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Wu P, Xiao X, Zhou S, Meng L, Zeng J, Wan Q. Glycosylation of 2-(2-Propylsulfinyl)benzyl 1,2-Orthoester Glycosides Initiated by Sulfoxide Activation. Org Lett 2024; 26:6053-6058. [PMID: 38985301 DOI: 10.1021/acs.orglett.4c02210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/11/2024]
Abstract
We have developed a highly effective glycosylation method that involves the activation of 2-(2-propylsulfinyl)benzyl 1,2-orthoester glycosides using triflic anhydride (Tf2O). Our research indicates that half of the glycosyl donor is activated through Tf2O via an interrupted Pummerer reaction mechanism, while the remaining portion is activated by triflic acid (TfOH) generated in situ. As a result, as little as 0.5 equiv of Tf2O is adequate for activating the orthoester glycoside donors. This glycosylation procedure offers several benefits, such as high efficiency, wide applicability, and the utilization of a recyclable leaving group.
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Affiliation(s)
- Pinru Wu
- School of Pharmacy, Huazhong University of Science and Technology, Wuhan, Hubei 430030, P. R. of China
| | - Xiong Xiao
- School of Chemistry and Chemical Engineering, Northwestern Polytechnical University, Xi'an, Shannxi 700072, P. R. of China
| | - Sicheng Zhou
- School of Pharmacy, Huazhong University of Science and Technology, Wuhan, Hubei 430030, P. R. of China
| | - Lingkui Meng
- School of Pharmacy, Huazhong University of Science and Technology, Wuhan, Hubei 430030, P. R. of China
| | - Jing Zeng
- School of Pharmacy, Huazhong University of Science and Technology, Wuhan, Hubei 430030, P. R. of China
| | - Qian Wan
- School of Pharmacy, Huazhong University of Science and Technology, Wuhan, Hubei 430030, P. R. of China
- School of Pharmaceutical Sciences, Wuhan University, Wuhan, Hubei 430071, P. R. of China
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2
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Wang L, Guo Z. An extensive review of studies on mycobacterium cell wall polysaccharide-related oligosaccharides – part I: Synthetic studies on arabinofuranosyl oligosaccharides. J Carbohydr Chem 2019. [DOI: 10.1080/07328303.2019.1630839] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Lizhen Wang
- Biology Institute, Qilu University of Technology (Shandong Academy of Sciences), Ji'nan, China
| | - Zhongwu Guo
- Department of Chemistry, University of Florida, Gainesville, FL, USA
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3
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[Au]/[Ag]-catalysed expedient synthesis of branched heneicosafuranosyl arabinogalactan motif of Mycobacterium tuberculosis cell wall. Nat Commun 2017; 8:14019. [PMID: 28120821 PMCID: PMC5288502 DOI: 10.1038/ncomms14019] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Accepted: 11/22/2016] [Indexed: 01/18/2023] Open
Abstract
Emergence of multidrug-resistant and extreme-drug-resistant strains of Mycobacterium tuberculosis (MTb) can cause serious socioeconomic burdens. Arabinogalactan present on the cellular envelope of MTb is unique and is required for its survival; access to arabinogalactan is essential for understanding the biosynthetic machinery that assembles it. Isolation from Nature is a herculean task and, as a result, chemical synthesis is the most sought after technique. Here we report a convergent synthesis of branched heneicosafuranosyl arabinogalactan (HAG) of MTb. Key furanosylations are performed using [Au]/[Ag] catalysts. The synthesis of HAG is achieved by the repetitive use of three reactions namely 1,2-trans furanoside synthesis by propargyl 1,2-orthoester donors, unmasking of silyl ether, and conversion of n-pentenyl furanosides into 1,2-orthoesters. Synthesis of HAG is achieved in 47 steps (with an overall yield of 0.09%) of which 21 are installation of furanosidic linkages in a stereoselective manner. Arabinogalactan forms parts of the cellular envelope of Mycobacterium tuberculosis, however due to its size chemical synthesis is a massive task. Here the authors report the synthesis of branched heneicosafuranosyl arabinogalactan fragment by repeated use of a Au/Ag-catalysed glycosylation methodology.
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Lee BY, Oh JW, Baek JY, Jeon HB, Kim KS. Phthalic Anhydride-Mediated Direct Glycosylation of Anomeric Hydroxy Arabinofuranose: Synthesis of Repeating Oligoarabinofuranoside and Tetradecasaccharide Arabinan Motif of Mycobacterial Cell Wall. J Org Chem 2016; 81:11372-11383. [DOI: 10.1021/acs.joc.6b01723] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Bo-Young Lee
- Center
for Bioactive Molecular Hybrids and Department of Chemistry, Yonsei University, Seoul 120-749, Korea
| | - Jung Woo Oh
- Center
for Bioactive Molecular Hybrids and Department of Chemistry, Yonsei University, Seoul 120-749, Korea
| | - Ju Yuel Baek
- Center
for Bioactive Molecular Hybrids and Department of Chemistry, Yonsei University, Seoul 120-749, Korea
| | - Heung Bae Jeon
- Department
of Chemistry, Kwangwoon University, Seoul 139-701, Korea
| | - Kwan Soo Kim
- Center
for Bioactive Molecular Hybrids and Department of Chemistry, Yonsei University, Seoul 120-749, Korea
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5
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Wang L, Feng S, An L, Gu G, Guo Z. Synthetic and Immunological Studies of Mycobacterial Lipoarabinomannan Oligosaccharides and Their Protein Conjugates. J Org Chem 2015; 80:10060-75. [DOI: 10.1021/acs.joc.5b01686] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Lizhen Wang
- National Glycoengineering
Research Center, School of Life Science, Shandong University, Jinan 250100, China
| | - Shaojie Feng
- National Glycoengineering
Research Center, School of Life Science, Shandong University, Jinan 250100, China
| | - Lian An
- National Glycoengineering
Research Center, School of Life Science, Shandong University, Jinan 250100, China
| | - Guofeng Gu
- National Glycoengineering
Research Center, School of Life Science, Shandong University, Jinan 250100, China
| | - Zhongwu Guo
- National Glycoengineering
Research Center, School of Life Science, Shandong University, Jinan 250100, China
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Islam M, Gayatri G, Hotha S. Influence of Steric Crowding on Diastereoselective Arabinofuranosylations. J Org Chem 2015. [PMID: 26195010 DOI: 10.1021/acs.joc.5b00964] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The occurrence of arabinofuranosides on the cell surface of Mycobacterium tuberculosis (Mtb) and their significance in controlling disease spurred interest in developing strategies for their diastereoselective synthesis. Mtb uses enzymes to achieve diastereoselectivity through noncovalent interactions. Of the two possible glycosidic linkages, chemically, 1,2-trans linkage is relatively easy to synthesize by taking advantage of neighboring group participation, whereas synthesis of the 1,2-cis linkage is notoriously difficult. In this article, stereochemical effects on the diastereoselectivity of arabinofuranosidation are investigated with thiopyridyl, imidate, and thiotolyl donors as well as differently crowded glycosyl acceptors; subtle differences in the stereochemical environment of the acceptors were observed to alter the diastereoselectivity of the furanoside formation. Results from this endeavor suggest that 1,2-cis arabinofuranosides can be synthesized conveniently by conducting the reaction at lower temperature on sterically demanding and less reactive substrates.
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Affiliation(s)
- Maidul Islam
- †Department of Chemistry, Indian Institute of Science Education and Research, Pune 411 008, India
| | - Gaddamanugu Gayatri
- ‡Centre for Molecular Modelling, Indian Institute of Chemical Technology, Hyderabad 500 007, India
| | - Srinivas Hotha
- †Department of Chemistry, Indian Institute of Science Education and Research, Pune 411 008, India
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Thadke SA, Mishra B, Hotha S. Gold(III)-catalyzed glycosidations for 1,2-trans and 1,2-cis furanosides. J Org Chem 2014; 79:7358-71. [PMID: 25020110 DOI: 10.1021/jo501052y] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Stereoselective synthesis of furanosides is still a daunting task, unlike the pyranosides, for which several methods exist. Herein, a unified stereoselective strategy for the synthesis of 1,2-trans and 1,2-cis furanosides is revealed for seven out of eight possible isomers of pentoses. The identified protocol gives access to diastereoselective synthesis of α- and β-araf, ribf, lyxf, and α-xylf furanosides. 1,2-trans glycosides were synthesized by the use of propargyl 1,2-orthoesters under gold-catalyzed glycosidation conditions, and subsequently, they are converted into 1,2-cis glycosides through oxidation-reduction as the key functional group transformation. All the reactions are found to be fully diastereoselective, mild, and high yielding.
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Affiliation(s)
- Shivaji A Thadke
- Department of Chemistry, Indian Institute of Science Education and Research , Pune, Maharashtra 411008, India
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8
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Ranade SC, Demchenko AV. Mechanism of Chemical Glycosylation: Focus on the Mode of Activation and Departure of Anomeric Leaving Groups. J Carbohydr Chem 2013. [DOI: 10.1080/07328303.2012.749264] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Sneha C. Ranade
- a Department of Chemistry and Biochemistry , University of Missouri , St. Louis , MO , 63121 , USA
| | - Alexei V. Demchenko
- a Department of Chemistry and Biochemistry , University of Missouri , St. Louis , MO , 63121 , USA
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Fraser-Reid B, Lopez JC, Bernal-Albert P, Gomez AM, Uriel C, Ventura J. Glycosyl fluorides from n-pentenyl-related glycosyl donors — Application to glycosylation strategies. CAN J CHEM 2013. [DOI: 10.1139/cjc-2012-0285] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
n-Pentenyl glycosides (NPGs) and n-pentenyl orthoesters (NPOEs) have been transformed into glycosyl fluorides by a variety of methods. In the case of NPGs, Barluenga’s reagent, bis(pyridinium)iodonium(I)tetrafluoroborate (IPy2BF4), gives good yields of glycosyl fluorides when HF–pyridine complex is used as an additional fluoride source. NPOEs can be activated either by a combination of electrophilic iodonium (Barluenga’s reagent) and HBF4 or by the action of HF–pyridine complex. The ensuing glycosyl fluorides form a semiorthogonal pair of glycosyl donors when confronted with NPGs.
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Affiliation(s)
- Bert Fraser-Reid
- Natural Products and Glycotechnology Research Institute Inc. (NPG), 595F Weathersfield Road, Pittsboro, NC 27312, USA
| | - J. Cristobal Lopez
- Instituto de Química Orgánica General (IQOG-CSIC), Juan de la Cierva 3, Madrid 28006, Spain
| | - Paloma Bernal-Albert
- Instituto de Química Orgánica General (IQOG-CSIC), Juan de la Cierva 3, Madrid 28006, Spain
| | - Ana M. Gomez
- Instituto de Química Orgánica General (IQOG-CSIC), Juan de la Cierva 3, Madrid 28006, Spain
| | - Clara Uriel
- Instituto de Química Orgánica General (IQOG-CSIC), Juan de la Cierva 3, Madrid 28006, Spain
| | - Juan Ventura
- Instituto de Química Orgánica General (IQOG-CSIC), Juan de la Cierva 3, Madrid 28006, Spain
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Abstract
Having access to mild and operationally simple techniques for attaining carbohydrate targets will be necessary to facilitate advancement in biological, medicinal, and pharmacological research. Even with the abundance of elegant reports for generating glycosidic linkages, stereoselective construction of α- and β-oligosaccharides and glycoconjugates is by no means trivial. In an era where expanded awareness of the impact we are having on the environment drives the state-of-the-art, synthetic chemists are tasked with developing cleaner and more efficient reactions for achieving their transformations. This movement imparts the value that prevention of waste is always superior to its treatment or cleanup. This review will highlight recent advancement in this regard by examining strategies that employ transition metal catalysis in the synthesis of oligosaccharides and glycoconjugates. These methods are mild and effective for constructing glycosidic bonds with reduced levels of waste through utilization of sub-stoichiometric amounts of transition metals to promote the glycosylation.
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Affiliation(s)
- Matthew J. McKay
- Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, United States
| | - Hien M. Nguyen
- Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, United States
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Ramamurty CVS, Ganney P, Rao CS, Fraser-Reid B. Ready Preparation of Furanosyl n-Pentenyl Orthoesters from Corresponding Methyl Furanosides. J Org Chem 2011; 76:2245-7. [DOI: 10.1021/jo1021376] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Changalvala V. S. Ramamurty
- Natural Products and Glycotechnology Research Institute, Inc., 595 F Weathersfield Road, Pittsboro, North Carolina 27312,United States
| | - Parimala Ganney
- Natural Products and Glycotechnology Research Institute, Inc., 595 F Weathersfield Road, Pittsboro, North Carolina 27312,United States
| | - C. Srinivas Rao
- CiVentiCHEM, P.O. Box 12041, Research Triangle Park, North Carolina 27709, United States
| | - Bert Fraser-Reid
- Natural Products and Glycotechnology Research Institute, Inc., 595 F Weathersfield Road, Pittsboro, North Carolina 27312,United States
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12
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Vidadala SR, Gayatri G, Sastry GN, Hotha S. Propargyl/methyl furanosides as potential glycosyl donors. Chem Commun (Camb) 2011; 47:9906-8. [DOI: 10.1039/c1cc13134f] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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13
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Liu C, Richards MR, Lowary TL. Synthesis and NMR spectroscopic analysis of acylated pentasaccharide fragments of mycobacterial arabinogalactan. Org Biomol Chem 2011; 9:165-76. [DOI: 10.1039/c0ob00423e] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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Zhang J, Amin AG, Hölemann A, Seeberger PH, Chatterjee D. Development of a plate-based scintillation proximity assay for the mycobacterial AftB enzyme involved in cell wall arabinan biosynthesis. Bioorg Med Chem 2010; 18:7121-31. [PMID: 20800502 DOI: 10.1016/j.bmc.2010.07.040] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2010] [Revised: 07/13/2010] [Accepted: 07/16/2010] [Indexed: 01/03/2023]
Abstract
A number of mycobacterial arabinosyltransferases, such as the Emb proteins, AftA, AftB, AftC, and AftD have been characterized and implicated to be involved in the cell wall arabinan assembly. These arabinosyltransferases are essential for the viability of the organism and are logically valid targets for developing new anti-tuberculosis agents. For instance, Ethambutol, a first line anti-tuberculosis drug, targets the Emb proteins involved in the formation of the arabinan of cell wall arabinogalactan. Among these arabinosyltransferases, the terminal β-(1→2) arabinosyltransferase activity has been associated with AftB. The predicted topology of AftB in Mycobacterium tuberculosis has 10 N terminal transmembrane domains and a C terminal hydrophilic domain similar to the Emb proteins. It has a conserved GT-C motif and is difficult to express. In a cell free assay, synthetic disaccharide, α-D-Araf-(1→5)-α-D-Araf-octyl, has been used as a substrate to explore the function of AftB. In our work, the disaccharide was synthesized in its pentenylated and biotinylated form, and the enzymatic product formed was identified as the β-(1→2) arabinofuranose adduct. When synthetic tri- and tetra-saccharides were used as substrates, a mixture of products containing both β-(1→2) and α-(1→5) linkages were formed. Therefore, the biotinylated disaccharide was selected to develop a scintillation proximity assay.
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Affiliation(s)
- Jian Zhang
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, USA.
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Tam PH, Lowary TL. Mycobacterial lipoarabinomannan fragments as haptens for potential anti-tuberculosis vaccines. CARBOHYDRATE CHEMISTRY 2010. [DOI: 10.1039/9781849730891-00038] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Pui-Hang Tam
- Alberta Ingenuity Centre for Carbohydrate Science and Department of Chemistry, The University of Alberta Gunning-Lemieux Chemistry Centre Edmonton AB, T6G 2G2 Canada
| | - Todd L. Lowary
- Alberta Ingenuity Centre for Carbohydrate Science and Department of Chemistry, The University of Alberta Gunning-Lemieux Chemistry Centre Edmonton AB, T6G 2G2 Canada
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Fraser-Reid B, López JC. Armed-disarmed effects in carbohydrate chemistry: history, synthetic and mechanistic studies. Top Curr Chem (Cham) 2010; 301:1-29. [PMID: 21120714 DOI: 10.1007/128_2010_105] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
This chapter begins with an account of the serendipitous events that led to the development of n-pentenyl glycosides (NPGs) as glycosyl donors, followed by the chance events that laid the foundation for the armed-disarmed strategy for oligosaccharide assembly. A key mechanistic issue for this strategy was that, although both armed and disarmed entities could function independently as glycosyl donors, when one was forced to compete with the other for one equivalent of a halonium ion, the disarmed partner was found to function as a glycosyl acceptor. The phenomenon was undoubtedly based on reactivity, but further insight came unexpectedly. Curiosity prompted an examination of how ω-alkenyl glycosides, other than n-pentenyl, would behave. Upon treatment with wet N-bromosuccinimide, allyl, butenyl, and hexenyl glucosides gave bromohydrins, whereas the pentenyl analog underwent oxidative hydrolysis to a hemiacetal. Although the answer was definitive, an in depth comparison of n-pentenyl and n-hexenyl glucosides was carried out which provided evidence in support of the transfer of cyclic bromonium ion between alkenes in a steady-state phenomenon. It was found that for two ω-alkenyl glycosides having a relative reactivity ratio of only 2.6:1, nondegenerate bromonium transfer enabled the faster reacting entity to be converted completely to product, while the slower reacting counterpart was recovered completely. This nuance suggests that in the armed/disarmed coupling, such a nondegenerate steady-state transfer is ultimately responsible for determining how the reactants are relegated to donor or acceptor roles.Development of chemoselective armed/disarmed coupling led to another phase in the sequence of serendipities. During experiments to glycosylate an acceptor diol, it was found that armed and disarmed donor's glycosylated different hydroxyl groups. This observation caused us to embark on studies of regioselective glycosylation. One of these studies showed that it is possible to activate selectively n-pentenyl orthoesters (NPOEs) over other n-pentenyl donors, and that this chemoselective process enables regioselective glycosylation. As a result, reaction partners can be so tuned that glycosylation of an acceptor with nine free hydroxyl groups by an n-pentenyl orthoester donor carrying two free hydroxyl groups is able to furnish a single product in 42% yield. Experiments such as the latter suggest that the donor favors a particular hydroxyl group, and/or that a particular hydroxyl favors the donor. Either option implies that the principle of reciprocal donor acceptor selectivity (RDAS) is in operation.Such examples of regioselective glycosylation provide an alternative to the traditional practice of multiple protection/deprotection events to ensure that the only free hydroxyl group among glycosyl partners is the one to be presented to the donor. By avoiding such protection/deprotections, there can be substantial savings of time and material - as well as nervous anxiety.
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Affiliation(s)
- Bert Fraser-Reid
- Natural Products and Glycotechnology Research Institute Inc. (NPG), Pittsboro, NC, USA,
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Smoot JT, Demchenko AV. Oligosaccharide synthesis: from conventional methods to modern expeditious strategies. Adv Carbohydr Chem Biochem 2009; 62:161-250. [PMID: 19501706 DOI: 10.1016/s0065-2318(09)00005-5] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- James T Smoot
- Department of Chemistry and Biochemistry, University of Missouri, St. Louis, MO 63121, USA
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20
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Harvey DJ. Analysis of carbohydrates and glycoconjugates by matrix-assisted laser desorption/ionization mass spectrometry: An update for 2003-2004. MASS SPECTROMETRY REVIEWS 2009; 28:273-361. [PMID: 18825656 PMCID: PMC7168468 DOI: 10.1002/mas.20192] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2008] [Revised: 07/07/2008] [Accepted: 07/07/2008] [Indexed: 05/13/2023]
Abstract
This review is the third update of the original review, published in 1999, on the application of matrix-assisted laser desorption/ionization (MALDI) mass spectrometry to the analysis of carbohydrates and glycoconjugates and brings the topic to the end of 2004. Both fundamental studies and applications are covered. The main topics include methodological developments, matrices, fragmentation of carbohydrates and applications to large polymeric carbohydrates from plants, glycans from glycoproteins and those from various glycolipids. Other topics include the use of MALDI MS to study enzymes related to carbohydrate biosynthesis and degradation, its use in industrial processes, particularly biopharmaceuticals and its use to monitor products of chemical synthesis where glycodendrimers and carbohydrate-protein complexes are highlighted.
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Affiliation(s)
- David J Harvey
- Department of Biochemistry, Oxford Glycobiology Institute, University of Oxford, Oxford OX1 3QU, UK.
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Bohn ML, Colombo MI, Rúveda EA, Stortz CA. Conformational and electronic effects on the regioselectivity of the glycosylation of different anomers of N-dimethylmaleoyl-protected glucosamine acceptors. Org Biomol Chem 2008; 6:554-61. [DOI: 10.1039/b715847e] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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22
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Bohn ML, Colombo MI, Pisano PL, Stortz CA, Rúveda EA. Differential O-3/O-4 regioselectivity in the glycosylation of α and β anomers of 6-O-substituted N-dimethylmaleoyl-protected d-glucosamine acceptors. Carbohydr Res 2007; 342:2522-36. [PMID: 17880931 DOI: 10.1016/j.carres.2007.08.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2007] [Revised: 08/15/2007] [Accepted: 08/16/2007] [Indexed: 11/21/2022]
Abstract
An assessment of the relative O-3/O-4 reactivities of both methyl alpha- and beta-d-glycosides of N-dimethylmaleoyl (DMM) d-glucosamine acceptors protected at O-6 with benzoyl (Bz), benzyl (Bn), and tert-butyldiphenylsilyl (TBDPS) groups is presented using per-O-benzoylated beta-d-galactofuranosyl and per-O-acetylated alpha-d-galactopyranosyl trichloroacetimidates as glycosyl donors. Using the former donor, the alpha anomer of the 6-O-benzoylated compound gave exclusive substitution at O-3, whereas the other two compounds with alpha-configuration kept this site as preferential. The beta anomer of the 6-O-benzoylated compound gave the same amounts of reaction products on O-3 and O-4, whereas the other beta analogs carried a more reactive O-4. The same reactions were carried out using as donor the less-reactive per-O-acetylated alpha-d-galactopyranosyl trichloroacetimidate. Although the same trend was found to occur, the O-4 was always relatively more reactive with the pyranosyl donor than with the furanosyl donor, when keeping the remaining factors constant. Furthermore, the beta anomers of the acceptor gave almost exclusive substitution at O-4. These observations confirm and extend the utility of these 'matching' donor and acceptor reactivities.
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Affiliation(s)
- María L Bohn
- Instituto de Química Orgánica y de Síntesis (CONICET-UNR), Facultad de Ciencias Bioquímicas y Farmacéuticas, Suipacha 531, 2000 Rosario, Argentina
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Anas S, Sajisha VS, Rajan R, Kumaran RT, Radhakrishnan KV. Ionic Liquid [bmim]PF6-Mediated Synthesis of 1,2-Orthoesters of Carbohydrates and the Glycosidation Reactions of 4-Pentenyl Orthoesters. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2007. [DOI: 10.1246/bcsj.80.553] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Litjens REJN, van den Bos LJ, Codée JDC, Overkleeft HS, van der Marel GA. The use of cyclic bifunctional protecting groups in oligosaccharide synthesis—an overview. Carbohydr Res 2007; 342:419-29. [PMID: 17007825 DOI: 10.1016/j.carres.2006.09.002] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2006] [Revised: 08/30/2006] [Accepted: 09/01/2006] [Indexed: 11/27/2022]
Abstract
A historical overview is presented on stereo-directing effects of cis- and trans-fused diol protective groups used on both donor and acceptor glycosides. Attention is focused on the use of cyclic carbonates and carbamates, diacetals and acetals and finally the special case of 1,2-O-orthoesters and 1,2-O-cyanoalkylidene functionalised residues.
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Affiliation(s)
- Remy E J N Litjens
- Leiden Institute of Chemistry, Leiden University, PO Box 9502, 2333CC Leiden, The Netherlands
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Synthesis of a 28-mer oligosaccharide core of Mycobacterial lipoarabinomannan (LAM) requires only two n-pentenyl orthoester progenitors. ACTA ACUST UNITED AC 2006. [DOI: 10.1016/j.tetasy.2006.09.008] [Citation(s) in RCA: 134] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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