Synthesis of 2,5-anhydro-(β- d-glucopyranosyluronate)- and (α- l-idopyranosyluronate)- d-mannitol hexa- O-sulfonate hepta sodium salt

Graphic Glycosidation of 2,5-anhydro-1,6-di- O-benzoyl- d-mannitol with methyl(2,3,4-tri- O-acetyl-α- d-glucopyranosyl-1- O-trichloroacetimidate)uronate in the presence of trimethylsilyl triflate afforded the corresponding 3- O-β-glycoside, which after deprotection was converted into its hexa- O-sulfate with DMF·SO 3 to give after treatment with sodium acetate and subsequent saponification of the methyl ester with sodium hydroxide the hepta sodium salt of 2,5-anhydro-3- O-(β- d-glucopyranosyl uronate)- d-mannitol hexa- O-sulfate. Glycosidation of the same acceptor with the α-thiophenylglycoside of methyl 2,4-di- O-acetyl-3- O-benzyl- l-idopyranosyl uronate in the presence of NIS/TfOH afforded the corresponding 3- O-α-glycoside in very low yield, therefore the α-thiophenylglycoside of 2- O-acetyl-2,4- O-benzylidene-3- O-benzyl- l-idopyranose was used as donor. The terminal hydroxymethyl group of the obtained disaccharide was subsequently oxidised with NaOCl/TEMPO and the obtained iduronic acid derivative was converted into the hepta sodium salt of 2,5-anhydro-3- O-(-α- l-idopyranosyluronate)- d-mannitol hexa- O-sulfonate with DMF·SO 3 and subsequent treatment with sodium acetate.