SYNTHESIS AND SEMISYNTHESIS OF SOME STRUCTURAL ELEMENTS OF OLIGO-MANNOSE TYPE N-GLYCOPROTEINS

For the construction of N-glycoprotein glycan chains, valuable potenti al glycosyl donors, pha-D-mannopyranosyl-(1-->2)-alpha-D-mannopyranose octaacetate (19) and pha-D-mannopyranosyl-(1-->2)-alpha-D-mannopyrano se undecaacetate (20) were obtained in gram-scale by the acetylation a nd subsequent partial acetolysis of baker's yeast, without the isolati on of mannan. The acetolytic products were investigated by matrix-assi sted laser desorption/ionization time-of-flight (MALDI-TOF) mass spect rometry. Octaacetates of mannobiose (1-->3) (11) and (1-->6) (17) were chemically synthesized.