Loss of O-methyl groups from methylated 2-amino-2-deoxy-D-glucitol and -D-galactitol derivatives under acidic conditions used during the analysis of glycoproteins

Abstract

In the acetolysis/hydrolysis procedure (1), usually employed for the cleavage of permethylated oligosaccharides isolated from glycoproteins, O-demethylation of C-1 of the substituted, terminal hexosaminitol derivative occurs. Upon acetylation of the hydrolysate this yields a 1-O-acetyl-2-(N-methylacetamido)-2-deoxy-hexitol derivative and not, as suggested (2),a 2-acetylacetamido-2-deoxy-hexitol derivative.