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  • 1
    ISSN: 0009-2940
    Keywords: Azabarbaralane ; Barbaralane ; Cope rearrangement ; Dynamic NMR ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Applications of13C-NMR Spectroscopy, XXVIII.  -  Activation Parameters of the Rearrangement of 1,5-Dimethyl-3,7-diethoxy-2,4,6,8-tetraazabarbaralaneThe degenerate Cope rearrangement of 3,7-diethoxy-1,5-dimethyl-2,4,6,8-tetraazabarbaralane has been studied in the temperature range between 192 and 242 K using dynamic 13C NMR spectroscopy. From the line-shape analysis the following Arrhenius and Eyring activation parameters have been derived: Ea = 10.4 kcal mol-1, lg A = 13.8; ΔH≠ = 9.94 kcal mol-1, ΔS≠ = 3.4 cal K-1, mol-1, and ΔG298≠ = 8.93 kcal mol-1. From a comparison with the free energies of related systems it can be concluded that tetraaza-substitution in 2,4,6,8-position slightly reduces the barrier of the Cope rearrangement of barbaralane.
    Notes: Die entartete Cope-Umlagerung von 3,7-Diethoxy-1,5-dimethyl-2,4,6,8-tetraazabarbaralan wurde mittels dynamischer 13C-NMR-Spektroskopie im Temperaturbereich von 192 bis 242 K untersucht. Aus der NMR-Linienformanalyse ergaben sich folgende Aktivierungsparameter nach Arrhenius und Eyring: Ea = 10.4 kcal mol-1, lg A = 13.8; ΔH≠ = 9.94 kcal mol-1, ΔS≠ = 3.4 cal K-1 mol-1 und ΔG298≠ = 8.93 kcal mol-1. Aus dem Vergleich mit Freien Aktivierungsenthalpien verwandter Systeme kann gefolgert werden, daß Tetraaza-Substitution in 2,4,6,8-Stellung die Barriere der Cope-Umlagerung von Barbaralan geringfügig erniedrigt.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0941-1216
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of bis(vinamidinium salts) (5a, 6) and amidinium-vinamidinium salts (7, 21) with primary amines was studied. Whereas the condensation of 6 and 7a with p-phenylenediamine and 4,4′ diaminostilbene gave rise to polymeric vinamidines (12, 18), 5a and 7b reacted with aromatic amines and diamines to give pyrrole and imidazole derivatives. The reaction of p-aminophenylacetic acid with DMF-POCl3 produced a new amidinium-vinamidinium salt (21) which could be converted into a donor-acceptor substituted diazaterphenyl derivative (22) displaying a strong solvatochromism. - The crystal structure analysis of the 2,2′-bis(vinamidinium salt) 5b revealed a 73° twist angle between the planes of the vinamidinium moieties.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Donor Substituted 2,4-Diazacyclopentadienones and Indigoid 1,3,5,7-TetraazafulvalenesHydrolysis of tris(diethylamino)imidazolylium chloride gives rise to 2,5-bis-diethyl-amino-4H-imidazolin-4-one; thiolysis leads, depending on conditions, to 2,5-bis-diethylamino-4H-imidazolin-4-thione or potassium 2,6-bis-diethylamino-1,3,5,7-tetraazafulvalene-4,8-dithiolate. The latter can be protonated to form green 2,6-bis(dimethylamino)-3,4,7,8-tetrahydro-1,3,5,7-tetraaza-fulvalen-4,8-dithione, a new indigoid compound, and alkylated to give blue 2,6-bis-diethylamino-4,8-bis-alkylthio-1,3,5,7-tetraazafulvalenes. Treatment of 2,5-bis-diethylamino-4H-imidazolin-4-thione with copper furnishes 2,6,4,8-tetrakis-diethylamino-1,3,5,7-tetraazafulvalene. - Oxidation of 2,6-bis-dimethylamino-3,4,7,8-tetrahydro-1,3,5,7-tetraazafulvalen-4,8-dithione gives rise to (2,2′-bis-diethylamino-4,4′-bi(4H-imidazol)-5,5′-dithione, corresponding to dehydroindigo, and reduction leads to a colorless compound, corresponding to leucoindigo.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 1388-1405 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cycloadditions with Dipolar Intermediates, I. - Syntheses and Reactions of Electron-poor AllenesThe allenetetracarboxylates 19a-c and the allenetri-, allenedi-, and allenemonocarboxylates 19d - f can be prepared: a) from e. g. bis(alkoxycarbonyl)ketenes and dialkyl (triphenylphosphoranylidene)malonates; b) from the dipolar “allene adduct” 15 formed from 4-dimethylamino-pyridine and bis(ethoxycarbonyl)ketene via the isolable “ketene pyridine dipole” 14. - Compound 19a adds water, methanol, and pyrrolidine; dimethyl malonate/sodium hydride gives rise to the salt 13 with a Y-shaped dianion. Dimethyl sulfoxide oxidizes 19a to the allene epoxide 34. Ynamines, tropone, and cyclopentadiene react with 19a to give cycloadducts.
    Notes: Die Allentetracarbonsäureester 19a-c sowie die Allentri-, Allendi- und Allenmonocarbonsäureester 19d-f werden hergestellt: a) z. B. aus Bis(alkoxycarbonyl)ketenen und (Triphenylphosphoranyliden)malonsäure-dialkylestern; b) aus dem dipolaren „Allen-Addukt“ 15, das aus 4-Dimethylaminopyridin und Bis(ethoxycarbonyl)keten über den isolierbaren „Keten-Pyridin-Dipol“ 14 entsteht. - Die Verbindung 19a addiert Wasser, Methanol und Pyrrolidin; mit Malonsäureester/Natriumhydrid entsteht das Salz 23 mit einem Y-förmigen Dianion. Dimethylsulfoxid oxidiert 19a zum Allenepoxid 34. Inamine, Tropon und Cyclopentadien reagieren mit 19a zu Cycloaddukten.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die Umsetzung von Formamid mit Aceton bei 300 über Al2O3 führt in guter Ausbeute zu einer kristallinen Verbindung C12H23O2N5. Durch zahlreiche chemische Umsetzungen wurde, unter Zuhilfenahme der IR-Spektren, für diese Verbindung die Konstitution des N-(α-Amino-isobutyryl)-N'-(2-imino-3.5.5-trimethyl-3-pyrrolidinyl)-harnstoffs (A) ermittelt.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 1406-1425 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Cycloadditions with Dipolar Intermediates, II. - Dipolar Products from AllenecarboxylatesThe allenecarboxylates 2c-c, and in some cases also the allenetri- and allenedicarboxylates 2d and 2e, f react with phosphanes, pyridines, and nucleophilic carbenes or their precursors to give the dipolar 1:1 adducts 10, 11 and 16,18, 20, respectively. These “carbene allene dipoles” represent stable derivatives of trimethylenemethane.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1980 (1980), S. 229-240 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation of Anionic Transition Metal Complexes by Alkali Metal Adducts of Aromatic HydrocarbonsThe alkali metal adducts of aromatic hydrocarbons 4 (such as naphthalene, phenanthrene or anthracene) are reagents for reducing dinuclear complexes 1 to anionic metalcarbonyl complexes 2. By this method sodium carbonylcyclopentadienylniccolate (2e) can also be obtained on a preparative scale, thus providing an entry to new derivatives of carbonylcyclopentadienyl-nickel (such as the triphenyltin derivative 9a, and acyl complexes 9b - d). For more easily reducible complexes, benzophenone-lithium (4d-Li) or the dilithium adduct 6 of benzophenone can be used, which are especially suited for the reduction of pentacarbonyliron (5) to tetracarbonylferrate (7).
    Notes: Die Alkalimetalladdukte aromatischer Kohlenwasserstoffe 4 (z. B. Naphthalin, Phenanthren oder Anthracen) eignen sich zur Herstellung der anionischen Metallcarbonyl-Komplexe 2 aus den zwei-kernigen Komplexen 1. So ist in präparativem Maßstab auch Natrium-carbonylcyclopentadienyl-niccolat (2e) zu erhalten, mit dem neue Derivate des Carbonylcyclopentadienylnickels (z. B. das Triphenylzinn-Derivat 9a sowie die Acylkomplexe 9b  -  d) zugänglich werden. Für leichter reduzierbare Komplexe sind Benzophenon-lithium (4d-Li) oder das Dilithium-Addukt 6 des Benzophenons verwendbar, die sich besonders zur Reduktion von Pentacarbonyleisen (5) zum Tetracar-bonylferrat (7) eignen.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 626 (1959), S. 83-91 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die Kern-und Seitenkettenhalogenierung, insbesondere die Bromierung, substituierter Oxazole sowie die einiger Imidazole und Thiazole wird beschrieben.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: α.β-Ungesättigte β-Amino- und β-Hydroxy-carbonylverbindungen  -  offenkettige Aldehyde, Ketone, Ester, cycloaliphatische und heterocyclische Derivate sowie Vertreter der Chinonreihe  -  liefern mit Dischwefeldichlorid vornehmlich Sulfide, mitunter auch Disulfide. Sulfide entstehen auch mit Schwefeldichlorid, Morpholin-N-sulfenylchlorid, Bis-dimethylamino-sulfid und Thionylchlorid. - Umsetzungen der so hergestellten Sulfide und Disulfide führen zu heterocyclischen Sulfiden, Disulfiden und Mercaptanen (Pyrimidinen, Pyrazolen und Isoxazolen), zu 1.4-Oxathiinen und zu Anilen der Sulfide und Disulfide von β-Arylamino-acroleinen.
    Additional Material: 1 Tab.
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  • 10
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die aus Phenolen mit CS2 und Alkali erhältlichen Salze aromatischer o- und p-Hydroxy-dithiocarbonsäuren reagieren mit äthylenbromid zu Ketenmercaptalen der Chinonmethidreihe. Der Verlauf (O.S.- oder S.S-Dialkylierung) der Umsetzung dieser Salze mit einfachen Alkylierungsmitteln (Dimethylsulfat) hängt vom aromatischen Charakter des Ringsystems ab. Mit 1.1-Dichlor-alkanen entstehen 1.3-Dithia-cyclobutane, die Oxydation liefert 1.2.4-Trithiacyclopentane der Chinonmethidreihe.  -  Aromatische Hydroxy- und Methoxydithiocarbonsäureester lassen sich mit Dimethylsulfat in Dithiocarboxoniumsalze umwandeln; mittels Triäthylamins werden aus den Hydroxy-onium-Salzen ω.ω-Bis-methylmercapto-chinonmethide in Freiheit gesetzt.  -  Die ω.ω-Bis-alkylmercapto-chinonmethide zeigen positive Solvatochromie. Ihre Dipolmomente liegen in der Gröβenordnung von 5 D.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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