Nitrous acid deamination of amino-oligosaccharide alditols and their per-O-methylated derivatives

Per-O-methylated amino-oligosaccharide alditols prepared from lacto-N-tetraose, lacto-N-fucopentaose I, and the mixed populations of oligosaccharide chains from α₁-acid glycoprotein and hog gastric mucin have been used as model substrates to assess the scope of the reaction sequence, N-deacetylation-nitrous acid deamination followed by derivatization, in the fragmentation of complex amino-oligosaccharides. G.l.c.-mass spectrometry has been used as the major tool in the characterization of products.