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  • 1
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Durch eine eindeutig verlaufende Synthese wird bewiesen, daß Descarbomethoxy-bisanhydro-ε-rhodomycinon 1.6.11-Trihydroxy-8-äthyl-tetracenchinon-(5.12) ist und daß die zu Ring D gehörende Hydroxygruppe des α-, β-, γ-, ε- und ζ-Rhodomycinons an C-4 steht.
    Additional Material: 1 Ill.
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 1992-2004 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of Chloromethyl Methyl Ether with Chlorin DerivativesReactions of chloromethyl methyl ether with the methine bridge carbon atom 20 and the 3-vinyl group of chlorin derivatives pyropheophorbide a methyl ester 1, [3-ethyl]-pyropheophorbide a methyl ester (10) and [3-ethyl]-chlorin e6 trimethyl ester (13)〉 are described. The 20-hydroxymethyl group introduced into 13 could be reduced to methyl group with palladium/hydrogen. - The structure of the reaction products are proved by mass- and 1H-NMR spectra.
    Notes: Es werden Reaktionen von Chlormethyl(methyl)ether mit dem Methinbrücken-Kohlenstoffatom 20 und der 3-Vinylgruppe von Chlorin-Derivaten 〈 Pyrophäophorbid-a-methylester (1), [3-Ethyl]-pyrophäophorbid-a-methylester (10) und [3-Ethyl]-chlorin-e6-trimethylester (13)〉 beschrieben. Die in 13 eingeführte 20-Hydroxymethylgruppe konnte mit Palladium/Wasserstoff in eine Methylgruppe umgewandelt werden. - Durch Massen- und 1H-NMR-Spektren werden die Strukturen der Reaktionsprodukte belegt.
    Additional Material: 1 Ill.
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  • 3
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Note on a Simple Method for the Separation of Chlorophyll Derivatives of the a- and b-SeriesAn efficient, fast, and inexpensive method for the separation of metal-free derivatives of chlorophyll a (1) and chlorophyll b (2) in gram quantities, exemplified by the phaeophorbide a (or b) methyl esters (3) or (4), is described. This method is based on the partition between aqueous formic acid and tetrachloromethane. 3 and 4 are valuable key intermediates for preparative and spectroscopic studies.
    Notes: Am Beispiel der Phäophorbid a/b-Methylester (3) bzw. (4) wird eine leistungsfähige, schnelle und preiswerte Trennmethode für metallfreie Derivate der Chlorophylle a (1) und b (2) im Gramm-Maßstab vorgestellt, die auf der Verteilung zwischen wäßriger Ameisensäure und Tetrachlorkohlenstoff beruht. 3 und 4 sind wertvolle Schlüsselbausteine für präparative und spektroskopische Arbeiten.
    Additional Material: 1 Ill.
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  • 4
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Regioselective Syntheses of 3,3′-Bijuglone, Mamegakinone, Dianellinone, cyclo-Trijuglone, Xylospyrin and Trianellinone by Phenol-Quinone AdditionRegioselective phenol-quinone addition of juglone (1a), 7-methyljuglone (1b), and stypandrone (1c) in pyridine yields the dimers 3,3-bijuglone (5a), mamegakinone (5c), and dianellinone (5e). In acetic acid mainly the cyclo trimers cyclo-trijuglone (12a), xylospyrin (12d), and trianellinone (12g) are obtained
    Notes: Durch regioselektive Phenol/Chinon-Addition werden aus Juglon (1a), 7-Methyljuglon (1b) und Stypandron (1c) in Pyridin die Dimeren 3,3′-Bijuglon (5a), Mamegakinon (5c), Dianellinon (5e) und in Eisessig die cyclo-Trimeren cyclo-Trijuglon (12a), Xylospyrin (12d) und Trianellinon (12g) synthetisiert.
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1988 (1988), S. 1-7 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: cyclo-Trimerisation of 1,4-Naphthoquinone; Cooperation of Phenol/Quinone Additions and Redox ReactionsThe reaction course2) postulated for the cyclo-trimerisation of 1,4-naphthoquinone (1a) to cyclo-tri-1,4-naphthoquinone (11a) is confirmed and supplemented by: (i) isolation of the red intermediate 1′,4′-dihydroxy-2,2′-binaphthyl-1,4-quinone (5a), (ii) synthesis of 11a starting from 5a or 2,2′-binaphthyl-1,4:1′,4′-diquinone (6a), and (iii) reduction of 5a and 6a by 1,4-naphthalenediol (2a) to 2,2′-binaphthyl-1,1′,4,4′-tetrol (4a). Requirement for the cyclo-trimerisation of 1a to 11a is a cooperation of phenol/quinone additions and redox reactions controlled by the permanent decreasing oxidation potential of the reaction mixture. As byproducts of the synthesis of 11a in acetic acid 9a, 10a, 12a, 12c, 13a, 13c, and 14a could be isolated as acetates.
    Notes: Der für die cyclo-Trimerisierung von 1,4-Naphthochinon (1a) zu cyclo-Tri-1,4-naphthochinon (11a, Triphthaloylbenzol) postulierte Reaktionsverlauf2) wurde bestätigt und ergänzt durch: 1. Isolierung des roten Zwischenproduktes 1′,4′-Dihydroxy-2,2′-binaphthyl-1,4-chinon (5a), 2. Synthese von 11a, ausgehend von 5a oder 2,2′-Binaphthyl-1,4:1′,4′-dichinon (6a). 3. Reduktion von 5a und 6a durch 1,4-Naphthalindiol (2a) zu 2,2′-Binaphthyl-1,1,′4,4′-tetrol (4a). Vorbedingung für die cyclo-Trimerisierung von 1a zu 11a ist ein Kooperieren, von Phenol/Chinon-Additionen und Redoxreaktionen, das gesteuert wird durch das laufend kleiner werdende Oxidationspotential der Reaktionslösung. Bei der Synthese von 11a in Eisessig wurden die Nebenprodukte 9a, 10a, 12a, 12c, 13a, 13c und 14a als Acetate isoliert.
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982), S. 472-479 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Partial Synthesis of an [3-Ethyl]-bacteriopheophorbide c Methyl Ester1)The partial synthesis of [3-ethyl]-bacteriopheophorbide c [Et-Me] methyl ester (8′) is described starting from chlorine e6 trimethyl ester (1) which is easily accessible from chlorophyll a. 8′ is compared with a derivative of bacteriochlorophyll c, thus the structure of the latter is proved also by synthesis.
    Notes: Es wird die Partialsynthese des [3-Ethyl]-bacteriophäophorbid-c-[Et-Me]-methylesters (8′) aus Chlorin-e6-trimethylester (1) beschrieben, das seinerseits leicht aus Chlorophyll a zugänglich ist. 8′ wird mit einem aus Bacteriochlorophyll c erhältlichen Derivat verglichen, womit dessen Konstitution auch durch Synthese gesichert ist.
    Additional Material: 1 Tab.
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1988 (1988), S. 343-347 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Bacteriochlorophyll f. - Partial Synthesis and the Behaviour of Some DerivativesStarting with chlorophyll a/b mixture 5/6 from green plants, we describe the partial synthesis of the bacteriophaeophorbide f methyl ester 7. This is a derivative of bacteriochlorophyll f (4). We postulate the existence of 4 as a natural product, though it has not yet been isolated. Methods for the separation of the epimeric compounds 7 are described.
    Notes: Wir beschreiben die Partialsynthese des Bacteriophäophorbid-f-methylesters 7 ausgehend vom Chlorophyll-a/b-Gemisch 5/6 aus grünen Pflanzen. 7 ist ein Derivat des von uns postulierten, in der Natur jedoch noch nicht entdeckten Bacteriochlorophylls f (4). Verfahren zur Epimerentrennung von 7 werden beschrieben.
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  • 8
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die Isolierung aller bei Totalhydrolyse entstandenen Abbauprodukte hat gezeigt, daß Valinomycin aus 2 Moll. L-Valin, 2 Moll. D-Valin, 2 Moll. L-Milchsäure und 2 Moll. D-α-Hydroxy-isovaleriansäure aufgebaut ist. Partiathydrolyse des Valinomycins mit Bariumhydroxyd lieferte 1.7 Mol L-Lactyl-L-valin und 1.7 Mol D-α-Hydroxy-isovaleryl-D-valin. Aus diesen Befunden und der Tatsache, daß Valinomycin keine Hydroxy-, Amino- und Carboxygruppen enthält, ergibt sich eine Strukturformel, in der zwei L-Lactyl-L-valyl- und zwei D-α-Hydroxy-isovaleryl-D-valyl-Reste durch Ester- bzw. Säureamidbindungen zu einem 24-gliedrigen Ring verknüpft sind.
    Additional Material: 3 Ill.
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 754 (1972), S. 139-148 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Absolute Configuration of Chlorophylls, V. The Absolute Configuration of Chlorophylls a and bVarious possibilities of establishing the absolute configuration of chlorophylls a and b are discussed. Chromic acid degradation of methylpheophorbide a (1a) yields (+)-tri-p-bromophenacyl 2(S), 3(S)-dihydrohematinate (4), and thus 7(S).8(S)-configuration of chlorophylls a and b is proven.
    Notes: Verschiedene Möglichkeiten zur Bestimmung der absoluten Konfiguration von Chlorophyll a und b werden diskutiert. Beim Chromsäure-Abbau von Methylphäophorbid a (1a) entsteht (+)-2(S).3(S)-Dihydrohämatinsäure-tri-p-brom-phenacylester (4), wodurch die 7(S).8(S)-Konfiguration der Chlorophylle a und b bewiesen ist.
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1978 (1978), S. 585-594 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Chromatographic Separation and Characterization of the Bacteriomethylphaeophorbides eThe solution of a difficult separation problem concerning various methylphaeophorbides 4 from bacteriochlorophyll e (mixture 1) of Chlorobium phaeovibrioides by using adsorbents of small particle size and improved chromatographic techniques is demonstrated. The components of 4, obtained for the first time in pure form, are unambiguously characterized and their mass- and 1H-NMR spectra are discussed.
    Notes: Die Lösung eines schwierigen Trennproblems durch den Einsatz von Adsorbentien geringer Korngröße und verbesserter chromatographischer Techniken wird am Beispiel der Methylphäophorbide e 4 des Bacteriochlorophylls e (Gemisch 1) aus Chlorobium phaeovibrioides beschrieben. Die erstmals in reiner Form erhaltenen Komponenten von 4 werden eindeutig charakterisiert und ihre Massen- und 1H-NMR-Spektren diskutiert.
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