The preparation of a partially protected heptasaccharide-asparagine intermediate for glycopeptide synthesis.
The heptasaccharide O-alpha-D-mannopyranosyl-(1----6)-O-[alpha-D-mannopyranosyl-(1----3)]-O- alpha-D-mannopyranosyl-(1----6)-O-[alpha-D-mannopyranosyl-(1----3)]-O-be ta- D-mannopyranosyl-(1----4)-O-(2-acetamido-2-deoxy-beta-D-glucopyranosyl)- (1----4)-2-acetamido-2-deoxy-D-glucopyranose, isolated from the urine of swainsonine-intoxicated sheep, was peracetylated and was converted into the glycosyl azide by three alternative procedures, the most successful of which was formation of peracetyl oxazoline by treatment with trimethylsilyl trifluoromethanesulfonate, followed by treatment with trimethylsilyl azide. Reduction of the glycosyl azide in the presence of Lindlar catalyst gave the glycosylamine derivative, which was coupled with 1-benzyl N-fluoren-9-ylmethoxycarbonyl-L-aspartate to yield a protected glycosylasparagine. The benzyl ester group was easily removed by hydrogenolysis to form an intermediate suitable for glycopeptide synthesis.
Nakabayashi
S
S
Department of Biological Chemistry, Harvard Medical School, Boston, Massachusetts.
Warren
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CD
Jeanloz
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RW
D001216:Asparagine; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D006020:Glycopeptides / Q000138:chemical synthesis*; D007202:Indicators and Reagents; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D009844:Oligosaccharides / Q000138:chemical synthesis*; D009904:Optical Rotation
D006020:Glycopeptides; D007202:Indicators and Reagents; D009844:Oligosaccharides; D001216:Asparagine