Synthesis and serological characterization of l- glycero-α- d- manno-heptopyranose-containing di- and tri-saccharides of the non-reducing terminus of the Escherichia coli K-12 LPS core oligosaccharide

Synthesis of the title trisaccharide was accomplished by sugar chain extension starting from the non-reducing terminus: coupling of Glc pNAc with ld-Hep p, then adding Glc p-OAll. An alternative route started from the reducing end: coupling of ld-Hep p with Glc p-OAll, then addition of Glc pNAc. In the synthesis of the title disaccharide a modification of the first approach was employed. The allyl glycosides were coupled with cysteamine, activated with thiophosgene and conjugated to bovine serum albumin (BSA). The neoglycoconjugates obtained were used in immunochemical studies of monoclonal and polyclonal antibodies directed against Escherichia coli K-12 lipopolysaccharide.