Petra Ossowski

Studies of Hexuronic Acid Ester Glycals and the Synthesis of 2-Deoxy-β-glycoside Precursors

Abstract The hexuronic acid methyl ester glycals with L-ribo (7), D-lyxo (9), and D-xylo configuration (11a) were synthesized and their conformations and that of the D-arabino derivative 2a were studied. Using the N-iodosuccinimide alycosylation procedure these glycals were transformed into cyclohexyl 2-deoxy-2-iodoglycosides 13 - 28 and their α/β-anomer ratios determined by 1H NMR spectrocopy. The mechanism of the N-iodosuccinimide glycosylation and the correlation between glycal conformation and glycoside configuration are discussed.

Silver Zeolite as Promoter in Glycoside Synthesis. The Synthesis of 2-Deoxy-β-D-Glycopyranosides

Abstract The use of silver zeolite as a promoter for the preparation of β-linked 2-deoxygtycosides and disaccharides of biological relevance has been explored. Starting from benzoylated glycosyl bromides, the total yield of glycosides varies from 54 to 84% and the α:β ratio from 0.25 to 1.18.

Syntheses of trisaccharides related to Salmonella serogroup E O-antigenic polysaccharides

Abstract Syntheses of p -trifluoroacetamidophenyl O -β- d -mannopyranosyl-(1→4)- O -α- l -rhamnopyranosyl-(1→3)-α- d -galactopyranoside ( 3 ) and p -trifluoroacetamidophenyl O -β- d -galactopyranosyl-(1→6)- O -β- d -mannopyranosyl-(1→4)-α- l -rhamnopyranoside ( 11 ) are described. Silver zeolite was used as promoter for constructing the β- d -mannosyl linkages from 6- O -acetyl-2,3,4-tri- O -benzyl-α- d -mannopyranosyl bromide and the appropriate monohydroxy compound.