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  • 1985-1989
  • 1980-1984  (6)
  • 1965-1969  (7)
  • 1840-1849
  • 1830-1839
  • 1983  (6)
  • 1965  (7)
  • Alkenes
  • Heterocycles
Datenquelle
Materialart
Erscheinungszeitraum
  • 1985-1989
  • 1980-1984  (6)
  • 1965-1969  (7)
  • 1840-1849
  • 1830-1839
Jahr
Schlagwörter
  • 1
    Digitale Medien
    Digitale Medien
    Darstellung und Struktur von Pyrazolyl-Kationen mit Polymethin- und Methan-Gerüst (1983)
    Springer
    Monatshefte für Chemie 114 (1983), S. 219-225 
    Details
    ISSN: 1434-4475
    Schlagwort(e): Cyanine dyes ; Dipyrazolylmethanes ; Heterocycles ; N-15-NMR ; O-17-NMR ; Phenazon
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The 4-pyrazoline-3-one1 reacts with 4-dimethylaminobenzaldehyde to yield the stable asymmetric cyanine dye2b which reacts with1 to give the colorless (aryl) (dipyrazolyl) methane3b. Using aldehydes with less cationstabilizing groups the polymethines2 are not isolated but only the methanes3. The structures of2b and3 are discussed by1 H,13C and Hetero NMR spectra.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00798325
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  • 2
    Digitale Medien
    Digitale Medien
    Triazolo[4′,3′:4,5] [1,3,4]thiadiazolo[2,3-b]quinazolin-6-one (1983)
    Springer
    Monatshefte für Chemie 114 (1983), S. 339-342 
    Details
    ISSN: 1434-4475
    Schlagwort(e): Heterocycles ; Infrared ; 1H-NMR
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung 3-Methyl-6H-[1,2,4]triazolo[4′ ,3′ : 4,5] [1,3,4]thiadiazolo[2,3-b]chinazolin-6-on (6) wurde mittels Kondensation von Isatoesäureanhydrid (1) mit 4-Amino-5-mercapto-3-methyl[1,2,4]triazol (2) und anschließender Cyclisierung von Zwischenverbindung3 mit POCl3 und PCl3 dargestellt. Als Alternative konnte6 auch über die Kondensation von 3-Amino-2-mercapto-3H-chinazolin-4-on (7) mitN-Carbethoxyhydrazin in Gegenwart von HCl und anschließender Cyclisierung der Zwischenverbindung8 mit Essigsäure synthetisiert werden. Die Strukturen der Verbindungen wurden mittels IR,1H-NMR und Mikroanalyse nachgewiesen.
    Notizen: Abstract 3-Methyl-6H-[1,2,4]triazolo[4′,3′: 4,5] [1,3,4]thiadiazolo[2,3-b]quinazolin-6-one (6) has been synthesized by the condensation of isatoic anhydride (1) with 4-amino-5-mercapto-3-methyl-[1,2,4]triazole (2) and final cyclisation of the intermediate3 with POCl3 and PCl3. Alternatively6 could also be synthesized by the condensation of 3-amino-2-mercapto-3H-quinazolin-4-one (7) withN-carbethoxy hydrazine in presence of hydrochloric acid and final cyclisation of the intermediate8 with acetic acid. The structures have been confirmed on the basis of IR, PMR and analytical results.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00798956
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  • 3
    Digitale Medien
    Digitale Medien
    Bond-Forming Initiation in Spontaneous Addition and Polymerization Reactions of Alkenes (1983)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 22 (1983), S. 440-455 
    Details
    ISSN: 0570-0833
    Schlagwort(e): Initiation ; Addition ; Polymerization ; Alkenes ; C-C coupling ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Spontaneous addition and polymerization reactions of alkenes of different electron-densities result in a wide variety of small organic molecules and high polymers. Tetramethylenes are proposed as key intermediates, i.e. resonance hybrids of 1,4-diradical and zwitterionic limiting structures. Their character is determined by the substituents at the terminals: Zwitterionic character is favored by strong donors, such as alkoxy and dialkylamino groups, at the carbenium center and strong acceptor group such as diesters and cyano-esters, at the acceptor end, and aryl and vinyl groups as donors. Zwitterionic tetramethylenes initiate ionic homopolymerization, while diradical tetramethylenes initiate alternating copolymerization, thus providing an extremely sensitive technique for the detection and characterization of these intermediates. The effects of the donor and acceptor substituents can be arranged as an “Organic Chemist's Periodic Table”, wherein the areas of mechanistic change clearly emerge and which provides predictive capability. - This unifying concept of bondforming initiation is extended to spontaneous addition and polymerization reactions of heteroatom acceptor molecules and 7,7,8,8-tetrasubstituted quinodimethanes and of compounds possessing labile σ-bonds, such as halogens and peroxides. Radical-ion pairs, charge-transfer complexes and adventitious impurities are excluded as significant initiators.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/anie.198304401
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  • 4
    Digitale Medien
    Digitale Medien
    The Versatile Chemistry of 1,4-Diazines: Organic, Inorganic and Biochemical Aspects (1983)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 22 (1983), S. 171-190 
    Details
    ISSN: 0570-0833
    Schlagwort(e): 1,4-Diazines ; Pyrazine ; Heterocycles ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: In chemical research attention is increasingly being focussed on composite “complex” systems with special properties and functions. As components of such systems 1,4-diazines are steadily gaining in popularity. Here, 1,4-diazines means pyrazine and its derivatives as well as compounds with partial pyrazine structure; examples are quinoxaline, phenazine, pteridine, flavin and their derivatives. All these compounds are characterized by a low lying unoccupied π-molecular orbital and by the ability to act as bridging ligand. Due to these two properties 1,4-diazines, and especially their parent compound pyrazine, possess a characteristic reactivity. 1,4-Diazines may be employed to study inter- and intramolecular electron transfer in organic, inorganic and biochemical reactions. In the redox system of 1,4-diazines the paramagnetic 7π-electron intermediate exhibits exceptional stability, whereas the 1,4-dihydro-1,4-diazines with 8π-electrons in a six-membered ring are not generally accessible due to their potential antiaromaticity and their large excess of π electrons. Its inherent bifunctionality and the low lying unoccupied molecular orbital permit pyrazine to form coordination polymers having unusual electrical and magnetic properties. Finally, the phenomena observed for pyrazines may be used in the interpretation of the reactivity of naturally occurring 1,4-diazines, such as flavins and bioluminescent natural products.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/anie.198301713
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  • 5
    Digitale Medien
    Digitale Medien
    Formation of CC Bonds by Addition of Free Radicals to AlkenesDedicated to Professor Karl Winnacker on the occassion of his 80th birthday (1983)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 22 (1983), S. 753-764 
    Details
    ISSN: 0570-0833
    Schlagwort(e): Addition ; Free radicals ; Alkenes ; C-C coupling ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: There are many reactions in which CC bonds are formed by addition of free radicals to alkenes. Information about the mechanism is important for the synthesis of specific target molecules. The rate of addition of alkyl radicals to alkenes is controlled by steric and polar effects. The stabilities of the educts and products are of only limited importance, since the transition states for these exothermic reactions occur very early on the reaction coordinate. Variations in reactivity and selectivity can be described using frontier orbital theory: for nucleophilic radicals the dominant interactions are those between SOMO's and LUMO's, and for electrophilic radicals those between SOMO's and HOMO's. The large differences in the steric effects of α - and β- substituents of alkenes can be explained by postulating an unsymmetrical transition state -  the radical approaches one of the C atoms preferentially. Regioand stereoselectivities can be predicted and are determined, in general, by steric effects.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/anie.198307531
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  • 6
    Digitale Medien
    Digitale Medien
    Homolytic Cyclizations of N-ChloroalkenylaminesDedicated to Professor Jean-Marie Surzur on the occasion of his 50th birthday. (1983)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 22 (1983), S. 337-350 
    Details
    ISSN: 0570-0833
    Schlagwort(e): Cyclization ; Chloroamines ; Alkenylamines ; Synthetic methods ; Heterocycles ; Free radicals ; Natural products ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Many N-chloroalkylamines with double bond(s) dissociate homolytically to give chlorine atoms and aminyl radicals which undergo intramolecular cyclization reactions. Here, the nature of the aminyl radicals (neutral, protonated, or complexed to metal salts) appears to be important. The reactivity varies strongly from one species to another, and their selectivities can be different towards addition, substitution, abstraction, or dimerization reactions. A good synthetic tool appears to be the “complexed radical”, which is generated under mild conditions. A variety of β-functionalized, substituted, fused, or bridged azaheterocycles with alkaloid part structures thus become easily accessible in high yields, in a regio- and, possibly, stereoselective manner. Many examples are discussed illustrating the synthetic possibilities, limitations, and mechanistic features of this cyclization process.
    Zusätzliches Material: 7 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/anie.198303373
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  • 7
    Digitale Medien
    Digitale Medien
    Eliminations from Olefins (1965)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 4 (1965), S. 49-68 
    Details
    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
    URL: http://dx.doi.org/10.1002/anie.196500491
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  • 8
    Digitale Medien
    Digitale Medien
    New Reactions of Alkylidenephosphoranes and their Preparative Uses. Part I: The Acid-Base Character of Phosphonium Salts and AlkylidenephosphoranesParts II and III will appear shortly in this journal. (1965)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 4 (1965), S. 583-587 
    Details
    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
    URL: http://dx.doi.org/10.1002/anie.196505831
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  • 9
    Digitale Medien
    Digitale Medien
    New Reactions of Alkylidenephosphoranes and their Preparative Uses. Part II. Alkylidenephosphoranes and Halogen CompoundsFor Part I see Angew. Chem. 77,609 (1965), Angew. Chem. internat. Edit. 4, 583 (1965). Part III will appear shortly in this journal. (1965)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 4 (1965), S. 645-660 
    Details
    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
    URL: http://dx.doi.org/10.1002/anie.196506451
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  • 10
    Digitale Medien
    Digitale Medien
    The Hetarynes (1965)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 4 (1965), S. 543-557 
    Details
    ISSN: 0570-0833
    Schlagwort(e): Hetarynes ; Heterocycles ; Alkynes ; Arynes ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Investigations carried out during the last six years have shown that, as in the case of benzene, an extra bond can be introduced into heteroaromatic rings. Since this possibility does not appear to be confined to exceptional cases, the heterocyclic arynes (hetarynes) promise a much wider variety than the carbocyclic arynes. Hetarynes occur mainly as intermediates in nucleophilic substitutions on halogenated heterocyclic compounds. Since the replacement of a CH group in dehydrobenzene by a nitrogen atom and the condensation of benzene rings have stabilizing effects, the stability of hetarynes is expected to increase with the number of N atoms and with the number of condensed aromatic rings.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/anie.196505431
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  • 11
    Digitale Medien
    Digitale Medien
    New Reactions of Alkylidenephosphoranes and their Preparative Uses IIIFor Part I, see Angew. Chem. 77, 609 (1965) Angew. Chem. internat. Edit. 4, 583 (1965); for Part II, see Angew. Chem. 77, 651 (1965); Angew. Chem. internat. Edit. 4, 645 (1965).. Alkylidenephosphoranes and Reagents Containing Multiple Bonds (1965)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 4 (1965), S. 830-838 
    Details
    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
    URL: http://dx.doi.org/10.1002/anie.196508301
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  • 12
    Digitale Medien
    Digitale Medien
    New Methods in the Chemistry PyridazonesPublished on the occasion of the 100th anniversary of the establishment of Badische Anilin- & Soda-Fabrik AG., on April 6th, 1965. (1965)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 4 (1965), S. 292-300 
    Details
    ISSN: 0570-0833
    Schlagwort(e): Pyridazones ; Heterocycles ; Mucochloric acid ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A new synthesis of mucochloric acid by chlorination of butynediol has facilitated the preparation of a series of 4,5-dichoropyridazones. The high reactivity of these compounds has been investigated and applied in several ways. New classes of compounds, some with biological activity, were obtained by displacement of the chlorine atoms. New heterocyclic systems were prepared by condensation and rearrangement reactions.
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/anie.196502921
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  • 13
    Digitale Medien
    Digitale Medien
    Heterocycles Containing Phosphorus (1965)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 4 (1965), S. 1023-1038 
    Details
    ISSN: 0570-0833
    Schlagwort(e): Heterocycles ; Phosphorus ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The preparation of heterocycles containing phosphorus is described. The chemical behavior of ring systems containing trivalent phosphorus is mainly determined by their phosphine character; heterocyclic behavior in the ordinary sense is shown by rings containing functional groups. Syntheses and reactions of cyclic compounds of pentavalent and hexavalent phosphorus are particularly interesting.
    Zusätzliches Material: 3 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/anie.196510231
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