ChemInform Abstract: Synthesis, NMR and Conformational Studies of Fucoidan Fragments. Part 1. Desulfated 2,3‐ and 3,4‐Branched Trisaccharide Fragments and Constituting Disaccharides.

Abstract

Synthesis, NMR and Conformational Studies of Fucoidan Fragments. Part 1. Desulfated 2,3-and 3,4-Branched Trisaccharide Fragments and Constituting Disaccharides. --(KHATUNTSEVA, ELENA A.; USTUZHANINA, NADEZHDA E.; ZATONSKII, GEORGIJ V.; SHASHKOV, ALEXANDER S.; USOV, ANATOLY I.; NIFANT'EV, NIKOLAY E.; J.

SYNTHESIS, NMR, AND CONFORMATIONAL STUDIES OF FUCOIDAN FRAGMENTS. III. EFFECT OF BENZOYL GROUP AT O-3 ON STEREOSELECTIVITY OF GLYCOSYLATION BY 3-O- AND 3,4-DI-O-BENZOYLATED 2-O-BENZYLFUCOSYL BROMIDES

“…6 In this paper we present the results of these reactions and theoretical calculations of plausible intermediates which demonstrate a larger influence on the efficiency of ␣-fucosylation of a benzoyl group at O-3 in a fucosyl donor than of that at O-4.…”

“…In the course of the synthesis of fucoidan fragments 6 we investigated the glycosylation of allyl 3,4-di-O-isopropylidene-␣-L-fucopyranoside 9 7 by 3-O-and 3,4-di-O-benzoylated 2-O-benzyl-L-fucopyranosyl bromides 6 and 7. 6 In this paper we present the results of these reactions and theoretical calculations of plausible intermediates which demonstrate a larger influence on the efficiency of ␣-fucosylation of a benzoyl group at O-3 in a fucosyl donor than of that at O-4.…”

The Synthesis of Blood Group Antigenic A Trisaccharide and Its Biotinylated Derivative

“…Despite numerous works devoted to the synthesis of oligosaccharides related to blood group antigens, there are only a few papers dedicated specifically to the synthesis of A trisaccharide derivatives [ 4 , 5 , 6 , 9 ]. Herein, we report on the assembly of spacered A trisaccharide 1a and its biotinylated derivative 1b , making use of the new galactose block 4 , which bears a set of convenient temporary protecting groups permitting selective liberation of HO-groups as well fucosyl donor 5 [ 18 , 19 ] and bicyclic 2-azido-2-deoxy-selenogalactoside 10 [ 20 ] containing stereo-controlling O-protecting groups, which favor the required α-(1,2- cis )-glycosylation. A bulky 4,6-O-(di-tert-butylsilylene)-protecting group at O-4 and O-6 was used to prevent the formation of undesirable β-glycosylation products [ 21 ] while a 3-O-benzoyl group was introduced to provide α-stereocontrol through remote anchimeric participation [ 22 ].…”

Fucoidan-Mimetic Glycopolymers : Synthesis and Biomedical Applications

“…Since 2000 this group has synthesized a broad series of mono-, di-, tri-, tetra-, hexa-, octa-, dodeca-, and hexadeca-α-L-fucosides (see Figure 1.2 C) bearing various glycosidic linkage patterns, branching, and sulfation degree and patterns [35][36][37][38][39][40][41][42]. Recently, this group synthesized a fragment from the brown seaweed Chordaria flagelliformis containing an α-L-fucofuranosyl unit (see Figure 1.2 D), which is unusual compared to the α-L-fucopyranosyl conformation that constitutes the vast majority of the L-fucosides found in fucoidan [43].…”

“…Recently, this group synthesized a fragment from the brown seaweed Chordaria flagelliformis containing an α-L-fucofuranosyl unit (see Figure 1.2 D), which is unusual compared to the α-L-fucopyranosyl conformation that constitutes the vast majority of the L-fucosides found in fucoidan [43]. The conformation of all of these fucosides have been carefully studied by NMR spectroscopy, but their biological properties have remained almost entirely unpublished [35][36][37][38][39][40][41][42][43]. As an exception a recent study showed that a fully sulfated α(1→3) octa-L-fucoside displayed no or decreased antibacterial phagocytic activity compared to fucoidan of larger molecular weights from natural sources [44].…”