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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Cardiovascular drug reviews 11 (1993), S. 0 
    ISSN: 1527-3466
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 745-758 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Deamination Reactions, 21. Reactions of Alihatic Diazonium Ions with AminesAliphatic diazonium ions react with dimethylamine to give N, N-dimethylalkylamines. As compared to previously studied reactions of the diazonium ions with alcohols, dimethylamine behaves as a weakly polar and strongly nucleophilic solvent. The rearrangements of alkyl-, allyl-, and cyclopropyldiazonium ions are minimized; the configurational inversion of 1-phenylethyldiazonium ions is increased. The substitution of trans- and cis-2-methylcyclo-propyldiazonium ions (34 and 35) afforded nearly identical mixtures of trans- and cis-dimethyl(2-methylcyclopropyl)amine(37 and 38), probably by way of a cyclopropyl cation (36). In addition to substitution, cyclopropyldiazonium ions undergo azo coupling to afford 1-cyclopropyl-3-alkyltriazenes (39, 40). No triazenes were obtained from methyl- and isobutyldiazonium ions under identical conditions.
    Notes: Aliphatische Diazonium-Ionen reagieren mit Dimethylamin unter Bildung von N, N-Dimethylalkylaminen. Im Vergleich zu den früher untersuchten Umsetzungen der Diazonium-Ionen mit alkoholen verhält sich Dimethylamin als schwach polares und stark nucleophiles Lösungsmittel. Umlagerungen von Alkyl-, Allyl- und Cyclopropyldiazonium-Ionen werden unterdrückt, die Konfigurationsumkehrung bei 1-Phenyläthyldiazonium-Ionen erhöht. Die Substitution von trans- und cis-2-Methycyclopropyldiazonium-Ionen(34 und 35) ergab nahezu identische Gemische von trans- und cis-Dimethyl(2-methylcyclopropyl)amin (37 und 38); sie verläuft wahrscheinlich über ein Cyclopropylkation (36). Neben der Substitution zeigen Cyclopropyldiazonium-Ionen auch Azokupplung zu 1-Cyclopropyl-3-alkyltriazenen (39, 40); aus Methyl- und Isobutyldiazonoium-Ionen wurden unter den gleichen Bedingungen keine Triazene erhalten.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 105 (1972), S. 850-858 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Deamination Reactions, XIII Deuterated Allyldiazonium Ions and Allyl CationsThe terminally deuterated allyl cation (6) has been generated by cleavage of cyclopropyldiazonium ion-2-d1 (4); its reaction with methanol proceeds with kH/kD = 0.95. Allyl-diazonium ion-3-d1 (10), generated from N-nitrosoN-(3-d1-allyl)urea (9), and allyldiazonium ion-1-d1 (11), generated from vinyldiazomethane and deuterated acids, afforded products with strongly asymmetric distributions of deuterium. Variation of the solvent has no measurable effect (〈10%) on the deuterium distribution, in contrast to addition of the solvent anion. Substituent effects on the behavior of primary allyldiazonium ions are summarized.
    Notes: Das endständig deuterierte Allylkation 6 wurde durch Ringöffnung des Cyclopropyldiazonium-Ions-2-d1 (4) erzeugt; es zeigt bei der Reaktion mit Methanol KH/KD = 0.95. Allyldiazonium-Ion-3-d1 (10), aus N-Nitroso-N-[3-d1-allyl]-harnstoff (9), und Allyldiazonium-Ion-1-d1 (11), aus Vinyldiazomethan und deuterierten Säuren, liefern dagegen Produkte mit stark unsymmetrischer Deuteriumverteilung. Variation des Lösungsmittels beeinflußt die Deuteriumverteilung nicht nachweisbar (〈10%), wohl aber Zusatz des Solvens-Anions. Der Substituenten-Einfluß auf das Verhalten primärer Allyldiazonium-Ionen wird zusammen-fassend diskutiert.
    Additional Material: 6 Tab.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 722-728 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reversal of the Diastereoselectivity in the Hydride Reduction of Acyclic Diketones3,3-Dimethyl-2,4-pentanedione (2a) is reduced to mixtures of diols 1a and 3a by a variety of hydride reagents in different solvents, the d,l-isomer 1a predominating in most cases. Addition of titanium tetrachloride reverses the diastereoselectivity favouring the formation of meso-diol 3a. All induction phenomena can be explained by a cyclic model.
    Notes: 3,3-Dimethyl-2,4-pentandion (2a) wird durch eine Reihe von Hydridreagenzien in unterschiedlichen Lösungsmitteln zu Gemischen der Diole 1a und 3a reduziert, wobei in den meisten Fällen das d,l-Isomere 1a überwiegt. Zugabe von Titantetrachlorid kehrt die Diastereoselektivität um und begünstigt die Entstehung des meso-Diols 3a. Alle Induktionsphänomene sind durch ein cyclisches Modell erklärbar.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 0009-2940
    Keywords: Asymmetric induction ; TiCl4 complexes ; Solid-state 13C-NMR spectra ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Solid-state 13C-NMR Spectroscopy, 1.  -  Titanium Tetrachloride Complexes of Diketones: Their Importance for Hydride Reductions and Their Solid-State NMR SpectraHerrn Prof. Christoph Rüchardt zum 65. Geburtstag gewidmet.The influence of titanium tetrachloride on the diastereoselectivity of hydride reductions of 1,2-, 1,3-, 1,4- and 1,5-diketones has been studied. The effect is especially pronounced in the case of 1,3-diketones, where the addition of titanium tetrachloride reverses the stereoselectivity. The assumption of a chelate of type 32 or 33 can be confirmed by several observations: β-hydroxy ketone 7 and β-benzyloxy ketone 9 show the same dependence on the stereochemical course as diketone 5a. This compound forms complex 34, whose conformation is known by X-ray structure determination. From the solid-state 13C-NMR spectra of the TiCl4 adducts it can be deduced that 7 forms chelate 42, which is close to the assumed intermediate 32. In the case of phenyl-substituted substrates solid-state 13C-NMR spectroscopy can also be used to differentiate between real chelates (coordination of TiCl4 at the oxygen atoms of the carbonyl groups) and π complexes.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 85 (1973), S. 994-994 
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 12 (1973), S. 924-925 
    ISSN: 0570-0833
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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