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Study of the Oxidative Cleavage Proposed in the Biogenesis of Transtaganolides/Basiliolides: Pyran-2-one Aromaticity-Mediated Regioselective Control and Biogenetic Implications. European J Org Chem 2020. [DOI: 10.1002/ejoc.201901894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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2
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15-Hydroxygermacranolides as Sources of Structural Diversity: Synthesis of Sesquiterpene Lactones by Cyclization and Rearrangement Reactions. Experimental and DFT Study. J Org Chem 2018; 83:5480-5495. [PMID: 29694044 DOI: 10.1021/acs.joc.8b00407] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
A study on the electrophile-induced rearrangement of two 15-hydroxygermacranolides, salonitenolide and artemisiifolin, was carried out. These compounds underwent electrophilic intramolecular cyclizations or acid-mediated rearrangements to give sesquiterpene lactones with different skeletons such as eudesmanolides, guaianolides, amorphanolides, or other germacranolides. The cyclization that gives guaianolides can be considered a biomimetic route to this type of sesquiterpene lactones. The use of acetone as a solvent changes the reactivity of the two starting germacranolides to the acid catalysts, with a 4,15-diol acetonide being the main product obtained. The δ-amorphenolide obtained by intramolecular cyclization of this acetonide is a valuable intermediate for accessing the antimalarials artemisinin and its derivatives. Mechanistic proposals for the transformations are raised, and to provide support them, quantum chemical calculations [DFT B3LYP/6-31+G(d,p) level] were undertaken.
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TiCl4/Et3N-Mediated Condensation of Acetate and Formate Esters: Direct Access to β-Alkoxy- and β-Aryloxyacrylates. Org Lett 2016; 18:6344-6347. [DOI: 10.1021/acs.orglett.6b03233] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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4
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Acyloxylation of 1,4-Dioxanes and 1,4-Dithianes Catalyzed by a Copper–Iron Mixed Oxide. J Org Chem 2015; 80:6814-21. [DOI: 10.1021/acs.joc.5b01043] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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5
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Optimization by Response Surface Methodology (RSM) of the Kharasch–Sosnovsky Oxidation of Valencene. Org Process Res Dev 2014. [DOI: 10.1021/op5002462] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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6
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Acyloxylation of Cyclic Enones: Synthesis of Densely Oxygenated Guaianolides. J Org Chem 2014; 79:6501-9. [DOI: 10.1021/jo500915r] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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7
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Abstract
A strategy for the allylic oxidation of cyclic alkenes with a copper-aluminum mixed oxide as catalyst is presented. The reaction involves the treatment of an alkene with a carboxylic acid employing tert-butyl hydroperoxide as the oxidant. In all cases, the corresponding allylic esters are obtained. When L-proline is employed, the allylic alcohol or ketone is obtained. The oxidation of cyclohexene and valencene has been optimized by design of experiments (DoE) statistical methodology.
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DoE (Design of Experiments) Assisted Allylic Hydroxylation of Enones Catalysed by a Copper-Aluminium Mixed Oxide. European J Org Chem 2013. [DOI: 10.1002/ejoc.201301145] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Recent Advances in the Synthesis of Sesquiterpenolides from Umbelliferae. Nat Prod Commun 2011. [DOI: 10.1177/1934578x1100600409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
A review of our latest developments in the synthesis of sesquiterpenolides isolated from plants of the Umbelliferae family is presented.
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Recent advances in the synthesis of sesquiterpenolides from Umbelliferae. Nat Prod Commun 2011; 6:491-496. [PMID: 21560761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023] Open
Abstract
A review of our latest developments in the synthesis of sesquiterpenolides isolated from plants of the Umbelliferae family is presented.
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A phenylpropanoid, a slovenolide, two sulphur-containing germacranes and Ca2+-ATPase inhibitors from Thapsia villosa. PLANTA MEDICA 2010; 76:284-290. [PMID: 19708003 DOI: 10.1055/s-0029-1186056] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
A phenylpropanoid 1, a slovenolide 2, and two germacranes bearing a methylthiopropenoate moiety, 3 and 4, along with twenty known metabolites have been isolated from the roots of Thapsia villosa var. villosa L. The structures of two known phenylpropanoids 5 and 6 have been corrected. Compounds 7 and 8 showed activity as potential inhibitors of the sarco- and endoplasmic Ca(2+)-dependent ATPases (SERCA) pump. Compounds 9, 10 and 11 increased significantly the cytoplasmic free calcium concentration ([Ca(2+)](c)) in human platelets in a concentration-dependent manner.
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An easy access to bioactive 13-hydroxylated and 11,13-dihydroxylated sesquiterpene lactones (SLs) through Michael addition of a nucleophilic hydroxyl group. Tetrahedron 2008. [DOI: 10.1016/j.tet.2008.09.024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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14
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A pyran-2-one and four meroterpenoids from Thapsia transtagana and their implication in the biosynthesis of transtaganolides. PHYTOCHEMISTRY 2007; 68:2480-6. [PMID: 17669447 DOI: 10.1016/j.phytochem.2007.06.023] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2007] [Revised: 06/15/2007] [Accepted: 06/16/2007] [Indexed: 05/06/2023]
Abstract
Four meroterpenoids (3a, 3b, 4 and 5), a prenylated pyran-2-one (2) along with the known compounds 7-O-geranylscopoletin (1), and thapsitranstagin (6) have been isolated from the roots of Thapsia transtagana. The presence of 1 and 2 supports the biogenetic hypothesis that transtaganolides, a group of bioactive metabolites, are meroterpenoids which come from an O-prenylated coumarin via successive pericyclic reactions.
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Toward the synthesis of thapsigargin: enantioselective synthesis of 7,11-dihydroxyguaianolides. Org Lett 2007; 8:2879-82. [PMID: 16774280 DOI: 10.1021/ol061024z] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
[reaction: see text] The enantioselective synthesis of a 7,11-dihydroxyguaianolide bearing the stereochemistry present in thapsigargin, a potent and selective inhibitor of the Ca(2+) SERCA-ATPase pumps, is described. Starting from (+)-dihydrocarvone, the synthesis presents two key steps. The first one involves the photochemical rearrangement of a gamma,delta-unsaturated ketone eudesmane into the corresponding guaiane. The second step consists of the regioselective oxidation of an unprotected tetrahydroxylated ketone to provide a dihydroxylactone with the required stereochemistry.
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Sesquiterpenes from Thapsia nitida var. meridionalis and Thapsia nitida var. nitida. JOURNAL OF NATURAL PRODUCTS 2006; 69:1566-71. [PMID: 17125222 DOI: 10.1021/np0603065] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Nine new eudesmanolides (1-9), two new guaianolides (12 and 13), and a new germacrane (10), along with a previously reported guaianolide (11), have been isolated from the roots of Thapsia nitida var. meridionalis. Thapsia nitida var. nitida also afforded compound 13 along with a new guaianolide (14). The structure of 13 was confirmed by X-ray crystallographic analysis. Compounds 1, 2, and 11-14 have been tested as potential inhibitors of the sarco- and endoplasmic Ca2+-dependent ATPases (SERCA) pump. None of them showed significant activities.
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Phenylpropanoids from Thapsia transtagana. PHYTOCHEMISTRY 2006; 67:800-4. [PMID: 16540132 DOI: 10.1016/j.phytochem.2006.01.032] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2005] [Revised: 01/25/2006] [Accepted: 01/27/2006] [Indexed: 05/07/2023]
Abstract
Five phenylpropanoids have been isolated from the roots of Thapsia transtagana. Their structures have been elucidated by spectroscopic means.
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Abstract
Four novel and unusual C-19 compounds from Thapsia transtagana, named transtaganolides A-D, have been isolated. Their structures were established by physical methods, including X-ray analysis of transtaganolides A and B. This is the first time that a 7-methoxy-4,5-dihydro-3H-oxepin-2-one ring has been found in a natural product. [structure: see text]
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Terpene synthesis. 1. Chemical transformation of deacylsubexpinnatin into the natural oxetane lactone subexpinnatin C. J Org Chem 2002. [DOI: 10.1021/jo00391a028] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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23
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Regioselective cyclization of alpha,omega-alkynoic acids catalysed by TpRu complexes: synthesis of endocyclic enol lactones [Tp = hydrotris(pyrazolyl)borate]. Chem Commun (Camb) 2001:2324-5. [PMID: 12240057 DOI: 10.1039/b106647c] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The sigma-enynyl complex [TpRu(C(Ph)=C(Ph)C identical to CPh)(P-MeiPr2)] efficiently catalyses the regioselective cyclization of alpha,omega-alkynoic acids to yield endocyclic enol lactones having ring size up to 12 atoms.
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Synthesis of (+/-)-11alpha-hydroxy-3-oxo-6alphaH,7alphaH, 10betaMe-eudesman-1,2-4,5-dien-6,12-olide. JOURNAL OF NATURAL PRODUCTS 2000; 63:934-938. [PMID: 10924168 DOI: 10.1021/np990537u] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The synthesis of (+/-)-11alpha-hydroxy-3-oxo-6alphaH,7alphaH, 10betaMe-eudesman-1,2-4,5-dien-6,12-olide (1), previously isolated from Melanoselinum decipiens, is described, and its structure has been corrected.
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Studies on the Stereostructure of Eudesmanolides from Umbelliferae: Total Synthesis of (+)-Decipienin A. Tetrahedron 2000. [DOI: 10.1016/s0040-4020(00)00240-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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27
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Enantioselective synthesis of α-hydroxyacids through oxidation of terminal alkenes with AD-mix/TEMPO. Tetrahedron Lett 2000. [DOI: 10.1016/s0040-4039(00)00352-x] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Studies on the stereostructure of eudesmanolides from Umbelliferae: synthesis of 11β-angeloyloxy-α-santonin. Tetrahedron 1994. [DOI: 10.1016/s0040-4020(01)80700-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Abstract
The leaves of PILOCARPUS GOUDOTIANUS afforded in addition to eight known coumarins three new ones, donatin, alloxanthoxyletol, and (+)-elisin. The structures were elucidated on the basis of spectroscopic evidence and chemical derivatives.
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13 C NMR of coumarins. III-Simple coumarins. MAGNETIC RESONANCE IN CHEMISTRY : MRC 1989; 27:892-894. [PMID: 34034431 DOI: 10.1002/mrc.1260270913] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/1989] [Accepted: 03/10/1989] [Indexed: 06/12/2023]
Abstract
13 C NMR data for several simple coumarins are reported. The γsyn effect of a 5-methoxy substituent on the C-4 chemical shift was observed and measured. The effects of an 8-iodo substituent on the chemical shifts of the carbons of the coumarinic skeleton are discussed.
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39
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Sigmatropic Rearrangement in Synthesis of C-8 Prenylated 3-(1',1'-Dimethylallyl)coumarins: 3-(1',1'-Dimethylallyl)seselin. HETEROCYCLES 1989. [DOI: 10.3987/com-89-4710] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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40
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Configuration of 1,10-epoxyguaianolides: stereochemistry of 1,10-epoxy-8α-hydroxyachillin. ACTA ACUST UNITED AC 1987. [DOI: 10.1039/p19870001641] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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42
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43
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Chemistry of the compositae. Part 38. Structure and absolute configuration of gallicin, a new germacranolide from Artemisia. ACTA ACUST UNITED AC 1978. [DOI: 10.1039/p19780001243] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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44
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The chemistry of the compositae. Part XXXI. Absolute configuration of the sesquiterpene lactones centaurepensin (chlorohyssopifolin A), acroptilin (chlorohyssopifolin C), and repin. ACTA ACUST UNITED AC 1976. [DOI: 10.1039/p19760001663] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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