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  • 1
    Electronic Resource
    Electronic Resource
    Umsetzungen α-metallierter Isocyanide mit einigen 1,3-Dipolen (1980)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1980 (1980), S. 600-610 
    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 α-Metalated Isocyanides, XLV1).  -  Reactions of α-Metalated Isocyanides with Some 1,3-DipolesReaction of α-metalated isocyanides 1a - c, f with alkylideneamine oxides (nitrones) 4 affords the 2-imidazolidinones 8. The 6-metalated 2,3-dihydro-4-H-1,2,5-oxadiazine of type 5 is postulated as decisive intermediate.  -  Benzonitrile oxide (17) reacts analogously with 1a and 1b to give 4-imidazolin-2-ones 18 and with 1e to give the 3-imidazolin-2-one 19.  -  Phenyl azide (20) reacts with two moles of 1b to give 5-(benzylideneamino)-4H,5H-1,2,3-triazoline 24. The reaction course is discussed.
    Notes: Die α-metallierten Isocyanide 1a - c, f reagieren mit den Alkylidenaminoxiden (Nitronen) 4 zu 2-Imidazolidinonen des Typs 8. Als entscheidende Zwischenstufe wird ein 6-metalliertes 2,3-Dihydro-4H-1,2,5-oxadiazin vom Typ 5 postuliert.  -  Benzonitriloxid (17) ergibt mit 1a und 1b analog die 4-Imidazolin-2-one 18, mit 1e das 3-Imidazolin-2-on 19.  -  Phenylazid (20) setzt sich mit zwei Äquivalenten 1b zum 5-Benzylidenamino-4H,5H-1,2,3-triazolin 24 um. Der Reaktions-verlauf wird diskutiert.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198019800412
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  • 2
    Electronic Resource
    Electronic Resource
    Synthese von N-Hydroxyaminosäuren durch Alkylieren von N-Benzyliden-α-aminosäure-methylester-N-oxidenHerrn Prof. Dr. L. Horner zum 70. Geburtstag gewidmet. (1981)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1981 (1981), S. 1378-1387 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of N-Hydroxy-α-amino Acids by Alkylation of N-Benzylidene-α-amino Acid Methyl Ester N-oxidesThe higher N-benzylidene-α-amino acid methyl ester N-oxides 3c-t were obtained from the lower nitrone esters 3a and b by base induced alkylation in α-position of the N→O-group. The compounds 3 were converted into the N-hydroxy-α-amino acid methyl esters 6 by heating with hydroxylamine hydrochloride in ethanol and into N-hydroxy-α-amino acids 7 with concd. hydrochloric acid. - Compound 3d was, on heating in toluene, converted to methyl 1-aza-7-oxabicyclo-[2.2.1]heptanecarboxylate 8 by intramolecular cycloaddition.
    Notes: Aus den einfachen Nitronestern 3a und b erhielt man durch baseninduzierte Alkylierung in α-Stellung zur N→O-Gruppe die höheren N-Benzyliden-α-aminosäure-methylester-N-oxide 3c-t. Durch Erhitzen mit Hydroxylamin-hydrochlorid in Ethanol gewann man daraus die N-Hydroxy-α-aminosäure-methylester 6, durch Hydrolyse mit konz. Salzsäure die N-Hydroxy-α-aminosäuren 7. - Die Verbindung 3d lieferte beim Erhitzen in Toluol durch intramolekulare Cycloaddition den 1-Aza-7-oxabicyclo[2.2.1]heptancarbonsäure-methylester 8.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198119810806
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  • 3
    Electronic Resource
    Electronic Resource
    Synthesen mit α-metallierten Isocyaniden, LII. Synthesen mit α-metallierten Isocyaniden, LII. Synthese von 2-Alkyl- und 2-Acyl-1-methylimidazol-4-carbon-säuremethylestern aus (Z)-β-Dimethylamino-α-isocyanacrylsäure-methylester und Alkyl- oder Acylhalogeniden (1982)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982), S. 2093-2095 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Syntheses with α-Metalated Isocyanides, LII1).  -  Synthesis of Methyl 2-Alkyl- and 2-Acyl-1-methylimidazole-4-carboxylates from Methyl (Z)-β-Dimethylamino-α-isocyanoacrylate and Alkyl or Acyl HalidesThe title compounds 6 and 7 were prepared from methyl (Z)-β-dimethylamino-α-isocyanoacrylate and alkyl or acyl Halides.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198219821117
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  • 4
    Electronic Resource
    Electronic Resource
    Synthesen mit α-metallierten Isocyaniden, XLIV. Notiz über β-Dimethylamino-α-isocyanacrylsäureester und ihre Verwendung in der Heterocyclenchemie (1979)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1979 (1979), S. 1444-1446 
    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 α-Metalated Isocyanides, XLIV. - Note on β-Dimethylamino-α-isocyanoacrylates and their Use in Heterocyclic ChemistryReaction of the isocyanoacetates 1a, b and N,N-dimethylformamide diethylacetal (2) afforded the β-dimethylamino-α-isocyanoacrylates 3a, b. The ethyl ester 3a and hydrogen sulfide (in the presence of triethylamine) gave the ethyl thiazole-4-carboxylate (7). The underlying principle of this reaction is electrocyclisation of an heteropentadienyl anion (namely 5) followed by elimination. Reaction of 3b with methyl iodide furnished methyl 1,2-dimethylimidazolecarboxylate 10 (or 11).
    Notes: Aus den Isocyanessigsäureestern 1a, b und N,N-Dimethylformamid-diethylacetal (2) erhielt man die β-Dimethylamino-α-isocyanacrylsäureester 3a, b. Der Ethylester 3a lieferte mit Schwefelwasserstoff (in Gegenwart von Triethylamin) Thiazol-4-carbonsäure-ethylester (7). Elektrocyclisierung eines Heteropentadienylanions (nämlich 5), gefolgt von Eliminierung ist das Grundprinzip dieser Umsetzung. - Mit Methyliodid ergab der Methylester 3b den 1,2-Dimethylimidazolcar-bonsäure-methylester 10 (oder 11).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.197919790918
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