Phthalic Anhydride-Mediated Direct Glycosylation of Anomeric Hydroxy Arabinofuranose: Synthesis of Repeating Oligoarabinofuranoside and Tetradecasaccharide Arabinan Motif of Mycobacterial Cell Wall

Abstract

An efficient direct phthalic anhydride-mediated one-pot glycosylation method employing anomeric hydroxy arabinofuranose as glycosyl donor and triflic anhydride as activating agent has been developed. This method afforded the desired di- and oligoarabinofuranosides in good yields even in gram scale glycosylation when t-butylphthalic anhydride was used. Moreover, our new method can be further extended to the syntheses of repeating oligoarabinofuranoside and tetradecasaccharide arabinan motif found in mycobacterial cell wall.

Synthesis and Immunological Comparison of Differently Linked Lipoarabinomannan Oligosaccharide–Monophosphoryl Lipid A Conjugates as Antituberculosis Vaccines

“…The upstream terminal oligosaccharides of LAM consist of linear and branched β-(1→2)-, α-(1→3), and α-(1→5)-linked arabinofuranosides capped usually by an α-(1→2)-linked dimannopyranose. ,, Due to the intriguing structure and biological activity of LAM, , great effort and progress have been made in the synthesis of LAM oligosaccharides, − especially by the Lowary, Seeberger, and Prandi groups, and in the application of synthetic oligosaccharides to vaccine development. − Recently, our group prepared several LAM oligosaccharide–keyhole limpet hemocyanin (KLH) conjugates and tested their immunological activities . Although these conjugates were demonstrated to possess promising immunogenicity, e.g., to elicit LAM oligosaccharide-specific antibody responses, their activities were relatively low.…”