508194-14-7Relevant academic research and scientific papers
Exploring the Structural Space of the Galectin-1–Ligand Interaction
Bertleff-Zieschang, Nadja,Bechold, Julian,Grimm, Clemens,Reutlinger, Michael,Schneider, Petra,Schneider, Gisbert,Seibel, Jürgen
, p. 1477 - 1481 (2017/08/10)
Galectin-1 is a tumor-associated protein recognizing the Galβ1-4GlcNAc motif of cell-surface glycoconjugates. Herein, we report the stepwise expansion of a multifunctional natural scaffold based on N-acetyllactosamine (LacNAc). We obtained a LacNAc mimeti
Linear synthesis of the branched pentasaccharide repeats of O-antigens from Shigella flexneri 1a and 1b demonstrating the major steric hindrance associated with type-specific glucosylation
Hargreaves, Jason M.,Le Guen, Yann,Guerreiro, Catherine,Descroix, Karine,Mulard, Laurence A.
, p. 7728 - 7749 (2015/01/08)
Shigella flexneri serotypes 1b and 1a are Gram-negative enteroinvasive bacteria causing shigellosis in humans. The O-antigen from S. flexneri 1b is a {→2)-[3Ac/4Ac]-α-l-Rhap-(1→2)-α-l-Rhap-(1→3)-[2Ac]-α-l-Rhap-(1→3)-[α-d-Glcp-(1→4)]-β-d-GlcpNAc-(1→}n branched polysaccharide ({AcABAcC(E)D}n). It is identical to that from S. flexneri 1a, except for the 2C-acetate. A concise synthesis of the disaccharide ED, trisaccharides AcC(E)D and C(E)D, tetrasaccharides BAcC(E)D and BC(E)D, and pentasaccharides ABAcC(E)D and ABC(E)D is described starting from a 2-N-acetyl-d-glucosaminide acceptor and using the imidate glycosylation chemistry. The E residue was efficiently introduced via a potent stereoselective [E + D] coupling. In contrast, harsh conditions and appropriate tuning of the donor were required for a high yielding [C + ED] glycosylation. Irrespective of the level of steric bulk at residue C, glycosylation at O-3D of the ED acceptor generated a major change of conformation of the D residue within the obtained C(E)D trisaccharide, as attested by NMR data. Proper manipulation of the constrained C(E)D trisaccharide was necessary to proceed with the stepwise chain elongation at O-3C of an acceptor having the 2C-O-acetyl already in place. The protected intermediates went through a one- to three-step deprotection sequence to give the propyl glycoside targets, as portions of the O-antigens from both S. flexneri 1a and 1b. Protecting group removal was clearly associated with conformational relief, yielding oligosaccharides, for which NMR data were consistent with a 4C1 conformation for the 3,4-di-O-glycosylated residue D, as in the native bacterial polymers.
Stereoselective dihydroxylation reaction of alkenyl β- D -hexopyranosides: A methodology for the synthesis of glycosylglycerol derivatives and 1-O-Acyl-3-O-β- D -glycosyl-sn-glycerol analogues
Vega-Perez, Jose M.,Palo-Nieto, Carlos,Perinan, Ignacio,Vega-Holm, Margarita,Calderon-Montano, Jose M.,Lopez-Lazaro, Miguel,Iglesias-Guerra, Fernando
scheme or table, p. 1237 - 1252 (2012/04/10)
A variety of new glycosylglycerol derivatives have been prepared by stereoselective dihydroxylation of a range of alkenyl β-D-hexopyanosides under Donohoe's conditions. We have studied the relationship between the diastereoisomeric excess and the structural features of the precursor (sugar and alkenyl moieties). The stereochemical yields demonstrated that the presence of a hydrogen-bond donor group (OH, NHAc) at the 2-position of the sugar moiety is required to obtain high levels of stereofacial discrimination. New 1-O-acyl-3-O-β-D-glycosyl-sn-glycerol analogues were obtained by functionalisation of the primary hydroxy group with a fatty acid. Preliminary cytotoxic activity assays of both glycosylglycerol and glycoglycerolipid analogues are also presented. An efficient asymmetric dihydroxylation reaction of alkenyl β-D-hexopyranoside derivatives is described. New glycosylglycerol and glycoglycerolipid analogues have been synthesised by this methodology. Preliminary cytotoxic activity assays are presented. Copyright
Stereoselective synthesis of epoxyalkyl glycoside precursors of glycosyl glycerol analogues from alkenyl glycosides of N-acetyl-D-glucosamine derivatives
Vega-Perez, Jose M.,Candela, Jose I.,Blanco, Eugenia,Iglesias-Guerra, Fernando
, p. 2471 - 2483 (2007/10/03)
The synthesis of epoxyalkyl glycoside derivatives of N-acetyl-D-glucosamine is described. Epoxidation of the corresponding alkenyl glycosides with m-CPBA took place with different stereoselectivity depending on the nature of the unsaturated system and the protecting groups on the sugar moiety. The configuration of the newly formed stereogenic centres has been confirmed unequivocally by chemical correlation.
1,3,4,6-Tetra-O-acetyl-2-chloroacetamido-2-deoxy-β-D-glucopyranose as a glycosyl donor in syntheses of oligosaccharides
Dasgupta, Falguni,Anderson, Laurens
, p. 239 - 255 (2007/10/02)
1,3,4,6-Tetra-O-acetyl-2-chloroacetamido-2-deoxy-β-D-glucopyranose was tested as a glycosyl donor for oligosaccharide synthesis via ferric chloride-catalyzed coupling reaction.Glycosyl acceptors tried (6 in all) were O-benzyl-protected D-galactosides having free OH groups at positions 3 and 4, respectively, and similarly protected glycosides of D-glucose and 2-acetamido-2-deoxy-D-glucose unsubstituted on O-4.Existing syntheses of all the acceptors were improved, in four instances by exploitation of Garegg and Hultberg's cyanoborohydride procedure for the conversion 4,6-O-benzylidene -> 6-O-benzyl .Good to excellent yields of β-linked disaccharides were obtained from the galactoside and glucoside acceptors, but with allyl 2-acetamido-3,6-di-O-benzyl-2-deoxy-α-D-glucopyranoside, stereoselectivity was lost (α:β-ratio 1:2).Allyl and benzyl 2-acetamido-3,6-di-O-benzyl-2-deoxy-β-D-glucopyranosides gave, respectively, the allyl and benzyl β-glycosides of the donor as major products.A mechanism is proposed for this transglycosidation reaction.The N-chloroacetyl groups in the disaccharide products were readily converted into N-acetyl by reduction with zinc-acetic acid.
