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  • 1
    Electronic Resource
    Electronic Resource
    Synthesis of α-Cyanoenamines by Cyanation of α-Bromoimmonium Bromides and Dehydrobromination of β-bromo-α-(dialkylamino)nitriles (1983)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 3846-3857 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthese von α-Cyanenaminen durch Cyanierung von α-Bromimmonium-bromiden und Dehydrobromierung von β-Brom-α-(dialkylamino)nitrilenDie Reaktion der α-Bromimmonium-bromide 4 mit Kaliumcyanid in Dimethylformamid gibt β-Brom-α-(dialkylamino)nitrile 5, die in verschiedenen Base-Lösungsmittel-Systemen zu (E)- und (Z)-α-Cyanenaminen 2 dehydrobromiert werden. Eine Modifizierung einer kürzlich veröffentlichten Synthese von α-Cyanenaminen 2 aus Aldehyden über Enamine führte zu einer verbesserten und schnellen Methode für die Darstellung der Titelverbindungen.
    Notes: The reaction of α-bromoimmonium bromides 4 with potassium cyanide in dimethylformamide gave rise to β-bromo-α-(dialkylamino)nitriles 5, which were dehydrobrominated in various basesolvent systems to afford (E)- and (Z)-α-cyanoenamines 2. An adaption of a previously published preparation of α-cyanoenamines starting from aldehydes via enamines led to an improved, efficient and fast synthesis of the title compounds.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19831161208
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  • 2
    Electronic Resource
    Electronic Resource
    Facile Synthesis of 2-Alkoxy-2-aryloxiranes (1983)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 3631-3636 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Eine einfache Darstellung von 2-Alkoxy-2-aryloxiranenTertiäre (α-Bromalkyl)arylketone 1 reagierten mit überschüssigem Kaliumcarbonat in trockenem Alkohol ausschließlich zu den entsprechenden 2-Alkoxy-2-aryloxiranen 4. Silbercarbonat in trockenem Alkohol führte in einer Konkurrenzreaktion zur Bildung von 4 und zu einer semibenzilischen Favorskii-Umlagerung (→5). Dagegen trat mit Silber-hexafluoroantimonat ausschließlich die letztere Umlagerungsreaktion ein.
    Notes: Tertiary α-bromoalkyl aryl ketones 1 were converted into 2-alkoxy-2-aryloxiranes 4 exclusively by reaction with excess potassium carbonate in the corresponding dry alcohol. Silver carbonate in a dry alcohol with these α-bromo ketones yielded competitively formation of 2-alkoxyoxiranes and semi-benzilic Favorskii rearrangement (→5), while silver hexafluoroantimonate in the same medium afforded the latter rearrangement reaction exclusively.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19831161112
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  • 3
    Electronic Resource
    Electronic Resource
    Diademan und Strukturverwandte, II. Katalysierte Umlagerungen und Hydrierungen (1983)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 1377-1385 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Diademane and Structurally Related Compounds, II. Catalytic Rearrangements and HydrogenationsCopper, silver, gold, and rhodium compounds catalyze the rearrangement of diademane (1) to triquinacene (5) and snoutene (7), respectively. Known mechanisms may be adopted to explain this behaviour. The catalytic hydrogenation of 1 leads to a mixture of 6 products, 9-14, the composition of which was independent of the extent of reaction. Adamantane, the thermodynamically most stable isomer of all conceivable “hexahydrodiademanes”, was not detected.
    Notes: Kupfer-, Silber-, Gold- und Rhodiumverbindungen katalysieren die Umlagerung von Diademan (1) zu Triquinacen (5) bzw. Snouten (7). Zur Erklärung können bekannte Mechanismen herangezogen werden. Die katalytische Hydrierung von 1 führt zu den 6 Produkten 9-14 in einer vom Umsetzungsgrad unabhängigen Zusammensetzung. Adamantan, das thermodynamisch stabilste aller möglichen “Hexahydrodiademane”, konnte nicht nachgewiesen werden.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19831160412
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  • 4
    Electronic Resource
    Electronic Resource
    Zur Diels-Alder-Reaktivität von Dispiro[2.0.2.4]deca-7,9-dien und 5,5,6,6-Tetramethyl-1,3-cyclohexadien (1983)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 1897-1905 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Diels-Alder Reactivity of Dispiro[2.0.2.4]deca-7,9-diene and, 5,5,6,6-Tetramethyl-1,3-cyclohexadieneDispiro[2.0.2.4]deca-7,9-diene (2) yields normal Diels-Alder adducts 3-5 with p-benzoquinone, dehydrobenzene, pyridazinedione, phthalazinedione, and 4-phenyl-1,2,4-triazolinedione (PTAD). Its relative diene reactivity against PTAD is approximately 4000 times greater than that of the sterically similar 5,5,6,6-tetramethyl-1,3-cyclohexadiene (10), which is predominantly due to the electronic effect of the spirocyclopropyl groups. On the other hand, 2 is estimated to react about 25-50 times more slowly than 1,3-cyclohexadiene as a consequence of the steric influences of the cyclopropyl groups.
    Notes: Dispiro[2.0.2.4]deca-7,9-dien (2) liefert normale Diels-Alder-Addukte 3-5 mit p-Benzochinon, Dehydrobenzol, Pyridazindion, Phthalazindion und 4-Phenyl-1,2,4-triazolin-3,5-dion (PTAD). Seine relative Dien-Reaktivität gegenüber PTAD ist ca. 4000mal größer als die des sterisch ähnlichen 5,5,6,6-Tetramethyl-1,3-cyclohexadiens (10), was vorwiegend auf den elektronischen Effekt der Spirocyclopropylgruppen zurückzuführen ist. Andererseits reagiert 2 noch schätzungsweise 25 - 50mal langsamer als 1,3-Cyclohexadien als Folge des sterischen Einflusses der Cyclopropylgruppen.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19831160517
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  • 5
    Electronic Resource
    Electronic Resource
    Katalytische Hydrierung einiger Kohlenwasserstoffe mit spiroanellierten Bicyclopropyleinheiten (1983)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 833-837 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Catalytic Hydrogenation of Some Hydrocarbons with Spiroanellated Bicyclopropyl UnitsThe spirocyclopropyl groups of dispiro[2.0.2.4]dec-8-ene (1) and dispiro[cyclopropane-1,2′-bicyclo[2.2.0]hexane-3′, 1″-cyclopropane] (11) both upon catalytic hydrogenation are ringopened to ethyl groups rather than gem-dimethyl groups as would be expected from literature precedents. The unusual behaviour is caused by a so-called anchor effect, i. e. preferred adsorption on the catalyst's surface occurs at the site of the C=C double bond in 1 and the most highly strained C—C single bond in 11 respectively thereby determing the rate and direction of hydrogen addition to the cyclopropyl bonds.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19831160241
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  • 6
    Electronic Resource
    Electronic Resource
    Diademan und Strukturverwandte, I. Darstellung und charakteristische Reaktionen einiger Tris-σ-homobenzol-Kohlenwasserstoffe (1983)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 587-609 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Diademane and Structurally Related Compounds, I Preparation and Characteristic Reactions of Some Tris-σ-homobenzene HydrocarbonsDiademane (5) and 1,6-Homodiademane (6) are the first hydrocarbons with cis-tris-σ-homobenzene skeletons. They were prepared by photoisomerization of the olefinic precursors 8 („snoutene“) and 15 („4,5-homosnoutene“), respectively. In an analogous reaction the bridged trans-tris-σ-homobenzene 7 was formed from 17 („endo,exo-bishomobarrelene“). 7 is more easily obtained from 17 by rhodium(I)-catalyzed isomerization or from exo,exo-bishomobarrelene 18 by thermal rearrangement. The unbridged 4 was prepared using a newly developed synthetic sequence starting from 1,3-cyclohexadiene. The thermal rearrangement of 5 and 6 to triquinacene (9) and 1,10-homotriquinacene (16) is very facile; the gas phase kinetic parameters (ln k (5) = 33.7 - 31600/RT and ln k (6) = 32.2 - 28300/RT, both first order) strongly corroborate, that these rearrangements are concerted [σ2a + σ2a + σ2s]-Cycloreversions. [3,6-12C2]-labelled 4 upon thermolysis yields a trans-bicyclo[4.3.0]nona-3,7-diene (31 ≙ 22) with a 12C-labelling pattern, which proves its formation via a 3-step mechanism. The first step in this sequence most probably is a [σ2s + σ2s + σ2a] cycloreversion with ln k = 30.8 - 42000 RT(first order). Only the bridged compound 7 does not follow the same path, probably due to excessive ring strain in the transition state, and prefers a stepwise [2 + 2] cycloreversion leading to 18 and at least 5 secondary products.
    Notes: Diademan (5) und 1,6-Homodiademan (6), die ersten Kohlenwasserstoffe mit cis-Tris-σ-homo-benzol-Gerüst, wurden durch Photoisomerisierung der monoolefinischen Vorstufen 8 („Snouten“) bzw. 15 („4,5-Homosnouten“) gewonnen. Analog entstand aus 17 („endo,exo-Bis-homobarrelen“) das überbrückte trans-Tris-σ-homobenzol 7, das sich bequemer auch durch Rhodium(I)-katalysierte Isomerisierung von 17, oder thermische Umlagerung von exo,exo-Bishomobarrelen 18 erhalten ließ. Das nicht überbrückte 4 wurde nach einer neuen Synthesesequenz aus 1,3-Cyclohexadien dargestellt. Thermisch lagern sich 5 und 6 sehr leicht in Triquinacen (9) bzw. 1,10-Homotriquinacen (16) um, die gasphasen-kinetischen Parameter (In k (5) = 33.7 - 31600/RT und in k (6) = 32.2 - 28300/RT, beide 1. Ordnung) lassen auf konzertiert verlaufende [σ2s + σ2s + σ2s]-Cycloreversionen schließen. [3,6-12C2]-markiertes 4 liefert bei der Thermolyse ein trans-Bicyclo[4.3.0]nona-3,7-dien (31 ≙ 22) mit einem 12C-Markierungsmuster, das einen dreistufigen Bildungsmechanismus beweist. Dabei ist der erste Schritt wahrscheinlich eine [σ2s + σ2s + σ2s]-Cycloreversion mit ln k = 30.8 - 42000/RT (1. Ordnung). Nur das überbrückte 7 weicht diesem Umlagerungstyp aus und erfährt - offenbar aus Gründen der Ringspannung - eine schrittweise verlaufende [2 + 2]-Cycloreversion zu 18 und mindestens 5 Folgeprodukten.
    Additional Material: 6 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19831160219
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  • 7
    Electronic Resource
    Electronic Resource
    Beitrag zur Chemie der Phosphor-Stickstoff-Verbindungen. Reaktion von Cl2(O)P—NH—P(O)Cl2 mit Tetrahydrofuran (1983)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 501 (1983), S. 191-198 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Contribution to the Chemistry of Phosphorus-Nitrogen Compounds. Reaction of Cl2(O)P—NH—P(O)Cl2 with TetrahydrofuranAs well as many phosphorus compounds, the imidodiphosphoryl tetrachloride HN(P(O)Cl2)2 reacts with a large excess of tetrahydrofuran to give the polytetrahydrofuran. Otherwise, if we use smaller molecular ratios THF/HN(P(O)Cl2)2 (1/2 to 3) a polytetrahydrofuran with short chains and N(ω-hydroxypolytetramethylenoxy)imidodiphosphoryl tetrachloride R—N(P(O)Cl2)2; R = H(O(CH2)4)n- are obtained at 22° or 30°C.The 1H and 31P n.m.r. spectra show that oxonium ions are formed with progressive additions of THF to HN(POCl2)2/CCl4 solution. Then two mechanisms have been considered by nucleophilic attack on carbon α of oxonium ion coming from: the free electronic dublett on oxygen of THF to give polytetrahydrofuran or (and) from the nitrogen of imido diphosphoryl tetra chloride anion ((Cl2OP)2N)- to obtain N(ω-hydroxypolytetramethylenoxy)imidodiphosphoryl tetrachloride.
    Notes: Wie im Falle vieler Phosphorverbindungen führt die Reaktion des Imidodiphosphoryltetrachlorids mit einem großen Überschuß Tetrahydrofuran zur Polymerisation des letzteren. Arbeitet man hingegen mit kleinen THF/HN(P(O)Cl2)2 Molverhältnissen (1/2 bis 3), so entsteht bei 22°C bzw. 30°C neben kurzen Poly-THF-Ketten N(ω-hydroxypolytetramethylenoxy)imidodiphosphoryltetrachlorid R—N(P(O)Cl2)2; R = H(O(CH2)4)n-. 1H- und 31P-NMR-Spektren bei stufenweiser Zugabe von THF zu einer HN(P(O)Cl2)2/CCl4-Lösung zeigen, daß sich ein Oxonium-Komplex bildet, der einen nukleophilen Angriff auf das in α-Stellung zum Sauerstoff stehende Kohlenstoffatom durch das Sauerstoffatom des THF oder durch das Stickstoffatom des (N(P(O)Cl2)2)--Anions bewirkt.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19835010623
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  • 8
    Electronic Resource
    Electronic Resource
    Phosphoryl Complexes of Some Metal(II) Trifluoromethanesulfonates (1983)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 503 (1983), S. 201-206 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Phosphoryl-Komplexe einiger Metall(II)-TrifluoromethansulfonateCobalt(II)-, Nickel(II)-, Kupfer(II)- und Zink(II)-trifluoromethansulfonate bilden Komplexe mit den Phosphoryl-Liganden Hexamethylphosphorsäuretriamid, Nonamethylimidodiphosphorsäuretetramid, Trimorpholinophosphinoxid, Tributhylphosphinoxid und Triphenylphosphinoxid. Die Verbindungen wurden durch eine Substitutionsreaktion dargestellt unter Verwendung von Trialkylorthoformiat als Dehydratationsmittel und mit Hilfe der IR- und Elektronenspektroskopie untersucht. In allen Verbindungen werden die Liganden über die Phosphoryl-Sauerstoffatome koordiniert. In einigen Komplexen sind die Trifluoromethansulfonat-Anionen (halb-) koordiniert an die Metallionen. Die Koordination um die Metallionen ist tetraedrisch, quadratischpyramidal oder oktaedrisch in Abhängigkeit von der Metallion-Liganden-Kombination. In seinem Koordinationsverhalten ähnelt das CF3SO3--Ion dem Perrhenat-Ion.
    Notes: Cobalt(II), nickel(II), copper(II), and zinc(II) trifluoromethanesulfonates form complexes with the phosphoryl ligands hexamethylphosphoric triamide, nonamethyl imidodiphosphoric tetramide, trimorpholinophosphine oxide, tributylphosphine oxide, and triphenylphosphine oxide. The compounds have been prepared by a substitution reaction using trialkyl orthoformates as dehydrating agents and were investigated with the aid of infrared and ligand-field spectroscopy. In all compounds the ligands coordinate via the phosphoryl oxygen atoms. In some complexes the trifluoromethanesulfonate anions are (semi-)coordinated to the metal ions. The coordination around the metal ions was found to be tetrahedral, square pyramidal, or octahedral depending on the particular combination of metal ion and ligand. In its coordination behaviour the CF3SO3- ion resembles the perrhenate ion.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19835030821
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  • 9
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    Platelet thromboxane synthetase inhibitors with low doses of aspirin: possible resolution of the "aspirin dilemma" (1983)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1983-04-29
    Description: Selective pharmacological inhibition of thromboxane A2 synthesis did not prevent arachidonate-induced aggregation of human platelets in vitro. Prevention was instead achieved by a combination of thromboxane A2 inhibitors with low concentrations of aspirin. The latter partially reduced the proaggregatory cyclooxygenase products that accumulated when thromboxane A2 synthesis was blocked. The aspirin concentrations did not affect per se either platelet aggregation or prostacyclin synthesis in cultured human endothelial cells. The combination of thromboxane synthetase inhibitors with low doses of aspirin may offer greater antithrombotic potential than either drug alone.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Bertele, V -- Falanga, A -- Tomasiak, M -- Dejana, E -- Cerletti, C -- de Gaetano, G -- New York, N.Y. -- Science. 1983 Apr 29;220(4596):517-9.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/6682245" target="_blank"〉PubMed〈/a〉
    Keywords: Aspirin/*pharmacology ; Blood Platelets/*drug effects/enzymology ; Dose-Response Relationship, Drug ; Drug Interactions ; Humans ; Imidazoles/pharmacology ; Methacrylates/pharmacology ; Oxidoreductases/*antagonists & inhibitors ; Platelet Aggregation/drug effects ; Thromboxane-A Synthase/*antagonists & inhibitors
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
    Published by American Association for the Advancement of Science (AAAS)
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  • 10
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    Mechanical action of the intercostal muscles on the ribs (1983)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1983-04-01
    Description: The external and internal interosseous intercostal muscles were separately stimulated at end-expiratory lung volume in anesthetized dogs. These muscles were all found to elevate the ribs into which they insert. By attaching weights to the ribs, it was determined that the nonlinear compliance of the ribs was responsible for this phenomenon.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉De Troyer, A -- Kelly, S -- Zin, W A -- New York, N.Y. -- Science. 1983 Apr 1;220(4592):87-8.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/6828883" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Biomechanical Phenomena ; Dogs ; Electric Stimulation ; Humans ; Intercostal Muscles/anatomy & histology/*physiology ; Respiration ; Ribs/anatomy & histology/*physiology
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
    Published by American Association for the Advancement of Science (AAAS)
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