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Gabbani A, Taddeucci A, Bertuolo M, Pineider F, Aronica LA, Di Bari L, Pescitelli G, Zinna F. Magnetic Circular Dichroism Elucidates Molecular Interactions in Aggregated Chiral Organic Materials. Angew Chem Int Ed Engl 2024; 63:e202313315. [PMID: 37962845 DOI: 10.1002/anie.202313315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Revised: 10/20/2023] [Accepted: 11/14/2023] [Indexed: 11/15/2023]
Abstract
Chiral materials formed by aggregated organic compounds play a fundamental role in chiral optoelectronics, photonics and spintronics. Nonetheless, a precise understanding of the molecular interactions involved remains an open problem. Here we introduce magnetic circular dichroism (MCD) as a new tool to elucidate molecular interactions and structural parameters of a supramolecular system. A detailed analysis of MCD together with electronic circular dichroism spectra combined to ab initio calculations unveils essential information on the geometry and energy levels of a self-assembled thin film made of a carbazole di-bithiophene chiral molecule. This approach can be extended to a generality of chiral organic materials and can help rationalizing the fundamental interactions leading to supramolecular order. This in turn could enable a better understanding of structure-property relationships, resulting in a more efficient material design.
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Affiliation(s)
- Alessio Gabbani
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Via Moruzzi 13, 56124, Pisa, Italy
- Department of Physics and Astronomy, University of Florence, via Sansone 1, 50019, Sesto Fiorentino, FI, Italy
| | - Andrea Taddeucci
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Via Moruzzi 13, 56124, Pisa, Italy
- Current affiliation: Diamond Light Source Ltd., Fermi Avenue, Chilton, Didcot OX11 0DE, UK
| | - Marco Bertuolo
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Via Moruzzi 13, 56124, Pisa, Italy
| | - Francesco Pineider
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Via Moruzzi 13, 56124, Pisa, Italy
- Department of Physics and Astronomy, University of Florence, via Sansone 1, 50019, Sesto Fiorentino, FI, Italy
| | - Laura Antonella Aronica
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Via Moruzzi 13, 56124, Pisa, Italy
| | - Lorenzo Di Bari
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Via Moruzzi 13, 56124, Pisa, Italy
| | - Gennaro Pescitelli
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Via Moruzzi 13, 56124, Pisa, Italy
| | - Francesco Zinna
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Via Moruzzi 13, 56124, Pisa, Italy
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2
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Sun M, Ma X, Shao S, Jiang J, Li J, Tian J, Zhang J, Li L, Ye F, Li S. Atropisomeric 9,10-dihydrophenanthrene/bibenzyl trimers with anti-inflammatory and PTP1B inhibitory activities from Bletilla striata. Org Biomol Chem 2022; 20:4736-4745. [PMID: 35612380 DOI: 10.1039/d2ob00489e] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Two pairs of novel trimeric dihydrophenanthrene-bibenzyl-dihydrophenanthrene enantiomers (1 and2), the first examples of a dihydrophenanthrene dimer linked to a bibenzyl or dihydrophenanthrene through a C-O-C bond (3 and4), and a pair of rare polymers with a bibenzyl connected to C-8' of the dihydrophenanthro[b]furan moiety via a methylene (5), together with four known compounds (6-9) were isolated from the tubers of Bletilla striata. Their structures including the absolute configurations were determined using spectroscopic data analysis and ECD and NMR calculations, combined with the exciton chirality method or the reversed helicity rule. The atropisomerism of dihydrophenanthrenes and related polymers was considered based on their chiral optical properties, and QM torsion profile calculations, which revealed the racemic mixture form of the polymers. Compounds 4, 5b, 6a and 7b significantly inhibited the production of NO in LPS-induced BV-2 cells, with IC50 values ranging from 0.78 to 5.52 μM. Further mechanistic study revealed that 7b suppressed the expression of iNOS, and suppressed the phosphorylation of the p65 subunit to regulate the NF-κB signaling pathway. Furthermore, compounds 2b, 5a, 5b, 7a and 7b displayed significant protein tyrosine phosphatase 1B (PTP1B) inhibitory activities with IC50 values of 3.43-12.30 μM.
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Affiliation(s)
- Mohan Sun
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China.
| | - Xianjie Ma
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China.
| | - Siyuan Shao
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China.
| | - Jianwei Jiang
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China.
| | - Jiaan Li
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China.
| | - Jinying Tian
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China.
| | - Jianjun Zhang
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China.
| | - Li Li
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China.
| | - Fei Ye
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China.
| | - Shuai Li
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China.
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Zhang JY, Yang BB, Yang YD, Wang R, Li L. Specific chiroptical sensing of cysteine via ultrasound-assisted formation of disulfide bonds in aqueous solution. ULTRASONICS SONOCHEMISTRY 2022; 86:106007. [PMID: 35436673 PMCID: PMC9036132 DOI: 10.1016/j.ultsonch.2022.106007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 04/04/2022] [Accepted: 04/10/2022] [Indexed: 06/14/2023]
Abstract
Cysteine (Cys) can serve as a biomarker to indicate diseases or disorders, and its chiral sensing has attracted increasing attention. Herein, we established an ultrasound-facilitated chiral sensing method for Cys using 4-chloro-7-nitro-1,2,3-benzoxadiazole (NBD-Cl) and electronic circular dichroism (ECD) spectroscopy. The formation of chiral disulfide bonds induced degenerate exciton coupling between two NBD chromophores, resulting in intense Cotton effects (CEs) of the sensing product. The anisotropy factor (g) was linearly correlated with the enantiomeric excess of Cys across the visible region (400-500 nm), and other natural amino acids or biothiols did not interfere with the detection. This ultrasound-promoted efficient and specific chiral sensing method of Cys has potential for application in the diagnosis of related diseases.
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Affiliation(s)
- Jun-Yao Zhang
- Beijing Key Laboratory of Active Substances Discovery and Druggability Evaluation, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Bei-Bei Yang
- Beijing Key Laboratory of Active Substances Discovery and Druggability Evaluation, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Ya-Dong Yang
- Beijing Key Laboratory of Active Substances Discovery and Druggability Evaluation, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Ru Wang
- Beijing Key Laboratory of Active Substances Discovery and Druggability Evaluation, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Li Li
- Beijing Key Laboratory of Active Substances Discovery and Druggability Evaluation, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China.
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4
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Pescitelli G. ECD exciton chirality method today: a modern tool for determining absolute configurations. Chirality 2021; 34:333-363. [PMID: 34791704 PMCID: PMC9299504 DOI: 10.1002/chir.23393] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 10/26/2021] [Accepted: 10/27/2021] [Indexed: 02/02/2023]
Abstract
The application of the exciton chirality method (ECM) to interpret electronic circular dichroism (ECD) spectra is a well‐established and still popular approach to assign the absolute configuration (AC) of natural products, chiral organic compounds, and organometallic species. The method applies to compounds containing at least two chromophores with electric dipole allowed transitions (e.g., π–π* transitions). The exciton chirality rule correlates the sign of an exciton couplet (two ECD bands with opposite sign and similar intensity) with the overall molecular stereochemistry, including the AC. A correct application of the ECM requires three main prerequisites: (a) the knowledge of the molecular conformation, (b) the knowledge of the directions of the electric transition moments (TDMs), and (c) the assumption that the exciton coupling mechanism must be the major source of the observed ECD signals. All these prerequisites can be easily verified by means of quantum‐mechanical (QM) calculations. In the present review, we shortly introduce the general principles that underpin the use of the ECM for configurational assignments and survey its applications, both classic ones and some reported in the recent literature. Based on these examples, we will stress the advantages of the ECM but also the key requisites for its correct application. Additionally, we will discuss the dependence of the couplet sign on geometrical parameters (angles α,β,γ between TDMs), which can be helpful for discerning the sign of exciton chirality in ambiguous situations. Finally, we will present a molecular orbital (MO) description of the exciton coupling phenomenon.
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Affiliation(s)
- Gennaro Pescitelli
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Pisa, Italy
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5
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Zatout R, Masi M, Sangermano F, Vurro M, Zonno MC, Santoro E, Calabrò V, Superchi S, Evidente A. Drophiobiolins A and B, Bioactive Ophiobolan Sestertepenoids Produced by Dreschslera gigantea. JOURNAL OF NATURAL PRODUCTS 2020; 83:3387-3396. [PMID: 33074690 DOI: 10.1021/acs.jnatprod.0c00836] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Two new bioactive ophiobolan sestertepenoids, named drophiobiolins A and B (1 and 2) were isolated from Drechslera gigantea, a fungus proposed as a mycoherbicide for biocontrol of Digitaria sanguinalis. They were isolated together with ophiobolin A, the main metabolite, 6-epi-ophiobolin A, 3-anhydro-6-epi-ophiobolin A, and ophiobolin I. Drophiobolins A and B were characterized by NMR, HRESIMS, and chemical methods as 7-hydroxy-7-(6-hydroxy-6-methylheptan-2-yl)-1,9a-dimethyl-3-oxo-3,3a,6,6a,7,8,9,9a,10,10a-decahydrodicyclopenta [a,d][8]annulene-4-carbaldehyde and 6-(hydroxymethyl)-3',9,10a-trimethyl-5'-(2-methylprop-1-en-1-yl)-3a,4,4',5',10,10a-hexahydro-1H,3'H-spiro[dicyclopenta[a,d] [8]annulene-3,2'-furan]-5,7(2H,9aH)-dione. The relative configuration of drophiobolins A and B, which did not afford crystals suitable for X-ray analysis, was determined by NOESY experiments, while the absolute configuration was assigned by comparison of their experimental and TDDFT calculated electronic circular dichroism (ECD) spectra. The phytotoxic activity of drophiobolins A and B was tested by leaf-puncture assay on cultivated (Lycopersicon esculentum L.), as well as on host (Digitaria sanguinalis L.) and nonhost (Chenopodium album L.) weed plants, compared to that of ophiobolin A. Both of the newly identified ophiobolins showed significant phytotoxicity. Drophiobolins A and B exhibited cytotoxicity against Hela B cells with an IC50 value of 10 μM. However, they had a lesser or no effect against Hacat, H1299, and A431 cells when compared to that of ophiobolin A.
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Affiliation(s)
- Roukia Zatout
- Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Complesso Universitario Monte Sant'Angelo, Via Cintia 4, 80126 Napoli, Italy
- Laboratoire de Mycologie, de Biotechnologie et de l'Activité Microbienne (LaMyBAM), Département de Biologie Appliquée, Université des Frères Mentouri, Constantine1, BP, 325 Route de Aïn El Bey, 25017 Constantine, Algeria
| | - Marco Masi
- Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Complesso Universitario Monte Sant'Angelo, Via Cintia 4, 80126 Napoli, Italy
| | - Felicia Sangermano
- Dipartimento di Biologia, Università di Napoli Federico II, Complesso Universitario Monte Sant'Angelo, Via Cintia 4, 80126 Napoli, Italy
| | - Maurizio Vurro
- Istituto di Scienze delle Produzioni Alimentari, CNR, Via Amendola 122/O, 70126 Bari, Italy
| | - Maria Chiara Zonno
- Istituto di Scienze delle Produzioni Alimentari, CNR, Via Amendola 122/O, 70126 Bari, Italy
| | - Ernesto Santoro
- Dipartimento di Scienze, Università della Basilicata, Via dell'Ateneo Lucano 10, 85100 Potenza, Italy
| | - Viola Calabrò
- Dipartimento di Biologia, Università di Napoli Federico II, Complesso Universitario Monte Sant'Angelo, Via Cintia 4, 80126 Napoli, Italy
| | - Stefano Superchi
- Dipartimento di Scienze, Università della Basilicata, Via dell'Ateneo Lucano 10, 85100 Potenza, Italy
| | - Antonio Evidente
- Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Complesso Universitario Monte Sant'Angelo, Via Cintia 4, 80126 Napoli, Italy
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6
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Chiral cleft-like methanocyclooctadiindoles: Synthesis, circular dichroism and TDDFT study. Tetrahedron Lett 2020. [DOI: 10.1016/j.tetlet.2020.152302] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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7
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Górecki M, Frelek J. A Critical Appraisal of Dimolybdenum Tetraacetate Application in Stereochemical Studies of vic-Diols by Circular Dichroism. JOURNAL OF NATURAL PRODUCTS 2020; 83:955-964. [PMID: 32148042 DOI: 10.1021/acs.jnatprod.9b00800] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
This critical appraisal is intended for users of the dimolybdenum method, well-established in electronic circular dichroism (ECD) to determine the absolute configuration of vic-diols and, in particular, for experimental researchers not being experts in chiroptical methods. The main goal is to demonstrate how to avoid misleading and ambiguous conclusions resulting from the rigorous application of the helicity rule by limiting the analysis to the vic-diol unit alone. We particularly focused on multichromophoric systems, especially those that may interfere with the absorption of an in situ formed dimolybdenum tetraacetate-diol complex. In this context, examples are presented of vic-diols for which stereochemical assignment based solely on the helicity rule is ambiguous and does not necessarily lead to correct results. The motivation for choosing these examples was to demonstrate the impact of the structure of the substrate on the complexation process with the metal core and its selectivity. For each selected case, results obtained are analyzed in detail together with a discussion of existing restrictions and choice of a support method to increase the credibility of the conclusion. Based on seven both educational and challenging examples, it was shown that the dimolybdenum methodology can also be effectively applied to complex chromophoric systems, provided that other chiroptical methods and/or computational support verify obtained results.
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Affiliation(s)
- Marcin Górecki
- Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52 Street, 01-224 Warsaw, Poland
| | - Jadwiga Frelek
- Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52 Street, 01-224 Warsaw, Poland
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8
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Zhang S, Zhang L, Kou L, Yang Q, Qu B, Pescitelli G, Xie Z. Isolation, stereochemical study, and racemization of (±)‐pratenone A, the first naturally occurring 3‐(1‐naphthyl)‐2‐benzofuran‐1(3H)‐one polyketide from a marine‐derived actinobacterium. Chirality 2020; 32:299-307. [DOI: 10.1002/chir.23178] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 01/08/2020] [Accepted: 01/11/2020] [Indexed: 01/05/2023]
Affiliation(s)
- Shu‐Min Zhang
- School of PharmacyBinzhou Medical University Yantai China
| | - Lu Zhang
- School of PharmacyBinzhou Medical University Yantai China
| | - Li‐Juan Kou
- School of PharmacyBinzhou Medical University Yantai China
| | - Qiao‐Li Yang
- College of Life SciencesYantai University Yantai China
| | - Bo Qu
- College of Life SciencesYantai University Yantai China
| | - Gennaro Pescitelli
- Dipartimento di Chimica e Chimica IndustrialeUniversità di Pisa Pisa Italy
| | - Ze‐Ping Xie
- School of PharmacyBinzhou Medical University Yantai China
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Zhao WY, Song XY, Zhao L, Zou CX, Zhou WY, Lin B, Yao GD, Huang XX, Song SJ. Quassinoids from Picrasma quassioides and Their Neuroprotective Effects. JOURNAL OF NATURAL PRODUCTS 2019; 82:714-723. [PMID: 30917277 DOI: 10.1021/acs.jnatprod.8b00470] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Quassinoids are a class of highly oxygenated degraded triterpenoids exclusively discovered from plants of the Simaroubaceae family. In this study, eight new (1-8) and 15 known quassinoids (9-23) were isolated from an extract of the stems of Picrasma quassioides. The structures were elucidated by spectroscopic analysis and electronic circular dichroism spectra combined with quantum chemical calculations. Compounds 4 and 5 represent the first examples of 18-nor-quassinoids from P. quassioides. All isolates were screened for their neuroprotective activities toward H2O2-induced cell damage in SH-SY5Y cells. Further study revealed that the potential protective activities of these compounds appeared to occur via the suppression of cell apoptosis and downregulation of caspase-3 activation.
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Affiliation(s)
| | | | | | | | | | | | | | - Xiao-Xiao Huang
- Chinese People's Liberation Army 210 Hospital , Dalian 116021 , People's Republic of China
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10
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Mándi A, Kurtán T. Applications of OR/ECD/VCD to the structure elucidation of natural products. Nat Prod Rep 2019; 36:889-918. [DOI: 10.1039/c9np00002j] [Citation(s) in RCA: 97] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
OR, ECD and VCD are powerful methods to determine the absolute configuration of natural products either applied independently or in combination.
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Affiliation(s)
- Attila Mándi
- Department of Organic Chemistry
- University of Debrecen
- Debrecen
- Hungary
| | - Tibor Kurtán
- Department of Organic Chemistry
- University of Debrecen
- Debrecen
- Hungary
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11
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Pescitelli G. For a Correct Application of the CD Exciton Chirality Method: The Case of Laucysteinamide A. Mar Drugs 2018; 16:E388. [PMID: 30332852 PMCID: PMC6213868 DOI: 10.3390/md16100388] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 10/10/2018] [Accepted: 10/15/2018] [Indexed: 12/15/2022] Open
Abstract
The circular dichroism (CD) exciton chirality method (ECM) is a very popular approach for assigning the absolute configuration (AC) of natural products, thanks to its immediacy and ease of application. The sign of an exciton couplet (two electronic CD bands with opposite sign and similar intensity) can be directly correlated with the molecular stereochemistry, including the AC. However, a correct application of the ECM necessitates several prerequisites: knowledge of the molecular conformation; knowledge of transition moment direction; and preeminence of the exciton coupling mechanism with respect to other sources of CD signals. In recent years, by using quantum-chemical CD calculations, we have demonstrated that some previous applications of ECM were wrong or based on incorrect assumptions. In a recent publication of this journal (Mar. Drugs, 2017, 15(4), 121), the ECM was employed to assign the AC of a marine metabolite, laucysteinamide A. This is a further case of incorrect application of the method, where none of the aforementioned prerequisites is fully met. Using this example, we will discuss the criteria required for a correct application of the ECM.
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Affiliation(s)
- Gennaro Pescitelli
- Department of Chemistry and Industrial Chemistry, University of Pisa, Via G. Moruzzi 13, 56124 Pisa, Italy.
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12
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Masnyk M, Butkiewicz A, Górecki M, Luboradzki R, Paluch P, Potrzebowski MJ, Frelek J. In Depth Analysis of Chiroptical Properties of Enones Derived from Abietic Acid. J Org Chem 2018; 83:3547-3561. [PMID: 29490457 DOI: 10.1021/acs.joc.7b02911] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
With the use of inexpensive commercially available abietic acid, a whole series of abietane enones were prepared in high yields. The structures of all the products obtained were determined by comprehensive spectroscopic analysis with particular emphasis on the use of advanced NMR techniques, comparison with previously reported data and, where possible, by single crystal X-ray diffraction. However, in cases where X-ray crystallography was not applicable or compounds tested were unstable, a final stereochemical assignment could be inferred only by electronic circular dichroism (ECD) supported by vibrational circular dichroism to increase credibility. To reveal the relationship between structure and chiroptical properties, we used combined experimental and theoretical analysis of geometries, structural parameters, and chiroptical properties of all enones synthesized. A thorough analysis of their conformational flexibility by examining the effect of solvent and temperature on the ECD spectra was also used to achieve desired objectives. As a result, the impact of substituents adjacent to the enone chromophore on the conformation was determined by demonstrating that even slight changes in the position of hydroxyl and isopropyl groups attached to carbon C13 may substantially affect ECD curves' pattern, leading in some cases to Cotton effects sign reversal.
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Affiliation(s)
- Marek Masnyk
- Institute of Organic Chemistry , Polish Academy of Sciences , Kasprzaka 44/52 , 01-224 Warsaw , Poland
| | - Aleksandra Butkiewicz
- Institute of Organic Chemistry , Polish Academy of Sciences , Kasprzaka 44/52 , 01-224 Warsaw , Poland
| | - Marcin Górecki
- Institute of Organic Chemistry , Polish Academy of Sciences , Kasprzaka 44/52 , 01-224 Warsaw , Poland
| | - Roman Luboradzki
- Institute of Physical Chemistry , Polish Academy of Sciences , Kasprzaka 44/52 , 01-224 Warsaw , Poland
| | - Piotr Paluch
- Centre of Molecular and Macromolecular Studies , Polish Academy of Sciences , Sienkiewicza 112 , 90-363 Lodz , Poland
| | - Marek J Potrzebowski
- Centre of Molecular and Macromolecular Studies , Polish Academy of Sciences , Sienkiewicza 112 , 90-363 Lodz , Poland
| | - Jadwiga Frelek
- Institute of Organic Chemistry , Polish Academy of Sciences , Kasprzaka 44/52 , 01-224 Warsaw , Poland
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13
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Shi YM, Hu K, Pescitelli G, Liu M, Li XN, Du X, Xiao WL, Sun HD, Puno PT. Schinortriterpenoids with Identical Configuration but Distinct ECD Spectra Generated by Nondegenerate Exciton Coupling. Org Lett 2018; 20:1500-1504. [PMID: 29498864 DOI: 10.1021/acs.orglett.8b00149] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Yi-Ming Shi
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, Yunnan, People’s Republic of China
| | - Kun Hu
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, Yunnan, People’s Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People’s Republic of China
| | - Gennaro Pescitelli
- Dipartimento di Chimicae Chimica Industriale, Università di Pisa, Via Moruzzi 13, 56124, Pisa, Italy
| | - Miao Liu
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, Yunnan, People’s Republic of China
| | - Xiao-Nian Li
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, Yunnan, People’s Republic of China
| | - Xue Du
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, Yunnan, People’s Republic of China
| | - Wei-Lie Xiao
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, Yunnan, People’s Republic of China
| | - Han-Dong Sun
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, Yunnan, People’s Republic of China
| | - Pema-Tenzin Puno
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, Yunnan, People’s Republic of China
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14
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M. dos Santos Jr. F, Bicalho KU, Calisto ÍH, S. Scatena G, Fernandes JB, Cass QB, Batista Jr. JM. Scope of the 2(5H)-furanone helicity rule: a combined ECD, VCD, and DFT investigation. Org Biomol Chem 2018; 16:4509-4516. [DOI: 10.1039/c8ob01085d] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Combination of ECD, VCD and DFT calculations revealed a possible exception to the widely used helicity rule of the 2(5H)-furanone chromophore.
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Affiliation(s)
| | - Keylla U. Bicalho
- Institute of Chemistry
- São Paulo State University – UNESP
- Araraquara
- Brazil
| | - Ítalo H. Calisto
- Department of Chemistry
- Federal University of São Carlos – UFSCar
- São Carlos
- Brazil
| | - Gabriel S. Scatena
- Department of Chemistry
- Federal University of São Carlos – UFSCar
- São Carlos
- Brazil
| | - João B. Fernandes
- Department of Chemistry
- Federal University of São Carlos – UFSCar
- São Carlos
- Brazil
| | - Quezia B. Cass
- Department of Chemistry
- Federal University of São Carlos – UFSCar
- São Carlos
- Brazil
| | - João M. Batista Jr.
- Department of Chemistry
- Federal University of São Carlos – UFSCar
- São Carlos
- Brazil
- Institute of Science and Technology
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15
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Pescitelli G, Di Bari L. Revision of the Absolute Configuration of Preussilides A-F Established by the Exciton Chirality Method. JOURNAL OF NATURAL PRODUCTS 2017; 80:2855-2859. [PMID: 29039947 DOI: 10.1021/acs.jnatprod.7b00740] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
In a recent contribution to this Journal (J. Nat. Prod. 2017, 80, 1531-1540), Noumeur et al. reported the isolation and structure elucidation of six novel polyketides named preussilides A-F, endowed with remarkable antiproliferative activity. The absolute configuration of the new compounds was established mainly by analyzing exciton-coupled electronic circular dichroism (ECD) spectra. However, the application of the exciton chirality method (ECM) was incorrect, because the chirality defined by transition moments was assigned in a wrong way. A correct application of the ECM, substantiated by time-dependent density functional theory (TDDFT) calculations of ECD spectra, led us to revise the absolute configuration of Preussilides A-F. A brief discussion on the criteria required for a correct application of the ECM is also presented.
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Affiliation(s)
- Gennaro Pescitelli
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa , Via Moruzzi 13, 56124 Pisa, Italy
| | - Lorenzo Di Bari
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa , Via Moruzzi 13, 56124 Pisa, Italy
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