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  • 1
    Electronic Resource
    Electronic Resource
    Anodic Cyanation of N-Substituted 1-Benzazepines: Synthesis of the Corresponding α-Aminonitriles (1997)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1997 (1997), S. 259-267 
    Details
    ISSN: 0947-3440
    Keywords: Electrochemistry ; Anodic cyanation ; 1-Benzazepines ; α-Aminonitriles ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: α-Cyano-N-alkyl-1-benzazepines are obtained by electrochemical oxidation of various 1-benzazepines. Electrolyses are carried out in a flow cell, at a carbon felt anode in methanol; the supporting electrolyte is a mixture of lithium acetate and sodium cyanide. With 2,3,4,5-tetrahydrobenzazepines 2a-c and 5a-b, cyanation takes place either on the sidechain or on the seven-membered ring; with the latter, the 3-methyl substituted derivatives 5a-b, the reaction is stereospecific leading only to the trans-α-cyano compound. With dihydrobenzazepines 8a-b only ring cyanation occurs; the reaction is again stereospecific for 2,3-dihydro-1,3,5-trimethylbenzazepine (8a) but not for the 2,5-dihydro-1,3,5-trimethyl isomer (8b).
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199719970137
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  • 2
    Electronic Resource
    Electronic Resource
    Electrosynthesis of α-Aminonitriles: Anodic Cyanation of N-Substituted Tetrahydroquinolines and N-PhenylpiperidinesDedicated to Professor Hans Schäfer on the occasion of his 60th birthday. (1997)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1997 (1997), S. 2089-2101 
    Details
    ISSN: 0947-3440
    Keywords: Nitrogen heterocycles ; Nucleophilic additions ; Electrochemistry ; C—C Bond formation ; α-Aminonitrile synthesis ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The electrochemical cyanation of N-alkyl-substituted cyclic six-membered amines including N-alkyl-1,2,3,4-tetrahydroquinoline and N-phenylpiperidine derivatives has been investigated. The reaction gives the corresponding α-aminonitriles and was carried out at a graphite felt anode percolated with a methanolic solution of the amine, containing six equivalents of sodium cyanide per mol of substrate, and lithium acetate as the supporting electrolyte. In the case of N-substituted tetrahydroquinolines 1a-f, cyanation occurs regioselectively at the ring and the position of substitution depends on the nature of the N-alkyl substituent. The stereoselectivity of the cyanide addition was investigated using various 3-methyltetrahydroquinolines 8a-c as substrates. In all cases, the major stereoisomers 9a-c possess a cis configuration in which the 2-cyano group has an axial disposition and the 3-methyl group is equatorial. In a similar fashion, various N-phenylpiperidines substituted at the ring by either one or two methyl groups were oxidized. In all the selected amines the introduction of the cyanide group occurs stereospecifically in the position α to the nitrogen atom. The cis or trans relative configuration of the cyanated compounds is discussed separately for each substrate. It is noteworthy that in all cases the cyano group was in an axial position.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199719971011
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  • 3
    Electronic Resource
    Electronic Resource
    Regio- and Diastereoselective Synthesis of α-Cyanoamines by Anodic Oxidation of 6-Membered α-Silylamines (1999)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1999 (1999), S. 2645-2653 
    Details
    ISSN: 1434-193X
    Keywords: C-C coupling ; α-Cyanoamines ; Electrochemistry ; Iminium cation ; α-Silylamines ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The electrochemical cyanation of N-benzyl-substituted cyclic six-membered α-silylamines including tetrahydroquinoline and piperidine derivatives was studied. The results of these investigations demonstrate that α-silylamines are valuable precursors for the preparation of the corresponding α-cyanoamines. The TMS group α to the N atom not only governs the chemoselectivity of the iminium formation through a preferential desilylation reaction under the experimental conditions (i.e., amine cation radical desilylation versus deprotonation), it also lowers the oxidation potential of tertiary amines compared to their non-TMS counterparts. Both the stereoselectivity and regioselectivity of the cyanide addition were investigated with 3-methylpiperidine as the model compound. The formation of a single cisdiastereoisomer in which the 2-cyano group is axial and the 5-methyl group is equatorial, indicates that the addition of the cyanide anion onto the iminium species is under stereoelectronic control. In addition, the redox reaction involving the intermediate nitrogen-centered cation radical and the cyanide anions played no role, because the α-silyl radical has such a short lifetime.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
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