title: Concise synthesis of the tetrasaccharide repeating unit of the O-polysaccharide isolated from Edwardsiella tarda PCM 1156 strain.
abstract: A convergent strategy has been developed for the synthesis of the tetrasaccharide repeating unit of the O-antigen from Edwardsiella tarda PCM 1156. Sequential glycosylations of a series of rationally protected monosaccharide intermediates were achieved either by the activation of thioglycosides using N-iodosuccinimide (NIS) in conjunction with H2SO4-silica or by activation of trichloroacetimidate by H2SO4-silica only. All glycosylation reactions resulted in the formation of the desired linkage with absolute stereoselectivity and yielded the required derivatives in good to excellent yields. Both azido and phthalimido groups have been used as the precursor of the desired acetamido group depending on the requirement of 1,2-cis- or 1,2-trans-glycosidic linkage.
authors.affiliation: Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, West Bengal, India.
authors.forename: Rituparna
authors.initials: R
authors.lastname: Das
authors.affiliation: Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, West Bengal, India.
authors.forename: Mukul
authors.initials: M
authors.lastname: Mahanti
authors.affiliation: Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, West Bengal, India. Electronic address: sugarnet73@hotmail.com.
authors.forename: Balaram
authors.initials: B
authors.lastname: Mukhopadhyay
mesh_terms: D002240:Carbohydrate Sequence; D020609:Edwardsiella tarda / Q000737:chemistry*; D008969:Molecular Sequence Data; D015394:Molecular Structure; D019081:O Antigens / Q000737:chemistry* / Q000302:isolation & purification; D009844:Oligosaccharides / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D019081:O Antigens; D009844:Oligosaccharides
keywords: Acetamido sugars; Bacterial O-antigen; H(2)SO(4)–silica