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:     

Synthesis of novel furoquinolines and furobenzodiazepines from tetronic acid

Condensation of tetronic acid with 2-cyano-, 2-ethoxycarbonyl-, 2-carboxy-, and 2-aminoanilines gave novel furoquinolines and furobenzodiazepines. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2220–2226, November, 2007.     

Alkaloids from Arundo donax. XVII. Structure of the Dimeric Indole Alkaloid Arundaphine

The newdimeric alkaloid arundaphine, a tryptamine-tryptamine base, was isolated from roots and rhizomes of Arundo donax (Poaceae). Spectral data and an x-ray structure analysis established its structure as 1-[3-(2-dimethylaminoethyl)-5-hydroxy-1H-4-indolyl]-3-hydroxy-3-(2-methylaminoethyl)-2-indolinone.     

A sulfated glycoside from the preparation “tribestan”

The chemical composition and structures of the steroid glycosides forming the active principle of the preparation “tribestan,” which is used for treating impotence and female infertility, have been studied. It has been shown that together with trillin, prosapogenin A of dioscin, trillarin, dioscin, gracillin, protodioscin, and protogracillin, tribestan contains a diosgenin rhamnoglucoside sulfated in position 4 of the glucose residue, the structure of which has been shown by chemical and physicochemical methods. Institute of Ecological Genetics, Academy of Sciences of the Moldavian SSR, Kishinev. Center for Biogenic Stimulators, Sofia, Bulgaria. N. D. Zelinskii Institute of Organic Chemistry, Academy of Sciences of the USSR, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 649–652, September–October, 1990.     

Carbohydrates ofAllium. II. A new type of glucofructan fromAllium sativum

By fractionating the total glucofructan from the bulbs ofAllium sativum L. a homogeneous glucofructan with a molecular weight of 2300 has been isolated. On the basis of its characteristics, a comparison of IR and¹³C NMR spectra, and the results of periodate and chromium trioxide oxidation and of methylation, it has been established that this glucofructan is a new type of compound of this class, containing both inulin (2 → 1) and levan (2 → 6) glycosidic bonds.     

Polysaccharides of algae 67. Carrageenan from Pacific red alga Turnerella mertensiana (Gigartinales,Rhodophyta)

A sulfated galactan composed of nearly equimolar amounts of d-galactose, 3,6-anhydro-d-galactose, and sulfate was isolated from the red alga Turnerella mertensiana collected in the Sea of Japan. The structures of native polysaccharide and its alkaline modification products were studied by NMR spectroscopy. The polysaccharide molecules were shown to contain a linear carbohydrate chain consisting of alternating 3-linked β-d-galactopyranose 4-sulfate and 4-linked 3,6-anhydro-α-d-galactopyranose residues (known as к-carrageenan), which is typical of carrageenans, but the regularity of polymer structure is masked by the presence of some 3,6-anhydro-α-d-galactose 2-sulfate (ι-carrageenan units) and α-D-galactose 6-sulfate (µ-carrageenan units) instead of 3,6-anhydro-α-d-galactose. Upon addition of potassium chloride (up to 4%) to a solution of the native polysaccharide, about half of the substance transforms into gel. The gel-forming fraction is к-ι-µ-hybrid carrageenan with the ～65 : 15 : 20 ratio of к-, ι-, and µ-units. The non-gelling fraction contains the к-, ι-, and µ-units at the ratio of ～46 : 12 : 42. The gel-forming carrageenan product free of µ-units can be otained in ～30% yield (based on the dry biomass) by alkaline treatment of the alga prior to extraction of the polysaccharide.

     

Structure, 1H and 13C NMR spectra, and biological activity of the antibiotic INA-1278 related to irumamycin and produced by the experimental Streptomyces sp. strain No. 1278

The screening for novel antibiotic producers by selection methods revealed the Streptomyces sp. strain No. 1278 producing the antibiotic INA-1278, which exhibits antimicrobial and antifungal activities. This compound was isolated from the liquid culture by extraction with organic solvents and purified by chromatographic methods. The structure of this antibiotic was studied by mass spectrometry and ¹H and ¹³C NMR spectroscopy. An analysis of the results of the investigation indicate that the compound INA-1278 is structurally related to the antibiotic irumamycin, which has been studied earlier. However, the novel antibiotic may differ from irumamycin in the configurations of some asymmetric centers, which were not established at the present stage of our research.     

Diastereoselective synthesis of polyfunctional compounds based on the tandem sequence of threeAdE reactions using cyclic vinyl ethers as first alkene components

The reaction of the bicyclic thiophanium ions salts, generated by the sequential interaction ofp-TolSCI with dihydropyran or 1-methoxycycloalkene and then with an acyclic alkyl vinyl ether in the presence of a Lewis acid and with silicon- or tin-capped π-donors, proceeds with high diastereoselectivity at all newly created chiral centers. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 82–94, January, 2000.