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Perumal K, Palanisamy N, Hemamalini V, Shankar B, Shanthi M, Ramesh S. Unveiling Na 2-Eosin Y-Catalyzed and Water-Assisted Visible-Light Activation of Oxygen Molecules for the Dicarbonylation of Pyrazole Amines. J Org Chem 2024; 89:13556-13574. [PMID: 39255784 DOI: 10.1021/acs.joc.4c01741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/12/2024]
Abstract
A novel approach employing visible light-mediated activation of triplet oxygen molecules has been established. The reaction occurs at room temperature between pyrazole amine and phenylglyoxal monohydrate in the presence of Na2-eosin Y. Water played the dual role of solvent and reagent/additive. Photoactivation of triplet oxygen species was used to demonstrate the initiation of the hydrogen atom transfer (HAT) process. The conversion of the reaction mixture was found to be dependent on the amount of water present. Control experiments confirmed the importance of light, the photocatalyst, oxygen, the base, and water. The process tolerated various substitutions in both pyrazole amine and phenylglyoxal derivatives, enabling the synthesis of various dicarbonylpyrazole amines 15 and pyrazolooxazine derivatives 16 in moderate to good yields. 2 equiv of phenylglyoxal 10 gave a different reaction pathway, yielding highly diastereoselective pyrazolooxazine derivatives, confirmed by X-ray diffraction analysis. Collectively, this sustainable and environmentally friendly synthetic technique offers a promising method for the efficient preparation of pyrazole-based heterocyclic compounds. The high regioselectivity observed during the formation of trans-tetrahydropyrazolo[3,4-d][1,3]oxazine has been clarified through computational methods. These investigations emphasize the underlying factors and mechanisms that encourage the formation of this specific product, providing valuable insights into the reaction's selectivity and efficiency.
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Affiliation(s)
- Karuppaiah Perumal
- Department of Chemistry, School of Chemical and Biotechnology, SASTRA Deemed University, Thanjavur, Tamil Nadu 613 401, India
| | - Nivedhitha Palanisamy
- Department of Chemistry, School of Chemical and Biotechnology, SASTRA Deemed University, Thanjavur, Tamil Nadu 613 401, India
| | - Vijayakumar Hemamalini
- Department of Chemistry, School of Chemical and Biotechnology, SASTRA Deemed University, Thanjavur, Tamil Nadu 613 401, India
| | - Bhaskaran Shankar
- Department of Chemistry, Thiagarajar College of Engineering, Madurai, Tamil Nadu 625 015, India
| | - Markabandhu Shanthi
- Department of Chemistry, School of Chemical and Biotechnology, SASTRA Deemed University, Thanjavur, Tamil Nadu 613 401, India
| | - Subburethinam Ramesh
- Department of Chemistry, School of Chemical and Biotechnology, SASTRA Deemed University, Thanjavur, Tamil Nadu 613 401, India
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2
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Koser L, Bach T. Total Synthesis of (-)-5-Deoxyenterocin and Attempted Late-Stage Functionalization Reactions. Chemistry 2023; 29:e202301996. [PMID: 37452638 DOI: 10.1002/chem.202301996] [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: 06/23/2023] [Revised: 07/14/2023] [Accepted: 07/14/2023] [Indexed: 07/18/2023]
Abstract
The first total synthesis of (-)-5-deoxyenterocin has been accomplished starting from pentane-1,3,5-triol (16 steps in the longest linear sequence, 0.2 % overall yield). (-)-Menthone served as the source of chirality to distinguish the enantiotopic hydroxymethyl groups of the substrate. Key steps of the synthesis include two aldol reactions to either end of the C5 -skeleton, a diastereoselective hydroxylation reaction and a biomimetic twofold intramolecular aldol reaction as the final step. Although this step suffered from geometrical constraints and was low yielding (10 %), enough synthetic material could be secured to substantiate the relative and absolute configuration of the natural product. Additional experiments were directed toward a C-H functionalization at carbon atom C5. Despite the fact that several protocols could be successfully applied to (3aR)-(+)-sclareolide as model substrate, (-)-5-deoxyenterocin withstood any selective functionalization.
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Affiliation(s)
- Lilla Koser
- Department Chemie and Catalysis Research Center (CRC), School of Natural Sciences, Technische Universität München, Lichtenbergstraße 4, 85747, Garching, Germany
| | - Thorsten Bach
- Department Chemie and Catalysis Research Center (CRC), School of Natural Sciences, Technische Universität München, Lichtenbergstraße 4, 85747, Garching, Germany
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3
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Huang C, Cui H, Ren H, Zhao H. Investigation of the Biosynthetic Mechanism of Bipentaromycin Featuring an Unprecedented Cyclic Head-to-Tail Dimeric Scaffold. JACS AU 2023; 3:195-203. [PMID: 36711095 PMCID: PMC9875255 DOI: 10.1021/jacsau.2c00594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Revised: 12/17/2022] [Accepted: 12/19/2022] [Indexed: 06/18/2023]
Abstract
Bipentaromycins are heterodimeric aromatic polyketides featuring two distinctive 5/6/6/6/5 pentacyclic ring systems and exhibit antibacterial activities. However, their overall biosynthetic mechanism, particularly the mechanism for early-stage modifications, such as hydrogenation and methylation, and late-stage dimerization, remains unknown. Herein, by integrating heterologous expression, isotope labeling, gene knockout and complementation, and computational modeling, we determined the biosynthetic origin of the skeleton, identified the enzymes involved in stereo-/regioselective hydrogenation and methylation, and provided new mechanistic insights into the dimerization. This work not only deciphers the biosynthetic mechanism of bipentaromycins but also provides new strategies for creating biologically active dimeric pharmacophores for drug discovery and development.
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Affiliation(s)
- Chunshuai Huang
- Carl
R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Haiyang Cui
- Carl
R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Hengqian Ren
- Department
of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Huimin Zhao
- Carl
R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Department
of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Department
of Biochemistry, University of Illinois
at Urbana-Champaign, Urbana, Illinois 61801, United States
- Department
of Chemistry, University of Illinois at
Urbana-Champaign, Urbana, Illinois 61801, United States
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4
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Fan W. Synthesis of 1,2-Dicarbonyls from Five-Membered Cyclic Enamines and Arylglyoxal Hydrates under Metal-Free Conditions. HETEROCYCLES 2023. [DOI: 10.3987/com-23-14827] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 04/03/2023]
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5
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Koser L, Grassin C, Merten C, Bach T. Absolute Configuration of the Polyketide Natural Product (-)-Enterocin. Org Lett 2022; 24:6903-6907. [PMID: 36130083 DOI: 10.1021/acs.orglett.2c02525] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The absolute configuration of the polyketide natural product (-)-enterocin was established by two independent approaches. In the first approach, synthetic enterocin with a defined configuration was compared to the natural product. While identical in all scalar properties, the compound displayed an opposite specific rotation and a different chiral HPLC retention time when compared with (-)-enterocin. In a second approach, the vibrational circular dichroism (VCD) of the natural product was measured and shown to be opposite to the calculated VCD of its enantiomer.
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Affiliation(s)
- Lilla Koser
- TUM School of Natural Sciences, Department Chemie and Catalysis Research Center (CRC), Technische Universität München, 85747 Garching, Germany
| | - Corentin Grassin
- Organische Chemie II, Fakultät für Chemie und Biochemie, Ruhr-Universität Bochum, Universitätsstraße 150, 44801 Bochum, Germany
| | - Christian Merten
- Organische Chemie II, Fakultät für Chemie und Biochemie, Ruhr-Universität Bochum, Universitätsstraße 150, 44801 Bochum, Germany
| | - Thorsten Bach
- TUM School of Natural Sciences, Department Chemie and Catalysis Research Center (CRC), Technische Universität München, 85747 Garching, Germany
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Liu M, Zhang X, Li G. Structural and Biological Insights into the Hot‐spot Marine Natural Products Reported from 2012 to 2021. CHINESE J CHEM 2022. [DOI: 10.1002/cjoc.202200129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Mingyu Liu
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy Ocean University of China Qingdao 266003 China
- State Key Laboratory of Microbial Technology Shandong University Qingdao 266237 China
| | - Xingwang Zhang
- State Key Laboratory of Microbial Technology Shandong University Qingdao 266237 China
| | - Guoqiang Li
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy Ocean University of China Qingdao 266003 China
- Laboratory of Marine Drugs and Biological Products, National Laboratory for Marine Science and Technology Qingdao 266235 China
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Koser L, Lechner VM, Bach T. Biomimetic Total Synthesis of Enterocin. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202108157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Lilla Koser
- Technische Universität München School of Natural Sciences Department of Chemistry and Catalysis Research Center Lichtenbergstrasse 4 85747 Garching Germany
| | - Vivian Miles Lechner
- Technische Universität München School of Natural Sciences Department of Chemistry and Catalysis Research Center Lichtenbergstrasse 4 85747 Garching Germany
| | - Thorsten Bach
- Technische Universität München School of Natural Sciences Department of Chemistry and Catalysis Research Center Lichtenbergstrasse 4 85747 Garching Germany
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Koser L, Lechner VM, Bach T. Biomimetic Total Synthesis of Enterocin. Angew Chem Int Ed Engl 2021; 60:20269-20273. [PMID: 34278701 PMCID: PMC8457242 DOI: 10.1002/anie.202108157] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Indexed: 02/06/2023]
Abstract
The first chemical total synthesis of the highly oxygenated polyketide enterocin has been accomplished. The key step of the synthesis was a late‐stage biomimetic reaction cascade involving two intramolecular aldol reactions in which each step proceeded in 52 % yield (averaged) and which established four of the seven stereogenic centers. The pivotal precursor for the cascade reaction was assembled from three readily available building blocks. A chiral dithioacetal with two stereogenic centers originating from L‐arabinose represented the core fragment to both ends of which the other building blocks were attached by aldol reactions. The remaining stereogenic center was installed by Davis oxygenation immediately prior to the key step.
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Affiliation(s)
- Lilla Koser
- Technische Universität München, School of Natural Sciences, Department of Chemistry and Catalysis Research Center, Lichtenbergstrasse 4, 85747, Garching, Germany
| | - Vivian Miles Lechner
- Technische Universität München, School of Natural Sciences, Department of Chemistry and Catalysis Research Center, Lichtenbergstrasse 4, 85747, Garching, Germany
| | - Thorsten Bach
- Technische Universität München, School of Natural Sciences, Department of Chemistry and Catalysis Research Center, Lichtenbergstrasse 4, 85747, Garching, Germany
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Hu Z, Ye Y, Zhang Y. Large-scale culture as a complementary and practical method for discovering natural products with novel skeletons. Nat Prod Rep 2021; 38:1775-1793. [PMID: 33650608 DOI: 10.1039/d0np00069h] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Covering: up to July 2020Fungal metabolites with diverse and novel scaffolds can be assembled from well-known biosynthetic precursors through various mechanisms. Recent examples of novel alkaloids (e.g., cytochalasans and diketopiperazine derivatives), terpenes (e.g., sesterterpenes and diterpenes) and polyketides produced by fungi are presented through case studies. We show that large-scale culture is a complementary and practical method for genome mining and OSMAC approaches to discover natural products of unprecedented skeletal classes from fungi. We also summarize the discovery strategies and challenges for characterizing these compounds.
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Affiliation(s)
- Zhengxi Hu
- Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei Province, People's Republic of China.
| | - Ying Ye
- Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei Province, People's Republic of China.
| | - Yonghui Zhang
- Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei Province, People's Republic of China.
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10
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Cowled MS, Lacey E, Karuso P, Piggott AM. Rechoreographing Enterocin’s Ballet of Isomers: Structure Revision of Enterocins C, D, and F. Org Lett 2020; 22:9688-9692. [DOI: 10.1021/acs.orglett.0c03745] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Michael S. Cowled
- Department of Molecular Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Ernest Lacey
- Department of Molecular Sciences, Macquarie University, Sydney, NSW 2109, Australia
- Microbial Screening Technologies, Smithfield, NSW 2164, Australia
| | - Peter Karuso
- Department of Molecular Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Andrew M. Piggott
- Department of Molecular Sciences, Macquarie University, Sydney, NSW 2109, Australia
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Cowled MS, Vuong D, Crombie A, Lacey E, Karuso P, Piggott AM. The chemical gymnastics of enterocin: evidence for stereodivergence in Nature. Org Biomol Chem 2020; 18:5879-5890. [PMID: 32672321 DOI: 10.1039/d0ob01099e] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/25/2024]
Abstract
Stereodivergence in Nature encapsulates both enzymatic (biosynthetic) and non-enzymatic (chemical) diversification of natural product scaffolds arising from a single biosynthetic pathway. Herein, we report a fascinating example of stereodivergence for the bacterial polyketide enterocin, which we observed to undergo a series of facile skeletal rearrangements in solution, leading to four distinct isomeric structures. The final distribution of the four isomers was found to be highly sensitive to the conditions used, including solvent, temperature and pH. In this study, we have investigated the kinetics of these isomeric conversions, and using a combination of DFT and thermochemical calculations, were able to establish a mechanism detailing a concerted rearrangement and an unusual "gymnastic" sequence of pseudo-chair-boat conformational interconversions. In addition to these kinetic and mechanistic studies, we also performed a semisynthetic study aimed at stabilising the enterocin scaffold. In total, seven analogues of enterocin were synthesised and investigated for their stability and in vitro activity against a panel of bacteria, fungi, plants and mammalian cells.
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Affiliation(s)
- Michael S Cowled
- Department of Molecular Sciences, Macquarie University, NSW 2109, Australia.
| | - Daniel Vuong
- Microbial Screening Technologies Pty. Ltd, Smithfield, NSW 2164, Australia
| | - Andrew Crombie
- Microbial Screening Technologies Pty. Ltd, Smithfield, NSW 2164, Australia
| | - Ernest Lacey
- Department of Molecular Sciences, Macquarie University, NSW 2109, Australia. and Microbial Screening Technologies Pty. Ltd, Smithfield, NSW 2164, Australia
| | - Peter Karuso
- Department of Molecular Sciences, Macquarie University, NSW 2109, Australia.
| | - Andrew M Piggott
- Department of Molecular Sciences, Macquarie University, NSW 2109, Australia.
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12
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Salim AA, Samarasekera K, Khalil ZG, Capon RJ. Exploring Natural Product Artifacts: The Polyketide Enterocin Warms to a Ballet of Isomers. Org Lett 2020; 22:4828-4832. [PMID: 32511935 DOI: 10.1021/acs.orglett.0c01629] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The polyketide enterocin is responsive to environmental stimuli, where mild heating promotes an equilibrium mixture of the isomeric acetals enterocins B and C, which subsequently undergo pseudo-chair-boat inversion to enterocin D. When exposed to aqueous base, enterocin is converted to the isomeric Michael acceptor enterocin F. These studies demonstrate that knowledge of environmental stimuli and associated artifacts is critical to understanding the chemical and ecological properties of enterocins and other classes of natural products.
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Affiliation(s)
- Angela A Salim
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Kaumadi Samarasekera
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Zeinab G Khalil
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Robert J Capon
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Queensland 4072, Australia
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13
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Abstract
A personal selection of 32 recent papers is presented covering various aspects of current developments in bioorganic chemistry and novel natural products such as melocochine A fromMelodinus cochinchinensis.
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