Synthesis and identification in bacterial lipopolysaccharides of 5,7-diacetamido-3,5,7,9-tetradeoxy-d-glycero-d-galacto- and -d-glycero-d-talo-non-2-ulosonic acids Original Research Article

5,7-Diacetamido-3,5,7,9-tetradeoxy-d-glycero-d-galacto- and -d-glycero-d-talo-non-2-ulosonic acids were synthesized by condensation of 2,4-diacetamido-2,4,6-trideoxy-d-mannose with oxalacetic acid. Comparison of the 1H and 13C NMR data and the specific optical rotation values of these monosaccharides and the corresponding l-glycero-d-galacto and l-glycero-d-talo isomers synthesized earlier [Tsvetkov, Y. E.; Shashkov, A. S.; Knirel, Y. A.; Backinowsky, L. V.; Zähringer, U. Mendeleev Commun. 2000, 90–92] with data of the natural compounds enabled the identification in bacterial lipopolysaccharides of derivatives of 5,7-diamino-3,5,7,9-tetradeoxy-d-glycero-d-galacto-non-2-ulosonic (legionaminic) acid and epimers of legionaminic acid at C-4 and C-8.