346435-08-3Relevant academic research and scientific papers
Synthesis of Glucuronoxylan Hexasaccharides by Preactivation-Based Glycosylations
B?hm, Maximilian,Madsen, Robert,Underlin, Emilie N.,d'Errico, Clotilde
supporting information, (2020/05/16)
The synthesis of two glucuronoxylans is described, which both consist of a pentaxylan backbone and a glucuronic acid linked to the 2 position in the fourth xylose residue from the reducing end. The two target molecules differ in the 4 position of the glucuronic acid where one is unsubstituted while the other contains a methyl ether. The pentaxylan backbone is assembled in four glycosylation reactions with phenyl thioglycoside donors. The couplings are performed by preactivation of the donor with in-situ-generated p-nitrobenzenesulfenyl triflate prior to addition of the acceptor. The glucuronic acids are then attached by Koenigs-Knorr glycosylations followed by deprotections. The syntheses employ a total of 8 steps from monosaccharide building blocks and afford the two glucuronoxylans in 12 and 15 % overall yield. The hexasaccharide products are valuable substrates for investigating the activity and specificity of glucuronoxylan-degrading enzymes.
Synthesis of uronic acid-containing xylans found in wood and pulp
Oscarson,Svahnberg
, p. 873 - 879 (2007/10/03)
Two uronic acid-containing trisaccharides, (4-deoxy-β-L-threo-hex-4-enopyranosyluronic acid)- and (4-O-methyl-α-D-gluropyranosyluronic acid)-(1→2)-β-D-xylopyranosyl-(1→4)-D-xylopyranose, found in enzyme hydrolysates from pulp are synthesised. A common dixyloside 2′-OH acceptor, p-methoxyphenyl[3,4-O-(2′,3′-dimethoxybutane-2′,3′- diyl)-β-D-xylopyranosyl]-(1→4)-2,3-di-O-benzoyl-β- D-xylopyranoside, is constructed and coupled with two glucuronate thioglycoside donors differently substituted in the 4-position, O-methyl and O-mesyl, respectively, to give trisaccharides. DMTST as promoter in diethyl ether gives exclusively the α-linked products in high yield. Treatment of the 4″-O-mesyl trisaccharide with DBU then gives the α,β-unsaturated uronic acid derivative. The protection pattern introduced in the acceptor allows continued synthesis of larger oligosaccharides. Removal of the butanedione acetal produces 3′,4′-acceptors, and the p-methoxyphenyl glycoside can be transformed into various glycosyl donors, e.g. thioglycosides and sugar halides. Complete deprotection gives the two target reducing trisaccharides.
