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  • Chemistry  (9)
  • Oral epithelium  (1)
  • STRUCTURAL MECHANICS  (1)
  • 1975-1979  (11)
  • 1978  (11)
  • 1
    Electronic Resource
    Electronic Resource
    Synthese und einige Eigenschaften von Aza[17]annulenen (1978)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 111 (1978), S. 84-98 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Some Properties of Aza[17]annulenesAddition of ethoxycarbonylnitrene to dimeric cyclooctatetraene C16H16 (1) leads to three mono-adducts 2, 3, and 4, 3 is transformed (in pentane solution) during low temperature photolysis mainly into N-(ethoxycarbonyl)aza[17]annulene 5. In the same reaction 4 yields 6 and some 5. It is possible to propose a configuration for 5 but not for 6. Treatment of 5 and 6 with potassium tert-butoxide affords the same aza[17]annulenyl anion (8) the configuration of which is proven by its 1H NMR spectrum. Contrary to 5 and 6, the nitrogen in 8 occupies an internal position. 1H-1-Aza[17]annulene 11 with an internal position of the NH-group is generated upon protonation of 8 with acetic acid. However, a 1H-1-aza[17]annulene 13 which reveals an external arrangement of the NH-group is available via UV irradiation of the two tetracyclic aziridines 12 and 14. With methyl iodide, 8 is N-methylated to 15. This reaction has to be preceded by an isomerization which brings nitrogen in 8 from an internal into an external position. - The differences of the chemical shifts for inner and outer protons as well as the question of configurational and conformational stability are briefly discussed for aza[17]annulenes 5, 6, 8, 11, 13, and 15.
    Notes: Bei der Addition von Ethoxycarbonylnitren an dimeres Cyclooctatetraen C16H16 (1) entstehen drei Monoaddukte 2, 3 und 4. Bei der Tieftemperaturphotolyse bildet sich aus 3 (in Pentan) ganz überwiegend N-(Ethoxycarbonyl)aza[17]annulen 5, aus 4 entsteht neben 6 etwas 5. Ein Konfigurationsvorschlag kann nur für 5 und nicht für 6 gegeben werden. Mit Kalium-tert-butylat bildet sich aus 5 und 6 das gleiche Aza[17]annulenyl-Anion (8), dessen Konfiguration aus dem 1H-NMR-Spektrum hervorgeht. Der Stickstoff besetzt in 8 im Gegensatz zu 5 und 6 eine interne Position. Mit Essigsäure erhalten wir aus 8 das 1H-1-Aza[17]annulen 11 mit interner Stellung der NH-Gruppe. Die Photolyse der beiden tetracyclischen Aziridine 12 und 14 bringt dagegen ein 1H-1-Aza[17]annulen 13 mit nunmehr externer Anordnung der NH-Gruppe hervor. Bei der Einwirkung von Methyliodid auf 8 beobachten wir N-Methylierung zu 15, der jedoch Isomerisierung des Stickstoffs aus einer internen in eine externe Position vorausgehen muß.  -  Die Unterschiede in den chemischen Verschiebungen von inneren und äußeren Protonen sowie die Konfigurations- und Konformationsstabilität bei den Aza[17]annulenen 5, 6, 8, 11, 13 und 15 werden kurz diskutiert.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19781110108
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  • 2
    Electronic Resource
    Electronic Resource
    Über Cycloheptadecaoctaene und [17]Annulenyl-Anionen (1978)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 111 (1978), S. 107-124 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cycloheptadecaoctaenes and [17]Annulenyl AnionsThe dimer 1 of cyclooctatetraene reacts with “methylene” and ethoxycarbonylcarbene to yield different monoadducts 2 and 7-10. From the esters 7-10 the acids 11-13 are available. All endocyclic σ-bonds of the tetracyclic compounds 2,8,11-13 are cleaved by UV light with formation of the cycloheptadecaoctaenes 15-17.17 decarboxylates in acetone cleanly to give crystalline cycloheptadecaoctaene (18). In the presence of bases, the carbon acids 15 and 18 are converted into the [17] annulenyl anion (19). An analogous behaviour is shown by 20 and 22 which yield the same mixture of methyl[17]annulenyl anions (21). Some properties of the seventeen-membered higher vinylogues of cyclopentadiene and cyclopentadienyl anion are investigated.
    Notes: Dimeres Cyclooctatetraen 1 reagiert mit „Methylen“ und Ethoxycarbonylcarben zu verschiedenen Monoaddukten 2 und 7-10. Aus den Estern 7-10 sind die Säuren 11-13 zugänglich. In den Tetracyclen 2, 8, 11-13 brechen unter der Einwirkung von UV-Licht alle endocyclischen σ-Bindungen auf. Es entstehen die Cycloheptadecaoctaene 15-17. 17 decarboxyliert in Aceton glatt zum kristallinen Cycloheptadecaoctaen (18). Die Kohlenstoffsäuren 15 und 18 bilden in Gegenwart von Basen das [17]Annulenyl-Anion (19). Analoges Verhalten zeigen 20 und 22. Man erhält das gleiche Gemisch von Methyl[17]annulenyl-Anionen (21). Einige Eigenschaften der siebzehn-gliedrigen höheren Vinylogen des Cyclopentadiens und Cyclopentadienyl-Anions werden untersucht.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19781110110
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  • 3
    Electronic Resource
    Electronic Resource
    Syntheseversuche von all-cis-1,2,3-Triformylcyclopropan und all-cis-1,2,3,4-Tetraformylcyclobutan (1978)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 111 (1978), S. 2448-2450 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Some Experiments to Generate all-cis-1,2,3-Triformylcyclopropane and all-cis-1,2,3,4-TetraformylcyclobutaneOzonolysis of bullvalene (3) and the dimer 6 of COT followed by reduction should generate all-cis-1,2,3-triformylcyclopropane (4) and all-cis-1,2,3,4-tetraformylcyclobutane (7). We have been unable to isolate 4 and 7. 4 escapes via an intermolecular “polymerisation” and 7 cyclizes intramolecularly giving the tetracyclic acetal 2b of all-cis-1,2,3,4-tetraformylcyclobutane.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19781110640
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  • 4
    Electronic Resource
    Electronic Resource
    Werkstoffanstrengung im Hertz'schen Kontakt infolge Last- und Eigenspannungen (1978)
    Weinheim : Wiley-Blackwell
    Materialwissenschaft und Werkstofftechnik 9 (1978), S. 210-214 
    Details
    ISSN: 0933-5137
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Material Stressing in a Hertzian Contact - Influence of Load and Internal StressesFor the analysis of the material stressing in a Hertzian Contact due to elliptically distributed normal load it is sufficient to calculate the stresses at z ≥ 0, × = y = 0. At this point the maximum stress occurs in the contact surface as well as in the stressed volume. From the center to the rim of the contact the stress decreases.In the case of residual stresses in the material it is necessary to calculate the resulting stresses in the entire contact area. The superposition of stresses due to load and internal stresses can cause stressings of the material with a maximum in the region of the rim of the contact area. The calculation of the conditions in the center alone can lead to misinterpretations.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mawe.19780090607
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  • 5
    Electronic Resource
    Electronic Resource
    Quantitative analysis of squamous epithelium of normal palatal mucosa in guinea pigs (1978)
    Springer
    Cell & tissue research 190 (1978), S. 223-233 
    Details
    ISSN: 1432-0878
    Keywords: Oral epithelium ; Epithelial differentiation ; Stereology ; Guinea pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The epithelium of intact guinea pig palate was subjected to stereologic analysis in a study of structural alterations in the keratinizing epithelium in response to wounding. Point counting procedures were employed to analyse electron micrographs sampled from three epithelial strata in biopsies collected from five animals. The differentiation pattern of the guinea pig palate epithelium displayed the following structural density gradients from basal to granular layers: descending gradients of metabolically active organelles, ascending gradient of bundled filaments coupled with the appearence of membrane coating granules and keratohyalin granules, and a plateau-like gradient of cytoplasmic ground substance. This pattern of epithelial differentiation is basically identical to that of human hard palate epithelium and epidermis. Regional and species variations in structure of keratinizing epithelia are suggested based on interepithelial differences in morphometric parameters.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00218171
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  • 6
    Electronic Resource
    Electronic Resource
    Hoffmann, M., Krömer, H., Kuhn, R., Polymeranalytik I; Makromolekulare Strukturen; Physikalische Methoden; Anwendungskriterien. 1. Aufl., XV, 438 S., 103 Abb., 10 Tab. Georg Thieme Verlag, Stuttgart 1977. Thieme Taschenlehrbuch der organischen Chemie. B: Spezielle Gebiete, Band 4. flex. 28,80 DM (1978)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 320 (1978), S. 352-352 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19783200229
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  • 7
    Electronic Resource
    Electronic Resource
    Einige Reaktionen von Bicyclo[6.2.0]deca-1,3,5,7,9-pentaenen (1978)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1978 (1978), S. 1379-1389 
    Details
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Some Reactions of Bicyclo[6.2.0]deca-1,3,5,7,9-pentaenes9,10-Dimethylbicyclo[6.2.0]deca-1,3,5,7,9-pentaene (6) is accessible via several very similar routes. Its pyrolysis yields besides 1,2-dimethylazulene (10), 1,2- and 2,3-dimethylnaphthalene (12 and 11, respectively) The behavior of 6 in the presence of some π-electron acceptors, reactive dienophiles, Fe3(CO)12 and Fe2(CO)9 is described. Finally, several tricarbonyliron complexes of 9-chloro-10-methylbicyclo[6.2.0]deca-1,3,5,7,9-pentaene (4) are presented.
    Notes: 9,10-Dimethylbicyclo[6.2.0]deca-1,3,5,7,9-pentaen (6) ist auf mehreren sehr ähnlichen Wegen zugänglich. Bei der Pyrolyse entsteht 1,2-Dimethylazulen (10), aber auch 1,2- und 2,3-Dimethylnaphthalin (12 bzw. 11). Das Verhalten von 6 gegenüber einigen π-Elektronenakzeptoren, reaktiven Dienophilen, Fe3(CO)12 und Fe2(CO)9 wird beschrieben. Schließlich wird noch kurz auf einige Tricarbonyleisenkomplexe von 9-Chlor-10-methylbicyclo[6.2.0]deca-1,3,5,7,9-pentaen (4) eingegangen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.197819780904
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  • 8
    Electronic Resource
    Electronic Resource
    Annulene, 28. Synthese von Fluor[18]annulen und 1,2-Dihalogen[18]annulenen sowie Versuche zur Darstellung von 1,2-Diaza[16]annulenen (1978)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1978 (1978), S. 1368-1378 
    Details
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Annulenes, 28.  -  Synthesis of Fluoro[18]annulene and 1,2-Dihalo[18]annulenes and Attempted Synthesis of 1,2-Diaza[16]annulenesThe dimer 1 of cyclooctatetraene and 1,1-difluoroethylenes 2a, 2b yield, inter alia, the cycloadducts 3a, 3b. The compound 3c is readily accessible from 3a and (Bu)3SnH. The cycloadducts 3a-3c dehalogenated to 6a-6c, photolysis of which affords fluoro-, 1-chloro-2-fluoro- and 1,2-difluoro[18]annulene (7c, 7a and 7b, respectively). The 1H-NMR spectroscopic behavior of the latter compounds is discussed.  -  The strained double bond of the four-membered ring of 8 reacts with tetrazine 9 to give 11-13. The pyridazine derivative 10 is postulated as an intermediate in the reaction. Only 10  -  and not one of the secondary products 11-13  -  could be a potential precursor of a 1,2-diaza[16]annulene.
    Notes: Aus dimerem Cyclooctatraen 1 und den 1,1-Difluorethylenen 2a, 2b bilden sich unter anderem die Cycloaddukte 3a, 3b. Aus 3a ist mit (Bu)3SnH 3c zugänglich. Die Verbindungen 3a-3c lassen sich zu 6a-6c dehalogenieren. Unter der Einwirkung von UV-Licht entstehen daraus Fluor-, 1-Chlor-2-fluor- und 1,2-Difluor[18]annulen (7c, 7a bzw. 7b), deren charakteristisches 1H-NMR-spektroskopisches Verhalten beschrieben wird.  -  Die gespannte Vierringdoppelbindung in 8 reagiert mit dem Tetrazin 9. Es entstehen 11-13. Das Pyridazinderivat 10 wird als Zwischenstufe postuliert. Nur 10  -  nicht aber eines der Folgeprodukte 11-13  -  wäre ein potentieller Vorläufer eines 1,2-Diaza[16]annulens.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.197819780903
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  • 9
    Electronic Resource
    Electronic Resource
    Über Synthesen und einige Eigenschaften von mono- und disubstituierten Bicyclo[4.2.2]decatetraenen (1978)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1978 (1978), S. 2074-2087 
    Details
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses and Some Properties of Mono- and Disubstituted Bicyclo[4.2.2]decatetraenesWe report the syntheses of the mono- and disubstituted bicyclo[4.2.2]decatetraenes 12 ⇌ 13, 14 ⇌ 15, 16, 17 ⇌ 18, 24 and 19, 20, respectively. The Diels-Alder/retro-Diels-Alder reaction possible in these molecules gives rise to a detectable equilibrium mixture between two valence isomers in the case of 12 ⇌ 13, 14 ⇌ 15 and 17 ⇌ 18. The half-lives of the molecules 13, 18, and 24 at 35°C are of the order of 13 to 24 minutes.  -  We also describe some experiments designed to detect a didehydrobicyclo[4.2.2]decatetraene 37 or 38.
    Notes: Wir berichten über die Darstellungen der mono- und disubstituierten Bicyclo[4.2.2]decatetraene 12 ⇌ 13, 14 ⇌ 15, 16, 17 ⇌ 18, 24 bzw. 19, 20. Die in diesen Molekülen mögliche Diels-Alder/Retro-Diels-Alder-Reaktion führt bei 12 ⇌ 13, 14 ⇌ 15, 17 ⇌ 18 zu einem nachweisbaren Gleichgewichtsgemisch zwischen zwei Valenzisomeren. Die Halbwertszeiten der Verbindungen 13, 18 und 24 liegen bei 35°C zwischen ca. 13 bis 24 Minuten.  -  Wir informieren ferner über einige Versuche zum Nachweis eines Didehydrobicyclo[4.2.2]decatetraens 37 oder 38.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.197819781221
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  • 10
    Electronic Resource
    Electronic Resource
    Determination of choline and acetylcholine in distinct rat brain regions by stable isotope dilution and field desorption mass spectrometryQuantitative Field Desorption Mass Spectrometry: Part IX; for Part VIII, see (Ref. 38). (1978)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 5 (1978), S. 591-595 
    Details
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The determination of choline and acetylcholine by field desorption mass spectrometry from rat brain tissue samples has been demonstrated. Essential points of the assay are the use of stable isotope labelled internal standards, a simple ion pair extraction procedure, direct analysis of the quaternary ammonium ions without derivatization, and accumulation of the electrically recorded field desorption ion signals with a multi-channel analyser. The analysis of sample amounts in the picogram range gave quantitative data of good precision (0.6-10% standard deviation).
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200051009
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