Georgy V. Zatonsky

Structure of the O-specific polysaccharide of Citrobacter freundii O3a,3b,1c

The following structure of the O-specific polysaccharide of Citrobacter braakii O7a,3b,1c was established using sugar and methylation analyses and NMR spectroscopy, including 2D COSY, TOCSY, NOESY, and 1H, 13C heteronuclear single-quantum coherence (HSQC) experiments: (struture: see text). The main D-mannan chain of the polysaccharide studied has the same structure as the O-specific polysaccharide of Escherichia coli O9, Klebsiella pneumoniae O3, and Hafnia alvei PCM 1223.

D- and L-Aspartic Acids: New Non-sugar Components of Bacterial Polysaccharides

For the first time in bacterial polysaccharides, residues of D- and L-aspartic acids were identified as N-acyl substituents of 4-amino-4,6-dideoxy-D-glucose in the O-antigens of enterobacteria of the generaProvidencia andProteus.

Structure of the O-Specific Polysaccharide of Hafnia Alvei 23 Having an Oligosaccharide-Phosphate Repeating Unit

ABSTRACT Lipopolysaccharide (LPS) of Hafnia alvei 23 has an acid-labile O-specific polysaccharide (OPS) with a pentasaccharide-phosphate repeating unit containing D-Glc1P, D-GlcNAc, L-Fuc, 6-deoxy-D-talose (D-6dTal), 4-acetamido-4,6-dideoxy-D-glucose (D-Qui4NAc), and an O-acetyl group. A partially degraded OPS was obtained by hydrolysis of LPS with 0.25 M sodium acetate in aqueous 0.5% acetic acid. Fractionation of LPS on Sephadex G-200 in DOC buffer allowed isolation of long-chain LPS species which, together with OPS, were studied by methylation analysis, chemical degradations (O-deacetylation, dephosphorylation with 48% hydrofluoric acid, Smith degradation), and 1H and 13C NMR spectroscopy, including 2D COSY, TOCSY, NOESY, and H-detected 1H,13C heteronuclear single-quantum coherence (HSQC) experiments. The following structure of the repeating unit of OPS was established:

Reactions of p-toluenesulfenyl chloride with enol acetates. The synthetic potential of the resulting adducts

Reactions of vinyl and propen-2-yl acetates with p-toluenesulfenyl chloride afforded the corresponding α-chloro-β-(p-tolyl)thioalkyl acetates in nearly quantitative yields.These adducts reacted with some C-nucleophiles in the presence of Lewis acids to give the corresponding alkylation products.

Synthesis and luminescence-spectral properties of benzoheterocyclic β-diketones and their complexes with europium

In order to solve some environmental and biomedical problems, we synthesized fluorinated heterocyclic β-diketones and estimated the luminescence-spectral properties of these compounds complexes with the ions of rare-earth elements as the possible reagents for immunofluorescence analysis.

Structure of the O-polysaccharide of Pseudomonas syringae pv. delphinii NCPPB 1879T Having Side Chains of 3-Acetamido-3,6-dideoxy-D-galactose Residues

AbstractThe O-polysaccharide (OPS) was obtained from the lipopolysaccharide of Pseudomonas syringae pv. delphinii NCPPB 1879T and studied by sugar and methylation analyses, Smith degradation, and 1H- and 13C-NMR spectroscopy. The OPS was found to contain residues of L-rhamnose (L-Rha) and 3-acetamido-3,6-dideoxy-D-galactose (D-Fuc3NAc), and the following structure of the major (n = 2) and minor (n = 3) heptasaccharide repeating units of the OPS was established:

Solvolysis of allylic prostaglandin mesylates : moderate 1,3-syn-stereoselectivity

\begin{gathered} {\alpha} - {D} - {Fuc}p3{NAc} - (1 \to 2) - {\alpha} - {D} - {Fuc}p3{NAc} - (1 \to 2) - {\alpha} - {D} - {Fuc}p3{Nac} \hfill \\ { 1} \hfill \\ { } \downarrow \hfill \\ { 4} \hfill \\ { } \to {2} - {\alpha} - {L} - {Rha}p - (1 \to 3) - {\alpha} - {L} - {Rha}p - (1 \to 3) - {\alpha} - {L} - {Rha}p(1 \to n) - {\alpha} - {L} - {Rha}p - (1 \to \hfill \\ \hfill \\ \end{gathered}

Fluorinated tetraketone derivatives of N-substituted carbazoles and their Eu(III) complexes for fluorescence immunoassay

The OPS is distinguished by the presence of oligosaccharide side chains consisting of three D-Fuc3NAc residues that are connected to each other by the (α1→2)-linkage. The OPS is characterized by a structural heterogeneity due to a different position of substitution of one of the four L-rhamnose residues in the main chain of the repeating unit as well as to the presence of oligosaccharide units with an incomplete side chain.