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  • 1
    Electronic Resource
    Electronic Resource
    Synthesen mit substituierten Malonaldehyden, XXIII. γ-Cycloalkyl-pentamethincyanin-Farbstoffe (1976)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 109 (1976), S. 3005-3016 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses with Substituted Malonaldehydes, XXIIIγ-Cycloalkylpentamethinecyanine DyesCondensation of the cycloalkylmalonaldehydes 2a-d with heterocyclic imonium salts (1a-c) yields γcycloalkyl subsituted symmetric pentamethinecyanine dyes (3a-h). The introduction of a γ-cycloalkyl group causes a 2-8 nm hypsochromic (!) shift of the long wave length π-π* absorption band in the electronic spectra (table 1) according to a small (-1)-effect. This substituent effect, particularly unexpected in the case of a cyclopropyl group, suggests for the dyes 3a-c the existence of a perpendicular conformation of the cyclopropyl group relative to the all-trans pentamethine chain. This conclusion is confirmed by an X-ray analysis of 3a (fig.1-4).
    Notes: Durch Kondensation der Cycloalkylmalonaldehyde 2a-d mit heterocyclischen Imoniumsalzen (1a-c) werden γ-cycloalkylsubstituierte symmetrische Pentamethincyanin-Farbstoffe (3a-h) dargestellt. Die Einführung von γ-Cycloalkylgruppen bewirkt eine hypsochrome (!) Verschiebung der längstwelligen π-π*-Absorptionsbande um 2-8 nm im Elektronenspektrum (Tab. 1), entsprechend einem geringen (-I)-Effekt. Dieser besonders für die Cyclopropylgruppe unerwartete Substituenteneinfluß legt für die Farbstoffe 3a-c das Vorliegen einer Konformation nahe, in der die Ebene der Cyclopropylgruppe parallel zur all-trans-Pentamethinkette liegt. Eine Röntgenstrukturanalyse von 3a bestätigt diese Annahme (Abb. 1-4).
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19761090905
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  • 2
    Electronic Resource
    Electronic Resource
    Synthesen mit aliphatischen Dialdehyden, XXXVIII. Darstellung und Eigenschaften von Cycloalkylmalonaldehyden (1984)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1984 (1984), S. 649-679 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses with Aliphatic Dialdehydes, XXXVIII. - Synthesis and Properties of CycloalkylmalonaldehydesVilsmeier formylation cycloalkyl-substituted enol ethers (7, 14a - c, 23) yields the cycloalkylmalonaldehydes 1- 5 for the first time. In solution 1 - 5 with suitable electrophiles and nucleophiles leads to cycloalkyl-substituted open-chain (29, 30), carbocyclic (31) as well as heterocyclic compounds (32-40) with peculiar properties due to the presence of the lipophilic cycloalkyl group.
    Notes: Durch Vilsmeier-Formylierung cycloalkylsubstituierter Enolether (7, 14a - c, 23) werden die Cycloalkylmalonaldehydes 1 - 5 erstmals dargestellt. In Lösung liegen 1 - 5 in der (E)-s-(E)-Enolform als vinyloge Carbonsäuren vor. Reaktion von 1-5 mit geeigneten Elektrophilen und Nucleophilen führt zu cycloalkylsubstituierten offenkettigen (29, 30), carbocyclischen (31) und heterocyclischen Verbindungen (32-40) mit besonderen, durch die lipophile Cycloalkylgruppe hervorgerufenen Eigenschaften.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198419840405
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    Paper (German National Licenses)
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