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Fuentes-Monteverde JC, Noll M, Das A, Immel S, Reggelin M, Griesinger C, Nath N. Residual-Chemical-Shift-Anisotropy-Based Enantiodifferentiation in Lyotropic Liquid Crystalline Phases Based on Helically Chiral Polyacetylenes. Angew Chem Int Ed Engl 2023; 62:e202309981. [PMID: 37684219 DOI: 10.1002/anie.202309981] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 08/25/2023] [Accepted: 09/06/2023] [Indexed: 09/10/2023]
Abstract
Anisotropic NMR spectroscopy, revealing residual dipolar couplings (RDCs) and residual chemical shift anisotropies (RCSAs) has emerged as a powerful tool to determine the configurations of synthetic and complex natural compounds. The deduction of the absolute in addition to the relative configuration is one of the primary goals in the field. Therefore, the investigation of the enantiodiscriminating capabilities of chiral alignment media becomes essential. While RDCs and RCSAs are now used for the determination of the relative configuration routinely, RCSAs have not been measured in chiral alignment media such as chiral liquid crystals. Herein, we present this application by measuring RCSAs for chiral analytes such as indanol and isopinocampheol in the lyotropic liquid crystalline phase of an L-valine derived helically chiral polyacetylenes. We have also demonstrated that a single 1D 13 C-{1 H} NMR spectrum suffices to get the RCSAs circumventing the necessity to acquire two spectra at two alignment conditions.
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Affiliation(s)
- Juan Carlos Fuentes-Monteverde
- Max Planck Institute for Multidisciplinary Sciences, Department of NMR-Based Structural Biology, Am Fassberg 11, 37077, Göttingen, Germany
| | - Markus Noll
- Department of Chemistry, Technical University of Darmstadt, Alarich Weiss Straße 4, 64287, Darmstadt, Germany
| | - Akhi Das
- Department of Chemistry, Gauhati University Guwahati, Jalukbari, 781014, India
| | - Stefan Immel
- Department of Chemistry, Technical University of Darmstadt, Alarich Weiss Straße 4, 64287, Darmstadt, Germany
| | - Michael Reggelin
- Department of Chemistry, Technical University of Darmstadt, Alarich Weiss Straße 4, 64287, Darmstadt, Germany
| | - Christian Griesinger
- Max Planck Institute for Multidisciplinary Sciences, Department of NMR-Based Structural Biology, Am Fassberg 11, 37077, Göttingen, Germany
| | - Nilamoni Nath
- Department of Chemistry, Gauhati University Guwahati, Jalukbari, 781014, India
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2
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Wesp S, Wolf K, Immel S, Reggelin M. Poly(arylisocyanides) as Versatile, Enantiodiscriminating Alignment Media for Small Molecules. Chempluschem 2022; 87:e202100507. [PMID: 35072980 DOI: 10.1002/cplu.202100507] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 01/02/2022] [Indexed: 11/08/2022]
Abstract
Lyotropic liquid crystalline (LLC) phases of amino acid derived polyarylisocyanides were employed as chiral alignment media for the measurement of residual dipolar couplings (RDCs) of small chiral organic molecules. Anisotropic samples in CDCl3 displayed quadrupolar splittings of the deuterium signal in the range of several hundreds of Hertz. The LLC phases showed excellent orienting properties for a broad range of analytes bearing various functional groups. The precise extraction of RDCs in the range of up to ±40 Hertz from F2-coupled HSQC spectra was possible. Additionally, the chiral environment offers the opportunity for diastereomorphous interactions with the enantiomers of chiral analytes leading to two different sets of RDCs. This differential order effect was particularly pronounced with ketones and alcohols.
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Affiliation(s)
- Svenja Wesp
- Technische Universität Darmstadt, Clemens Schöpf Institut für Organische Chemie und Biochemie, Alarich-Weiss-Str. 4, 64287, Darmstadt, Germany
| | - Kai Wolf
- Technische Universität Darmstadt, Clemens Schöpf Institut für Organische Chemie und Biochemie, Alarich-Weiss-Str. 4, 64287, Darmstadt, Germany
| | - Stefan Immel
- Technische Universität Darmstadt, Clemens Schöpf Institut für Organische Chemie und Biochemie, Alarich-Weiss-Str. 4, 64287, Darmstadt, Germany
| | - Michael Reggelin
- Technische Universität Darmstadt, Clemens Schöpf Institut für Organische Chemie und Biochemie, Alarich-Weiss-Str. 4, 64287, Darmstadt, Germany
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3
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Chiliveri SC, Robertson AJ, Shen Y, Torchia DA, Bax A. Advances in NMR Spectroscopy of Weakly Aligned Biomolecular Systems. Chem Rev 2021; 122:9307-9330. [PMID: 34766756 DOI: 10.1021/acs.chemrev.1c00730] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The measurement and application of residual dipolar couplings (RDCs) in solution NMR studies of biological macromolecules has become well established over the past quarter of a century. Numerous methods for generating the requisite anisotropic orientational molecular distribution have been demonstrated, each with its specific strengths and weaknesses. In parallel, an enormous number of pulse schemes have been introduced to measure the many different types of RDCs, ranging from the most widely measured backbone amide 15N-1H RDCs, to 1H-1H RDCs and couplings between low-γ nuclei. Applications of RDCs range from structure validation and refinement to the determination of relative domain orientations, the measurement of backbone and domain motions, and de novo structure determination. Nevertheless, it appears that the power of the RDC methodology remains underutilized. This review aims to highlight the practical aspects of sample preparation and RDC measurement while describing some of the most straightforward applications that take advantage of the exceptionally precise information contained in such data. Some emphasis will be placed on more recent developments that enable the accurate measurement of RDCs in larger systems, which is key to the ongoing shift in focus of biological NMR spectroscopy from structure determination toward gaining improved understanding of how molecular flexibility drives protein function.
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Affiliation(s)
- Sai Chaitanya Chiliveri
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Angus J Robertson
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Yang Shen
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Dennis A Torchia
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Ad Bax
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, United States
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4
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Sánchez-Pedregal VM, Kertesz M, Weiss RG, Navarro-Vázquez A, Cid MM. NMR spectral fingerprint patterns as diagnostics for the unambiguous configurational analysis of the classic organo-gelator 1,3:2,4-dibenzylidene-d-sorbitol (DBS) and its derivatives. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2021; 59:608-613. [PMID: 33368599 DOI: 10.1002/mrc.5124] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 12/11/2020] [Accepted: 12/17/2020] [Indexed: 06/12/2023]
Abstract
On the basis of experimental data and density functional theory (DFT) chemical shift and scalar coupling predictions, simple spectral nuclear magnetic resonance (NMR) fingerprint patterns have been established for the determination of the configuration in 1,3:2,4-dibenzylidene-d-sorbitol (DBS), a classic low molecular weight gelator, and its derivatives. The results rigorously prove the orientation of the phenyl rings in DBS that had been previously assumed in the literature on the basis of thermodynamic arguments.
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Affiliation(s)
- Víctor M Sánchez-Pedregal
- Departamento de Química Orgánica, Universidade de Santiago de Compostela, Santiago de Compostela, 15782, Spain
| | - Miklos Kertesz
- Department of Chemistry and Institute for Soft Matter Synthesis and Metrology, Georgetown University, Washington, District of Columbia, 20057-1227, USA
| | - Richard G Weiss
- Department of Chemistry and Institute for Soft Matter Synthesis and Metrology, Georgetown University, Washington, District of Columbia, 20057-1227, USA
| | - Armando Navarro-Vázquez
- Departmento de Química Fundamental, Centro de Ciências Exatas e da Natureza, Universidade Federal de Pernambuco, Recife, 50740-540, Brazil
| | - María Magdalena Cid
- Departmento de Química Orgánica and Agrupación Estratéxica CITACA, Universidade de Vigo, Vigo, 36310, Spain
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5
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Krupp A, Noll M, Reggelin M. Valine derived poly (acetylenes) as versatile chiral lyotropic liquid crystalline alignment media for RDC-based structure elucidations. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2021; 59:577-586. [PMID: 32012341 DOI: 10.1002/mrc.5003] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 01/22/2020] [Accepted: 01/27/2020] [Indexed: 06/10/2023]
Abstract
Anisotropic samples of lyotropic liquid crystalline (LLC) phases of valine derived polyaryl acetylenes were employed as chiral alignment media for the measurement of residual dipolar couplings (RDCs) of 12 small, chiral, organic molecules. The quadrupolar splitting of the deuterium signal of CDCl3 can be adjusted by temperature and concentration changes from 0 to 350 Hz. The LLC phases showed excellent orienting properties for all analytes bearing various functional groups. The precise extraction of RDCs in the range of up to ±30 Hz from F2-coupled HSQC spectra was possible. Additionally, the chiral environment led to diastereomorphous interactions with the enantiomers of chiral analytes leading to two different sets of RDCs. This differential order effect was particularly pronounced with H-bond donors like alcohols and 2° amines.
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Affiliation(s)
- Alexis Krupp
- Clemens Schöpf Institut for Organic Chemistry and Biochemistry, Technical University of Darmstadt, Darmstadt, Germany
- Nitrochemie Aschau GmbH, Aschau am Inn, Germany
| | - Markus Noll
- Clemens Schöpf Institut for Organic Chemistry and Biochemistry, Technical University of Darmstadt, Darmstadt, Germany
| | - Michael Reggelin
- Clemens Schöpf Institut for Organic Chemistry and Biochemistry, Technical University of Darmstadt, Darmstadt, Germany
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6
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Das A, Nath N. Elucidating natural product structures using a robust measurement of carbon residual chemical shift anisotropy combined with DFT. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2021; 59:569-576. [PMID: 31758720 DOI: 10.1002/mrc.4975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Revised: 08/20/2019] [Accepted: 08/31/2019] [Indexed: 06/10/2023]
Abstract
Determination of configurations and conformations is an important step in the structural characterization of small molecules. Apart from utilizing isotropic J-couplings and nuclear overhauser effect (NOEs) measured in isotropic solution, anisotropic Nuclear Magnetic resonance (NMR) data such as residual dipolar couplings and residual chemical shift anisotropies (RCSAs) were also used to elucidate complex small molecule structures. Measuring RCSA has always been historically difficult due to the isotropic shift effect accompanied by molecular alignment and therefore only occasionally applied in a few examples. Here, we present a robust measurement of carbon RCSAs using a smaller gel-stretching device to determine the structures of a few small molecules. A systematic study on how different density functional theory computed anisotropies of the chemical shift anisotropy tensors impact RCSA data interpretation has also been discussed. We also discuss the effect of utilizing various carbons as reference nuclei for RCSA data extraction as well as the orientation behavior of estrone in orthogonal alignment media.
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Affiliation(s)
- Akhi Das
- Department of Chemistry, Gauhati University, Guwahati, India
| | - Nilamoni Nath
- Department of Chemistry, Gauhati University, Guwahati, India
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7
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Relative configuration of micrograms of natural compounds using proton residual chemical shift anisotropy. Nat Commun 2020; 11:4372. [PMID: 32873801 PMCID: PMC7463026 DOI: 10.1038/s41467-020-18093-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 07/28/2020] [Indexed: 01/12/2023] Open
Abstract
3D molecular structure determination is a challenge for organic compounds or natural products available in minute amounts. Proton/proton and proton/carbon correlations yield the constitution. J couplings and NOEs oftentimes supported by one-bond 1H,13C residual dipolar couplings (RDCs) or by 13C residual chemical shift anisotropies (RCSAs) provide the relative configuration. However, these RDCs or carbon RCSAs rely on 1% natural abundance of 13C preventing their use for compounds available only in quantities of a few 10’s of µgs. By contrast, 1H RCSAs provide similar information on spatial orientation of structural moieties within a molecule, while using the abundant 1H spin. Herein, 1H RCSAs are accurately measured using constrained aligning gels or liquid crystals and applied to the 3D structural determination of molecules with varying complexities. Even more, deuterated alignment media allow the elucidation of the relative configuration of around 35 µg of a briarane compound isolated from Briareum asbestinum. Determination of 3D molecular structures remains challenging for natural products or organic compounds available in minute amounts. Here, the authors determine the structure of complex molecules, including few micrograms of briarane B-3 isolated from Briareum asbestinums, through measurement of 1H residual chemical shift anisotropy.
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8
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Sinnaeve D, Ilgen J, Di Pietro ME, Primozic JJ, Schmidts V, Thiele CM, Luy B. Probing Long‐Range Anisotropic Interactions: a General and Sign‐Sensitive Strategy to Measure
1
H–
1
H Residual Dipolar Couplings as a Key Advance for Organic Structure Determination. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201915278] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Davy Sinnaeve
- Univ. LilleInsermInstitut Pasteur de LilleCHU LilleU1167—Labex DISTALZ—RID-AGE—Risk Factors and Molecular Determinants of Aging-Related Diseases 59000 Lille France
- CNRS, ERL9002—Integrative Structural Biology 59000 Lille France
- Department of Organic and Macromolecular ChemistryGhent University, Campus Sterre, S4 Krijgslaan 281 9000 Ghent Belgium
| | - Julian Ilgen
- Clemens-Schöpf Institut für Organische Chemie und BiochemieTechnische Universität Darmstadt Alarich-Weiss-Straße 4 64287 Darmstadt Germany
| | - Maria Enrica Di Pietro
- Institute of Organic Chemistry and Institute for Biological Interfaces 4—Magnetic ResonanceKarlsruhe Institute of Technology (KIT) Fritz-Haber-Weg 6 76131 Karlsruhe Germany
- Current address: Department of ChemistryMaterials and Chemical Engineering “Giulio Natta”Politecnico di Milano Piazza Leonardo da Vinci 32 20133 Milan Italy
| | - Johann J. Primozic
- Clemens-Schöpf Institut für Organische Chemie und BiochemieTechnische Universität Darmstadt Alarich-Weiss-Straße 4 64287 Darmstadt Germany
| | - Volker Schmidts
- Clemens-Schöpf Institut für Organische Chemie und BiochemieTechnische Universität Darmstadt Alarich-Weiss-Straße 4 64287 Darmstadt Germany
| | - Christina M. Thiele
- Clemens-Schöpf Institut für Organische Chemie und BiochemieTechnische Universität Darmstadt Alarich-Weiss-Straße 4 64287 Darmstadt Germany
| | - Burkhard Luy
- Institute of Organic Chemistry and Institute for Biological Interfaces 4—Magnetic ResonanceKarlsruhe Institute of Technology (KIT) Fritz-Haber-Weg 6 76131 Karlsruhe Germany
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9
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Sinnaeve D, Ilgen J, Di Pietro ME, Primozic JJ, Schmidts V, Thiele CM, Luy B. Probing Long-Range Anisotropic Interactions: a General and Sign-Sensitive Strategy to Measure 1 H- 1 H Residual Dipolar Couplings as a Key Advance for Organic Structure Determination. Angew Chem Int Ed Engl 2020; 59:5316-5320. [PMID: 31945235 DOI: 10.1002/anie.201915278] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Indexed: 11/10/2022]
Abstract
Residual dipolar couplings (RDCs) are amongst the most powerful NMR parameters for organic structure elucidation. In order to maximize their effectiveness in increasingly complex cases such as flexible compounds, a maximum of RDCs between nuclei sampling a large distribution of orientations is needed, including sign information. For this, the easily accessible one-bond 1 H-13 C RDCs alone often fall short. Long-range 1 H-1 H RDCs are both abundant and typically sample highly complementary orientations, but accessing them in a sign-sensitive way has been severely obstructed due to the overflow of 1 H-1 H couplings. Here, we present a generally applicable strategy that allows the measurement of a large number of 1 H-1 H RDCs, including their signs, which is based on a combination of an improved PSYCHEDELIC method and a new selective constant-time β-COSY experiment. The potential of 1 H-1 H RDCs to better determine molecular alignment and to discriminate between enantiomers and diastereomers is demonstrated.
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Affiliation(s)
- Davy Sinnaeve
- Univ. Lille, Inserm, Institut Pasteur de Lille, CHU Lille, U1167-Labex DISTALZ-RID-AGE-Risk Factors and Molecular Determinants of Aging-Related Diseases, 59000, Lille, France.,CNRS, ERL9002-Integrative Structural Biology, 59000, Lille, France.,Department of Organic and Macromolecular Chemistry, Ghent University, Campus Sterre, S4, Krijgslaan 281, 9000, Ghent, Belgium
| | - Julian Ilgen
- Clemens-Schöpf Institut für Organische Chemie und Biochemie, Technische Universität Darmstadt, Alarich-Weiss-Straße 4, 64287, Darmstadt, Germany
| | - Maria Enrica Di Pietro
- Institute of Organic Chemistry and Institute for Biological Interfaces 4-Magnetic Resonance, Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 6, 76131, Karlsruhe, Germany.,Current address: Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133, Milan, Italy
| | - Johann J Primozic
- Clemens-Schöpf Institut für Organische Chemie und Biochemie, Technische Universität Darmstadt, Alarich-Weiss-Straße 4, 64287, Darmstadt, Germany
| | - Volker Schmidts
- Clemens-Schöpf Institut für Organische Chemie und Biochemie, Technische Universität Darmstadt, Alarich-Weiss-Straße 4, 64287, Darmstadt, Germany
| | - Christina M Thiele
- Clemens-Schöpf Institut für Organische Chemie und Biochemie, Technische Universität Darmstadt, Alarich-Weiss-Straße 4, 64287, Darmstadt, Germany
| | - Burkhard Luy
- Institute of Organic Chemistry and Institute for Biological Interfaces 4-Magnetic Resonance, Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 6, 76131, Karlsruhe, Germany
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10
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Immel S, Köck M, Reggelin M. Configurational analysis by residual dipolar couplings: A critical assessment of diastereomeric differentiabilities. Chirality 2019; 31:384-400. [PMID: 30916829 DOI: 10.1002/chir.23065] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 02/20/2019] [Accepted: 02/21/2019] [Indexed: 11/06/2022]
Abstract
Two independent statistical models for evaluating the certainties of configurational assignments of compounds based on nuclear magnetic resonance (NMR) data are evaluated and compared. Both methods yield weights or probabilities with which two or more structure models (constitutional or configurational isomers or even conformers) could be differentiated based on experimental parameters. Although this paper focusses on the use of residual dipolar couplings (RDCs) for the differentiation of diastereomers, the concept can be expanded to any set of experimental NMR-derived parameters. It is demonstrated that highly reliable configurational assignments crucially must depend on thorough statistical analysis, which is frequently neglected in the literature.
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Affiliation(s)
- Stefan Immel
- Clemens Schöpf Institut für Organische Chemie und Biochemie, Technische Universität Darmstadt, Darmstadt, Germany
| | - Matthias Köck
- Alfred-Wegener-Institut (AWI), Helmholtz-Zentrum für Polar- und Meeresforschung, Sektion Ökologische Chemie, Bremerhaven, Germany.,Helmholtz-Zentrum für Infektionsforschung (HZI), Abteilung Chemische Biologie, Braunschweig, Germany
| | - Michael Reggelin
- Clemens Schöpf Institut für Organische Chemie und Biochemie, Technische Universität Darmstadt, Darmstadt, Germany
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11
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Ndukwe IE, Wang X, Pelczer I, Reibarkh M, Williamson RT, Liu Y, Martin GE. PBLG as a versatile liquid crystalline medium for anisotropic NMR data acquisition. Chem Commun (Camb) 2019; 55:4327-4330. [DOI: 10.1039/c9cc01130g] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The chiral nematic phase of poly-γ-benzyl-l-glutamate (PBLG) formed in a chloroform–DMSO co-solvent system can be used as a versatile alignment medium for the acquisition of high quality anisotropic NMR data for molecules of varying polarities.
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Affiliation(s)
- Ikenna E. Ndukwe
- Analytical Research and Development (Rahway)
- Merck & Co. Inc
- Kenilworth
- USA
| | - Xiao Wang
- Analytical Research and Development (Rahway)
- Merck & Co. Inc
- Kenilworth
- USA
| | | | - Mikhail Reibarkh
- Analytical Research and Development (Rahway)
- Merck & Co. Inc
- Kenilworth
- USA
| | | | - Yizhou Liu
- Analytical Research and Development (Rahway)
- Merck & Co. Inc
- Kenilworth
- USA
| | - Gary E. Martin
- Analytical Research and Development (Rahway)
- Merck & Co. Inc
- Kenilworth
- USA
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12
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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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13
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Kakita VMR, Hosur RV. Real-time J-upscaling in two-dimensional pure shift diagonal NMR: Simultaneous resolution enhancement in chemical shifts and scalar couplings. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2018; 296:176-180. [PMID: 30286413 DOI: 10.1016/j.jmr.2018.09.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2018] [Revised: 09/24/2018] [Accepted: 09/25/2018] [Indexed: 06/08/2023]
Abstract
A two-dimensional real-time J-upscaled pure shift diagonal pulse scheme, JS-PSYCHE-DIAG has been developed. This method enhances the resolution in scalar coupling multiplets by real-time J-upscaling during the direct acquisition, and these J-upscaled multiplets resolve on the diagonal at the respective pure shift positions, which results in resolution enhancement in chemical shifts. Thus, both chemical shifts and scalar couplings get better resolved simultaneously in the same NMR experiment. The efficacy of the present method has been demonstrated, (i) on hesperidin for resolving the J-upscaled multiplets belonging to diastereomers and (ii) on a natural product, strychnine, to measure small scalar couplings including the long range values.
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Affiliation(s)
- Veera Mohana Rao Kakita
- UM-DAE Centre for Excellence in Basic Sciences, University of Mumbai, Kalina Campus, Santacruz, Mumbai 400 098, India
| | - Ramakrishna V Hosur
- UM-DAE Centre for Excellence in Basic Sciences, University of Mumbai, Kalina Campus, Santacruz, Mumbai 400 098, India.
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14
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Lakshmi JK, Pattnaik B, Kavitha R, Mallavadhani UV, Jagadeesh B. Conformation of flexibly linked triterpene dimers by using RDC-enhanced NMR spectroscopy. J Mol Struct 2018. [DOI: 10.1016/j.molstruc.2018.02.083] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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15
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Nuzillard JM, Plainchont B. Tutorial for the structure elucidation of small molecules by means of the LSD software. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2018; 56:458-468. [PMID: 28543725 DOI: 10.1002/mrc.4612] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 05/09/2017] [Accepted: 05/12/2017] [Indexed: 05/12/2023]
Abstract
Automatic structure elucidation of small molecules by means of the "logic for structure elucidation" (LSD) software is introduced in the context of the automatic exploitation of chemical shift correlation data and with minimal input from chemical shift values. The first step in solving a structural problem by means of LSD is the extraction of pertinent data from the 1D and 2D spectra. This operation requires the labeling of the resonances and of their correlations; its reliability highly depends on the quality of the spectra. The combination of COSY, HSQC, and HMBC spectra results in proximity relationships between nonhydrogen atoms that are associated in order to build the possible solutions of a problem. A simple molecule, camphor, serves as an example for the writing of an LSD input file and to show how solution structures are obtained. An input file for LSD must contain a nonambiguous description of each atom, or atom status, which includes the chemical element symbol, the hybridization state, the number of bound hydrogen atoms and the formal electric charge. In case of atom status ambiguity, the pyLSD program performs clarification by systematically generating the status of the atoms. PyLSD also proposes the use of the nmrshiftdb algorithm in order to rank the solutions of a problem according to the quality of the fit between the experimental carbon-13 chemical shifts, and the ones predicted from the proposed structures. To conclude, some hints toward future uses and developments of computer-assisted structure elucidation by LSD are proposed.
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16
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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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17
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Hallwass F, Teles RR, Hellemann E, Griesinger C, Gil RR, Navarro-Vázquez A. Measurement of residual chemical shift anisotropies in compressed polymethylmethacrylate gels. Automatic compensation of gel isotropic shift contribution. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2018; 56:321-328. [PMID: 29327368 DOI: 10.1002/mrc.4711] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Revised: 12/29/2017] [Accepted: 12/31/2017] [Indexed: 05/28/2023]
Abstract
Mechanical compression of polymer gels provides a simple way for the measurement of residual chemical shift anisotropies, which then can be employed, on its own, or in combination with residual dipolar couplings, for structural elucidation purposes. Residual chemical shift anisotropies measured using compression devices needed a posteriori correction to account for the increase of the polymer to solvent ratio inside the swollen gel. This correction has been cast before in terms of a single-free parameter which, as shown here, can be simultaneously optimized along with the components of the alignment tensor while still retaining discriminating power of the different relative configurations as illustrated in the stereochemical analysis of α-santonin and 10-epi-8-deoxycumambrin B.
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Affiliation(s)
- Fernando Hallwass
- Departamento de Química Fundamental, Universidade Federal de Pernambuco, Avenida Professor Moraes Rego, 1235, Cidade Universitária, 50670-901, Recife, Pernambuco, Brazil
- Department of NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, Fassberg 11, Göttingen, 37077, Germany
| | - Rubens R Teles
- Departamento de Química Fundamental, Universidade Federal de Pernambuco, Avenida Professor Moraes Rego, 1235, Cidade Universitária, 50670-901, Recife, Pernambuco, Brazil
- Instituto Federal da Paraíba, Campus Princesa Isabel, Rodovia PB 426, s/no, Princesa Isabel, CEP 58755-000, Paraíba, Brazil
| | - Erich Hellemann
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Ave, Pittsburgh, PA, 15213, USA
| | - Christian Griesinger
- Department of NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, Fassberg 11, Göttingen, 37077, Germany
| | - Roberto R Gil
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Ave, Pittsburgh, PA, 15213, USA
| | - Armando Navarro-Vázquez
- Departamento de Química Fundamental, Universidade Federal de Pernambuco, Avenida Professor Moraes Rego, 1235, Cidade Universitária, 50670-901, Recife, Pernambuco, Brazil
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18
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Parella T. Current developments in homonuclear and heteronuclear J-resolved NMR experiments. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2018; 56:230-250. [PMID: 29314247 DOI: 10.1002/mrc.4706] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 12/12/2017] [Accepted: 12/12/2017] [Indexed: 06/07/2023]
Abstract
Two-dimensional J-resolved (Jres) NMR experiments offer a simple, user-friendly spectral representation where the information of coupling constants and chemical shifts are separated into two orthogonal frequency axis. Since its initial proposal 40 years ago, Jres has been the focus of considerable interest both in improving the basic pulse sequence and in its successful application to a wide range of studies. Here, the latest developments in the design of novel Jres pulse schemes are reviewed, mainly focusing on obtaining pure absorption lineshapes, minimizing strong coupling artifacts, and also optimizing sensitivity and experimental measurements. A discussion of several Jres versions for the accurate measurement of a different number of homonuclear (JHH ) and heteronuclear (JCH ) coupling constants is presented, accompanied by some illustrative examples.
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Affiliation(s)
- Teodor Parella
- Servei de Ressonància Magnètica Nuclear, Universitat Autònoma de Barcelona, E-08193 Bellaterra, Barcelona, Catalonia, Spain
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19
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Sarotti AM. Structural revision of two unusual rhamnofolane diterpenes, curcusones I and J, by means of DFT calculations of NMR shifts and coupling constants. Org Biomol Chem 2018; 16:944-950. [DOI: 10.1039/c7ob02916k] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The structures of two unusual rhamnofolane diterpenes, curcusones I and J, have been revised using quantum calculations of NMR shifts.
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Affiliation(s)
- Ariel M. Sarotti
- Instituto de Química Rosario (CONICET)
- Facultad de Ciencias Bioquímicas y Farmacéuticas
- Universidad Nacional de Rosario
- Rosario 2000
- Argentina
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20
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Souza AA, Gil RR, Parella T. Highly resolved HSQC experiments for the fast and accurate measurement of homonuclear and heteronuclear coupling constants. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2017; 282:54-61. [PMID: 28759743 DOI: 10.1016/j.jmr.2017.07.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Revised: 07/10/2017] [Accepted: 07/13/2017] [Indexed: 06/07/2023]
Abstract
A number of J-upscaled NMR experiments are currently available to measure coupling constants along the indirect F1 dimension of a 2D spectrum. A major drawback is the limited F1 digital resolution that requires long acquisition times in order to achieve reasonably accurate measures. Here is shown how high levels of F1 digital resolution in a multiple-purpose HSQC experiment can be easily achieved by implementing a general J/δ-scaling strategy. In particular, a set of new J-resolved HSQC experiments is presented for a faster and much more accurate J determination in small molecules. Several options and practical aspects are discussed and exemplified by measuring the magnitude and/or the sign of several homo- and heteronuclear coupling constants in one shot.
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Affiliation(s)
- Alexandre A Souza
- Servei de Ressonància Magnètica Nuclear, Universitat Autònoma de Barcelona, E-08193 Bellaterra (Barcelona), Catalonia, Spain; Departamento de Química, Universidade Federal do Piauí, 64049-550 Teresina, PI, Brazil
| | - Roberto R Gil
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Teodor Parella
- Servei de Ressonància Magnètica Nuclear, Universitat Autònoma de Barcelona, E-08193 Bellaterra (Barcelona), Catalonia, Spain.
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21
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Cornilescu G, Ramos Alvarenga RF, Wyche TP, Bugni TS, Gil RR, Cornilescu CC, Westler WM, Markley JL, Schwieters CD. Progressive Stereo Locking (PSL): A Residual Dipolar Coupling Based Force Field Method for Determining the Relative Configuration of Natural Products and Other Small Molecules. ACS Chem Biol 2017; 12:2157-2163. [PMID: 28617580 DOI: 10.1021/acschembio.7b00281] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Establishing the relative configuration of a bioactive natural product represents the most challenging part in determining its structure. Residual dipolar couplings (RDCs) are sensitive probes of the relative spatial orientation of internuclear vectors. We adapted a force field structure calculation methodology to allow free sampling of both R and S configurations of the stereocenters of interest. The algorithm uses a floating alignment tensor in a simulated annealing protocol to identify the conformations and configurations that best fit experimental RDC and distance restraints (from NOE and J-coupling data). A unique configuration (for rigid molecules) or a very small number of configurations (for less rigid molecules) of the structural models having the lowest chiral angle energies and reasonable magnitudes of the alignment tensor are provided as the best predictions of the unknown configuration. For highly flexible molecules, the progressive locking of their stereocenters into their statistically dominant R or S state dramatically reduces the number of possible relative configurations. The result is verified by checking that the same configuration is obtained by initiating the locking from different regions of the molecule. For all molecules tested having known configurations (with conformations ranging from mostly rigid to highly flexible), the method accurately determined the correct configuration.
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Affiliation(s)
| | - René F. Ramos Alvarenga
- Pharmaceutical
Sciences Division, School of Pharmacy, University of Wisconsin—Madison, Madison, Wisconsin 53705, United States
| | - Thomas P. Wyche
- Pharmaceutical
Sciences Division, School of Pharmacy, University of Wisconsin—Madison, Madison, Wisconsin 53705, United States
- Biological
Chemistry and Molecular Pharmacology Department, Harvard Medical School, Boston, Massachusetts 02115, United States
| | - Tim S. Bugni
- Pharmaceutical
Sciences Division, School of Pharmacy, University of Wisconsin—Madison, Madison, Wisconsin 53705, United States
| | - Roberto R. Gil
- Department
of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | | | | | | | - Charles D. Schwieters
- Center for
Information Technology, National Institutes of Health, Bethesda, Maryland 20892-5624, United States
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22
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Navarro-Vázquez A, Berdagué P, Lesot P. Integrated Computational Protocol for the Analysis of Quadrupolar Splittings from Natural-Abundance Deuterium NMR Spectra in (Chiral) Oriented Media. Chemphyschem 2017; 18:1252-1266. [DOI: 10.1002/cphc.201601423] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Indexed: 11/07/2022]
Affiliation(s)
- Armando Navarro-Vázquez
- Departamento de Química Fundamental; Universidade Federal de Pernambuco Cidade Universitária; CEP: 50 740-540 Recife PE Brazil
- Institute of Organic Chemistry and Institute for Biological Interfaces; Karlsruhe Institute of Technology (KIT); Fritz-Haber-Weg 6 76131 Karlsruhe German
| | - Philippe Berdagué
- RMN en Milieu Orienté; ICMMO; UMR CNRS 8182; Université Paris-Sud/Université Paris-Saclay; Bât. 410 91405 Orsay cedex France
| | - Philippe Lesot
- RMN en Milieu Orienté; ICMMO; UMR CNRS 8182; Université Paris-Sud/Université Paris-Saclay; Bât. 410 91405 Orsay cedex France
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23
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França JAA, Navarro-Vázquez A, Lei X, Sun H, Griesinger C, Hallwass F. Complete NMR assignment and conformational analysis of 17-α-ethinylestradiol by using RDCs obtained in grafted graphene oxide. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2017; 55:297-303. [PMID: 27637176 DOI: 10.1002/mrc.4526] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Revised: 09/08/2016] [Accepted: 09/13/2016] [Indexed: 06/06/2023]
Abstract
The 1 H and 13 C NMR spectra of 17-α-ethinylestradiol (EE2), a well-known contraceptive, including diastereotopic methylene groups, were fully assigned with the help of residual dipolar couplings (RDC) measured in the recently developed grafted graphene oxide orienting medium. RDC analysis, which included all 1 DCH couplings and the long-range 2 DCH1 H-C≡13 C coupling, also pointed to the presence of a minor conformation arising from pseudo-rotation of the steroid B ring. Saturation-transfer difference (STD) measurements revealed that the most likely interaction between EE2 and orienting medium occurred on the C and D ring. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- José A A França
- Instituto Federal de Alagoas, Campus Piranhas, Avenida Sergipe, s/n° Xingó, 57460-000, Piranhas, AL, Brazil
| | - Armando Navarro-Vázquez
- Departamento de Química Fundamental, Universidade Federal de Pernambuco, Avenida Professor Moraes Rego, 1235, Cidade Universitária, 50670-901, Recife, PE, Brazil
| | - Xinxiang Lei
- School of Pharmaceutical Sciences, South Central University for Nationalities, Wuhan, 430074, PR China
| | - Han Sun
- Leibniz-Institut für Molekulare Pharmakologie (FMP), Robert-Robert-Rössle-StraΒe 10, 13125, Berlin, Germany
| | - Christian Griesinger
- Department of NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, Fassberg 11, 37077, Göttingen, Germany
| | - Fernando Hallwass
- Departamento de Química Fundamental, Universidade Federal de Pernambuco, Avenida Professor Moraes Rego, 1235, Cidade Universitária, 50670-901, Recife, PE, Brazil
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24
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García ME, Woodruff SR, Hellemann E, Tsarevsky NV, Gil RR. Di(ethylene glycol) methyl ether methacrylate (DEGMEMA)-derived gels align small organic molecules in methanol. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2017; 55:206-209. [PMID: 26763068 DOI: 10.1002/mrc.4400] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2015] [Revised: 10/20/2015] [Accepted: 11/24/2015] [Indexed: 05/28/2023]
Abstract
Residual dipolar couplings (RDCs) constitute an important NMR parameter for structural elucidation in all areas of chemistry. In this study, di(ethylene glycol) methyl ether methacrylate (DEGMEMA)-based gels are introduced as alignment media for the measurement of RDCs of small organic molecules in polar solvents such as methanol. The low viscosity of methanol permits the execution of J-scaled BIRD HSQC experiments that yield very sharp lines in anisotropic conditions. The gels have excellent mechanical properties, and their compression and expansion in the swollen state can be reversed and performed multiple times. This process enables the easy loading and release of analytes. The excellent performance of these new aligning gels is demonstrated by analyzing the structure of the alkaloid retrorsine. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Manuela E García
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA, 15213, USA
- Department of Organic Chemistry, National University of Cordoba, Medina Allende y Haya de La Torre, Cordoba, 5000, Argentina
| | - Shannon R Woodruff
- Department of Chemistry, Southern Methodist University, Dallas, TX, USA
- Center for Drug Discovery, Design, and Delivery in Dedman College, Southern Methodist University, Dallas, TX, USA
| | - Erich Hellemann
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA, 15213, USA
| | - Nicolay V Tsarevsky
- Department of Chemistry, Southern Methodist University, Dallas, TX, USA
- Center for Drug Discovery, Design, and Delivery in Dedman College, Southern Methodist University, Dallas, TX, USA
| | - Roberto R Gil
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA, 15213, USA
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25
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Marcó N, Souza AA, Nolis P, Gil RR, Parella T. Perfect 1J CH-resolved HSQC: Efficient measurement of one-bond proton-carbon coupling constants along the indirect dimension. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2017; 276:37-42. [PMID: 28092787 DOI: 10.1016/j.jmr.2017.01.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Revised: 12/30/2016] [Accepted: 01/01/2017] [Indexed: 06/06/2023]
Abstract
A versatile 1JCH-resolved HSQC pulse scheme for the speedy, accurate and automated determination of one-bond proton-carbon coupling constants is reported. The implementation of a perfectBIRD element allows a straightforward measurement from the clean doublets obtained along the highly resolved F1 dimension, even for each individual 1JCHa and 1JCHb in diastereotopic HaCHb methylene groups. Real-time homodecoupling during acquisition and other alternatives to minimize accidental signal overlapping in overcrowded spectra are also discussed.
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Affiliation(s)
- N Marcó
- Servei de Ressonància Magnètica Nuclear, Universitat Autònoma de Barcelona, E-08193 Bellaterra (Barcelona), Catalonia, Spain
| | - A A Souza
- Servei de Ressonància Magnètica Nuclear, Universitat Autònoma de Barcelona, E-08193 Bellaterra (Barcelona), Catalonia, Spain; Departamento de Química, Universidade Federal do Piauí, 64049-550 Teresina, PI, Brazil
| | - P Nolis
- Servei de Ressonància Magnètica Nuclear, Universitat Autònoma de Barcelona, E-08193 Bellaterra (Barcelona), Catalonia, Spain
| | - R R Gil
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA, USA
| | - T Parella
- Servei de Ressonància Magnètica Nuclear, Universitat Autònoma de Barcelona, E-08193 Bellaterra (Barcelona), Catalonia, Spain.
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26
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Troche‐Pesqueira E, Anklin C, Gil RR, Navarro‐Vázquez A. Computer‐Assisted 3D Structure Elucidation of Natural Products using Residual Dipolar Couplings. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201612454] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Clemens Anklin
- Bruker BioSpin Corp. 15 Fortune Dr. Billerica MA 01821 USA
| | - Roberto R. Gil
- Department of Chemistry Carnegie Mellon University 4400 Fifth Ave Pittsburgh PA 15213 USA
| | - Armando Navarro‐Vázquez
- Departamento de Química Fundamental, CCEN Universidade Federal de Pernambuco Brazil
- Departamento de Química Orgánica Universidade de Vigo 36310 Vigo Spain
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27
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Troche‐Pesqueira E, Anklin C, Gil RR, Navarro‐Vázquez A. Computer‐Assisted 3D Structure Elucidation of Natural Products using Residual Dipolar Couplings. Angew Chem Int Ed Engl 2017; 56:3660-3664. [DOI: 10.1002/anie.201612454] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Indexed: 11/06/2022]
Affiliation(s)
| | - Clemens Anklin
- Bruker BioSpin Corp. 15 Fortune Dr. Billerica MA 01821 USA
| | - Roberto R. Gil
- Department of Chemistry Carnegie Mellon University 4400 Fifth Ave Pittsburgh PA 15213 USA
| | - Armando Navarro‐Vázquez
- Departamento de Química Fundamental, CCEN Universidade Federal de Pernambuco Brazil
- Departamento de Química Orgánica Universidade de Vigo 36310 Vigo Spain
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28
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Schmidts V. Perspectives in the application of residual dipolar couplings in the structure elucidation of weakly aligned small molecules. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2017; 55:54-60. [PMID: 27743456 DOI: 10.1002/mrc.4543] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Revised: 10/10/2016] [Accepted: 10/13/2016] [Indexed: 05/28/2023]
Abstract
This perspective article aims to review the general methodology in the application of residual dipolar couplings (RDCs) in the structure elucidation of small molecules and give the author's view on challenges for future applications. Recent improvements in the availability of alignment media, new pulse sequences for the measurement of couplings and improvements in the analysis software have garnered widespread interest in the technique. However, further generalization is needed in order to make RDC analysis into a truly "routine" method. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Volker Schmidts
- Clemens-Schöpf-Institut für Organische Chemie und Biochemie, Technische Universität Darmstadt, Darmstadt, Germany
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29
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Zanardi MM, Suárez AG, Sarotti AM. Determination of the Relative Configuration of Terminal and Spiroepoxides by Computational Methods. Advantages of the Inclusion of Unscaled Data. J Org Chem 2016; 82:1873-1879. [DOI: 10.1021/acs.joc.6b02129] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- María M. Zanardi
- Instituto
de Química Rosario (CONICET), Facultad de Ciencias Bioquímicas
y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, Rosario 2000, Argentina
- Facultad
de Química e Ingeniería del Rosario, Pontificia Universidad Católica Argentina, Av Pellegrini 3314, Rosario 2000, Argentina
| | - Alejandra G. Suárez
- Instituto
de Química Rosario (CONICET), Facultad de Ciencias Bioquímicas
y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, Rosario 2000, Argentina
| | - 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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30
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Nath N, Schmidt M, Gil RR, Williamson RT, Martin GE, Navarro-Vázquez A, Griesinger C, Liu Y. Determination of Relative Configuration from Residual Chemical Shift Anisotropy. J Am Chem Soc 2016; 138:9548-56. [DOI: 10.1021/jacs.6b04082] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Nilamoni Nath
- Department
of NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Manuel Schmidt
- Department
of NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Roberto R. Gil
- Department
of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - R. Thomas Williamson
- Process Research and Development, NMR Structure Elucidation Group, Merck & Co., Inc., 126 E Lincoln Avenue, Rahway, New Jersey 07065, United States
| | - Gary E. Martin
- Process Research and Development, NMR Structure Elucidation Group, Merck & Co., Inc., 126 E Lincoln Avenue, Rahway, New Jersey 07065, United States
| | - Armando Navarro-Vázquez
- Departamento
de Química Fundamental, Universidade Federal de Pernambuco, Cidade Universitária, Recife, PE 50740-560, Brazil
- Institute
of Organic Chemistry and Institute for Biological Interfaces Karlsruhe, Institute of Technology (KIT), Fritz-Haber-Weg 6, 76131 Karlsruhe, Germany
| | - Christian Griesinger
- Department
of NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Yizhou Liu
- Process Research and Development, NMR Structure Elucidation Group, Merck & Co., Inc., 126 E Lincoln Avenue, Rahway, New Jersey 07065, United States
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31
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Nath N, d'Auvergne EJ, Griesinger C. Long-Range Residual Dipolar Couplings: A Tool for Determining the Configuration of Small Molecules. Angew Chem Int Ed Engl 2015; 54:12706-10. [PMID: 26359945 DOI: 10.1002/anie.201504432] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Revised: 07/14/2015] [Indexed: 11/07/2022]
Abstract
Together with NOE and J coupling, one-bond residual dipolar coupling (RDC), which reports on the three-dimensional orientation of an internuclear vector in the molecular frame, plays an important role in the conformation and configuration analysis of small molecules in solution by NMR spectroscopy. When the molecule has few C-H bonds, or too many bonds are in parallel, the available RDCs may not be sufficient to obtain the alignment tensor used for structure elucidation. Long-range RDCs that connect nuclei over multiple bonds are normally not parallel to the single bonds and therefore complement one-bond RDCs. Herein we present a method for extracting the long-range RDC of a chosen proton or group of protons to all remotely connected carbon atoms, including non-protonated carbon atoms. Alignment tensors fitted directly to the total long-range couplings (T=J+D) enabled straightforward analysis of both the long-range and one-bond RDCs for strychnine.
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Affiliation(s)
- Nilamoni Nath
- Department of NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen (Germany)
| | - Edward J d'Auvergne
- Department of NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen (Germany)
| | - Christian Griesinger
- Department of NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen (Germany).
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32
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Nath N, d'Auvergne EJ, Griesinger C. Long-Range Residual Dipolar Couplings: A Tool for Determining the Configuration of Small Molecules. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201504432] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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33
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Fredersdorf M, Göstl R, Kolmer A, Schmidts V, Monecke P, Hecht S, Thiele CM. Exploring the Conformational Space of Bridge-Substituted Dithienylcyclopentenes. Chemistry 2015; 21:14545-54. [DOI: 10.1002/chem.201501842] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Indexed: 11/08/2022]
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34
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Riveira MJ, Trigo-Mouriño P, Troche-Pesqueira E, Martin GE, Navarro-Vázquez A, Mischne MP, Gil RR. Self-Sensitized Photooxygenation of 2H-Pyrans: Characterization of Unexpected Products Assisted by Computed Structural Elucidation and Residual Dipolar Couplings. J Org Chem 2015; 80:7396-402. [DOI: 10.1021/acs.joc.5b00817] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Martín J. Riveira
- Instituto
de Química Rosario, Facultad de Ciencias Bioquímicas
y Farmacéuticas, Universidad Nacional de Rosario-CONICET, Suipacha
531, S2002LRK Rosario, Argentina
| | - Pablo Trigo-Mouriño
- Department
of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Eduardo Troche-Pesqueira
- Department
of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
- Departamento
de Química Orgánica, Edificio de Ciencias Experimentais, Universidade de Vigo,
Campus Universitario, 36310 Vigo, Spain
| | - Gary E. Martin
- NMR Structure Elucidation, Process & Analytical Chemistry, Merck Research Laboratories, Rahway, New Jersey 07065, United States
| | - Armando Navarro-Vázquez
- Departamento
de Química Fundamental, Universidade Federal de Pernambuco, Cidade Universitária,
CEP 50.740-540 Recife, Pernambuco, Brazil
| | - Mirta P. Mischne
- Instituto
de Química Rosario, Facultad de Ciencias Bioquímicas
y Farmacéuticas, Universidad Nacional de Rosario-CONICET, Suipacha
531, S2002LRK Rosario, Argentina
| | - Roberto R. Gil
- Department
of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
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35
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Lancefield CS, Slawin AMZ, Westwood NJ, Lebl T. The use of residual dipolar coupling for conformational analysis of structurally related natural products. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2015; 53:467-75. [PMID: 25854705 DOI: 10.1002/mrc.4213] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Revised: 12/23/2014] [Accepted: 12/28/2014] [Indexed: 05/28/2023]
Abstract
Determining the conformational preferences of molecules in solution remains a considerable challenge. Recently, the use of residual dipolar coupling (RDC) analysis has emerged as a key method to address this. Whilst to date the majority of the applications have focused on biomolecules including proteins and DNA, the use of RDCs for studying small molecules is gaining popularity. Having said that, the method continues to develop, and here, we describe an early case study of the quantification of conformer populations in small molecules using RDC analysis. Having been inspired to study conformational preferences by unexpected differences in the NMR spectra and the reactivity of related natural products, we showed that the use of more established techniques was unsatisfactory in explaining the experimental observations. The use of RDCs provided an improved understanding that, following use of methods to quantify conformer populations using RDCs, culminated in a rationalisation of the contrasting diastereoselectivities observed in a ketone reduction reaction.
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Affiliation(s)
- Christopher S Lancefield
- School of Chemistry and Biomedical Sciences Research Complex, University of St Andrews and EaStCHEM, North Haugh, St Andrews, KY16 9ST, UK
| | - Alexandra M Z Slawin
- School of Chemistry and Biomedical Sciences Research Complex, University of St Andrews and EaStCHEM, North Haugh, St Andrews, KY16 9ST, UK
| | - Nicholas J Westwood
- School of Chemistry and Biomedical Sciences Research Complex, University of St Andrews and EaStCHEM, North Haugh, St Andrews, KY16 9ST, UK
| | - Tomas Lebl
- School of Chemistry and Biomedical Sciences Research Complex, University of St Andrews and EaStCHEM, North Haugh, St Andrews, KY16 9ST, UK
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36
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Juárez-González F, Suárez-Ortiz GA, Fragoso-Serrano M, Cerda-García-Rojas CM, Pereda-Miranda R. DFT 1H-1H coupling constants in the conformational analysis and stereoisomeric differentiation of 6-heptenyl-2H-pyran-2-ones: configurational reassignment of synargentolide A. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2015; 53:203-212. [PMID: 25353378 DOI: 10.1002/mrc.4178] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Revised: 10/05/2014] [Accepted: 10/08/2014] [Indexed: 06/04/2023]
Abstract
Density functional theory (DFT) (1) H-(1) H NMR coupling constant calculations, including solvation parameters with the polarizable continuum model B3LYP/DGDZVP basis set together with the experimental values measured by spectral simulation, were used to predict the configuration of hydroxylated 6-heptenyl-5,6-dihydro-2H-pyran-2-ones 1, 2, 4, and 7, allowing epimer differentiation. Modeling of these flexible compounds requires the inclusion of solvation models that account for stabilizing interactions derived from intramolecular and intermolecular hydrogen bonds, in contrast with peracetylated derivatives (3, 5, and 6) in which the solvation consideration can be omitted. Using this DFT NMR integrated approach as well as spectral simulation, the configurational reassignment of synargentolide A (8) was accomplished by calculations in the gas phase among four possible diastereoisomers (8-11). Calculated (3) JH,H values established its configuration as 6R-[4'S,5'S,6'S-(triacetyloxy)-2E-heptenyl]-5,6-dihydro-2H-pyran-2-one (8), in contrast with the incorrect 6R,4'R,5'R,6'R-diastereoisomer previously proposed by synthesis (12). Application of this approach increases the probability for successful enantiospecific total syntheses of flexible compounds with multiple chiral centers.
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Affiliation(s)
- Francisco Juárez-González
- Departamento de Farmacia, Facultad de Química, Universidad Nacional Autónoma de México, Ciudad Universitaria, Mexico City, 04510, DF, Mexico
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37
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Marcó N, Fredi A, Parella T. Ultra high-resolution HSQC: application to the efficient and accurate measurement of heteronuclear coupling constants. Chem Commun (Camb) 2015; 51:3262-5. [DOI: 10.1039/c4cc10279g] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A rapid acquisition strategy in terms of enhanced resolution per time unit for the simple and efficient determination of multiple coupling constants is proposed. The use of 13C spectral aliasing combined with pure shift NMR techniques allows accurate measurements of the magnitude and the sign from ultra high resolved 2D cross-peaks.
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Affiliation(s)
- Núria Marcó
- Servei de Ressonància Magnètica Nuclear
- Universitat Autònoma de Barcelona
- E-08193 Bellaterra
- Spain
| | - André Fredi
- Servei de Ressonància Magnètica Nuclear
- Universitat Autònoma de Barcelona
- E-08193 Bellaterra
- Spain
| | - Teodor Parella
- Servei de Ressonància Magnètica Nuclear
- Universitat Autònoma de Barcelona
- E-08193 Bellaterra
- Spain
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38
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RES-TOCSY: A facile approach for accurate determination of magnitudes, and relative signs of nJHF. Chem Phys Lett 2014. [DOI: 10.1016/j.cplett.2014.04.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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39
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Troche-Pesqueira E, Cid MM, Navarro-Vázquez A. Disodium cromoglycate: exploiting its properties as a NMR weak-aligning medium for small organic molecules. Org Biomol Chem 2014; 12:1957-65. [DOI: 10.1039/c3ob42338g] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Disodium cromoglycate (cromolyn) is an easy-to-prepare water-compatible NMR weak aligning medium for small molecules.
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Affiliation(s)
| | - María-Magdalena Cid
- Departamento de Quıímica Orgánica
- Edificio de Ciencias Experimentais
- Vigo, 36310 Spain
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40
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Kakita VMR, Rachineni K, Bharatam J. Unambiguous determination of conformation and relative configuration of a multiple stereo-centre molecule Rifamycin-S by using scaled residual dipolar couplings: A case study. J Mol Struct 2013. [DOI: 10.1016/j.molstruc.2013.08.061] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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41
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Trigo-Mouriño P, de la Fuente MC, Gil RR, Sánchez-Pedregal VM, Navarro-Vázquez A. Conformational Analysis of the Anti-obesity Drug Lorcaserin in Water: How To Take Advantage of Long-Range Residual Dipolar Couplings. Chemistry 2013; 19:14989-97. [DOI: 10.1002/chem.201202509] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Revised: 06/28/2013] [Indexed: 11/07/2022]
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42
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Dama M, Berger S. Ionic liquid crystals as alignment medium to measure residual dipolar couplings for carbohydrates. Carbohydr Res 2013; 377:44-7. [PMID: 23806381 DOI: 10.1016/j.carres.2013.05.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2013] [Revised: 05/23/2013] [Accepted: 05/30/2013] [Indexed: 11/19/2022]
Abstract
Ionic liquids consisting of N-dodecyl-N-methyl pyrrolidinium bromide [C12MPB] in a mixture with D2O, decanol, and DMSO were for the first time found to give anisotropic molecular alignment in magnetic fields and are useful to measure residual dipolar couplings (RDCs) from polar analytes, for example, glucose. The system shows less quadrupolar splitting of the deuterated solvent signal compared with other liquid crystal systems and hence less undesired line broadening.
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Affiliation(s)
- Murali Dama
- Institute of Analytical Chemistry, University Leipzig, Leipzig, Germany
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43
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Parella T, Espinosa JF. Long-range proton-carbon coupling constants: NMR methods and applications. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2013; 73:17-55. [PMID: 23962883 DOI: 10.1016/j.pnmrs.2013.07.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Revised: 07/03/2013] [Accepted: 07/03/2013] [Indexed: 06/02/2023]
Abstract
A general review of novel NMR methods to measure heteronuclear long-range proton-carbon coupling constants ((n)JCH; n>1) in small molecules is made. NMR experiments are classified in terms of NMR pulse scheme and cross-peak nature. A discussion about simplicity, general applicability and accuracy for each particular NMR experiment is presented and exemplified. Important aspects such as the sign determination and measurement of very small coupling values involving protonated and non-protonated carbons as well as the complementarity between different experiments are also discussed. Finally, a compilation of applications in structural and conformational analysis of different types of molecules since 2000 is surveyed.
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Affiliation(s)
- Teodor Parella
- Servei de Ressonància Magnètica Nuclear, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain.
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44
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Saurí J, Parella T. Simultaneous measurement of J(HH) and two different (n)J(CH) coupling constants from a single multiply edited 2D cross-peak. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2013; 51:397-402. [PMID: 23649408 DOI: 10.1002/mrc.3960] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Revised: 04/02/2013] [Accepted: 04/03/2013] [Indexed: 06/02/2023]
Abstract
Three different J-editing methods (IPAP, E.COSY and J-resolved) are implemented in a single NMR experiment to provide spin-state-edited 2D cross-peaks from which a simultaneous measurement of different homonuclear and heteronuclear coupling constants can be performed. A new J-selHSQMBC-IPAP experiment is proposed for the independent measurement of two different (n)J(CH) coupling constants along the F2 and F1 dimensions of the same 2D cross-peak. In addition, the E.COSY pattern provides additional information about the magnitude and relative sign between J(HH) and (n)J(CH) coupling constants.
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Affiliation(s)
- Josep Saurí
- Servei de Ressonància Magnètica Nuclear, Universitat Autònoma de Barcelona, 08193, Bellaterra, Catalonia, Spain
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45
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Schmidts V, Fredersdorf M, Lübken T, Porzel A, Arnold N, Wessjohann L, Thiele CM. RDC-based determination of the relative configuration of the fungicidal cyclopentenone 4,6-diacetylhygrophorone A12. JOURNAL OF NATURAL PRODUCTS 2013; 76:839-844. [PMID: 23659349 DOI: 10.1021/np300728b] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The hygrophorones, a class of cyclopentenones isolated from fruiting bodies of the genus Hygrophorus (basidiomycetes), show promising antifungal activity. While the constitution of 4,6-diacetylhygrophorone A(12) (3) and the relative configuration of the stereogenic centers in the cyclopentenone ring were elucidated using standard NMR and MS techniques, the relative configuration of the exocyclic stereogenic center could not be assigned. By introducing a sample of 3 into an alignment medium and measuring anisotropic NMR parameters, namely, residual dipolar couplings, we were able to unambiguously determine the relative configuration of all three stereogenic centers in 4,6-diacetylhygrophorone A(12) simultaneously by fitting several structure proposals to the experimental data.
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Affiliation(s)
- Volker Schmidts
- Clemens Schöpf Institute for Organic Chemistry and Biochemistry, Technische Universität Darmstadt, Petersenstraße 22, Darmstadt, Germany
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46
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Dama M, Berger S. Study of an Organogelator by Diffusion-Ordered NMR Spectroscopy. J Phys Chem B 2013; 117:5788-91. [DOI: 10.1021/jp401963t] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Murali Dama
- Institute of Analytical Chemistry, University of Leipzig, Johannisallee 29, 04103 Leipzig,
Germany
| | - Stefan Berger
- Institute of Analytical Chemistry, University of Leipzig, Johannisallee 29, 04103 Leipzig,
Germany
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47
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Canales A, Jiménez-Barbero J, Martín-Pastor M. Review: Use of residual dipolar couplings to determine the structure of carbohydrates. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2012; 50 Suppl 1:S80-S85. [PMID: 23280664 DOI: 10.1002/mrc.3888] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Revised: 09/08/2012] [Accepted: 09/20/2012] [Indexed: 05/28/2023]
Abstract
Solution nuclear magnetic resonance spectroscopy is especially useful in the carbohydrate field. The measurement of residual dipolar couplings provides long-range structural information, a valuable complement for the structural study of carbohydrates either in its free form or in the bound state to proteins. They permit to deduce the geometry and the flexibility of the glycosidic linkages, which have a major influence on the conformation of carbohydrates and their overall shape. This article reviews the current application of the residual dipolar couplings methodology to carbohydrates.
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Affiliation(s)
- A Canales
- Department Organic Chemistry, Universidad Complutense de Madrid, Madrid, Spain
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48
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Schmidt M, Sun H, Leonov A, Griesinger C, Reinscheid UM. Chiral discrimination of amines by anisotropic NMR parameters using chiral polyacrylamide-based gels. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2012; 50 Suppl 1:S38-S44. [PMID: 23280659 DOI: 10.1002/mrc.3886] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2012] [Revised: 09/01/2012] [Accepted: 09/14/2012] [Indexed: 05/28/2023]
Abstract
A new chiral alignment medium for dimethyl sulfoxide, methanol, and water as solvents was developed. Because both enantiomers of the gel are available, it is possible to enantiodiscriminate natural products such as strychnine HCl that naturally occurs as single enantiomer. With the two methods of achieving anisotropy, namely stretching and confinement, the degree of alignment can be adjusted, and the director changed from horizontal to vertical. This increases the applicability. Three compounds were enantiodiscriminated on the basis of residual dipolar coupling data: mefloquine HCl, strychnine HCl, and menthylamine HCl.
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Affiliation(s)
- Manuel Schmidt
- Max Planck Institute for Biophysical Chemistry, NMR II, 37077 Göttingen, Germany
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49
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Snider JD, Troche-Pesqueira E, Woodruff SR, Gayathri C, Tsarevsky NV, Gil RR. New strategy for RDC-assisted diastereotopic proton assignment using a combination of J-scaled BIRD HSQC and J-scaled BIRD HMQC/HSQC. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2012; 50 Suppl 1:S86-S91. [PMID: 23280665 DOI: 10.1002/mrc.3895] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2012] [Revised: 09/28/2012] [Accepted: 10/03/2012] [Indexed: 06/01/2023]
Abstract
A new strategy to assign diastereotopic protons was developed on the basis of residual dipolar couplings (RDCs) collected in compressed poly(methyl methacrylate) (PMMA) gels. A combination of 2D J-scaled BIRD HSQC and J-scaled BIRD HMQC/HSQC NMR experiments was used to collect the RDC data. In the proposed strategy, the first experiment is used to measure (1)D(CH) for methine groups, the sum of (1)D(CHa) + (1)D(CHb) for methylene groups and the average (1)D(CH3) value for methyl groups. In turn, the small molecule alignment tensor is calculated using these D values without the a priori assignment of CH(2) diastereotopic protons. The D values of each individual CH bond (CHa and CHb) of each methylene group in the molecule are then predicted using the calculated alignment tensor and these values compared with the results from the HMQC/HSQC experiment, leading to their unambiguous assignment. This strategy is demonstrated with the alkaloid strychnine that contains five methylene groups with diastereotopic protons, and our results fully agree with the previously reported assignment using combinations of permutated assignments.
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Affiliation(s)
- Jonathan D Snider
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA, USA
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50
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Saurí J, Nolis P, Castañar L, Virgili A, Parella T. P.E.HSQMBC: simultaneous measurement of proton-proton and proton-carbon coupling constants. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2012; 224:101-106. [PMID: 23069350 DOI: 10.1016/j.jmr.2012.09.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Revised: 09/10/2012] [Accepted: 09/17/2012] [Indexed: 06/01/2023]
Abstract
A long-range optimized P.E.HSQC experiment, named P.E.HSQMBC, is proposed for the simultaneous measurement of a complete set of homonuclear and heteronuclear coupling constants from a single 2D cross-peak. The sign and the magnitude of proton-proton coupling constants are measured along the direct dimension from the relative E.COSY-type multiplet pattern displacement due to the passive one-bond coupling constant splitting generated in the indirect dimension. On the other hand, long-range proton-carbon coupling constants are independently determined in the detected dimension from a traditional fitting analysis of antiphase multiplet patterns or, more conveniently, from the IPAP multiplet displacement obtained from extended HSQMBC experiments.
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Affiliation(s)
- Josep Saurí
- Servei de Ressonància Magnètica Nuclear, Universitat Autònoma de Barcelona, E-08193 Bellaterra, Barcelona, Spain
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