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  • 1980-1984  (11)
  • Inorganic Chemistry  (9)
  • 41  (1)
  • Amoeba proteus  (1)
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  • 1
    Electronic Resource
    Electronic Resource
    A new model for the explanation of the saturation buildup in the transverse HGMS-configuration (1983)
    Springer
    Applied physics 32 (1983), S. 79-85 
    Details
    ISSN: 1432-0630
    Keywords: 85.70 ; 41
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract A model for the description of saturation buildup curves on single-capture elements is presented. It avoids the principal difficulties connected with the so-called SEB model in the case of the transverse HGMS-geometry. The basic idea of this model consists of the “linking” of the normal and tangential components of the forces acting at the buildup surface by a force of static friction. In contrast to the SEB-model the fact that the saturation buildup surface is neither circular nor concentric with the cross section of the capture element is taken into account. After evaluating two sets of experimental data and calculating the coefficient of static frictionf the “model of static friction” is submitted to a first examination. Within the accuracy of these preliminary measurements and even with an approximate evaluation of the fluid drag force the usefulness of the proposed method is established.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00617832
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  • 2
    Electronic Resource
    Electronic Resource
    Dynamics of the cytoskeleton inAmoeba proteus: II. Influence of different agents on the spatial organization of microinjected fluorescein-labeled actin (1984)
    Springer
    Protoplasma 119 (1984), S. 79-92 
    Details
    ISSN: 1615-6102
    Keywords: Amoeba proteus ; Cytoskeleton ; Morphological changes ; Iodoacetamido-fluorescein-(IAF)-labeled actin ; Microinjection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Iodoacetamido-fluorescein-(IAF)-labeled actin was microinjected into normal locomotingAmoeba proteus. Thereafter (30–60 minutes) changes in the cytoplasmic fluorescence distribution pattern and contractile activity were induced by internal and external chemical stimulation. Different agents such as phalloidin, procaine, 2.4-dinitrophenol (DNP), puromycin, ouabain and n-ethyl maleimide (NEM) interfere with the excitation-contraction mechanism involved in ordered pseudopodium formation during ameboid movement and cause various morphogenetic reactions based on actin polymerization-depolymerization cycles. Most frequent changes are (a) local condensation of IAF-actin and formation of a continuous IAF-actin layer at the cytoplasmic surface of the cell membrane and around the pulsating vacuole, (b) immobilization and hyalo-granuloplasm separation by combined contraction and detachment of the IAF-actin layer from the cell membrane, (c) organized and disorganized formation of pseudopodia by local contraction and disintegration of the IAF-actin layer, and (d) alterations in the rheological properties of the protoplasmic matrix by changes in the molecular state of soluble actin not incorporated into the cytoskeleton. The experimental approaches to the function of the actomyosin system in large amebas attainable by the method ofin vivo molecular cytochemistry are discussed in detail with respect to the participation of the cytoskeleton in motive force generation for cytoplasmic streaming and ameboid movement.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01287820
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  • 3
    Electronic Resource
    Electronic Resource
    Synthesis of α,β-Unsaturated and Other Reactive Acyl Cyanides (1982)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 115 (1982), S. 3880-3885 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesen von α,β-ungesättigten und anderen reaktiven AcylcyanidenReaktive aliphatische Acylcyanide (1-10, siehe Tab. 1) werden aus Acylchloriden, Natriumiodid und Kupfer(I)-cyanid unter verschiedenen Bedingungen dargestellt. Die Reaktion verläuft über die Acyliodide.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19821151219
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  • 4
    Electronic Resource
    Electronic Resource
    2,2,4,4-Tetramethyl-3-methylenebicyclo[3.2.1]oct-6-ene (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 3325-3329 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 2,2,4,4-Tetramethyl-3-methylenbicyclo[3.2.1]oct-6-enDie sterisch anspruchsvolle Titelverbindung 1 wurde in einer Eintopfreaktion aus Cyclopentadien und 2,4-Dimethyl-3-[(trimethylsilyl)methyl]-3-penten-2-ol (5) in Gegenwart von Titantetrachlorid/N-Methylanilin hergestellt. 2,2,4,4-Tetramethylbicyclo[3.2.1]oct-6-en-3-on (4) wurde vereinfacht im 15-g-Maßstab dargestellt.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19841171117
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  • 5
    Electronic Resource
    Electronic Resource
    A new approach to dehydrocamphenilone and camphenilone (1982)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 115 (1982), S. 1256-1258 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Eine neue Darstellung von Dehydrocamphenilon und CamphenilonBenzilsäureumlagerung von Dehydrocarbocamphenilon (4) ergibt die α-Hydroxysäure 5, welche mit Bleitetraacetat oxidativ zu Dehydrocamphenilon (2) decarboxyliert wird. Die gleiche Reaktionsfolge führt von Carbocamphenilon (9) zu Camphenilon (3).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19821150342
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  • 6
    Electronic Resource
    Electronic Resource
    Notizen. The Synthesis of Iodoglyoxalic Esters. Cleavage of Tetrahydrofuran and 1,2-Dimethoxyethane (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 408-412 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die Synthese von Iodglyoxylsäureestern. Spaltung von Tetrahydrofuran und 1,2-DimethoxyethanEine Serie von Iodglyoxylaten 2a - i wird aus Chlorglyoxylaten 1a - i und Natriumiodid in Acetonitril dargestellt und durch Tieftemperaturextraktion mit Pentan isoliert. Iodglyoxylsäureester eignen sich zur acylierenden Spaltung von Ethern, z. B. Tetrahydrofuran und 1,2-Dimethoxyethan.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19841170132
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  • 7
    Electronic Resource
    Electronic Resource
    Cycloadditions of Allyl Cations, 29. Acid Catalyzed Reactions of 2,3-Dimethyl-3-penten-2-ol and Cyclopentadiene in Two Phases. Formation of Seven- and Five-membered Rings (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 2898-2906 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cycloadditionen von allyl-Kationen, 29. Säurekatalysierte Reaktionen von 2,3-Dimethyl-3-penten-2-ol mit Cyclopentadien in zwei Phasen. Bildung von sieben- und fünfgliedrigen Ringen2,3-Dimethyl-3-penten-2-ol (3) und Cyclopentadien wurden in verdünnter wäßriger Sulfonsäure/Pentan Gerührt. Es bildeten sich 2,3,4,4-Tetramethylbicyclo[3.2.1]octa-2,6-dien (4), die epimeren 3-Methylen-Isomeren 5a, b und zum ersten Mal auch ein fünfgliedriger Ring, nämlich 2,3,4,4-Tetramethylbicyclo[3.3.0]octa-2,6-dien (6) mit 69 - 73% Gesamtausbeute. Das bicyclische Dien 4 war Hauptprodukt und wurde leicht als kristallisierter Silbernitratkomplex (C12H18)2·AgNO3 isoliert (41-44%). In einem modifizierten Verfahren wurde die Zweiphasenreaktion bei 0°C ausgeführt. Anschließend wurden die resultierenden Alkohole chromatographisch abgetrennt und bei 50°C cyclisiert. Diese Variante ergab einen höheren Anteil des thermodynamisch stabileren, neuartigen [3.3.0]-Bicyclus 6 (4:6 = 2.6:1).
    Notes: 2,3-Dimethyl-3-penten-2-ol (3) and cyclopentadiene were stirred in dilute aqueous sulfonic acid/pentane, giving 2,3,4,4-tetramethylbicyclo[3.2.1]octa-2,6-diene (4), the epimeric 3-methyl-ene isomers 5a, b and, for the first time, also a five-membered ring, namely 2,3,4,4-tetramethylbicyclo[3.3.0]octa-2,6-diene (6) in 69 - 73% overall yield. The major bicyclic diene 4 was conveniently isolated as crystalline silver nitrate complex (C12H18)2·AgNO3 (41 - 44%). In a modified approach the two phase reaction was carried out at 0°C, the resulting alcohols were separated by chromatography and cyclized at 50°C, giving an increased proportion of the thermodynamically more stable, novel [3.3.0] bicyclic isomer 6 (4:6 = 2.6:1)
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140820
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  • 8
    Electronic Resource
    Electronic Resource
    Cycloadditions of allyl cations, 22. Allyl alcohols as precursors of allyl cations (1980)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 3837-3847 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cycloadditionen von Allyl-Kationen, 22. Allylalkohole als Vorläufer für Allyl-KationenAllylalkohole wie 3-Ethoxy-2-methyl-3-buten-2-ol (4), der silylierte Alkohol 8 sowie 2-Methyl-3-pentin-2-ol (12) werden in die entsprechenden Trifluoressigsäureester (5, 9, 13) übergeführt und in Gegenwart von Zinkhalogenid/Ethyldiisopropylamin und eines konjugierten Diens in guten bis sehr guten Ausbeuten in verbrückte Siebenringe (14, 16, 18, 20-24) umgewandelt. Demnach reagiert 5, anders als alle bisher untersuchten Oxyallyl-Vorläufer, unter den beschriebenen Bedingungen zum verbrückten 1-Ethoxy-1,4-cycloheptadien (14, 16, 18, 20) statt zum thermodynamisch stabileren 4-Cyclohepten-1-on (15, 17, 19, 21), welches aus dem anfänglich gebildeten cyclischen Enolether durch Hydrolyse entsteht. Es wird geschlossen, daß jetzt strukturell komplexe Allyl-Kationen unter schonenden Bedingungen erzeugt werden können, dank der Gegenwart von Ethyldiisopropylamin sogar in schwach alkalischem Medium.
    Notes: Allyl alcohols such as 3-ethoxy-2-methyl-3-buten-2-ol (4), the silylated alcohol 8 and also 2-methyl-3-pentyn-2-ol (12) have been converted into the corresponding trifluoroacetates (5, 9, 13), which in the presence of zinc halide/ethyldiisopropylamine react with conjugated dienes to form bridged seven-membered rings (14, 16, 18, 20-24) in good to excellent yields. Thus, unlike all other oxyallyl precursors studied so far, 5 gives the bridged 1-ethoxy-1,4-cycloheptadiene (14, 16, 18, 20) under the present conditions rather than the thermodynamically more stable 4-cyclohepten-1-one (15, 17, 19, 21) which is formed from the initial enol ether by hydrolysis. It is concluded that structurally complex allyl cations can now be generated in very mild conditions, and owing to the presence of ethyldiisopropylamine, even in weakly alkaline solutions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19801131216
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  • 9
    Electronic Resource
    Electronic Resource
    Cycloadditions of allyl cations, 25. Acid catalyzed dehydrative cyclodimerization of 2,4-dimethyl-3-penten-2-ol in two phases. Biomimetic one-pot preparation of 3,3,5,5-tetramethyllimonene (4-isopropenyl-1,3,3,5,5-pentamethyl-1-cyclohexene) (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 1182-1186 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Cycloadditionen von Allyl-Kationen, 25. Säurekatalysierte dehydrative Cyclodimerisierung von 2,4-Dimethyl-3-penten-2-ol in zwei Phasen. Biomimetische Eintopfdarstellung von 3,3,5,5-Tetramethyllimonen (4-Isopropenyl-1,3,3,5,5-pentamethyl-1-cyclohexen)2,4-Dimethyl-3-penten-2-ol (1) wurde in einer Mischung von wäßriger Sulfonsäure/Pentan bei Raumtemperatur gerührt. Es bildete sich 3,3,5,5-Tetramethyllimonen (2) in hoher Ausbeute. 2 wurde in sein Epoxid (3) (4-Isopropenyl-1,3,3,5,5-pentamethyl-7-oxabicyclo[4.1.0]heptan) umgewandelt.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140336
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  • 10
    Electronic Resource
    Electronic Resource
    Cycloadditions of Allyl Cations, 281) Novel Diels-Alder Additions via Acid Catalyzed Reactions of 4-Methyl-3-penten-2-ol with Cyclopentadiene and Cyclohexadiene in Two Phases. Formation of Monocyclic, Bicyclic, and Tricyclic Adducts and Double Fragmentation of a Norbornenylcarbinol (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 2208-2216 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cycloadditionen von Allyl-Kationen, 281) Neuartige Diels-Alder-Additionen: säurekatalysierte Reaktionen von 4-Methyl-3-penten-2-ol mit Cyclopentadien und Cyclohexadien im Zweiphasensystem. Bildung von monocyclischen, bicyclischen und tricyclischen Addukten und Doppelfragmentierung eines Norbornenylcarbinols4-Methyl-3-penten-2-ol (1) und Cyclopentadien reagieren in einem sauren Zweiphasensystem bei 0°C unter Bildung von Allylcyclopentenolen 2 und Norbornenylcarbinolen 4. Bei 50°C und unter ähnlichen Bedingungen werden 2 und 4 in Allylcyclopentadiene 3, bicyclische Olefine 5 und 6 sowie in den tricyclischen Ether 7 umgewandelt. Mit einem vergleichsweise reaktiven Dehydratisierungsagens (SOCl2/Pyridin) erleidet das Norbornenylcarbinol 4 eine doppelte Fragmentierung unter Bildung dimerer Diene C12H20, welche unabhängig durch säurekatalysierte dehydrative Dimerisierung des Allylalkohols 1 erhalten wurden. - Die endo/exo-Selektivität der Bildung der epimeren Norbornenylcarbinole 4 aus Cyclopentadien und 1 und die der AlCl3-katalysierten Cycloaddition von 2-Butensäure-methylester und Cyclopentadien sind gleich (13:1). Die säurekatalysierte Zweiphasenreaktion von Cyclohexadien und 1 bei Raumtemperatur gibt das Substituierte Bicyclo[2.2.2]octen endo-13 mit 19 - 23 Ausbeute.
    Notes: 4-Methyl-3-penten-2-ol (1) and cyclopentadiene react in an acidic two phase system at 0°C to form allylcyclopentenols 2 and norbornenylcarbinols 4. At 50°C and under similar conditions, 2 as well as 4 are equilibrated to allylcyclopentadienes 3, bicyclic olefins 5 and 6, and tricyclic ether 7. With a comparatively reactive dehydrating agent (SOCl2/pyridine), norbornenylcarbinol 4 suffers double fragmentation to give dimeric dienes C12H20, which were also obtained independently by acid catalyzed dehydrative dimerization of allyl alcohol 1. - The endo/exo selectivity for the formation of epimeric norbornenylcarbinols 4 from cyclopentadiene and 1 is similar to that of the AlCl3-catalyzed cycloaddition of methyl 2-butenoate und cyclopentadiene (13:1). The acid catalyzed two phase reaction of cyclohexadiene and 1 at room temperture gives the substituted bicyclo[2.2.2]octene endo-13 in 19 - 23% yield.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140618
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