174077-02-2Relevant academic research and scientific papers
Chemoenzymatic Synthesis of Asymmetrical Multi-Antennary N-Glycans to Dissect Glycan-Mediated Interactions between Human Sperm and Oocytes
Chinoy, Zoeisha S.,Friscourt, Frédéric,Capicciotti, Chantelle J.,Chiu, Philip,Boons, Geert-Jan
, p. 7970 - 7975 (2018)
Complex N-glycans of glycoproteins of the zona pellucida (ZP) of human oocytes have been implicated in the binding of spermatozoa. The termini of these unusual bi-, tri-, and tetra-antennary N-glycans consist of the tetrasaccharide sialyl-Lewisx (SLex), which was previously identified as the minimal epitope for sperm binding. We describe here the chemoenzymatic synthesis of highly complex triantennary N-glycans derived from ZP carrying SLex moieties at the C-2 and C-2′ arm and a sialyl-Lewisx-Lewisx (SLex–Lex) residue at the C-6 antenna and two closely related analogues. The compounds were examined for their ability to inhibit the interaction of human sperm to ZP. It was found that the SLex–Lex moiety is critical for inhibitory activity, whereas the other SLex moieties exerted minimal effect. Further studies with SLex–Lex and SLex showed that the extended structure is the more potent inhibitor. In addition, trivalent SLex–Lex and SLex were prepared which showed greater inhibitory activity compared to their monovalent counterparts. Our studies show that although SLex can inhibit the binding of spermatozoa, presenting this epitope in the context of a complex N-glycan results in a loss of inhibitory potential, and in this context only SLex–Lex can make productive interactions. It is not the multivalent display of SLex on a multi-antennary glycan but the presentation of multiple SLex–Lex on the various glycosylation sites of ZP that accounts for high avidity binding.
Synthesis of Neisseria meningitidis X capsular polysaccharide fragments
Morelli, Laura,Lay, Luigi
, p. 166 - 184 (2013/01/16)
Serotype X of Neisseria meningitidis bacterium (Men X) recently emerged as a substantial threat to public health. Since anti-meningococcal vaccines currently available or under investigation do not contain antigenic components of Men X capsular polysaccha
Synthesis of Carbon-Bridged N-Acetyl-C-lactosamine and derivatives
Eisele, Thomas,Ishida, Hideharu,Hummel, Gerd,Schmidt, Richard R.
, p. 2113 - 2122 (2007/10/03)
4-C-Formyl-2-azidoglucopyranoside 12a, required for N-acetyl-C-lactosamine synthesis as electrophile, was obtained from thexyldimethylsilyl 2-azido-2-deoxy-glucopyranoside 3 via readily available 4-O-unprotected 6a and then 4-C-methylene derivative 8a in overall seven steps.Alternatively, regioselective silylation of 3 with tert-butyldimethylsilyl chloride gave 4-O-unprotected 6b which was transformed by a similar reaction sequence into 12a.In order to circumvent a Wittig reaction, 6a was transformed into triflate 13 the reaction of which with 4-C-cyano derivative 14 followed by reduction with DIBAH and base-catalyzed isomerization also afforded 12a.Reaction of 12a with 1-C-lithiated 2-phenylsulfinyl-D-galactal 15 as nucleophile furnished C-disaccharide intermediates 16a and 16b as diastereoisomers.Ensuing removal of the phenylsulfinyl group with Raney nickel and diastereospecific 2b-hydrogen and 3b-hydroxy transfer afforded β(1->4)-connected N-acetyl-C-lactosamines 19a and 19b; their structures were deduced from derivatives 20a, b and 21a, b on the basis of 1H-NMR data.Hydrogenolytic O-debenzylation of 19b afforded hydroxymethylene-bridged N-acetyl-C-lactosamine 2b'. - Keywords: C-Saccharide; C-Glycosides; C-Lactosamine; 1-Lithiogalactal; Vinillithium; Branched sugars; Glucosamine, C-formyl
