Concise chemical synthesis of the pentasaccharide repeating unit of the O-antigen from Escherichia albertii O2

Abstract

Total chemical synthesis of the pentasaccharide repeating unit of the O-antigen from Escherichia albertii O2 is accomplished by following a [3 + 2] strategy. The target pentasaccharide in the form of its 2-aminoethyl glycoside is particularly attractive as the free amine end can be coupled with suitable aglycon to make further glycoconjugate without affecting the anomeric stereochemistry. Phthalimido derivatives were used successfully as the precursor of the desired acetamido glucose moieties and ensured the 1,2-trans linkages.

Keywords: Diarrhoea; E. albertii; O-antigen; Thioglycoside activation; Total synthesis.