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  • 1
    Electronic Resource
    Electronic Resource
    Synthese von substituierten 2-(Ethoxycarbonyl-formyl-methylen)-2H-benzopyranen und ihre Überführung in Polymethinderivate (1994)
    Springer
    Monatshefte für Chemie 125 (1994), S. 61-70 
    Details
    ISSN: 1434-4475
    Keywords: 3-Chloro-2-ethoxycarbonyl crotonic aldehyde ; 2H-Benzopyrans ; Pyrylium salts ; Polymethin dyes ; Grob-Fragmentation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary 3-Chloro-2-ethoxycarbonyl crotonic aldehydeC reacts with several 2-hydroxybenzene carbaldehydes and 2-hydroxy-naphthalene-1-carbaldehyde, respectively, to give 2-(ethoxycarbonyl-formyl-methylene)-2H-benzopyrans1a–h under mild conditions. With exception of1c and1d these compounds are mixtures ofE–Z isomers.1a–h easily undergo reactions, e.g. with aniline and derivatives to give2a–e, with various CH-acidic compounds to give3a–h and with 2-alkyl-4,6-diphenyl pyrylium salts to give4a–e. In the presence of alcoholic hydrochloric acid, compounds1 are converted into symmetrical 2,2′-benzopyrylotrimethine salts5a–e which exhibit longwave absorptions from 640–705 nm. These polymethine dyes with ester groups in the methine chain exhibit a remarkable thermal stability.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00811675
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  • 2
    Electronic Resource
    Electronic Resource
    Synthese neuer, 3-substituierter 2H-Thiopyran-Derivate via [4+2]-Cycloaddition mittels acceptorsubstituierter Enaminothione (1994)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 336 (1994), S. 434-438 
    Details
    ISSN: 0941-1216
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis of New 3-Substituted 2H-Thiopyran Derivatives via [4+2] Cycloaddition Reactions using Acceptor Substituted Enaminothiones3- and 4-Nitro acetophenones as well as 3- and 4-trifluoromethyl acetophenones react with POCl3/DMF (Vilsmeier reagent) to give dimethyliminium perchlorates 1a-d after addition of perchloric acid to the reaction mixture. Substitution of the chloro atom in 1 by using sodium sulfide nonahydrate occurs under mild conditions (in case of nitro compounds at -5°C) leading to enaminothiones 2a-d. Reactions with acroleine and methylvinylketone in refluxing benzene give exclusively 2H-thiopyran derivatives 4a-h, which were isolated in good yields after spontaneous fast elimination of dimethylamine. In contrast, the introduction of 1-nitro-2-phenylethene as the dienophile allows stepwise reaction to give stable adducts 3k and 3l, respectively, and also 3m under mild conditions (reaction at room temperature). 1H n.m.r. spectroscopic data as well as the elimination of dimethylamine to 4k-m permit the elucidation of the structure of adducts 3k-m.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19943360510
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  • 3
    Electronic Resource
    Electronic Resource
    Zur Synthese CF3-substituierter Chinoline aus β-Chlor-β-trifluormethyl-vinylaldehyden. I (1995)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 337 (1995), S. 34-37 
    Details
    ISSN: 0941-1216
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis of CF3-Substituted Quinolines from β-Chloro-β-trifluoromethyl-vinylaldehydes. I3-(Trifluoromethyl)-acroleines 2 have been synthesized through VILSMEIER's reaction from α-Trifluoro-methylketones 1. The reaction of 2 with anilines and naphthylamines gives in good yields 2-trifluoromethylquinolines 4 and benzoquinolines 5.
    Additional Material: 6 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19953370107
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  • 4
    Electronic Resource
    Electronic Resource
    Vilsmeier-Reaktion an Dimedon (1979)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 321 (1979), S. 671-674 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Vilsmeier-Reaction on Dimedone.The Vilsmeier-reaction has been studied in detail for a special cyclic β-diketone, dimedone. It was shown, that the first step in this reaction is the formation of the corresponding β-chlorovinylketone. 3-Chloro-5,5-dimethyl-cyclohex-2-en-one-(1) 2, 2,4-dichloro-6,6-dimethyl-1-formyl-cyclohexa-1,3-diene 3 und 2,4-dichloro-1,5-diformyl-6,6-dimethyl-cyclohexa-1,4-diene 4 were isolated in equal parts. The symmetrical enolether 6 was identified as condensation-product of the diformylated compound 5.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19793210420
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  • 5
    Electronic Resource
    Electronic Resource
    Reaktionen von β-Chlorvinylaldehyden, III. Synthese und Eigenschaften von β-Thioketoaldehyden (1973)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 315 (1973), S. 873-880 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: β-Thioketoaldehyde 1 werden durch Umsetzungen von β-Chlorvinylaldehyden mit Na2S · 9 H2O präparativ dargestellt. Von den möglichen tautomeren Formen dominiert im Gleichgewicht sowohl im festen Zustand als auch in Schwefelkohlenstofflösung der Enthiolaldehyd. Zur Charakterisierung eignen sich die leicht zugänglichen Nickelchelate. Folgereaktionen von 1 mit Phenylhydrazin, Anilin, Alkylhalogeniden und α-Halogencarbonylverbindungen führen zu Pyrazolen, S-haltigen SCHIFFschen Basen, Alkylmercaptovinylaldehyden und Thiophenen, die im einzelnen beschrieben werden.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19733150509
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  • 6
    Electronic Resource
    Electronic Resource
    Synthese und Struktur von Imino-bis[1]benzothiopyrano[4,3-b: 4,3-f] [1,5]dithiocinenHerrn Professor Dr. Rolf Borsdorf in Verbundenheit herzlichst zu seinem 60. Ge- (1991)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 333 (1991), S. 849-854 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis and Structure of Imino-bis[1]benzothiopyrano[4,3-b:4,3-f][1,5]dithiocinesSeveral substituted 3-Alkyl- respectively 3-Aryl-aminomethylene-2H-[1]benzothiopyran-4-thiones undergo a thermal reaction yielding the light yellow title compounds 2. For the mechanism of this reaction we propose a condensation reaction of the starting compounds 1 loosing one molecule of amine in the first step followed by electrocyclisation reactions of the intermediates to products 2. The structure of compounds 2 is elucidated by 1H nmr spectroscopy and also x-ray analysis in case of compound 2b.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19913330606
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