Recent Trends in the Synthesis of O‐Glycosides of 2‐Amino‐2‐deoxysugars

Abstract

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SyntheticN-Acetyl-d-glucosamine Based Fully Branched Tetrasaccharide, a Mimetic of the Endogenous Ligand for CD69, Activates CD69+Killer Lymphocytes upon Dimerization via a Hydrophilic Flexible Linker

“…In contrast to the large number of studies devoted to the synthesis of linear oligosaccharides with β(1f4)linked 2-amino-2-deoxy-D-glucopyranose units, efficient and practical methods for the synthesis of analogous oligosaccharides with β(1f4)-linked 2-amino-2-deoxy-D-galactopyranose units remain scarce. Glycosylation 27 (22) promoted by silver perchlorate in the presence of silver carbonate gave a complex mixture of reaction products. Only few reports on disaccharide syntheses of this type have been published so far, and these used a glycosyl acceptor having the azido group as the masked amino function at the C(2) position and 2-deoxy-2-phthalimido-D-galactopyranosyl bromide as the glycosyl donor.…”

“…20 Moreover, we have shown that the complex pentaantennary bisecting undecasaccharide from egg white glycoprotein ovomucoid with the structure [GlcNAcβ1-2(GlcNAcβ1-4)(GlcNAcβ1-6)-ManR1-6][GlcNAcβ1-2(GlcNAcβ1-4)ManR13][GlcNA-cβ1-4]Manβ1-4GlcNAcβ1-4GlcNAc (OM, Chart 1), is one of the best ligands of natural origin identified so far. 22,23 Recently, we synthesized the branched homotrisaccharide β-D-GlcNAc-(1f3)[β-D-GlcNAc-(1f4)]-D-GlcNAc and found that its binding affinity for NK cell lectin receptors competed successfully with oligosaccharides of much greater complexity. This natural structure has thus provided an important paradigm for the development of smaller synthetic oligosaccharide mimetics that would be accessible for large scale synthesis and further potential use for in vivo experimental tumor therapies.…”

“…9,18 Yet another possibility is represented by de novo chemical syntheses of branched homooligosaccharides, which might afford new oligosaccharides rarely occurring in nature in pure form and in sufficient amounts. 22,23 Recently, we synthesized the branched homotrisaccharide β-D-GlcNAc-(1f3)[β-D-GlcNAc-(1f4)]-D-GlcNAc and found that its binding affinity for NK cell lectin receptors competed successfully with oligosaccharides of much greater complexity. 19 Here we aimed to identify oligosaccharide ligands useful for the modulation of activities of NK cells through their surface receptors, NKR-P1 and CD69.…”

Cu-Catalyzed Click Reaction in Carbohydrate Chemistry

“…164 However, despite the high regioselectivity of this reaction, a mixture of epimers 34 and 35 was observed in varying ratios based on the employed glycal substrate 33 (Scheme 12). 165 The prepared nitropyranoses 34 and 35 may find significance in preparation of numerous carbohydrate-based halides, thioglycosides, etc. 166−170 Likewise, 2-azido sugars can also be prepared by azidochlorination, 171 azidophenylselenation, 172,173 and diazo transfer reaction.…”

A top-down chemo-enzymatic approach towards N-acetylglucosamine-N-acetylmuramic oligosaccharides: Chitosan as a reliable template

“…(Holtje, 1998) The lack of pure PGN fragments, PGN derivatives or its mimetics, has strongly hampered the investigation of the relevance of the PGN structure in the metabolism of bacteria and the determination of its role in host disease.(L. H. Wang et al, 2006) The synthesis of NAG containing oligosaccharides, such as NAG-NAM disaccharides, (Berthelot et al, 2017;Shih, Chen, Cheng, Wong, & Cheng, 2011;Yang et al, 2011;Yang & Yu, 2014) presents several challenges, such as: the enantioselective establishment of the -(1,4)-glycosidic bond; the use of 2-acetamido-2deoxyglycosyl donors, that lead to formation of 1,2-O,N-oxazoline intermediates, (Arihara, Nakamura, & Hashimoto, 2005;Bongat & Demchenko, 2007;R. Enugala, Carvalho, Pires, & Marques, 2012;Stevenin, Boyer, & Beau, 2012) and the use of corresponding acceptors that are poor nucleophiles.…”