1
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Wang SQ, Qi WY, Yin XS, Shi BF. Formal total synthesis of (±)-7-deoxycylindrospermopsin and its 8- epi isomer. Org Chem Front 2021. [DOI: 10.1039/d1qo00381j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A concise formal synthesis of (±)-7-deoxycylindrospermopsin in 14 steps was reported.
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Affiliation(s)
- Si-Qing Wang
- Center of Chemistry for Frontier Technologies
- Department of Chemistry
- Zhejiang University
- Hangzhou 310027
- China
| | - Wei-Yi Qi
- Center of Chemistry for Frontier Technologies
- Department of Chemistry
- Zhejiang University
- Hangzhou 310027
- China
| | - Xue-Song Yin
- Center of Chemistry for Frontier Technologies
- Department of Chemistry
- Zhejiang University
- Hangzhou 310027
- China
| | - Bing-Feng Shi
- Center of Chemistry for Frontier Technologies
- Department of Chemistry
- Zhejiang University
- Hangzhou 310027
- China
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2
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Cartmell C, Evans DM, Elwood JM, Fituri HS, Murphy PJ, Caspari T, Poniedziałek B, Rzymski P. Synthetic analogues of cyanobacterial alkaloid cylindrospermopsin and their toxicological activity. Toxicol In Vitro 2017; 44:172-181. [DOI: 10.1016/j.tiv.2017.07.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Revised: 06/19/2017] [Accepted: 07/07/2017] [Indexed: 10/19/2022]
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3
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Schaubach S, Gebauer K, Ungeheuer F, Hoffmeister L, Ilg MK, Wirtz C, Fürstner A. A Two-Component Alkyne Metathesis Catalyst System with an Improved Substrate Scope and Functional Group Tolerance: Development and Applications to Natural Product Synthesis. Chemistry 2016; 22:8494-507. [DOI: 10.1002/chem.201601163] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Indexed: 01/02/2023]
Affiliation(s)
| | - Konrad Gebauer
- Max-Planck-Institut für Kohlenforschung; 45470 Mülheim/Ruhr Germany
| | - Felix Ungeheuer
- Max-Planck-Institut für Kohlenforschung; 45470 Mülheim/Ruhr Germany
| | | | - Marina K. Ilg
- Max-Planck-Institut für Kohlenforschung; 45470 Mülheim/Ruhr Germany
| | - Conny Wirtz
- Max-Planck-Institut für Kohlenforschung; 45470 Mülheim/Ruhr Germany
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung; 45470 Mülheim/Ruhr Germany
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4
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Proline catalyzed, one-pot three component Mannich reaction and sequential cyclization toward the synthesis of 2-substituted piperidine and pyrrolidine alkaloids. Tetrahedron Lett 2015. [DOI: 10.1016/j.tetlet.2015.03.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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5
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Shaitanova EN, Gerus II, Kukhar VP, Haufe G. Synthesis of enantiomerically pure 4-polyfluoromethyl-4-hydroxy-homoprolines by intramolecular cyclization of 6-amino-5-polyfluoromethyl-hex-2-enoic acids. J Fluor Chem 2014. [DOI: 10.1016/j.jfluchem.2014.01.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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6
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Evans DM, Horton PN, Hursthouse MB, Murphy PJ. Preparation of an ABC tricyclic model of the cylindrospermopsin alkaloids via a biomimetically inspired pathway. RSC Adv 2014. [DOI: 10.1039/c4ra03031a] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The protected guanidine18was convertedviaa 4-step sequence (Boc-deprotection, tethered Biginelli condensation, deallylation/decarboxylation and reduction) to give the tricyclic guanidines26and27, models of the tricyclic core of cylindrospermopsin1.
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7
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Cruz A, Padilla-Martínez II, García-Báez EV. A synthetic method to access symmetric and non-symmetric 2-(N,N'-disubstituted)guanidinebenzothiazoles. Molecules 2012; 17:10178-91. [PMID: 22922286 PMCID: PMC6268101 DOI: 10.3390/molecules170910178] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2012] [Revised: 08/14/2012] [Accepted: 08/15/2012] [Indexed: 11/16/2022] Open
Abstract
Symmetric and non-symmetric 2-(N-H, N-methyl, N-ethylenyl and N-aryl)guanidinebenzothiazoles were synthesized from the reaction of ammonia, methylamine, pyrrolidine and aniline with dimethyl benzo[d]thiazol-2-yl-carbonodithioimidate as intermediate. The products were characterized by ¹H-, ¹³C-NMR spectroscopy and three of them by X-ray diffraction analysis. HN-phenyl protons formed intramolecular hydrogen bonds that assist the stereochemistry of the second substituent, whereas the HN-alkyl protons were involved in intermolecular hydrogen bonding.
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Affiliation(s)
- Alejandro Cruz
- Departamento de Ciencias Básicas de la Unidad Profesional Interdisciplinaria de Biotecnología del IPN, Av. Acueducto s/n, Barrio la Laguna Ticomán, México, D.F. 07340, Mexico.
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8
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Bhat C, Tilve SG. Synthesis of (−)-hygrine, (−)-norhygrine, (−)-pseudohygroline and (−)-hygroline via Nef reaction. Tetrahedron Lett 2011. [DOI: 10.1016/j.tetlet.2011.09.118] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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9
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Shinohara R, Akimoto T, Iwamoto O, Hirokawa T, Yotsu-Yamashita M, Yamaoka K, Nagasawa K. Synthesis of skeletal analogues of saxitoxin derivatives and evaluation of their inhibitory activity on sodium ion channels Na(V)1.4 and Na(V)1.5. Chemistry 2011; 17:12144-52. [PMID: 21922571 DOI: 10.1002/chem.201101058] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2011] [Revised: 07/20/2011] [Indexed: 12/19/2022]
Abstract
Skeletal analogues of saxitoxin (STX) that possess a fused-type tricyclic ring system, designated FD-STX, were synthesized as candidate sodium ion channel modulators. Three kinds of FD-STX derivatives 4a-c with different substitution at C13 were synthesized, and their inhibitory activity on sodium ion channels was examined by means of cell-based assay. (-)-FD-STX (4a) and (-)-FD-dcSTX (4b), which showed moderate inhibitory activity, were further evaluated by the use of the patch-clamp method in cells that expressed Na(V)1.4 (a tetrodotoxin-sensitive sodium channel subtype) and Na(V)1.5 (a tetrodotoxin-resistant sodium channel subtype). These compounds showed moderate inhibitory activity towards Na(V)1.4, and weaker inhibitory activity towards Na(V)1.5. Uniquely, however, the inhibition of Na(V)1.5 by (-)-FD-dcSTX (4b) was "irreversible".
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Affiliation(s)
- Ryoko Shinohara
- Tokyo University of Agriculture and Technology, Department of Biotechnology and Life Science, Koganei, Tokyo 184-8588, Japan
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10
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Evans DM, Murphy PJ. A biomimetic approach to the cylindrospermopsin alkaloids. Chem Commun (Camb) 2011; 47:3225-6. [DOI: 10.1039/c0cc05034b] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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11
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Affiliation(s)
- Daniel M Evans
- School of Chemistry, Bangor University, Bangor, Gwynedd, UK
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12
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Davies SG, Fletcher AM, Roberts PM, Smith AD. Asymmetric synthesis of Sedum alkaloids via lithium amide conjugate addition. Tetrahedron 2009. [DOI: 10.1016/j.tet.2009.09.104] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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13
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14
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Hande SM, Kawai N, Uenishi J. An Efficient Synthesis of 2- and 2,6-Substituted Piperidines Using PdII-Catalyzed 1,3-Chirality Transfer Reaction. J Org Chem 2008; 74:244-53. [DOI: 10.1021/jo801926g] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Sudhir M. Hande
- Kyoto Pharmaceutical University, Misasagi, Yamashina, Kyoto 607-8412, Japan
| | - Nobuyuki Kawai
- Kyoto Pharmaceutical University, Misasagi, Yamashina, Kyoto 607-8412, Japan
| | - Jun’ichi Uenishi
- Kyoto Pharmaceutical University, Misasagi, Yamashina, Kyoto 607-8412, Japan
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15
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Fustero S, Jiménez D, Sanchez-Roselló M, del Pozo C. Microwave-Assisted Tandem Cross Metathesis Intramolecular Aza-Michael Reaction: An Easy Entry to Cyclic β-Amino Carbonyl Derivatives. J Am Chem Soc 2007; 129:6700-1. [PMID: 17480078 DOI: 10.1021/ja0709829] [Citation(s) in RCA: 121] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Santos Fustero
- Departamento de Química OrgAnica, Universidad de Valencia, E-46100 Burjassot, Spain
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16
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Shimokawa J, Ishiwata T, Shirai K, Koshino H, Tanatani A, Nakata T, Hashimoto Y, Nagasawa K. Total synthesis of (+)-batzelladine A and (-)-batzelladine D, and identification of their target protein. Chemistry 2006; 11:6878-88. [PMID: 16161173 DOI: 10.1002/chem.200500852] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Asymmetric total synthesis of batzelladine A (1) and batzelladine D (2) has been achieved. Our synthesis of batzelladines features 1) stereoselective construction of the cyclic guanidine system by means of successive 1,3-dipolar cycloaddition reaction and subsequent cyclization, 2) direct esterification of the bicyclic carboxylic acid 35 with the guanidine alcohol 8 or 59 to construct the whole carbon skeleton of batzelladines, and 3) one-step formation of the alpha,beta-unsaturated aldehyde 53 from the primary alcohol 47 with tetra-n-propylammoniumperruthenate (TPAP), providing an efficient route to the left-hand bicyclic guanidine alcohol of batzelladine A (1). With the synthetic compounds 1 and 2 in hand, their target protein was examined by using immobilized CD4 and gp120 affinity gels. The results indicated that batzelladines A (1) and D (2) bind specifically to CD4.
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Affiliation(s)
- Jun Shimokawa
- Institute of Molecular and Cellular Biosciences, University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan
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17
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18
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19
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Abdul-Ghan M, Khattab SN, El-Massry AM, El-Faham A, Amer A. A NOVEL AND DIRECT METHOD FOR THE PREPARATION OF 4-AMINO-1,1,3,3-TETRASUBSTTTUTED GUANIDINES AND OF [1,2,4]TRIAZOLO-FUSED HETEROCYCLIC DERIVATIVES. ORG PREP PROCED INT 2004. [DOI: 10.1080/00304940409355382] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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20
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21
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Total Synthesis of (±)-Cylindrospermopsin. ACTA ACUST UNITED AC 2004. [DOI: 10.1016/s1874-6004(04)80006-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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22
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Wabnitz TC, Spencer JB. A general, Brønsted acid-catalyzed hetero-Michael addition of nitrogen, oxygen, and sulfur nucleophiles. Org Lett 2003; 5:2141-4. [PMID: 12790549 DOI: 10.1021/ol034596h] [Citation(s) in RCA: 170] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
[reaction: see text] Strong Brønsted acids such as bis(trifluoromethanesulfon)imide catalyze the hetero-Michael addition of carbamates, alcohols, and thiols to alpha,beta-unsaturated ketones, alkylidene malonates, and acrylimides. Scope, reaction rates, and yields are superior to comparable Lewis acid-catalyzed processes.
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Affiliation(s)
- Tobias C Wabnitz
- Cambridge University Chemical Laboratory, Lensfield Road, Cambridge CB2 1EW, United Kingdom
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23
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Nagasawa K. [Total synthesis of marine cyclic guanidine compounds and development of novel guanidine type asymmetric organocatalysts]. YAKUGAKU ZASSHI 2003; 123:387-98. [PMID: 12822483 DOI: 10.1248/yakushi.123.387] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Crambescidins and batzelladines, novel marine guanidine alkaloids, have unique pentacyclic and tricyclic guanidine core structures, respectively. They display a considerable array of biological activity and not surprisingly have attracted considerable synthetic interest. The first total synthesis of crambescidin 359 (7) and stereoselective total synthesis of batzelladine D (11) were accomplished based on a successive 1,3-dipolar cycloaddition reaction strategy. During synthetic studies of 7, the absolute stereochemistry was revealed. Based on the structure of 7, the novel C2-symmetric pentacyclic guanidine compounds 69a-d were designed and synthesized as guanidine organocatalysts. The catalyst 69b works efficiently as an asymmetric catalyst of the alkylation reaction of the glycynate-benzophenone Schiff base 73, which gives 74 with 80-90% ee.
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Affiliation(s)
- Kazuo Nagasawa
- Institute of Molecular and Cellular Biosciences, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan.
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24
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Weintraub PM, Sabol JS, Kane JM, Borcherding DR. Recent advances in the synthesis of piperidones and piperidines. Tetrahedron 2003. [DOI: 10.1016/s0040-4020(03)00295-3] [Citation(s) in RCA: 320] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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25
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Humpage AR, Falconer IR. Oral toxicity of the cyanobacterial toxin cylindrospermopsin in male Swiss albino mice: determination of no observed adverse effect level for deriving a drinking water guideline value. ENVIRONMENTAL TOXICOLOGY 2003; 18:94-103. [PMID: 12635097 DOI: 10.1002/tox.10104] [Citation(s) in RCA: 156] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The cyanobacterial toxin cylindrospermopsin (CYN) is a frequent contaminant of freshwaters throughout the world, including those that are sources of drinking water. The first cases of human poisoning attributed to this toxin occurred from a treated drinking water supply in Queensland, Australia, in 1979. The toxin causes extensive damage to the liver, kidneys, spleen, heart, and other organs. It is known to be a potent protein synthesis inhibitor, but there is mounting evidence for genotoxicity and that it metabolizes to even more toxic forms. As part of a risk assessment process leading to a guideline for a safe drinking water level for this toxin, we performed a series of experiments to determine a no-observed-adverse-effect level (NOAEL) for this toxin. In the first trial male mice were exposed to CYN-containing cyanobacterial extract in their drinking water (0-657 microg CYN kg(-1) day(-1)) for 10 weeks. In the second trial mice received purified CYN by daily gavage (0-240 microg CYN kg(-1) day(-1)) for 11 weeks. Body and organ weights were recorded; urine, serum, and hematology analyses were performed; and histopathological examination of tissues was carried out. Body weights were significantly increased at low doses (30 and 60 microg kg(-1) day(-1)) and decreased at high doses (432 and 657 microg kg(-1) day(-1)). Liver and kidney weights were significantly increased at doses of 240 microg kg(-1) day(-1) and 60 microg kg(-1) day(-1), respectively. Serum bilirubin levels were significantly increased and bile acids significantly decreased at doses of 216 microg kg day(-1) and greater. Urine total protein was significantly decreased at doses above 60 microg kg(-1) day(-1). The kidney appeared to be the more sensitive organ to this toxin. If it is assumed that increased organ weights and changes in functional capacity are responses to an underlying toxic effect, then the NOAEL based on this data is 30 microg kg(-1) day(-1), which, with standard calculations and uncertainty factors, provides a proposed guideline safety value of 1 microg/L in drinking water.
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Affiliation(s)
- A R Humpage
- Australian Water Quality Centre, Cooperative Research Centre for Water Quality and Treatment, Private Bag 3, Salisbury, South Australia 5108.
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26
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Griffiths DJ, Saker ML. The Palm Island mystery disease 20 years on: a review of research on the cyanotoxin cylindrospermopsin. ENVIRONMENTAL TOXICOLOGY 2003; 18:78-93. [PMID: 12635096 DOI: 10.1002/tox.10103] [Citation(s) in RCA: 185] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Poisoning of humans resulting from consumption of water affected by the toxic cyanobacterium Cylindrospermopsis raciborskii was first reported almost 20 years ago from Palm Island, northern Queensland, Australia. Since that time a great deal has been learned about this organism and cylindrospermopsin (CYN), the toxin it produces. This article reviews the information now available to us. It summarizes aspects of the chemistry of the toxin-now known to be produced by some cyanobacterial species other than C. raciborskii-and its biosynthesis and chemical synthesis in vitro, as well as its detection and measurement by chemical and biological assay. Some of the factors affecting toxin production by cultured isolates of C. raciborskii are reviewed and the conditions that cause its release from the cells described. The occurrence of CYN in water bodies and the management strategies used to minimize the harmful effects of the toxin are outlined. These include a range of water-treatment practices now in place to remove CYN-producing organisms and/or to neutralize the toxin together with some management procedures that have been tried, with varying degrees of success, to prevent buildup of blooms of the offending organisms. Some of the public-health considerations arising from exposure to water supplies affected by CYN are summarized along with the risk factors and guidance values as they are currently applied. Among the more recent developments described are those that come from the application of molecular techniques for characterizing toxic and nontoxic strains and for exploring the genetic aspects of CYN production.
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Affiliation(s)
- Dilwyn J Griffiths
- School of Biological Sciences, James Cook University, Townsville 4811, Australia.
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27
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Stereoselective synthesis of tricyclic guanidine, the key component of the batzelladine alkaloids. Tetrahedron Lett 2002. [DOI: 10.1016/s0040-4039(02)01371-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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28
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Runnegar MT, Xie C, Snider BB, Wallace GA, Weinreb SM, Kuhlenkamp J. In vitro hepatotoxicity of the cyanobacterial alkaloid cylindrospermopsin and related synthetic analogues. Toxicol Sci 2002; 67:81-7. [PMID: 11961219 DOI: 10.1093/toxsci/67.1.81] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Cylindrospermopsin (CY), a sulfate ester of a tricyclic guanidine substituted with a hydroxymethyluracil, is a cyanobacterial toxin of increasing environmental import as it frequently occurs in drinking water reservoirs. As a toxin, CY mainly targets the liver but also involves other organs. In hepatocytes CY inhibits the synthesis of protein and of glutathione, leading to cell death. The total chemical synthesis of CY has recently been reported (Xie et al., 2000, J. Am. Chem. Soc. 22, 5017-5024). The synthesis has provided analogues of CY to study aspects of the relationship between chemical structure and activity that contribute to toxicity. Protein synthesis inhibition was measured in vitro using a rabbit reticulocyte system. Primary cultures of rat hepatocytes were used to determine the biological activity of CY and analogues in intact cells. Protein synthesis and cell glutathione levels were measured. We could distinguish between CY transport and biological activity by comparing the results in vitro to those in intact cells. The role of the sulfate group in CY toxicity was examined by comparing biological effects of CY with that of CY-DIOL (synthetic CY lacking the sulfate group). The sulfate group was found not to play a role in CY activity or in its uptake into cells, since there was no significant difference in biological activity in vitro or in cells between natural CY and CY-DIOL. The orientation of the hydroxyl group at C7 also had no impact on biological activity or transport of CY, since the C7 epimer of CY (EPI-CY) and the corresponding diol (EPI-DIOL) had activity similar to RAC-CY in vitro and in intact cells. AB-MODEL, the analogue lacking an intact C ring, and the methyl and hydroxyl groups of ring A could inhibit protein synthesis (but at concentrations 500-1000-fold higher than natural CY). Other structurally simpler synthetic analogues lacked biological activity.
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Affiliation(s)
- Maria T Runnegar
- USC Research Center for Liver Diseases, University of Southern California, Los Angeles, California 90033, USA.
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29
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Heintzelman GR, Fang WK, Keen SP, Wallace GA, Weinreb SM. Stereoselective total syntheses and reassignment of stereochemistry of the freshwater cyanobacterial hepatotoxins cylindrospermopsin and 7-epicylindrospermopsin. J Am Chem Soc 2002; 124:3939-45. [PMID: 11942831 DOI: 10.1021/ja020032h] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A stereoselective total synthesis of the structure 1 proposed for the freshwater cyanobacterial heptatotoxin cylindrospermopsin has been accomplished in approximately 30 operations starting from commercially available 4-methoxypyridine. Utilizing methodology developed by Comins, the tetrasubstituted piperidine A-ring unit of the hepatotoxin was efficiently constructed. The two remaining stereocenters in the natural product were then set by a stereospecific intramolecular N-sulfinylurea Diels-Alder cyclization/Grignard ring opening/allylic sulfoxide [2,3]-sigmatropic rearrangement sequence previously developed in these laboratories, leading to key intermediate 29. The stereochemical assignment of alcohol 29, which contains all six of the stereogenic centers of the natural product, was confirmed by an X-ray crystal structure determination of a derivative. Installation of the D-ring uracil moiety was effected by using our new methodology developed for this purpose, and construction of the C-ring guanidine completed the total synthesis of racemic structure 1. However, the (1)H NMR data for this compound do not match that of cylindrospermopsin, but instead agree with the data reported for 7-epicylindrospermopsin, a minor toxic metabolite that co-occurs with cylindrospermopsin. Therefore, we propose a revision of the stereochemical assignments of these natural products such that cylindrospermopsin is now represented as structure 2 and 7-epicylindrospermopsin is 1. This reassignment was further confirmed by Mitsunobu inversion of the C-7 alcohol 51 to epimer 52, and conversion of this compound to tetracyclic diol 57, which has previously been transformed to cylindrospermopsin (2).
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Affiliation(s)
- Geoffrey R Heintzelman
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
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30
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Bailén MA, Chinchilla R, Dodsworth DJ, Nájera C. O-Succinimidyl-1,3-dimethyl-1,3-trimethyleneuronium salts as efficient reagents in active ester synthesis. Tetrahedron Lett 2002. [DOI: 10.1016/s0040-4039(02)00090-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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31
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Heintzelman GR, Fang WK, Keen SP, Wallace GA, Weinreb SM. Stereoselective total synthesis of the cyanobacterial hepatotoxin 7-epicylindrospermopsin: revision of the stereochemistry of cylindrospermopsin. J Am Chem Soc 2001; 123:8851-3. [PMID: 11535093 DOI: 10.1021/ja011291u] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- G R Heintzelman
- Department of Chemistry The Pennsylvania State University University Park, Pennsylvania 16802, USA
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32
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Stereoselective synthesis of tricyclic guanidine systems: confirmation of the stereochemistry of batzelladine F left-hand tricyclic guanidine portion. Tetrahedron Lett 2001. [DOI: 10.1016/s0040-4039(01)00673-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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33
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Looper RE, Williams RM. Construction of the A-ring of cylindrospermopsin via an intramolecular oxazinone-N-oxide dipolar cycloaddition. Tetrahedron Lett 2001. [DOI: 10.1016/s0040-4039(00)01921-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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34
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del Fresno M, El-Faham A, Carpino LA, Royo M, Albericio F. Substituted guanidines: introducing diversity in combinatorial chemistry. Org Lett 2000; 2:3539-42. [PMID: 11073639 DOI: 10.1021/ol006322p] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The guanidine moiety is an important motif present in many biologically active compounds. Fully substituted guanidines are of key importance for the development of bioactive molecules. The present paper reports on an efficient procedure for the direct solid-phase conversion of amines to fully substituted guanidines under very mild conditions.
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Affiliation(s)
- M del Fresno
- Departament de Química Orgànica, Universitat de Barcelona, 08028 Barcelona, Spain
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