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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Archives of microbiology 163 (1995), S. 138-142 
    ISSN: 1432-072X
    Keywords: Staphylococcus aureus ; Osmoregulation ; Proline betaine ; Nuclear magnetic resonance spectroscopy ; Coagulase-negative staphylococci
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Proline betaine is an osmoprotectant that is at least as effective as glycine betaine, and more effective than L-proline, for various strains of Staphylococcus aureus, and Staphylococcus epidermidis and Staphylococcus saprophyticus. 13C NMR studies revealed that proline betaine accumulated to high levels in osmotically stressed S. aureus, but was also detected in organisms grown in its presence in the absence of osmotic stress. Competition experiments indicated that proline betaine was taken up by the proline transport systems of S. aureus, but not by the high affinity glycine betaine transport system.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Chemistry - A European Journal 2 (1996), S. 1197-1200 
    ISSN: 0947-6539
    Keywords: aromaticity ; MacDonald condensation ; porphyrinoids ; pyrroledialdehydes ; tripyrranes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Acid-catalyzed condensation of tripyrranes with pyrrole-2,5-dicarboxaldehydes, followed by oxidation with an electron-deficient quinone, affords porphyrin products in excellent yields. This previously little used methodology has now been exploited in the synthesis of novel porphyrin structures, including tetrapyrrolic compounds with fused aromatic rings. By utilizing other aromatic or unsaturated dialdehydes, the “3+1” approach also allows the synthesis of new aromatic porphyrinoid systems, including benzene- and pyridine-containing macrocycles and carbaporphyrins.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 0947-6539
    Keywords: aromaticity ; porphyrins ; pyridones ; MacDonald condensation ; tautomerizations ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of the first example of an aromatic pyridine-containing porphyrinoid 10 has been accomplished in excellent yields by the acid-catalyzed “3 + 1” condensation of 3-hydroxy-pyridinedicarboxaldehyde (8) with tri-pyrrane 9. The key intermediate 8 was obtained by the selenium dioxide oxidation of the known biscarbinol 7. The aromaticity of “oxypyriporphyrin” 10 has been confirmed by MS, NMR, IR, and UV/Vis spectroscopy. This system afforded a monocation in 0.2% TFA-chloroform, and a dication was observed in 2% TFA-chloroform; these species also retained macrocyclic aromaticity. Oxypyriporphyrin readily formed the corresponding metal chelates 14a-c by reaction with zinc, copper(II), or nickel(II) acetate, and this observation suggests that there are extensive possibilities for the use of 10 in coordination chemistry. Oxypyriporphyrin and the related semiquinone system oxybenziporphyrin represent the first two members of a new class of aromatic porphyrinoids.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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