK1 (K(Ca)2.1), SK2 (K(Ca)2.2) and SK3 (K(Ca)2.3), have been cloned and are expressed differentially within the central nervous system (CNS). A paper in this issue of BJP reports the discovery of the first example of a positive modulator displaying not only selectivity for SK channels over other channels, but also a subtype selectivity among SK and analogous channels (SK3>SK2>>>SK1=IK). Together with other recent progress in the field, this finding enriches the repertoire of tools available to test the hypothesis that SK channels may be targets for future CNS drugs.
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Affiliation(s)
- V Seutin
- Laboratory of Pharmacology and Research Center for Cellular and Molecular Neurobiology, University of Liège, Liège, Belgium.
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