1
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Elsing D, Luy B, Kozlowska M. Enantiomer Differentiation by Interaction-Specific Prediction of Residual Dipolar Couplings in Spherical-like Molecules. J Chem Theory Comput 2024. [PMID: 39099221 DOI: 10.1021/acs.jctc.4c00441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/06/2024]
Abstract
Residual Dipolar Couplings (RDCs) are averaged dipolar couplings between nuclear spins of atoms in a molecule that can be measured by nuclear magnetic resonance (NMR) spectroscopy upon partial alignment by a chiral alignment medium. The estimation of differences in alignment of enantiomers may, in principle, enable the determination of absolute configuration. Here, we use molecular dynamics (MD) simulations to mimic the alignment of chiral molecules (i.e., isopinocampheol, quinuclidin-3-ol, borneol, and camphor) to the chiral poly-γ-benzyl-L-glutamate (PBLG) polymer to predict RDCs in silico and compare calculated and experimentally measured residual dipolar couplings for the four enantiomeric pairs. The aim is to validate the computational scheme for the prediction of RDCs in chiral molecules and understand the interaction leading to the alignment in more detail. We determine the indispensable importance of hydrogen bonds between a chiral molecule and the alignment medium on the overall quality of the simulated alignment and interaction poses toward high agreement with experiments. A good correlation with experimental data is found for camphor and isopinocampheol, while the correlation for quinuclidin-3-ol and borneol is lower. We attribute this observation to the high difficulty of the RDC prediction for rather almost spherical molecules. The study reveals that the prediction of alignment with small enantiomeric differences is possible with an MD-based approach; however, extended simulation times (e.g., 50-100 μs) are required to sufficiently reduce the statistical uncertainty. This may be further used for the determination of the relative, as well as absolute, configuration of chiral molecules.
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Affiliation(s)
- David Elsing
- Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), Kaiserstr. 12, 76131 Karlsruhe, Germany
| | - Burkhard Luy
- Institute for Biological Interfaces 4, Karlsruhe Institute of Technology (KIT), Kaiserstr. 12, 76131 Karlsruhe, Germany
- Institute of Organic Chemistry, Karlsruhe Institute of Technology (KIT), Kaiserstr. 12, 76131 Karlsruhe, Germany
| | - Mariana Kozlowska
- Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), Kaiserstr. 12, 76131 Karlsruhe, Germany
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2
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Silva Elipe MV, Ndukwe IE, Murray JI. Cryogen-free 400-MHz nuclear magnetic resonance spectrometer as a versatile tool for pharmaceutical process analytical technology. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2024; 62:512-534. [PMID: 38369696 DOI: 10.1002/mrc.5434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 01/15/2024] [Accepted: 01/16/2024] [Indexed: 02/20/2024]
Abstract
The discovery of new ceramic materials containing Ba-La-Cu oxides in 1986 that exhibited superconducting properties at high temperatures in the range of 35 K or higher, recognized with the Nobel Prize in Physics in 1987, opened a new world of opportunities for nuclear magnetic resonance (NMRs) and magnetic resonance imaging (MRIs) to move away from liquid cryogens. This discovery expands the application of high temperature superconducting (HTS) materials to fields beyond the chemical and medical industries, including electrical power grids, energy, and aerospace. The prototype 400-MHz cryofree HTS NMR spectrometer installed at Amgen's chemistry laboratory has been vital for a variety of applications such as structure analysis, reaction monitoring, and CASE-3D studies with RDCs. The spectrometer has been integrated with Amgen's chemistry and analytical workflows, providing pipeline project support in tandem with other Kinetic Analysis Platform technologies. The 400-MHz cryofree HTS NMR spectrometer, as the name implies, does not require liquid cryogens refills and has smaller footprint that facilitates installation into a chemistry laboratory fume hood, sharing the hood with a process chemistry reactor. Our evaluation of its performance for structural analysis with CASE-3D protocol and for reaction monitoring of Amgen's pipeline chemistry was successful. We envision that the HTS magnets would become part of the standard NMR and MRI spectrometers in the future. We believe that while the technology is being developed, there is room for all magnet options, including HTS, low temperature superconducting (LTS) magnets, and low field benchtop NMRs with permanent magnets, where utilization will be dependent on application type and costs.
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Affiliation(s)
| | - Ikenna Edward Ndukwe
- Department of Attribute Sciences, Process Development, Amgen Inc., Thousand Oaks, California, USA
| | - James I Murray
- Pivotal and Commercial Drug Substance Technologies, Process Development, Amgen Inc., Thousand Oaks, California, USA
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3
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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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4
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Yu G, Chen Y, Peng Y, Wang G, Zhu M, Zhao X, Yang M, Zhang X, Liu M, He L. Temperature-Controllable Liquid Crystalline Medium for Stereochemical Elucidation of Organic Compounds via Residual Chemical Shift Anisotropies. Anal Chem 2024. [PMID: 38335322 DOI: 10.1021/acs.analchem.3c04477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2024]
Abstract
The configuration elucidation of organic molecules continues to pose significant challenges in studies involving stereochemistry. Nuclear magnetic resonance (NMR) techniques are powerful for obtaining such structural information. Anisotropic NMR techniques, such as measurement of residual dipolar couplings (RDCs) and residual chemical shift anisotropies (RCSAs), complementing isotropic NMR parameters, provide relative configuration information. RCSAs provide valuable structural information, especially for nonprotonated carbons, yet have been severely underutilized due to the lack of an easily operational alignment medium capable of rapid transition from anisotropic to isotropic environments, especially in aqueous conditions. In this study, an oligopeptide-based alignment media (FK)4 is presented for RCSA measurements. Temperature variation manipulates the assembly of (FK)4, yielding tunable anisotropic and isotropic phases without the requirement of any special devices or time-consuming correction procedures during data analysis. Decent observed ΔΔRCSA values from sp3 carbons benefit the utilization of RCSA measurements in the structural elucidation of organic molecules highly composed with sp3 carbons. Moreover, the (FK)4 alignment medium is applicable for both RDC and RCSA measurements in one sample, further advancing the configuration analysis of molecules of interest.
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Affiliation(s)
- Gangjin Yu
- State Key Laboratory of Magnetic Resonance and Atomic Molecular Physics, National Center for Magnetic Resonance in Wuhan, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Hubei 430071, China
| | - Yihao Chen
- State Key Laboratory of Magnetic Resonance and Atomic Molecular Physics, National Center for Magnetic Resonance in Wuhan, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Hubei 430071, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yun Peng
- State Key Laboratory of Magnetic Resonance and Atomic Molecular Physics, National Center for Magnetic Resonance in Wuhan, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Hubei 430071, China
| | - Guan Wang
- State Key Laboratory of Magnetic Resonance and Atomic Molecular Physics, National Center for Magnetic Resonance in Wuhan, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Hubei 430071, China
| | - Mingjun Zhu
- State Key Laboratory of Magnetic Resonance and Atomic Molecular Physics, National Center for Magnetic Resonance in Wuhan, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Hubei 430071, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaoling Zhao
- Department of Reproductive Medicine General Hospital of Central Theater Command of the People's Liberation Army, Wuhan, Hubei 430061, China
| | - Minghui Yang
- State Key Laboratory of Magnetic Resonance and Atomic Molecular Physics, National Center for Magnetic Resonance in Wuhan, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Hubei 430071, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xu Zhang
- State Key Laboratory of Magnetic Resonance and Atomic Molecular Physics, National Center for Magnetic Resonance in Wuhan, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Hubei 430071, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Maili Liu
- State Key Laboratory of Magnetic Resonance and Atomic Molecular Physics, National Center for Magnetic Resonance in Wuhan, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Hubei 430071, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Optics Valley Laboratory, Wuhan,Hubei 430074, China
| | - Lichun He
- State Key Laboratory of Magnetic Resonance and Atomic Molecular Physics, National Center for Magnetic Resonance in Wuhan, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Hubei 430071, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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5
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Li GW, Wang XJ, Shi SH, Liu LT, Li JQ, Sun H, Wu ZQ, Lei X. Polyarylisocyanides Derived from an Alkyne-Pd(II) Catalyst as Robust Alignment Media with Excellent Enantiodiscimination. Anal Chem 2023; 95:18850-18858. [PMID: 38091507 DOI: 10.1021/acs.analchem.3c04240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2023]
Abstract
The development of chiral alignment media for measuring anisotropic NMR parameters provides an opportunity to determine the absolute configuration of chiral molecules without the need for derivatization. However, chiral alignment media with a high and robust enantiodiscriminating property for a wide range of chiral molecules are still scarce. In this study, we synthesized cholesterol-end-functionalized helical polyisocyanides from a chiral monomer using a cholesterol-based alkyne-Pd(II) initiator. These stereoregular polyisocyanides form stable and weak anisotropic lyotropic liquid crystals (LLCs) in dichloromethane systems, exhibiting highly optical activities in both single left- and right-handed helices. The preparation process of the media was straightforward, and the aligning property of the LLCs could be controlled by adjusting the concentration and temperature. Using the chiral polyisocyanides, we extracted the residual dipolar coupling for an enantiomeric pair of isopinocampheol (IPC), as well as a number of pharmaceutical molecules, demonstrating excellent enantiodiscriminating properties for a broad range of chiral compounds.
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Affiliation(s)
- Gao-Wei Li
- College of Chemistry and Chemical Engineering, Henan Engineering Research Center for Green Synthesis of Pharmaceuticals, Shangqiu Normal University, Shangqiu 476000, China
| | - Xiao-Juan Wang
- College of Chemistry and Chemical Engineering, Henan Engineering Research Center for Green Synthesis of Pharmaceuticals, Shangqiu Normal University, Shangqiu 476000, China
| | - Shuai-Hua Shi
- College of Chemistry and Chemical Engineering, Henan Engineering Research Center for Green Synthesis of Pharmaceuticals, Shangqiu Normal University, Shangqiu 476000, China
| | - Lan-Tao Liu
- College of Chemistry and Chemical Engineering, Henan Engineering Research Center for Green Synthesis of Pharmaceuticals, Shangqiu Normal University, Shangqiu 476000, China
| | - Jia-Qian Li
- School of Pharmaceutical Sciences, South-Central Minzu University, Wuhan 430074, China
| | - Han Sun
- Research Unit of Structural Chemistry & Computational Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin 13125, Germany
- Institute of Chemistry, Technical University of Berlin, Berlin 10623, Germany
| | - Zong-Quan Wu
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, China
| | - Xinxiang Lei
- State Key Laboratory of Applied Organic Chemistry, Lanzhou Magnetic Resonance Center, College of Chemistry and Chemi-cal Engineering, Lanzhou University, Lanzhou 730000, China
- School of Pharmaceutical Sciences, South-Central Minzu University, Wuhan 430074, China
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6
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Franco BA, Luciano ER, Sarotti AM, Zanardi MM. DP4+App: Finding the Best Balance between Computational Cost and Predictive Capacity in the Structure Elucidation Process by DP4+. Factors Analysis and Automation. JOURNAL OF NATURAL PRODUCTS 2023; 86:2360-2367. [PMID: 37721602 DOI: 10.1021/acs.jnatprod.3c00566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/19/2023]
Abstract
DP4+ is one of the most popular methods for the structure elucidation of natural products using NMR calculations. While the method is simple and easy to implement, it requires a series of procedures that can be tedious, coupled with the fact that its computational demand can be high in certain cases. In this work, we made a substantial improvement to these limitations. First, we deeply explored the effect of molecular mechanics architecture on the DP4+ formalism (MM-DP4+). In addition, a Python applet (DP4+App) was developed to automate the entire process, requiring only the Gaussian NMR output files and a spreadsheet containing the experimental NMR data and labels. The script is designed to use the statistical parameters from the original 24 levels of theory (employing B3LYP/6-31G* geometries) and the new 36 levels explored in this work (over MMFF geometries). Furthermore, it enables the development of customizable methods using any desired level of theory, allowing for a free choice of test molecules.
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Affiliation(s)
- Bruno A Franco
- Instituto de Investigaciones en Ingeniería Ambiental, Química y Biotecnología Aplicada (INGEBIO), Facultad de Química e Ingeniería del Rosario, Pontificia Universidad Católica Argentina, Av. Pellegrini 3314, Rosario 2000, Argentina
| | - Ezequiel R Luciano
- Instituto de Investigaciones en Ingeniería Ambiental, Química y Biotecnología Aplicada (INGEBIO), Facultad de Química e Ingeniería del Rosario, Pontificia Universidad Católica Argentina, Av. Pellegrini 3314, 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
| | - María M Zanardi
- Instituto de Investigaciones en Ingeniería Ambiental, Química y Biotecnología Aplicada (INGEBIO), Facultad de Química e Ingeniería del Rosario, Pontificia Universidad Católica Argentina, Av. Pellegrini 3314, Rosario 2000, Argentina
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7
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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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8
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Carvalho DS, da Silva DGB, Hallwass F, Navarro-Vázquez A. An Acrylonitrile-Based Copolymer Gel as an NMR Alignment Medium for Extraction of Residual Dipolar Couplings of Small Molecules in Aqueous Solution. Chempluschem 2023; 88:e202200446. [PMID: 36782376 DOI: 10.1002/cplu.202200446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 01/19/2023] [Indexed: 01/24/2023]
Abstract
An NMR weakly-aligning polymer gel has been prepared by copolymerization of acrylonitrile and 2-acrylamide-2-methyl-1-propanesulfonic acid in the presence of 1,4-butanediol diacrylate as a cross-linker. The polymer readily swells in water in a large range of temperatures, although the swelling ratio is decreased in saline solutions. The swollen gel can be mechanically compressed, in a reversible way, generating anisotropy, as easily shown in 2 H NMR experiments, and allowing measurement of 1 DCH residual dipolar couplings (RDCs) through F1-coupled HSQC experiments. The performance of this gel as a NMR alignment medium was evaluated in several water-soluble organic molecules and, while it provided RDCs of proper size for sucrose and even such as small molecule as 5-norbornen-2-ol, in the case of azidothymidine and cefuroxime sodium salt the strong interaction of these molecules with the gel prevented successful extraction of the RDCs.
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Affiliation(s)
- Daiane S Carvalho
- Departamento de Química Fundamental, Universidade Federal de Pernambuco Cidade Universitria, CEP, 50.740-540, Recife, PE, Brazil
| | - Danilo G B da Silva
- Departamento de Química Fundamental, Universidade Federal de Pernambuco Cidade Universitria, CEP, 50.740-540, Recife, PE, Brazil
| | - Fernando Hallwass
- Departamento de Química Fundamental, Universidade Federal de Pernambuco Cidade Universitria, CEP, 50.740-540, Recife, PE, Brazil
| | - Armando Navarro-Vázquez
- Departamento de Química Fundamental, Universidade Federal de Pernambuco Cidade Universitria, CEP, 50.740-540, Recife, PE, Brazil
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9
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Epimeric Mixture Analysis and Absolute Configuration Determination Using an Integrated Spectroscopic and Computational Approach-A Case Study of Two Epimers of 6-Hydroxyhippeastidine. MOLECULES (BASEL, SWITZERLAND) 2022; 28:molecules28010214. [PMID: 36615407 PMCID: PMC9822407 DOI: 10.3390/molecules28010214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 11/26/2022] [Accepted: 12/22/2022] [Indexed: 12/28/2022]
Abstract
Structural elucidation has always been challenging, and misassignment remains a stringent issue in the field of natural products. The growing interest in discovering unknown, complex natural structures accompanies the increasing awareness concerning misassignments in the community. The combination of various spectroscopic methods with molecular modeling has gained popularity in recent years. In this work, we demonstrated, for the first time, its power to fully elucidate the 2-dimensional and 3-dimensional structures of two epimers in an epimeric mixture of 6-hydroxyhippeastidine. DFT calculation of chemical shifts was first performed to assist the assignment of planar structures. Furthermore, relative and absolute configurations were established by three different ways of computer-assisted structure elucidation (CASE) coupled with ORD/ECD/VCD spectroscopies. In addition, the significant added value of OR/ORD computations to relative and absolute configuration determination was also revealed. Remarkably, the differentiation of two enantiomeric scaffolds (crinine and haemanthamine) was accomplished via OR/ORD calculations with cross-validation by ECD and VCD.
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10
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Liu Y, Ndukwe IE, Reibarkh M, Martin GE, Williamson RT. Prediction of anisotropic NMR data without knowledge of alignment medium structure by surface decomposition. Phys Chem Chem Phys 2022; 24:20164-20182. [PMID: 35996986 DOI: 10.1039/d2cp02621j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Prediction of anisotropic NMR data directly from solute-medium interaction is of significant theoretical and practical interest, particularly for structure elucidation, configurational analysis and conformational studies of complex organic molecules and natural products. Current prediction methods require an explicit structural model of the alignment medium: a requirement either impossible or impractical on a scale necessary for small organic molecules. Here we formulate a comprehensive mathematical framework for a parametrization protocol that deconvolutes an arbitrary surface of the medium into several simple local landscapes that are distributed over the medium's surface by specific orientational order parameters. The shapes and order parameters of these local landscapes are determined via fitting that maximizes the congruence between experimentally determined anisotropic NMR measurables and their predicted counterparts, thus avoiding the need for an a priori knowledge of the global medium morphology. This method achieves substantial improvements in the accuracy of predicted anisotropic NMR values compared to current methods, as demonstrated herein with sixteen natural products. Furthermore, because this formalism extracts structural commonalities of the medium by combining anisotropic NMR data from different compounds, its robustness and accuracy are expected to improve as more experimental data become available for further re-optimization of fitting parameters.
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Affiliation(s)
- Yizhou Liu
- Analytical Research and Development, Pfizer Worldwide Research and Development, 445 Eastern Point Road, Groton, CT, 06340, USA.
| | - Ikenna E Ndukwe
- Analytical Research and Development, Merck & Co. Inc., 126 E. Lincoln Ave., Rahway, NJ, 07065, USA
| | - Mikhail Reibarkh
- Analytical Research and Development, Merck & Co. Inc., 126 E. Lincoln Ave., Rahway, NJ, 07065, USA
| | - Gary E Martin
- Analytical Research and Development, Merck & Co. Inc., 126 E. Lincoln Ave., Rahway, NJ, 07065, USA
| | - R Thomas Williamson
- Analytical Research and Development, Merck & Co. Inc., 126 E. Lincoln Ave., Rahway, NJ, 07065, USA
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11
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Li J, Tan YF, Liu S, Wu XQ, Wang J, Xu KP, Tan GS, Zou ZX, Wang WX. Reassignment of the structures of pestalopyrones A-D. PHYTOCHEMISTRY 2022; 200:113205. [PMID: 35436477 DOI: 10.1016/j.phytochem.2022.113205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 03/10/2022] [Accepted: 04/08/2022] [Indexed: 06/14/2023]
Abstract
Pestalopyrones A-D are four unusual tricyclic pyrone derivatives with flexible chiral structures, isolated from the endophytic fungus Pestalotiopsis neglecta S3. The full elucidation of their structures was a challenging task, and remained unsolved in the original article. Herein, the relative configurations of pestalopyrones A and pestalopyrones B were unambiguously assigned by detailed analyses on spectroscopic data and GIAO 13C NMR calculation method with sorted training sets (STS). The planar structures of pestalopyrones C and pestalopyrones D were revised by reinterpretation of their reported spectroscopic data, and then their relative configurations were deduced by STS GIAO 13C NMR calculation and NOE analysis. The absolute configurations of all the mentioned compounds were determined by the comparison of their experimental and calculated ECD curves.
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Affiliation(s)
- Jing Li
- Department of Pharmacy, Xiangya Hospital, PR China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, PR China
| | - Yu-Fen Tan
- Department of Pharmacy, Xiangya Hospital, PR China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, PR China
| | - Shao Liu
- Department of Pharmacy, Xiangya Hospital, PR China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, PR China
| | - Xiao-Qian Wu
- Xiangya School of Pharmaceutical Sciences, PR China; Hunan Key Laboratory of Diagnostic and Therapeutic Drug Research for Chronic Diseases, Central South University, Changsha, Hunan, 410008, PR China
| | - Jing Wang
- Xiangya School of Pharmaceutical Sciences, PR China; Hunan Key Laboratory of Diagnostic and Therapeutic Drug Research for Chronic Diseases, Central South University, Changsha, Hunan, 410008, PR China
| | - Kang-Ping Xu
- Xiangya School of Pharmaceutical Sciences, PR China; Hunan Key Laboratory of Diagnostic and Therapeutic Drug Research for Chronic Diseases, Central South University, Changsha, Hunan, 410008, PR China
| | - Gui-Shan Tan
- Department of Pharmacy, Xiangya Hospital, PR China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, PR China
| | - Zhen-Xing Zou
- Xiangya School of Pharmaceutical Sciences, PR China; Hunan Key Laboratory of Diagnostic and Therapeutic Drug Research for Chronic Diseases, Central South University, Changsha, Hunan, 410008, PR China
| | - Wen-Xuan Wang
- Xiangya School of Pharmaceutical Sciences, PR China; Hunan Key Laboratory of Diagnostic and Therapeutic Drug Research for Chronic Diseases, Central South University, Changsha, Hunan, 410008, PR China.
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12
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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: 4] [Impact Index Per Article: 2.0] [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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13
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Li XL, Ru T, Navarro-Vázquez A, Lindemann P, Nazaré M, Li XW, Guo YW, Sun H. Weizhouochrones: Gorgonian-Derived Symmetric Dimers and Their Structure Elucidation Using Anisotropic NMR Combined with DP4+ Probability and CASE-3D. JOURNAL OF NATURAL PRODUCTS 2022; 85:1730-1737. [PMID: 35792821 DOI: 10.1021/acs.jnatprod.2c00257] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Natural product dimers have intriguing structural features and often have remarkable pharmacological activities. We report here two uncommon marine gorgonian-derived symmetric dimers, weizhouochrones A (1) and B (2), with indenone-derived monomers, that were isolated from the coral Anthogorgia ochracea collected from the South China Sea. These dimers are difficult targets for structure elucidation that solely relies upon conventional NMR data such as NOEs and J-couplings. Here, to explore the application of emerging methods on the structure elucidation of challenging molecules, we explored a number of different anisotropic and computational NMR approaches. The measurements of anisotropic NMR parameters of weizhouochrone A, including residual dipolar couplings (RDCs) and residual chemical shift anisotropy (RCSA), allowed us to successfully determine the planar structure and its relative configuration. This result was corroborated by a computational NMR analysis based on DP4+ probability and computer-assisted 3D structure elucidation (CASE-3D).
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Affiliation(s)
- Xiao-Lu Li
- Group of Structural Chemistry and Computational Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin 13125, Germany
| | - Tong Ru
- 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
- University of Chinese Academy of Sciences, Yuquan Road 19A, Beijing 100049, China
| | - Armando Navarro-Vázquez
- Departamento de Química Fundamental, Universidade Federal de Pernambuco, 50670-901 Recife, PE, Brazil
| | - Peter Lindemann
- Group of Medicinal Chemistry, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin 13125, Germany
| | - Marc Nazaré
- Group of Medicinal Chemistry, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin 13125, Germany
| | - 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, China
- University of Chinese Academy of Sciences, Yuquan Road 19A, Beijing 100049, China
| | - 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, China
- University of Chinese Academy of Sciences, Yuquan Road 19A, Beijing 100049, China
| | - Han Sun
- Institute of Chemistry, Technical University of Berlin, Berlin 10623, Germany
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14
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Fuentes-Monteverde JCC, Nath N, Forero AM, Balboa EM, Navarro-Vázquez A, Griesinger C, Jiménez C, Rodríguez J. Connection of Isolated Stereoclusters by Combining 13C-RCSA, RDC, and J-Based Configurational Analyses and Structural Revision of a Tetraprenyltoluquinol Chromane Meroterpenoid from Sargassum muticum. Mar Drugs 2022; 20:462. [PMID: 35877755 PMCID: PMC9319238 DOI: 10.3390/md20070462] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 07/06/2022] [Accepted: 07/15/2022] [Indexed: 12/10/2022] Open
Abstract
The seaweed Sargassum muticum, collected on the southern coast of Galicia, yielded a tetraprenyltoluquinol chromane meroditerpene compound known as 1b, whose structure is revised. The relative configuration of 1b was determined by J-based configurational methodology combined with an iJ/DP4 statistical analysis and further confirmed by measuring two anisotropic properties: carbon residual chemical shift anisotropies (13C-RCSAs) and one-bond 1H-13C residual dipolar couplings (1DCH-RDCs). The absolute configuration of 1b was deduced by ECD/OR/TD-DFT methods and established as 3R,7S,11R.
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Affiliation(s)
- Juan Carlos C. Fuentes-Monteverde
- Departamento de Química e Centro de Investigacións Científicas Avanzadas (CICA), Universidade da Coruña, 15071 A Coruña, Spain; (J.C.C.F.-M.); (A.M.F.)
- NMR Based Structural Biology, MPI for Multidisciplinary Sciences, Am Fassberg 11, 37077 Göttingen, Germany
| | - Nilamoni Nath
- Department of Chemistry, Gauhati University, Gopinath Bardoloi Nagar, Guwahati 781014, India;
| | - Abel M. Forero
- Departamento de Química e Centro de Investigacións Científicas Avanzadas (CICA), Universidade da Coruña, 15071 A Coruña, Spain; (J.C.C.F.-M.); (A.M.F.)
| | - Elena M. Balboa
- Department of Chemical Engineering, Faculty of Science, Campus Ourense, University of Vigo, As Lagoas s/n, 32004 Ourense, Spain;
| | - Armando Navarro-Vázquez
- Departamento de Química Fundamental, CCEN, Universidade Federal de Pernambuco, Cidade Universitária, Recife 50740-550, Brazil;
| | - Christian Griesinger
- NMR Based Structural Biology, MPI for Multidisciplinary Sciences, Am Fassberg 11, 37077 Göttingen, Germany
| | - Carlos Jiménez
- Departamento de Química e Centro de Investigacións Científicas Avanzadas (CICA), Universidade da Coruña, 15071 A Coruña, Spain; (J.C.C.F.-M.); (A.M.F.)
| | - Jaime Rodríguez
- Departamento de Química e Centro de Investigacións Científicas Avanzadas (CICA), Universidade da Coruña, 15071 A Coruña, Spain; (J.C.C.F.-M.); (A.M.F.)
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15
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Yu G, Wang G, Duan M, Jiang B, Zhang X, Li C, He L, Liu M. Self-Assembled Oligopeptide (FK) 4 as a Chiral Alignment Medium for the Anisotropic NMR Analysis of Organic Compounds. ACS APPLIED MATERIALS & INTERFACES 2022; 14:29223-29229. [PMID: 35712808 DOI: 10.1021/acsami.2c05506] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Anisotropic NMR parameters have been proven to be powerful for the structural elucidation of organic molecules. Herein, we present an alignment medium based on the self-assembled (FK)4 oligopeptide, showing excellent properties in measurements of anisotropic NMR parameters in both D2O and CD3OD. The preparation of the (FK)4-based alignment medium is simple and rapid. The low viscosity of the anisotropic phase makes it easy to be transferred to the NMR tube. The alignment of the oligopeptide is fast, stable, and homogeneous, with weak background signals, permitting the acquirement of high-quality NMR spectra. The performance of this alignment medium in residual dipolar coupling measurements and diastereomer discriminations is demonstrated by analyzing several different analytes. The enantiodiscrimination property of the (FK)4 oligopeptide is revealed by the difference of residual chemical shift anisotropy of the two enantiomers in the 1D 13C spectrum, granting its potential use for the quantification and identification of enantiomers of small molecules.
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Affiliation(s)
- Gangjin Yu
- State Key Laboratory of Magnetic Resonance and Atomic Molecular Physics, Key Laboratory of Magnetic Resonance in Biological Systems, National Center for Magnetic Resonance in Wuhan, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Guan Wang
- State Key Laboratory of Magnetic Resonance and Atomic Molecular Physics, Key Laboratory of Magnetic Resonance in Biological Systems, National Center for Magnetic Resonance in Wuhan, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Mojie Duan
- State Key Laboratory of Magnetic Resonance and Atomic Molecular Physics, Key Laboratory of Magnetic Resonance in Biological Systems, National Center for Magnetic Resonance in Wuhan, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Bin Jiang
- State Key Laboratory of Magnetic Resonance and Atomic Molecular Physics, Key Laboratory of Magnetic Resonance in Biological Systems, National Center for Magnetic Resonance in Wuhan, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xu Zhang
- State Key Laboratory of Magnetic Resonance and Atomic Molecular Physics, Key Laboratory of Magnetic Resonance in Biological Systems, National Center for Magnetic Resonance in Wuhan, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Conggang Li
- State Key Laboratory of Magnetic Resonance and Atomic Molecular Physics, Key Laboratory of Magnetic Resonance in Biological Systems, National Center for Magnetic Resonance in Wuhan, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Lichun He
- State Key Laboratory of Magnetic Resonance and Atomic Molecular Physics, Key Laboratory of Magnetic Resonance in Biological Systems, National Center for Magnetic Resonance in Wuhan, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Maili Liu
- State Key Laboratory of Magnetic Resonance and Atomic Molecular Physics, Key Laboratory of Magnetic Resonance in Biological Systems, National Center for Magnetic Resonance in Wuhan, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Optics Valley Laboratory, Hubei 430074, China
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16
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Cumming IA, Degorce SL, Aagaard A, Braybrooke EL, Davies NL, Diène CR, Eatherton AJ, Felstead HR, Groombridge SD, Lenz EM, Li Y, Nai Y, Pearson S, Robb GR, Scott JS, Steward OR, Wu C, Xue Y, Zhang L, Zhang Y. Identification and optimisation of a pyrimidopyridone series of IRAK4 inhibitors. Bioorg Med Chem 2022; 63:116729. [PMID: 35439688 DOI: 10.1016/j.bmc.2022.116729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 03/23/2022] [Accepted: 03/28/2022] [Indexed: 12/01/2022]
Abstract
In this article, we report the discovery of a series of pyrimidopyridones as inhibitors of IRAK4 kinase. From a previously disclosed 5-azaquinazoline series, we found that switching the pyridine ring for an N-substituted pyridone gave a novel hinge binding scaffold which retained potency against IRAK4. Importantly, introduction of the carbonyl established an internal hydrogen bond with the 4-NH, establishing a conformational lock and allowing truncation of the large basic substituent to a 1-methylcyclopyl group. Subsequent optimisation, facilitated by X-ray crystal structures, allowed identification of preferred substituents at both the pyridone core and pyrazole. Subsequent combinations of optimal groups allowed control of lipophilicity and identification of potent and selective inhibitors of IRAK4 with better in vitro permeability and lower clearance.
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Affiliation(s)
- Iain A Cumming
- Medicinal Chemistry, Research and Early Development, Oncology R&D, AstraZeneca, Cambridge Science Park, Unit 310 Darwin Building, Cambridge CB4 0WG, United Kingdom.
| | - Sébastien L Degorce
- Medicinal Chemistry, Research and Early Development, Oncology R&D, AstraZeneca, Cambridge Science Park, Unit 310 Darwin Building, Cambridge CB4 0WG, United Kingdom
| | - Anna Aagaard
- Discovery Sciences, R&D, AstraZeneca, Gothenburg, SE-431 83 Mölndal, Sweden
| | - Erin L Braybrooke
- Medicinal Chemistry, Research and Early Development, Oncology R&D, AstraZeneca, Cambridge Science Park, Unit 310 Darwin Building, Cambridge CB4 0WG, United Kingdom
| | - Nichola L Davies
- Medicinal Chemistry, Research and Early Development, Oncology R&D, AstraZeneca, Cambridge Science Park, Unit 310 Darwin Building, Cambridge CB4 0WG, United Kingdom
| | - Coura R Diène
- Medicinal Chemistry, Research and Early Development, Oncology R&D, AstraZeneca, Cambridge Science Park, Unit 310 Darwin Building, Cambridge CB4 0WG, United Kingdom
| | - Andrew J Eatherton
- Medicinal Chemistry, Research and Early Development, Oncology R&D, AstraZeneca, Cambridge Science Park, Unit 310 Darwin Building, Cambridge CB4 0WG, United Kingdom
| | - Hannah R Felstead
- Medicinal Chemistry, Research and Early Development, Oncology R&D, AstraZeneca, Cambridge Science Park, Unit 310 Darwin Building, Cambridge CB4 0WG, United Kingdom
| | - Sam D Groombridge
- Medicinal Chemistry, Research and Early Development, Oncology R&D, AstraZeneca, Cambridge Science Park, Unit 310 Darwin Building, Cambridge CB4 0WG, United Kingdom
| | - Eva M Lenz
- Medicinal Chemistry, Research and Early Development, Oncology R&D, AstraZeneca, Cambridge Science Park, Unit 310 Darwin Building, Cambridge CB4 0WG, United Kingdom
| | - Yunxia Li
- Pharmaron Beijing Co., Ltd., 6 Taihe Road BDA, Beijing 100176 PR China
| | - Youfeng Nai
- Pharmaron Beijing Co., Ltd., 6 Taihe Road BDA, Beijing 100176 PR China
| | - Stuart Pearson
- Medicinal Chemistry, Research and Early Development, Oncology R&D, AstraZeneca, Cambridge Science Park, Unit 310 Darwin Building, Cambridge CB4 0WG, United Kingdom
| | - Graeme R Robb
- Medicinal Chemistry, Research and Early Development, Oncology R&D, AstraZeneca, Cambridge Science Park, Unit 310 Darwin Building, Cambridge CB4 0WG, United Kingdom
| | - James S Scott
- Medicinal Chemistry, Research and Early Development, Oncology R&D, AstraZeneca, Cambridge Science Park, Unit 310 Darwin Building, Cambridge CB4 0WG, United Kingdom
| | - Oliver R Steward
- Medicinal Chemistry, Research and Early Development, Oncology R&D, AstraZeneca, Cambridge Science Park, Unit 310 Darwin Building, Cambridge CB4 0WG, United Kingdom
| | - Chengyan Wu
- Pharmaron Beijing Co., Ltd., 6 Taihe Road BDA, Beijing 100176 PR China
| | - Yafeng Xue
- Discovery Sciences, R&D, AstraZeneca, Gothenburg, SE-431 83 Mölndal, Sweden
| | - Lanping Zhang
- Pharmaron Beijing Co., Ltd., 6 Taihe Road BDA, Beijing 100176 PR China
| | - Yanxiu Zhang
- Pharmaron Beijing Co., Ltd., 6 Taihe Road BDA, Beijing 100176 PR China
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17
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Sternberg U, Farès C. Statistical evaluation of simulated NMR data of flexible molecules. Phys Chem Chem Phys 2022; 24:9608-9618. [PMID: 35403649 DOI: 10.1039/d2cp00330a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A new probability score-named χ-probability-is introduced for evaluating the fit of mixed NMR datasets to calculate molecular model ensembles, in order to answer challenging structural questions such as the determination of stereochemical configurations. Similar to the DP4 parameter, the χ-probability is based on Bayes theorem and expresses the probability that an experimental NMR dataset fits to a given individual within a finite set of candidate structures or configurations. Here, the χ-probability is applied to single out the correct configuration in four example cases, with increasing complexity and conformational mobility. The NMR data (which include RDCs, NOE distances and 3J couplings) are calculated from MDOC (Molecular Dynamics with Orientational Constraints) trajectories and are investigated against experimentally measured data. It is demonstrated that this approach singles out the correct stereochemical configuration with probabilities more than 98%, even for highly mobile molecules. In more demanding cases, a decisive χ-probability test requires that the datasets include high-quality NOE distances in addition to RDC values.
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Affiliation(s)
- Ulrich Sternberg
- Research Partner of Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany. .,COSMOS-Software, Jena, Germany
| | - Christophe Farès
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm Platz 1, 45470 Mülheim an der Ruhr, Germany.
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18
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Immel S, Köck M, Reggelin M. Bayesian Inference Applied to NMR-Based Configurational Assignments by Floating Chirality Distance Geometry Calculations. J Am Chem Soc 2022; 144:6830-6838. [PMID: 35412312 DOI: 10.1021/jacs.2c00813] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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 quality and probability of structural elucidations using Bayesian inference in combination with floating chirality distance geometry simulations. Here, we will discuss the configurational analysis of three complex natural products including isopinocampheol (1), plakilactone H (2), and iodocallophycoic acid A (3) using NMR restraints of various types and in different combinations (residual dipolar couplings (RDCs) and NOE-derived distances). Our results quantitatively demonstrate how reliably molecular geometries can be inferred from experimental NMR data, unequivocally unveiling remaining assignment ambiguities. The methodology presented here can dramatically reduce the risk of incorrect structural assignments based on the overinterpretation of incomplete data 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- and 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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19
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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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20
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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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21
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Fumagalli G, Carbajo RJ, Nissink JWM, Tart J, Dou R, Thomas AP, Spring DR. Targeting a Novel KRAS Binding Site: Application of One-Component Stapling of Small (5-6-mer) Peptides. J Med Chem 2021; 64:17287-17303. [PMID: 34787423 DOI: 10.1021/acs.jmedchem.1c01334] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
RAS proteins are central in the proliferation of many types of cancer, but a general approach toward the identification of pan-mutant RAS inhibitors has remained unresolved. In this work, we describe the application of a binding pharmacophore identified from analysis of known RAS binding peptides to the design of novel peptides. Using a chemically divergent approach, we generated a library of small stapled peptides from which we identified compounds with weak binding activity. Exploration of structure-activity relationships (SARs) and optimization of these early compounds led to low-micromolar binders of KRAS that block nucleotide exchange.
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Affiliation(s)
- Gabriele Fumagalli
- Department of Chemistry, Cambridge University, Lensfield Road, Cambridge CB2 1EW, U.K.,Chemistry, Oncology R&D, AstraZeneca, Cambridge CB4 0WG, U.K
| | | | | | - Jonathan Tart
- Discovery Sciences, BioPharmaceuticals R&D, AstraZeneca, Cambridge CB4 0WG, U.K
| | - Rongxuan Dou
- Department of Chemistry, Cambridge University, Lensfield Road, Cambridge CB2 1EW, U.K
| | - Andrew P Thomas
- Chemistry, Oncology R&D, AstraZeneca, Cambridge CB4 0WG, U.K
| | - David R Spring
- Department of Chemistry, Cambridge University, Lensfield Road, Cambridge CB2 1EW, U.K
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22
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Farley KA, Koos MRM, Che Y, Horst R, Limberakis C, Bellenger J, Lira R, Gil-Silva LF, Gil RR. Cross-Linked Poly-4-Acrylomorpholine: A Flexible and Reversibly Compressible Aligning Gel for Anisotropic NMR Analysis of Peptides and Small Molecules in Water. Angew Chem Int Ed Engl 2021; 60:26314-26319. [PMID: 34609778 DOI: 10.1002/anie.202106794] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Indexed: 11/07/2022]
Abstract
Determination of the solution conformation of both small organic molecules and peptides in water remains a substantial hurdle in using NMR solution conformations to guide drug design due to the lack of easy to use alignment media. Herein we report the design of a flexible compressible chemically cross-linked poly-4-acrylomorpholine gel that can be used for the alignment of both small molecules and cyclic peptides in water. To test the new gel, residual dipolar couplings (RDCs) and J-coupling constants were used in the configurational analysis of strychnine hydrochloride, a molecule that has been studied extensively in organic solvents as well as a small cyclic peptide that is known to form an α-helix in water. The conformational ensembles for each molecule with the best fit to the data are reported. Identification of minor conformers in water that cannot easily be determined by conventional NOE measurements will facilitate the use of RDC experiments in structure-based drug design.
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Affiliation(s)
- Kathleen A Farley
- Medicinal Sciences, Pfizer, Eastern Point Road, Groton, CT, 06340, USA
| | - Martin R M Koos
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA, 15213, USA
| | - Ye Che
- Medicinal Sciences, Pfizer, Eastern Point Road, Groton, CT, 06340, USA
| | - Reto Horst
- Medicinal Sciences, Pfizer, Eastern Point Road, Groton, CT, 06340, USA
| | - Chris Limberakis
- Medicinal Sciences, Pfizer, Eastern Point Road, Groton, CT, 06340, USA
| | - Justin Bellenger
- Medicinal Sciences, Pfizer, Eastern Point Road, Groton, CT, 06340, USA
| | - Ricardo Lira
- Medicinal Sciences, Pfizer, Eastern Point Road, Groton, CT, 06340, USA
| | | | - Roberto R Gil
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA, 15213, USA
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23
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Farley KA, Koos MRM, Che Y, Horst R, Limberakis C, Bellenger J, Lira R, Gil‐Silva LF, Gil RR. Cross‐Linked Poly‐4‐Acrylomorpholine: A Flexible and Reversibly Compressible Aligning Gel for Anisotropic NMR Analysis of Peptides and Small Molecules in Water. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202106794] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
| | - Martin R. M. Koos
- Department of Chemistry Carnegie Mellon University 4400 Fifth Avenue Pittsburgh PA 15213 USA
| | - Ye Che
- Medicinal Sciences Pfizer Eastern Point Road Groton CT 06340 USA
| | - Reto Horst
- Medicinal Sciences Pfizer Eastern Point Road Groton CT 06340 USA
| | - Chris Limberakis
- Medicinal Sciences Pfizer Eastern Point Road Groton CT 06340 USA
| | - Justin Bellenger
- Medicinal Sciences Pfizer Eastern Point Road Groton CT 06340 USA
| | - Ricardo Lira
- Medicinal Sciences Pfizer Eastern Point Road Groton CT 06340 USA
| | | | - Roberto R. Gil
- Department of Chemistry Carnegie Mellon University 4400 Fifth Avenue Pittsburgh PA 15213 USA
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24
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Poveda A, Fittolani G, Seeberger PH, Delbianco M, Jiménez-Barbero J. The Flexibility of Oligosaccharides Unveiled Through Residual Dipolar Coupling Analysis. Front Mol Biosci 2021; 8:784318. [PMID: 34859057 PMCID: PMC8631391 DOI: 10.3389/fmolb.2021.784318] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 10/14/2021] [Indexed: 11/13/2022] Open
Abstract
The intrinsic flexibility of glycans complicates the study of their structures and dynamics, which are often important for their biological function. NMR has provided insights into the conformational, dynamic and recognition features of glycans, but suffers from severe chemical shift degeneracy. We employed labelled glycans to explore the conformational behaviour of a β(1-6)-Glc hexasaccharide model through residual dipolar couplings (RDCs). RDC delivered information on the relative orientation of specific residues along the glycan chain and provided experimental clues for the existence of certain geometries. The use of two different aligning media demonstrated the adaptability of flexible oligosaccharide structures to different environments.
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Affiliation(s)
- Ana Poveda
- CICbioGUNE, Basque Research and Technology Alliance (BRTA), Derio, Spain
| | - Giulio Fittolani
- Department of Biomolecular Systems, Max-Planck-Institute of Colloids and Interfaces, Potsdam, Germany.,Department of Chemistry and Biochemistry, Freie Universität Berlin, Berlin, Germany
| | - Peter H Seeberger
- Department of Biomolecular Systems, Max-Planck-Institute of Colloids and Interfaces, Potsdam, Germany.,Department of Chemistry and Biochemistry, Freie Universität Berlin, Berlin, Germany
| | - Martina Delbianco
- Department of Biomolecular Systems, Max-Planck-Institute of Colloids and Interfaces, Potsdam, Germany
| | - Jesús Jiménez-Barbero
- CICbioGUNE, Basque Research and Technology Alliance (BRTA), Derio, Spain.,Ikerbasque, Basque Foundation for Science, Bilbao, Spain.,Department of Organic Chemistry II, Faculty of Science and Technology, University of the Basque Country, EHU-UPV, Leioa, Spain.,Centro de Investigacion Biomedica En Red de Enfermedades Respiratorias, Madrid, Spain
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25
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Navarro-Vázquez A. Computational Structural Revision of a 4-Hydroxy-3-(1'-angeloyloxy-2',3'-epoxy-3'-methyl)butylacetophenone Compound from Ageratina grandifolia. JOURNAL OF NATURAL PRODUCTS 2021; 84:2043-2047. [PMID: 34192466 DOI: 10.1021/acs.jnatprod.1c00398] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The structure of the reported compound 4-hydroxy-3-((S)-1'-angeloyloxy-(R)-2',3'-epoxy-3'-methyl)butylacetophenone (1), isolated from Ageratina grandifolia, has been revised through the use of DFT computational predictions. Re-examination of the reported experimental and DFT computed chemical shifts has led to the proposal of a chromane skeleton rather than the original epoxide derivative. Empirical predictions of the 13C and 1H NMR shifts showed a much better fit for the chromane structure than for the epoxide. The relative configuration of the molecule was established using CASE-3D methodology on the basis of new DFT chemical shielding and J-coupling predictions, allowing the proposal of a new rel-2,2-dimethyl-3R-hydroxy-4S-(1-angeloyloxy)chromane structure (2) for the isolated compound. However, DFT prediction of the optical rotation for the CASE-3D selected configuration/conformations did not provide a conclusive answer for the absolute configuration.
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Affiliation(s)
- Armando Navarro-Vázquez
- Departamento de Química Fundamental, Universidade Federal de Pernambuco, Avenida Professor Moraes Rego, 1235, Cidade Universitária, 50670-901, Recife, PE, Brazil
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26
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Marcarino MO, Cicetti S, Zanardi MM, Sarotti AM. A critical review on the use of DP4+ in the structural elucidation of natural products: the good, the bad and the ugly. A practical guide. Nat Prod Rep 2021; 39:58-76. [PMID: 34212963 DOI: 10.1039/d1np00030f] [Citation(s) in RCA: 71] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Covering: 2015 up to the end of 2020Even in the golden age of NMR, the number of natural products being incorrectly assigned is becoming larger every day. The use of quantum NMR calculations coupled with sophisticated data analysis provides ideal complementary tools to facilitate the elucidation process in challenging cases. Among the current computational methodologies to perform this task, the DP4+ probability is a popular and widely used method. This updated version of Goodman's DP4 synergistically combines NMR calculations at higher levels of theory with the Bayesian analysis of both scaled and unscaled data. Since its publication in late 2015, the use of DP4+ to solve controversial natural products has substantially grown, with several predictions being confirmed by total synthesis. To date, the structures of more than 200 natural products were determined with the aid of DP4+. However, all that glitters is not gold. Besides its intrinsic limitations, on many occasions it has been improperly used with potentially important consequences on the quality of the assignment. Herein we present a critical revision on how the scientific community has been using DP4+, exploring the strengths of the method and how to obtain optimal results from it. We also analyze the weaknesses of DP4+, and the paths to by-pass them to maximize the confidence in the structural elucidation.
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Affiliation(s)
- Maribel O Marcarino
- Instituto de Química Rosario (CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, Rosario 2000, Argentina.
| | - Soledad Cicetti
- Instituto de Química Rosario (CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, Rosario 2000, Argentina.
| | - María M Zanardi
- Instituto de Ingeniería Ambiental, Química y Biotecnología Aplicada (INGEBIO), Facultad de Química e Ingeniería del Rosario, Pontificia Universidad Católica Argentina, Av. Pellegrini 3314, 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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27
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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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28
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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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29
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Burns DC, Reynolds WF. Minimizing the risk of deducing wrong natural product structures from NMR data. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2021; 59:500-533. [PMID: 33855734 DOI: 10.1002/mrc.4933] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2019] [Revised: 07/31/2019] [Accepted: 08/01/2019] [Indexed: 06/12/2023]
Abstract
There continues to be a disturbing number of natural products reported in the literature whose structures are incorrect. At least in part, this reflects the fact that many natural product chemists have limited formal nuclear magnetic resonance training. Gaps in training and lack of awareness regarding the challenges and ambiguities associated with two-dimensional nuclear magnetic resonance data interpretation can easily lead to errors in structure elucidation. The purpose of this tutorial is to point out some of these issues, highlight the kinds of errors that have been made and provide specific advice on how to avoid these missteps such that the risk of reporting a wrong structure is minimized.
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Affiliation(s)
- Darcy C Burns
- Department of Chemistry, University of Toronto, Toronto, Ontario, Canada
| | - William F Reynolds
- Department of Chemistry, University of Toronto, Toronto, Ontario, Canada
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30
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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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31
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de Melo Sousa CM, Giordani RB, de Almeida WAM, Griesinger C, Gil RR, Navarro-Vázquez A, Hallwass F. Effect of the solvent on the conformation of monocrotaline as determined by isotropic and anisotropic NMR parameters. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2021; 59:561-568. [PMID: 31715029 DOI: 10.1002/mrc.4968] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 10/25/2019] [Accepted: 11/04/2019] [Indexed: 06/10/2023]
Abstract
The conformation in solution of monocrotaline, a pyrrolizidine alkaloid presenting an eleven-membered macrocyclic diester ring, has been investigated using a combination of isotropic and anisotropic nuclear magnetic resonance parameters measured in four solvents of different polarity (D2 O, DMSO-d6 , CDCl3 , and C6 D6 ). Anisotropic nuclear magnetic resonance parameters were measured in different alignment media, based on their compatibility with the solvent of interest: cromoglycate liquid crystal solution was used for D2 O, whereas a poly (methyl methacrylate) polymer gel was chosen for CDCl3 and C6 D6 , and a poly (hydroxyethyl methacrylate) gel for DMSO-d6 . Whereas the pyrrolizidine ring shows an E6 exo-puckered conformation in all of the solvents, the macrocyclic eleven-membered ring adopts different populations of syn-parallel and anti-parallel relative orientation of the carbonyl groups according to the polarity of the solvent.
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Affiliation(s)
- Cleyton Marcos de Melo Sousa
- Departamento de Química Fundamental, Universidade Federal de Pernambuco, Recife, Pernambuco, Brazil
- Instituto Federal de Pernambuco, Caruaru, Pernambuco, Brazil
| | - Raquel Brandt Giordani
- Laboratório de Farmacognosia, Departamento de Farmácia, Universidade Federal do Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil
| | | | - Christian Griesinger
- Abteilung für NMR-basierte Strukturbiologie, Max-Planck-Institut für Biophysikalische Chemie, Göttingen, Germany
| | - Roberto R Gil
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania
| | - Armando Navarro-Vázquez
- Departamento de Química Fundamental, Universidade Federal de Pernambuco, Recife, Pernambuco, Brazil
| | - Fernando Hallwass
- Departamento de Química Fundamental, Universidade Federal de Pernambuco, Recife, Pernambuco, Brazil
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32
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Ai Y, Hwang L, MacKerell AD, Melnick A, Xue F. Progress toward B-Cell Lymphoma 6 BTB Domain Inhibitors for the Treatment of Diffuse Large B-Cell Lymphoma and Beyond. J Med Chem 2021; 64:4333-4358. [PMID: 33844535 DOI: 10.1021/acs.jmedchem.0c01686] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
B-cell lymphoma 6 (BCL6) is a master regulator of germinal center formation that produce antibody-secreting plasma cells and memory B-cells for sustained immune responses. The BTB domain of BCL6 (BCL6BTB) forms a homodimer that mediates transcriptional repression by recruiting its corepressor proteins to form a biologically functional transcriptional complex. The protein-protein interaction (PPI) between the BCL6BTB and its corepressors has emerged as a therapeutic target for the treatment of DLBCL and a number of other human cancers. This Perspective provides an overview of recent advances in the development of BCL6BTB inhibitors from reversible inhibitors, irreversible inhibitors, to BCL6 degraders. Inhibitor design and medicinal chemistry strategies for the development of novel compounds will be provided. The binding mode of new inhibitors to BCL6BTB are highlighted. Also, the in vitro and in vivo assays used for the evaluation of new compounds will be discussed.
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Affiliation(s)
- Yong Ai
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, 20 Penn Street, Baltimore, Maryland 21201, United States
| | - Lucia Hwang
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, 20 Penn Street, Baltimore, Maryland 21201, United States
| | - Alexander D MacKerell
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, 20 Penn Street, Baltimore, Maryland 21201, United States
| | - Ari Melnick
- Department of Hematology and Oncology, Weill Cornell Medical College, New York, New York 10021, United States.,Department of Pharmacology, Weill Cornell Medical College, New York, New York 10021, United States
| | - Fengtian Xue
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, 20 Penn Street, Baltimore, Maryland 21201, United States
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33
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Ding CF, Yu HF, Shi XL, Ge SC, Njateng GS, Qin XJ, Dai Z, Zhang RP, Zhang HB, Luo XD. Rapid and unambiguous assignment of proton-deficient N-acyl amidine indole alkaloid by a combination of calculation methods. Tetrahedron Lett 2021. [DOI: 10.1016/j.tetlet.2021.152949] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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34
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Reggelin M, Immel S. Configurational Analysis by Residual Dipolar Couplings: Critical Assessment of "Structural Noise" from Thermal Vibrations. Angew Chem Int Ed Engl 2021; 60:3412-3416. [PMID: 33137233 PMCID: PMC7898695 DOI: 10.1002/anie.202011081] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Indexed: 12/11/2022]
Abstract
The certainty of configurational assignments of natural products based on anisotropic NMR parameters, such as residual dipolar couplings (RDCs), must be amended by estimates on structural noise emerging from thermal vibrations. We show that vibrational analysis significantly affects the error margins with which RDCs can be back-calculated from molecular models, and the implications of thermal motions on the differentiability of diastereomers are derived.
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Affiliation(s)
- Michael Reggelin
- Technische Universität DarmstadtClemens Schöpf Institut für Organische Chemie und BiochemieAlarich-Weiss-Strasse 464287DarmstadtGermany
| | - Stefan Immel
- Technische Universität DarmstadtClemens Schöpf Institut für Organische Chemie und BiochemieAlarich-Weiss-Strasse 464287DarmstadtGermany
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35
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Reggelin M, Immel S. Configurational Analysis by Residual Dipolar Couplings: Critical Assessment of “Structural Noise” from Thermal Vibrations. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202011081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Michael Reggelin
- Technische Universität Darmstadt Clemens Schöpf Institut für Organische Chemie und Biochemie Alarich-Weiss-Strasse 4 64287 Darmstadt Germany
| | - Stefan Immel
- Technische Universität Darmstadt Clemens Schöpf Institut für Organische Chemie und Biochemie Alarich-Weiss-Strasse 4 64287 Darmstadt Germany
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36
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Monroe AZ, Gordon WH, Wood JS, Martin GE, Morgan JB, Williamson RT. Structural revision of a Wnt/β-catenin modulator and confirmation of cannabielsoin constitution and configuration. Chem Commun (Camb) 2021; 57:5658-5661. [DOI: 10.1039/d1cc01971f] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
In this report, we revise the structure for a previously reported synthetic product proposed to be the 1R,2S-cannabidiol epoxide and reassign it as cannabielsoin using anisotropic NMR and synthetic chemistry methods.
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Affiliation(s)
- Angelina Z. Monroe
- Department of Chemistry & Biochemistry
- University of North Carolina Wilmington
- Wilmington
- USA
| | - William H. Gordon
- Department of Chemistry & Biochemistry
- University of North Carolina Wilmington
- Wilmington
- USA
| | - Jared S. Wood
- Department of Chemistry & Biochemistry
- University of North Carolina Wilmington
- Wilmington
- USA
| | - Gary E. Martin
- Department of Chemistry
- Seton Hall University
- South Orange
- USA
| | - Jeremy B. Morgan
- Department of Chemistry & Biochemistry
- University of North Carolina Wilmington
- Wilmington
- USA
| | - R. Thomas Williamson
- Department of Chemistry & Biochemistry
- University of North Carolina Wilmington
- Wilmington
- USA
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37
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Recchia MJJ, Cohen RD, Liu Y, Sherer EC, Harper JK, Martin GE, Williamson RT. "One-Shot" Measurement of Residual Chemical Shift Anisotropy Using Poly-γ-benzyl-l-glutamate as an Alignment Medium. Org Lett 2020; 22:8850-8854. [PMID: 33140974 DOI: 10.1021/acs.orglett.0c03225] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
A method for the measurement of residual chemical shift anisotropy in one experiment using a biphasic isotropic/anisotropic lyotropic liquid crystalline medium based on poly-γ-benzyl-l-glutamate as the alignment medium is presented. This approach is demonstrated on the model compound strychnine and neotricone, a depsidone natural product with a questionable structural assignment based on comparison with the closely related excelsione and in-depth density functional theory calculations.
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Affiliation(s)
- Michael J J Recchia
- Department of Chemistry & Biochemistry, University of North Carolina Wilmington, Wilmington, North Carolina 28409, United States
| | - Ryan D Cohen
- Analytical Research & Development, Merck & Company Inc., Rahway, New Jersey 07065, United States
| | - Yizhou Liu
- Analytical Research & Development, Pfizer Worldwide Research and Development, Groton, Connecticut 06340, United States
| | - Edward C Sherer
- Analytical Research & Development, Merck & Company Inc., Rahway, New Jersey 07065, United States
| | - James K Harper
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, United States
| | - Gary E Martin
- Department of Chemistry, Seton Hall University, South Orange, New Jersey 07079, United States
| | - R Thomas Williamson
- Department of Chemistry & Biochemistry, University of North Carolina Wilmington, Wilmington, North Carolina 28409, United States
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38
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Sager E, Tzvetkova P, Gossert AD, Piechon P, Luy B. Determination of Configuration and Conformation of a Reserpine Derivative with Seven Stereogenic Centers Using Molecular Dynamics with RDC-Derived Tensorial Constraints*. Chemistry 2020; 26:14435-14444. [PMID: 32744785 PMCID: PMC7702126 DOI: 10.1002/chem.202002642] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 07/22/2020] [Indexed: 11/11/2022]
Abstract
NMR-based determination of the configuration of complex molecules containing many stereocenters is often not possible using traditional NOE data and coupling patterns. Making use of residual dipolar couplings (RDCs), we were able to determine the relative configuration of a natural product containing seven stereocenters, including a chiral amine lacking direct RDC data. To identify the correct relative configuration out of 32 possible ones, experimental RDCs were used in three different approaches for data interpretation: by fitting experimental data based singular value decomposition (SVD) using a single alignment tensor and either (i) a single conformer or (ii) multiple conformers, or alternatively (iii) using molecular dynamics simulations with tensorial orientational constraints (MDOC). Even though in all three approaches one and the same configuration could be selected and clear discrimination between possible configurations was achieved, the experimental data was not fully satisfied by the methods based on single tensor approaches. While these two approaches are faster, only MDOC is able to fully reproduce experimental results, as the obtained conformational ensemble adequately covers the conformational space necessary to describe the molecule with inherent flexibility.
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Affiliation(s)
- Emine Sager
- Institut für Organische ChemieKarlsruher Institut für Technologie (KIT)Fritz-Haber-Weg 676131KarlsruheGermany
- Novartis Pharma AGNovartis Institutes for Biomedical Research4002BaselSwitzerland
| | - Pavleta Tzvetkova
- Institut für Biologische Grenzflächen 4—Magnetische ResonanzKarlsruher Institut für Technologie (KIT)Postfach 364076021KarlsruheGermany
| | - Alvar D. Gossert
- Novartis Pharma AGNovartis Institutes for Biomedical Research4002BaselSwitzerland
- Institut für Molekularbiologie und BiophysikETH Zürich8093ZürichSwitzerland
| | - Philippe Piechon
- Novartis Pharma AGNovartis Institutes for Biomedical Research4002BaselSwitzerland
| | - Burkhard Luy
- Institut für Organische ChemieKarlsruher Institut für Technologie (KIT)Fritz-Haber-Weg 676131KarlsruheGermany
- Institut für Biologische Grenzflächen 4—Magnetische ResonanzKarlsruher Institut für Technologie (KIT)Postfach 364076021KarlsruheGermany
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39
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Jia W, Yang Z, Yang M, Cheng L, Lei Z, Wang X. Machine Learning Enhanced Spectrum Recognition Based on Computer Vision (SRCV) for Intelligent NMR Data Extraction. J Chem Inf Model 2020; 61:21-25. [PMID: 33170690 DOI: 10.1021/acs.jcim.0c01046] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A machine learning enhanced spectrum recognition system called spectrum recognition based on computer vision (SRCV) for data extraction from previously analyzed 13C and 1H NMR spectra has been developed. The intelligent system was designed with four function modules to extract data from three areas of NMR images, including 13C and 1H chemical shifts, the integral, and the range of the shift values. During this study, three machine learning models were pretrained for number recognition, which is the key procedure for NMR data extraction. The k nearest neighbor (kNN) method was selected with optimized k (k = 4), which displayed a 100% recognition rate. Subsequently, the performance of SRCV was tested and validated to have high accuracy with a short processing time (11-21 s) for each NMR spectral image. Our spectrum recognizer enables high-throughput 13C and 1H NMR data extraction from abundant spectra in the literature and has the potential to be used for spectral database construction. In addition, the system may be applicable to be developed for data import to computer-assisted structure elucidation systems, which would automate this procedure significantly. SRCV can be accessed in GitHub (https://github.com/WJmodels/SRCV).
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Affiliation(s)
- Wenqiang Jia
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Department of Medicinal Chemistry, Beijing Key Laboratory of Active Substances Discovery and Druggability Evaluation, Institute of Materia Medica, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing 100050, China
| | - Zhuo Yang
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Department of Medicinal Chemistry, Beijing Key Laboratory of Active Substances Discovery and Druggability Evaluation, Institute of Materia Medica, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing 100050, China
| | - Minjian Yang
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Department of Medicinal Chemistry, Beijing Key Laboratory of Active Substances Discovery and Druggability Evaluation, Institute of Materia Medica, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing 100050, China
| | - Liang Cheng
- Golden Intelligence Cloud Co., Ltd., Guangzhou 510000, China
| | - Zengrong Lei
- Guangzhou Fermion Technology Co., Ltd., Guangzhou 510000, China
| | - Xiaojian Wang
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Department of Medicinal Chemistry, Beijing Key Laboratory of Active Substances Discovery and Druggability Evaluation, Institute of Materia Medica, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing 100050, China
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40
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Lesot P, Gil RR, Berdagué P, Navarro-Vázquez A. Deuterium Residual Quadrupolar Couplings: Crossing the Current Frontiers in the Relative Configuration Analysis of Natural Products. JOURNAL OF NATURAL PRODUCTS 2020; 83:3141-3148. [PMID: 32970418 DOI: 10.1021/acs.jnatprod.0c00745] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The determination of the 3D structure (configuration and preferred conformation) of complex natural and synthetic organic molecules is a long-standing but still challenging task for chemists, with various implications in pharmaceutical sciences whether or not these substances have specific bioactivities. Nuclear magnetic resonance (NMR) in aligning media, either lyotropic liquid crystals (LLCs) or polymer gels, in combination with molecular modeling is a unique framework for solving complex structural problems whose analytical wealth lies in the establishment of nonlocal structural correlations. As an alternative to the already well-established anisotropic NMR parameters, such as RDCs (residual dipolar couplings) and RCSAs (residual chemical shift anisotropies), it is shown here that deuterium residual quadrupolar couplings (2H-RQCs) can be extracted from 2H 2D-NMR spectra recorded at the natural abundance level in samples oriented in a homopolypeptide LLCs (poly-γ-benzyl-l-glutamate (PBLG)). These 2H-RQCs were successfully used to address nontrivial structural problems in organic molecules. The performance and scope of this new tool is examined for two natural chiral compounds of pharmaceutical interest (strychnine and artemisinin). This is the first report in which the 3D structure/relative configuration of complex bioactive molecules is unambiguously determined using only 2H-RQCs, which, in this case, are at 2H natural abundance.
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Affiliation(s)
- Philippe Lesot
- Université Paris-Saclay, UFR d'Orsay, RMN en Milieu Orienté, ICMMO, UMR CNRS 8182, Bât. 410, 15 rue du Doyen, Georges Poitou, F-91405 Orsay, France
- Centre National de la Recherche Scientifique (CNRS), 3 rue Michel Ange, F-75016 Paris, France
| | - Roberto R Gil
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Philippe Berdagué
- Université Paris-Saclay, UFR d'Orsay, RMN en Milieu Orienté, ICMMO, UMR CNRS 8182, Bât. 410, 15 rue du Doyen, Georges Poitou, F-91405 Orsay, France
| | - Armando Navarro-Vázquez
- Departamento de Química Fundamental, Universidade Federal de Pernambuco, Cidade Universitária, CEP 50.740-540 Recife, Pernambuco, Brazil
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41
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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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42
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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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43
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Abstract
Nuclear Overhauser Effect (NOE) methods in NMR are an important tool for 3D structural analysis of small molecules. Quantitative NOE methods conventionally rely on reference distances, known distances that have to be spectrally separated and are not always available. Here we present a new method for evaluation and 3D structure selection that does not require a reference distance, instead utilizing structures optimized by molecular mechanics, enabling NOE evaluation even on molecules without suitable reference groups. A quantitative Nuclear Overhauser Effect (NOE) analysis approach that avoids the use of and internal reference distance to perform molecular configuration selection.![]()
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Affiliation(s)
- Martin R M Koos
- Department of Chemistry, Carnegie Mellon University 4400 Fifth Avenue Pittsburgh Pennsylvania 15213 USA
| | - Karl H G Schulz
- Department of Chemistry, Carnegie Mellon University 4400 Fifth Avenue Pittsburgh Pennsylvania 15213 USA
| | - Roberto R Gil
- Department of Chemistry, Carnegie Mellon University 4400 Fifth Avenue Pittsburgh Pennsylvania 15213 USA
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44
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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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45
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Buevich AV, Elyashberg ME. Enhancing computer-assisted structure elucidation with DFT analysis of J-couplings. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2020; 58:594-606. [PMID: 31916609 DOI: 10.1002/mrc.4996] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 01/06/2020] [Accepted: 01/07/2020] [Indexed: 06/10/2023]
Abstract
Computer-assisted structure elucidation (CASE) is the class of expert systems that derives molecular structures primarily from one-dimensional and two-dimensional nuclear magnetic resonance data. Contemporary CASE systems, including Advanced Chemistry Development/Structure Elucidator (ACD/SE), consider cross-peaks in heteronuclear multiple bond coherence (HMBC) and correlation spectroscopy (COSY) spectra as two- or three-bond correlations by default. However, four and more bond correlations (nonstandard correlations [NSCs]) could be present in these spectra too. The indiscriminate addition of NSCs to the CASE computations is prohibitively expensive. To address this problem, the ACD/SE program performs a logical analysis of observed correlations and determines the minimum number of NSCs. Guided by this information, a more efficient fuzzy structure generation (FSG) algorithm is subsequently applied. Until now, the FSG algorithm was utilized without any verification of the reliability of found NSCs. Here, we report a verification method for NSCs based on the relationship between NSCs and J-couplings computed with high accuracy density functional theory (DFT) methods. We used the example of strychnine to show that 41 (32%) of 8-Hz HMBC cross-peaks were NSCs and were consistent with 4-6 JCH couplings greater than 0.3 Hz. This cutoff value was largely confirmed by the analysis of NSCs in 11 real-world natural products elucidated by ACD/SE. Additionally, utilizing the example of the CASE study of cleospinol A, we showed that the DFT-computed J-couplings of NSCs can distinctively differentiate the correct structure among six proposed isomers. The proposed approach of NSC verification should further improve the robustness of CASE analysis and can help reveal potential problems with reported experimental data.
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Affiliation(s)
- Alexei V Buevich
- Department of Discovery and Preclinical Sciences, Process Research and Development, NMR Structure Elucidation, Merck & Co., Inc, Kenilworth, NJ
| | - Mikhail E Elyashberg
- Moscow Department, Advanced Chemistry Development (ACD/Laboratories), Moscow, Russia
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46
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Marcarino MO, Zanardi MM, Sarotti AM. The Risks of Automation: A Study on DFT Energy Miscalculations and Its Consequences in NMR-based Structural Elucidation. Org Lett 2020; 22:3561-3565. [DOI: 10.1021/acs.orglett.0c01001] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Maribel O. Marcarino
- Instituto de Quı́mica Rosario (IQUIR, CONICET-UNR) and Facultad de Ciencias Bioquı́micas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, S2002LRK Rosario, República Argentina
| | - María M. Zanardi
- Facultad de Quı́mica e Ingenierı́a del Rosario, Pontificia Universidad Católica Argentina, Av. Pellegrini 3314, S2002QEO Rosario, Argentina
| | - Ariel M. Sarotti
- Instituto de Quı́mica Rosario (IQUIR, CONICET-UNR) and Facultad de Ciencias Bioquı́micas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, S2002LRK Rosario, República Argentina
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47
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Koos MRM, Navarro‐Vázquez A, Anklin C, Gil RR. Computer‐Assisted 3D Structure Elucidation (CASE‐3D): The Structural Value of
2
J
CH
in Addition to
3
J
CH
Coupling Constants. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201915103] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Martin R. M. Koos
- Department of Chemistry Carnegie Mellon University Pittsburgh PA USA
| | | | | | - Roberto R. Gil
- Department of Chemistry Carnegie Mellon University Pittsburgh PA USA
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48
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Li XL, Chi LP, Navarro-Vázquez A, Hwang S, Schmieder P, Li XM, Li X, Yang SQ, Lei X, Wang BG, Sun H. Stereochemical Elucidation of Natural Products from Residual Chemical Shift Anisotropies in a Liquid Crystalline Phase. J Am Chem Soc 2020; 142:2301-2309. [PMID: 31889437 DOI: 10.1021/jacs.9b10961] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Determination of the stereochemistry of organic molecules still represents one of the major obstacles in the structure elucidation procedure in drug discovery. Although the application of residual dipolar couplings (RDCs) has revolutionized this field, residual chemical shift anisotropies (RCSAs) which contain valuable structural information for nonprotonated carbons have only been scarcely employed so far. In this study, we present a simple but highly effective solution to extract RCSAs of the analytes in a liquid crystalline phase formed by AAKLVFF oligopeptides. This method does not require any special instruments, devices, or correction during postacquisition data analysis and thus can be easily applied in any chemistry laboratory. To illustrate the potential of this method, the relative configurations of four known natural products (1-4) belonging to different structural classes were confirmed. Moreover, we unambiguously elucidated the stereochemistry of spiroepicoccin A (5), a rare thiodiketopiperazine marine natural product whose configuration could not be assigned based on conventional NMR methods.
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Affiliation(s)
- Xiao-Lu Li
- Section of Structural Biology , Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) , Berlin 13125 , Germany
| | - Lu-Ping Chi
- Laboratory of Marine Biology and Biotechnology , Qingdao National Laboratory for Marine Science and Technology , Qingdao 266071 , People's Republic of China.,University of Chinese Academy of Sciences , Yuquan Road 19A , Beijing 100049 , People's Republic of China
| | - Armando Navarro-Vázquez
- Departamento de Química Fundamental , Universidade Federal de Pernambuco , Recife , Pernambuco 50670-901 , Brazil
| | - Songhwan Hwang
- Section of Structural Biology , Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) , Berlin 13125 , Germany
| | - Peter Schmieder
- Section of Structural Biology , Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) , Berlin 13125 , Germany
| | - Xiao-Ming Li
- Laboratory of Marine Biology and Biotechnology , Qingdao National Laboratory for Marine Science and Technology , Qingdao 266071 , People's Republic of China
| | - Xin Li
- Laboratory of Marine Biology and Biotechnology , Qingdao National Laboratory for Marine Science and Technology , Qingdao 266071 , People's Republic of China
| | - Sui-Qun Yang
- Laboratory of Marine Biology and Biotechnology , Qingdao National Laboratory for Marine Science and Technology , Qingdao 266071 , People's Republic of China
| | - Xinxiang Lei
- School of Pharmaceutical Sciences , South Central University for Nationalities , Wuhan 430074 , People's Republic of China
| | - Bin-Gui Wang
- Laboratory of Marine Biology and Biotechnology , Qingdao National Laboratory for Marine Science and Technology , Qingdao 266071 , People's Republic of China
| | - Han Sun
- Section of Structural Biology , Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) , Berlin 13125 , Germany
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49
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Navarro-Vázquez A. When not to rely on Boltzmann populations. Automated CASE-3D structure elucidation of hyacinthacines through chemical shift differences. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2020; 58:139-144. [PMID: 31663628 DOI: 10.1002/mrc.4951] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 09/03/2019] [Accepted: 10/09/2019] [Indexed: 06/10/2023]
Abstract
An Akaike Information Criterion (AIC) procedure (CASE-3D) has been successfully applied to the NMR based configurational assignment of reported hyacinthacines (1-3,5-8), recently target of configurational analysis using the popular DP4+ methodology. The present analysis makes use of reported 1 H and 13 C shifts and, in some particular cases, a few 3 JHH couplings. The difficulty in proper computational prediction of relative energies, in molecules capable of inter-molecular hydrogen bonding, introduces large errors in the prediction of conformationally averaged NMR properties in methods based on Boltzmann averaging such as DP4 or DP4+. In contrast CASE-3D conformational amplitudes are free parameters in the model. Here we show that the CASE-3D conformational model selection strategy, when combined with a larger energy cutoff in the molecular-modelling conformational exploration, was sufficient to correctly assign the relative configuration in five of seven cases. Introduction of more information, either by supplementing 1 H and 13 C data with a few J-couplings, or using a cutoff based on computed DFT energies for the definition of the conformational ensembles, allowed the safe assignment of configuration for all compounds.
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Affiliation(s)
- Armando Navarro-Vázquez
- Universidade Federal de Pernambuco, Departamento de Química Fundamental, CCEN, Recife, Pernambuco, Brazil, 50670-90.1
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50
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Koos MRM, Navarro‐Vázquez A, Anklin C, Gil RR. Computer‐Assisted 3D Structure Elucidation (CASE‐3D): The Structural Value of
2
J
CH
in Addition to
3
J
CH
Coupling Constants. Angew Chem Int Ed Engl 2020; 59:3938-3941. [DOI: 10.1002/anie.201915103] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Indexed: 02/04/2023]
Affiliation(s)
- Martin R. M. Koos
- Department of Chemistry Carnegie Mellon University Pittsburgh PA USA
| | | | | | - Roberto R. Gil
- Department of Chemistry Carnegie Mellon University Pittsburgh PA USA
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