[Synthesis of the glycopeptide O-beta-D-galactopyranosyl-(1 to 3)-O-(2-acetamido-2-desoxy-alpha-D-galactopyranosyl)-(1 to 3)-L-serine and -L-threonine].
In the presence of silver carbonate-silver perchlorate and dichloromethane-toluene as solvent, 3,4,6-tri-O-acetyl-2-azido-2-deoxy-beta-D-galactopyranosyl chloride, and derivatives of L-serine and -L-serine and -L-threonine, gave, with high stereoselectivity, the benzyl esters of N-(benzyloxycarbonyl)-3-O-(3,4,6-tri-O-acetyl-2-azido-2-deoxy-alpha-D-galactopyranosyl)-L-serine (7) and -L-threonine (22), which were hydrogenolyzed and deblocked to give 3-O-(2-acetamido-2-deoxy-alpha-D-galactopyranosyl)-L-serine and -L-threonine, respectively, corresponding to the hapten of the Tn-antigen. Reduction of the azido group of 7, followed by selective O-deacetylation and benzylidenation, gave a derivative that was glycosylated with 2,3,4,6-tetra-O-acetyl-alpha-D-galactopyranosyl bromide to yield a disaccharide. A similar sequence of reactions, starting from 22, gave the L-threonine analog. Removal of the protecting groups from both compounds afforded O-beta-D-galactopyranosyl-(1 to 3)-O-(2-acetamido-2-deoxy-alpha-D-galactopyranosyl)-L-serine and -L-serine and -L-threonine, respectively, the hapten of the T-antigen.
D000955:Antigens, T-Independent; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D006020:Glycopeptides / Q000138:chemical synthesis*; D006241:Haptens; D007202:Indicators and Reagents; D012694:Serine; D013912:Threonine
D000955:Antigens, T-Independent; D006020:Glycopeptides; D006241:Haptens; D007202:Indicators and Reagents; D013912:Threonine; D012694:Serine
Synthese der glycopeptide O-beta-D-galactopyranosyl-(1 zu 3)-O-(2-acetamido-2-desoxy-alpha-D-galactopyranosyl)-(1 zu 3)-L-serin und -L-threonin.