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  • 1
    Electronic Resource
    Electronic Resource
    Cyanamidiumsalze aus Isocyaniden und N-Chloraminen (1983)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 1834-1847 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cyanamidium Salts from Isocyanides and N-ChloroaminesCyanamidium hexachloroantimonates (2a-g) are isolated in 60-80% yield from the reaction of aryl or alkyl isocyanides (6) with N-chlorodialkylamines (5) and antimony pentachloride at low temperature. Polymerization of the isocyanides which is catalysed by antimony pentachloride is avoided through complexation with zinc- or mercury(II) chloride. The cyanamidium salts (2) react with alcohols to give tetrasubstituted uronium hexachloroantimonates (15a-s) from which isoureas (17) are obtained with base. Uronium salts (15) are also prepared from the reaction of isocyanide dichlorides (18) with N-chloroamines (5), antimony pentachloride and alcohols. Tetra- and pentasubstituted guanidinium hexachloroantimonates (16a-r) are obtained from cyanamidium salts (2) and primary or secondary amines.
    Notes: Aryl- und Alkylisocyanide (6) reagieren mit N-Chlordialkylaminen (5) und Antimonpentachlorid bei tiefen Temperaturen in Ausbeuten von 60-80% zu den isolierbaren Cyanamidium-hexachloro-antimonaten (2a-g). Die durch Antimonpentachlorid beschleunigte Polymerisation der Isocyanide läßt sich durch Komplexierung mit Zink- oder Quecksilber(II)-chlorid verhindern. Die Cyanamidiumsalze (2) reagieren mit Alkoholen zu tetrasubstituierten Uronium-hexachloro-antimonaten (15a-s), aus denen mit Base die Isoharnstoffe (17) freigesetzt werden können. Uroniumsalze (15) erhält man auch durch Umsetzen von Isocyaniddichloriden (18) mit N-Chloraminen (5), Antimonpentachlorid und Alkoholen. Mit primären und sekundären Aminen setzen sich die Cyanamidiumsalze (2) zu tetra- bzw. pentasubstituierten Guanidinium-hexachloroantimonaten (16a-r) um.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19831160511
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  • 2
    Electronic Resource
    Electronic Resource
    Metal Complexes of Cyanamides and their Alkylation to Cyanamidium Salts. A General Synthesis of Highly Substituted Ureas, Isoureas, and Guanidines (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1161-1177 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Metallkomplexe von Cyanamiden und ihre Alkylierung zu Cyanamidiumsalzen. Eine allgemeine Synthese hochsubstituierter Harnstoffe, Isoharnstoffe und GuanidineAus disubstituierten Cyanamiden und Lewis-Säuren werden die Komplexe 3a - p erhalten. Nach einer Röntgenstrukturanalyse hat der Antimonpentachlorid-Komplex 3a weder s̰- noch π-Symmetrie ( ∡ C≡N - Sb 133°). Die Komplexe 3 mit SbCl5 oder FeCl3 können mit tertiären Alkylchloriden zu den kristallinen Cyanamidiumsalzen 5a - m alkyliert werden. Mit Wasser, primären oder sekundären Alkoholen reagieren die Verbindungen 5 zu Harnstoffen (11) bzw. Uroniumsalzen (8a - z), mit Ammoniak, primären oder sekundären Aminen zu Guanidiniumsalzen (9a - s).
    Notes: The complexes 3a - p were prepared from disubstituted cyanamides and Lewis acids. According to a X-ray structural analysis, the antimony pentachloride complex 3a is neither a s̰ nor a π complex (∡ C≡N - Sb 133°). The complexes 3 with SbCl5 and FeCl3 can be alkylated with tertiary alkyl chlorides, affording crystalline cyanamidium salts (5a - m) which were characterized by reactions with water, primary or secondary alcohols to give ureas (11) and uronium salts (8a - z), respectively. The guanidinium salts 9a - s were obtained with ammonia, primary and secondary amines.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19841170330
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  • 3
    Electronic Resource
    Electronic Resource
    Amino-substituted 2-Azaallenium Salts (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1900-1912 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Aminosubstituierte 2-AzaalleniumsalzeNitriliumsalze (14a - i) reagieren mit Iminen (15a - e) in guten Ausbeuten zu den mono- bis tetra-azasubstituierten 2-Azzalleniumsalzen 16a - w. Für die Verbindungen 16 wird eine Allengeometrie (A) oder alternativ eine planare 1,3-Diaza-1,3-butadienium-Struktur (B) diskutiert. Nach den IR-, 1H- und 13C-NMR-Spektren zu schließen, müssen die Salze 16 um das zentrale Stickstoffatom recht flexibel sein. Zumindest die Verbindungen 16a - d liegen in Lösung in einer chiralen Allenkonformation vor. Für die Rotationsbarrieren um die C=N+=C-Achse werden durch DNMR-Messungen Werte zwischen δG173† = 36 · 1 kJmol-1 für 16a und mehr als 90 kJmol-1 für 16c gefunden. Nach einer Röntgenstrukturanalyse liegt 16 o im Kristall in einer weitgehend idealen Allengeometrie (A) vor. - Es werden einige interessante 13C-14N-Kopplungen der Nitriliumsalze 14 beschrieben.
    Notes: Nitrilium salts (14a - i) react with imines (15a - e) to afford the mono- to tetraaza-substituted 2-azaallenium salts 16a - w in high yields. The stereochemistry of these compounds is discussed in terms of an allenic geometry (A) and a planar 1,3-diaza-1,3-butadienium structure (B), respectively. According to the IR, 1H and 13C NMR spectra, the azaallenium salts 16 are rather flexible around the central nitrogen atom. In solution at least 16a - d assume chiral conformations similar to those of allenes. By DNMR measurements barriers to hindered rotation around the C=N+=C axis were found to range from δG173† = 36 ± 1 kJmol-1 for 16a to more than 90 kJmol-1 for 16c. According to an X-ray structural analysis, 16o crystallizes in an almost perfect allene geometry (A). - Some interesting 13C-14N couplings of the nitrilium salts 14 are reported.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19841170518
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  • 4
    Electronic Resource
    Electronic Resource
    Preparation of 3,4,5-Trisubstituted 1,2,4-Oxadiazolium Salts from Nitrilium Salts (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 109-116 
    Details
    ISSN: 0009-2940
    Keywords: Nitrilium salts ; Nitrile oxides ; N-Hydroxycarboximidoyl chlorides ; 1,2,4-Oxadiazolium salts ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1,3-Cycloadditions of stable nitrile oxides 2 to nitrilium salts 1 afford high yields of 3,4,5-trisubstituted 1,2,4-oxadiazolium salts 3. N-Hydroxycarboximidoyl chlorides 4 add to nitrilium salts 1 to give isolable [(chloroalkylidene)aminooxyalkylidene]ammonium salts 5. A thermal stereomutation around the C = N+ bond is observed. On heating neat or in solution most compounds 5 cyclize to oxadiazolium salts 3. In cases where decomposition of 5 is faster than cyclization O-silylated N-hydroxycarboximidoyl chlorides 7 are treated with nitrilium salts 1 to furnish oxadiazolium salts 3.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19931260118
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