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[Synthesis of trisaccharide units from capsular polysaccharides of Streptococcus pneumoniae]
H Paulsen1, B Helpap, J P Lorentzen
1Institut für Organische Chemie, Universität Hamburg, 13 Bundesrepublik Deutschland.
Abstract:
In the presence of silver silicate as promoter, the reaction of glycosyl bromide of 2-azido-2-deoxy-D-mannose with 1,6-anhydro-2,3-di-O-benzyl-beta-D- glucopyranose led to derivatives of the disaccharide beta-D-ManpNac-(1----4)-D- Glcp. The derivatives were activated into disaccharide halides and employed as glycosyl donors in block synthesis. By chain extension with L-rhamnose and D-glucose, four trisaccharides were synthesized. They represent components of capsular polysaccharide "repeating units" of various Streptococcus pneumoniae types, beta-D-Man-pNAc-(1----4)-alpha-D-Glcp-(1----2)-L-Rhap (type 19 F), beta-D-ManpNAc-(1----4)-alpha-D-Glcp-(1----3)-L-Rhap (type 19 A), beta-D-ManpNAc-(1----4)-alpha-D-Glcp-(1----4)-D-Glcp (type 9 A), and beta-D-ManpNAc-(1----4)-beta-D-Glcp-(1----4)-D-Glcp (type 9 V).