title: Linear synthesis of the hexasaccharide related to the repeating unit of the O-antigen from Shigella flexneri serotype 1d (I: 7,8).
abstract: Total synthesis of the hexasaccharide repeating unit of the O-antigen from Shigella flexneri serotype 1d (I: 7,8), α-D-Glcp-(1→3)-α-L-Rhap-(1→2)-α-L-Rhap-(1→3)-α-L-Rhap-(1→3)-[α-D-Glcp-(1→4)]-β-D-GlcpNAc, is reported by following a linear strategy. The target hexasaccharide was synthesized by sequential glycosylations of suitably protected monosaccharide derivatives prepared from commercially available monosaccharides through rational protecting group manipulations. Stereoselective glycosylations were accomplished by the activation of thioglycoside using N-iodosuccinimide and H2SO4-silica. The use of H2SO4-silica in place of traditional promoters like TfOH or TMSOTf was proved to be a better option for the NIS-mediated thioglycoside activation.
authors.affiliation: Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur 741246, India.
authors.forename: Ankita
authors.initials: A
authors.lastname: Mitra
authors.affiliation: Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur 741246, India. Electronic address: sugarnet73@hotmail.com.
authors.forename: Balaram
authors.initials: B
authors.lastname: Mukhopadhyay
mesh_terms: D002236:Carbohydrate Conformation; D019081:O Antigens / Q000737:chemistry* / Q000276:immunology; D009844:Oligosaccharides / Q000138:chemical synthesis* / Q000737:chemistry* / Q000276:immunology; D012763:Shigella flexneri / Q000737:chemistry* / Q000276:immunology
chemical_list: D019081:O Antigens; D009844:Oligosaccharides
keywords: Chloroacetate; Glycosylation; H(2)SO(4)-silica; O-antigen; Oligosaccharide; Thioglycoside