Synthesis of N-glycopeptides and a neoglycoprotein.

O-(alpha-D-Glucopyranosyl)-(1----6)-O-beta-D-glucopyranosyl-(1----6)-1-N -(glycylglycylglycyl-L-seryl-L-leucyl-L-glutam-5-oyl)-alpha- D -glucopyranosylamine has been prepared, as a model of a derivative possibly present in the glomerular basement membrane of rats, by condensation of the corresponding L-glutamyl derivative of the trisaccharide with the pentapeptide in the presence of O,O-diethyl cyanophosphonate. Protective groups were removed by O-deacetylation, deethoxylation, and hydrogenolysis. The glutamyl derivative of the trisaccharide was also converted into the acyl azide which was condensed with bovine serum albumin to form a neoglycoprotein.