Derivatives of 5,7-diamino-3,5,7,9-tetradeoxynon-2-ulosonic acids are essential constituents of some bacterial polysaccharides and glycoproteins. In order to establish reliably the configuration of the natural sugars, nine stereoisomeric 5,7-diacetamido-3,5,7,9-tetradeoxynon-2-ulosonic acids were synthesized, including di-N-acetyl-legionaminic and -pseudaminic acids (the D-glycero-D-galacto and L-glycero-L-manno isomers, respectively) and their isomers at C-4, C-5, C-7, and C-8 having the L-glycero-D-galacto, D-glycero-D-talo, L-glycero-D-talo, D-glycero-L-altro, L-glycero-L-altro, D-glycero-L-manno, and L-glycero-L-gluco configurations. Synthesis was performed by condensation of 2,4-diacetamido-2,4,6-trideoxy-L-gulose, -D-mannose, -D-talose, and -L-allose with oxalacetic acid under basic conditions, the reaction of the last two precursors being accompanied by epimerisation at C-2. The 1H and 13C NMR data of the synthetic compounds are discussed. Acetylated methyl esters of the C-7 and C-8 isomeric nonulosonic acids were prepared and used for analysis of the side-chain conformation by NMR spectroscopy.
NMR, synthesis, LPS, Bacterial, acid, NMR spectroscopy, pseudaminic acid, putative, identification, spectroscopy, 5, 7-diamino-3, 7, 9-tetradeoxynon-2-ulosonic acid, lipopolysaccharide components, 7-diacetamido-3, 9-tetradeoxynon-2-ulosonic acids, 2, 4-diacetamido-2, 4, 6-trideoxyhexoses, legionaminic acid, 9-teradeoxynonulosonic acid, component, isomer
NCBI PubMed ID: 11595217Publication DOI: 10.1016/S0008-6215(01)00235-XJournal NLM ID: 0043535Publisher: Elsevier
Correspondence: tsvetkov@ioc.ac.ru
Institutions: N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Prospeckt 47, Moscow, Russian Federation, Forschungszentrum Borstel, Zentrum fur Medizin und Biowissenschaften, Borstel, Germany.
Methods: 13C NMR, 1H NMR
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