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Abstract
Nitroxides, also known as nitroxyl radicals, are long-lived or stable radicals with the general structure R1R2N-O•. The spin distribution over the nitroxide N and O atoms contributes to the thermodynamic stability of these radicals. The presence of bulky N-substituents R1 and R2 prevents nitroxide radical dimerization, ensuring their kinetic stability. Despite their reactivity toward various transient C radicals, some nitroxides can be easily stored under air at room temperature. Furthermore, nitroxides can be oxidized to oxoammonium salts (R1R2N═O+) or reduced to anions (R1R2N-O-), enabling them to act as valuable oxidants or reductants depending on their oxidation state. Therefore, they exhibit interesting reactivity across all three oxidation states. Due to these fascinating properties, nitroxides find extensive applications in diverse fields such as biochemistry, medicinal chemistry, materials science, and organic synthesis. This review focuses on the versatile applications of nitroxides in organic synthesis. For their use in other important fields, we will refer to several review articles. The introductory part provides a brief overview of the history of nitroxide chemistry. Subsequently, the key methods for preparing nitroxides are discussed, followed by an examination of their structural diversity and physical properties. The main portion of this review is dedicated to oxidation reactions, wherein parent nitroxides or their corresponding oxoammonium salts serve as active species. It will be demonstrated that various functional groups (such as alcohols, amines, enolates, and alkanes among others) can be efficiently oxidized. These oxidations can be carried out using nitroxides as catalysts in combination with various stoichiometric terminal oxidants. By reducing nitroxides to their corresponding anions, they become effective reducing reagents with intriguing applications in organic synthesis. Nitroxides possess the ability to selectively react with transient radicals, making them useful for terminating radical cascade reactions by forming alkoxyamines. Depending on their structure, alkoxyamines exhibit weak C-O bonds, allowing for the thermal generation of C radicals through reversible C-O bond cleavage. Such thermally generated C radicals can participate in various radical transformations, as discussed toward the end of this review. Furthermore, the application of this strategy in natural product synthesis will be presented.
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Affiliation(s)
- Dirk Leifert
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität, Corrensstrasse 40, 48149 Münster, Germany
| | - Armido Studer
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität, Corrensstrasse 40, 48149 Münster, Germany
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Brusentseva OI, Kharitonov YV, Dolgikh MP, Tolstikova TG, Shul’ts EE. Synthesis and Analgesic Activity Assessment of Furanolabdanoid Conjugates with Glucuronic Acid. Chem Nat Compd 2020. [DOI: 10.1007/s10600-020-03119-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Beejapur HA, Zhang Q, Hu K, Zhu L, Wang J, Ye Z. TEMPO in Chemical Transformations: From Homogeneous to Heterogeneous. ACS Catal 2019. [DOI: 10.1021/acscatal.8b05001] [Citation(s) in RCA: 88] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Hazi Ahmad Beejapur
- State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology, Zhejiang Province Key Laboratory of Biofuel, Biodiesel Laboratory of China Petroleum and Chemical Industry Federation, College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, P. R. China
| | - Qi Zhang
- State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology, Zhejiang Province Key Laboratory of Biofuel, Biodiesel Laboratory of China Petroleum and Chemical Industry Federation, College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, P. R. China
| | - Kecheng Hu
- State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology, Zhejiang Province Key Laboratory of Biofuel, Biodiesel Laboratory of China Petroleum and Chemical Industry Federation, College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, P. R. China
| | - Li Zhu
- State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology, Zhejiang Province Key Laboratory of Biofuel, Biodiesel Laboratory of China Petroleum and Chemical Industry Federation, College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, P. R. China
| | - Jianli Wang
- State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology, Zhejiang Province Key Laboratory of Biofuel, Biodiesel Laboratory of China Petroleum and Chemical Industry Federation, College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, P. R. China
| | - Zhibin Ye
- Department of Chemical and Materials Engineering, Concordia University, Montreal, Quebec H3G 1M8, Canada
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Dimakos V, Taylor MS. Site-Selective Functionalization of Hydroxyl Groups in Carbohydrate Derivatives. Chem Rev 2018; 118:11457-11517. [DOI: 10.1021/acs.chemrev.8b00442] [Citation(s) in RCA: 148] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Victoria Dimakos
- Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, ON M5S 3H6, Canada
| | - Mark S. Taylor
- Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, ON M5S 3H6, Canada
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Targel T, Ramesh P, Portnoy M. Domino Two-Step Oxidation of β-Alkoxy Alcohols to Hemiacetal Esters: Linking a Stoichiometric Step to an Organocatalytic Step with a Common Organic Oxidant. European J Org Chem 2018. [DOI: 10.1002/ejoc.201800380] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Tom Targel
- School of Chemistry; Tel Aviv University; 6997801 Tel Aviv Israel
| | - Palakuri Ramesh
- School of Chemistry; Tel Aviv University; 6997801 Tel Aviv Israel
| | - Moshe Portnoy
- School of Chemistry; Tel Aviv University; 6997801 Tel Aviv Israel
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Tiwari V, Badavath VN, Singh AK, Kandasamy J. A highly efficient TEMPO mediated oxidation of sugar primary alcohols into uronic acids using 1-chloro-1,2-benziodoxol-3(1H)-one at room temperature. Tetrahedron Lett 2018. [DOI: 10.1016/j.tetlet.2018.05.021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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Rajput J, Hotha S, Vangala M. AuBr 3-catalyzed azidation of per- O-acetylated and per- O-benzoylated sugars. Beilstein J Org Chem 2018; 14:682-687. [PMID: 29623131 PMCID: PMC5870170 DOI: 10.3762/bjoc.14.56] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2017] [Accepted: 03/05/2018] [Indexed: 12/23/2022] Open
Abstract
Herein we report, for the first time, the successful anomeric azidation of per-O-acetylated and per-O-benzoylated sugars by catalytic amounts of oxophilic AuBr3 in good to excellent yields. The method is applicable to a wide range of easily accessible per-O-acetylated and per-O-benzoylated sugars. While reaction with per-O-acetylated and per-O-benzoylated monosaccharides was complete within 1-3 h at room temperature, the per-O-benzoylated disaccharides needed 2-3 h of heating at 55 °C.
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Affiliation(s)
- Jayashree Rajput
- Department of Chemistry, Indian Institute of Science Education and Research, Pune 411 008, India
| | - Srinivas Hotha
- Department of Chemistry, Indian Institute of Science Education and Research, Pune 411 008, India
| | - Madhuri Vangala
- Department of Chemistry, Indian Institute of Science Education and Research, Pune 411 008, India
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Methyl tetra-O-acetyl-α-D-glucopyranuronate: crystal structure and influence on the crystallisation of the β anomer. Carbohydr Res 2016; 425:35-9. [PMID: 27031190 DOI: 10.1016/j.carres.2016.01.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Revised: 01/14/2016] [Accepted: 01/21/2016] [Indexed: 11/22/2022]
Abstract
Methyl tetra-O-acetyl-β-D-glucopyranuronate (1) and methyl tetra-O-acetyl-α-D-glucopyranuronate (3) were isolated as crystalline solids and their crystal structures were obtained. That of the β anomer (1) was the same as that reported by Root et al., while anomer (3) was found to crystallise in the orthorhombic space group P212121 with two independent molecules in the asymmetric unit. No other crystal forms were found for either compound upon recrystallisation from a range of solvents. The α anomer (3) was found to be an impurity in initially precipitated batches of β-anomer (1) in quantities <3%; however, it was possible to remove the α impurity either by recrystallisation or by efficient washing, i.e. the α anomer is not incorporated inside the β anomer crystals. The β anomer (1) was found to grow as prisms or needles elongated in the a crystallographic direction in the absence of the α impurity, while the presence of the α anomer (3) enhanced this elongation.
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Cara CJ, Skropeta D. Glycosylation and functionalization of native amino acids with azido uronic acids. Tetrahedron 2015. [DOI: 10.1016/j.tet.2015.10.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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10
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Tabor RF, Pottage MJ, Garvey CJ, Wilkinson BL. Light-induced structural evolution of photoswitchable carbohydrate-based surfactant micelles. Chem Commun (Camb) 2015; 51:5509-12. [DOI: 10.1039/c4cc07657e] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
We report the light-induced structural evolution of photoswitchable carbohydrate-based surfactant micelles using time-resolved small-angle neutron scattering (TR-SANS), monitoring the structural changes in micellisation in situ over time and demonstrating for the first time the course and implications of this process.
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11
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Taylor MS. Catalyst-Controlled, Regioselective Reactions of Carbohydrate Derivatives. SITE-SELECTIVE CATALYSIS 2015; 372:125-55. [DOI: 10.1007/128_2015_656] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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12
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Salamone S, Boisbrun M, Didierjean C, Chapleur Y. From d-glucuronic acid to l-iduronic acid derivatives via a radical tandem decarboxylation–cyclization. Carbohydr Res 2014; 386:99-105. [DOI: 10.1016/j.carres.2014.01.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Revised: 12/30/2013] [Accepted: 01/08/2014] [Indexed: 11/25/2022]
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13
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Mathiselvam M, Loganathan D, Varghese B. Synthesis of N-(β-D-glycuronopyranosyl)alkanamides and 1-(β-D-glycuronopyranosyl)-4-phenyl-[1,2,3]-triazoles as N-glycoprotein linkage region analogs: examination of the effect of C5 substituent on the N-glycosidic torsion (ΦN) based on X-ray crystallography. Carbohydr Res 2013; 380:1-8. [PMID: 23896157 DOI: 10.1016/j.carres.2013.06.023] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Revised: 06/20/2013] [Accepted: 06/26/2013] [Indexed: 11/30/2022]
Abstract
The torsion angle around the N-glycoprotein linkage region (GlcNAc-Asn) is an important factor for presenting sugar on the cell surface which is crucial for many biological processes. Earlier studies using model and analogs showed that this important torsion angle is greatly influenced by substitutions in the sugar part. In the present work, uronic acid alkanamides and triazole derivatives have been designed and synthesized as newer analogs of N-glycoprotein linkage region to understand the influence of the carboxylic group on linkage region torsion as well as on molecular packing. Crystal structure of N-(β-D-galacturonopyranosyl)acetamide is solved with the space group of P22121. Comparison of the torsion angle and molecular packing of this compound with N-(β-D-galactopyranosyl)acetamide showed that changing the C6-hydoxymethyl group to the carboxylic acid group has minimum influence on the N-glycosidic torsion angle, ΦN and significant influence on the molecular packing.
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Affiliation(s)
- Manoharan Mathiselvam
- Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036, India.
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14
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Farrell M, Zhou J, Murphy PV. Regiospecific Anomerisation of Acylated Glycosyl Azides and Benzoylated Disaccharides by Using TiCl4. Chemistry 2013; 19:14836-51. [DOI: 10.1002/chem.201302572] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2013] [Indexed: 01/28/2023]
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15
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A compendium of cyclic sugar amino acids and their carbocyclic and heterocyclic nitrogen analogues. Amino Acids 2013; 45:613-89. [DOI: 10.1007/s00726-013-1521-1] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Accepted: 05/21/2013] [Indexed: 12/19/2022]
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16
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Bhatt B, Böhm R, Kerry PS, Dyason JC, Russell RJM, Thomson RJ, von Itzstein M. Exploring the interactions of unsaturated glucuronides with influenza virus sialidase. J Med Chem 2012; 55:8963-8. [PMID: 23017008 DOI: 10.1021/jm301145k] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
A series of C3 O-functionalized 2-acetamido-2-deoxy-Δ⁴-β-D-glucuronides were synthesized to explore noncharge interactions in subsite 2 of the influenza virus sialidase active site. In complex with A/N8 sialidase, the parent compound (C3 OH) inverts its solution conformation to bind with all substituents well positioned in the active site. The parent compound inhibits influenza virus sialidase at a sub-μM level; the introduction of small alkyl substituents or an acetyl group at C3 is also tolerated.
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Affiliation(s)
- Beenu Bhatt
- Institute for Glycomics, Gold Coast Campus, Griffith University, Queensland 4222, Australia
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Guerra A, Brea RJ, Amorín M, Castedo L, Granja JR. Self-assembling properties of all γ-cyclic peptides containing sugar amino acid residues. Org Biomol Chem 2012; 10:8762-6. [DOI: 10.1039/c2ob26612a] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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18
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Reddy YS, John Pal AP, Gupta P, Ansari AA, Vankar YD. Ceric Ammonium Nitrate-Catalyzed Azidation of 1,2-Anhydro Sugars: Application in the Synthesis of Structurally Diverse Sugar-Derived Morpholine 1,2,3-Triazoles and 1,4-Oxazin-2-ones. J Org Chem 2011; 76:5972-84. [DOI: 10.1021/jo200260w] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Y. Suman Reddy
- Department of Chemistry, Indian Institute of Technology, Kanpur −208 016, India
| | - A. P. John Pal
- Department of Chemistry, Indian Institute of Technology, Kanpur −208 016, India
| | - Preeti Gupta
- Department of Chemistry, Indian Institute of Technology, Kanpur −208 016, India
| | - Alafia A. Ansari
- Department of Chemistry, Indian Institute of Technology, Kanpur −208 016, India
| | - Yashwant D. Vankar
- Department of Chemistry, Indian Institute of Technology, Kanpur −208 016, India
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Pilgrim W, Murphy PV. SnCl4- and TiCl4-Catalyzed Anomerization of Acylated O- and S-Glycosides: Analysis of Factors That Lead to Higher α:β Anomer Ratios and Reaction Rates. J Org Chem 2010; 75:6747-55. [DOI: 10.1021/jo101090f] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Wayne Pilgrim
- School of Chemistry, National University of Ireland, Galway, Ireland
- Centre for Synthesis and Chemical Biology, School of Chemistry and Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland
| | - Paul V. Murphy
- School of Chemistry, National University of Ireland, Galway, Ireland
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Cipolla L, Redaelli C, Granucci F, Zampella G, Zaza A, Chisci R, Nicotra F. Straightforward synthesis of novel Akt inhibitors based on a glucose scaffold. Carbohydr Res 2010; 345:1291-8. [DOI: 10.1016/j.carres.2009.12.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2009] [Revised: 11/26/2009] [Accepted: 12/13/2009] [Indexed: 02/02/2023]
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21
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Rejzek M, Sri Kannathasan V, Wing C, Preston A, Westman EL, Lam JS, Naismith JH, Maskell DJ, Field RA. Chemical synthesis of UDP-Glc-2,3-diNAcA, a key intermediate in cell surface polysaccharide biosynthesis in the human respiratory pathogens B. pertussis and P. aeruginosa. Org Biomol Chem 2009; 7:1203-10. [PMID: 19262941 DOI: 10.1039/b819607a] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In connection with studies on lipopolysaccharide biosynthesis in respiratory pathogens we had a need to access potential biosynthetic intermediate sugar nucleotides. Herein we report the chemical synthesis of uridine 5'-diphospho 2,3-diacetamido-2,3-dideoxy-alpha-D-glucuronic acid (UDP-Glc-2,3-diNAcA) (1) from N-acetyl-D-glucosamine in 17 steps and approximately 9% overall yield. This compound has proved invaluable in the elucidation of biosynthetic pathways leading to the formation of 2,3-diacetamido-2,3-dideoxy-D-mannuronic acid-containing polysaccharides.
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Affiliation(s)
- Martin Rejzek
- School of Chemical Sciences and Pharmacy, University of East Anglia, Norwich, UK NR4 7TJ
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Synthesis and conformational analysis of methyl 3-amino-2,3-dideoxyhexopyranosiduronic acids, new sugar amino acids, and their diglycotides. Carbohydr Res 2008; 343:1142-52. [DOI: 10.1016/j.carres.2008.02.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2008] [Revised: 02/19/2008] [Accepted: 02/19/2008] [Indexed: 11/19/2022]
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23
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Synthesis and geometry of methyl (methyl 4-O-acetyl-3-azido-2,3-dideoxy-α/β-d-arabino- and -α/β-d-ribo-hexopyranosid)uronates. Carbohydr Res 2008; 343:404-11. [DOI: 10.1016/j.carres.2007.11.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2007] [Revised: 10/26/2007] [Accepted: 11/01/2007] [Indexed: 11/19/2022]
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24
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Gassama A, Hoffmann N. Selective Light Supported Oxidation of Hexoses Using Air as Oxidant – Synthesis of Tetrahydroxyazepanes. Adv Synth Catal 2008. [DOI: 10.1002/adsc.200700282] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Loukou C, Tosin M, Müller-Bunz H, Murphy PV. Synthesis of sugar-lactams from azides of glucuronic acid. Carbohydr Res 2007; 342:1953-9. [PMID: 17477912 DOI: 10.1016/j.carres.2007.04.003] [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] [Received: 02/17/2007] [Revised: 03/31/2007] [Accepted: 04/05/2007] [Indexed: 10/23/2022]
Abstract
Sugar-lactams have found application as glycosidase inhibitors, synthetic precursors of iminosugars and they are structural components of natural products. The synthesis of beta-D-glucopyranosidurono-6,1-lactams from glucuronic acid derivatives are described. NMR data and X-ray crystal structures indicate that the sugar-lactams adopt distorted (1)C4 conformations in solution and in the solid state.
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Affiliation(s)
- Christina Loukou
- UCD School of Chemistry and Chemical Biology, Centre for Synthesis and Chemical Biology, UCD Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
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Risseeuw MD, Overhand M, Fleet GW, Simone MI. A compendium of sugar amino acids (SAA): scaffolds, peptide- and glyco-mimetics. ACTA ACUST UNITED AC 2007. [DOI: 10.1016/j.tetasy.2007.08.004] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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28
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O'Brien C, Poláková M, Pitt N, Tosin M, Murphy PV. Glycosidation-anomerisation reactions of 6,1-anhydroglucopyranuronic acid and anomerisation of beta-D-glucopyranosiduronic acids promoted by SnCl(4). Chemistry 2007; 13:902-9. [PMID: 17086575 DOI: 10.1002/chem.200601111] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The reaction of silylated nucleophiles with 6,1-anhydroglucopyranuronic acid (glucuronic acid 6,1-lactones) catalysed by tin(IV) chloride provides 1,2-trans or 1,2-cis (deoxy)glycosides in a manner dependent on the donor structure. The alpha-glycoside was obtained for reactions of the donor with the 2-acyl group and 2-deoxydonors, whereas the 2-deoxy-2-iodo donor gave the beta-glycoside. Experimental evidence shows that when 1,2-cis-glycoside formation occurs, the anomerisation of initially formed 1,2-trans-glycosides catalysed by SnCl(4) is possible. The anomerisation of beta-D-glucopyranosiduronic acids was found to be faster, in some cases, than anomerisation of related beta-D-glucopyranosiduronic acid esters and beta-D-glucopyranoside derivatives and the rates are dependent on the structure of the aglycon. Moreover, the rates of anomerisation of beta-D-glucopyranuronic acid derivatives can be qualitatively correlated with rates of hydrolysis of beta-D-glucopyranosiduronic acids. Mechanistic possibilities for the reactions are considered.
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Affiliation(s)
- Colin O'Brien
- Centre for Synthesis and Chemical Biology, UCD School of Chemistry and Chemical Biology, Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin 4, Ireland
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Merino P, Franco S, Merchan FL, Tejero T. A Facile Synthesis of Glycosyl Hydroxylamines. SYNTHETIC COMMUN 2006. [DOI: 10.1080/00397919708007074] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- P. Merino
- a Departamento de Química Orgánica, Facultad de Ciencias , ICMA, Universidad de Zaragoza , E-50009, Zaragoza, Aragon, Spain E-mail:
| | - S. Franco
- a Departamento de Química Orgánica, Facultad de Ciencias , ICMA, Universidad de Zaragoza , E-50009, Zaragoza, Aragon, Spain E-mail:
| | - F. L. Merchan
- a Departamento de Química Orgánica, Facultad de Ciencias , ICMA, Universidad de Zaragoza , E-50009, Zaragoza, Aragon, Spain E-mail:
| | - T. Tejero
- a Departamento de Química Orgánica, Facultad de Ciencias , ICMA, Universidad de Zaragoza , E-50009, Zaragoza, Aragon, Spain E-mail:
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Temelkoff DP, Smith CR, Kibler DA, McKee S, Duncan SJ, Zeller M, Hunsen M, Norris P. Application of bis(diphenylphosphino)ethane (DPPE) in Staudinger-type N-glycopyranosyl amide synthesis. Carbohydr Res 2006; 341:1645-56. [PMID: 16499894 DOI: 10.1016/j.carres.2006.02.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2006] [Revised: 01/31/2006] [Accepted: 02/02/2006] [Indexed: 11/24/2022]
Abstract
Bis(diphenylphosphino)ethane (DPPE) reacts with pyranosyl azides derived from D-glucose and D-glucuronic acid in the presence of acid chlorides to yield the corresponding glycosyl amides. Reaction rates are comparable to those with triphenylphosphine, however, the byproduct phosphine oxide is easily removed from reaction mixtures using column chromatography. The simple and clean workup allows for the formation of collections of related compounds by parallel synthesis, and the method is also applicable to scaled-up reactions. The beta-stereochemistry of the glycosyl azide precursor is retained in all cases, which is supported by X-ray crystallography in several cases.
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Affiliation(s)
- David P Temelkoff
- Department of Chemistry, Youngstown State University, 1 University Plaza, Youngstown, OH 44555, USA
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Kumar R, Tiwari P, Maulik PR, Misra AK. A Generalized Procedure for the One-Pot Preparation of Glycosyl Azides and Thioglycosides Directly from Unprotected Reducing Sugars under Phase-Transfer Reaction Conditions. European J Org Chem 2006. [DOI: 10.1002/ejoc.200500646] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Kloth K, Brünjes M, Kunst E, Jöge T, Gallier F, Adibekian A, Kirschning A. Practical TEMPO-Mediated Oxidation of Alcohols using Different Polymer-Bound Co-Oxidants. Adv Synth Catal 2005. [DOI: 10.1002/adsc.200505005] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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34
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Tosin M, O'Brien C, Fitzpatrick GM, Müller-Bunz H, Glass WK, Murphy PV. Synthesis and Structural Analysis of the Anilides of Glucuronic Acid and Orientation of the Groups on the Carbohydrate Scaffolding. J Org Chem 2005; 70:4096-106. [PMID: 15876102 DOI: 10.1021/jo0501994] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
[structures: see text] The synthesis of anilides derived from glucuronic acid is described. Secondary anilides had a Z configuration in the solid state and showed intramolecular and intermolecular hydrogen bonding. However, on the basis of NMR and IR studies, there was generally no evidence for the same hydrogen bonding in solution. Tertiary anilides showed a strong preference for the E configuration on the basis of NOE studies and molecular mechanics calculations. The alkylation of the secondary anilides induces a configurational switch that alters the orientation of the aromatic group with respect to the pyranose, which has relevance for presentation or orientation of pharmacophoric groups on carbohydrate scaffolds.
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Affiliation(s)
- Manuela Tosin
- Centre for Synthesis and Chemical Biology, Department of Chemistry, Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
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35
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Tosin M, Gouin SG, Murphy PV. Synthesis of Structurally Diverse and Defined Bivalent Mannosides on Saccharide Scaffolding. Org Lett 2004; 7:211-4. [PMID: 15646960 DOI: 10.1021/ol047841l] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
[Structure: see text] The synthesis of bivalent mannosides by the grafting of alpha-D-mannopyranoside onto monosaccharide acceptors and conjugation to terephthalic acid or phenylenediamine is described. Computational methods were used to predict accessible orientations and distances between the mannose units.
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Affiliation(s)
- Manuela Tosin
- Centre for Synthesis and Chemical Biology, Chemistry Department, Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
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36
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O'Brien A, Lynch C, O'Boyle KM, Murphy PV. Synthesis of disaccharides derived from heparin and evaluation of effects on endothelial cell growth and on binding of heparin to FGF-2. Carbohydr Res 2004; 339:2343-54. [PMID: 15388349 DOI: 10.1016/j.carres.2004.07.018] [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] [Received: 05/24/2004] [Revised: 07/19/2004] [Accepted: 07/29/2004] [Indexed: 10/26/2022]
Abstract
The disaccharide beta-D-GlcA-(1-->4)-alpha-D-GlcNAc-1-->OMe and other small nonsulfated oligosaccharides related to heparin/heparan sulfate have been shown to bind to FGF and activated the fibroblast growth factor (FGF) signalling pathway in (F32) cells expressing the FGF receptor. Synthetic routes to beta-D-GlcA-(1-->4)-alpha-D-GlcNAc-1-->OMe and a glucose analogue beta-D-Glc-(1-->4)-alpha-D-GlcNAc-1-->OMe are described. The effects of these disaccharides on endothelial cell growth, which is relevant to angiogenesis, were evaluated and it was found they did not mimic the inhibitory effects that were observed for heparin albumin (HA) and that have also been observed by monosaccharide conjugates. They did not alter bovine aortic endothelial cell (BAEC) proliferation, in the presence of FGF-2 in serum free medium or in absence of FGF-2 in serum free and complete medium. Disaccharides (10 microg/mL) reduced by 25-31% the inhibition caused by HA (10 microg/mL) on BAEC growth in serum-free medium but had no effect in complete medium. There was no evidence obtained for the binding of these oligosaccharides to FGF-2 in competition with HA by ELISA.
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Affiliation(s)
- Alan O'Brien
- Centre for Synthesis and Chemical Biology, Department of Chemistry, Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
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37
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Milkereit G, Morr M, Thiem J, Vill V. Thermotropic and lyotropic properties of long chain alkyl glycopyranosides: part III: pH-sensitive headgroups. Chem Phys Lipids 2004; 127:47-63. [PMID: 14706740 DOI: 10.1016/j.chemphyslip.2003.09.007] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
As part of a series of papers, the influence of carbohydrate headgroups and aliphatic chains on the mesogenic properties of glycolipids was investigated. Alkyl glycosides with different types of aliphatic chains were synthesised. Neutral glycolipids were oxidized to their uronic acid derivatives, using the well established TEMPO-oxidation. For comparison a 6-deoxy-6-amino alkylglucopyranoside was synthesised. In addition, the thermotropic and lyotropic phase behaviour of the synthesised compounds were investigated. The thermotropism was characterised by polarising microscopy, the lyotropism by the contact preparation method.
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Affiliation(s)
- G Milkereit
- Institut für Organische Chemie, Universität Hamburg, Martin-Luther-King-Platz 6, 20146, Hamburg, Germany
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38
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Pitt N, Duane RM, O'Brien A, Bradley H, Wilson SJ, O'Boyle KM, Murphy PV. Synthesis of a glucuronic acid and glucose conjugate library and evaluation of effects on endothelial cell growth. Carbohydr Res 2004; 339:1873-87. [PMID: 15261580 DOI: 10.1016/j.carres.2004.05.024] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2004] [Accepted: 05/25/2004] [Indexed: 11/17/2022]
Abstract
Compounds that alter endothelial cell growth are of interest in the development of angiogenesis modulators. A structurally diverse series of saccharide derivatives (glycosylamide conjugates) have been synthesized and evaluated for their effects on bovine aortic endothelial cell (BAEC) growth. Heparin-albumin (HA) reduced BAEC growth by 32% at 10 microg/mL and a number of the novel saccharide conjugates from the library were found to mimic the effect of HA as they also inhibit endothelial cell survival under identical conditions. Two thiophene conjugates, thioglucamide (24% inhibition at 35 microM) and a related glucuronide (26% inhibition at 33 microM) were the most potent inhibitors of BAEC growth, as determined using a methylthiazol tetrazolium (MTT) assay. The effects of thioglucamide and HA on absolute cell number were also studied using cell counting experiments; thioglucamide (47% after 24 h) was more potent than indicated by the MTT assay and initially reduced the BAEC number to a greater extent than HA (30% after 24 h); however, its actions were over more rapidly than were HA's as cell growth had returned to levels of the control after 72 h where HA still caused 25% inhibition. The binding of the monosaccharide conjugates to fibroblast growth factor (FGF-2) in competition with heparin-albumin by ELISA was investigated to establish the possible mechanism by which glycoconjugates could alter growth but there was no general correlation between reduction in viable cell population and binding to FGF-2. No glycoconjugate reduced the proliferation of mouse mammary epithelial cells, nor did any alter gross cell morphology, supporting a proposal that the reduction in BAEC survival by monosaccharide conjugates such as thioglucamide is a result of the inhibition of cell proliferation rather than being an induction of cytotoxicity. These studies indicate that cell biological studies to determine the mechanism of action of the simple monosaccharide conjugates may be worthwhile.
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Affiliation(s)
- Nigel Pitt
- Centre for Synthesis and Chemical Biology, Department of Chemistry, Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
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39
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Reddy BG, Madhusudanan KP, Vankar YD. Trimethylsilylnitrate−Trimethylsilyl Azide: A Novel Reagent System for the Synthesis of 2-Deoxyglycosyl Azides from Glycals. Application in the Synthesis of 2-Deoxy-β-N-glycopeptides. J Org Chem 2004; 69:2630-3. [PMID: 15049677 DOI: 10.1021/jo0354948] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A novel reagent system comprising Me(3)SiN(3) and 20 mol % of Me(3)SiONO(2) permits conversion of glycals to 1-azido 2-deoxy sugars in one step in fair to good yields. Galactals offer higher stereoselectivities than do the glucals. Reduction of the azide group with Ph(3)P-H(2)O to amino functionality followed by coupling with amino acids leads to the synthesis of novel 2-deoxy-beta-N-glycopeptides irrespective of the geometry of initial azido sugars. Using this protocol, a new gamma-sugar amino acid derivative is also procured.
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Affiliation(s)
- B Gopal Reddy
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur-208 016, India
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40
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Abstract
The synthesis of 10 N-(fluoren-9-ylmethoxycarbonyl)glycopyranosylamine uronic acids that are amenable to solid-phase synthesis is described. The general synthetic strategy involves initial incorporation of the protected amine, followed by selective TEMPO oxidation of C-6 hydroxyl groups to give the corresponding Fmoc-protected sugar amino acids. Amine incorporation may be accomplished from aminolysis of the free sugar or from glycosyl azide reduction. The reactions can be carried out on multigram scale, providing access to unique monomer units for future incorporation into combinatorial library syntheses.
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Affiliation(s)
- Laiqiang Ying
- Department of Chemistry, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
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41
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Lichtenthaler FW, Klotz J, Nakamura K. (−)-Daucic acid: Proof of d-lyxo configuration, synthesis of its d-ribo, d-xylo, l-arabino and l-lyxo analogs, and biosynthetic implications. ACTA ACUST UNITED AC 2003. [DOI: 10.1016/j.tetasy.2003.10.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Murphy PV, Bradley H, Tosin M, Pitt N, Fitzpatrick GM, Glass WK. Development of carbohydrate-based scaffolds for restricted presentation of recognition groups. Extension to divalent ligands and implications for the structure of dimerized receptors. J Org Chem 2003; 68:5692-704. [PMID: 12839465 DOI: 10.1021/jo034336d] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The solution structure of glycosyl amides has been studied by using NMR. A strong preference is displayed by tertiary aromatic glycosyl amides for E-anti structures in contrast with secondary aromatic glycosyl amides where Z-anti structures predominate. The structural diversity displayed by these classes of molecules would seem to be important as the directional properties of the aromatic ring, or groups attached to the aromatic ring, would be determined by choosing to have either a secondary or tertiary amide at the anomeric center and could be considered when designing bioactive molecules with carbohydrate scaffolds. The structural analysis was also carried out for related divalent secondary and tertiary glycosyl amides and these compounds display preferences similar to that of the monovalent compounds. The constrained divalent compounds have potential for promoting formation of clusters that will have restricted structure and thus have potential for novel studies of mechanisms of action of multivalent ligands. Possible applications of such compounds would be as scaffolds for the design and synthesis of ligands that will facilitate protein-protein or other receptor-receptor interactions. The affinity of restricted divalent (or higher order) ligands, designed to bind to proteins that recognize carbohydrates which would facilitate clustering and concomitantly promote protein-protein interactions, may be significantly higher than monovalent counterparts or multivalent ligands without these properties. This may be useful as a new approach in the development of therapeutics based on carbohydrates.
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Affiliation(s)
- Paul V Murphy
- Chemistry Department, Centre for Synthesis and Chemical Biology, Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland.
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43
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Abstract
Per-O-acetylated D-glycopyranoses derived from both mono- and disaccharides were first converted to glycosyl iodides and subsequently reacted with an azide source to achieve the stereoselective synthesis of beta-D-glycosyl azides after deacetylation. Low-temperature (4 degrees C) TEMPO oxidation of the monosaccharides provided the corresponding uronic acids, which were purified as the free acids. Oxidation of the lactosyl- and cellobiosyl azides resulted in diacid formation. However, 4',6'-O-benzylidene protection enabled selective oxidation of the C-6 hydroxyl. 2-Acetamido-2-deoxy-D-glycopyranosyl azides were also prepared and converted to uronic acids completing the library synthesis.
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Affiliation(s)
- Laiqiang Ying
- Department of Chemistry, University of California, One Shields Avenue, Davis, CA 95616, USA
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44
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Gruner SAW, Locardi E, Lohof E, Kessler H. Carbohydrate-based mimetics in drug design: sugar amino acids and carbohydrate scaffolds. Chem Rev 2002; 102:491-514. [PMID: 11841252 DOI: 10.1021/cr0004409] [Citation(s) in RCA: 328] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Sibylle A W Gruner
- Institut für Organische Chemie und Biochemie, Technische Universität München, Lichtenbergstrasse 4, D-85747 Garching, Germany
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45
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Bänteli R, Ernst B. Synthesis of sialyl Lewis(x) mimics. Modifications of the 6-position of galactose. Bioorg Med Chem Lett 2001; 11:459-62. [PMID: 11229747 DOI: 10.1016/s0960-894x(00)00692-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Seven sLe(x) mimics where the -CH2OH group of the galactose moiety is replaced by -CH2NH3+, -CH2NHAc, -CH2NHBz, -CH2OSO3Na, -COONa and -CONH2 have been prepared and tested for their binding affinity to E-selectin.
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Affiliation(s)
- R Bänteli
- Novartis Pharma AG, Basel, Switzerland.
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46
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Maruyama M, Takeda T, Shimizu N, Hada N, Yamada H. Synthesis of a model compound related to an anti-ulcer pectic polysaccharide. Carbohydr Res 2000; 325:83-92. [PMID: 10795816 DOI: 10.1016/s0008-6215(99)00315-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
A stereocontrolled synthesis of the model compound for an anti-ulcer active polysaccharide (Bupleuran 2IIc) is described. Glycosidation of the disaccharide acceptor, 2-O-acetyl-3-O-benzyl-4-O-(p-methoxybenzyl)-alpha-L-rhamnopyranosyl-(1-- >4)-2,3,6-tri-O-benzyl-alpha-D-galactopyranosyl trichloroacetimidate, with the disaccharide receptor, allyl 3,4-di-O-benzyl-alpha-L-rhamnopyranosyl-(1-->4)-2,3,6-tri-O-benzyl-beta- D-galactopyranoside, using silver triflate (AgOTf) as a promoter gave the desired tetrasaccharide derivative, which was transformed into the acidic tetrasaccharide, corresponding to a segment of the rhamnogalacturonan (Bupleuran 2IIc) polysaccharide, propyl alpha-L-Rha-(1-->4)-alpha-D-GalA-(1-->2)-alpha-L-Rha-(1-->4)-beta-D-GalA , via removal of the corresponding ether and ester protecting groups, followed by oxidation.
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Affiliation(s)
- M Maruyama
- Koritsu College of Pharmacy, Tokyo, Japan
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47
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Strumpel MK, Buschmann J, Szilágyi L, Györgydeák Z. Synthesis and structural studies of anomeric 2,3,4,6-tetra-O-acetyl-5-thio-d-glucopyranosyl azides. Carbohydr Res 1999. [DOI: 10.1016/s0008-6215(99)00097-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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48
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Lohof E, Burkhart F, Born MA, Planker E, Kessler H. Sugar amino acids and carbohydrates as scaffolds and peptidomimetics. ACTA ACUST UNITED AC 1999. [DOI: 10.1016/s1874-5113(99)80011-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/08/2023]
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49
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Wong AW, He S, Grubb JH, Sly WS, Withers SG. Identification of Glu-540 as the catalytic nucleophile of human beta-glucuronidase using electrospray mass spectrometry. J Biol Chem 1998; 273:34057-62. [PMID: 9852062 DOI: 10.1074/jbc.273.51.34057] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Human beta-glucuronidase is a member of the Family 2 glycosylhydrolases that cleaves beta-D-glucuronic acid residues from the nonreducing termini of glycosaminoglycans. The enzyme is shown to catalyze glycoside bond hydrolysis with net retention of anomeric configuration, presumably via a mechanism involving a covalent glucuronyl-enzyme intermediate. Incubation of human beta-glucuronidase with 2-deoxy-2-fluoro-beta-D-glucuronyl fluoride resulted in time-dependent inactivation of the enzyme through the accumulation of a covalent 2-deoxy-2-fluoro-alpha-D-glucuronyl-enzyme, as observed by electrospray mass spectrometry. Regeneration of the free enzyme by hydrolysis or transglycosylation and removal of excess inactivator demonstrated that the covalent intermediate was kinetically competent. Peptic digestion of the 2-deoxy-2-fluoro-alpha-D-glucuronyl-enzyme intermediate and subsequent analysis by liquid chromatography coupled with electrospray ionization triple quadrupole mass spectrometry indicated the presence of a 2-deoxy-2-fluoro-alpha-D-glucuronyl peptide. Sequence determination of the labeled peptide by tandem mass spectrometry in the daughter ion scan mode permitted the identification of Glu-540 as the catalytic nucleophile within the sequence SEYGAET.
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Affiliation(s)
- A W Wong
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
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50
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Mlynarski J, Banaszek A. Convenient preparation of α- and β-glycosides of novel isomeric 3-deoxy-hept-2-ulosaric acids diesters. Tetrahedron 1997. [DOI: 10.1016/s0040-4020(97)00675-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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