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  • Artikel: DFG Deutsche Nationallizenzen  (10)
  • 1990-1994
  • 1965-1969  (10)
  • 1920-1924
  • 1840-1849
  • 1830-1839
  • 1966  (2)
  • 1965  (8)
  • Alkenes  (5)
  • Phosphonium salts  (4)
  • Polymers  (4)
Datenquelle
  • Artikel: DFG Deutsche Nationallizenzen  (10)
Materialart
Erscheinungszeitraum
  • 1990-1994
  • 1965-1969  (10)
  • 1920-1924
  • 1840-1849
  • 1830-1839
Jahr
  • 1
    ISSN: 0570-0833
    Schlagwort(e): Allyl transition metal systems ; Bis(allyl)nickel ; Nickel ; Polymerization ; Alkenes ; Allylic ligands ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: As a continuation of a report published in 1963, recent results in the field of allyl-transition metal complexes are describedThe term “allyl compounds” in the present paper refers not only to compounds containing the simple allyl group (CH2=CH—CH2—), but also to those that contain substituted allyl groups or allyl groups forming part of a ring system.. Syntheses and reactions of these compounds, as well as the bonding between metal and allyl group, are discussed. Allyl-transition metal complexes form the basis of extremely selective catalysts for homogeneous reactions of 1, 3-diolefins and of olefins; the metal atoms in these “matrix” catalysts are either “bare”The description “bare” is applied to complexed metal atoms from which the ligands can be quantitatively displaced by the substances taking part in catalytic reactions. or are bound to only a few ligands.
    Zusätzliches Material: 3 Tab.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 5 (1966), S. 862-870 
    ISSN: 0570-0833
    Schlagwort(e): Polymers ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The difficulties encountered in the preparation of polymers that are uniform chemically, structurally, and in their molecular weight are due mainly to the wide variety of possible polymers. This arcticle gives a review of attempts to synthesize homogeneous polymers by chain reactions and by stepwise synthesis. Syntheses on templates are extremely important in living cells; methods have recently been found for syntheses of this type that are independent of natural processes. Uniform polymers can also be obtained by reactions on existing polymers. In replicating polymers, this in principle requires the modification of only one polymer molecule.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 4 (1965), S. 49-68 
    ISSN: 0570-0833
    Schlagwort(e): Elimination ; Alkenes ; Alkynes ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Eliminations from olefins are very often initiated by bases, and usually lead to formation of acetylene derivatives. In view of the numerous side-reactions and subsequent additions or rearrangments observed, the nature of the base used is of considerable significance. Organometallic bases are very versatile. In addition to dehydrohalogenation, dehalogenation by metals, and also thermolytic and photolytic eliminations. (e.g. the retrodiene reaction with exchange of substituents) are discussed. Elimination from low-membered cyclic olefins yields cycloalkynes having strained ring-systems, and the existence of these can be demonstrated by trapping them. The mechanisms known for β-elimination (E2, E1 and E1cB) occur also in the case of olefins; however - due to the sp2-hybridization of the carbon atoms taking part - they are realized with different rates of reaction relative to saturated compounds. α-Eliminations from olefines having aryl residues in the β-position lead to formation of arylacetylenes by rearrangement of the carbon skeleton. The mechanism of this reaction, which is known as the Fritsch-Buttenberg-Wiechell rearrangement, is discussed in considerable detail, and several variations of the reaction are considered. According to present-day knowledge carbenes are involved in α-eliminations only when both β-positions of the olefin are occupied by aliphatic substituents, or when they are occupied by aromatic residues where rearrangement to acetylenes is impossible for steric reasons (as for example with 9-chloromethylenefluorene). With organolithium compounds a number of dehydrohalogenations, which are formally β-eliminations, actually proceed via deprotonation on the halogenbearing carbon atom (α-metallation). α-Metallations are the rate-determining steps when ether is used as solvent, but proceed quickly in tetrahydrofuran even at low temperatures. Compounds of the type \documentclass{article}\usepackage{amssymb}\pagestyle{empty}\begin{document}$\raise1pt\hbox{$〉$}{\rm C}\raise1pt\hbox{=\kern-3.45pt=}{\rm C(Li)Cl}$\end{document} may be prepared by this method and are recognized as intermediates in α-eliminations.
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 4 (1965), S. 394-401 
    ISSN: 0570-0833
    Schlagwort(e): Copolymers ; Polymers ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Various chemical procedures are available for studying the sequence distribution in copolymers, but none can be applied routinely. The run-number approach permits the results of such studies to be treated with ease; all results obtained to date are consistent with classical copolymerization theory.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 4 (1965), S. 1051-1060 
    ISSN: 0570-0833
    Schlagwort(e): Copolymers ; Polymers ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The physical properties of copolymers are determined by their compostions and by the distribution of monomeric sequences in their chains. In some cases, sequence distributions can be determined from or correlated with physical properties observed for copolymers. Such determinations or correlations are relatively simple when calculations are based on run numbers.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 6
    ISSN: 0570-0833
    Schlagwort(e): Phosphonium salts ; Vitamins ; Wittig reactions ; Carbonyl olefination ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: For syntheses in the carotenoid field using the Wittig reaction, particularly on the technical scale, it was necessary to carry out extensive studies on the preparation and properties of the intermediates. Hear the part of this work is discussed which dealt with quaternary phosphonium compounds of trimethylcyclohexene derivatives.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 7
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 4 (1965), S. 583-587 
    ISSN: 0570-0833
    Schlagwort(e): Alkylidenephosphoranes ; Phosphonium salts ; Synthetic methods ; Phosphoranes ; Ylides ; Alkenes ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Phosphonium salts may be regarded as Bronsted acids, and alkylidenephosphoranes as the conjugate bases. Compounds of the two classes exist in equilibrium with each other. Phosphonium salts and alkylidenephosphoranes can be obtained by this “transylidation”. Other methods are also given for the preparation of members of both classes.
    Materialart: Digitale Medien
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  • 8
    ISSN: 0570-0833
    Schlagwort(e): Alkylidenephosphoranes ; Phosphonium salts ; Synthetic methods ; Phosphoranes ; Ylides ; Alkenes ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The reaction of alkylidenephosphoranes with compounds containing halogens can be used to prepare ylides, which can be converted in to useful products, e.g. by hydrolysis, by thermal decomposition, or by other reactions. Examples of such products are ketones including cyclic, unsaturated, and branched-chain ketones (including cyclic, unsaturated, and branched-chain ketones), carboxlic esters (including those of unsaturated, branched- chain, polyenecarboxylic, acetylenecarboxylic, and allenecarboxylic acids), and aldehydes.
    Zusätzliches Material: 10 Tab.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 9
    ISSN: 0570-0833
    Schlagwort(e): Alkylidenephosphoranes ; Phosphonium salts ; Synthetic methods ; Phosphoranes ; Ylides ; Alkenes ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A few examples of preparatively useful syntheses using alkylidenephosphoranes and substances containing a C—N or C—C double bond are the preparations of olefins, allenes, pyran derivatives, and cyclopropane derivatives. Olefins, ketones, and monocyclic compounds can be obtained by autoxidation of alkylidenephosphoranes; α, β-dioxo compounds (including cyclicones) can be prepared by oxidation with peroxy-acids. Alkylidenephosphoranes can also be used for the synthesis of azines and Schiff bases. Of the many possibilities offered by the Wittig reaction, only the preparation of tritiated aldehydes and olefins will be considered.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 10
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 4 (1965), S. 107-112 
    ISSN: 0570-0833
    Schlagwort(e): Configuration ; Polymers ; Tacticity ; Stereochemistry ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: It is possible to draw analogies between linear polymers and cyclic compounds. Stereochemical considerations developed in this connection led to the recognition of new aspects of importance for the systematic classification of both classes of compounds; for example, asymmetric structures can be predicted which had hitherto never been suspected. - The concept of “diasteric centers” is introduced, and the definition of an “asymmetric center” is expressed in more general terms.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
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