ORGN 411 |
| There are two parts of this poster. One is the synthesis of an N-trichloroacetyl derivative of neuraminic acid with phenyltrifluoroacetimidate as the anomeric leaving group. This new glycosyl donor reacted with p-tolyl-1-thio-4,6-O-benzylidene-β-D-galactopyranoside, and exhibited exclusive α selectivity in 60% yield. The influences of solvent, additives and concentration of promoter (TMSOTf) on sialyation were investigated. The other part is the total syntheses of two octasaccharides tumor associated antigens N3 major and N3 minor by using the iterative one-pot strategy. The building blocks triaccharide Lea and trisaccharide Lex were constructed using p-tolyl-1-thio-galactoside as the donor and partially protected p-tolyl-1-thio-glucoside as the acceptors via stereoselective condensation reactions. The strategy proved that complex molecules can be rapidly assembled using near stoichiometric amount of building blocks. |
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New Reactions and Methodology, Total Synthesis, Materials, Devices and Switches, Lipids, Nucleotides and Mimetics
8:00 PM-10:00 PM, Tuesday, March 27, 2007 Hyatt Regency Chicago -- Riverside Center, Poster
Division of Organic Chemistry |