Bausteine von Oligosacchariden, XCVIII. Synthese von Oligosacchariden der inneren Core‐ und Lipoid‐A‐Region von Lipopolysacchariden

Building Units of Oligosaccharides, XCVIII. – Synthesis of Oligosaccharides of the Inner Core and Lipoid A Region of Lipopolysaccharides Glycosidic coupling of the Hep‐Kdo disaccharide bromide 9 with the Lipoid A analogous disaccharide 10 gives the tetrasaccharide 11 which was deprotected to yield the tetrasaccharide L‐α‐D‐Hepp‐(1→5)‐α‐Kdop‐(2→6)‐β‐D‐GlcpNhm‐(1→6)‐D‐GlcNhm (18). In a further block synthesis 10 was glycosylated with the Hep‐[Kdo]‐Kdo donor 24. Deprotection of the corresponding pentasaccharide 25 furnished L‐α‐D‐Hepp‐(1→5)‐[α‐Kdop]‐(2→4)‐α‐Kdop‐(2→6)‐β‐D‐GlcpNhm‐(1→6)‐D‐GlcNhm (31). Sheep erythrocytes can be coated with these oligosaccharides 18 and 31. The resulting complexes are used as synthetic antigens and immunogens containing the disaccharide L‐α‐D‐Hepp‐(1→5)‐α‐Kdop and the branched trisaccharide L‐α‐D‐Hepp‐[α‐Kdop‐(2→4)]‐α‐Kdo as antigenic determinants.