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Vermeyen T, Batista ANL, Valverde AL, Herrebout W, Batista JM. Pushing the boundaries of VCD spectroscopy in natural product chemistry. Phys Chem Chem Phys 2023; 25:13825-13832. [PMID: 37191271 DOI: 10.1039/d3cp00886j] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Vibrational circular dichroism (VCD) is one of the most powerful techniques to assess the stereochemistry of chiral molecules in solution state. The need for quantum chemical calculations to interpret experimental data, however, has precluded its widespread use by non-experts. Herein, we propose the search and validation of IR and VCD spectral markers to circumvent the requirement of DFT calculations allowing for absolute configuration assignments even in complex mixtures. To that end, a combination of visual inspection and machine learning based methods is used. Monoterpene mixtures are selected for this proof-of-concept study.
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Affiliation(s)
- Tom Vermeyen
- Department of Chemistry, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp, Belgium.
- Department of Chemistry, Ghent University, Krijgslaan 281, B-9000 Ghent, Belgium
| | - Andrea N L Batista
- Institute of Chemistry, Fluminense Federal University, Outeiro de São João Batista s/n, 24020-141 Niterói-RJ, Brazil
| | - Alessandra L Valverde
- Institute of Chemistry, Fluminense Federal University, Outeiro de São João Batista s/n, 24020-141 Niterói-RJ, Brazil
| | - Wouter Herrebout
- Department of Chemistry, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp, Belgium.
| | - João M Batista
- Federal University of São Paulo, Institute of Science and Technology, R. Talim 330, 12231-280, São José dos Campos-SP, Brazil.
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2
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Plakilactone J: structure and absolute configuration. Tetrahedron Lett 2022. [DOI: 10.1016/j.tetlet.2022.154241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Dos Santos FM, da Silva Mota GV, Martorano LH, de Albuquerque ACF, da Silva CA, da Silva AM, de Jesus Chaves Neto AM, Valverde AL, Cardoso EF, Costa FLP. Combined application of DP4+ and ANN-PRA to determine the relative configuration of natural products: The alpha-bisabol case study. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2022; 60:533-540. [PMID: 35229358 DOI: 10.1002/mrc.5261] [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: 01/24/2022] [Revised: 02/22/2022] [Accepted: 02/24/2022] [Indexed: 06/14/2023]
Abstract
The combination of computational methods and experimental data from Nuclear Magnetic Resonance (NMR) is a considerably valuable tool in the elucidation of new natural product structures and, also, in the structural revision of previously reported compounds. Until recently, only classical statistical parameters were used, for example, linear correlation coefficient (R2 ), mean absolute error (MAE), or root mean square deviation (RMSD), as a way to statistically "validate" the structure pointed out by experimental NMR spectra. Regarding the resolution of the relative configuration of organic molecules, novel tools were available in the last few years to assist in the NMR elucidation process. The most relevant are DP4+, which is based on a Bayesian probability, and ANN-PRA, which is based on artificial neural networks. The combined application of these tools has become the most accurate and important alternative to solve structural and stereochemical problems in natural product chemistry. Therefore, herein, in this case study, we intended to promote these novel tools, exploring the strengths and limitations of each approach in resolving the relative configuration of the sesquiterpene alpha-bisabol. We also highlighted the advantages of the complementary use of H- and C-DP4+ to obtain optimal results in the differentiation of the stereoisomers, validating the proposal with ANN-PRA method.
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Martorano LH, Brito JT, de Albuquerque ACF, Ribeiro CMR, Fiorot RG, Carneiro JWDM, Costa FLP, Valverde AL, Dos Santos Junior FM. Revisiting the structure of Heliannuol L: A computational approach. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2022; 60:434-441. [PMID: 34741339 DOI: 10.1002/mrc.5230] [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: 09/29/2021] [Revised: 10/30/2021] [Accepted: 11/01/2021] [Indexed: 06/13/2023]
Abstract
Recently, structural elucidation of natural products has undergone a revolution. The combined use of different modern spectroscopic methods has allowed obtaining a complete structural assignment of natural products using small amounts of sample. However, despite the extraordinary ongoing advances in spectroscopy, the mischaracterization of natural products has been and remains a recurrent problem, especially when the substance presents several stereogenic centers. The misinterpretation of nuclear magnetic resonance (NMR) data has resulted in frequent reports addressing structural reassignment. In this context, a great effort has been devoted to developing quantum chemical calculations that simulate NMR parameters accurately, allowing to achieve a more precise spectral interpretation. In this work, we employed a protocol for theoretical calculations of 1 H NMR chemical shifts and coupling constants using density functional theory (DFT), followed by the application of the DP4+ method to revisit the structure of Heliannuol L, a member of the Heliannuol class, isolated from Helianthus annuus. Our results indicate that the originally proposed structure of Heliannuol L needs a stereochemical reassignment, placing the hydroxyl bonded to C10 in the opposite side of the methyl and hydroxyl groups bonded to C7 and C8, respectively.
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Affiliation(s)
- Lucas H Martorano
- Department of Organic Chemistry, Chemistry Institute, Fluminense Federal University (UFF), Niterói, Brazil
| | - Jordana T Brito
- Department of Organic Chemistry, Chemistry Institute, Fluminense Federal University (UFF), Niterói, Brazil
| | | | - Carlos Magno Rocha Ribeiro
- Department of Organic Chemistry, Chemistry Institute, Fluminense Federal University (UFF), Niterói, Brazil
| | - Rodolfo Goetze Fiorot
- Department of Organic Chemistry, Chemistry Institute, Fluminense Federal University (UFF), Niterói, Brazil
| | | | | | - Alessandra L Valverde
- Department of Organic Chemistry, Chemistry Institute, Fluminense Federal University (UFF), Niterói, Brazil
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5
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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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Costa FLP, de Albuquerque ACF, Fiorot RG, Lião LM, Martorano LH, Mota GVS, Valverde AL, Carneiro JWM, dos Santos Junior FM. Structural characterisation of natural products by means of quantum chemical calculations of NMR parameters: new insights. Org Chem Front 2021. [DOI: 10.1039/d1qo00034a] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
In this review, we focus in all aspects of NMR simulation of natural products, from the fundamentals to the new computational toolboxes available, combining advanced quantum chemical calculations with upstream data processing and machine learning.
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Affiliation(s)
| | - Ana C. F. de Albuquerque
- Departamento de Química Orgânica
- Instituto de Química
- Universidade Federal Fluminense
- Niterói-RJ
- Brazil
| | - Rodolfo G. Fiorot
- Departamento de Química Orgânica
- Instituto de Química
- Universidade Federal Fluminense
- Niterói-RJ
- Brazil
| | - Luciano M. Lião
- Instituto de Química
- Universidade Federal de Goiás
- 74690-900 Goiânia-GO
- Brazil
| | - Lucas H. Martorano
- Departamento de Química Orgânica
- Instituto de Química
- Universidade Federal Fluminense
- Niterói-RJ
- Brazil
| | - Gunar V. S. Mota
- Faculdade de Ciências Naturais/Instituto de Ciências Exatas e Naturais
- Universidade Federal do Pará
- Belém-PA
- Brazil
| | - Alessandra L. Valverde
- Departamento de Química Orgânica
- Instituto de Química
- Universidade Federal Fluminense
- Niterói-RJ
- Brazil
| | - José W. M. Carneiro
- Departamento de Química Inorgânica
- Instituto de Química
- Universidade Federal Fluminense
- Niterói-RJ
- Brazil
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Carroll AR, Copp BR, Davis RA, Keyzers RA, Prinsep MR. Marine natural products. Nat Prod Rep 2021; 38:362-413. [PMID: 33570537 DOI: 10.1039/d0np00089b] [Citation(s) in RCA: 198] [Impact Index Per Article: 66.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
This review covers the literature published in 2019 for marine natural products (MNPs), with 719 citations (701 for the period January to December 2019) referring to compounds isolated from marine microorganisms and phytoplankton, green, brown and red algae, sponges, cnidarians, bryozoans, molluscs, tunicates, echinoderms, mangroves and other intertidal plants and microorganisms. The emphasis is on new compounds (1490 in 440 papers for 2019), together with the relevant biological activities, source organisms and country of origin. Pertinent reviews, biosynthetic studies, first syntheses, and syntheses that led to the revision of structures or stereochemistries, have been included. Methods used to study marine fungi and their chemical diversity have also been discussed.
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Affiliation(s)
- Anthony R Carroll
- School of Environment and Science, Griffith University, Gold Coast, Australia. and Griffith Institute for Drug Discovery, Griffith University, Brisbane, Australia
| | - Brent R Copp
- School of Chemical Sciences, University of Auckland, Auckland, New Zealand
| | - Rohan A Davis
- Griffith Institute for Drug Discovery, Griffith University, Brisbane, Australia and School of Enivironment and Science, Griffith University, Brisbane, Australia
| | - Robert A Keyzers
- Centre for Biodiscovery, School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington, New Zealand
| | - Michèle R Prinsep
- Chemistry, School of Science, University of Waikato, Hamilton, New Zealand
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