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Martins LMOS, Souto FT, Hoye TR, Alvarenga ES. Deciphering molecular structures: NMR spectroscopy and quantum mechanical insights of halogenated 4H-Chromenediones. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2024; 62:583-598. [PMID: 38557999 DOI: 10.1002/mrc.5445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 02/15/2024] [Accepted: 03/13/2024] [Indexed: 04/04/2024]
Abstract
Sesquiterpene lactones (SL) represent a class of secondary metabolites found in the Asteraceae family, notable for their unique structures. The SL α-santonin (1) and its derivatives are worthy of mention due to their diverse biological properties. Additionally, 4H-chromenes and 4H-chromones are appealing frameworks holding the capability to be used as structural motifs for new drugs. Furthermore, unambiguous structural elucidation is crucial for developing novel compounds for diverse applications. In this context, it is common to find in the literature molecules erroneously assigned. Therefore, the use of quantum mechanical calculations to simulate NMR chemical shifts has emerged as a valuable strategy. In this work, we conceived the synthesis of two halogenated 4H-chromenediones derived from photosantonic acid (2), a photoproduct arising from irradiation of α-santonin (1) in the ultraviolet region. The structure of the chlorinated and brominated products was determined by NMR analysis, with the aid of quantum mechanical calculations at the B3LYP/6-311 + G(2d,p)//M062x/6-31 + G(d,p) level of theory. All analyses were in agreement and led to the assignment of the brominated 4H-chromene-2,7-dione as (3S,3aS,5aR,9bS)-5a-(2-bromopropan-2-yl)-3-methyl-3,3a,5,5a,8,9b-hexahydro-4H-furo[2,3-f]chromene-2,7-dione (11b) and of the chlorinated 4H-chromene-2,7-dione as (3S,3aS,5aR,9bS)-5a-(2-chloropropan-2-yl)-3-methyl-3,3a,5,5a,8,9b-hexahydro-4H-furo[2,3-f]chromene-2,7-dione (12b). The diastereoselectivities of the reactions were explained based on products and intermediates formation energy calculated using B3LYP/6-31 + G(d,p) as the level of theory. Structures 11b and 12b were identified as the thermodynamic and kinetic products of the reaction among all candidates. Consequently, the strategy utilized in this study is robust and successfully illustrates the use of quantum mechanical calculations in the structural elucidation of new compounds with potential applications as novel drugs or products.
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Affiliation(s)
- Lucas M O S Martins
- Department of Chemistry, Universidade Federal de Viçosa, Viçosa, MG, Brazil
- Chemistry Institute, Universidade de São Paulo, São Paulo, SP, Brazil
| | | | - Thomas R Hoye
- Department of Chemistry, University of Minnesota, Minneapolis, MN, USA
| | - Elson S Alvarenga
- Department of Chemistry, Universidade Federal de Viçosa, Viçosa, MG, Brazil
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2
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Identifying the meta, para and ortho isomers in octa(aminophenyl)silsesquioxane (OAPS) from joint experimental characterizations and theoretical predictions of the IR and NMR spectra. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2022.133510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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3
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Krivdin LB. Computational 1 H and 13 C NMR in structural and stereochemical studies. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2022; 60:733-828. [PMID: 35182410 DOI: 10.1002/mrc.5260] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 02/14/2022] [Accepted: 02/16/2022] [Indexed: 06/14/2023]
Abstract
Present review outlines the advances and perspectives of computational 1 H and 13 C NMR applied to the stereochemical studies of inorganic, organic, and bioorganic compounds, involving in particular natural products, carbohydrates, and carbonium ions. The first part of the review briefly outlines theoretical background of the modern computational methods applied to the calculation of chemical shifts and spin-spin coupling constants at the DFT and the non-empirical levels. The second part of the review deals with the achievements of the computational 1 H and 13 C NMR in the stereochemical investigation of a variety of inorganic, organic, and bioorganic compounds, providing in an abridged form the material partly discussed by the author in a series of parent reviews. Major attention is focused herewith on the publications of the recent years, which were not reviewed elsewhere.
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Affiliation(s)
- Leonid B Krivdin
- A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, Irkutsk, Russia
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4
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Pinto BN, Moura GA, Demuner AJ, Alvarenga ES. Structural elucidation of a novel pyrrolizidine alkaloid isolated from Crotalaria retusa L. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2022.132394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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5
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Martins LMOS, Santos JO, Hoye T, Alvarenga ES. Synthesis of a novel naphthalenone endoperoxide and structural elucidation by nuclear magnetic resonance spectroscopy and theoretical calculation. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2022; 60:139-147. [PMID: 34265119 DOI: 10.1002/mrc.5195] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 06/11/2021] [Accepted: 07/13/2021] [Indexed: 06/13/2023]
Abstract
Sesquiterpene lactones are found in plants of Asteraceae family, and endoperoxides are known for their antimalarial activity. Structural elucidation is a relevant aspect; however, it is not uncommon to find incorrect or incomplete structural assignments in the literature. Calculations based in quantum mechanics are frequently used to compute 1 H and 13 C NMR chemical shifts, and after comparing with the experimental data, the correct structure is established from diverse candidates. Targeting the synthesis of bioactive compounds, we envisaged the synthesis of a novel endoperoxide from the natural sesquiterpene lactone α-santonin (2). Photochemical transformation of α-santonin (2) to mazdasantonin (4) followed by photooxidation catalyzed by rose bengal afforded the novel endoperoxide 5. This new endoperoxide contains five stereogenic centers and is analogous to the antimalarial agent artemisinin (1). The relative configuration of the stereogenic centers of the endoperoxide were established by nuclear magnetic resonance (NMR) analyses and confirmed by theoretical calculations. All approaches were in complete agreement, and the structure of mazdasantonin endoperoxide was established as (3S,3aS,5aS,8R,9bS)-3,6,6-trimethyl-3,3a,4,5,8,9b-hexahydro-2H-5a,8-epidioxynaphtho[1,2-b]furan-2,7(6H)-dione.
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Affiliation(s)
| | - Juliana O Santos
- Department of Chemistry, Universidade Federal de Viçosa, Viçosa, Brazil
| | - Thomas Hoye
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota, USA
| | - Elson S Alvarenga
- Department of Chemistry, Universidade Federal de Viçosa, Viçosa, Brazil
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6
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Semenov VA, Krivdin LB. Computational NMR of natural products. RUSSIAN CHEMICAL REVIEWS 2022. [DOI: 10.1070/rcr5027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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7
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Semenov VA, Krivdin LB. Computational 1 H and 13 C NMR of the trimeric monoterpenoid indole alkaloid strychnohexamine: Selected spectral updates. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2021; 59:691-700. [PMID: 33386651 DOI: 10.1002/mrc.5129] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 12/26/2020] [Accepted: 12/28/2020] [Indexed: 06/12/2023]
Abstract
Very large trimeric indole alkaloid strychnohexamine, with empirical formula C59 H60 N6 O (66 second-row atoms and 60 protons), has been subjected to the state-of-the-art computation of the 1 H and 13 C nuclear magnetic resonance (NMR) chemical shifts of its configurational isomers at each of the 14 asymmetric centers. Several spectral reassignments and corrections of 1 H and 13 C NMR spectra of this alkaloid were suggested based on the PBE0/pcSseg-2//pcseg-2 calculation of its NMR chemical shifts. Thus, all pairs of diastereotopic protons were assigned together with four aromatic carbon resonances of C-9 and C-11, C-9″, and C-11″. In addition, the unassigned chemical shifts of carbon C-23″ and proton at C-3' in, accordingly, 13 C and 1 H NMR spectra were predicted.
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Affiliation(s)
- Valentin A Semenov
- A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, Irkutsk, Russia
| | - Leonid B Krivdin
- A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, Irkutsk, Russia
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Torrent KBA, Alvarenga ES. Synthesis and Identification of Epoxy Derivatives of 5-Methylhexahydroisoindole-1,3-dione and Biological Evaluation. Molecules 2021; 26:1923. [PMID: 33808049 PMCID: PMC8037305 DOI: 10.3390/molecules26071923] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Revised: 03/24/2021] [Accepted: 03/25/2021] [Indexed: 01/25/2023] Open
Abstract
Cyclic imides belong to a well-known class of organic compounds with various biological activities, promoting a great interest in compounds with this functional group. Due to the structural complexity of some molecules and their spectra, it is necessary to use several spectrometric methods associated with auxiliary tools, such as the theoretical calculation for the structural elucidation of complex structures. In this work, the synthesis of epoxy derivatives of 5-methylhexahydroisoindole-1,3-diones was carried out in five steps. Diels-Alder reaction of isoprene and maleic anhydride followed by reaction with m-anisidine afforded the amide (2). Esterification of amide (2) with methanol in the presence of sulfuric acid provided the ester (3) that cyclized in situ to give imides 4 and 4-ent. Epoxidation of 4 and 4-ent with meta-chloroperbenzoic acid (MCPBA) afforded 5a and 5b. The diastereomers were separated by silica gel flash column chromatography, and their structures were determined by analyses of the spectrometric methods. Their structures were confirmed by matching the calculated 1H and 13C NMR chemical shifts of (5a and 5b) with the experimental data of the diastereomers using MAE, CP3, and DP4 statistical analyses. Biological assays were carried out to evaluate the potential herbicide activity of the imides. Compounds 5a and 5b inhibited root growth of the weed Bidens pilosa by more than 70% at all the concentrations evaluated.
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Affiliation(s)
| | - Elson S. Alvarenga
- Department of Chemistry, Universidade Federal de Viçosa, Viçosa, MG 36570-900, Brazil;
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9
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Lopes DT, Hoye TR, Alvarenga ES. Characterization of stereoisomeric 5-(2-nitro-1-phenylethyl)furan-2(5H)-ones by computation of 1 H and 13 C NMR chemical shifts and electronic circular dichroism spectra. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2021; 59:43-51. [PMID: 32621355 PMCID: PMC7985851 DOI: 10.1002/mrc.5073] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 06/28/2020] [Accepted: 06/29/2020] [Indexed: 06/11/2023]
Abstract
In the present work, we describe the preparation of two diastereomers from the enantioselective Michael addition of furan-2(5H)-one to (E)-(2-nitrovinyl)benzene catalyzed by a dinuclear Zn-complex. The relative configurations of the diastereomeric products were assigned by comparing nuclear magnetic resonance (NMR) experimental chemical shift data with those computed by density functional theory (DFT) methods. Corrected mean absolute error (CMAE) and CP3 analyses were used to compare the data sets. The absolute configuration of each diastereomer was initially assigned by analysis of electronic circular dichroism (ECD) data, which was consistent with that of the known X-ray crystallographic structure of the product of a related reaction, namely, (R)-5-((R)-1-(4-chlorophenyl)-2-nitroethyl)furan-2(5H)-one.
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Affiliation(s)
- Dayane T. Lopes
- Department of Chemistry, Universidade Federal de Viçosa, Viçosa, MG 36571-900, Brazil
| | - Thomas R. Hoye
- Department of Chemistry, University of Minnesota, Minneapolis, MN 55455, USA
| | - Elson S. Alvarenga
- Department of Chemistry, Universidade Federal de Viçosa, Viçosa, MG 36571-900, Brazil
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10
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Hernández Mancera JP, Núñez-Zarur F, Gutiérrez-Oliva S, Toro-Labbé A, Vivas-Reyes R. Diels-Alder reaction mechanisms of substituted chiral anthracene: A theoretical study based on the reaction force and reaction electronic flux. J Comput Chem 2020; 41:2022-2032. [PMID: 32585758 DOI: 10.1002/jcc.26360] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 02/02/2020] [Indexed: 11/08/2022]
Abstract
Quantum chemical calculations were used to study the mechanism of Diels-Alder reactions involving chiral anthracenes as dienes and a series of dienophiles. The reaction force analysis was employed to obtain a detailed scrutiny of the reaction mechanisms, it has been found that thermodynamics and kinetics of the reactions are quite consistent: the lower the activation energy, the lower the reaction energy, thus following the Bell-Evans-Polanyi principle. It has been found that activation energies are mostly due to structural rearrangements that in most cases represented more than 70% of the activation energy. Electronic activity mostly due to changes in σ and π bonding were revealed by the reaction electronic flux (REF), this property helps identify whether changes on σ or π bonding drive the reaction. Additionally, new global indexes describing the behavior of the electronic activity were introduced and then used to classify the reactions in terms of the spontaneity of their electronic activity. Local natural bond order electronic population analysis was used to check consistency with global REF through the characterization of specific changes in the electronic density that might be responsible for the activity already detected by the REF. Results show that reactions involving acetoxy lactones are driven by spontaneous electronic activity coming from bond forming/strengthening processes; in the case of maleic anhydrides and maleimides it appears that both spontaneous and non-spontaneous electronic activity are quite active in driving the reactions.
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Affiliation(s)
| | | | - Soledad Gutiérrez-Oliva
- Laboratorio de Química Teórica Computacional (QTC), Facultad de Química y de Farmacia, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Alejandro Toro-Labbé
- Laboratorio de Química Teórica Computacional (QTC), Facultad de Química y de Farmacia, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Ricardo Vivas-Reyes
- Grupo de Química Cuántica y Teórica, Facultad de Ciencias Exactas y Naturales, Universidad de Cartagena, Cartagena, Colombia.,Grupo CipTec, Fundación Universitaria Tecnológico de Comfenalco, Facultad de Ingenierías, Programa de Ingeniería Industrial, Cartagena de Indias, Bolivar, Colombia
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11
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Hernández‐Mancera JP, Núñez‐Zarur F, Vivas‐Reyes R. Diels-Alder Reactivity of a Chiral Anthracene Template with Symmetrical and Unsymmetrical Dienophiles: A DFT Study. ChemistryOpen 2020; 9:748-761. [PMID: 32670739 PMCID: PMC7349856 DOI: 10.1002/open.202000137] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 05/29/2020] [Indexed: 11/12/2022] Open
Abstract
In this work, we used Density Functional Theory calculations to assess the factors that control the reactivity of a chiral anthracene template with three sets of dienophiles including maleic anhydrides, maleimides and acetoxy lactones in the context of Diels-Alder cycloadditions. The results obtained here (at the M06-2X/6-311++G(d,p) level of theory) suggest that the activation energies for maleic anhydrides and acetoxy lactones are dependent on the nature of the substituent in the dienophile. Among all studied substituents, only -CN reduces the energy barrier of the cycloaddition. For maleimides, the activation energies are independent of the heteroatom of the dienophile and the R group attached to it. The analysis of frontier molecular orbitals, charge transfer and the activation strain model (at the M06-2X/TZVP level based on M06-2X/6-311++G(d,p) geometries) suggest that the activation energies in maleic anhydrides are mainly controlled by the amount of charge transfer from the diene to the dienophile during cycloaddition. For maleimides, there is a dual control of interaction and strain energies on the activation energies, whereas for the acetoxy lactones the activation energies seem to be controlled by the degree of template distortion at the transition state. Finally, calculations show that considering a catalyst on the studied cycloadditions changes the reaction mechanism from concerted to stepwise and proceed with much lower activation energies.
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Affiliation(s)
- Jennifer P. Hernández‐Mancera
- Grupo de Química Cuántica y TeóricaFacultad de Ciencias Exactas y NaturalesUniversidad de CartagenaCampus San PabloCartagena130015Colombia
| | - Francisco Núñez‐Zarur
- Facultad de Ciencias BásicasUniversidad de MedellínCarrera 87 N° 30–65050026MedellínColombia) E-Mil
| | - Ricardo Vivas‐Reyes
- Grupo de Química Cuántica y TeóricaFacultad de Ciencias Exactas y NaturalesUniversidad de CartagenaCampus San PabloCartagena130015Colombia
- Grupo CipTecFundación UniversitariaTecnológico de ComfenalcoFacultad de Ingenierías Cartagena de IndiasBolívar130001Colombia
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12
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Pinto BNS, Teixeira MG, Alvarenga ES. Synthesis and structural elucidation of a phthalide analog using NMR analysis and DFT calculations. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2020; 58:559-565. [PMID: 31774576 DOI: 10.1002/mrc.4976] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 11/18/2019] [Accepted: 11/22/2019] [Indexed: 06/10/2023]
Abstract
Phtalides are secondary metabolites found in several fungi with a wide range of biological activities. A novel phthalide analog was synthesized by Diels-Alder reaction between cyclopentadiene and 3,4-dichlorofuran-2(5H)-one. Quantum mechanical calculations were used in conjunction with the spectrometric methods to determine the structure of the title compound. The calculated NMR chemical shifts for eight candidate pairs of enantiomers were compared with the experimental NMR chemical shifts applying the DP4 probability and mean absolute errors methodology. DP4 analysis using 1 H and 13 C NMR chemical shifts without assignment of the signals presented 100% probability for the correct candidate structure 3d, proving the consistency of the method even without spectra interpretation. Results from theoretical calculation and NMR spectra interpretation were in agreement to the structure of rac-(3aR,4S,4aS,5R,8S,8aR,9R,9aS)-3a,9a-dichloro-3a,4,4a,5,8,8a,9,9a-octahydro-4,9:5,8-dimethanonaphtho[2,3-c]furan-1(3H)-one.
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Affiliation(s)
- Bryan N S Pinto
- Department of Chemistry, Universidade Federal de Viçosa, Viçosa, Brazil
| | - Milena G Teixeira
- Department of Chemistry, Universidade Federal de Viçosa, Viçosa, Brazil
| | - Elson S Alvarenga
- Department of Chemistry, Universidade Federal de Viçosa, Viçosa, Brazil
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13
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Krivdin LB. Computational 1 H NMR: Part 3. Biochemical studies. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2020; 58:15-30. [PMID: 31286566 DOI: 10.1002/mrc.4895] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 05/14/2019] [Accepted: 05/18/2019] [Indexed: 06/09/2023]
Abstract
This is the third and the last part of three closely interrelated reviews dealing with computation of 1 H nuclear magnetic resonance chemical shifts and 1 H-1 H spin-spin coupling constants. Present review deals with the computation of these parameters in biologically active natural products, carbohydrates, and other molecules of biological origin focusing on stereochemical applications of computational 1 H nuclear magnetic resonance to these objects.
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Affiliation(s)
- Leonid B Krivdin
- A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, Irkutsk, Russia
- Department of Chemistry, Angarsk State Technical University, Angarsk, Russia
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Teixeira MG, Alvarenga ES, Lopes DT, Oliveira DF. Herbicidal activity of isobenzofuranones and in silico identification of their enzyme target. PEST MANAGEMENT SCIENCE 2019; 75:3331-3339. [PMID: 31026360 DOI: 10.1002/ps.5456] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2019] [Revised: 03/23/2019] [Accepted: 04/26/2019] [Indexed: 06/09/2023]
Abstract
BACKGROUND Given the weed resistance to various herbicides with different mechanisms of action, the search for new compounds that are more effective and exhibit low levels of impact to other species in nature has been imperative in the field of the agriculture. For this purpose, 16 phthalides, and furan-2(5H)-one were synthetized and evaluated for their effectiveness as herbicides in seeds of Sorghum bicolor (sorghum), Cucumis sativus (cucumber), and Allium cepa (onion). Furthermore, a preliminary in silico study was carried out to identify the enzyme target of the most active compounds. RESULTS In the assays with S. bicolor, the mixture rac-(3aR,4R,5S,6S,7S,7aS)-5,6-dibromohexahydro-4,7-methanoisobenzofuran-1(3H)-one + rac-(3aR,4R,5R,6R,7S,7aS)-5,6-dibromohexahydro-4,7-methanoisobenzofuran-1(3H)-one (15a + 15b) showed comparable inhibitory activity to (S)-metolachlor, which was used as control herbicide at concentrations ranging from 50 μm to 1000 μm. The developments of the seeds evaluated were altered by all 17 compounds, either stimulating or inhibiting. The best results were presented by compounds 15a, and 15b, either in their pure form or as a mixture. CONCLUSION The results presented by 15a, and 15b were superior to the activity of the commercial herbicide (S)-metolachlor in the assays with C. sativus, and A. cepa. The in silico study provides strong evidence that the most active compounds bind to strigolactones esterases D14 through the same binding site of (5R)-5-hydroxy-3-methylfuran-2(5H)-one (H3M), which is one of the strigolactones (SLs) cleavage products. © 2019 Society of Chemical Industry.
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Affiliation(s)
- Milena G Teixeira
- Departament of Chemistry, Universidade Federal de Viçosa, Viçosa, Brazil
| | - Elson S Alvarenga
- Departament of Chemistry, Universidade Federal de Viçosa, Viçosa, Brazil
| | - Dayane T Lopes
- Departament of Chemistry, Universidade Federal de Viçosa, Viçosa, Brazil
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Krivdin LB. Computational protocols for calculating 13C NMR chemical shifts. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2019; 112-113:103-156. [PMID: 31481156 DOI: 10.1016/j.pnmrs.2019.05.004] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2019] [Revised: 05/19/2019] [Accepted: 05/20/2019] [Indexed: 06/10/2023]
Abstract
The most recent results dealing with the computation of 13C NMR chemical shifts in chemistry (small molecules, saturated, unsaturated and aromatic compounds, heterocycles, functional derivatives, coordination complexes, carbocations, and natural products) are reviewed, paying special attention to theoretical background and accuracy, the latter involving solvent effects, vibrational corrections, and relativistic effects.
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Affiliation(s)
- Leonid B Krivdin
- A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, Favorsky St. 1, 664033 Irkutsk, Russia.
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Alvarenga ES, Teixeira MG, Lopes DT, Demuner AJ. Computation and structural elucidation of compounds formed via epoxide alcoholysis. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2019; 57:S101-S107. [PMID: 30577073 DOI: 10.1002/mrc.4818] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 12/11/2018] [Accepted: 12/13/2018] [Indexed: 06/09/2023]
Abstract
Isobenzofuranones are known for their wide range of biological activities such as fungicide, insecticide, and anticancer. The search for novel bioactive compounds was performed by reaction of epoxide 2 with methanol, ethanol, propan-1-ol, propan-2-ol, and butan-1-ol. The mechanism for the stereoselective and stereospecific epoxide opening with methanol was reasoned by calculating the transition states for the two putative structures (rac)-3a and (rac)-3b. The compound (rac)-3a is the kinetic product as inferred from the lower energies of its transition state (TS1). The 1 H and 13 C nuclear magnetic resonance (NMR) chemical shifts for these two candidate structures were calculated and compared with the experimental data using mean absolute error (MAE) and DP4 analyses. Therefore, the relative stereochemistry of (rac)-3a was established by the mechanism, MAE, and DP4 approaches. The hydroxyl group was acetylated to surpass the problem of signal overlapping of H5 and H6 in the 1 H NMR. The relative stereochemistry of the corresponding ester determined by NMR interpretation was in agreement with the structure of (rac)-3a.
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Affiliation(s)
- Elson S Alvarenga
- Department of Chemistry, Universidade Federal de Viçosa, Viçosa, Brazil
| | - Milena G Teixeira
- Department of Chemistry, Universidade Federal de Viçosa, Viçosa, Brazil
| | - Dayane T Lopes
- Department of Chemistry, Universidade Federal de Viçosa, Viçosa, Brazil
| | - Antonio J Demuner
- Department of Chemistry, Universidade Federal de Viçosa, Viçosa, Brazil
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Alvarenga ES, Santos JO, Moraes FC, Carneiro VM. Quantum mechanical approach for structure elucidation of novel halogenated sesquiterpene lactones. J Mol Struct 2019. [DOI: 10.1016/j.molstruc.2018.11.085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Moraes F, Alvarenga E, Demuner A, Viana V. Assignment of the relative and absolute stereochemistry of two novel epoxides using NMR and DFT-GIAO calculations. J Mol Struct 2018. [DOI: 10.1016/j.molstruc.2018.03.050] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Oliveira RP, Demuner AJ, Alvarenga ES, Barbosa LCA, de Melo Silva T. A novel alkaloid isolated from Crotalaria paulina and identified by NMR and DFT calculations. J Mol Struct 2018. [DOI: 10.1016/j.molstruc.2017.09.065] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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da Costa Resende G, Alvarenga ES. Structural elucidation of dioxa-cage compounds from tetrahydroisobenzofuran-1(3H)-one: analysis of NMR data and GIAO chemical shifts calculations. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2016; 54:968-974. [PMID: 27391981 DOI: 10.1002/mrc.4483] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 06/20/2016] [Accepted: 07/04/2016] [Indexed: 06/06/2023]
Abstract
The polycyclic compounds, especially the dioxa-cages, have attracted considerable attention in recent years. In our work, a series of 9β-substituted 3-oxo-4,11-dioxatetracyclo[5.2.1.15,8 .02,6 ]undecane compounds were unexpectedly isolated during bromination, chlorination and epoxidation reactions of the 3-hydroxy-3a,4,7,7a-tetrahydro-4,7-methanoisobenzofuran-1(3H)-one. After careful analysis of the NMR data, the chemical shifts of the isolated and the expected products were predicted by theoretical calculations using density functional theory and gauge including atomic orbitals. The best correlation between calculated and experimental data was evaluated by comparing mean absolute errors and applying DP4 probability methodology. Results from both approaches indicated a correct structural elucidation. Copyright © 2016 John Wiley & Sons, Ltd.
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Andernach L, Sandjo LP, Liermann JC, Schlämann R, Richter C, Ferner JP, Schwalbe H, Schüffler A, Thines E, Opatz T. Terphenyl Derivatives from Allantophomopsis lycopodina. JOURNAL OF NATURAL PRODUCTS 2016; 79:2718-2725. [PMID: 27731998 DOI: 10.1021/acs.jnatprod.6b00690] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Three secondary fungal metabolites 1-3 with a benzo[b]naphtho[2,1-d]furan skeleton were isolated from submerged cultures of the ascomycete Allantophomopsis lycopodina. The NMR-based structure elucidation was challenging due to a low H/C ratio of only 0.64 and 0.68, respectively. NMR measurements in two different solvents and the use of NMR experiments such as HSQC-TOCSY and LR-HSQMBC proved to be helpful in this respect. The proposed structures obtained from the comprehensive analysis of the NMR data were verified by comparison of recorded and computed NMR chemical shifts from quantum chemical calculations of several constitutional isomers and were further analyzed with the aid of the DP4 and DP4+ probabilities.
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Affiliation(s)
- Lars Andernach
- Institute of Organic Chemistry, Johannes Gutenberg-University , Duesbergweg 10-14, D-55128 Mainz, Germany
| | - Louis P Sandjo
- Institute of Organic Chemistry, Johannes Gutenberg-University , Duesbergweg 10-14, D-55128 Mainz, Germany
- Departamento de Ciências Farmacêuticas, Centro de Ciências da Saúde, Bloco J/K, Universidade Federal de Santa Catarina , Florianópolis 88040-900, SC, Brazil
| | - Johannes C Liermann
- Institute of Organic Chemistry, Johannes Gutenberg-University , Duesbergweg 10-14, D-55128 Mainz, Germany
| | - Ricardo Schlämann
- Institut für Biotechnologie und Wirkstoff-Forschung gGmbH , Erwin-Schrödinger-Straße 56, D-67663 Kaiserslautern, Germany
| | - Christian Richter
- Institute of Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance, Johann Wolfgang Goethe-University Frankfurt , Max-von-Laue-Straße 7, D-60438 Frankfurt am Main, Germany
| | - Jan-Peter Ferner
- Institute of Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance, Johann Wolfgang Goethe-University Frankfurt , Max-von-Laue-Straße 7, D-60438 Frankfurt am Main, Germany
| | - Harald Schwalbe
- Institute of Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance, Johann Wolfgang Goethe-University Frankfurt , Max-von-Laue-Straße 7, D-60438 Frankfurt am Main, Germany
| | - Anja Schüffler
- Institut für Biotechnologie und Wirkstoff-Forschung gGmbH , Erwin-Schrödinger-Straße 56, D-67663 Kaiserslautern, Germany
| | - Eckhard Thines
- Institut für Biotechnologie und Wirkstoff-Forschung gGmbH , Erwin-Schrödinger-Straße 56, D-67663 Kaiserslautern, Germany
- Institut für Mikrobiologie und Weinforschung, Johannes Gutenberg-University Mainz , Johann-Joachim-Becherweg 15, 55128 Mainz, Germany
| | - Till Opatz
- Institute of Organic Chemistry, Johannes Gutenberg-University , Duesbergweg 10-14, D-55128 Mainz, Germany
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