Synthesis of 3-aminopropyl glycosides of linear β-(1→3)-d-glucooligosaccharides

• 3-Aminopropyl β-(1→3)-oligoglucosides comprising 3–13 glucose units were prepared.
• A disaccharide donor block was used for the chain elongation.
• Chain assembly was fulfilled by selective 3-O-glycosylation of 2,3-diol acceptors.
• Chloroacetyl groups were used as temporary protections of the 2,3-diol system.

3-Aminopropyl glycosides of a series of linear β-(1→3)-linked d-glucooligosaccharides containing from 3 to 13 monosaccharide units were efficiently prepared. The synthetic scheme featured highly regioselective glycosylation of 4,6-O-benzylidene-protected 2,3-diol glycosyl acceptors with a disaccharide thioglycoside donor bearing chloroacetyl groups at O-2′ and -3′ as a temporary protection of the diol system. Iteration of the deprotection and glycosylation steps afforded the series of the title oligoglucosides differing in length by two monosaccharide units. A novel procedure for selective removal of acetyl groups in the presence of benzoyl ones consisting in a brief treatment with a large excess of hydrazine hydrate has been proposed.

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