Synthesis of Multivalent Neoglyconjugates of MUC1 by the Conjugation of Carbohydrate-centered, Triazole-linked Glycoclusters to MUC1 Peptides Using Click Chemistry

The efficient synthesis of multivalent neoglycoconjugates of MUC1 is reported, which utilizes Cu(I)-catalyzed azide-alkyne 1,3-dipolar cycloaddition (CuACC) of azide-functionalized GlcNAc-centered neoglycotetrasaccharide clusters to the MUC1 peptide sequence that was equipped with a propargylglycine residue for "click chemistry". In turn the azido-GlcNAc-centered neoglycoclusters were assembled by reaction of a GlcNAc core containing peripheral propargyl functionalities with an appropriate azido-functionalized monosaccharide. The resulting suitably substituted tetrasaccharyl triazole cluster can be easily appended to a range of acetylene-functionalized peptides to produce neoglycoconjugates of biologically important glycopeptides. As proof of principle, the click neoglycoclusters prepared herein were ligated to the MUC1 peptide sequence.