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  • 1
    Electronic Resource
    Electronic Resource
    Stoffwechselprodukte von Mikroorganismen 183. Mitteilung. Imacidin, ein neues Acylpeptidantibioticum aus Streptomyces olivaceus (1979)
    Springer
    Archives of microbiology 122 (1979), S. 219-229 
    Details
    ISSN: 1432-072X
    Keywords: Cyclodepsipeptide antibiotics from actinomycetes ; Cell wall synthesis inhibitor ; Streptomyces olivaceus ; Imacidin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Ein Stamm von Streptomyces olivaceus, Tü 1379, bildet neben den bekannten Bakterienfarbstoffen Prodigiosin C-25 und Metacycloprodigiosin mehrere vermutlich cyclische β-Hydroxyacyldecapeptide, hauptsächlich Imacidin B und C, die sich in der Kettenlänge des Acylrestes unterscheiden. Diese Antibiotica werden durch schwache Alkalien schnell verändert, wobei Hydroxyacylpeptide mit unveränderter Aminosäure-Zusammensetzung, aber verringerter biologischer Wirksamkeit, Imacidinsäuren, entstehen, die auch im nativen Rohprodukt enthalten sind. Die Imacidine besitzen ein enges Wirkungsspektrum und hemmen die Zellwandsynthese.
    Notes: Abstract Streptomyces olivaceus, strain Tü 1379 produces beside the red dyestuff prodigiosin several closely related hitherto unknown cyclodepsipeptide antibiotics, mainly imacidine B and C and imacidinic acids. The antibiotics affect murein biosynthesis. Only actinomycetes are inhibited.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00411284
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  • 2
    Electronic Resource
    Electronic Resource
    Metabolic products of microorganisms. 192. The anthraquinones of the Aspergillus glaucus group. II. Biological activity (1980)
    Springer
    Archives of microbiology 126 (1980), S. 231-236 
    Details
    ISSN: 1432-072X
    Keywords: Antibiotics ; Polyhydroxvanthraquinones ; Catenarin ; Emodin ; Erythrogtaucin ; Physcion ; Rubrocristin ; Viocristin ; Aspergillus cristatus ; Bacillus brevis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract From the mycelia of Aspergillus cristatus the following anthraquionic pigments were isolated: catenarin, emodin, erythroglaucin, rubrocristin, physcion, physcion-9-anthrone, questin, viocristin, and isoviocristin. The latter two do not belong to the 9, 10-anthraquinone series but to the 1,4-anthraquinones, and so far they have not been reported among naturally occurring quinones. Emodin, catenarin, viocristin, and isoviocristin snowed antibacterial activity with minimal inhibitory concentrations ranging from 1–10 μg/ml. In Bacillus brevis catenarin and emodin inhibited the incorporation of uracil and leucine preferentially. At higher concentrations the incorporation of thymidine into the trichloroacetic acid-precipitable fraction of cells was also affected. In the presence of viocristin or isoviocristin all three macromolecular syntheses came to a halt. Rubrocristin, erythroglaucin, and physcion showed no significant inhibitory effects. In Ehrlich ascites carcinoma cells catenarin, emodin, and viocristin inhibited the incorporation of uridine and thymidine. The incorporation of leucine was hardly affected. In vitro, inhibition of DNA-dependent RNA polymerase from Escherichia coli by catenarin and to a lesser extent by emodin was observed, whereas rubrocristin (catenarin-8-methyl ether), physcion, and erythroglaucin were not active.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00409925
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  • 3
    Electronic Resource
    Electronic Resource
    Metabolic products of microorganisms. 185. The anthraquinones of the Aspergillus glaucus group. I. Occurrence, isolation, identification and antimicrobial activity (1980)
    Springer
    Archives of microbiology 126 (1980), S. 223-230 
    Details
    ISSN: 1432-072X
    Keywords: Antibiotics from Aspergilli ; Emodin ; Erythroglaucin ; Physcion ; Physcion-9-anthrone ; Questin ; Catenarin ; Rubrocristin ; Anthraquinones
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The occurrence of emodin, erythroglaucin, physcion, physcion-9-anthrone, questin, catenarin, and catenarin-8-methyl ether in different species of the Aspergillus glaucus group (genus Eurotium) was investigated. So far catenarin-8-methyl ether (1, 4, 6-trihydroxy-8-methoxy-3-methylanthraquinone) has not been described as a natural product; it was therefore given the name rubrocristin. The chemical and physical properties of rubrocristin are reported. In addition a new violet pigment (C16H12O5) was isolated and characterized by its MS-, IR- and UV-spectra. The antimicrobial properties of all substances were examined in the agar diffusion assay. Gram-positive bacteria were the most sensitive organisms and catenarin was the most active naturally occurring substance. Synthetically obtained 1, 4, 6, 8-tetrahydroxy-anthraquinone was slightly more active than catenarin, whereas rubrocristin showed no antibacterial activity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00409924
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  • 4
    Electronic Resource
    Electronic Resource
    Biosynthesis of the marine antibiotic pentabromopseudilin. Part 1. The benzene ring (1994)
    s.l. : American Chemical Society
    The @journal of organic chemistry 59 (1994), S. 3604-3608 
    Details
    ISSN: 1520-6904
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/jo00092a020
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  • 5
    Electronic Resource
    Electronic Resource
    Reactions of the melatonin metabolite AMK (N1-acetyl-5-methoxykynuramine) with reactive nitrogen species: Formation of novel compounds, 3-acetamidomethyl-6-methoxycinnolinone and 3-nitro-AMK (2005)
    Oxford, UK : Munksgaard International Publishers
    Journal of pineal research 39 (2005), S. 0 
    Details
    ISSN: 1600-079X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract:  The melatonin metabolite N1-acetyl-5-methoxykynuramine (AMK) was found to be unstable in air when adsorbed on a thin-layer silica gel chromatography plate, a result that is in good agreement with the relatively high reactivity of this compound. Three novel main products were separated from the reaction mixture and identified by mass spectrometry and nuclear magnetic resonance data as: (i) 3-acetamidomethyl-6-methoxycinnolinone (AMMC), (ii) 3-nitro-AMK (AMNK, N1-acetyl-5-methoxy-3-nitrokynuramine), and (iii) N-[2-(6-methoxyquinazolin-4-yl)-ethyl]-acetamide (MQA). AMMC and AMNK are shown to be nonenzymatically formed also in solution, by nitric oxide (NO) in the first case, and by a mixture of peroxynitrite and hydrogen carbonate, in the second one. The use of three different NO donors, PAPA-NONOate, S-nitroso-N-acetylpenicillamine and sodium nitroprussiate led to essentially the same results, with regard to a highly preferential formation of AMMC; AMNK was not detected in these reaction systems. Competition experiments with the NO scavenger N-acetylcysteine indicate a somewhat lower reactivity compared with the competitor. Peroxynitrite led to AMNK formation in the presence of physiological concentrations of hydrogen carbonate at pH 7.4, but not in its absence, indicating that nitration involves a mixture of carbonate radicals and NO2, formed from the peroxynitrite-CO2 adduct. No AMMC was detected after AMK exposure to peroxynitrite. Both AMNK and AMMC exhibited a much lower reactivity toward 2,2′-azino-bis-(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) cation radicals than did AMK. In a competition assay for hydroxyl radicals, AMMC showed prooxidant properties, whereas AMNK was a moderate antioxidant. AMMC and AMNK should represent relatively stable physiological products, although their rates of synthesis are still unknown and may be low. Formation of these compounds may contribute to the disappearance of AMK from tissues and body fluids.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1600-079X.2005.00242.x
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  • 6
    Electronic Resource
    Electronic Resource
    cis/trans-Isomerisierung von 2,2′-Diethyl-5,5′-dimethoxy-4,4′-binaphthyliden-1,1′-dion über eine radikalische Zwischenstufe (1996)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 338 (1996), S. 69-73 
    Details
    ISSN: 0941-1216
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: cis/trans-Isomerization of 2,2′-Diethyl-5,5′-dimethoxy-4,4′-binaphthylidene-1,1′-dione from a Radical IntermediateThe 1H-NMR spectrum of 2,2′-diethyl-5,5′-dimethoxy-4,4′-binaphthylidene-1,1′-dione (1) shows flat-topped peaks at room temperature. At higher temperatures sharp peaks are observed while at deep temperatures the spectrum consists of two separated sets of lines. We propose a cis/trans-isomerization with coalescence at room temperature. The rate constants of this isomerization were obtained by dynamic line shape analysis, and an energy barrier of about 74 kJ mol-1 was calculated. The intermediate biradical was proved by ESR spectroscopy.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19963380112
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  • 7
    Electronic Resource
    Electronic Resource
    Thermochromic Furofurans. IV. Approach to the synthesis of bridgehead substituted furo[3,2-b]furans and side products of McMurry reactions (1996)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 338 (1996), S. 140-145 
    Details
    ISSN: 0941-1216
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Substituted dihydroxystilbenes 2 are suitable starting materials for the synthesis of photochromic systems derived from 3/4. Attempts to couple the naphthones 8a-8e by the McMurry reaction with TiCl3/LiAlH4 yielded mainly reduction products such as 8f, g or 9. However, the furofuran 3b was isolated when using the zinc-copper couple for reduction. The helicene 11 was formed as an unexpected by-product in the McMurry reaction of the pivaloylnaphthalene 8d.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19963380127
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  • 8
    Electronic Resource
    Electronic Resource
    cycloTri-1,4-anthrachinon, ein Vorprodukt für eine neue Decastarphen-(3.3.3)-Synthese (1973)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 106 (1973), S. 2058-2069 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: cyclo-Tri-1,4-anthraquinone, an Intermediate Product for a New Synthesis of Decastarphene-(3.3.3).Anaerobic reaction of 1,4-anthraquinone (7) with small amounts of 1,4-dihydroxyanthracene (8a) gives 9a and cyclo-tri-1,4-anthraquinone (19a) (80%). Lithium aluminium hydride/boron trifluoride reduces 19a to decastarphene(3.3.3) (23); hydroiodic acid and red phosphorus transforms 19a into 24a und 25. The latter is dehydrogenated by chloranil to 23. Reductive acetylation of 19a yields 20a, the absorption maxima of which occur at shorter wave lengths than those of 23 owing to steric hindrance of the acetoxy groups.
    Notes: Aus 1,4-Anthrachinon (7) und wenig 1,4-Dihydroxyanthracen (8a) entsteht in Pyridin bei Raumtemperatur und Luftabschluß neben 9a zu 80% cyclo-Tri-1,4-anthrachinon (19a). Lithiumaluminiumhydrid/Bortrifluorid reduziert 19a zu Decastarphen-(3.3.3) (23), Jodwasserstoffsäure/roter Phosphor überführt 19a in 24a und 25, das durch Chloranil zu 23 dehydriert wird. Reduzierende Acetylierung von 19a gibt 20a, das dank sterischer Behinderung der Acetoxygruppen kürzerwellig absorbiert als 23.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19731060634
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  • 9
    Electronic Resource
    Electronic Resource
    Stoffwechselprodukte von Mikroorganismen, 172. Isolierung des Antibioticums semi-Vioxanthin aus Penicillium citreo-viride und Synthese des Xanthomegnins (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 957-978 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Metabolic Products of Microorganism, 172. Isolation of the Antibiotic semi-Vioxanthin from Penicillium citreo-viride and Synthesis of XanthomegninBesides xanthomegnin (16 b), 3,4-dehydroxanthomegnin (29a), viomellein (23) and vioxanthin (3) from Penicillium citreo-viride under different culture conditions semi-vioxanthin (7) was isolated. Structure 7 has been established by its spectra and the fact that oxidation with Fremy's salt gives 3,4,6,9-tetrahydro-10-hydroxy-7-methoxy-3-methyl-1,6,9-trioxo-1H-naphtho[2,3-c]pyran (9a = semi-xanthomegnin). -9c, prepared by demethylation of 9a, was dimerized by potassium peroxydisulfate/sodium hydroxide and methylated, giving 16b. Synthetic 16b and authentic xanthomegnin were identical, which verifies the structure revised by Höfle and Röser9) and shows, that the dyes of the xanthomegnin series are biogenetically homogenous. - The metabolic products of the strain inhibit the growth of bacteria. 16b and 26 furthermore have an effect against insects.
    Notes: Neben Xanthomegnin (16b), 3,4-Dehydroxanthomegnin (29 a), Viomellein (23) und Vioxanthin (3) wurde aus Penicillium citreo-viride unter veränderten Kulturbedingungen semi-Vioxanthin (7) isoliert. Konstitution 7 folgt aus den Spektren und dem Befund, daß mit Fremy-Salz 3,4,6,9-Tetrahydro-10-hydroxy-7-methoxy-3-methyl-1,6,9-trioxo-1H-naphtho[2.3-c]pyran (9a = semi-Xanthomegnin) entsteht. - Das durch Entmethylierung von 9a zugängliche 9c ließ sich mit Kaliumpersulfat/Natriumhydroxid zu 16a dimerisieren, das zu 16b methyliert wurde. Synthetisches 16b war mit nativem Xanthomegnin identisch, was die von Höfle und Röser9) revidierte Konstitution bestätigt und beweist, daß die Farbstoffe der Xanthomegnin-Reihe biogenetisch einheitlich sind. - Die Stoffwechselprodukte des Stammes hemmen das Wachstum von Bakterien, 16b und 23 wirken ferner gegen Insekten.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19791120319
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  • 10
    Electronic Resource
    Electronic Resource
    Dimere Naphthochinone, VII. Synthese von Rotundichinon und 2,3′-Bijuglon über halogenierte Binaphthyldichinone (1983)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1983 (1983), S. 1020-1030 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Dimeric Naphthoquinones, VII. - Synthesis of Rotundiquinone and 2,3′-Bijuglone via Halogenated BinaphthyldiquinonesAn improved synthesis of the unsymmetric quinoid-quinoid cross-linked [2,3′-binaphthyl]diquinones rotundiquinone (3a) and 2,3′-bijuglone (3c) was achieved by demethylation followed by hydrogenolytic dehalogenation starting from the monobromo derivatives 14a and 14c. Synthesis and properties of some more halogenated bijuglones are described.
    Notes: Eine verbesserte Synthese der unsymmetrisch über die chinoiden Ringe verknüpften [2,3′-Binaphthyl]dichinone Rotundichinon (3a) und 2,3′-Bijuglon (3c) geht von den leicht zugänglichen Monobromderivaten 14a und 14c aus, die sich glatt entmethylieren und anschließend hydrogenolytisch enthalogenieren lassen. Synthesen und Eigenschaften weiterer halogenierter Bijuglone werden beschrieben.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198319830614
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