Synthesis of Oligosaccharides from the Inner Core Structure of Haemophilus Influenzae and Neisseria meningitidis Lipopolysaccharides

Abstract: This thesis describes the synthesis of oligosaccharides corresponding to different parts of the lipopolysaccharide (LPS) inner core structure from Haemophilus influenzae and Neisseria meningitidis. Chapter 2 describes the synthesis of a protected trisaccharide common to H. influenzae and N. meningitidis LPS, which can be used as a versatile precursor in further syntheses of larger LPS structures. In Chapter 3 syntheses towards phosphoethanolamine substituted trisaccharides corresponding to H. influenzae and N. meningitidis structures are presented. In Chapter 4 the synthesis of a H. influenzae tetrasaccharide structure, with and without a phosphoethanolamine substituent in the 6-position of the second heptose unit, is described. Conjugation to biotin of these two tetrasaccharides is also performed. Chapter 5 describes the synthesis of a spacer-equipped Kdo acceptor that is subsequently attached to the tetrasaccharide described in Chapter 4 forming a pentasaccharide from the inner core structure of H. influenzae. Similar to the synthesis of the tetrasaccharide, a phosphoethanolamine is attached to the 6 position of the second heptose. Chapter 5 also describes the synthesis of various Kdo thioglycoside donors and their evaluation in glycosylation reactions using different promoters and reaction conditions.