Synthesis of a neoglycoconjugate containing a Chlamydophila psittaci-specific branched Kdo trisaccharide epitope

The branched Kdo trisaccharide sodium (3-deoxy-α-d-manno-oct-2-ulopyranosyl)onate-(2→8)-[sodium (3-deoxy-α-d-manno-oct-2-ulopyranosyl)onate-(2→4)]-sodium (allyl 3-deoxy-α-d-manno-oct-2-ulopyranosid)onate has been prepared utilizing the regioselective glycosylation of the C-7, C-8 diol entity of a Kdo monosaccharide acceptor with a Kdo bromide donor followed by the attachment of the third Kdo unit to O-4 of the disaccharide intermediate. Deacetylation and hydrolysis of the methyl ester groups furnished the trisaccharide allyl glycoside which was converted into the corresponding 3-(2-aminoethylthio)propyl glycoside. Subsequent covalent attachment to bovine serum albumin furnished a neoglycoconjugate serving as an antigen for the induction of Chlamydophila psittaci-specific monoclonal antibodies.