The Carbohydrate–protein Linkage in Glycoproteins: Part I. The Syntheses of Some Model Substituted Amides and an L -Seryl- D -Glucosaminide

The syntheses of N-L-seryl-D-glucosamine, N-glycyl-D-glucosamine, N-L-glutamyl-D-glucosamine, and 1-O-β-L-seryl-N-acetyl-D-glucosaminide are described. These D-glucosamine derivatives may result from the fragmentation of some glycoproteins. The chemical properties of these compounds indicate that N-peptides are relatively stable in acid solution but unstable in neutral and alkaline solution. The seryl glucosaminide is relatively stable in alkaline solution but is hydrolyzed by acid.