1
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Goi S, Shigeta H, Takahashi D, Toshima K. Photo-induced glycosylation using the edible polyphenol curcumin. Org Biomol Chem 2024; 22:5546-5551. [PMID: 38814007 DOI: 10.1039/d4ob00624k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2024]
Abstract
Photo-induced glycosylations of trichloroacetimidate donors and alcohols using an edible polyphenol, curcumin, were examined under visible photo-irradiation (470 nm). It was found, for the first time, that these glycosylations proceed smoothly under mild reaction conditions to give the corresponding glycosides in high yields. In addition, the present glycosylation method was applicable to a wide range of trichloroacetimidate donors and alcohol acceptors and showed high chemoselectivity over glycosyl phosphite, phosphate, (N-phenyl)trifluoroacetimidate, fluoride, glycal and thioglycoside.
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Affiliation(s)
- Satomi Goi
- Department of Applied Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan.
| | - Hidenari Shigeta
- Department of Applied Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan.
| | - Daisuke Takahashi
- Department of Applied Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan.
| | - Kazunobu Toshima
- Department of Applied Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan.
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2
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Geulin A, Bourne-Branchu Y, Ben Ayed K, Lecourt T, Joosten A. Ferrier/Aza-Wacker/Epoxidation/Glycosylation (FAWEG) Sequence to Access 1,2-Trans 3-Amino-3-deoxyglycosides. Chemistry 2023; 29:e202203987. [PMID: 36793144 DOI: 10.1002/chem.202203987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Indexed: 02/17/2023]
Abstract
3-Amino-3-deoxyglycosides constitute an essential class of nitrogen-containing sugars. Among them, many important 3-amino-3-deoxyglycosides possess a 1,2-trans relationship. In view of their numerous biological applications, the synthesis of 3-amino-3-deoxyglycosyl donors giving rise to a 1,2-trans glycosidic linkage is thus an important challenge. Even though glycals are highly polyvalent donors, the synthesis and reactivity of 3-amino-3-deoxyglycals have been little studied. In this work, we describe a new sequence, involving a Ferrier rearrangement and subsequent aza-Wacker cyclization that allows the rapid synthesis of orthogonally protected 3-amino-3-deoxyglycals. Finally a 3-amino-3-deoxygalactal derivative was submitted for the first time to an epoxidation/glycosylation with high yield and great diastereoselectivity, highlighting FAWEG (Ferrier/Aza-Wacker/Epoxidation/Glycosylation) as a new approach to access 1,2-trans 3-amino-3-deoxyglycosides.
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Affiliation(s)
- Anselme Geulin
- Normandie Univ, INSA Rouen, UNIROUEN, CNRS, COBRA UMR 6014, 76000, Rouen, France
- 24 Rue Lucien Tesnière, 76130, Mont-Saint-Aignan, France
| | - Yann Bourne-Branchu
- Normandie Univ, INSA Rouen, UNIROUEN, CNRS, COBRA UMR 6014, 76000, Rouen, France
- 24 Rue Lucien Tesnière, 76130, Mont-Saint-Aignan, France
| | - Kawther Ben Ayed
- Normandie Univ, INSA Rouen, UNIROUEN, CNRS, COBRA UMR 6014, 76000, Rouen, France
- 24 Rue Lucien Tesnière, 76130, Mont-Saint-Aignan, France
| | - Thomas Lecourt
- Normandie Univ, INSA Rouen, UNIROUEN, CNRS, COBRA UMR 6014, 76000, Rouen, France
- 24 Rue Lucien Tesnière, 76130, Mont-Saint-Aignan, France
| | - Antoine Joosten
- Normandie Univ, INSA Rouen, UNIROUEN, CNRS, COBRA UMR 6014, 76000, Rouen, France
- 24 Rue Lucien Tesnière, 76130, Mont-Saint-Aignan, France
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3
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Traboni S, Bedini E, Silipo A, Vessella G, Iadonisi A. Solvent‐Free Glycosylation from per‐
O
‐Acylated Donors Catalyzed by Methanesulfonic Acid. European J Org Chem 2021. [DOI: 10.1002/ejoc.202101121] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Serena Traboni
- Department of Chemical Sciences University of Naples Federico II Via Cinthia 4 80126 Naples Italy
| | - Emiliano Bedini
- Department of Chemical Sciences University of Naples Federico II Via Cinthia 4 80126 Naples Italy
| | - Alba Silipo
- Department of Chemical Sciences University of Naples Federico II Via Cinthia 4 80126 Naples Italy
| | - Giulia Vessella
- Department of Chemical Sciences University of Naples Federico II Via Cinthia 4 80126 Naples Italy
| | - Alfonso Iadonisi
- Department of Chemical Sciences University of Naples Federico II Via Cinthia 4 80126 Naples Italy
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4
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Traboni S, Vessella G, Bedini E, Iadonisi A. Solvent-free, under air selective synthesis of α-glycosides adopting glycosyl chlorides as donors. Org Biomol Chem 2021; 18:5157-5163. [PMID: 32583825 DOI: 10.1039/d0ob01024c] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
α-Glycosides are highly relevant synthetic targets due to their abundance in natural oligosaccharides involved in many biological processes. Nevertheless their preparation is hampered by several issues, due to both the strictly anhydrous conditions typically required in glycosylation procedures and the non-trivial achievement of high α-stereoselectivity, one of the major challenges in oligosaccharide synthesis. In this paper we report a novel and efficient approach for the highly stereoselective synthesis of α-glycosides. This is based on the unprecedented solvent-free combination of triethylphosphite, tetrabutylammonium bromide and N,N-diisopropylethylamine for the activation of glycosyl chlorides under air. Despite the relative stability of glycosyl chlorides with respect to more reactive halide donors, the solvent-free procedure allowed a wide set of α-glycosides, including biorelevant fragments, to be obtained in much shorter times compared with similar glycosylation approaches in solution. The presented method features a wide target scope and functional group compatibility, also serving with partially disarmed substrates, and it does not require a high stoichiometric excess of reagents nor the preparation of expensive precursors. The solvent-free glycosylation can be even directly performed from 1-hydroxy sugars without purification of the in situ generated chloride, providing an especially useful opportunity in the case of highly reactive and labile glycosyl donors.
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Affiliation(s)
- Serena Traboni
- Department of Chemical Sciences, University of Naples Federico II, Via Cinthia 4, I-80126 Naples, Italy.
| | - Giulia Vessella
- Department of Chemical Sciences, University of Naples Federico II, Via Cinthia 4, I-80126 Naples, Italy.
| | - Emiliano Bedini
- Department of Chemical Sciences, University of Naples Federico II, Via Cinthia 4, I-80126 Naples, Italy.
| | - Alfonso Iadonisi
- Department of Chemical Sciences, University of Naples Federico II, Via Cinthia 4, I-80126 Naples, Italy.
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5
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Sollert C, Kocsi D, Jane RT, Orthaber A, Borbas KE. C-glycosylated pyrroles and their application in dipyrromethane and porphyrin synthesis. J PORPHYR PHTHALOCYA 2021. [DOI: 10.1142/s1088424621500723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Pyrrole C-glycosylated in either the 2- or the 3-position could be prepared by the acid-catalyzed reaction between trichloroacetimidate glycosyl donors and pyrrole, or [Formula: see text]-phenyl-tri?uoroacetimidate glucosyl donor and [Formula: see text]-TIPS pyrrole, respectively. Pyrroles carrying glucose, mannose, galactose and lactose in the 2-position, and glucose in the 3-position were obtained. The configurations of the products could be assigned using a combination of 1D and 2D NMR spectroscopy. A number of undesired background reactions yielding a variety of stereo- and regioisomers were identified; in several cases these could be eliminated. Glycosylpyrroles could be incorporated into mono- and diglycosylated dipyrromethanes, a diglycosylated BODIPY dye, and a monoglycosylated Zn(II) porphyrin without damaging the sugar unit.
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Affiliation(s)
- Carina Sollert
- Department of Chemistry, Ångström Laboratory, Box 523, Uppsala University, 75120 Uppsala, Sweden
| | - Daniel Kocsi
- Department of Chemistry, Ångström Laboratory, Box 523, Uppsala University, 75120 Uppsala, Sweden
| | - Reuben T. Jane
- Department of Chemistry, Ångström Laboratory, Box 523, Uppsala University, 75120 Uppsala, Sweden
| | - Andreas Orthaber
- Department of Chemistry, Ångström Laboratory, Box 523, Uppsala University, 75120 Uppsala, Sweden
| | - K. Eszter Borbas
- Department of Chemistry, Ångström Laboratory, Box 523, Uppsala University, 75120 Uppsala, Sweden
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6
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Vessella G, Traboni S, Laezza A, Iadonisi A, Bedini E. (Semi)-Synthetic Fucosylated Chondroitin Sulfate Oligo- and Polysaccharides. Mar Drugs 2020; 18:E293. [PMID: 32492857 PMCID: PMC7345195 DOI: 10.3390/md18060293] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 05/27/2020] [Accepted: 05/28/2020] [Indexed: 12/14/2022] Open
Abstract
Fucosylated chondroitin sulfate (fCS) is a glycosaminoglycan (GAG) polysaccharide with a unique structure, displaying a backbone composed of alternating N-acetyl-d-galactosamine (GalNAc) and d-glucuronic acid (GlcA) units on which l-fucose (Fuc) branches are installed. fCS shows several potential biomedical applications, with the anticoagulant activity standing as the most promising and widely investigated one. Natural fCS polysaccharides extracted from marine organisms (Echinoidea, Holothuroidea) present some advantages over a largely employed antithrombotic drug such as heparin, but some adverse effects as well as a frequently found structural heterogeneity hamper its development as a new drug. To circumvent these drawbacks, several efforts have been made in the last decade to obtain synthetic and semi-synthetic fCS oligosaccharides and low molecular weight polysaccharides. In this Review we have for the first time collected these reports together, dividing them in two topics: (i) total syntheses of fCS oligosaccharides and (ii) semi-synthetic approaches to fCS oligosaccharides and low molecular weight polysaccharides as well as glycoclusters displaying multiple copies of fCS species.
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Affiliation(s)
- Giulia Vessella
- Department of Chemical Sciences, University of Naples Federico II, Complesso Universitario Monte S. Angelo, via Cintia 4, I-80126 Napoli, Italy; (G.V.); (S.T.); (A.I.)
| | - Serena Traboni
- Department of Chemical Sciences, University of Naples Federico II, Complesso Universitario Monte S. Angelo, via Cintia 4, I-80126 Napoli, Italy; (G.V.); (S.T.); (A.I.)
| | - Antonio Laezza
- Department of Sciences, University of Basilicata, viale dell’Ateneo Lucano 10, I-85100 Potenza, Italy;
| | - Alfonso Iadonisi
- Department of Chemical Sciences, University of Naples Federico II, Complesso Universitario Monte S. Angelo, via Cintia 4, I-80126 Napoli, Italy; (G.V.); (S.T.); (A.I.)
| | - Emiliano Bedini
- Department of Chemical Sciences, University of Naples Federico II, Complesso Universitario Monte S. Angelo, via Cintia 4, I-80126 Napoli, Italy; (G.V.); (S.T.); (A.I.)
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7
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Kowalska K, Pedersen CM. α-Selective glycosylations using glycosyl N-(ortho-methoxyphenyl)trifluoroacetimidates. Org Biomol Chem 2020; 18:1918-1925. [PMID: 32101221 DOI: 10.1039/c9ob02696g] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Six N-(o-methoxyphenyl)trifluoroacetimidate glycosyl donors have been synthesized and their role as glycosyl donors has been investigated. The donors were synthesized with complete β-selectivity, except in one case, and were found to be stable. When Bi(OTf)3, Fe(OTf)2, and Zn(OTf)2 were employed as catalysts, the glycosylations were found to be highly α-selective in Et2O. The selectivity and reaction rate changed with a change in the acceptor reactivity.
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Affiliation(s)
- Karolina Kowalska
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark. and Faculty of Chemistry, Adam Mickiewicz University in Poznań, ul. Uniwersytetu Poznańskiego 8, 61-614 Poznań, Poland
| | - Christian Marcus Pedersen
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark.
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8
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A Study for the Access to a Semi-synthetic Regioisomer of Natural Fucosylated Chondroitin Sulfate with Fucosyl Branches on N-acetyl-Galactosamine Units. Mar Drugs 2019; 17:md17120655. [PMID: 31766509 PMCID: PMC6950142 DOI: 10.3390/md17120655] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 11/14/2019] [Accepted: 11/16/2019] [Indexed: 12/20/2022] Open
Abstract
Fucosylated chondroitin sulfate (fCS) is a glycosaminoglycan found up to now exclusively in the body wall of sea cucumbers. It shows several interesting activities, with the anticoagulant and antithrombotic as the most attractive ones. Its different mechanism of action on the blood coagulation cascade with respect to heparin and the retention of its activity by oral administration make fCS a very promising anticoagulant drug candidate for heparin replacement. Nonetheless, its typically heterogeneous structure, the detection of some adverse effects and the preference for new drugs not sourced from animal tissues, explain how mandatory is to open an access to safer and less heterogeneous non-natural fCS species. Here we contribute to this aim by investigating a suitable chemical strategy to obtain a regioisomer of the natural fCS polysaccharide, with sulfated l-fucosyl branches placed at position O-6 of N-acetyl-d-galactosamine (GalNAc) units instead of O-3 of d-glucuronic acid (GlcA) ones, as in natural fCSs. This strategy is based on the structural modification of a microbial sourced chondroitin polysaccharide by regioselective insertion of fucosyl branches and sulfate groups on its polymeric structure. A preliminary in vitro evaluation of the anticoagulant activity of three of such semi-synthetic fCS analogues is also reported.
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9
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Affiliation(s)
- Michael Martin Nielsen
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
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10
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Smith DG, Williams SJ. A carbon tetrachloride-free synthesis of N -phenyltrifluoroacetimidoyl chloride. Carbohydr Res 2017; 450:10-11. [DOI: 10.1016/j.carres.2017.08.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 08/09/2017] [Accepted: 08/09/2017] [Indexed: 11/16/2022]
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11
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Laezza A, Iadonisi A, Pirozzi AVA, Diana P, De Rosa M, Schiraldi C, Parrilli M, Bedini E. A Modular Approach to a Library of Semi-Synthetic Fucosylated Chondroitin Sulfate Polysaccharides with Different Sulfation and Fucosylation Patterns. Chemistry 2016; 22:18215-18226. [DOI: 10.1002/chem.201603525] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Indexed: 11/07/2022]
Affiliation(s)
- Antonio Laezza
- Department of Chemical Sciences; University of Naples Federico II, Complesso Universitario Monte S. Angelo; via Cintia 4 80126 Naples Italy
| | - Alfonso Iadonisi
- Department of Chemical Sciences; University of Naples Federico II, Complesso Universitario Monte S. Angelo; via Cintia 4 80126 Naples Italy
| | - Anna V. A. Pirozzi
- Department of Experimental Medicine; Second University of Naples; via de Crecchio 7 80138 Naples Italy
| | - Paola Diana
- Department of Experimental Medicine; Second University of Naples; via de Crecchio 7 80138 Naples Italy
| | - Mario De Rosa
- Department of Experimental Medicine; Second University of Naples; via de Crecchio 7 80138 Naples Italy
| | - Chiara Schiraldi
- Department of Experimental Medicine; Second University of Naples; via de Crecchio 7 80138 Naples Italy
| | - Michelangelo Parrilli
- Department of Biology; University of Naples Federico II, Complesso Universitario Monte S. Angelo; via Cintia 4 80126 Naples Italy
| | - Emiliano Bedini
- Department of Chemical Sciences; University of Naples Federico II, Complesso Universitario Monte S. Angelo; via Cintia 4 80126 Naples Italy
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12
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Laezza A, Iadonisi A, Castro CD, De Rosa M, Schiraldi C, Parrilli M, Bedini E. Chemical Fucosylation of a Polysaccharide: A Semisynthetic Access to Fucosylated Chondroitin Sulfate. Biomacromolecules 2015; 16:2237-45. [DOI: 10.1021/acs.biomac.5b00640] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Antonio Laezza
- Department
of Chemical Sciences, University of Naples Federico II, Complesso Universitario Monte S.Angelo, via Cintia 4, I-80126 Napoli, Italy
| | - Alfonso Iadonisi
- Department
of Chemical Sciences, University of Naples Federico II, Complesso Universitario Monte S.Angelo, via Cintia 4, I-80126 Napoli, Italy
| | - Cristina De Castro
- Department
of Soil, Plant, Environmental, and Animal Production Sciences, University of Naples Federico II, via Università 100, I-80055 Portici, Italy
| | - Mario De Rosa
- Department
of Experimental Medicine, Second University of Naples, via de Crecchio
7, I-80138 Napoli, Italy
| | - Chiara Schiraldi
- Department
of Experimental Medicine, Second University of Naples, via de Crecchio
7, I-80138 Napoli, Italy
| | - Michelangelo Parrilli
- Department
of Biology, University of Naples Federico II, Complesso Universitario Monte S.Angelo, via Cintia 4, I-80126 Napoli, Italy
| | - Emiliano Bedini
- Department
of Chemical Sciences, University of Naples Federico II, Complesso Universitario Monte S.Angelo, via Cintia 4, I-80126 Napoli, Italy
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13
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Guiard J, Paszkiewicz E, Sadowska J, Bundle DR. Design and Synthesis of a Universal Antigen to Detect Brucellosis. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201302303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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14
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Guiard J, Paszkiewicz E, Sadowska J, Bundle DR. Design and Synthesis of a Universal Antigen to Detect Brucellosis. Angew Chem Int Ed Engl 2013; 52:7181-5. [DOI: 10.1002/anie.201302303] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Indexed: 11/06/2022]
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15
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Calin O, Eller S, Hahm HS, Seeberger PH. Total synthesis of the Escherichia coli O111 O-specific polysaccharide repeating unit. Chemistry 2013; 19:3995-4002. [PMID: 23447496 DOI: 10.1002/chem.201204394] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Indexed: 01/28/2023]
Abstract
The first total synthesis of the O-antigen pentasaccharide repeating unit from Gram-negative bacteria Escherichia coli O111 was achieved starting from four monosaccharide building blocks. Key to the synthetic approach was a bis-glycosylation reaction to combine trisaccharide 10 and colitose 5. The colitose building block (5) was obtained de novo from non-carbohydrate precursors. The pentasaccharide was equipped at the reducing end with an amino spacer to provide a handle for subsequent conjugation to a carrier protein in anticipation of immunological studies.
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Affiliation(s)
- Oliviana Calin
- Department of Biomolecular Systems, Max Planck Institute of Colloids and Interfaces, Am Mühlenberg 1, 14476 Potsdam, Germany
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16
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17
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Bedini E, Cirillo L, Parrilli M. Synthesis of the trisaccharide outer core fragment of Burkholderia cepacia pv. vietnamiensis lipooligosaccharide. Carbohydr Res 2012; 349:24-32. [DOI: 10.1016/j.carres.2011.12.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2011] [Revised: 11/29/2011] [Accepted: 12/06/2011] [Indexed: 10/14/2022]
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18
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Blaukopf M, Müller B, Hofinger A, Kosma P. Synthesis of Neoglycoconjugates Containing 4-Amino-4-deoxy-l-arabinose Epitopes Corresponding to the Inner Core of Burkholderia and Proteus Lipopolysaccharides. European J Org Chem 2011; 2012:119-131. [PMID: 23136534 PMCID: PMC3482937 DOI: 10.1002/ejoc.201101171] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2011] [Indexed: 11/08/2022]
Abstract
Disaccharides that contain 3-deoxy-d-manno-oct-2-ulosonic acid (Kdo) and d-glycero-d-talo-oct-2-ulosonic acid (Ko) substituted at the 8-position by 4-amino-4-deoxy-β-l-arabinopyranosyl (Ara4N) residues have been prepared. Coupling an N-phenyltrifluoroacetimidate-4-azido-4-deoxy-l-arabinosylglycosyl donor to acetyl-protected allyl glycosides of Kdo and Ko afforded anomeric mixtures of disaccharide products in 74 and 90 % yield, respectively, which were separated by chromatography. Further extension of an intermediate Ara4N-(1→8)-Kdo disaccharide acceptor, which capitalized on a regioselective glycosylation with a Kdo bromide donor under Helferich conditions, afforded the branched trisaccharide α-Kdo-(2→4)[β-l-Ara4N-(1→8)]-α-Kdo derivative. Deprotection of the protected di- and trisaccharide allyl glycosides was accomplished by TiCl4-promoted benzyl ether cleavage followed by the removal of ester groups and reduction of the azido group with thiol or Staudinger reagents, respectively. The reaction of the anomeric allyl group with 1,3-propanedithiol under radical conditions afforded the thioether-bridged spacer glycosides, which were efficiently coupled to maleimide-activated bovine serum albumin. The neoglycoconjugates serve as immunoreagents with specificity for inner core epitopes of Burkholderia and Proteus lipopolysaccharides.
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Affiliation(s)
- Markus Blaukopf
- Department of Chemistry, University of Natural Resources and Life Sciences Muthgasse 18, 1190 Vienna, Austria
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19
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Pragani R, Seeberger PH. Total synthesis of the Bacteroides fragilis zwitterionic polysaccharide A1 repeating unit. J Am Chem Soc 2010; 133:102-7. [PMID: 21142035 DOI: 10.1021/ja1087375] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Nearly all bacteria capsular polysaccharides are T-cell-independent antigens that do not promote immunoglobulin class switching from IgM to IgG nor memory responses. In contrast, zwitterionic polysaccharides activate T-cell-dependent immune responses by major histocompatability complex class II presentation, a mechanism previously believed to be reserved for peptidic antigens. The best studied zwitterionic polysaccharide, polysaccharide A1 (PS A1) is found on the capsule of the commensal bacteria Bacteroides fragilis . Its potent immunomodulatory properties have been linked to postoperative intra-abdominal abscess formation. Here, we report the synthesis of the PS A1 tetrasaccharide repeating unit (2) as a tool to investigate the biological role of this polysaccharide. A modular synthetic strategy originating from the reducing end of the PS A1 repeating unit was unsuccessful and illustrated the limitations of glycosylation reactions between highly armed glycosylating agents and poor nucleophiles. Thus, a [3 + 1] glycosylation relying on trisaccharide 5 and pyruvalated galactose 6 was used to complete the first total synthesis of the PS A1 repeating unit (2).
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Affiliation(s)
- Rajan Pragani
- Max Planck Institute of Colloids and Interfaces, Department of Biomolecular Systems, Am Mühlenberg 1, 14476 Potsdam, Germany
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20
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Pragani R, Stallforth P, Seeberger PH. De novo synthesis of a 2-acetamido-4-amino-2,4,6-trideoxy-D-galactose (AAT) building block for the preparation of a Bacteroides fragilis A1 polysaccharide fragment. Org Lett 2010; 12:1624-7. [PMID: 20196573 DOI: 10.1021/ol1003912] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Zwitterionic polysaccharides (ZPSs) are potent T-cell activators that naturally occur on the cell surface of bacteria and show potential as immunostimulatory agents. An unusual, yet important component of many ZPSs is 2-acetamido-4-amino-2,4,6-trideoxy-D-galactose (AAT). AAT building block 2 was prepared via a de novo synthesis from N-Cbz-L-threonine 5. Furthermore, building block 2 was used to synthesize disaccharide 15 that constitutes a fragment of zwitterionic polysaccharide A1 (PS A1) found in Bacteroides fragilis.
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Affiliation(s)
- Rajan Pragani
- Max-Planck-Institute of Colloids and Interfaces, Department of Biomolecular Systems, Am Muhlenberg 1, 14476 Potsdam, Germany
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21
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Cirillo L, Silipo A, Bedini E, Parrilli M. A Urea-Linked Glucosamine Dimer as a Building Block for the Synthesis of Linear and Cyclic Neosaccharides. European J Org Chem 2010. [DOI: 10.1002/ejoc.201000292] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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