PROCESS FOR THE PREPARATION OF ORGANIC OLIGOSACCHARIDES, CORRESPONDING TO FRAGMENTS OF NATURAL MUCO-POLYSACCHARIDES, OLIGOSACCHARIDES OBTAINED AND THEIR BIOLOGICAL APPLICATIONS

摘要

1. A process for the organic synthesis of oligosaccharides comprising [D-glucosamine] - [D-glucuronic acid or L-iduronic acid] enchainments, or the reverse, such as encountered in heparin or heparan-sulfate, comprising : - using in a glycosylation reaction two compounds constituted or terminated respectively by A unit or D-glucosamine structure, and U unit of D-gluronic acid or L-iduronic acid structure, one of the units A or U being an alcohol in which the -OH group of the alcohol function occupies position 4, the other unit having an activated anomeric carbon, substituted by a reactive group compatible with the other groups présent on the units ; all the position of A and U excepted the one whose anomeric carbon is activated or the one occupied by the -OH group of the alcohol function, bearing either amino groups or carboxyl groups, or precursors of such groups, or again -OH groups, said groups occupying determined positions, the amino and carboxyl groups, when they are present, being respectively blocked by protective groups of amino and carboxyl functions, the -OH groups being blocked by at least two types of protective groups, sequencially removable while enabling the introduction of given groups at given positions, then the liberation of -OH groups to in other positions, - repeating, if desired, the glycosylation step to elongate the oligosaccharidic chain, - sequencially removing the protective groups of -OH groups by introducing desired substitution groups in specific positions, then making free the -OH groups in other specific positions as well as the amino and carboxyl groups, provided that the establishment of the interglycoside linkage does not lead to the obtention of a disaccharide with a [2-N-sulfate or (2-N-acetyl)-6-O-sulfate-D-glucosamine] - [methyl-D-glucuronic acid] structure.