摘要：Stereocontrolled syntheses of biotin-labeled oligosaccharide portions containing the non reducing end oligosaccharides of glycosphingolipids from Ascaris suum have been accomplished. Galα1→3GalNAcβ1→OR ( 1 ), Galβ1→3Galα1→3GalNAcβ1→OR ( 2 ), Galβ1→6Galα1→3GalNAcβ1→OR ( 3 ), Galβ1→6(Galβ1→3)Galα1→3GalNAcβ1→OR ( 4 ) and GlcNAcβ1→6Galβ1→6(Galβ1→3)Galα1→3GalNAcβ1→OR ( 5 ) (R = biotinylated probe) were synthesized by stepwise condensation ( 1 – 4 ) and block synthesis ( 5 ) using 5-(methoxycarbonylpentyl) 2- O -benzoyl-3- O -2-napthylmethyl-4,6- O -di- tert -butylsilylene-α-D-galactopyranosyl-(1→3)-4,6- O -benzylidene-2-deoxy-2-phthalimido-β-D-galactopyranoside ( 12 ) as a common precursor. Compound 12 was converted into two kinds of glycosyl acceptors and was condensed with suitable galactosyl donors, respectively.
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