SYNTHESIS AND NMR SPECTROSCOPIC INVESTIGATION OF OLIGOSACCHARIDES CONTAINING KDO AND L-GLYCERO-D-MANNO-HEPTOPYRANOSYL RESIDUES

The disaccharides O-(sodium 3-deoxy-alpha-D-manno-2-octulopyranosylona te)-(2 --> 8)-sodium (allyl 3-deoxy-beta-D-manno-2-octulopyranosid)ona te (8), O-L-glycero-alpha-D-Manno-heptopyranosyl-(l --> 7)-sodium (all yl 3-deoxy-beta-D-manno-2-octulopyranosid)onate (12), and 0-alpha-D-ma nnopyranosyl-(1 --> 7)-sodium (allyl 3-deoxy-beta-D-manno-2-octulopyra nosid)onate (21) and the branched trisaccharides O-L-glycero-alpha-D-m anno-heptopyranosyl-(l --> 7)-[O-(sodium 3-deoXy-alpha- and -beta-D-ma nno-2-octulopyranosylonate)-(2 --> 8)]-sodium (allyl 3-deoXY-beta-D-ma nno-2-octulopyranosid)onate (15 and 16) and 0-alpha-D-mannopyranosyl-( 1 --> 7)-[O-(sodium 3-deoxy-alpha-D-manno-2-octulopyranosylonate)-(2 - -> 8)]-sodium (allyl 3-deoxy-beta-D-manno-2-octulopyranosid)onate (24) were prepared. Per-O-acetylated mannopyranosyl or Kdo bromide derivat ives were employed for the glycosylation steps under Helferich conditi ons, whereas the imidate derivative 9 was used for the coupling of the L-glycero-D-manno-heptopyranosyl residues. The oligosaccharides were fully characterized by NMR spectroscopic data. Their structures corres pond to an artificial linkage pattern providing a potential cross-reac tive epitope for antibodies directed against the inner-core-region of enterobacterial as well as chlamydial lipopolysaccharides.