Synthesis of the spacer-containing beta-D-GalpNAc-(1-->4)-beta-D- GlcpNAc-(1-->3)-alpha-D-Galp moiety, representing the non-fucosylated backbone trisaccharide of the glycocalyx glycan of the parasite Schistosoma mansoni.
The chemical synthesis of beta-D-GalpNAc-(1-->4)-beta-D-GlcpNAc- (1-->3)-alpha-D-Galp-(1-->O)-(CH2)5NH2 is described. This structure represents the nonfucosylated backbone trisaccharide of the glycocalyx glycan of the cercarial stage of the parasite Schistosoma mansoni. Synthesis of the trisaccharide was achieved via a stepwise coupling approach. 5-Azidopentyl 4-O-acetyl-2,6-di-O-benzyl-alpha-D-galactopyranoside was condensed with ethyl 6-O-benzyl-2-deoxy-3,4-di-O-dimethylisopropylsilyl- 2-phthalimido-1-thio-beta-D-glucopyranoside, using N-iodosuccinimide and silver trifluoromethanesulfonate as a catalyst system, followed by the removal of the silyl ether groups to afford a disaccharide acceptor. Coupling of ethyl 4,6-di-O-acetyl-3-O- allyloxycarbonyl-2-deoxy-2-phthalimido-1-thio-beta-D-galactopyrano side to the disaccharide acceptor, using methylsulfenyl bromide and silver trifluoromethanesulfonate as a catalyst system, gave a protected trisaccharide. Deprotection of this compound yielded the target structure.
Halkes
K M
KM
Bijvoet Center, Department of Bio-Organic Chemistry, Utrecht University, The Netherlands.
Lefeber
D J
DJ
Fransen
C T
CT
Kamerling
J P
JP
Vliegenthart
J F
JF
D000818:Animals; D000953:Antigens, Protozoan / Q000737:chemistry*; D002240:Carbohydrate Sequence; D019276:Glycocalyx / Q000737:chemistry*; D008969:Molecular Sequence Data; D011134:Polysaccharides / Q000737:chemistry*; D012550:Schistosoma mansoni / Q000737:chemistry*; D014312:Trisaccharides / Q000138:chemical synthesis*
D000953:Antigens, Protozoan; D011134:Polysaccharides; D014312:Trisaccharides