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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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Gomes SF, Alvarenga ES, Baia VC, Oliveira DF. N-Phenylnorbornenesuccinimide derivatives, agricultural defensive, and enzymatic target selection. PEST MANAGEMENT SCIENCE 2024; 80:3278-3292. [PMID: 38372427 DOI: 10.1002/ps.8031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 02/06/2024] [Accepted: 02/14/2024] [Indexed: 02/20/2024]
Abstract
BACKGROUND Faced with the need to develop new herbicides with modes of action different to those observed for existing agrochemicals, one of the most promising strategies employed by synthetic chemists involves the structural modification of molecules found in natural products. Molecules containing amides, imides, and epoxides as functional groups are prevalent in nature and find extensive application in synthesizing more intricate compounds due to their biological properties. In this context, this paper delineates the synthesis of N-phenylnorbornenesuccinimide derivatives, conducts biological assays, and carries out in silico investigation of the protein target associated with the most potent compound in plant organisms. The phytotoxic effects of the synthesized compounds (2-29) were evaluated on Allium cepa, Bidens pilosa, Cucumis sativus, Sorghum bicolor, and Solanum lycopersicum. RESULTS Reaction of endo-bicyclo[2.2.1]hept-5-ene-3a,7a-dicarboxylic anhydride (1) with aromatic amines led to the N-phenylnorbornenesuccinic acids (2-11) with yields ranging from 75% to 90%. Cyclization of compounds (2-11) in the presence of acetic anhydride and sodium acetate afforded N-phenylnorbornenesuccinimides (12-20) with yields varying from 65% to 89%. Those imides were then subjected to epoxidation reaction to afford N-phenylepoxynorbornanesuccimides (21-29) with yields from 60% to 90%. All compounds inhibited the growth of seedlings of the plants evaluated. Substance 23 was the most active against the plants tested, inhibiting 100% the growth of all species in all concentrations. Cyclophilin was found to be the enzymatic target of compound 23. CONCLUSION These findings suggest that derivatives of N-phenylnorbornenesuccinimide are promising compounds in the quest for more selective and stable agrochemicals. This perspective reinforces the significance of these derivatives as potential innovative herbicides and emphasizes the importance of further exploring their biological activity on weeds. © 2024 Society of Chemical Industry.
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Affiliation(s)
- Sabriny F Gomes
- Department of Chemistry, Universidade Federal de Viçosa, Viçosa, Brazil
| | - Elson S Alvarenga
- Department of Chemistry, Universidade Federal de Viçosa, Viçosa, Brazil
| | - Vitor C Baia
- Department of Chemistry, Universidade Federal de Viçosa, Viçosa, Brazil
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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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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: 3] [Impact Index Per Article: 1.0] [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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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: 0.8] [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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Assignment of the relative stereochemistry of two novel vicinal dibromo compounds using NMR and DFT-GIAO calculations. J Mol Struct 2020. [DOI: 10.1016/j.molstruc.2020.128157] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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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: 4] [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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Flourat AL, Haudrechy A, Allais F, Renault JH. (S)-γ-Hydroxymethyl-α,β-butenolide, a Valuable Chiral Synthon: Syntheses, Reactivity, and Applications. Org Process Res Dev 2019. [DOI: 10.1021/acs.oprd.9b00468] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Amandine L. Flourat
- URD Agro-Biotechnologies Industrielles (ABI), CEBB, AgroParisTech, 51110 Pomacle, France
- Institut de Chimie Moléculaire de Reims, UMR CNRS 7312, SFR Condorcet FR CNRS 3417, Université de Reims Champagne Ardenne BP 1039, F-51687 Reims Cedex, France
| | - Arnaud Haudrechy
- Institut de Chimie Moléculaire de Reims, UMR CNRS 7312, SFR Condorcet FR CNRS 3417, Université de Reims Champagne Ardenne BP 1039, F-51687 Reims Cedex, France
| | - Florent Allais
- URD Agro-Biotechnologies Industrielles (ABI), CEBB, AgroParisTech, 51110 Pomacle, France
| | - Jean-Hugues Renault
- Institut de Chimie Moléculaire de Reims, UMR CNRS 7312, SFR Condorcet FR CNRS 3417, Université de Reims Champagne Ardenne BP 1039, F-51687 Reims Cedex, France
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