1
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Wang D, Jiang W, Churiwal M, Jia K, Senadeera SPD, Bokesch HR, Woldemichael GM, Kim Y, Hawley RG, Wei JS, Khan J, O'Keefe BR, Beutler JA, Gustafson KR. Neopetrotaurines A-C, Isoquinoline Alkaloids with an Unprecedented Taurine Bridge from the Sponge Neopetrosia sp. JOURNAL OF NATURAL PRODUCTS 2024; 87:332-339. [PMID: 38294825 DOI: 10.1021/acs.jnatprod.3c01041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
Neopetrotaurines A-C (1-3), unusual alkaloids possessing two isoquinoline-derived moieties that are linked via a unique taurine bridge, were isolated from a Neopetrosia sp. marine sponge. These new compounds have proton-deficient structural scaffolds that are difficult to unambiguously assign using only conventional 2- and 3-bond 1H-13C and 1H-15N heteronuclear correlation data. Thus, the application of LR-HSQMBC and HMBC NMR experiments optimized to detect 4- and 5-bond long-range 1H-13C heteronuclear correlations facilitated the structure elucidation of these unusual taurine-bridged marine metabolites. Neopetrotaurines A-C (1-3) showed significant inhibition of transcription driven by the oncogenic fusion protein PAX3-FOXO1, which is associated with alveolar rhabdomyosarcoma, and cytotoxic activity against PAX3-FOXO1-positive cell lines.
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Affiliation(s)
- Dongdong Wang
- Molecular Targets Program, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702-1201, United States
| | - Wei Jiang
- Molecular Targets Program, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702-1201, United States
- Marine Science & Technology Institute, College of Environmental Science & Engineering, Yangzhou University, Yangzhou, Jiangsu 225127, People's Republic of China
| | - Mehal Churiwal
- Genetics Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland 20892, United States
| | - Katrina Jia
- Genetics Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland 20892, United States
| | - Sarath P D Senadeera
- Molecular Targets Program, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702-1201, United States
| | - Heidi R Bokesch
- Molecular Targets Program, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702-1201, United States
- Basic Science Program, Leidos Biomedical Research, Incorporated, Frederick National Laboratory for Cancer Research, Frederick, Maryland 21702-1201, United States
| | - Girma M Woldemichael
- Marine Science & Technology Institute, College of Environmental Science & Engineering, Yangzhou University, Yangzhou, Jiangsu 225127, People's Republic of China
- Basic Science Program, Leidos Biomedical Research, Incorporated, Frederick National Laboratory for Cancer Research, Frederick, Maryland 21702-1201, United States
| | - Yong Kim
- Genetics Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland 20892, United States
| | - Robert G Hawley
- Genetics Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland 20892, United States
| | - Jun S Wei
- Genetics Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland 20892, United States
| | - Javed Khan
- Genetics Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland 20892, United States
| | - Barry R O'Keefe
- Molecular Targets Program, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702-1201, United States
- Natural Products Branch, Developmental Therapeutics Program, Division of Cancer Treatment and Diagnosis, National Cancer Institute, Frederick, Maryland 21702-1201, United States
| | - John A Beutler
- Molecular Targets Program, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702-1201, United States
| | - Kirk R Gustafson
- Molecular Targets Program, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702-1201, United States
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2
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Zheng JY, Luo Y, Ou TT, Zhang XJ, Lao YQ, Feng N, Peng JB, Zhang XZ, Yao X, Ma AJ. Acid-Promoted Cyclization of α-Azidobenzyl Ketones through C═N Bond Formation: Synthesis of 6-Substituted Quinoline Derivatives. Org Lett 2024; 26:586-590. [PMID: 38198745 DOI: 10.1021/acs.orglett.3c03697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2024]
Abstract
An acid-promoted cyclization of α-azidobenzyl ketones has been developed for the synthesis of 6-substituted quinoline derivatives. A variety of synthetically useful 6-OTf or -OMs quinoline derivatives were obtained in moderate to good yields. The reaction proceeds via C═N bond formation without organophosphine, providing convenient access to structurally interesting and synthetically important 6-substituted quinoline derivatives in moderate to good yields. A mechanistic perspective that is different from the traditional intramolecular Schmidt reaction has been proposed.
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Affiliation(s)
- Jing-Yun Zheng
- School of Biotechnology and Health Sciences, Wuyi University, Jiangmen, Guangdong 529020, China
| | - Ying Luo
- School of Biotechnology and Health Sciences, Wuyi University, Jiangmen, Guangdong 529020, China
| | - Ting-Ting Ou
- School of Biotechnology and Health Sciences, Wuyi University, Jiangmen, Guangdong 529020, China
| | - Xin-Jie Zhang
- School of Biotechnology and Health Sciences, Wuyi University, Jiangmen, Guangdong 529020, China
| | - Yong-Qiang Lao
- School of Biotechnology and Health Sciences, Wuyi University, Jiangmen, Guangdong 529020, China
| | - Na Feng
- School of Biotechnology and Health Sciences, Wuyi University, Jiangmen, Guangdong 529020, China
| | - Jin-Bao Peng
- School of Biotechnology and Health Sciences, Wuyi University, Jiangmen, Guangdong 529020, China
| | - Xiang-Zhi Zhang
- School of Biotechnology and Health Sciences, Wuyi University, Jiangmen, Guangdong 529020, China
| | - Xiaojun Yao
- Centre for Artificial Intelligence Driven Drug Discovery, Faculty of Applied Sciences, Macao Polytechnic University, Macao 999078, China
| | - Ai-Jun Ma
- School of Biotechnology and Health Sciences, Wuyi University, Jiangmen, Guangdong 529020, China
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3
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Mullowney MW, Duncan KR, Elsayed SS, Garg N, van der Hooft JJJ, Martin NI, Meijer D, Terlouw BR, Biermann F, Blin K, Durairaj J, Gorostiola González M, Helfrich EJN, Huber F, Leopold-Messer S, Rajan K, de Rond T, van Santen JA, Sorokina M, Balunas MJ, Beniddir MA, van Bergeijk DA, Carroll LM, Clark CM, Clevert DA, Dejong CA, Du C, Ferrinho S, Grisoni F, Hofstetter A, Jespers W, Kalinina OV, Kautsar SA, Kim H, Leao TF, Masschelein J, Rees ER, Reher R, Reker D, Schwaller P, Segler M, Skinnider MA, Walker AS, Willighagen EL, Zdrazil B, Ziemert N, Goss RJM, Guyomard P, Volkamer A, Gerwick WH, Kim HU, Müller R, van Wezel GP, van Westen GJP, Hirsch AKH, Linington RG, Robinson SL, Medema MH. Artificial intelligence for natural product drug discovery. Nat Rev Drug Discov 2023; 22:895-916. [PMID: 37697042 DOI: 10.1038/s41573-023-00774-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/20/2023] [Indexed: 09/13/2023]
Abstract
Developments in computational omics technologies have provided new means to access the hidden diversity of natural products, unearthing new potential for drug discovery. In parallel, artificial intelligence approaches such as machine learning have led to exciting developments in the computational drug design field, facilitating biological activity prediction and de novo drug design for molecular targets of interest. Here, we describe current and future synergies between these developments to effectively identify drug candidates from the plethora of molecules produced by nature. We also discuss how to address key challenges in realizing the potential of these synergies, such as the need for high-quality datasets to train deep learning algorithms and appropriate strategies for algorithm validation.
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Affiliation(s)
| | - Katherine R Duncan
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK
| | - Somayah S Elsayed
- Department of Molecular Biotechnology, Institute of Biology, Leiden University, Leiden, The Netherlands
| | - Neha Garg
- School of Chemistry and Biochemistry, Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, GA, USA
| | - Justin J J van der Hooft
- Bioinformatics Group, Wageningen University, Wageningen, The Netherlands
- Department of Biochemistry, University of Johannesburg, Johannesburg, South Africa
| | - Nathaniel I Martin
- Biological Chemistry Group, Institute of Biology, Leiden University, Leiden, The Netherlands
| | - David Meijer
- Bioinformatics Group, Wageningen University, Wageningen, The Netherlands
| | - Barbara R Terlouw
- Bioinformatics Group, Wageningen University, Wageningen, The Netherlands
| | - Friederike Biermann
- Bioinformatics Group, Wageningen University, Wageningen, The Netherlands
- Institute of Molecular Bio Science, Goethe-University Frankfurt, Frankfurt am Main, Germany
- LOEWE Center for Translational Biodiversity Genomics (TBG), Frankfurt am Main, Germany
| | - Kai Blin
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kongens Lyngby, Denmark
| | | | - Marina Gorostiola González
- Drug Discovery and Safety, Leiden Academic Centre for Drug Research, Leiden, The Netherlands
- ONCODE institute, Leiden, The Netherlands
| | - Eric J N Helfrich
- Institute of Molecular Bio Science, Goethe-University Frankfurt, Frankfurt am Main, Germany
- LOEWE Center for Translational Biodiversity Genomics (TBG), Frankfurt am Main, Germany
| | - Florian Huber
- Center for Digitalization and Digitality, Hochschule Düsseldorf, Düsseldorf, Germany
| | - Stefan Leopold-Messer
- Institut für Mikrobiologie, Eidgenössische Technische Hochschule (ETH) Zürich, Zürich, Switzerland
| | - Kohulan Rajan
- Institute for Inorganic and Analytical Chemistry, Friedrich-Schiller-University Jena, Jena, Germany
| | - Tristan de Rond
- School of Chemical Sciences, University of Auckland, Auckland, New Zealand
| | - Jeffrey A van Santen
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Maria Sorokina
- Institute for Inorganic and Analytical Chemistry, Friedrich-Schiller University, Jena, Germany
- Pharmaceuticals R&D, Bayer AG, Berlin, Germany
| | - Marcy J Balunas
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA
- Department of Medicinal Chemistry, University of Michigan, Ann Arbor, MI, USA
| | - Mehdi A Beniddir
- Équipe "Chimie des Substances Naturelles", Université Paris-Saclay, CNRS, BioCIS, Orsay, France
| | - Doris A van Bergeijk
- Department of Molecular Biotechnology, Institute of Biology, Leiden University, Leiden, The Netherlands
| | - Laura M Carroll
- Structural and Computational Biology Unit, EMBL, Heidelberg, Germany
| | - Chase M Clark
- Division of Pharmaceutical Sciences, School of Pharmacy, University of Wisconsin-Madison, Madison, WI, USA
| | | | | | - Chao Du
- Department of Molecular Biotechnology, Institute of Biology, Leiden University, Leiden, The Netherlands
| | | | - Francesca Grisoni
- Institute for Complex Molecular Systems, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
- Centre for Living Technologies, Alliance TU/e, WUR, UU, UMC Utrecht, Utrecht, The Netherlands
| | | | - Willem Jespers
- Drug Discovery and Safety, Leiden Academic Centre for Drug Research, Leiden, The Netherlands
| | - Olga V Kalinina
- Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI), Saarbrücken, Germany
- Drug Bioinformatics, Medical Faculty, Saarland University, Homburg, Germany
- Center for Bioinformatics, Saarland University, Saarbrücken, Germany
| | | | - Hyunwoo Kim
- College of Pharmacy and Integrated Research Institute for Drug Development, Dongguk University Seoul, Goyang-si, Republic of Korea
| | - Tiago F Leao
- Center for Nuclear Energy in Agriculture, University of São Paulo, Piracicaba, Brazil
| | - Joleen Masschelein
- Center for Microbiology, VIB-KU Leuven, Heverlee, Belgium
- Department of Biology, KU Leuven, Heverlee, Belgium
| | - Evan R Rees
- Division of Pharmaceutical Sciences, School of Pharmacy, University of Wisconsin-Madison, Madison, WI, USA
| | - Raphael Reher
- Institute of Pharmaceutical Biology and Biotechnology, University of Marburg, Marburg, Germany
- Institute of Pharmacy, Martin-Luther-University Halle-Wittenberg, Halle (Saale), Germany
| | - Daniel Reker
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
- Duke Microbiome Center, Duke University, Durham, NC, USA
| | - Philippe Schwaller
- Laboratory of Artificial Chemical Intelligence, Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | | | - Michael A Skinnider
- Adapsyn Bioscience, Hamilton, Ontario, Canada
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada
| | - Allison S Walker
- Department of Chemistry, Vanderbilt University, Nashville, TN, USA
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Egon L Willighagen
- Department of Bioinformatics - BiGCaT, NUTRIM, Maastricht University, Maastricht, The Netherlands
| | - Barbara Zdrazil
- European Bioinformatics Institute (EMBL-EBI), Wellcome Genome Campus, Cambridgeshire, UK
| | - Nadine Ziemert
- Interfaculty Institute for Microbiology and Infection Medicine Tuebingen (IMIT), Institute for Bioinformatics and Medical Informatics (IBMI), University of Tuebingen, Tuebingen, Germany
| | | | - Pierre Guyomard
- Bonsai team, CRIStAL - Centre de Recherche en Informatique Signal et Automatique de Lille, Université de Lille, Villeneuve d'Ascq Cedex, France
| | - Andrea Volkamer
- Center for Bioinformatics, Saarland University, Saarbrücken, Germany
- In silico Toxicology and Structural Bioinformatics, Institute of Physiology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - William H Gerwick
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, USA
| | - Hyun Uk Kim
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea
| | - Rolf Müller
- Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI), Saarbrücken, Germany
- Department of Pharmacy, Saarland University, Saarbrücken, Germany
- German Center for infection research (DZIF), Braunschweig, Germany
- Helmholtz International Lab for Anti-Infectives, Saarbrücken, Germany
| | - Gilles P van Wezel
- Department of Molecular Biotechnology, Institute of Biology, Leiden University, Leiden, The Netherlands
- Netherlands Institute of Ecology, NIOO-KNAW, Wageningen, The Netherlands
| | - Gerard J P van Westen
- Drug Discovery and Safety, Leiden Academic Centre for Drug Research, Leiden, The Netherlands.
| | - Anna K H Hirsch
- Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI), Saarbrücken, Germany.
- Department of Pharmacy, Saarland University, Saarbrücken, Germany.
- German Center for infection research (DZIF), Braunschweig, Germany.
- Helmholtz International Lab for Anti-Infectives, Saarbrücken, Germany.
| | - Roger G Linington
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia, Canada.
| | - Serina L Robinson
- Department of Environmental Microbiology, Eawag: Swiss Federal Institute for Aquatic Science and Technology, Dübendorf, Switzerland.
| | - Marnix H Medema
- Bioinformatics Group, Wageningen University, Wageningen, The Netherlands.
- Institute of Biology, Leiden University, Leiden, The Netherlands.
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4
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Yu H, Zhang J, Ma D, Li X, Xu T. Enantioselective Total Syntheses of (-)-Caulamidine D and (-)-Isocaulamidine D and Their Absolute Configuration Reassignment. J Am Chem Soc 2023; 145:22335-22340. [PMID: 37792337 DOI: 10.1021/jacs.3c08714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
The first enantioselective total syntheses of (-)-caulamidine D (5) and (-)-isocaulamidine D (6) were accomplished. Their absolute configurations were unambiguously elucidated through X-ray crystallography. The isolated natural samples of both 5 and 6 are determined to be the TFA salts instead of the neutral forms. It took 16 steps (longest linear sequence) to divergently access both 5 and 6 following a unified strategy. The key reactions include (1) development and application of an asymmetric Meerwein-Eschenmoser-Claisen rearrangement to construct the challenging C10, C23 consecutive stereocenters and (2) application of a cascade 6-exo-dig/6-exo-tet amine/nitrile cyclization reaction.
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Affiliation(s)
- Haiyong Yu
- Molecular Synthesis Center and Key Laboratory of Marine Drugs, MOE, and School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China
| | - Junhao Zhang
- Molecular Synthesis Center and Key Laboratory of Marine Drugs, MOE, and School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China
| | - Dongxu Ma
- Molecular Synthesis Center and Key Laboratory of Marine Drugs, MOE, and School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China
| | - Xiaotong Li
- Molecular Synthesis Center and Key Laboratory of Marine Drugs, MOE, and School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China
| | - Tao Xu
- Molecular Synthesis Center and Key Laboratory of Marine Drugs, MOE, and School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China
- Laboratory for Marine Drugs and Bioproducts of Marine Natural Products, Laoshan Lab, Qingdao 266237, China
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5
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Silva Elipe MV, Ndukwe IE, Navarro-Vázquez A. Anisotropic NMR data acquisition with a prototype 400 MHz cryogen-free NMR spectrometer. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2023; 61:530-543. [PMID: 37530063 DOI: 10.1002/mrc.5380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 06/22/2023] [Accepted: 06/26/2023] [Indexed: 08/03/2023]
Abstract
High-temperature superconducting (HTS) materials have recently been incorporated into the construction of HTS cryogen-free magnets for nuclear magnetic resonance (NMR) spectroscopy. These HTS NMR spectrometers do not require liquid cryogens, thereby providing significant cost savings and facilitating easy integration into chemistry laboratories. However, the optimal performance of these HTS magnets against standard cryogen NMR magnets must be evaluated, especially with demanding modern NMR applications such as NMR in anisotropic media. The stability of the HTS magnets over time and their performance with complex pulse sequence experiments are the main unknown factors of this new technology. In this study, we evaluate the utility of our prototype 400 MHz cryogen-free power-driven HTS NMR spectrometer, installed in the fumehood of a chemistry laboratory, for stereochemical analysis of three commercial natural products (artemisinin, artemether, and dihydroartemisinin) via measurement of anisotropic NMR data, in particular, residual dipolar couplings. The accuracy of measurement of the anisotropic NMR data with the HTS magnet spectrometer is evaluated through the CASE-3D fitting protocol, as implemented in the Mestrenova-StereoFitter software program.
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Affiliation(s)
| | | | - Armando Navarro-Vázquez
- Departmento de Química Fundamental, Centro de Ciências Exatas e da Natureza, Universidade Federal de Pernambuco, Recife, Pernambuco, Brazil
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6
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Tian X, Wang D, Jiang W, Bokesch HR, Wilson BAP, O'Keefe BR, Gustafson KR. Rare Caulamidine Hexacyclic Alkaloids from the Marine Ascidian Polyandrocarpa sp. JOURNAL OF NATURAL PRODUCTS 2023; 86:1855-1861. [PMID: 37368408 PMCID: PMC10732314 DOI: 10.1021/acs.jnatprod.3c00393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/28/2023]
Abstract
Two new caulamidines C (2) and D (4) and three isocaulamidines B, C, and D (1, 3, and 5) along with the known compound caulamidine B (6) were isolated from the marine ascidian Polyandrocarpa sp. Their structures were elucidated by analysis of nuclear magnetic resonance (NMR) and electronic circular dichroism (ECD) data. Isocaulamidines have an altered pattern of N-methyl substitution (N-15 vs N-13 in the caulamidines) with a concomitant double-bond rearrangement to provide a new C-14/N-13 imine functionality. Caulamidine C (2) and isocaulamidine C (3) are the first members of this alkaloid family with two chlorine substituents in the core 6H-2,6-naphthyridine ring system.
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Affiliation(s)
- Xiangrong Tian
- College of Forestry, Northwest A&F University, Yangling, Shaanxi 712100, People's Republic of China
- Molecular Targets Program, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702-1201, United States
| | - Dongdong Wang
- Molecular Targets Program, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702-1201, United States
| | - Wei Jiang
- Molecular Targets Program, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702-1201, United States
- Marine Science & Technology Institute, College of Environmental Science & Engineering, Yangzhou University, Yangzhou, Jiangsu 225127, People's Republic of China
| | - Heidi R Bokesch
- Molecular Targets Program, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702-1201, United States
- Basic Science Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland 21702-1201, United States
| | - Brice A P Wilson
- Molecular Targets Program, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702-1201, United States
| | - Barry R O'Keefe
- Molecular Targets Program, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702-1201, United States
- Natural Products Branch, Development Therapeutics Program, Division of Cancer Treatment and Diagnosis, National Cancer Institute, Frederick, Maryland 21702-1201, United States
| | - Kirk R Gustafson
- Molecular Targets Program, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702-1201, United States
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7
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Crouch RC, Pelmuş M, Raab JG, Tischenko E, Frey M, Wang Y, Reibarkh M, Williamson RT, Martin GE. J-modulated 19 F- and 1 H-detected dual-optimized inverted 1 J CC 1,n-ADEQUATE: A universal ADEQUATE experiment. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2023; 61:169-179. [PMID: 36349476 DOI: 10.1002/mrc.5324] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 11/04/2022] [Accepted: 11/07/2022] [Indexed: 06/16/2023]
Abstract
The recently reported 19 F-detected dual-optimized inverted 1 JCC 1,n-ADEQUATE experiment and the previously reported 1 H-detected version have been modified to incorporate J-modulation, making it feasible to acquire all 1,1- and 1,n-ADEQUATE correlations as well as 1 JCC and n JCC homonuclear scalar couplings in a single experiment. The experiments are demonstrated using N,N-dimethylamino-2,5,6-trifluoro-3,4-phthalonitrile and N,N-dimethylamino-3,4-phthalonitrile.
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Affiliation(s)
- Ronald C Crouch
- Analytical Instruments, JEOL USA Inc., Peabody, Massachusetts, USA
| | - Marius Pelmuş
- Department of Chemistry, Seton Hall University, South Orange, New Jersey, USA
| | - Jeffrey G Raab
- Department of Chemistry and Biochemistry, University of North Carolina Wilmington, Wilmington, North Carolina, USA
- Department of Chemistry and Chemical Biology, Stevens Institute of Technology, Hoboken, New Jersey, USA
| | - Evgeny Tischenko
- Analytical Instruments, JEOL USA Inc., Peabody, Massachusetts, USA
| | - Michael Frey
- Analytical Instruments, JEOL USA Inc., Peabody, Massachusetts, USA
| | - Yunyi Wang
- Analytical Research and Development, Merck and Co., Inc., Rahway, New Jersey, USA
| | - Mikhail Reibarkh
- Analytical Research and Development, Merck and Co., Inc., Rahway, New Jersey, USA
| | - R Thomas Williamson
- Department of Chemistry and Biochemistry, University of North Carolina Wilmington, Wilmington, North Carolina, USA
| | - Gary E Martin
- Department of Chemistry, Seton Hall University, South Orange, New Jersey, USA
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8
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Gribble GW. Naturally Occurring Organohalogen Compounds-A Comprehensive Review. PROGRESS IN THE CHEMISTRY OF ORGANIC NATURAL PRODUCTS 2023; 121:1-546. [PMID: 37488466 DOI: 10.1007/978-3-031-26629-4_1] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/26/2023]
Abstract
The present volume is the third in a trilogy that documents naturally occurring organohalogen compounds, bringing the total number-from fewer than 25 in 1968-to approximately 8000 compounds to date. Nearly all of these natural products contain chlorine or bromine, with a few containing iodine and, fewer still, fluorine. Produced by ubiquitous marine (algae, sponges, corals, bryozoa, nudibranchs, fungi, bacteria) and terrestrial organisms (plants, fungi, bacteria, insects, higher animals) and universal abiotic processes (volcanos, forest fires, geothermal events), organohalogens pervade the global ecosystem. Newly identified extraterrestrial sources are also documented. In addition to chemical structures, biological activity, biohalogenation, biodegradation, natural function, and future outlook are presented.
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Affiliation(s)
- Gordon W Gribble
- Department of Chemistry, Dartmouth College, Hanover, NH, 03755, USA.
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9
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Immel S, Köck M, Reggelin M. NMR-Based Configurational Assignments of Natural Products: How Floating Chirality Distance Geometry Calculations Simplify Gambling with 2 N-1 Diastereomers. JOURNAL OF NATURAL PRODUCTS 2022; 85:1837-1849. [PMID: 35820115 DOI: 10.1021/acs.jnatprod.2c00427] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Using NMR data, the assignment of the correct 3D configuration and conformation to unknown natural products is of pivotal importance in pharmaceutical and medicinal chemistry. In this report, we quantify the probability of configurational assignments to judge the quality of structural elucidations using Bayesian inference in combination with floating-chirality distance geometry simulations. Based on reference-free NOE/ROE data, residual dipolar couplings (RDCs), and residual quadrupolar couplings (RQCs) in various combinations, we demonstrate how the relative configurations of three natural compounds, namely, jatrohemiketal (1), artemisinin (2), and Taxol (3), can be unambiguously established without the necessity to carry out time-consuming DFT-based configurational and conformational analyses. Our results quantitatively describe how reliably molecular geometries can be inferred from experimental NMR data, thereby unequivocally unveiling remaining assignment ambiguities. The methodology presented here will dramatically reduce the risk of incorrect structural assignments based on the overinterpretation of incomplete data and DFT-based structure models in chemistry.
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Affiliation(s)
- Stefan Immel
- Clemens-Schöpf-Institut für Organische Chemie und Biochemie, Technische Universität Darmstadt, Alarich-Weiss-Straße 4, 64287 Darmstadt, Germany
| | - Matthias Köck
- Alfred-Wegener-Institut für Polar- und Meeresforschung in der Helmholtz-Gemeinschaft, Am Handelshafen 12, 27570 Bremerhaven, Germany
| | - Michael Reggelin
- Clemens-Schöpf-Institut für Organische Chemie und Biochemie, Technische Universität Darmstadt, Alarich-Weiss-Straße 4, 64287 Darmstadt, Germany
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10
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Lin Y, Li J, Qin SY, Sun H, Yang YL, Navarro-Vázquez A, Lei X. Programmable alignment media from self-assembled oligopeptide amphiphiles for the measurement of independent sets of residual dipolar couplings in organic solvents. Chem Sci 2022; 13:5838-5845. [PMID: 35685790 PMCID: PMC9131869 DOI: 10.1039/d2sc01057g] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Accepted: 04/14/2022] [Indexed: 11/27/2022] Open
Abstract
NMR spectroscopy in anisotropic media has emerged as a powerful technique for the structural elucidation of organic molecules. Its application requires weak alignment of analytes by means of suitable alignment media. Although a number of alignment media, that are compatible with organic solvents, have been introduced in the last 20 years, acquiring a number of independent, non-linearly related sets of anisotropic NMR data from the same organic solvent system remains a formidable challenge, which is however crucial for the alignment simulations and deriving dynamic and structural information of organic molecules unambiguously. Herein, we introduce a programmable strategy to construct several distinct peptide-based alignment media by adjusting the amino acid sequence, which allows us to measure independent sets of residual dipolar couplings (RDCs) in a highly efficient and accurate manner. This study opens a new avenue for de novo structure determination of organic compounds without requiring prior structural information. We report a programmable strategy to construct multi-alignment media via peptide self-assembly for the measurement of independent sets of residual dipolar couplings (RDCs).![]()
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Affiliation(s)
- Yuexiao Lin
- School of Pharmaceutical Sciences, South-Central University for Nationalities Wuhan 430074 China
| | - Jiaqian Li
- School of Pharmaceutical Sciences, South-Central University for Nationalities Wuhan 430074 China
| | - Si-Yong Qin
- Key Laboratory of Analytical Chemistry of the State Ethnic Affairs Commission, South-Central University for Nationalities Wuhan 430074 China
| | - Han Sun
- Group of Structural Chemistry and Computational Biology, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) 13125 Berlin Germany
| | - Yan-Ling Yang
- School of Pharmaceutical Sciences, South-Central University for Nationalities Wuhan 430074 China
| | - Armando Navarro-Vázquez
- Departamento de Química Fundamental, Universidade Federal de Pernambuco Cidade Universitária CEP 50740-540 Recife PE Brazil
| | - Xinxiang Lei
- School of Pharmaceutical Sciences, South-Central University for Nationalities Wuhan 430074 China .,Key Laboratory of Analytical Chemistry of the State Ethnic Affairs Commission, South-Central University for Nationalities Wuhan 430074 China
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11
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Jin Y, Wang M, Yan YF, Zhang XX, Li XZ, Gao HY. Bridged cassane derivatives from the seeds of Caesalpinia sappan L. and their cytotoxic activities. PHYTOCHEMISTRY 2022; 197:113111. [PMID: 35124529 DOI: 10.1016/j.phytochem.2022.113111] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 01/19/2022] [Accepted: 01/20/2022] [Indexed: 06/14/2023]
Abstract
Two undescribed nitrogen bridged cassane alkaloids (caesanamides A-B) and five undescribed oxygen bridged cassane diterpenoids (caesalpinins JA-JE), together with six known analogs, were isolated and identified from the seeds of Caesalpinia sappan. Their structures, including the absolute configurations, were unequivocally elucidated by the analysis of comprehensive spectroscopic data, ECD calculations, single-crystal X-ray diffraction and the CASE algorithm. Among them, caesanamides A and B represent the first examples of cassane alkaloids bearing unique ring systems of an amide bridge between C-19/C-20 incorporating a 1,3-oxazolidine (6/6/6/5/6/5) or a 7-one-1,3-oxazepine (6/6/6/5/6/7). Caesalpinin JA is an A/B cis-20-norcassane diterpenoid with a rare five-membered oxygen bridge between C-10/C-18. Biological evaluation showed that cassane alkaloids exhibited significant cytotoxicity against HepG2 cells with IC50 values of 13.48 ± 1.07 μM (caesanamide A), 18.91 ± 0.98 μM (caesanamide B), and 7.82 ± 0.65 μM (caesanine B). Further flow cytometry analysis revealed that caesanine B could cause G0G1 cell cycle arrest and promote apoptosis in a dose- and time-dependent manner in HepG2 cells.
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Affiliation(s)
- Yue Jin
- School of Traditional Chinese Materia Medica, Shenyang Pharmaceutical University, Shenyang, 110016, People's Republic of China; Key Laboratory of Structure-Based Drug Design & Discovery of Ministry of Education, Shenyang Pharmaceutical University, Shenyang, 110016, People's Republic of China
| | - Miao Wang
- School of Traditional Chinese Materia Medica, Shenyang Pharmaceutical University, Shenyang, 110016, People's Republic of China; Key Laboratory of Structure-Based Drug Design & Discovery of Ministry of Education, Shenyang Pharmaceutical University, Shenyang, 110016, People's Republic of China
| | - Yan-Fang Yan
- School of Traditional Chinese Materia Medica, Shenyang Pharmaceutical University, Shenyang, 110016, People's Republic of China; Key Laboratory of Structure-Based Drug Design & Discovery of Ministry of Education, Shenyang Pharmaceutical University, Shenyang, 110016, People's Republic of China
| | - Xin-Xin Zhang
- School of Traditional Chinese Materia Medica, Shenyang Pharmaceutical University, Shenyang, 110016, People's Republic of China; Key Laboratory of Structure-Based Drug Design & Discovery of Ministry of Education, Shenyang Pharmaceutical University, Shenyang, 110016, People's Republic of China
| | - Xian-Zhe Li
- School of Traditional Chinese Materia Medica, Shenyang Pharmaceutical University, Shenyang, 110016, People's Republic of China
| | - Hui-Yuan Gao
- School of Traditional Chinese Materia Medica, Shenyang Pharmaceutical University, Shenyang, 110016, People's Republic of China; Key Laboratory of Structure-Based Drug Design & Discovery of Ministry of Education, Shenyang Pharmaceutical University, Shenyang, 110016, People's Republic of China.
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12
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Crouch RC, Raab JG, Pelmuş M, Tischenko E, Frey M, Buevich AV, Reibarkh M, Williamson RT, Martin GE. 19 F-detected dual-optimized inverted 1 J CC 1,n-ADEQUATE. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2022; 60:210-220. [PMID: 34469610 DOI: 10.1002/mrc.5215] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 08/27/2021] [Accepted: 08/30/2021] [Indexed: 06/13/2023]
Abstract
Modification of the recently reported 19 F-detected 1,1-ADEQUATE experiment that incorporates dual-optimization to selectively invert a wide range of 1 JCC correlations in a 1,n-ADEQUATE experiment is reported. Parameters for the dual-optimization segment of the pulse sequence were modified to accommodate the increased size of 1 JCC homonuclear coupling constants of poly- and perfluorinated molecules relative to protonated molecules to allow broadband inversion of the 1 JCC correlations. The observation and utility of isotope shifts are reported for the first time for 1,1- and 1,n-ADEQUATE correlations.
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Affiliation(s)
| | - Jeffrey G Raab
- Department of Chemistry and Biochemistry, University of North Carolina Wilmington, Wilmington, NC, USA
| | - Marius Pelmuş
- Department of Chemistry, Seton Hall University, South Orange, NJ, USA
- Merck and Co., Inc., Kenilworth, NJ, USA
| | | | - Michael Frey
- Analytical Instruments, JEOL USA Inc., Peabody, MA, USA
| | - Alexei V Buevich
- Analytical Research and Development, Merck and Co., Inc., Rahway, NJ, USA
| | - Mikhail Reibarkh
- Analytical Research and Development, Merck and Co., Inc., Rahway, NJ, USA
| | - R Thomas Williamson
- Department of Chemistry and Biochemistry, University of North Carolina Wilmington, Wilmington, NC, USA
| | - Gary E Martin
- Department of Chemistry, Seton Hall University, South Orange, NJ, USA
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13
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Hai Y, Cai ZM, Li PJ, Wei MY, Wang CY, Gu YC, Shao CL. Trends of antimalarial marine natural products: progresses, challenges and opportunities. Nat Prod Rep 2022; 39:969-990. [DOI: 10.1039/d1np00075f] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
This review provides an overview of the antimalarial marine natural products, focusing on their chemistry, malaria-related targets and mechanisms, and highlighting their potential for drug development.
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Affiliation(s)
- Yang Hai
- Key Laboratory of Marine Drugs, The Ministry of Education of China, School of Medicine and Pharmacy, Ocean University of China, Qingdao, 266003, China
| | - Zi-Mu Cai
- Key Laboratory of Marine Drugs, The Ministry of Education of China, School of Medicine and Pharmacy, Ocean University of China, Qingdao, 266003, China
| | - Peng-Jie Li
- Key Laboratory of Marine Drugs, The Ministry of Education of China, School of Medicine and Pharmacy, Ocean University of China, Qingdao, 266003, China
| | - Mei-Yan Wei
- Key Laboratory of Marine Drugs, The Ministry of Education of China, School of Medicine and Pharmacy, Ocean University of China, Qingdao, 266003, China
- College of Food Science and Engineering, Ocean University of China, Qingdao, 266003, China
| | - Chang-Yun Wang
- Key Laboratory of Marine Drugs, The Ministry of Education of China, School of Medicine and Pharmacy, Ocean University of China, Qingdao, 266003, China
- Laboratory for Marine Drugs and Bioproducts, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, 266237, China
| | - Yu-Cheng Gu
- Syngenta Jealott's Hill International Research Centre, Bracknell, Berkshire, RG42 6EY, UK
| | - Chang-Lun Shao
- Key Laboratory of Marine Drugs, The Ministry of Education of China, School of Medicine and Pharmacy, Ocean University of China, Qingdao, 266003, China
- Laboratory for Marine Drugs and Bioproducts, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, 266237, China
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14
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Hwang TL, Yang N, Cheng G, Chen Y, Cui S. Application of 1D 15 N and band-selective 2D 1 H- 15 N CLIP-HSQMBC to detect 35/37 Cl isotope effect on nitrogen for unequivocal structure elucidation of the N-Cl moiety in molecules. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2022; 60:157-164. [PMID: 34376016 DOI: 10.1002/mrc.5204] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 08/04/2021] [Accepted: 08/08/2021] [Indexed: 06/13/2023]
Abstract
An impurity, designated MS204, was isolated from a scale-up production of an intermediate toward the synthesis of an active pharmaceutical ingredient. Structural elucidation of this chloro-containing impurity was performed based on the analysis of the MS and NMR data. Band-selective 2D 1 H-15 N CLIP-HSQMBC experiment was developed to unequivocally identify the ionic N-Cl moiety in the molecule by discovering the two isotope-shifted nitrogen peaks as 3 to 1 ratio separated by about 1 Δ15 N(37/35 Cl) = 19.6 ppb (1.19 Hz) due to the Cl isotope effect. 1D 15 N and 2D 1 H-15 N CLIP-HSQMBC experiments were applied to commercially available compounds to further confirm the techniques by detecting the isotope shift of nitrogen peaks for the N-Cl moiety in molecules.
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Affiliation(s)
| | - Ning Yang
- Attribute Sciences, Amgen Inc., Thousand Oaks, CA, USA
| | - Guilong Cheng
- Attribute Sciences, Amgen Inc., Thousand Oaks, CA, USA
- Department of Analytical Development and QC, Foghorn Therapeutics, Cambridge, MA, USA
| | - Ying Chen
- Drug Substance Technologies, Amgen Inc., Thousand Oaks, CA, USA
- Chemical Development, CMC, Neurocrine Biosciences, San Diego, CA, USA
| | - Sheng Cui
- Drug Substance Technologies, Amgen Inc., Thousand Oaks, CA, USA
- CMC, New Amsterdam Pharma, Miami, FL, USA
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15
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Immel S, Köck M, Reggelin M. NMR-Based Configurational Assignments of Natural Products: Gibbs Sampling and Bayesian Inference Using Floating Chirality Distance Geometry Calculations. Mar Drugs 2021; 20:14. [PMID: 35049868 PMCID: PMC8781118 DOI: 10.3390/md20010014] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 12/12/2021] [Accepted: 12/20/2021] [Indexed: 02/07/2023] Open
Abstract
Floating chirality restrained distance geometry (fc-rDG) calculations are used to directly evolve structures from NMR data such as NOE-derived intramolecular distances or anisotropic residual dipolar couplings (RDCs). In contrast to evaluating pre-calculated structures against NMR restraints, multiple configurations (diastereomers) and conformations are generated automatically within the experimental limits. In this report, we show that the "unphysical" rDG pseudo energies defined from NMR violations bear statistical significance, which allows assigning probabilities to configurational assignments made that are fully compatible with the method of Bayesian inference. These "diastereomeric differentiabilities" then even become almost independent of the actual values of the force constants used to model the restraints originating from NOE or RDC data.
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Affiliation(s)
- Stefan Immel
- Clemens-Schöpf-Institut für Organische Chemie und Biochemie, Technische Universität Darmstadt, Alarich-Weiss-Straße 4, 64287 Darmstadt, Germany
| | - Matthias Köck
- Alfred-Wegener-Institut für Polar-und Meeresforschung in der Helmholtz-Gemeinschaft, Am Handelshafen 12, 27570 Bremerhaven, Germany;
| | - Michael Reggelin
- Clemens-Schöpf-Institut für Organische Chemie und Biochemie, Technische Universität Darmstadt, Alarich-Weiss-Straße 4, 64287 Darmstadt, Germany
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16
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Tempone AG, Pieper P, Borborema SET, Thevenard F, Lago JHG, Croft SL, Anderson EA. Marine alkaloids as bioactive agents against protozoal neglected tropical diseases and malaria. Nat Prod Rep 2021; 38:2214-2235. [PMID: 34913053 PMCID: PMC8672869 DOI: 10.1039/d0np00078g] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Indexed: 01/09/2023]
Abstract
Covering: 2000 up to 2021Natural products are an important resource in drug discovery, directly or indirectly delivering numerous small molecules for potential development as human medicines. Among the many classes of natural products, alkaloids have a rich history of therapeutic applications. The extensive chemodiversity of alkaloids found in the marine environment has attracted considerable attention for such uses, while the scarcity of these natural materials has stimulated efforts towards their total synthesis. This review focuses on the biological activity of marine alkaloids (covering 2000 to up to 2021) towards Neglected Tropical Diseases (NTDs) caused by protozoan parasites, and malaria. Chemotherapy represents the only form of treatment for Chagas disease, human African trypanosomiasis, leishmaniasis and malaria, but there is currently a restricted arsenal of drugs, which often elicit severe adverse effects, show variable efficacy or resistance, or are costly. Natural product scaffolds have re-emerged as a focus of academic drug discovery programmes, offering a different resource to discover new chemical entities with new modes of action. In this review, the potential of a range of marine alkaloids is analyzed, accompanied by coverage of synthetic efforts that enable further studies of key antiprotozoal natural product scaffolds.
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Affiliation(s)
- Andre G Tempone
- Centre for Parasitology and Mycology, Instituto Adolfo Lutz, São Paulo, 01246-000, Brazil.
| | - Pauline Pieper
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, UK.
| | - Samanta E T Borborema
- Centre for Parasitology and Mycology, Instituto Adolfo Lutz, São Paulo, 01246-000, Brazil.
| | - Fernanda Thevenard
- Centre of Natural Sciences and Humanities, Federal University of ABC, Sao Paulo, 09210-580, Brazil
| | - Joao Henrique G Lago
- Centre of Natural Sciences and Humanities, Federal University of ABC, Sao Paulo, 09210-580, Brazil
| | - Simon L Croft
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK.
| | - Edward A Anderson
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, UK.
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17
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Elyashberg M, Argyropoulos D. Computer Assisted Structure Elucidation (CASE): Current and future perspectives. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2021; 59:669-690. [PMID: 33197069 DOI: 10.1002/mrc.5115] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 10/31/2020] [Accepted: 11/08/2020] [Indexed: 06/11/2023]
Abstract
The first efforts for the development of methods for Computer-Assisted Structure Elucidation (CASE) were published more than 50 years ago. CASE expert systems based on one-dimensional (1D) and two-dimensional (2D) Nuclear Magnetic Resonance (NMR) data have matured considerably by now. The structures of a great number of complex natural products have been elucidated and/or revised using such programs. In this article, we discuss the most likely directions in which CASE will evolve. We act on the premise that a synergistic interaction exists between CASE, new NMR experiments, and methods of computational chemistry, which are continuously being improved. The new developments in NMR experiments (long-range correlation experiments, pure-shift methods, coupling constants measurement and prediction, residual dipolar couplings [RDCs]), and residual chemical shift anisotropies [RCSAs], evolution of density functional theory (DFT), and machine learning algorithms will have an influence on CASE systems and vice versa. This is true also for new techniques for chemical analysis (Atomic Force Microscopy [AFM], "crystalline sponge" X-ray analysis, and micro-Electron Diffraction [micro-ED]), which will be used in combination with expert systems. We foresee that CASE will be utilized widely and become a routine tool for NMR spectroscopists and analysts in academic and industrial laboratories. We believe that the "golden age" of CASE is still in the future.
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18
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Köck M, Reggelin M, Immel S. Model-Free Approach for the Configurational Analysis of Marine Natural Products. Mar Drugs 2021; 19:md19060283. [PMID: 34063741 PMCID: PMC8223791 DOI: 10.3390/md19060283] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 05/09/2021] [Accepted: 05/11/2021] [Indexed: 12/17/2022] Open
Abstract
The NMR-based configurational analysis of complex marine natural products is still not a routine task. Different NMR parameters are used for the assignment of the relative configuration: NOE/ROE, homo- and heteronuclear J couplings as well as anisotropic parameters. The combined distance geometry (DG) and distance bounds driven dynamics (DDD) method allows a model-free approach for the determination of the relative configuration that is invariant to the choice of an initial starting structure and does not rely on comparisons with (DFT) calculated structures. Here, we will discuss the configurational analysis of five complex marine natural products or synthetic derivatives thereof: the cis-palau’amine derivatives 1a and 1b, tetrabromostyloguanidine (1c), plakilactone H (2), and manzamine A (3). The certainty of configurational assignments is evaluated in view of the accuracy of the NOE/ROE data available. These case studies will show the prospective breadth of application of the DG/DDD method.
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Affiliation(s)
- Matthias Köck
- Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany
- Correspondence: (M.K.); (S.I.)
| | - Michael Reggelin
- Clemens-Schöpf-Institute for Organic Chemistry and Biochemistry, Technical University of Darmstadt, Alarich-Weiss-Straße 4, 64287 Darmstadt, Germany;
| | - Stefan Immel
- Clemens-Schöpf-Institute for Organic Chemistry and Biochemistry, Technical University of Darmstadt, Alarich-Weiss-Straße 4, 64287 Darmstadt, Germany;
- Correspondence: (M.K.); (S.I.)
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19
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Tran TD, Cartner LK, Bokesch HR, Henrich CJ, Wang XW, Mahidol C, Ruchirawat S, Kittakoop P, O'Keefe BR, Gustafson KR. NMR characterization of rearranged staurosporine aglycone analogues from the marine sponge Damiria sp. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2021; 59:534-539. [PMID: 31379005 PMCID: PMC7428849 DOI: 10.1002/mrc.4932] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 07/22/2019] [Accepted: 07/26/2019] [Indexed: 06/10/2023]
Abstract
The indolocarbazole family of bisindole alkaloids is best known for the natural product staurosporine, a protein kinase C inhibitor that belongs to the indolo[2,3-a]carbazole structural class. A large number of other indolo[2,3-a]carbazoles have subsequently been isolated and identified, but other isomeric forms of indolocarbazole natural products have rarely been reported. An extract of the marine sponge Damiria sp., which represents an understudied genus, provided two novel alkaloids named damirines A (1) and B (2). Their structures were assigned by comprehensive NMR spectroscopic analyses, and for compound 2, this included application of the LR-HSQMBC pulse sequence, a long-range heteronuclear correlation experiment that has particular utility for defining proton-deficient scaffolds. The damirines represent a new hexacyclic carbon-nitrogen framework comprised of an indolo[3,2-a]carbazole fused with either an aminoimidazole or a imidazolone ring. Compound 1 showed selective cytotoxic properties toward six different cell lines in the NCI-60 cancer screen.
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Affiliation(s)
- Trong D Tran
- Molecular Targets Program, Center for Cancer Research, National Cancer Institute, Frederick, MD
| | - Laura K Cartner
- Molecular Targets Program, Center for Cancer Research, National Cancer Institute, Frederick, MD
- Basic Science Program, Leidos Biomedical Research, Inc., National Cancer Institute-Frederick National Laboratory for Cancer Research, Frederick, MD
| | - Heidi R Bokesch
- Molecular Targets Program, Center for Cancer Research, National Cancer Institute, Frederick, MD
- Basic Science Program, Leidos Biomedical Research, Inc., National Cancer Institute-Frederick National Laboratory for Cancer Research, Frederick, MD
| | - Curtis J Henrich
- Molecular Targets Program, Center for Cancer Research, National Cancer Institute, Frederick, MD
- Basic Science Program, Leidos Biomedical Research, Inc., National Cancer Institute-Frederick National Laboratory for Cancer Research, Frederick, MD
| | - Xin W Wang
- Laboratory of Human Carcinogenesis, Center for Cancer Research, National Cancer Institute, Bethesda, MD
| | - Chulabhorn Mahidol
- Chulabhorn Research Institute, Office of Research, Laboratory of Natural Products, Bangkok, Thailand
- Chulabhorn Graduate Institute, Chemical Biology Program, Chulabhorn Royal Academy, Bangkok, Thailand
| | - Somsak Ruchirawat
- Chulabhorn Research Institute, Office of Research, Laboratory of Natural Products, Bangkok, Thailand
- Chulabhorn Graduate Institute, Chemical Biology Program, Chulabhorn Royal Academy, Bangkok, Thailand
- Center of Excellence on Environmental Health and Toxicology (EHT), CHE, Ministry of Education, Bangkok, Thailand
| | - Prasat Kittakoop
- Chulabhorn Research Institute, Office of Research, Laboratory of Natural Products, Bangkok, Thailand
- Chulabhorn Graduate Institute, Chemical Biology Program, Chulabhorn Royal Academy, Bangkok, Thailand
- Center of Excellence on Environmental Health and Toxicology (EHT), CHE, Ministry of Education, Bangkok, Thailand
| | - Barry R O'Keefe
- Molecular Targets Program, Center for Cancer Research, National Cancer Institute, Frederick, MD
| | - Kirk R Gustafson
- Molecular Targets Program, Center for Cancer Research, National Cancer Institute, Frederick, MD
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20
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Abstract
This review covers the literature published between January and December in 2018 for marine natural products (MNPs), with 717 citations (706 for the period January to December 2018) referring to compounds isolated from marine microorganisms and phytoplankton, green, brown and red algae, sponges, cnidarians, bryozoans, molluscs, tunicates, echinoderms, mangroves and other intertidal plants and microorganisms. The emphasis is on new compounds (1554 in 469 papers for 2018), together with the relevant biological activities, source organisms and country of origin. Reviews, biosynthetic studies, first syntheses, and syntheses that led to the revision of structures or stereochemistries, have been included. The proportion of MNPs assigned absolute configuration over the last decade is also surveyed.
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Affiliation(s)
- Anthony R Carroll
- School of Environment and Science, Griffith University, Gold Coast, Australia. and Griffith Institute for Drug Discovery, Griffith University, Brisbane, Australia
| | - Brent R Copp
- School of Chemical Sciences, University of Auckland, Auckland, New Zealand
| | - Rohan A Davis
- Griffith Institute for Drug Discovery, Griffith University, Brisbane, Australia and School of Environment and Science, Griffith University, Brisbane, Australia
| | - Robert A Keyzers
- Centre for Biodiscovery, School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington, New Zealand
| | - Michèle R Prinsep
- Chemistry, School of Science, University of Waikato, Hamilton, New Zealand
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21
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Abstract
Halogens cause pronounced and systematic effects on the 13C NMR chemical shift (δ13C) of an adjacent carbon nucleus, usually leading to a decrease in the values across the halogen series. Although this normal halogen dependence (NHD) is known in organic and inorganic compounds containing the carbon atom in its neutral and cationic forms, information about carbanions is scarce. To understand how δ13C changes in molecules with different charges, the shielding mechanisms of CHX3, CX3+, and CX3- (X = Cl, Br, or I) systems are investigated via density functional theory calculations and further analyzed by decomposition into contributions of natural localized molecular orbitals. An inverse halogen dependence (IHD) is determined for the anion series as a result of the negative spin-orbit contribution instead of scalar paramagnetic effects. The presence of a carbon nonbonding orbital in anions allows magnetic couplings that generate a deshielding effect on the nucleus and contradicts the classical association between δ13C and atomic charge.
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Affiliation(s)
- Renan V Viesser
- Institute of Chemistry, University of Campinas - UNICAMP, P.O. Box 6154, 13083-970, Campinas, São Paulo, Brazil.
| | - Cláudio F Tormena
- Institute of Chemistry, University of Campinas - UNICAMP, P.O. Box 6154, 13083-970, Campinas, São Paulo, Brazil.
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22
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Bennett R, Pirrone GF, Nowak T, Mukherjee D, Shchurik V, Mapelli C, Hickey JL, Regalado EL, Mangion I, Makarov AA. Ultra-high-throughput SPE-MALDI workflow: Blueprint for efficient purification and screening of peptide libraries. Anal Chim Acta 2021; 1142:10-18. [PMID: 33280687 DOI: 10.1016/j.aca.2020.10.045] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Revised: 10/19/2020] [Accepted: 10/21/2020] [Indexed: 12/30/2022]
Abstract
At the forefront of synthetic endeavors in the pharmaceutical industry, including drug discovery and high-throughput screening, timelines are tight and large quantities of pure chemical targets are rarely available. In this regard, the development of novel and increasingly challenging chemistries requires a commensurate level of innovation to develop reliable analytical assays and purification workflows with rapid turnaround that enables accelerated pharmacological evaluation. A small-scale automation platform enabling high-throughput analysis and purification to streamline the selection of candidate leads would be a transformative advance. Herein, we introduce an automation-friendly solid-phase extraction-matrix-assisted laser desorption/ionization (SPE-MALDI) platform applied to the high-throughput purification and analysis of peptide libraries. This advance enabled us to purify peptides from microgram levels in less than a day with results comparable to traditional high-performance liquid chromatography-diode array detection-mass spectrometry (HPLC-DAD-MS).
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Affiliation(s)
- Raffeal Bennett
- Merck & Co., Inc., MRL, Analytical Research & Development, Rahway, NJ, 07065, USA.
| | - Gregory F Pirrone
- Merck & Co., Inc., MRL, Analytical Research & Development, Rahway, NJ, 07065, USA.
| | - Timothy Nowak
- Merck & Co., Inc., MRL, Analytical Research & Development, Rahway, NJ, 07065, USA
| | - Debopreeti Mukherjee
- Merck & Co., Inc., MRL, Analytical Research & Development, Rahway, NJ, 07065, USA
| | - Vladimir Shchurik
- Merck & Co., Inc., MRL, Analytical Research & Development, Rahway, NJ, 07065, USA
| | - Claudio Mapelli
- Merck & Co., Inc., MRL, Chemistry Capabilities for Accelerating Therapeutics, Discovery Chemistry, Kenilworth, NJ, 07033, USA
| | - Jennifer L Hickey
- Merck & Co., Inc., MRL, Chemistry Capabilities for Accelerating Therapeutics, Discovery Chemistry, Kenilworth, NJ, 07033, USA
| | - Erik L Regalado
- Merck & Co., Inc., MRL, Analytical Research & Development, Rahway, NJ, 07065, USA.
| | - Ian Mangion
- Merck & Co., Inc., MRL, Analytical Research & Development, Rahway, NJ, 07065, USA
| | - Alexey A Makarov
- Merck & Co., Inc., MRL, Analytical Research & Development, Rahway, NJ, 07065, USA
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23
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Daranas AH, Sarotti AM. Are Computational Methods Useful for Structure Elucidation of Large and Flexible Molecules? Belizentrin as a Case Study. Org Lett 2020; 23:503-507. [PMID: 33382270 DOI: 10.1021/acs.orglett.0c04016] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Quantum mechanical NMR methods are progressively becoming decisive in structure elucidation. However, problems arise using low-level calculations for complex molecules, whereas methods using higher levels of theory are not practical for large molecules. This report outlines a synergistic effort employing computationally inexpensive quantum mechanical NMR calculations with conformer selection incorporating 3JHH values as a way to solve the structure of large, complex, and highly flexible molecules using readily available computational resources with belizentrin as a case study.
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Affiliation(s)
- Antonio Hernández Daranas
- Instituto de Productos Naturales y Agrobiología, Consejo Superior de Investigaciones Científicas (IPNA-CSIC), La Laguna 38206, Tenerife, Spain
| | - Ariel M Sarotti
- Instituto de Química Rosario (CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, Rosario 2000, Argentina
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24
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van der Westhuyzen AE, Ingels A, Rosière R, Amighi K, Oberer L, Gustafson KR, Wang D, Evidente A, Maddau L, Masi M, de Villiers A, Green IR, Berger W, Kornienko A, Mathieu V, van Otterlo WAL. Deciphering the chemical instability of sphaeropsidin A under physiological conditions - degradation studies and structural elucidation of the major metabolite. Org Biomol Chem 2020; 18:8147-8160. [PMID: 33016969 PMCID: PMC7881364 DOI: 10.1039/d0ob01586e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The fungal metabolite sphaeropsidin A (SphA) has been recognised for its promising cytotoxicity, particularly towards apoptosis- and multidrug-resistant cancers. Owing to its intriguing activity, the development of SphA as a potential anticancer agent has been pursued. However, this endeavour is compromised since SphA exhibits poor physicochemical stability under physiological conditions. Herein, SphA's instability in biological media was explored utilizing LC-MS. Notably, the degradation tendency was found to be markedly enhanced in the presence of amino acids in the cell medium utilized. Furthermore, the study investigated the presence of degradation adducts, including the identification, isolation and structural elucidation of a major degradation metabolite, (4R)-4,4',4'-trimethyl-3'-oxo-4-vinyl-4',5',6',7'-tetrahydro-3'H-spiro[cyclohexane-1,1'-isobenzofuran]-2-ene-2-carboxylic acid. Considering the reduced cytotoxic potency of aged SphA solutions, as well as that of the isolated degradation metabolite, the reported antiproliferative activity has been attributed primarily to the parent compound (SphA) and not its degradation species. The fact that SphA continues to exhibit remarkable bioactivity, despite being susceptible to degradation, motivates future research efforts to address the challenges associated with this instability impediment.
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Affiliation(s)
- Alet E van der Westhuyzen
- Department of Chemistry and Polymer Science, University of Stellenbosch, Matieland, 7600, Stellenbosch, Western Cape, South Africa.
| | - Aude Ingels
- Department of Pharmacotherapy and Pharmaceutics, Université libre de Bruxelles (ULB), Boulevard du Triomphe, Accès 2, 1050 Ixelles, Belgium. and ULB Cancer Research Center, Université libre de Bruxelles (ULB), 1050 Bruxelles, Belgium
| | - Rémi Rosière
- Department of Pharmacotherapy and Pharmaceutics, Université libre de Bruxelles (ULB), Boulevard du Triomphe, Accès 2, 1050 Ixelles, Belgium.
| | - Karim Amighi
- Department of Pharmacotherapy and Pharmaceutics, Université libre de Bruxelles (ULB), Boulevard du Triomphe, Accès 2, 1050 Ixelles, Belgium.
| | - Lukas Oberer
- Novartis Institutes for BioMedical Research, Global Discovery Chemistry, Basel, Switzerland
| | - Kirk R Gustafson
- Molecular Targets Program, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702-1201, USA
| | - Dongdong Wang
- Molecular Targets Program, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702-1201, USA
| | - Antonio Evidente
- Department of Chemical Sciences, University of Naples Federico II, Complesso Universitario Monte S. Angelo, Via Cintia 4, 80126 Naples, Italy
| | - Lucia Maddau
- Department of Agriculture, Section of Plant Pathology and Entomology, University of Sassari, Viale Italia 39, 07100, Sassari, Italy
| | - Marco Masi
- Department of Chemical Sciences, University of Naples Federico II, Complesso Universitario Monte S. Angelo, Via Cintia 4, 80126 Naples, Italy
| | - André de Villiers
- Department of Chemistry and Polymer Science, University of Stellenbosch, Matieland, 7600, Stellenbosch, Western Cape, South Africa.
| | - Ivan R Green
- Department of Chemistry and Polymer Science, University of Stellenbosch, Matieland, 7600, Stellenbosch, Western Cape, South Africa.
| | - Walter Berger
- Department of Medicine I, Institute of Cancer Research and Comprehensive Cancer Center, Medical University of Vienna, Vienna, Austria
| | - Alexander Kornienko
- Department of Chemistry and Biochemistry, Texas State University, San Marcos, Texas 78666, USA
| | - Veronique Mathieu
- Department of Pharmacotherapy and Pharmaceutics, Université libre de Bruxelles (ULB), Boulevard du Triomphe, Accès 2, 1050 Ixelles, Belgium. and ULB Cancer Research Center, Université libre de Bruxelles (ULB), 1050 Bruxelles, Belgium
| | - Willem A L van Otterlo
- Department of Chemistry and Polymer Science, University of Stellenbosch, Matieland, 7600, Stellenbosch, Western Cape, South Africa.
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25
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Ndukwe IE, Lam YH, Pandey SK, Haug BE, Bayer A, Sherer EC, Blinov KA, Williamson RT, Isaksson J, Reibarkh M, Liu Y, Martin GE. Unequivocal structure confirmation of a breitfussin analog by anisotropic NMR measurements. Chem Sci 2020; 11:12081-12088. [PMID: 34094423 PMCID: PMC8162999 DOI: 10.1039/d0sc03664a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Structural features of proton-deficient heteroaromatic natural products, such as the breitfussins, can severely complicate their characterization by NMR spectroscopy. For the breitfussins in particular, the constitution of the five-membered oxazole central ring cannot be unequivocally established via conventional NMR methods when the 4′-position is halogenated. The level of difficulty is exacerbated by 4′-iodination, as the accuracy with which theoretical NMR parameters are determined relies extensively on computational treatment of the relativistic effects of the iodine atom. It is demonstrated in the present study, that the structure of a 4′-iodo breitfussin analog can be unequivocally established by anisotropic NMR methods, by adopting a reduced singular value decomposition (SVD) protocol that leverages the planar structures exhibited by its conformers. Structural features of proton-deficient heteroaromatic natural products, such as the breitfussins, can severely complicate their characterization by NMR spectroscopy.![]()
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Affiliation(s)
- Ikenna E Ndukwe
- Analytical Research & Development, (Rahway), Merck & Co. Inc. Kenilworth NJ USA
| | - Yu-Hong Lam
- Computational and Structural Chemistry, Merck & Co., Inc. Rahway NJ 07065 USA
| | - Sunil K Pandey
- Department of Chemistry and Centre for Pharmacy, University of Bergen Allégaten 41 NO-5020 Bergen Norway
| | - Bengt E Haug
- Department of Chemistry and Centre for Pharmacy, University of Bergen Allégaten 41 NO-5020 Bergen Norway
| | - Annette Bayer
- Department of Chemistry, UiT the Arctic University of Tromsø NO-9037 Tromsø Norway
| | - Edward C Sherer
- Analytical Research & Development, (Rahway), Merck & Co. Inc. Kenilworth NJ USA
| | - Kirill A Blinov
- MestReLab Research S. L. Santiago de Compostela A Coruna 15706 Spain
| | - R Thomas Williamson
- Analytical Research & Development, (Rahway), Merck & Co. Inc. Kenilworth NJ USA
| | - Johan Isaksson
- Department of Chemistry, UiT the Arctic University of Tromsø NO-9037 Tromsø Norway
| | - Mikhail Reibarkh
- Analytical Research & Development, (Rahway), Merck & Co. Inc. Kenilworth NJ USA
| | - Yizhou Liu
- Analytical Research & Development, (Rahway), Merck & Co. Inc. Kenilworth NJ USA
| | - Gary E Martin
- Analytical Research & Development, (Rahway), Merck & Co. Inc. Kenilworth NJ USA
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26
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Qin S, Jiang Y, Sun H, Liu H, Zhang A, Lei X. Measurement of Residual Dipolar Couplings of Organic Molecules in Multiple Solvent Systems Using a Liquid‐Crystalline‐Based Medium. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202007243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Si‐Yong Qin
- Key Laboratory of Catalysis and Energy Materials Chemistry of Ministry of Education & Hubei Key Laboratory of Catalysis and Materials Science South-Central University for Nationalities Wuhan 430074 China
| | - Yan Jiang
- Key Laboratory of Catalysis and Energy Materials Chemistry of Ministry of Education & Hubei Key Laboratory of Catalysis and Materials Science South-Central University for Nationalities Wuhan 430074 China
| | - Han Sun
- Section of Structural Biology Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) 13125 Berlin Germany
| | - Han Liu
- School of Pharmaceutical Sciences South-Central University for Nationalities Wuhan 430074 China
| | - Ai‐Qing Zhang
- Key Laboratory of Catalysis and Energy Materials Chemistry of Ministry of Education & Hubei Key Laboratory of Catalysis and Materials Science South-Central University for Nationalities Wuhan 430074 China
| | - Xinxiang Lei
- Key Laboratory of Catalysis and Energy Materials Chemistry of Ministry of Education & Hubei Key Laboratory of Catalysis and Materials Science South-Central University for Nationalities Wuhan 430074 China
- School of Pharmaceutical Sciences South-Central University for Nationalities Wuhan 430074 China
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27
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Qin S, Jiang Y, Sun H, Liu H, Zhang A, Lei X. Measurement of Residual Dipolar Couplings of Organic Molecules in Multiple Solvent Systems Using a Liquid‐Crystalline‐Based Medium. Angew Chem Int Ed Engl 2020; 59:17097-17103. [DOI: 10.1002/anie.202007243] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Indexed: 01/08/2023]
Affiliation(s)
- Si‐Yong Qin
- Key Laboratory of Catalysis and Energy Materials Chemistry of Ministry of Education & Hubei Key Laboratory of Catalysis and Materials Science South-Central University for Nationalities Wuhan 430074 China
| | - Yan Jiang
- Key Laboratory of Catalysis and Energy Materials Chemistry of Ministry of Education & Hubei Key Laboratory of Catalysis and Materials Science South-Central University for Nationalities Wuhan 430074 China
| | - Han Sun
- Section of Structural Biology Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) 13125 Berlin Germany
| | - Han Liu
- School of Pharmaceutical Sciences South-Central University for Nationalities Wuhan 430074 China
| | - Ai‐Qing Zhang
- Key Laboratory of Catalysis and Energy Materials Chemistry of Ministry of Education & Hubei Key Laboratory of Catalysis and Materials Science South-Central University for Nationalities Wuhan 430074 China
| | - Xinxiang Lei
- Key Laboratory of Catalysis and Energy Materials Chemistry of Ministry of Education & Hubei Key Laboratory of Catalysis and Materials Science South-Central University for Nationalities Wuhan 430074 China
- School of Pharmaceutical Sciences South-Central University for Nationalities Wuhan 430074 China
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28
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Ndukwe IE, Wang X, Lam NYS, Ermanis K, Alexander KL, Bertin MJ, Martin GE, Muir G, Paterson I, Britton R, Goodman JM, Helfrich EJN, Piel J, Gerwick WH, Williamson RT. Synergism of anisotropic and computational NMR methods reveals the likely configuration of phormidolide A. Chem Commun (Camb) 2020; 56:7565-7568. [PMID: 32520016 PMCID: PMC7436192 DOI: 10.1039/d0cc03055d] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Characterization of the complex molecular scaffold of the marine polyketide natural product phormidolide A represents a challenge that has persisted for nearly two decades. In light of discordant results arising from recent synthetic and biosynthetic reports, a rigorous study of the configuration of phormidolide A was necessary. This report outlines a synergistic effort employing computational and anisotropic NMR investigation, that provided orthogonal confirmation of the reassigned side chain, as well as supporting a further correction of the C7 stereocenter.
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Affiliation(s)
- Ikenna E Ndukwe
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, USA
| | - Xiao Wang
- Analytical Research & Development, Merck & Co. Inc, Rahway, NJ, USA
| | - Nelson Y S Lam
- University Chemical Laboratory, Lensfield Road, Cambridge, CB2 1EW, UK
| | - Kristaps Ermanis
- University Chemical Laboratory, Lensfield Road, Cambridge, CB2 1EW, UK
| | - Kelsey L Alexander
- Scripps Institution of Oceanography and Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, CA, USA and Department of Chemistry, University of California, San Diego, CA, USA
| | - Matthew J Bertin
- Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, RI, USA
| | - Gary E Martin
- Department of Chemistry, Seton Hall University, South Orange, NJ, USA
| | - Garrett Muir
- Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia V5A 1S6, Canada
| | - Ian Paterson
- University Chemical Laboratory, Lensfield Road, Cambridge, CB2 1EW, UK
| | - Robert Britton
- Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia V5A 1S6, Canada
| | | | - Eric J N Helfrich
- Institute of Microbiology, Eidgenössische Technische Hochschule (ETH) Zürich, Zurich, Switzerland
| | - Jörn Piel
- Institute of Microbiology, Eidgenössische Technische Hochschule (ETH) Zürich, Zurich, Switzerland
| | - William H Gerwick
- Scripps Institution of Oceanography and Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, CA, USA
| | - R Thomas Williamson
- Department of Chemistry & Biochemistry, University of North Carolina Wilmington, Wilmington, NC, USA.
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29
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Motiram-Corral K, Nolis P, Saurí J, Parella T. LR-HSQMBC versus LR-selHSQMBC: Enhancing the Observation of Tiny Long-Range Heteronuclear NMR Correlations. JOURNAL OF NATURAL PRODUCTS 2020; 83:1275-1282. [PMID: 32155071 DOI: 10.1021/acs.jnatprod.0c00058] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The detection of ultra-long-range (4JCH and higher) heteronuclear connectivities can complement the conventional use of HMBC/HSQMBC data in structure elucidation NMR studies of proton-deficient natural products, where two-bond and three-bond correlations are usually observed. The performance of the selHSQMBC experiment with respect to its broadband HSQMBC counterpart is evaluated. Despite its frequency-selectivity nature, selHSQMBC efficiently prevents any unwanted signal phase and intensity modulations due to passive proton-proton coupling constants typically involved in HSQMBC. As a result, selHSQMBC offers a significant sensitivity enhancement and provides pure in-phase multiplets, improving the detection levels for short- and long-range cross-peaks corresponding to small heteronuclear coupling values. This is particularly relevant for experiments optimized to small nJCH values (2-3 Hz), referred to as LR-selHSQMBC, where key cross-peaks that are not visible in the equivalent broadband LR-HSQMBC spectrum can become observable in optimum conditions.
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Affiliation(s)
- Kumar Motiram-Corral
- Servei de Ressonància Magnètica Nuclear, Universitat Autònoma de Barcelona, E-08193 Bellaterra, Barcelona, Catalonia, Spain
| | - Pau Nolis
- Servei de Ressonància Magnètica Nuclear, Universitat Autònoma de Barcelona, E-08193 Bellaterra, Barcelona, Catalonia, Spain
| | - Josep Saurí
- Structure Elucidation Group, Analytical Research & Development, Merck & Co., Inc., 33 Avenue Louis Pasteur, Boston, Massachusetts 02115, United States
| | - Teodor Parella
- Servei de Ressonància Magnètica Nuclear, Universitat Autònoma de Barcelona, E-08193 Bellaterra, Barcelona, Catalonia, Spain
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30
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Ciavatta ML, Lefranc F, Vieira LM, Kiss R, Carbone M, van Otterlo WAL, Lopanik NB, Waeschenbach A. The Phylum Bryozoa: From Biology to Biomedical Potential. Mar Drugs 2020; 18:E200. [PMID: 32283669 PMCID: PMC7230173 DOI: 10.3390/md18040200] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 03/31/2020] [Accepted: 04/06/2020] [Indexed: 01/06/2023] Open
Abstract
Less than one percent of marine natural products characterized since 1963 have been obtained from the phylum Bryozoa which, therefore, still represents a huge reservoir for the discovery of bioactive metabolites with its ~6000 described species. The current review is designed to highlight how bryozoans use sophisticated chemical defenses against their numerous predators and competitors, and which can be harbored for medicinal uses. This review collates all currently available chemoecological data about bryozoans and lists potential applications/benefits for human health. The core of the current review relates to the potential of bryozoan metabolites in human diseases with particular attention to viral, brain, and parasitic diseases. It additionally weighs the pros and cons of total syntheses of some bryozoan metabolites versus the synthesis of non-natural analogues, and explores the hopes put into the development of biotechnological approaches to provide sustainable amounts of bryozoan metabolites without harming the natural environment.
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Affiliation(s)
- Maria Letizia Ciavatta
- Consiglio Nazionale delle Ricerche (CNR), Istituto di Chimica Biomolecolare (ICB), Via Campi Flegrei 34, 80078 Pozzuoli, Italy; (M.L.C.); (M.C.)
| | - Florence Lefranc
- Service de Neurochirurgie, Hôpital Erasme, Université Libre de Bruxelles (ULB), 1070 Brussels, Belgium
| | - Leandro M. Vieira
- Departamento de Zoologia, Centro de Biociências, Universidade Federal de Pernambuco, Recife, PE 50670-901, Brazil;
| | - Robert Kiss
- Retired – formerly at the Fonds National de la Recherche Scientifique (FRS-FNRS), 1000 Brussels, Belgium;
| | - Marianna Carbone
- Consiglio Nazionale delle Ricerche (CNR), Istituto di Chimica Biomolecolare (ICB), Via Campi Flegrei 34, 80078 Pozzuoli, Italy; (M.L.C.); (M.C.)
| | - Willem A. L. van Otterlo
- Department of Chemistry and Polymer Science, University of Stellenbosch, Private Bag X1, Matieland 7602, South Africa;
| | - Nicole B. Lopanik
- School of Earth and Atmospheric Sciences, School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA;
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31
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Ibáñez de Opakua A, Klama F, Ndukwe IE, Martin GE, Williamson RT, Zweckstetter M. Determination of Complex Small-Molecule Structures Using Molecular Alignment Simulation. Angew Chem Int Ed Engl 2020; 59:6172-6176. [PMID: 31971323 PMCID: PMC7187346 DOI: 10.1002/anie.202000311] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 01/23/2020] [Indexed: 11/12/2022]
Abstract
Correct structural assignment of small molecules and natural products is critical for drug discovery and organic chemistry. Anisotropy-based NMR spectroscopy is a powerful tool for the structural assignment of organic molecules, but it relies on the utilization of a medium that disrupts the isotropic motion of molecules in organic solvents. Here, we establish a quantitative correlation between the atomic structure of the alignment medium, the molecular structure of the small molecule, and molecule-specific anisotropic NMR parameters. The quantitative correlation uses an accurate three-dimensional molecular alignment model that predicts residual dipolar couplings of small molecules aligned by poly(γ-benzyl-l-glutamate). The technique facilitates reliable determination of the correct stereoisomer and enables unequivocal, rapid determination of complex molecular structures from extremely sparse NMR data.
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Affiliation(s)
- Alain Ibáñez de Opakua
- Structural Biology in DementiaGerman Center for Neurodegenerative Diseases (DZNE)Von-Siebold-Strasse 3a37075GöttingenGermany
| | - Frederik Klama
- Department for NMR-based Structural BiologyMax Planck Institute for Biophysical ChemistryAm Fassberg 1137077GöttingenGermany
| | - Ikenna E. Ndukwe
- Analytical Research & Development (Rahway)Merck & Co. Inc.KenilworthNJUSA
- Complex Carbohydrate Research CenterUniversity of GeorgiaAthensGA30602USA
| | - Gary E. Martin
- Analytical Research & Development (Rahway)Merck & Co. Inc.KenilworthNJUSA
- Department of Chemistry and BiochemistrySeton Hall UniversitySouth OrangeNJ07079USA
| | - R. Thomas Williamson
- Analytical Research & Development (Rahway)Merck & Co. Inc.KenilworthNJUSA
- Department of Chemistry & BiochemistryUniversity of North Carolina WilmingtonWilmingtonNC28409USA
| | - Markus Zweckstetter
- Structural Biology in DementiaGerman Center for Neurodegenerative Diseases (DZNE)Von-Siebold-Strasse 3a37075GöttingenGermany
- Department for NMR-based Structural BiologyMax Planck Institute for Biophysical ChemistryAm Fassberg 1137077GöttingenGermany
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32
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Ibáñez de Opakua A, Klama F, Ndukwe IE, Martin GE, Williamson RT, Zweckstetter M. Bestimmung komplexer kleiner Molekülstrukturen mittels molekularer Ausrichtungssimulation. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202000311] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Alain Ibáñez de Opakua
- Translationale Strukturelle Biologie der DemenzDeutsches Zentrum für Neurodegenerative Erkrankungen (DZNE) Von-Siebold-Str. 3a 37075 Göttingen Deutschland
| | - Frederik Klama
- Abteilung für NMR-basierte StrukturbiologieMax-Planck-Institut für Biophysikalische Chemie Am Fassberg 11 37077 Göttingen Deutschland
| | - Ikenna E. Ndukwe
- Analytical Research & Development (Rahway), Merck & Co. Inc. Kenilworth NJ USA
- Complex Carbohydrate Research CenterUniversity of Georgia Athens GA 30602 USA
| | - Gary E. Martin
- Analytical Research & Development (Rahway), Merck & Co. Inc. Kenilworth NJ USA
- Department of Chemistry and BiochemistrySeton Hall University South Orange NJ 07079 USA
| | - R. Thomas Williamson
- Analytical Research & Development (Rahway), Merck & Co. Inc. Kenilworth NJ USA
- Department of Chemistry & BiochemistryUniversity of North Carolina Wilmington Wilmington NC 28409 USA
| | - Markus Zweckstetter
- Translationale Strukturelle Biologie der DemenzDeutsches Zentrum für Neurodegenerative Erkrankungen (DZNE) Von-Siebold-Str. 3a 37075 Göttingen Deutschland
- Abteilung für NMR-basierte StrukturbiologieMax-Planck-Institut für Biophysikalische Chemie Am Fassberg 11 37077 Göttingen Deutschland
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33
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Lesot P, Aroulanda C, Berdagué P, Meddour A, Merlet D, Farjon J, Giraud N, Lafon O. Multinuclear NMR in polypeptide liquid crystals: Three fertile decades of methodological developments and analytical challenges. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2020; 116:85-154. [PMID: 32130960 DOI: 10.1016/j.pnmrs.2019.10.001] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Accepted: 10/24/2019] [Indexed: 06/10/2023]
Abstract
NMR spectroscopy of oriented samples makes accessible residual anisotropic intramolecular NMR interactions, such as chemical shift anisotropy (RCSA), dipolar coupling (RDC), and quadrupolar coupling (RQC), while preserving high spectral resolution. In addition, in a chiral aligned environment, enantiomers of chiral molecules or enantiopic elements of prochiral compounds adopt different average orientations on the NMR timescale, and hence produce distinct NMR spectra or signals. NMR spectroscopy in chiral aligned media is a powerful analytical tool, and notably provides unique information on (pro)chirality analysis, natural isotopic fractionation, stereochemistry, as well as molecular conformation and configuration. Significant progress has been made in this area over the three last decades, particularly using polypeptide-based chiral liquid crystals (CLCs) made of organic solutions of helically chiral polymers (as PBLG) in organic solvents. This review presents an overview of NMR in polymeric LCs. In particular, we describe the theoretical tools and the major NMR methods that have been developed and applied to study (pro)chiral molecules dissolved in such oriented solvents. We also discuss the representative applications illustrating the analytical potential of this original NMR tool. This overview article is dedicated to thirty years of original contributions to the development of NMR spectroscopy in polypeptide-based chiral liquid crystals.
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Affiliation(s)
- Philippe Lesot
- Université Paris Sud/Université Paris-Saclay, UMR CNRS 8182, Institut de Chimie Moléculaire et des Matériaux d'Orsay, ICMMO, Equipe RMN en Milieu Orienté, Bât. 410, 15 rue du Doyen Georges Poitou, F-91405 Orsay cedex, France; Centre National de la Recherche Scientifique (CNRS), France.
| | - Christie Aroulanda
- Université Paris Sud/Université Paris-Saclay, UMR CNRS 8182, Institut de Chimie Moléculaire et des Matériaux d'Orsay, ICMMO, Equipe RMN en Milieu Orienté, Bât. 410, 15 rue du Doyen Georges Poitou, F-91405 Orsay cedex, France
| | - Philippe Berdagué
- Université Paris Sud/Université Paris-Saclay, UMR CNRS 8182, Institut de Chimie Moléculaire et des Matériaux d'Orsay, ICMMO, Equipe RMN en Milieu Orienté, Bât. 410, 15 rue du Doyen Georges Poitou, F-91405 Orsay cedex, France
| | - Abdelkrim Meddour
- Université Paris Sud/Université Paris-Saclay, UMR CNRS 8182, Institut de Chimie Moléculaire et des Matériaux d'Orsay, ICMMO, Equipe RMN en Milieu Orienté, Bât. 410, 15 rue du Doyen Georges Poitou, F-91405 Orsay cedex, France
| | - Denis Merlet
- Université Paris Sud/Université Paris-Saclay, UMR CNRS 8182, Institut de Chimie Moléculaire et des Matériaux d'Orsay, ICMMO, Equipe RMN en Milieu Orienté, Bât. 410, 15 rue du Doyen Georges Poitou, F-91405 Orsay cedex, France
| | - Jonathan Farjon
- Centre National de la Recherche Scientifique (CNRS), France; Faculté des Sciences et Techniques de Nantes, UMR CNRS 6230, Chimie et Interdisciplinarité, Synthèse, Analyse, Modélisation, CEISAM, Equipe EBSI, BP 92208, 2 rue de la Houssinière, F-44322 Nantes cedex 3, France
| | - Nicolas Giraud
- Université Paris Descartes, Sorbonne Paris Cité, UMR CNRS 8601, Laboratory of Pharmacological and Toxicological Chemistry and Biochemistry, LPTCB, 45 rue des Saints Pères, F-75006 Paris, France
| | - Olivier Lafon
- Universite de Lille, CNRS, Centrale Lille, ENSCL, Univ. Artois, UMR CNRS 8181, Unité de Catalyse et Chimie du Solide, UCCS, F-59000 Lille, France; Institut Universitaire de France (IUF), France
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34
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Knowles SL, Vu N, Todd DA, Raja HA, Rokas A, Zhang Q, Oberlies NH. Orthogonal Method for Double-Bond Placement via Ozone-Induced Dissociation Mass Spectrometry (OzID-MS). JOURNAL OF NATURAL PRODUCTS 2019; 82:3421-3431. [PMID: 31823607 PMCID: PMC7004233 DOI: 10.1021/acs.jnatprod.9b00787] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Most often, the structures of secondary metabolites are solved using a suite of NMR techniques. However, there are times when it can be challenging to position double bonds, particularly those that are fully substituted or when there are multiple double bonds in similar chemical environments. Ozone-induced dissociation mass spectrometry (OzID-MS) serves as an orthogonal structure elucidation tool, using predictable fragmentation patterns that are generated after ozonolysis across a carbon-carbon double bond. This technique is finding growing use in the lipidomics community, suggestive of its potential value for secondary metabolites. This methodology was evaluated by confirming the double-bond positions in five fungal secondary metabolites, specifically, ent-sartorypyrone E (1), sartorypyrone A (2), sorbicillin (3), trichodermic acid A (4), and AA03390 (5). This demonstrated its potential with a variety of chemotypes, ranging from polyketides to terpenoids and including those in both conjugated and nonconjugated polyenes. In addition, the potential of using this methodology in the context of a mixture was piloted by studying Aspergillus fischeri, first examining a traditional extract and then sampling a live fungal culture in situ. While the intensity of signals varied from pure compound to extract to in situ, the utility of the technique was preserved.
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Affiliation(s)
- Sonja L. Knowles
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC 27412
| | - Ngoc Vu
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC 27412
| | - Daniel A. Todd
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC 27412
| | - Huzefa A. Raja
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC 27412
| | - Antonis Rokas
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, 37235
| | - Qibin Zhang
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC 27412
- Center for Translational Biomedical Research, University of North Carolina at Greensboro, Kannapolis, NC 28081
| | - Nicholas H. Oberlies
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC 27412
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Yan P, Li G, Wang C, Wu J, Sun Z, Martin GE, Wang X, Reibarkh M, Saurí J, Gustafson KR. Characterization by Empirical and Computational Methods of Dictyospiromide, an Intriguing Antioxidant Alkaloid from the Marine Alga Dictyota coriacea. Org Lett 2019; 21:7577-7581. [PMID: 31539931 PMCID: PMC7487124 DOI: 10.1021/acs.orglett.9b02856] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The challenging structural motif of dictyospiromide (1), a spirosuccinimide alkaloid with antioxidant properties that are associated with activation of the Nrf2/ARE signaling pathway, was assigned using contemporary NMR experiments complemented with anisotropic NMR, chiroptical, and computational methodologies. Anisotropic NMR parameters provided critical orthogonal verification of the configuration of the difficult to assign spiro carbon and the other stereogenic centers in 1.
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Affiliation(s)
- Pengcheng Yan
- School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, People’s Republic of China
| | - Ge Li
- School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, People’s Republic of China
| | - Chaojie Wang
- School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, People’s Republic of China
| | - Jianzhang Wu
- School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, People’s Republic of China
| | - Zhongmin Sun
- Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, People’s Republic of China
| | - Gary E. Martin
- Department of Chemistry and Biochemistry, Seton Hall University, South Orange, New Jersey 07079, United States
| | - Xiao Wang
- Structure Elucidation Group, Analytical Research and Development, Merck & Co., Rahway, New Jersey 07065, United States
| | - Mikhail Reibarkh
- Structure Elucidation Group, Analytical Research and Development, Merck & Co., Rahway, New Jersey 07065, United States
| | - Josep Saurí
- Structure Elucidation Group, Analytical Research and Development, Merck & Co., Boston, Massachusetts 02115, United States
| | - Kirk R. Gustafson
- Molecular Targets Program, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702, United States
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36
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Abstract
Many natural products have been used as drugs for the treatment of diverse indications. Although most U.S. pharmaceutical companies have reduced or eliminated their in-house natural-product research over the years, new approaches for compound screening and chemical synthesis are resurrecting interest in exploring the therapeutic value of natural products. The aim of this commentary is to review emerging strategies and techniques that have made natural products a viable strategic choice for inclusion in drug discovery programs. Published 2019. U.S. Government.
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Affiliation(s)
- John A Beutler
- Molecular Targets Program, Center for Cancer Research, National Cancer Institute, Frederick, Maryland
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37
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Figuerola B, Avila C. The Phylum Bryozoa as a Promising Source of Anticancer Drugs. Mar Drugs 2019; 17:E477. [PMID: 31426556 PMCID: PMC6722838 DOI: 10.3390/md17080477] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 08/14/2019] [Accepted: 08/15/2019] [Indexed: 12/31/2022] Open
Abstract
Recent advances in sampling and novel techniques in drug synthesis and isolation have promoted the discovery of anticancer agents from marine organisms to combat this major threat to public health worldwide. Bryozoans, which are filter-feeding, aquatic invertebrates often characterized by a calcified skeleton, are an excellent source of pharmacologically interesting compounds including well-known chemical classes such as alkaloids and polyketides. This review covers the literature for secondary metabolites isolated from marine cheilostome and ctenostome bryozoans that have shown potential as cancer drugs. Moreover, we highlight examples such as bryostatins, the most known class of marine-derived compounds from this animal phylum, which are advancing through anticancer clinical trials due to their low toxicity and antineoplastic activity. The bryozoan antitumor compounds discovered until now show a wide range of chemical diversity and biological activities. Therefore, more research focusing on the isolation of secondary metabolites with potential anticancer properties from bryozoans and other overlooked taxa covering wider geographic areas is needed for an efficient bioprospecting of natural products.
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Affiliation(s)
- Blanca Figuerola
- Institute of Marine Sciences (ICM-CSIC), Pg. Marítim de la Barceloneta 37-49, Barcelona 08003, Catalonia, Spain.
| | - Conxita Avila
- Department of Evolutionary Biology, Ecology, and Environmental Sciences, and Biodiversity Research Institute (IrBIO), Faculty of Biology, University of Barcelona, Av. Diagonal 643, Barcelona 08028, Catalonia, Spain
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38
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Kang U, Caldwell DR, Cartner LK, Wang D, Kim CK, Tian X, Bokesch HR, Henrich CJ, Woldemichael GM, Schnermann MJ, Gustafson KR. Elucidation of Spirodactylone, a Polycyclic Alkaloid from the Sponge Dactylia sp., and Nonenzymatic Generation from the Co-metabolite Denigrin B. Org Lett 2019; 21:4750-4753. [PMID: 31150264 PMCID: PMC8274939 DOI: 10.1021/acs.orglett.9b01636] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Spirodactylone (1), a hexacyclic indolizidone alkaloid possessing a novel spiro ring system, was isolated from the marine sponge Dactylia sp. The structure was elucidated by extensive spectroscopic methods including application of the LR-HSQMBC NMR pulse sequence. Oxidative cyclization of denigrin B (2), an aryl-substituted 2-oxo-pyrroline derivative that was also isolated from the sponge extract, provided material identical to spirodactylone (1). This confirmed the assigned structure and provides insight into the probable biogenesis of 1.
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Affiliation(s)
- Unwoo Kang
- Molecular Targets Program, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702-1201, United States
| | - Donald R. Caldwell
- Chemical Biology Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702-1201, United States
| | - Laura K. Cartner
- Molecular Targets Program, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702-1201, United States
- Basic Science Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research sponsored by the National Cancer Institute, Frederick, Maryland 21702-1201, United States
| | - Dongdong Wang
- Molecular Targets Program, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702-1201, United States
| | - Chang-Kwon Kim
- Molecular Targets Program, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702-1201, United States
| | - Xiangrong Tian
- Molecular Targets Program, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702-1201, United States
- Research & Development Center of Biorational Pesticide, College of Plant Protection, Northwest A&F University, Yangling 712100, P. R. China
| | - Heidi R. Bokesch
- Molecular Targets Program, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702-1201, United States
- Basic Science Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research sponsored by the National Cancer Institute, Frederick, Maryland 21702-1201, United States
| | - Curtis J. Henrich
- Molecular Targets Program, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702-1201, United States
- Basic Science Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research sponsored by the National Cancer Institute, Frederick, Maryland 21702-1201, United States
| | - Girma M. Woldemichael
- Molecular Targets Program, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702-1201, United States
- Basic Science Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research sponsored by the National Cancer Institute, Frederick, Maryland 21702-1201, United States
| | - Martin J. Schnermann
- Chemical Biology Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702-1201, United States
| | - Kirk R. Gustafson
- Molecular Targets Program, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702-1201, United States
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Ndukwe IE, Brunskill A, Gauthier DR, Zhong YL, Martin GE, Williamson RT, Reibarkh M, Liu Y. 13C NMR-Based Approaches for Solving Challenging Stereochemical Problems. Org Lett 2019; 21:4072-4076. [PMID: 31117703 DOI: 10.1021/acs.orglett.9b01248] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Determining the configuration of proton-deficient molecules is challenging using conventional NMR methods including nuclear Overhauser effect (NOE) and the proton-dependent J-based configuration analysis (JBCA). The problem is exacerbated when only one stereoisomer is available. Alternative methods based on the utilization of 13C NMR chemical shifts, 13C-13C homonuclear couplings measured at natural abundance, and residual chemical shift anisotropy measurements in conjunction with density functional theory calculations are illustrated with a proton-deficient model compound.
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Affiliation(s)
- Ikenna E Ndukwe
- Analytical Research & Development , Merck & Co. Inc. , Rahway , New Jersey 07065 , United States
| | - Andrew Brunskill
- Analytical Research & Development , Merck & Co. Inc. , Rahway , New Jersey 07065 , United States
| | - Donald R Gauthier
- Analytical Research & Development , Merck & Co. Inc. , Rahway , New Jersey 07065 , United States
| | - Yong-Li Zhong
- Analytical Research & Development , Merck & Co. Inc. , Rahway , New Jersey 07065 , United States
| | - Gary E Martin
- Analytical Research & Development , Merck & Co. Inc. , Rahway , New Jersey 07065 , United States
| | - R Thomas Williamson
- Analytical Research & Development , Merck & Co. Inc. , Rahway , New Jersey 07065 , United States
| | - Mikhail Reibarkh
- Analytical Research & Development , Merck & Co. Inc. , Rahway , New Jersey 07065 , United States
| | - Yizhou Liu
- Analytical Research & Development , Merck & Co. Inc. , Rahway , New Jersey 07065 , United States
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40
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Wu Q, Ye F, Li XL, Liang LF, Sun J, Sun H, Guo YW, Wang H. Uncommon Polyoxygenated Sesquiterpenoids from South China Sea Soft Coral Lemnalia flava. J Org Chem 2019; 84:3083-3092. [PMID: 30762361 DOI: 10.1021/acs.joc.8b02912] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A detailed chemical investigation of the Chinese soft coral Lemnalia flava yielded four new nardosinane-type sesquiterpenoids (1-4), one new neolemnane-type sesquiterpenoid (5), and one new sesquiterpenoid with an uncommon 6/9 fused bicyclic skeleton (6), together with two known related compounds (7 and 8). The structures and absolute configurations of 1-8 were determined on the basis of extensive spectroscopic data analyses, X-ray diffraction analysis, chemical reactions, and computer-assisted structural elucidation including 13C NMR data calculation, residual dipolar coupling based NMR analysis, and time-dependent density functional theoryelectronic circular dichroism calculation. Plausible biogenetic pathways of two uncommon sesquiterpenoids (4 and 6) were proposed.
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Affiliation(s)
- Qihao Wu
- College of Pharmaceutical Science & Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals , Zhejiang University of Technology , Hangzhou , China.,State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica , Chinese Academy of Sciences , 555 Zu Chong Zhi Road , Zhangjiang Hi-Tech Park, Shanghai 201203 , China
| | - Fei Ye
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica , Chinese Academy of Sciences , 555 Zu Chong Zhi Road , Zhangjiang Hi-Tech Park, Shanghai 201203 , China
| | - Xiao-Lu Li
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) , Robert-Rössle-Str. 10 , Berlin 13125 , Germany
| | - Lin-Fu Liang
- College of Material Science and Engineering , Central South University of Forestry and Technology , Changsha 410004 , China
| | - Jiadong Sun
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) , National Institutes of Health , Bethesda , Maryland 20892 , United States
| | - Han Sun
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) , Robert-Rössle-Str. 10 , Berlin 13125 , Germany
| | - Yue-Wei Guo
- College of Pharmaceutical Science & Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals , Zhejiang University of Technology , Hangzhou , China.,State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica , Chinese Academy of Sciences , 555 Zu Chong Zhi Road , Zhangjiang Hi-Tech Park, Shanghai 201203 , China
| | - Hong Wang
- College of Pharmaceutical Science & Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals , Zhejiang University of Technology , Hangzhou , China
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41
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Yang M, Li XL, Wang JR, Lei X, Tang W, Li XW, Sun H, Guo YW. Sarcomililate A, an Unusual Diterpenoid with Tricyclo[11.3.0.02,16]hexadecane Carbon Skeleton, and Its Potential Biogenetic Precursors from the Hainan Soft Coral Sarcophyton mililatensis. J Org Chem 2019; 84:2568-2576. [DOI: 10.1021/acs.joc.8b03020] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Min Yang
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zu Chong Zhi Road, Zhangjiang Hi-Tech Park, Shanghai 201203, P. R. China
- University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing 100049, P. R. China
| | - Xiao-Lu Li
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Rössle-Str. 10, Berlin 13125, Germany
| | - Jian-Rong Wang
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zu Chong Zhi Road, Zhangjiang Hi-Tech Park, Shanghai 201203, P. R. China
| | - Xinxiang Lei
- School of Pharmaceutical Sciences, South Central University for Nationalities, Wuhan 430074, P. R. China
| | - Wei Tang
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zu Chong Zhi Road, Zhangjiang Hi-Tech Park, Shanghai 201203, P. R. China
| | - Xu-Wen Li
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zu Chong Zhi Road, Zhangjiang Hi-Tech Park, Shanghai 201203, P. R. China
- University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing 100049, P. R. China
| | - Han Sun
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Rössle-Str. 10, Berlin 13125, Germany
| | - Yue-Wei Guo
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zu Chong Zhi Road, Zhangjiang Hi-Tech Park, Shanghai 201203, P. R. China
- University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing 100049, P. R. China
- College of Pharmaceutical Sciences, Zhejiang University of Technology, Hangzhou 310014, P. R. China
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42
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Application of anisotropic NMR parameters to the confirmation of molecular structure. Nat Protoc 2018; 14:217-247. [DOI: 10.1038/s41596-018-0091-9] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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43
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Di Micco S, Giannini C, Previtali A, Lucenti E, Bifulco G. Chemical shift assignment of mono- and di-bromo triimidazo[1,2-a:1',2'-c:1″,2″-e][1,3,5]triazine derivatives by DFT/NMR integrated approach. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2018; 57:82-92. [PMID: 30421826 DOI: 10.1002/mrc.4804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 10/19/2018] [Accepted: 10/31/2018] [Indexed: 06/09/2023]
Abstract
Mono- and di-bromo derivatives of triimidazo[1,2-a:1',2'-c:1″,2″-e][1,3,5]triazine have been proposed as new organic molecules presenting a very rich and complex photophysical behavior. Thus, we afforded the correct chemical shift assignment by integrating the experimental data with DFT calculation of NMR parameters. Our findings lay foundation for a structural reference in the organic synthesis and characterization of new congeners of this intriguing class of molecules.
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Affiliation(s)
- Simone Di Micco
- Department of Pharmacy, University of Salerno, Fisciano (SA), Italy
| | - Clelia Giannini
- Department of Chemistry, Università degli Studi di Milano, Milan, Italy
| | - Andrea Previtali
- Department of Chemistry, Università degli Studi di Milano, Milan, Italy
| | - Elena Lucenti
- ISTM-CNR, Institute of Molecular Science and Technologies, INSTM RU, National Interuniversity Consortium of Material Science and Technology, Milan, Italy
| | - Giuseppe Bifulco
- Department of Pharmacy, University of Salerno, Fisciano (SA), Italy
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44
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Li GW, Liu H, Qiu F, Wang XJ, Lei XX. Residual Dipolar Couplings in Structure Determination of Natural Products. NATURAL PRODUCTS AND BIOPROSPECTING 2018; 8:279-295. [PMID: 29943349 PMCID: PMC6102172 DOI: 10.1007/s13659-018-0174-x] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Accepted: 06/14/2018] [Indexed: 05/16/2023]
Abstract
The determination of natural products stereochemistry remains a formidable task. Residual dipolar couplings (RDCs) induced by anisotropic media are a powerful tool for determination of the stereochemistry of organic molecule in solution. This review will provide a short introduction on RDCs-based methodology for the structural elucidation of natural products. Special attention is given to the current availability of alignment media in organic solvents. The applications of RDCs for structural analysis of some examples of natural products were discussed and summarized. This review provides a short introduction on RDCs-based methodology for the structural elucidation of natural products. Special attention is given to the current availability of alignment media in organic solvents. The applications of RDCs for structural analysis of some examples of natural products were discussed and summarized.
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Affiliation(s)
- Gao-Wei Li
- College of Chemistry and Chemical Engineering, Shangqiu Normal University, Shangqiu, 476000, People's Republic of China
| | - Han Liu
- School of Pharmaceutical Sciences, South Central University for Nationalities, Wuhan, 430074, People's Republic of China
| | - Feng Qiu
- School of Pharmaceutical Sciences, South Central University for Nationalities, Wuhan, 430074, People's Republic of China
| | - Xiao-Juan Wang
- College of Chemistry and Chemical Engineering, Shangqiu Normal University, Shangqiu, 476000, People's Republic of China
| | - Xin-Xiang Lei
- School of Pharmaceutical Sciences, South Central University for Nationalities, Wuhan, 430074, People's Republic of China.
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45
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Kim HY, Saurí J, Cohen RD, Martin GE. Observation of untoward 3 J cc correlations in 1,1-ADEQUATE spectra of pyrimidine analogs: Avoiding potential interpretation pitfalls. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2018; 56:775-781. [PMID: 29603782 DOI: 10.1002/mrc.4736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 03/19/2018] [Accepted: 03/20/2018] [Indexed: 06/08/2023]
Abstract
Recently, it has been reported that large n JCC correlations can sometimes be observed in 1,1-ADEQUATE spectra with significant intensity, which opens the possibility of structural misassignment. In this work, we have focused on pyrimidine-based compounds, which exhibit multiple bond correlations in the 1,1-ADEQUATE experiment as a consequence of 3 JCC coupling constants greater than 10 Hz. Results are supported by both the experimental measurement of 3 JCC coupling constants in question using J-modulated-ADEQUATE and density functional theory calculations.
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Affiliation(s)
- Hai-Young Kim
- Structure Elucidation Group, Process and Analytical Research and Development, Merck & Co., Inc., 33 Avenue Louis Pasteur, Boston, MA, 02115, USA
| | - Josep Saurí
- Structure Elucidation Group, Process and Analytical Research and Development, Merck & Co., Inc., 33 Avenue Louis Pasteur, Boston, MA, 02115, USA
| | - Ryan D Cohen
- Structure Elucidation Group, Process and Analytical Research and Development, Merck & Co., Inc., P.O. Box 2000, Rahway, NJ, 07065, USA
| | - Gary E Martin
- Structure Elucidation Group, Process and Analytical Research and Development, Merck & Co., Inc., P.O. Box 2000, Rahway, NJ, 07065, USA
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46
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Liu Y, Cohen RD, Martin GE, Williamson RT. A practical strategy for the accurate measurement of residual dipolar couplings in strongly aligned small molecules. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2018; 291:63-72. [PMID: 29723716 DOI: 10.1016/j.jmr.2018.04.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 04/05/2018] [Accepted: 04/05/2018] [Indexed: 06/08/2023]
Abstract
Accurate measurement of residual dipolar couplings (RDCs) requires an appropriate degree of alignment in order to optimize data quality. An overly weak alignment yields very small anisotropic data that are susceptible to measurement errors, whereas an overly strong alignment introduces extensive anisotropic effects that severely degrade spectral quality. The ideal alignment amplitude also depends on the specific pulse sequence used for the coupling measurement. In this work, we introduce a practical strategy for the accurate measurement of one-bond 13C-1H RDCs up to a range of ca. -300 to +300 Hz, corresponding to an alignment that is an order of magnitude stronger than typically employed for small molecule structural elucidation. This strong alignment was generated in the mesophase of the commercially available poly-γ-(benzyl-L-glutamate) polymer. The total coupling was measured by the simple and well-studied heteronuclear two-dimensional J-resolved experiment, which performs well in the presence of strong anisotropic effects. In order to unequivocally determine the sign of the total coupling and resolve ambiguities in assigning total couplings in the CH2 group, coupling measurements were conducted at an isotropic condition plus two anisotropic conditions of different alignment amplitudes. Most RDCs could be readily extracted from these measurements whereas more complicated spectral effects resulting from strong homonuclear coupling could be interpreted either theoretically or by simulation. Importantly, measurement of these very large RDCs actually offers significantly improved data quality and utility for the structure determination of small organic molecules.
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Affiliation(s)
- Yizhou Liu
- Structure Elucidation Group, Process and Analytical Research and Development, Merck & Co. Inc., 126 East Lincoln Avenue, Rahway, NJ 07065, USA.
| | - Ryan D Cohen
- Structure Elucidation Group, Process and Analytical Research and Development, Merck & Co. Inc., 126 East Lincoln Avenue, Rahway, NJ 07065, USA
| | - Gary E Martin
- Structure Elucidation Group, Process and Analytical Research and Development, Merck & Co. Inc., 126 East Lincoln Avenue, Rahway, NJ 07065, USA
| | - R Thomas Williamson
- Structure Elucidation Group, Process and Analytical Research and Development, Merck & Co. Inc., 126 East Lincoln Avenue, Rahway, NJ 07065, USA
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47
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Review of bioactive secondary metabolites from marine bryozoans in the progress of new drugs discovery. Future Med Chem 2018; 10:1497-1514. [PMID: 29788787 DOI: 10.4155/fmc-2018-0012] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Marine bryozoans play an important role for the discovery of novel bioactive compounds among marine organisms. In this review, we summarize 164 new secondary metabolites including macrocyclic lactones, sterols, alkaloids, sphingolipids and so forth from 24 marine bryozoans in the last two decades. The structural features, bioactivity, structure-activity relationship, mechanism and strategies to address the resupply of these scarce secondary metabolites are discussed. The structural and bioactive diversity of the secondary metabolites from marine bryozoans indicated the possibility of using these compounds, especially bryostatin 1 (1), bryostatin analog (BA1), alkaloids (50, 53, 127-128 and 134-139), sphingolipids sulfates (148 and 149) and sulfur-containing aromatic compound (160), as the starting points for new drug discovery.
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Caytan E, Ligny R, Carpentier JF, Guillaume SM. Evaluation of Band-Selective HSQC and HMBC: Methodological Validation on the Cyclosporin Cyclic Peptide and Application for Poly(3-hydroxyalkanoate)s Stereoregularity Determination. Polymers (Basel) 2018; 10:E533. [PMID: 30966567 PMCID: PMC6415406 DOI: 10.3390/polym10050533] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 05/09/2018] [Accepted: 05/15/2018] [Indexed: 01/20/2023] Open
Abstract
Band-selective (bs) HSQC, improving spectral resolution by restriction of the heteronuclear dimension without inducing spectral folding, has been recently used for polymer tacticity determination. Herein is reported an evaluation of various bs-HSQC and bs-HMBC sequences, first from a methodological point of view (selectivity, dependence to INEPT interpulse delay or relaxation delay), using the cyclic peptide cyclosporin selected as a model compound, and then from an applicative approach, comparing tacticity determined from bs-HSQC and bs-HMBC experiments to the one obtained from 1D 13C{¹H} on poly(3-hydroxyalkanoate)s samples. For HSQC sequences, the 13C selectivity scheme consisting in substituting a 13C broadband refocalization by a selective one revealed itself problematic, with unwanted aliased signals, whereas the insertion of double pulsed field gradients spin-echo (DPFGSE) or the use of opposite sign gradients bracketing a selective refocalization gave satisfactory results. Determination of the probability of syndiotactic enchainments, Ps, by bs-HSQC is fully consistent and no precision loss was observed when decreasing acquisition time (37 min vs. 106 min for 1D 13C{¹H}). Bs-HMBC, although not straightforwardly applicable for tacticity determination, could provide (after a calibration step) an alternative for compounds of which only 13C carbonyl signals are resolved enough for discriminating between syndiotactic and isotactic configurations.
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Affiliation(s)
- Elsa Caytan
- Univ Rennes, CNRS, Institut des Sciences Chimiques de Rennes-UMR6226, F-35000 Rennes, France.
| | - Romain Ligny
- Univ Rennes, CNRS, Institut des Sciences Chimiques de Rennes-UMR6226, F-35000 Rennes, France.
| | | | - Sophie M Guillaume
- Univ Rennes, CNRS, Institut des Sciences Chimiques de Rennes-UMR6226, F-35000 Rennes, France.
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Marcó N, Gil RR, Parella T. Isotropic/Anisotropic NMR Editing by Resolution-Enhanced NMR Spectroscopy. Chemphyschem 2018; 19:1024-1029. [PMID: 29384256 DOI: 10.1002/cphc.201800094] [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: 01/30/2018] [Indexed: 11/11/2022]
Abstract
Modern resolution-enhanced NMR techniques can monitor the in situ discrimination of co-existing isotropic and anisotropic contributions of small molecules dissolved in weakly aligning PMMA/CDCl3 media. The simultaneous sign-sensitive determination of accurate Δδiso-aniso (1 H), Δδiso-aniso (13 C) and/or isotropic 1 JCH and anisotropic 1 TCH coupling constants (and consequently 1 H-13 C residual dipolar couplings and 1 H/13 C residual chemical shift anisotropies) can be performed from spectral-aliased heteronuclear single-quantum correlation spectra.
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Affiliation(s)
- Núria Marcó
- Servei de Ressonància Magnètica Nuclear, Universitat Autònoma de Barcelona, 08193, Bellaterra, Catalonia, Spain
| | - Roberto R Gil
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, 15213, PA, USA
| | - Teodor Parella
- Servei de Ressonància Magnètica Nuclear, Universitat Autònoma de Barcelona, 08193, Bellaterra, Catalonia, Spain
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