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  • Organic Chemistry  (14)
  • Polymer and Materials Science  (2)
  • [abr] PI-PLC; Phosphatidylinositol specific phospholipase C  (2)
  • 1
    Electronic Resource
    Electronic Resource
    Cell membrane, but not circulating, carcinoembryonic antigen is linked to a piiosphatidylinositol-containing hydrophobic domain
    Amsterdam : Elsevier
    Biochemical and Biophysical Research Communications 155 (1988), S. 794-800 
    Details
    ISSN: 0006-291X
    Keywords: [abr] CEA; carcinoembryonic antigen ; [abr] CRD; cross-reacting determinant ; [abr] G-PI; glyco-phosphatidylinositol ; [abr] NCA; normal cross-reacting antigen ; [abr] PBS; phosphate buffered saline ; [abr] PI-PLC; Phosphatidylinositol specific phospholipase C
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1016/S0006-291X(88)80565-5
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  • 2
    Electronic Resource
    Electronic Resource
    Cell membrane, but not circulating, carcinoembryonic antigen is linked to a piiosphatidylinositol-containing hydrophobic domain
    Amsterdam : Elsevier
    Biochemical and Biophysical Research Communications 155 (1988), S. 794-800 
    Details
    ISSN: 0006-291X
    Keywords: [abr] CEA; carcinoembryonic antigen ; [abr] CRD; cross-reacting determinant ; [abr] G-PI; glyco-phosphatidylinositol ; [abr] NCA; normal cross-reacting antigen ; [abr] PBS; phosphate buffered saline ; [abr] PI-PLC; Phosphatidylinositol specific phospholipase C
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1016/S0006-291X(88)80565-5
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  • 3
    Electronic Resource
    Electronic Resource
    Reductions of Tetrahalo-1,3,5,7-tetramethyl-anti-tricyclo [5.1.0.03,5]octane-2,6-diones. 1,3,5,7-Tetramethyl-anti-tricyclo[5.1.0.03,5]octane-2,6-dioneThe trivial name is anti-bis-homoduroquinone; this nomenclature was used in previous publications (compare [1]).In part from the planned dissertation of R. A. Dyllick-Brenzinger, ETH Zürich. (1976)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 59 (1976), S. 1311-1327 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Methoden zur Entfernung von Halogenatomen aus den leicht zugänglichen (Bis-homo-p-chinon)-Derivaten 4,4,8,8-Tetrachlor- (4) und 4,4,8,8-Tetrabrom-1,3,5,7-tetramethyl-anti-tricyclo[5.1.0.03,5]octan-2,6-dion (5) wurden untersucht. Mit LiAlH4 bzw. mit KFeH(CO)4, NaBH3CN oder CrCl2 entstanden Diole bzw. Diketone, in denen ohne Gerüstveränderung verschiedene Halogenatome durch Wasserstoffatome ersetzt worden waren. Die Diole wurden entweder isoliert oder zu den Diketonen aufoxydiert. Von den neun möglichen Dehalogenierungsmustern (Diketone mit unverändertem C-Skelett) liessen sich acht beobachten, sechs davon (8 bis 13) aus 4 und sechs (14 bis 18, 6) aus 5. Nur KFeH(CO)4 entfernte alle vier Halogenatome und dies nur aus dem Tetrabrom-dion 5, wobei das noch unbekannte anti-Isomere von 1,3,5,7-Tetramethyl-tricyclo[5.1.0.03,5]octan-2,6-dion (6) entstand.Die Zuordnung der endo- oder exo-Konfigurationen der nicht-entfernten Halogenatome an den Cyclopropanringen erfolgte auf Grund von 1H-NMR.-Spektraleigenschaften. Als Basisargument diente eine H/13C-Kopplung von 4,5 Hz zwischen exo-H—C(4) und den cis-vicinalen Methyl-Kohlenstoffatomen, welche im 13C-NMR.-Spektrum von 12 beobachtbar ist. Daraus und aus unterschiedlichen Linienbreiten der 1H-NMR.-Signale von endo- und exo-Protonen wurde abgeleitet, dass endo-H immer bei tieferem Feld absorbiert als exo-H. Im Fall von 6 liess sich dies durch geeignete Vergleiche unter Anwendung eines abschirmenden Effektes der angulären Methylgruppen auf exo-H bestätigen. Die Konfigurationen der Hydroxylgruppen in den Diolen 19 bis 22 und 24 bis 27 wurden aufgrund von Symmetrieüberlegungen bestimmt.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19760590434
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  • 4
    Electronic Resource
    Electronic Resource
    Reactions of 1,3,5,7-Tetramethyl-anti-tricyclo[5.1.0.03,5] octane-2,6-diols and their 4,4,8,8-Tetrachloro- and 4,8-Dichloro-Derivatives with Diphosphorus TetraiodideFrom the planned dissertation of R. A. Dyllick-Brenzinger, ETH Zürich. (1977)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 60 (1977), S. 1403-1415 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reaktionen von 1,3,5,7-Tetramethyl-anti-tricyclo[5.1.0.03,5]octan-2,6-diolen und deren 4,4,8,8-Tetrachlor- und 4,8-Dichlorderivaten mit DiphosphortetrajodidEs wurden die P2I4-Reaktionen mit 1,3,5,7-Tetramethyl-anti-tricyclo[5.1.0.03,5]-octan-2,6-diolen (3/6), mit dem 4,8-Dichlorderivat 4 und mit den 4,4,8,8-Tetrachlorderivaten 5/7 untersucht. Dabei entstanden die Styrolderivate 9 und 12, die anti-Bishomobenzolderivate 8 und 11, ein Homotropylidenderivat 10, ein Cyclo-octatetraenderivat 13 und ein 9-Oxabicyclo[4.2.1]nona-2,4,7-trienderivat 15. Die Ausbeuten lagen zwischen 1 und 10%. Die Bildung aller dieser Produkte liess sich unter der Annahme der primären Umwandlung einer oder beider Hydroxylgruppen in Abgangsgruppen X oder X und Y (wahrscheinlich X=Y=I) mechanistisch deuten. Die Reaktion der Deschlorderivate 3/6 lieferte nach Substitution beider Hydroxyl-gruppen durch X und Y: (a) unter Abspaltung von HX und HY das Styrolderivat 9 (Schema 2) und (b) unter Abspaltung von XY das Homotropylidenderivat 10 (Schema 3a) und das Bishomobenzolderivat 8 (Schema 3b). Die Reaktion des 4,8-Dichlor-derivates 4 lieferte nach Substitution beider Hydroxylgruppen durch X und Y: (a) unter Abspaltung von HX und HY das Styrolderivat 12 (Schema 2), und (b) unter Abspaltung von XY das Bishomobenzolderivat 11 (Schema 3b). Die Reaktion mit den 4,4,8,8-Tetrachlorderivaten 5/7 lieferte: (a) nach Substitution beider Hydroxyl-gruppen durch X und Y unter Abspaltung von XCl und YCl das Cyclooctatetraen-derivat 13 (Schema 4), und (b) nach Substitution nur einer Hydroxylgruppe durch X unter Abspaltung von XCl und HCl das bicyclische Derivat 15 (Schema 5). Alle diese Reaktionen sind zusätzlich zu den angegebenen Fragmentierungen und Eliminierungen noch teilweise von Umlagerungen des Kohlenstoffgerüstes begleitet.Die thermische Umlagerung von 1,5-Dichlor-2,4,6,8-tetramethyl-cycloocta-1,3,5,7-tetraen (13) in das Styrolderivat 12 wurde in Abhängigkeit der Lösungs-mittelpolarität untersucht und mit der analogen thermischen Umlagerung von Brom-cyclooctatetraen und Chlor-cyclooctatetraen verglichen.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19770600432
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  • 5
    Electronic Resource
    Electronic Resource
    Stabilisation et caractérisation des polybutadiènes-1,2 liquides cyanométhylés par réaction couplée à l'hydroborationCe mémoire fait état de résultats décrits dans la thèse d'Ingénieur Docteur soutenue par Monsieur J. Vassort et s'insère dans un programme de recherche financé pour la D. G. R. S. T.En hommage au Professeur Kämmerer pour son 65eme anniversaire (1976)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 177 (1976), S. 3119-3137 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Polydienes modified by a reaction coupled with hydroboration contain residual, highly reactive trialkylborane structures making these products instable in air. In the case of cyanomethylated polydienes obtained by this way, elimination of the residual trialkylborane structures by a selective, specific, and quantitative method was investigated: optimation of the cyanomethylation reaction did not result in a quantitative elimination and the acetolysis was found under various conditions not be to quantitative or specific, whereas alcaline oxidation reaction could be shown to be specific and quantitative but not completely selective: it induces, with low yields, a secondary hydrolysis reaction of the cyanomethylated structures. The products obtained by this last method and their acetylated and reduced derivatives were characterized by spectrographic analysis (IR and NMR).
    Notes: L'existence de structures trialkylboranes résiduelles dans les polydiènes modifiés par réaction couplée à l'hydroboration confère aux produits obtenus une instabilité résultant de la réactivité de ces structures à l'air. Pour les polydiènes cyanométhylés par cette voie, une méthode d'élimination des structures trialkylboranes par une réaction sélective, spécifique et quantitative a été recherchée: l'optimisation de la réaction de cyanométhylation n'a pas permis une élimination quantitative; l'acétolyse est, selon les conditions, non quantitative ou non spécifique tandis que la réaction d'oxydation alcaline s'est révélée spécifique et quantitative mais non totalement sélective: elle provoque simultanément et à de faibles taux l'hydrolyse parasite des structures cyanométhylées. La caractérisation des produits obtenus par cette dernière methode a été réalisée par analyse spectrographique (IR et NMR) des produits eux-měmes, de leurs dérivés acétylés et de leurs dérivés réduits.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1976.021771103
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  • 6
    Electronic Resource
    Electronic Resource
    New route for the preparation of block and graft polymers of olefins and vinyl monomers with high efficiency. I. Polyethylene/polymethylmethacrylate (1970)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 137 (1970), S. 229-243 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Katalysatoren des ZIEGLER-NATTA-Typs wurden bei der Synthese von Blockcopolymeren aus Olefinen angewendet. Vor kurzem wurden Blockcopolymere aus Olefinen und Vinylmonomeren hergestellt, wobei die aus der anionischen Polymerisation stammenden „lebenden“ Enden in freie Radikale überführt wurden, die dann die Polymerisation der Vinylmonomeren starten.Die Ausbeute an Blockcopolymeren überschreitet jedoch kaum einige Prozent, da bekanntlich die Anzahl „lebender“ Ketten sehr gering ist. Es wurde gefunden, daß das Zufügen eines passenden Kettenüberträgers wie Zinkdiäthyl während der koordinativen Polymerisation die Anzahl der „aktiven“ Zentren, die fähig sind, in Gegenwart von radikalischen Initiatoren die Polymerisation der Vinylmonomeren zu initiieren, beträchtlich erhöht. Dieser neue Weg ermöglicht hohe Ausbeuten von Blockcopolymeren mit unterschiedlichem Vinylmonomerengehalt. Außerdem ist es möglich, unter gewissen Bedingungen entweder Block- oder Block- und Pfropf- oder sogar ausschließlich Pfropfcopolymere herzustellen.Die Bildung der entsprechenden Homopolymeren kann weitgehend verhindert werden. Als Beispiel dieser neuen Technik wird hier nur die Synthese von Polyäthylen/Polymethylmethacrylat Block- und/oder Pfropfcopolymeren beschrieben, obschon eine ganze Reihe anderer Copolymerer untersucht wurde.
    Notes: Catalysts of the ZIEGLER-NATTA type have been applied widely for the synthesis of olefin block copolymers. More recently the preparation of olefin block polymers with vinyl monomers has been achieved by converting the “living” chains from an anionic polymerization into free radicals in the presence of peroxides to allow the formation of blocks. The yield of block copolymers does not exceed a few per cent since it is well known now that the number of “living” chains is extremely low. It has been found that the incorporation of a suitable chain transfer agent such as diethyl zinc during the coordinative polymerization provides a new way to increase considerably the “active” centers which are capable to initiate, in the presence of a radical initiator, the polymerization of the vinyl monomers giving high yield of block copolymers containing variable amounts of the vinyl polymers. Moreover, under certain conditions, it is possible to synthesize either block, or block and graft, or graft copolymers only. The formation of the corresponding homopolymers can be avoided to a large extent. In order to illustrate this new technique with an example, we describe here only the synthesis of polyethylene/polymethylmethacrylate, block and/or graft copolymers, although-a-large variety of other copolymers has been studied.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1970.021370123
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  • 7
    Electronic Resource
    Electronic Resource
    Computation of the ESR. Coupling Constants of the [16]Annulene Radical Anion; Theoretical and Experimental Reinvestigation of the Excited States of [16]Annulene and its Mono- and Dinegative Ions (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 618-629 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The problem of assigning the two small ESR. coupling constants of the [16]annulene radical anion to the two sets of four equivalent outer and inner ring protons is treated by three different semiempirical MO methods. All three methods indicate that the smaller coupling constant (0.743 Gauss) should be assigned to the inner protons, and the larger one (0.963 Gauss) to the outer ones. The electronic spectra of [16]annulene, its radical anion, and its dianion have been remeasured. Especially interesting was the detection of a symmetry-forbidden band of the radical anion at 1473 nm (6789 cm-1, logε 2.57). The spectra are discussed in terms of different MO models.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19800630309
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  • 8
    Electronic Resource
    Electronic Resource
    Structure, Synthesis, and Properties of Some Persubstituted 1,2-Dintroethanes. In Quest of Nitrocyclopropyl-Anion Derivatives (1982)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 65 (1982), S. 137-161 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Attempts to deprotonate nitrocyclopropane led to solutions which showed strong ESR. signals (Fig. 1)and from which 1-nitro- l′-nitroso-bicyclopropyl (3) and 1,1′-dinitro-bicyclopropyl (2) were isolated. The activation energy for rotation about the central C, C-bond of 2 is estimated to be about 12 kcal/mol (1 H-NMR. spectra in Fig. 2). In contrast, the oven-chain analogue 2,3-dimethyl-2,3-dinitrobutane (1) shows a methyl singlet down to -70° C. Low-temperature X-ray analyses of 1, 2, 3, and also of 1,1′-dinitro-bicyclobutyl (4) show that all four molecules have gauche-conformations but reveal striking structural differences between the openchain and the cyclic derivatives (Fig. 4-6): the central C, C-bond is long in 1 (1.575 Å), short in 2 (1.479 Å); the C, N-bonds are long in 1 (1.549 Å), short in 2 (1.488 Å); the orientation of the nitro groups is bisected in 2 and perpendicular in 1. The crystal structure of the nitro-nitroso compound 3 is isomorphous with that of the dinitro compound 2 and thus disordered (Fig. 15-16). The effect of the nitro group as π-electron acceptor on the molecular conformations and bond lengths is discussed. From analysis of the anisotropic vibrational parameters of 2 the root-mean-square librational amplitude of the nitro groups about their C, N-bonds is estimated to be about 5.8° at 95 K, corresponding to a rotational barrier of about 9 kcal/mol, i. e. the same order of magnitude as the NMR. estimate of about 12 kcal/mol for C, C-rotation.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19820650114
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  • 9
    Electronic Resource
    Electronic Resource
    Quantitative Line-Shape Analysis of Temperature- and Concentration-Dependent 13C-NMR Spectra of 6Li- and 13C-Labelled Organolithium Compounds. Kinetic and Thermodynamic Data for Exchange Processes in Dibromomethyllithium, (Phenylthio)methyllithium, and Butyllithium (1985)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 68 (1985), S. 1848-1862 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Using the ‘permutation of indices’ method proposed by Kaplan and Fraenkel, we could formulate the density-matrix equations required to fit the temperature-dependent 13C-NMR spectra observed with the title compounds. For 6Li13CHBr2 (1) and 6Li13CH2SC6H5 (2) an exchange mechanism is proposed by which monomers interchange C- and Li-atoms via a non-observed dimeric intermediate; the activation parameters of these intermolecular dynamic processes have been found to be ΔH≠ = 10.2 kcal/mol, ΔS≠ = 13.7 cal/mol·K for 1 and ΔH≠ = 11.1 kcal/mol, ΔS≠ = 20.6 cal/mol·K for 2 ((D8)THF as solvent). In the case of (6Li)butyllithium (3), the observed low-temperature spectra indicate that dimeric (3b) and tetrameric (3a) species are in dynamic equilibrium interchanging the C3H713CH2 groups (and THF molecules) bonded to the 6Li-atoms. The relative concentrations of the dimer and of the tetramer have been determined by peak integration or by line-shape fitting; the ‘pseudo’- equilibrium constant, defined by K′eq = [3b]2/[3a], was found to be 2.6·10-2 mol/1 (at -88°) and corresponds to ΔGR (-88°) = 2 ΔG°f(3b) - ΔG°f(3a) = 1.34 kcal/mol. The activation parameters of the dynamic process responsible for the exchange were estimated as ΔH≠ = 3.78 kcal/mol and ΔS≠ = -31.3 cal/mol·K. Tentative interpretation of the thermodynamic and kinetic parameters is given.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19850680707
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  • 10
    Electronic Resource
    Electronic Resource
    π-Bond Configurations, Conformations, and Dynamic Behaviour of Benzo[c]octalene and Dibenzo[c,j]octalene (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2411-2425 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The π-bond configurations, the conformations, and the dynamic behaviour of dibenzo [c,j]octalene (2) and of benzo [c]octalene (3) have been investigated by 13C-NMR. spectroscopy at different temperatures. Dibenzooctalene was found to present π-bond fixation in the octalene unit as in 2b; with this π-bond fixation the molecule is not planar and takes two different conformations which are rapidly interconverted by inversion of one cyclooctatetraene ring. Monobenzooctalene (3) also presents π-bond fixation in the octalene unit but exists as two valence isomers, 3b and 3c. Isomer 3c dominates the dynamic equilibrium. With this π-bond configuration, the molecule is chiral but undergoes several isodynamic processes, namely inversion of the cyclooctatriene and/or of the cyclooctatetraene ring. The valence isomer 3b can have two different conformations which are rapidly interconverted by inversion of one cyclooctatetraene ring. The interconversion 3c ⇌ 3b implies the occurrence of a π-bond shift process; this process affects the 13C-NMR. lineshape above 50°.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19800630834
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