Synthesis of some oligosaccharide fragments of biological and chemical interest using thioglycosides

Abstract: This thesis describes the synthesis of oligosaccharide derivatives corresponding to the repeating unit of the O-antigen from two different bacteria, Shigella dysenteriae type 1 and Salmonella thompson serogroup Ci, and fragments thereof. Synthesis of a decasaccharide of chemical interest for studying carbohydrate dynamics in elongated molecules is also described. All syntheses are based upon thioglycoside intermediates as building blocks. Furthermore, application of the anomeric one bond scalar coupling constant (ljC-l,H-l) as a tool for detecting 1,2-orthoester formation in oligosaccharide synthesis is also emphasized.