Synthesis 2007(9): 1412-1420  
DOI: 10.1055/s-2007-965995
PAPER
© Georg Thieme Verlag Stuttgart · New York

Synthesis of the Rhamnosyl Trisaccharide Repeating Unit To Mimic the Antigen Determinant of Pseudomonas syringae Lipopolysaccharide

Chung-Shan Yu*, Heng-Yen Wang, Li-Wu Chiang, Kai Pei
Department of Biomedical Engineering and Environmental Sciences, National Tsing-Hua University, Hsinchu, No. 101 sec. 2, Guang-Fu Rd., 300 Taiwan, Taiwan
Fax: +886(3)5718649; e-Mail: csyu@mx.nthu.edu.tw;
Further Information

Publication History

Received 15 January 2007
Publication Date:
23 March 2007 (online)

Abstract

The trisaccharide 2,3,4-O-tribenzyl-α-l-rhamnosyl-(1→3)-4-O-acetyl-2-O-benzoyl-(1→2)-4-O-acetyl-3-O-benzoyl-α-l-rhamnosyl-1-(4-tolyl)thio-α-l-rhamnopyranoside was prepared from the thio-sugar 1-(4-tolyl)thio-α,β-l-rhamnopyranoside from the nonreducing end to the reducing end. The two acceptors possessing 2- and 3-OH groups for the construction of the trisaccharide were obtained from a 2,3-benzylidine-protected thio-sugar in a one-pot deprotection manner in a respective ratio of 1:2.5. As donors for glycosylation, the thio-sugars of both mono- and disaccharides were converted to trichloroacetimido rhamnosides. Through this chemoselective strategy, a trisaccharide was obtained that retained an anomeric thio group for coupling with ceramide moieties. Bioassays are in progress.

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Yu, C.-S.; Yeh, C.-H.; Chiang, L.-W. manuscript submitted.