194858-02-1Relevant academic research and scientific papers
Synthesis of oligosaccharides designed to form micelles, corresponding to structures found in ovarian cyst fluid
Buskas, Therese,Konradsson, Peter
, p. 25 - 51 (2007/10/03)
The syntheses of α-D-GlcpNAc-(1 →4)-β-D-Galp-(1→4)-β-D-GlcNAc-(1→O)-(CH2)15CH3 (1) and fragments thereof, corresponding to structures found in human ovarian cyst fluid, are described. Silver triflate promoted coupling of 3.4,6-tri-O-acetyl-2-azido-2-deoxy-β-D-glucopyranosyl bromide (12) and galactose acceptor (11) gave a disaccharide donor (13), which was readily transformed into the corresponding bromoderivative 18. For the synthesis of disaccharide β-D-Galp-(1 →4)-D-GlcNAc, several differently protected glucosamine acceptors were prepared. It was found that cetyl alcohol needed to be introduced after the formation of the β-galactoside bond. Glycosylation of pent-4-enyl 3,6-di-O-benzyl-2-deoxy-2-tetrachlorophthalimido-β-D-glucopyranoside (30) with (3,4,6-tri-O-acetyl-2-azido-2-deoxy-α-D-glucopyranosyl)-(1 →4)-2,3,6-tri-O-benzoyl-α-D-galactopyranosyl bromide (18) by use of silver triflate as promoter gave the desired trisaccharide 31. Finally 31 was transformed via coupling to the long alkyl chain aglycon and deprotection into the title compound 1.
Synthesis of the Tetrasaccharide Repeating Unit of the K-antigen from Klebsiella Type 57
Sarbajna, Sumita,Roy, Nirmolendu
, p. 400 - 408 (2007/10/03)
Starting from D-galactose and D-mannose two disaccharide blocks, namely 2-(trimethylsilyl)-ethyl 2,3,4,6-tetra-O-benzyl-α-D-mannopyranosyl-(1->4)-6-O-(4-methoxybenzyl)-β-D-galactopyranoside and ethyl 2,3,4,6-tetra-O-benzyl-α-D-mannopyranosyl-(1->3)-4-O-acetyl-2,6-di-O-benzoyl-1-thio-β-D-galactopyranoside, were synthesized which were then allowed to react, in the presence of dimethylamino(methylthio)sulfonium triflate to give a tetrasaccharide derivative.This compound was converted to 2-(trimethylsilyl)ethyl 2,3,4,6-tetra-O-benzyl-α-D-mannopyranosyl-(1->3)-4-O-acetyl-2,6-di- O-benzoyl-β-D-galactopyranosyl-(1->3)-4)>-tert-butyl (2-O-acetyl-β-D-galactopyranosid)uronate which, on treatment with sodium methoxide followed by hydrogenolysis, afforded the methyl uronate of the tetrasaccharide repeating unit of the K-antigen from Klebsiella type 57. - Keywords: synthesis; Klebsiella type 57; tetrasaccharide repeating unit.
Synthesis of a hexasaccharide corresponding to a porcine zona pellucida fragment that inhibits porcine sperm-oocyte interaction in vitro
Spijker, Nynke M.,Keuning, Cor A.,Hooglugt, Mariska,Veeneman, Gerrit H.,Van Boeckel, Constant A. A.
, p. 5945 - 5960 (2007/10/03)
The synthesis of hexasaccharide 1, [galβ(1-4)GlcNAc[6OSO3]β(1-3)Galβ(1-4)GlcNAcβ(1-3)Galβ(1-3)GalNA cα-O(CH2)3NH2], which corresponds to a porcine zona pellucida fragment that inhibits porcine sperm-oocyte interaction, is described. Compound 1 was obtained from fully protected hexasaccharide 2, which was in turn constructed from protected Galβ(1-3)GalNAc disaccharide 5, containing an α-linked 3-azidopropyl spacer, and from lactosamine derivatives 3 and 4. Disaccharide 3 and 4 were prepared by coupling of selenophenyl glycoside 6 with glycosyl acceptors containing anomeric thioethyl groups. NIS/TfOH promoted coupling of disaccharide 4 with 5 afforded 29, which was transformed into the tetrasaccharide acceptor 30 by selective removal of the levulinoyl group. Glycosylation of 30 with 3 afforded protected hexasaccharide 2. Removal of the phthalimido groups, acetylation, followed by selective removal of the allyl group and sulphation, and finally complete deprotection afforded hexasaccharide 1.
