The exploration of the molecular and structural basis for the amino group of the glucosamine residue (2b-position) and a free amino group at the 6b-position. The 6b-amino group was sorting of GPI-anchored proteins is based on labeled partial structures of GPIЈs which can be incorporated into the GPI used for the ligation of the 3-(7-nitrobenzofurazan-4-yl)aminopropanoyl group as a fluorescent label, the 5-azido-2-anchor biosynthesis and cellular transport systems. To this end, from mannosyl donor 6 and the D-glucosaminyl-(1Ǟ6)-nitrobenzoyl and 4-azidophenylaminothiocarbonyl groups as photolabels, and the 4-azido-2-hydroxybenzoyl group as a D-myo-inositol derivative 7 as acceptor, the pseudotrisaccharide 8 was prepared. Compound 8 was transformed radiolabel after the introduction of radioactive iodine by an electrophilic aromatic substitution. Thus, after acid-catalyzed into the GPI partial structures 5a,b which contain the pseudotrisaccharide ligated to two different phosphatidyl removal of the protective groups, the unprotected target molecules 1-4 were obtained. residues. Compounds 5a,b have Boc protection at the 2-