Synthesis of the sialic acid-containing tetrasaccharide repeating unit corresponding to the cell wall O-antigen of Escherichia coli O131 strain.

A concise synthetic strategy have been developed for the synthesis of the sialic acid-containing tetrasaccharide repeating unit of the cell wall O-antigen of Escherichia coli (E. coli) O131 strain using regio- and stereoselective (2 → 6)-α-glycosylations of judiciously protected sialic acid thioglycoside derivatives. Perchloric acid supported over silica (HClO ₄ -SiO ₂ ) in combination with N-iodosuccinimide (NIS) has been used in the stereoselective activation of thioglycoside derivatives as well as used as a solid acid for the functional group modifications. Appropriate stereoselectivity was achieved in the glycosylation steps involved in the synthetic strategy.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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