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Wu A, Chen Q, Feng J, Ye J, Xu X. Accurate Structural Elucidation of Samoquasine A and an Unknown Homologue Using a Computation-Based Machine Learning Protocol. J Phys Chem A 2024; 128:4830-4837. [PMID: 38850258 DOI: 10.1021/acs.jpca.4c02916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2024]
Abstract
The structure of samoquasine A has long been a subject of controversy, which was resolved only upon its successful total synthesis. We examined the structures of the associated compounds using the state-of-the-art SVM-M protocol. The method accurately discriminated all putative structures historically attributed to samoquasine A from a pool of 48 isomeric structures, confirming that samoquasine A is indeed identical to perlolidine. Furthermore, by applying the SVM-M protocol to an additional pool of 67 isomeric structures, we successfully assigned a yet unknown natural product, initially misidentified as perlolidine, as a novel oxime, (E)-3H-cyclopenta[c]quinolin-3-one oxime, representing the first reported cyclone oxime-quinoline natural product.
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Affiliation(s)
- Anan Wu
- Fujian Provincial Key Laboratory for Theoretical and Computational Chemistry, Departmental of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, P. R. China
| | - Qiwen Chen
- Fujian Provincial Key Laboratory for Theoretical and Computational Chemistry, Departmental of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, P. R. China
| | - Jin Feng
- Fujian Provincial Key Laboratory for Theoretical and Computational Chemistry, Departmental of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, P. R. China
| | - Jianliang Ye
- Fujian Provincial Key Laboratory for Theoretical and Computational Chemistry, Departmental of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, P. R. China
| | - Xin Xu
- Collaborative Innovation Center of Chemistry for Energy Materials, Shanghai; Key Laboratory of Molecular Catalysis and Innovative Materials; MOE Key Laboratory of Computational Physical Sciences; Department of Chemistry, Fudan University, Shanghai 200438, China
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2
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Elyashberg M, Tyagarajan S, Mandal M, Buevich AV. Enhancing Efficiency of Natural Product Structure Revision: Leveraging CASE and DFT over Total Synthesis. Molecules 2023; 28:molecules28093796. [PMID: 37175206 PMCID: PMC10180399 DOI: 10.3390/molecules28093796] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 04/21/2023] [Accepted: 04/24/2023] [Indexed: 05/15/2023] Open
Abstract
Natural products remain one of the major sources of coveted, biologically active compounds. Each isolated compound undergoes biological testing, and its structure is usually established using a set of spectroscopic techniques (NMR, MS, UV-IR, ECD, VCD, etc.). However, the number of erroneously determined structures remains noticeable. Structure revisions are very costly, as they usually require extensive use of spectroscopic data, computational chemistry, and total synthesis. The cost is particularly high when a biologically active compound is resynthesized and the product is inactive because its structure is wrong and remains unknown. In this paper, we propose using Computer-Assisted Structure Elucidation (CASE) and Density Functional Theory (DFT) methods as tools for preventive verification of the originally proposed structure, and elucidation of the correct structure if the original structure is deemed to be incorrect. We examined twelve real cases in which structure revisions of natural products were performed using total synthesis, and we showed that in each of these cases, time-consuming total synthesis could have been avoided if CASE and DFT had been applied. In all described cases, the correct structures were established within minutes of using the originally published NMR and MS data, which were sometimes incomplete or had typos.
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Affiliation(s)
- Mikhail Elyashberg
- Advanced Chemistry Development Inc. (ACD/Labs), Toronto, ON M5C 1B5, Canada
| | | | - Mihir Mandal
- Medicinal Chemistry, Merck & Co., Inc., Kenilworth, NJ 07033, USA
| | - Alexei V Buevich
- Analytical Research and Development, Merck & Co., Inc., Kenilworth, NJ 07033, USA
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3
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Buccini M, Tham L, Dhoro F, Skelton BW, Williams CM, Piggott MJ. Toward the Total Synthesis of Alpkinidine: Synthesis of Haloquinone CE Ring System Synthons and Attempted Nucleophilic Bisannulation. ACS OMEGA 2022; 7:19080-19092. [PMID: 35721899 PMCID: PMC9202046 DOI: 10.1021/acsomega.2c02116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Accepted: 05/13/2022] [Indexed: 05/08/2023]
Abstract
Model chemistry involving the bisannulation of 2,3-dichloro-1,4-naphthoquinone with the ester enolate derived from ethyl o-nitrophenylacetic acid, which rapid assembled the ABCD ring system of a pentacyclic pyrroloacridine, has been applied to the attempted synthesis of the marine natural product alpkinidine. The reaction of ethyl o-nitrophenylacetic acid with 6,7-dichloro-2-methylisoquinoline-1,5,8(2H)-trione, required to extend the model strategy to alpkinidine, was unfruitful, giving only complex mixtures. Efforts to direct the regiochemistry of the key Michael substitution step using 6-bromo-2-methylisoquinoline-1,5,8(2H)-trione afforded an adduct sharing the complete carbon skeleton of alpkinidine, but this could not be elaborated to the natural product.
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Affiliation(s)
- Marco Buccini
- Chemistry,
School of Molecular Sciences, University
of Western Australia, Perth 6009, Australia
| | - Louisa Tham
- Chemistry,
School of Molecular Sciences, University
of Western Australia, Perth 6009, Australia
| | - Francis Dhoro
- Chemistry,
School of Molecular Sciences, University
of Western Australia, Perth 6009, Australia
| | - Brian W. Skelton
- Chemistry,
School of Molecular Sciences, University
of Western Australia, Perth 6009, Australia
| | - Craig M. Williams
- School
of Chemistry and Molecular Biosciences, University of Queensland, Brisbane 4072, Queensland, Australia
| | - Matthew J. Piggott
- Chemistry,
School of Molecular Sciences, University
of Western Australia, Perth 6009, Australia
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4
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Buccini M, Dhoro F, Tham L, Skelton BW, Williams CM, Piggott MJ. Toward the Total Synthesis of Alpkinidine: Michael Addition to Isoquinolinetrione CE Ring-System Synthons. ACS OMEGA 2022; 7:19093-19105. [PMID: 35722017 PMCID: PMC9202020 DOI: 10.1021/acsomega.2c02117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Accepted: 05/13/2022] [Indexed: 06/15/2023]
Abstract
Strategies toward the total synthesis of the marine pyrroloacridine alkaloid alpkinidine have been explored, focusing on linking quinonoid CE ring-system synthons with the A ring, followed by condensation to form the B and D rings. The key Michael addition of the ester enolate derived from ethyl o-nitrophenylacetate to 2-methylisoquinoline-1,5,8(2H)-trione proceeded with the wrong regiochemistry. This issue was addressed by incorporating the D-ring nitrogen at an earlier stage, affording advanced intermediates possessing the complete carbon skeleton of alpkinidine. However, attempts to close the D and B rings were unsuccessful. The novel isoquinolinetriones reported here, and the general strategy of connecting CE- and A-ring synthons through Michael additions, may be useful in the synthesis of other pyrrolo- and pyridoacridines, in particular the anticancer lead neoamphimedine and analogues.
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Affiliation(s)
- Marco Buccini
- Chemistry,
School of Molecular Sciences, University
of Western Australia, Perth 6009, Australia
| | - Francis Dhoro
- Chemistry,
School of Molecular Sciences, University
of Western Australia, Perth 6009, Australia
| | - Louisa Tham
- Chemistry,
School of Molecular Sciences, University
of Western Australia, Perth 6009, Australia
| | - Brian W. Skelton
- Chemistry,
School of Molecular Sciences, University
of Western Australia, Perth 6009, Australia
| | - Craig M. Williams
- School
of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Matthew J. Piggott
- Chemistry,
School of Molecular Sciences, University
of Western Australia, Perth 6009, Australia
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5
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Domzalska‐Pieczykolan A, Funes‐Ardoiz I, Furman B, Bolm C. Selective Approaches to α‐ and β‐Arylated Vinyl Ethers. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202109801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
| | - Ignacio Funes‐Ardoiz
- Departamento de Química Centro de Investigación en Síntesis Química (CISQ) University of La Rioja Madre de Dios 53 26006 Logroño Spain
| | - Bartłomiej Furman
- Institute of Organic Chemistry Polish Academy of Sciences Kasprzaka 44/52 01-224 Warsaw Poland
| | - Carsten Bolm
- Institut für Organische Chemie RWTH Aachen University Landoltweg 1 52074 Aachen Germany
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6
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Domzalska-Pieczykolan A, Funes-Ardoiz I, Furman B, Bolm C. Selective Approaches to α- and β-Arylated Vinyl Ethers. Angew Chem Int Ed Engl 2022; 61:e202109801. [PMID: 34758166 PMCID: PMC9299197 DOI: 10.1002/anie.202109801] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 11/09/2021] [Indexed: 11/09/2022]
Abstract
We developed simple and efficient protocols for palladium‐catalyzed regioselective α‐ and β‐arylations of structurally diverse vinyl ethers. Both catalytic methods proceed under relatively mild reactions conditions applying to a broad substrate range including more complex compounds providing arylated glucal or isochromene. Lacking the common requirement of a large reagent excess, the transformations are highly economic and limiting the waste production. Results from computational studies (DFT) provided insight into the key factors determining the pronounced regioselectivities of the investigated reactions.
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Affiliation(s)
| | - Ignacio Funes-Ardoiz
- Departamento de Química, Centro de Investigación en Síntesis Química (CISQ), University of La Rioja, Madre de Dios 53, 26006, Logroño, Spain
| | - Bartłomiej Furman
- Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224, Warsaw, Poland
| | - Carsten Bolm
- Institut für Organische Chemie, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany
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7
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Marsicano V, Arcadi A, Chiarini M, Fabrizi G, Goggiamani A, Iazzetti A. Sequential condensation/biannulation reactions of β-(2-aminophenyl)-α,β-ynones with 1,3-dicarbonyls. Org Biomol Chem 2021; 19:5177-5190. [PMID: 34042150 DOI: 10.1039/d1ob00795e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A divergent domino condensation/biannulation reaction of β-(2-aminophenyl) α,β-ynones with 1,3-dicarbonyls to construct a polycyclic 4H-pyrano[3,4-c]quinoline core has been developed. The p-TsOH·H2O catalyzed reaction of β-(2-aminophenyl) α,β-ynones with β-ketoesters in ethanol proceeds with good to excellent yields to provide a simple and effective method for the synthesis of functionalized 4H-pyrano[3,4-c]quinolinones. Further elaboration of these latter derivatives with an excess of 20% NH4OH in EtOH at 50 °C helps achieve the synthesis of the perlodinine analogues benzo[c][2,7]naphthyridin-4(3H)-one derivatives in high yields. Moreover, the p-TsOH·H2O mediated reaction of β-(2-aminophenyl) α,β-ynones with β-di-ketones leads to the formation of a variety of structurally diverse 4H-pyrano[3,4-c]quinoline polycyclic ketals by the incorporation of an alcohol solvent molecule in a cascade fashion.
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Affiliation(s)
- Vincenzo Marsicano
- Dipartimento di Scienze Fisiche e Chimiche, Università di L'Aquila, Via Vetoio- 67010 Coppito (AQ), Italy.
| | - Antonio Arcadi
- Dipartimento di Scienze Fisiche e Chimiche, Università di L'Aquila, Via Vetoio- 67010 Coppito (AQ), Italy.
| | - Marco Chiarini
- Facoltà di Bioscienze e Tecnologie Agro-alimentari e Ambientali, Università di Teramo, Via R. Balzarini 1, 64100 - Teramo (Te), Italy
| | - Giancarlo Fabrizi
- Dipartimento di Chimica e Tecnologie del Farmaco, Sapienza, Università di Roma, P.le A. Moro 5, 00185 Rome, Italy
| | - Antonella Goggiamani
- Dipartimento di Chimica e Tecnologie del Farmaco, Sapienza, Università di Roma, P.le A. Moro 5, 00185 Rome, Italy
| | - Antonia Iazzetti
- Dipartimento di Chimica e Tecnologie del Farmaco, Sapienza, Università di Roma, P.le A. Moro 5, 00185 Rome, Italy
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8
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Kawazoe R, Matsuo Y, Saito Y, Tanaka T. Computationally Assisted Structural Revision of Flavoalkaloids with a Seven-Membered Ring: Aquiledine, Isoaquiledine, and Cheliensisine. JOURNAL OF NATURAL PRODUCTS 2020; 83:3347-3353. [PMID: 33081470 DOI: 10.1021/acs.jnatprod.0c00691] [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
Aquiledine and cheliensisine are flavoalkaloids isolated from Aquilegia ecalcarata and Goniothalamus cheliensis, respectively. Different structures have been proposed for these flavoalkaloids; however, their 1H and 13C NMR spectroscopic data were virtually identical. In this study, the structures of aquiledine and cheliensisine were revised on the basis of the DFT calculation of NMR data including DP4+ and J-DP4 analysis, as well as specific rotations. Similarly, the structure of isoaquiledine, a regioisomer of aquiledine, was also revised. A biosynthetic pathway of these flavoalkaloids is proposed.
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Affiliation(s)
- Rina Kawazoe
- Graduate School of Biomedical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan
| | - Yosuke Matsuo
- Graduate School of Biomedical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan
| | - Yoshinori Saito
- Graduate School of Biomedical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan
| | - Takashi Tanaka
- Graduate School of Biomedical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan
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