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  • 1
    Electronic Resource
    Electronic Resource
    Lithiierung und elektrophile Substitution an α-Methylengruppen von Nitrosaminen Umpolung der Reaktivität sekundärer Amine (1977)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1852-1865 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Lithiation and Electrophilic Substitution at α-Methylene Groups of Nitrosamines Reactivity Umpolung of Secondary Amines1,2)The electrophilic substitution at the α-position of nitrogen of secondary amines (A → B) has a broad scope. H/Li-exchange can be carried out with lithium diisopropylamide (LDA) at -78°C in THF at methylene groups of open chain (1) and cyclic (9-12) nitrosamines. The resulting lithio derivatives react in high yields with alkyl, allyl, and benzyl halides as well as with aldehydes and ketones to give products 3 and 13-16 under C—C-bond formation. The reaction is also used for cyclizations (°11, 18—20). Most of the nitrosamines prepared are denitrosated to the parent amines.
    Notes: Die elektrophile Substitution in α-Stellung zum Stickstoff sek. Amine (A → B) über metallierte Nitrosamine besitzt große Anwendungsbreite. Der H/Li-Austausch gelingt bei - 78°C in THF an Methylengruppen von offenkettigen (1) und cyclischen (9-12) Nitrosaminen mit Lithium-diisopropylamid (LDA). Umsetzung der Li-Derivate mit Alkyl-, Allyl- und Benzylhalogeniden sowie mit Aldehyden und Ketonen führt in hohen Ausbeuten unter C—C-Verknüpfung zu den Produkten 3 und 13—16. Die Reaktion wird auch für Cyclisierungen zu 11 und 18-20 eingesetzt. Die meisten der hergestellten Nitrosamine werden zu den freien Aminen entnitrosiert.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19771100529
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  • 2
    Electronic Resource
    Electronic Resource
    Regio- und stereochemischer Verlauf der Reaktionen von substituierten 2-Lithio-N-nitrosopiperidinen (1977)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1866-1878 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Regio- and Stereochemical Course of the Reactions of Substituted 2-Lithio-N-nitrosopiperidinesIt is demonstrated that lithiation and reactions of substituted nitrosopiperidines 1a-7a with electrophiles (D2O, alkyl halides, carbonyl compounds) leads to the formation of 1c, d, 2c, d, 3c, 4c, d, 5c, 6c, d, and 7c,d in a regio- and stereoselective manner. 1H- and 13C n.m.r. analysis allows assignment of the structures and/or configurations which  -  in the case of the benzophenone adducts 1d, 2d, and 4d  - is not in accord with previous models of product control in nitrosamine anion reactions.
    Notes: Am Beispiel der substituierten Nitrosopiperidine 1a-7a wird gezeigt, daß Lithiierung und Umsetzung mit Elektrophilen (D2O, Alkylhalogenide; Carbonylverbindungen) regio- und stereoselektiv zu den Produkten 1c, d, 2c, d, 3c, 4c, d, 5c, 6c, d und 7c, d führt. 1H- und 13C-NMR-Analyse liefern Zuordnungen von Konstitutionen und/oder Konfigurationen, die bei den Benzophenonaddukten 1d, 2d und 4d nicht mit den bisherigen Vorstellungen über die Produktsteuerung bei Nitrosamin-Anionreaktionen übereinstimmen.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19771100530
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  • 3
    Electronic Resource
    Electronic Resource
    Reaktionen von 1-Nitrosamino-allyllithiumverbindungen. Reversibilität der Carbonyladdition (1977)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 2334-2354 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of 1-Nitrosamino-allyllithium Compounds. Reversibility of the Carbonyl AdditionThe reaction of lithiated allyl-tert-butyl- (2) and -methylnitrosamine (14) with alkylating and hydroxyalkylating reagents is investigated. Both show kinetically favoured α-reactivity. The irreversible alkylations lead exclusively to α-products 4 and 15aα, respectively. The tert-butyl derivative 2 adds to aldehydes and ketones to give α- and γ-products 7α und 7γ, the ratio of which depends upon the nature of the carbonyl compound employed and the conditions used. It is proved, that the additions of 2 to benzaldehyde and cyclohexanone are reversible: if the reactions are carried out under thermodynamic conditions the γ-isomers 7cγ (see 11 → 12) and 7dγ are formed exclusively. In the case of the methyl derivative 14 the reversibility of the carbonyl addition reactions is demonstrated by the α/γ isomerization of the benzophenone adduct (15dα → 15dγ) and by the equilibration of the two diastereomers 15cα. Thus the thermodynamic stabilities of the primary Li alkoxide adducts control product formation. The potassium derivatives of 1 and 13 yield the same products with benzaldehyde and benzophenone as the corresponding Li derivatives 2 and 14. The general importance of the reversibility of carbonyl additions is discussed.
    Notes: Lithiiertes Allyl-tert-butyl- (2) und -methylnitrosamin (14) werden mit Alkylierungsmitteln, Aldehyden und Ketonen umgesetzt. Beide zeigen kinetisch bevorzugte α-Reaktivität: die irreversiblen Alkylierungen führen nur zu α-Produkten 4 bzw. 15a α. Das tert-Butylderivat 2 reagiert mit Aldehyden und Ketonen zu α- und γ-Produkten 7α und 7γ, deren Mengenverhältnis von der Art der Carbonylverbindung und den Reaktionsbedingungen abhängt. Es wird bewiesen, daß die Addition von 2 an Benzaldehyd und Cyclohexanon reversibel ist, was bei thermodynamischer Versuchsführung zur ausschließlichen Bildung der γ-Isomeren 7cγ (siehe 11 → 12) und 7d γ führt. Im Falle des Methylderivates 14 wird die Reversibilität der Carbonyladdition durch α/γ-Isomerisierung des Benzophenonadduktes (15dα → 15dγ) und durch die Äquilibrierung der beiden Diastereomeren von 15c α bewiesen. Die thermodynamische Stabilität der Primäraddukt-Li-Alkoholate steuert also letztlich die Produktbildung. Aus K-Derivaten von 1 und 13 entstehen mit Benzaldehyd und Benzophenon dieselben Produkte wie bei Verwendung der Li-Verbindungen 2 und 14. Die allgemeine Bedeutung der Reversibilität von Carbonyl-additionsreaktionen wird diskutiert.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19771100630
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  • 4
    Electronic Resource
    Electronic Resource
    Drei neue Varianten der C—C-Verknüpfung mit Nitrosaminen (Erzeugung und Herstellung sowie Umsetzungen von Kalium- und Zinn-Derivaten; Acylierung mit α-Ketonitrilen) (1978)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 111 (1978), S. 2630-2645 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Three New Modifications of C—C-Bond Formation with Nitrosamines (Generation and Preparation as well as Reactions of Potassium and Tin Derivatives; Acylations with α-Ketonitriles)Metalation of nitrosamines with potassium tert-butoxide/butyllithium/diisopropylamine (KDA) takes place more rapidly than with lithium diisopropylamide (LDA) and leads to the more reactive potassium derivatives (see table 1). The use of potassium tert-butoxide alone for C—C-bond formation between nitrosamines and carbonyl compounds in situ is feasible only with non-enolizable aromatic aldehydes and diarylketones; the addition under these conditions is reversible, the position of the equilibrium depends strongly upon steric factors (see table 2 and scheme 1). α-Stannylated nitrosamines 21, 22 add thermally to benzaldehydes and cinnamaldehyde to give stannylethers of the alcohols 24-26 which are readily cleaved with aqueous acid. The poor yields of acylated nitrosamines obtained from the lithio derivatives with carboxylic acid esters, -chlorides, or -anhydrides can be greatly improved by employing acyl cyanides (products 28-30 and table 5).
    Notes: Die Metallierung von Nitrosaminen mit Kalium-tert-butylat/Butyllithium/Diisopropylamin (KDA) ist schneller als mit Lithium-diisopropylamid (LDA) und führt zu den reaktiveren Kaliumderivaten (s. Tab. 1). Die C—C-Verknüpfung zwischen Nitrosaminen und Carbonylverbindungen mit Kalium-tert-butylat allein gelingt wegen der Reversibilität der Reaktion nur mit nicht enolisierbaren, aromatischen Aldehyden und Diarylketonen und spricht empfindlich auf sterische Behinderung an (s. Tab. 2 und Schema 1). Die α-stannylierten Nitrosamine 21, 22 addieren rein thermisch an Benzaldehyde und Zimtaldehyd zu den leicht spaltbaren Stannylethern der Alkohole 24-26. Acylierungen von Li-Nitrosaminen, die mit Carbonsäureestern, -chloriden und -anhydriden bevorzugt zu Diaddukten D (z. B. 19) führen, sind mit Acylcyaniden in besseren Ausbeuten möglich (Produkte 28-30 und Tab. 5).
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19781110718
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  • 5
    Electronic Resource
    Electronic Resource
    1, 4, 5, 6-Tetrahydro-ν-tetrazin-DerivateZum Teil vorläufig mitgeteilt [1] [2].Diese Arbeit enthält die wesentlichen Ergebnisse der Dissertation von R.D., Universität Giessen, 1977. (1978)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 61 (1978), S. 1622-1647 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1, 4, 5, 6-Tetrahydro-ν-tetrazin-DerivateThe title compounds 2 and 13 are readily available from α-lithiated N-alkyl-nitrosoamines 1 (see Tables 1 and 2) which decompose at - 73° to yield the N-oxides 2. The ESR. spectra of two derivatives 1 are recorded (Fig. 1), and tentative mechanisms are proposed for the head to head dimerizations (la- 3- 4- 5- 2a and Scheme 1). Coupling of lithionitrosoamines with iodine (-6) and alternative decomposition routes of representatives of this class of organometallics with special substitution [equations (2)-(5)] are reported.The structures of the tetrazines are established by spectroscopic data [ESCA] (Fig. 2), IR., UV., 1H- (cf. Fig. 9) and 13C-NMR., PE. (Scheme 2), by an X-ray analysis of 2a (Fig. 4-8 and Table 3), and by the chemical reactions. The crystal structure of 2a is a twisted boat with non planar terminal nitrogen atoms which reflects the electron repulsion in the 4-atom-6-electron N—N=N≡N-system. Comparisons are made with 2-tetrazenes, the open chain analogues of 13, wherever possible. Raney-Ni reductions of 2 or 13 gives diamines 14 to which is assigned the d, l-configuration through the 1H-NMR. spectra of the aminals 7 and 15. Neither the oxides 2 nor the tetrazines 13 undergo cycloaddition reactions [equation (6) and Section 4].Compound 2a is dimerized to the bis (nitrosoamino)-2-tetrazene 18 by treatment with acid, ZnII, CuI or iodomethane. 2a is oxidized at nitrogen to the ethylene diamine derivative 6a (through 20, with H2O2), or at the CH2-groups of the ring to give oxo-N-oxide 21 (with MnO2 or the ring contracted oxo-tetrazoline-N-oxide 22 (with KMnO4).Pyrolysis or photolysis of the dimethyl tetrahydrotetrazine 13a furnishes the trimer 26 of N-methylimine, but no diazetidine 27. Silver and mercury complexes 29 are obtained from 13a, while Cr(CO)5. THF does not furnish a complex as with azocompounds, but rather replaces N2 in 13a by CO (→ 28). Oxidation with permanganate converts 13a into the oxalic acid derivative 30 with unchanged tetrazine structure.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19780610512
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  • 6
    Electronic Resource
    Electronic Resource
    Synthese und Bestimmung der absoluten Konfiguration von Pyrenophorin und VermiculinTeil der geplanten Dissertation von B. Seuring. Universität Gießen. Diese Arbeit wurde von der Deutschen Forschungsgemeinschaft und dem Fonds der Chemischen Industrie unterstützt. Wir danken Dr. H. Gerlach (ETH Zürich) und Dr. J. Fuska (Universität Bratislava) für Vergleichsproben. (1977)
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 89 (1977), S. 270-271 
    Details
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ange.19770890427
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  • 7
    Electronic Resource
    Electronic Resource
    Die magnetische Nichtäquivalenz der C-Atome prochiraler Diphenylmethylgruppen in der 13C-NMR-Spektroskopie (1976)
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 88 (1976), S. 256-257 
    Details
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ange.19760880808
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  • 8
    Electronic Resource
    Electronic Resource
    2-(2-Amino-2-methylpropyl)phenole durch C — C-Verknüpfung von 2-Hydroxybenzylalkoholen mit 2-NitropropananionenHerrn Prof. Dr. Rolf Sammet zu seinem 60. Geburtstag gewidmet. (1980)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1980 (1980), S. 1239-1251 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 2-(2-Amino-2-methylpropyl)phenols by C - C-Linkage of 2-Hydroxybenzyl Alcohols with 2-Nitropropane AnionsHerrn Prof. Dr. Rolf Sammet zu seinem 60. Geburtstag gewidmet.The 2-hydroxybenzyl alcohols 1, 6, 8a and 8e can be converted into the 2-(2-methyl-2-nitropropyl)-phenols 2, 7, and 9 by a SRN1-reaction with the sodium salt of 2-nitropropane. Catalytic hydrogenation yields the amines 3 and 10. The consequent reactions  -  leading to the quaternary salts 13 and 14 and as to the addition-compounds 15 and 16  -  are negatively influenced by the strong steric shielding of the amino groups.
    Notes: Die 2-Hydroxybenzylalkohole 1, 6, 8a und 8e lassen sich in einer SRN1-Reaktion mit dem Natriumsalz des 2-Nitropropans zu den 2-(2-Methyl-2-nitropropyl)phenolen 2, 7 und 9 kondensieren. Katalytische Hydrierung liefert die Amine 3 und 10, deren Folgereaktionen zu den quatären Salzen 13 und 14 sowie den Additionsprodukten 15 und 16 durch die starke sterische Abschirmung der Aminofunktion negativ beeinflußt werden.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198019800808
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  • 9
    Electronic Resource
    Electronic Resource
    Magnetic Nonequivalence of the C Atoms of Prochiral Diphenylmethyl Groups in 13C-NMR Spectroscopy (1976)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 15 (1976), S. 234-235 
    Details
    ISSN: 0570-0833
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/anie.197602342
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  • 10
    Electronic Resource
    Electronic Resource
    Synthesis and Determination of the Absolute Configuration of Pyrenophorin and VermiculinPart of the planned dissertation by B. Seuring, Universität Giessen. This work was supported by the Deutsche Forschungsgemeinschaft and the Fonds der Chemischen Industrie. We thank Dr. H. Gerlach (ETH Zürich) and Dr. J. Fuska (University of Bratislava) for samples. (1977)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 16 (1977), S. 264-265 
    Details
    ISSN: 0570-0833
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/anie.197702641
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