Design and applications of active and latent thioglycosyl donors toward the synthesis of the disaccharide repeating unit of Haemophilus pleuropneumoniae serotype 4 CPS.

Abstract

Chapter 1 describes, in a schematic manner, various approaches to the synthesis of the repeating disaccharide unit of H. pleuropneumoniae serotype 4 capsular polysaccharide. Chapter 2 describes an indirect use of thioglycosides, by conversion into glycosyl halides, and their direct use with promoters such as dimethyl (methylthio) sulfonium triflate (DMTST) and N-bromosuccinimide (NBS). Chapter 3 describes the development of the concept of active and latent thioglycosyl donors which combines the features of armed and disarmed glycosyl donors is presented. Reactivation of latent donor para-nitrophenyl thioglycoside is also proposed. In Chapter 4, we describe the synthesis of a complex series of thioglycosides under PTC conditions. During this approach we discovered that the use of the lipophilic PTC catalyst tretrabutylammonium hydrogen sulfate (TBAHS) (1 eq.) and ethyl acetate as solvent greatly improve the reaction rates. Chapter 5 presents our approaches to the stereospecific syntheses of 1,2-trans-aryl-1-thio-$\beta$-D-glycobiosides, active and latent tioglycosyl donors, as well as 1,2-trans-$\beta$-D-glycosyl phosphates by PTC. Chapter 6 describes our approaches to the synthesis of the repeating disaccharide unit of H. pleuropneumoniae serotype 4 (CPS) via thioglycosyl donors using different thiophilic promoters such as NBS, DMTST and N-iodosuccinimide (NIS)/trifluoromethanesulfonic acid (TfOH). (Abstract shortened by UMI.)