Hydrazinolysis-N-reacetylation of glycopeptides and glycoproteins. Model studies using 2-acetamido-1-N-(L-aspart-4-oyl)-2-deoxy-beta-D-glucopyranosy lamine.

2-Acetamido-1-N-(L-aspart-4-oyl)-2-deoxy-beta-D-glucopyranosyla mine (1) was used as a model glycopeptide to study the hydrazinolysis-N-reacetylation procedure. The major, initial product was the beta-acetohydrazide derivative of 2-acetamido-2-deoxy-D-glucose (2) which gave 2-acetamido-2-deoxy-D-glucose (5) after exposure to acidic conditions. Very mild conditions of hydrolysis of 2 gave a 75-80% overall yield of 5 from 1 after the hydrazinolysis-N-reacetylation procedure. Several other minor compounds were detected which were not converted into 5 upon mild acid hydrolysis, indicating that 20-25% of product cannot be recovered as 5 at the reducing end of oligosaccharides.