SYNTHESIS OF 8 GLYCOSIDES OF HEXASACCHARIDE FRAGMENTS REPRESENTING THE TERMINUS OF THE O-POLYSACCHARIDE OF VIBRIO-CHOLERAE O-1, SEROTYPE INABA AND OGAWA, BEARING AGLYCONS SUITABLE FOR LINKING TO PROTEINS

The title substances were prepared from intermediate, fully acetylated alpha-trimethylsilylethyl (SE) glycosides. The latter were assembled in a blockwise manner, using as the glycosyl donor the alpha-glycosyl chloride of a disaccharide bearing two 4-azido-4-deoxy functions. Next , the azido groups in the assembled hexasaccharides were converted to the corresponding amines, and these were acylated with 4-O-benzyl-3-de oxy-L-glycero-tetronic acid in the presence of a water-soluble carbodi imide. The SE glycosides were then transformed to glycosyl imidates, a nd these were coupled with methyl 6-hydroxyhexanoate or methyl 2-(2-hy droxyethylthio)propionate. The aglycons in the glycosides thus obtaine d were then converted to the corresponding carboxylic acids or acyl hy drazides. Such compounds are suitable for linking to proteins to obtai n neoglycoproteins.