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Li G, Sun L, Dickschat JS, Guo Y. Klyflaccilins B‐T, Polyoxgenated Eunicellins from the Soft Coral
Klyxum flaccidum. European J Org Chem 2021. [DOI: 10.1002/ejoc.202001647] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Geng Li
- State Key Laboratory of Drug Research Shanghai Institute of Materia Medica Chinese Academy of Sciences 555 Zu Chong Zhi Road, Zhangjiang Hi-Tech Park 201203 Shanghai China
- Kekulé-Institute of Organic Chemistry and Biochemistry University of Bonn Gerhard-Domagk-Strasse 1 53121 Bonn Germany
- University of Chinese Academy of Sciences No. 19 A Yuquan Road Beijing 100049 China
| | - Li‐Li Sun
- State Key Laboratory of Drug Research Shanghai Institute of Materia Medica Chinese Academy of Sciences 555 Zu Chong Zhi Road, Zhangjiang Hi-Tech Park 201203 Shanghai China
- University of Chinese Academy of Sciences No. 19 A Yuquan Road Beijing 100049 China
| | - Jeroen S. Dickschat
- Kekulé-Institute of Organic Chemistry and Biochemistry University of Bonn Gerhard-Domagk-Strasse 1 53121 Bonn Germany
| | - Yue‐Wei Guo
- State Key Laboratory of Drug Research Shanghai Institute of Materia Medica Chinese Academy of Sciences 555 Zu Chong Zhi Road, Zhangjiang Hi-Tech Park 201203 Shanghai China
- University of Chinese Academy of Sciences No. 19 A Yuquan Road Beijing 100049 China
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Alcyonium Octocorals: Potential Source of Diverse Bioactive Terpenoids. Molecules 2019; 24:molecules24071370. [PMID: 30965598 PMCID: PMC6479912 DOI: 10.3390/molecules24071370] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 04/03/2019] [Accepted: 04/04/2019] [Indexed: 01/13/2023] Open
Abstract
Alcyonium corals are benthic animals, which live in different climatic areas, including temperate, Antarctic and sub-Antarctic waters. They were found to produce different chemical substances with molecular diversity and unique architectures. These metabolites embrace several terpenoidal classes with different functionalities. This wide array of structures supports the productivity of genus Alcyonium. Yet, majority of the reported compounds are still biologically unscreened and require substantial efforts to explore their importance. This review is an entryway to push forward the bio-investigation of this genus. It covers the era from the beginning of reporting metabolites from Alcyonium up to March 2019. Ninety-two metabolites are presented; forty-two sesquiterpenes, twenty-five diterpenes and twenty-five steroids have been reported from sixteen species.
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Clark JS, Delion L, Farrugia LJ. Synthesis of four diastereomers of sclerophytin F and structural reassignment of several sclerophytin natural products. Chemistry 2015; 21:4772-80. [PMID: 25663662 DOI: 10.1002/chem.201406051] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Indexed: 11/09/2022]
Abstract
Synthesis of the triol that has been proposed to be the marine natural product sclerophytin F has been completed along with the syntheses of three diastereomers. Comparison of the NMR spectroscopic data for all four compounds to the data reported for the natural product reveals that sclerophytin F is not the 3S diastereomer of sclerophytin A as proposed by Friedrich and Paquette. Re-analysis of the NMR spectroscopic data for known sclerophytin natural products and synthetic analogues leads to the conclusion that sclerophytins E and F are the same compound. This finding has allowed structural reassignment of several other cladiellin natural products.
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Affiliation(s)
- J Stephen Clark
- WestCHEM, School of Chemistry, Joseph Black Building, University of Glasgow, University Avenue, Glasgow G12 8QQ (UK).
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Clark JS, Delion L, Farrugia LJ. Total synthesis of the purported structure of sclerophytin F. Org Lett 2014; 16:4300-3. [PMID: 25068316 DOI: 10.1021/ol5020152] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The synthesis of the compound that has been proposed to be the natural product sclerophytin F has been completed from a known vinylogous carbonate. The synthetic strategy relied upon rearrangement of a catalytically generated ylide-like intermediate to produce an oxabicyclo[6.2.1]-5-undecen-9-one and an intermolecular Diels-Alder reaction to construct the complete tricyclic core found in the natural product. Comparison of the spectroscopic data for synthetic material to that reported for sclerophytin F shows that the natural product does not have the revised structure possessing the 3S configuration (*) proposed previously.
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Affiliation(s)
- J Stephen Clark
- WestCHEM, School of Chemistry, Joseph Black Building, University of Glasgow , University Avenue, Glasgow, G12 8QQ, United Kingdom
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Lai D, Liu D, Deng Z, van Ofwegen L, Proksch P, Lin W. Antifouling eunicellin-type diterpenoids from the gorgonian Astrogorgia sp. JOURNAL OF NATURAL PRODUCTS 2012; 75:1595-1602. [PMID: 22905736 DOI: 10.1021/np300404f] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Twelve new eunicellin-based diterpenoids, astrogorgins B-M (1-12), were isolated from a Chinese gorgonian Astrogorgia sp., together with ophirin, muricellin, astrogorgin, calicophirins A and B, and 14-deacetoxycalicophirin B. The structures of the new compounds were elucidated by extensive spectroscopic analysis and by comparison with data reported in the literature. Significant antifouling activity was observed for 14-deacetoxycalicophirin B against the larval settlement of the barnacle Balanus amphitrite at nontoxic concentrations with an EC(50) = 0.59 μg/mL, while the other analogues were effective within an EC(50) range of 5.14-17.8 μg/mL.
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Affiliation(s)
- Daowan Lai
- State Key Laboratory of Natural and Biomimetic Drugs, Peking University, Beijing 100191, People's Republic of China
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Chen BW, Huang CY, Wen ZH, Su JH, Wang WH, Sung PJ, Wu YC, Sheu JH. Klysimplexins U–X, Eunicellin-Based Diterpenoids from the Cultured Soft CoralKlyxum simplex. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2011. [DOI: 10.1246/bcsj.20110156] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Tai CY, Chen YH, Hwang TL, Fang LS, Wang WH, Liu MC, Su JH, Wu YC, Sung PJ. Cladielloides C and D: Novel Eunicellin-Based Diterpenoids from an Indonesian OctocoralCladiellasp. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2011. [DOI: 10.1246/bcsj.20100348] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Chen BW, Chao CH, Su JH, Tsai CW, Wang WH, Wen ZH, Huang CY, Sung PJ, Wu YC, Sheu JH. Klysimplexins I-T, eunicellin-based diterpenoids from the cultured soft coral Klyxum simplex. Org Biomol Chem 2010; 9:834-44. [PMID: 21109855 DOI: 10.1039/c0ob00351d] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
New eunicellin-base diterpenoids, klysimplexins I-T (1-12), were isolated from a cultured soft coral Klyxum simplex. Their structures were elucidated by spectroscopic methods, particularly in 1D and 2D NMR experiments. The absolute stereochemistry of 4 was determined by Mosher's method. Compounds 9 and 12 have been shown to exhibit cytotoxicity toward a limited panel of cancer cell lines. Compounds 2-6, 10 and 11 were found to display significant in vitro anti-inflammatory activity in LPS-stimulated RAW264.7 macrophage cells by inhibiting the expression of the iNOS protein. Compounds 10 and 11 also could effectively reduce the level of COX-2 protein.
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Affiliation(s)
- Bo-Wei Chen
- Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung 804, Taiwan
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Hassan HM, Khanfar MA, Elnagar AY, Mohammed R, Shaala LA, Youssef DTA, Hifnawy MS, El Sayed KA. Pachycladins A-E, prostate cancer invasion and migration inhibitory Eunicellin-based diterpenoids from the red sea soft coral Cladiella pachyclados. JOURNAL OF NATURAL PRODUCTS 2010; 73:848-853. [PMID: 20420415 DOI: 10.1021/np900787p] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Alcyonaria species are among the important marine invertebrate classes that produce a wealth of chemically diverse bioactive diterpenes. Examples of these are the potent microtubule disruptor sarcodictyins and eleutherobin. The genus Cladiella has proven to be a rich source of cytotoxic eunicellin-based diterpenoids. Five new eunicellin diterpenes, pachycladins A-E (1-5), were isolated from the Red Sea soft coral Cladiella pachyclados. The known sclerophytin A Cladiellisin, 3-acetylcladiellisin, 3,6-diacetylcladiellisin, (+)-polyanthelin A, klysimplexin G, klysimplexin E, sclerophytin F methyl ether, (6Z)-cladiellin (cladiella-6Z,11(17)-dien-3-ol), sclerophytin B, and patagonicol were also identified. The structures of the isolated compounds were elucidated by extensive interpretation of their spectroscopic data. These compounds were evaluated for their ability to inhibit growth, proliferation, invasion, and migration of the prostate cancer cells PC-3. Some of the new metabolites exhibited significant anti-invasive activity.
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Affiliation(s)
- Hossam M Hassan
- Department of Basic Pharmaceutical Sciences, College of Pharmacy, University of Louisiana at Monroe, Monroe, Louisiana 71201, USA
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Corminboeuf O, Overman LE, Pennington LD. A unified strategy for enantioselective total synthesis of cladiellin and briarellin diterpenes: total synthesis of briarellins E and F and the putative structure of alcyonin and revision of its structure assignment. J Org Chem 2009; 74:5458-70. [PMID: 19534538 PMCID: PMC2744073 DOI: 10.1021/jo9010156] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Enantioselective total syntheses of briarellin E (12) and briarellin F (13), as well as the structure originally proposed for the cladiellin diterpene alcyonin (10), have been realized. Comparison of the spectral data for synthetic 10, natural alcyonin, cladiellisin (33), and cladiellaperoxide (34), as well as chemical transformations of 10 and natural alcyonin, suggest that the structure of this coral metabolite is allylic peroxide 11. The unified approach detailed herein can be used to access both C4-deoxygenated and C4-oxygenated cladiellins and briarellins. The central step in these syntheses is acid-promoted condensation of (Z)-alpha,beta-unsaturated aldehydes 17 with cyclohexadienyl diols 18 to form intermediates 16 incorporating the hexahydroisobenzofuran core and five stereocenters of these marine diterpenes (Scheme 1 ).
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Affiliation(s)
| | - Larry E. Overman
- Department of Chemistry, 1102 Natural Sciences II, University of California, Irvine, California 92697-2025
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Chen BW, Wu YC, Chiang MY, Su JH, Wang WH, Fan TY, Sheu JH. Eunicellin-based diterpenoids from the cultured soft coral Klyxum simplex. Tetrahedron 2009. [DOI: 10.1016/j.tet.2009.06.047] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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12
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Chen WC, Sheu JH, Fang LS, Hu WP, Sung PJ. 3Alpha,7alpha,12alpha-triacetoxy-5beta-cholanic acid, a steroid from the Formosan soft coral Alcyonium sp. (Alcyoniidae). Nat Prod Res 2006; 20:748-53. [PMID: 16753908 DOI: 10.1080/14786410500463379] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Chemical investigation of the organic extract of a soft coral belonging to the genus Alcyonium furnished a steroid, 3alpha,7alpha,12alpha-triacetoxy-5beta-cholanic acid (1). The structure of steroid 1 was assigned on the basis of spectroscopic evidence, particularly in 1D and 2D NMR experiments. The configuration of steroid 1 was further supported by molecular mechanics calculations.
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Affiliation(s)
- Wen-Chen Chen
- National Museum of Marine Biology and Aquarium, Taiwan, R.O.C
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Abstract
The structural designation A originally made by Sharma and Alam to sclerophytin A was considered to be ambiguous and so notably strained relative to B that the latter was targeted for de novo synthesis (Scheme 1). Our two successful routes began with (5S)-(d-menthyloxy)-2(5H)-furanone and involved the application of cycloaddition, Claisen ring expansion, transannular oxymercuration, and 1,2-carbonyl transposition tactics to arrive at B. It was immediately apparent from polarity considerations and spectroscopic data that the antileukemic marine metabolite in question was in need of more deep-seated structural revision. Following close re-examination of an acquired authentic sample by advanced NMR techniques, the strong inference was made that sclerophytin A actually lacked a second oxygen bridge and was in reality the triol C. This conclusion was unequivocally confirmed by diverting an advanced intermediate generated earlier into a short sequence beginning with regiocontrolled dihydroxylation and terminating with configurational inversion at the secondary carbinol center. The status of other members of this series is also presented.
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Affiliation(s)
- L A Paquette
- Evans Chemical Laboratories, The Ohio State University, Columbus 43210, USA.
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Friedrich D, Paquette LA. Structural and stereochemical reassessment of sclerophytin-type diterpenes. JOURNAL OF NATURAL PRODUCTS 2002; 65:126-130. [PMID: 11858742 DOI: 10.1021/np0103822] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
A complete reassessment of the structural assignments of the sclerophytin diterpenes is provided.
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Affiliation(s)
- Dirk Friedrich
- Evans Chemical Laboratories, The Ohio State University, Columbus, Ohio 43210, USA
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Bernardelli P, Moradei OM, Friedrich D, Yang J, Gallou F, Dyck BP, Doskotch RW, Lange T, Paquette LA. Total asymmetric synthesis of the putative structure of the cytotoxic diterpenoid (-)-sclerophytin a and of the authentic natural sclerophytins A and B. J Am Chem Soc 2001; 123:9021-32. [PMID: 11552810 DOI: 10.1021/ja011285y] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
An enantioselective synthetic route to the thermodynamically most stable diastereomer of the structure assigned to sclerophytin A (5) has been realized. The required tricyclic ketone 33 was prepared by sequential Tebbe-Claisen rearrangement of lactones 29 and 30, which originated from the Diels-Alder cycloaddition of Danishefsky's diene to (5S)-5-(d-menthyloxy)-2(5H)-furanone (14). An allyl and a cyano group were introduced into the resulting adduct by means of stereocontrolled allylindation under aqueous Barbier-like conditions and by way of cyanotrimethylsilane, respectively. Following stereocontrolled nucleophilic addition of a methyl group to 33, ring A was elaborated by formation of the silyl enol ether, ytterbium triflate-catalyzed condensation with formaldehyde, O-silylation, and Cu(I)-promoted 1,4-addition of isopropylmagnesium chloride. The superfluous ketone carbonyl was subsequently removed and the second ether bridge introduced by means of oxymercuration chemistry. Only then was the exocyclic methylene group unmasked via elimination. An alternative approach to the alpha-carbinol diastereomer proceeds by initial alpha-oxygenation of 37 and ensuing 1,2-carbonyl transposition. Neither this series of steps nor the Wittig olefination to follow induced epimerization at C10. Through deployment of oxymercuration chemistry, it was again possible to elaborate the dual oxygen-bridge network of the target ring system. Oxidation of the organomercurial products with O(2) in the presence of sodium borohydride furnished 72, which was readily separated from its isomer 73 after oxidation to 61. Hydride attack on this ketone proceeded with high selectivity from the beta-direction to deliver (-)-60. Comparison of the high-field (1)H and (13)C NMR properties and polarity of synthetic 5 with natural material required that structural revision be made. Following a complete spectral reassessment of the structural assignments to many sclerophytin diterpenes, a general approach to sclerophytin A, three diastereomers thereof, and of sclerophytin B was devised. The presence of two oxygen bridges as originally formulated was thereby ruled out, and absolute configurations were properly determined. Key elements of the strategy include dihydroxylation of a medium-ring double bond, oxidation of the secondary hydroxyl in the two resulting diols, unmasking of an exocyclic methylene group at C-11, and stereocontrolled 1,2-reduction of the alpha-hydroxy ketone functionality made available earlier.
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Affiliation(s)
- P Bernardelli
- Department of Chemistry, The Ohio State University, Columbus, OH 43210, USA
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Wang GH, Sheu JH, Chiang MY, Lee TJ. Pachyclavulariaenones A–C, three novel diterpenoids from the soft coral Pachyclavularia violacea. Tetrahedron Lett 2001. [DOI: 10.1016/s0040-4039(01)00180-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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17
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Paquette LA, Moradei OM, Bernardelli P, Lange T. Synthesis of the alleged structure of sclerophytin A. The setting of two oxygen bridges within the fused cyclodecanol B ring is not Nature's Way. Org Lett 2000; 2:1875-8. [PMID: 10891180 DOI: 10.1021/ol000083o] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
[reaction: see text] The structure attributed to sclerophytin A, a cytotoxic soft coral metabolite, was synthesized in an enantioselective manner from (5S)-5-(d-menthyloxy)-2(5H)-furanone. The spectral properties and polarity of the synthetic product require that the structural assignment to the natural material be revised.
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Affiliation(s)
- L A Paquette
- Evans Chemical Laboratories, The Ohio State University, Columbus, Ohio 43210, USA.
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Abstract
[structure: see text] Spectroscopic reevaluation of sclerophytin B, the acetate of sclerophytin A, has demonstrated unequivocally that these coral metabolites are not composed of two ether bridges.
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Affiliation(s)
- D Friedrich
- Department of Chemistry, Medicinal Chemistry, and Pharmacognosy, The Ohio State University, Columbus, Ohio 43210, USA
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