Synthesis of mucin O-glycan core structures as their p-nitro- and p-aminophenyl glycosides

For the investigation of glycosidases, and for the construction of glycan arrays the p-nitrophenyl- and p-aminophenyl glycosides of mucin O-glycan core structures 1-7 and the 2,6-ST-antigen have been chemically synthesized using d-galactose as a precursor for GalNAc residues. GlcNAc residues have partly been introduced using a 4,6-di-O-benzoyl-2,3-N,O-oxazolidinone-protected donor, which allowed deprotection of the formed di- and tri-saccharides in one step using sodium methoxide.