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  • 1
    Electronic Resource
    Electronic Resource
    Synthese und 1H-NMR-spektroskopische Untersuchungen neuer Curcuminanaloga (1992)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 334 (1992), S. 696-700 
    Details
    ISSN: 0941-1216
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis and 1H-NMR Spectroscopic Investigations of New Curcumin AnalogaThe synthesis of numerous symmetric and non-symmetric curcumin(hetero) analoga (1-3) systematic variation of the conjugated chain and substituents is described. The structure of most compounds is confirmed by 1H-n.m.r.-spectroscopy. All compounds show E-configuration. Conjugation and tautomerism are discussed based on spectroscopic data.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19923340810
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  • 2
    Electronic Resource
    Electronic Resource
    Eine 2D-INEPT-Variante zur Detektierung wenig empfindlicher Kerne (1992)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 334 (1992), S. 181-182 
    Details
    ISSN: 0941-1216
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Detection of Less Sensitive Nuclei by Means of a Special 2D INEPT Version
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19923340216
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  • 3
    Electronic Resource
    Electronic Resource
    Zur Zuordnung der 13C-chemischen Verschiebung substituierter Naphthaline aus Ladungsdichten mit Hilfe neuronaler Netze (1995)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 337 (1995), S. 504-507 
    Details
    ISSN: 0941-1216
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The Assignment of the 13C-NMR Chemical Shifts of Substituted Naphthalenes from Charge Density with an Artificial Neural NetworkNeuronal networks are a new possibility to work with blurred data and informations. In this article, the use of a multilayer network with backpropagation of errors for the prediction of the 13C-chemical shifts of a series of substituted naphthalenes from the σ- and π- charge density of the corresponding carbon atoms (calculated by means of the PIMM program) will be described. The average uncertainty for the estimation of the 13C-chemical shifts of monosubstituted naphthalenes is only 2.1 ppm, for naphthalenes with more than one substituent about 4 ppm.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.199533701106
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  • 4
    Electronic Resource
    Electronic Resource
    Quinoxalines. IX. Reaction of 2-(Halogenomethyl)-quinoxalines and -quinoline with hydroxybenzoic acids and their esters (1997)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 339 (1997), S. 714-720 
    Details
    ISSN: 0941-1216
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In the presence of a base the title compounds react to products with ether structure (4, 6), or with ester structure (3), or to structure 5 containing both functionalities in dependence on the mole ratio of the starting substances, on reaction conditions and on the substituent patterns in the hydroxybenzoic acid component.Under the influence of alkali hydroxide the m- and p-substituted compounds (6e-g) are saponified to the alkali salts of the carboxylic acid (4b, c). The o-substituted compounds (6a-d), however, are cyclized to the benzo[b]furanylquinoxalines (8). 8a, d are also obtained by thermal water elimination of the carboxylic acids 4a, d. The red-coloured benzofuranols 8 react with acetic anhydride and benzoyl-chloride/pyridine, resp., to the weakly yellow esters 9.The stucture of the products 8 and 9 is studied by UVVIS derivative spectroscopy, by theoretical calculation of the dihedral angles and by 1H and 13C NMR spectroscopy. The 1H and 13C chemical shifts are completely assigned. The quinoxalines 8a-c and the quinoline 8d only exist in the hydroxy form.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.199733901130
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  • 5
    Electronic Resource
    Electronic Resource
    Quantitative Bestimmung geringer Phosphatmengen in Trinatrium-Phosphonoformiat mittels 31P-NMR-Spektroskopie (1994)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 336 (1994), S. 340-342 
    Details
    ISSN: 0941-1216
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Determination of Small Quantities of Residue Phosphate in Tris-Sodium Phosphane Formiate by Means of 31P NMR SpectroscopyThe concentration of residue phosphate in tris-sodium-phosphon-formiate (TPF·6H2O) water solutions has been determined via comparing integration of the 31P n.m.r. signal of the residue phosphate and one of the 31C NMR satellites of the TPF·6H2O 31P n.m.r. signal. The 31P n.m.r. spectra have been obtained in inverse gated detection mode; statistical methods of validation prove the certainty of the phosphate concentrations obtained to be excellent and strongly recommend the quantitative method employed for the detection of concentrations down to 0,1%.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19943360412
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  • 6
    Electronic Resource
    Electronic Resource
    1H-NMR-Spektroskopische Untersuchungen an isomeren Alkendiinen (1976)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 8 (1976), S. 246-251 
    Details
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 1H NMR spectra of several aliphatic and phenyl substituted alkenediynes have been obtained. Chemical shifts and coupling constants of these compounds are discussed in conjunction with some compounds described in the literature. Chemical shifts of the protons from isomeric alkenediynes R—C≡C—C≡C—CH=CH2, R—CH=CH—C≡C—C≡CH and R—CH=CH—C≡C—C≡C—CH3 (R = H, alkyl, C6H5, C6H4OCH3-p) are well correlated with cis/trans-isomerism and electronic effects of substituents at the C=C bond. The coupling constants were found to be only slightly dependent on the substitution at the double bond. We could resolve couplings over a maximum of eight bonds in the alkenediyne system.
    Notes: Die 1H-NMR-Spektren einer Reihe aliphatisch und phenylsubstituierter Alkendiine werden vorgestellt und, unter Berücksichtigung einiger literaturbekannter Verbindungen, chemische Verschiebungen und Kopplungskonstanten diskutiert.Die chemischen Verschiebungen der Protonen der untersuchten isomeren Alkendiine R—C≡C—C≡C—CH=CH2, R—CH=CH—C≡C—C≡CH und R—CH=CH—C≡C—C≡C—CH3 (R = H, Alkyl, C6H5, C6H4OCH3-p,) lassen sich hinsichtlich cis/trans-Isomerie und Substitution an der Doppelbindung befriedigend mit elektronischen Effekten und molekularen Magnetfeldern der Mehrfachbindungen erklären. Die Kopplungs-konstanten erweisen sich als kaum abhängig von der Substitution an der Doppelbindung. Über die Diacetylengruppierung hinweg können Kopplungen über maximal acht Bindungen beobachtet werden.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1270080506
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  • 7
    Electronic Resource
    Electronic Resource
    NMR-Untersuchungen an Dicyclopentadienderivaten: I - 1H-NMR: Anwendung von paramagnetischen Verschiebungsreagenzien (Eu(fod)3) zur Vereinfachung der Spektren exo/endo-isomerer Diole (1976)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 8 (1976), S. 261-265 
    Details
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The determination of the stereochemistry of a series of exo/endo-isomeric dihydro- and tetrahydro-dicyclopentadiene-9.10-diols (exo/exo or endo/endo), using Eu(fod)3 for separation of the signals in their 1H n.m.r. spectra, is discussed in detail. The paramagnetic shift values ΔEu determined for half-molar ratios Eu(fod)3/diol allow an unambiguous stereochemical assignment of the diols with regard to exo/endo isomerism. The ΔEu quantities are correlated with the distance Hi…O-atom (Ri).
    Notes: Die Bestimmung der Stereochemie einer Reihe exo/endo-isomerer 9.10-Dihydro- bzw. Tetrahydrodicyclopentadien-9.10-diole (exo/exo bzw. endo/endo) unter Verwendung von Eu(fod)3 zur Auftrennung ihrer 1H-NMR-Spektren wird beschrieben. Die für halbmolares Verhältnis Eu(fod)3/Diol bestimmten Verschiebungswerte ΔEu gestatten dabei eine eindeutige stereochemische Zuordnung der Verbindungen. Die ΔEu-Werte werden mit dem Abstand Hi…O-Atom (Ri) korreliert.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1270080509
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  • 8
    Electronic Resource
    Electronic Resource
    1H- und 13C-NMR-untersuchungen an dibromoxabicyclo[n.2.1]alkanen (1977)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 9 (1977), S. 105-107 
    Details
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The 1H n.m.r. spectra of some dibromooxabicyclo[n.2.1]alkanes are discussed for the determination of the configuration and conformation. The 13C n.m.r. spectra confirm the observed stereochemistry. With increasing ring size the 13C n.m.r. chemical shifts of the hetero atom substituted C-atoms C-1 and C-2 move steadily to lower fields.
    Notes: Die 1H-NMR-Spektren einer Reihe von Dibromoxabicyclo[n.2.1]alkanen werden zur Bestimmung der Konfiguration und Konformation herangezogen. Die 13C-NMR-Spektren bestätigen die ermittelte Stereochemie. Mit zunehmender Ringgröße verlagern sich die 13C-chemischen Verschiebungen der heteroatomsubstituierten C-Atome kontinuierlich nach niederem Feld.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1270090211
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  • 9
    Electronic Resource
    Electronic Resource
    Konformationsuntersuchungen mit Hilfe der 13C-NMR-Spektroskopie. III. 13C-NMR-spektroskopische Verschiebungen durch sterisch gehinderte Methylgruppen (1978)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 11 (1978), S. 561-564 
    Details
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The 13C NMR chemical shifts of some cyclohexane derivatives containing 1,3-diaxial methyl groups are assigned. The resonance signals of the methyl carbon atoms 1 and 3 in these compounds are shifted on average by 4.5 ppm to lower field (δ-effect). The ring carbon atoms 1 and 3 also show shifts to lower field, averaging 0.7 ppm (γ-effect). In open-chain hydrocarbons, analogous shift effects are observed when the investigated compounds have the geometry of the gPgM conformer of n-pentane.
    Notes: Die 13C-NMR-Spektren einer Reihe von Cyclohexanen mit 1,3-diaxialen Methylgruppen wurden bestimmt. Die Resonanzsignale der Methyl-Kohlenstoffatome 1 und 3 sind in diesen Verbindungen um durchschnittlich 4,5 ppm nach tieferem Feld verschoben (δ-Effekt). Auch die Ringkohlenstoffatome 1 und 3 zeigen Verschiebungen um durchschnittlich 0,7 ppm nach tieferem Feld (γ-Effekt). In offenkettigen Kohlenwasser-stoffen werden analoge Verschiebungseffekte beobachtet, wenn in den betreffenden Verbindungen die Geometrie des gPgM-Konformeren des n-Pentans vorkommt.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1270111107
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  • 10
    Electronic Resource
    Electronic Resource
    d-NMR-Untersuchungen der behinderten Rotation am N—C-(X)-Bindungsinkrement. VIII. Metallkomplexverbindungen von 1,1-Diäthyl-3-benzoylthio- und selenoharnstoffVII. Mitteilung: E. Kleinpeter, R. Widera u. M. Mühlstädt, Z. Chem., 17, 298 (1977). (1977)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 437 (1977), S. 282-288 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: d-N.M.R. Studies of Hindered Rotation on N—C(X) Bond Increment. VIII. Metal Complexes of 1,1-Diethyl-3-benzoylthio- and selenoureaThe coordination of 1,1-Diethyl-3-benzoylthiourea (debtu) and 1,1-Diethyl-3-benzoylselenourea (debsu) to a metal ion leads both with subgroup elements (Ni(II), Pd(II), Co(III), Zn(II), Cu(I)) and with main group elements (Pb(II), Tl(I)) to an increase of the free enthalpy of activation of the rotational process about the terminal N—C(X) bond. The order of the increase is with debtu: Ni(II) 〉 Pb(II) 〉 Pd(II) 〉 Co(III) 〉 Tl(I) and with debsu: Ni(II) 〉 Zn(II) 〉 Pd(II) 〉 Co(III). A decrease of the barrier of rotation was observed with Tl(debsu) only, which is dimeric in benzene solution. The characteristic IR-data of the ligand debtu and its Pd(II)-, Ni(II)-, and Tl(I)-complexes, and of the Cu(debtu)3Cl complex are given. The results are discussed.
    Notes: Die Koordination der Liganden 1,1-Diäthyl-3-benzoylthioharnstoff (debtu) und 1,1-Diäthyl-3-benzoylselenoharnstoff (debsu) an ein Metallatom führt sowohl bei Nebengruppenelementen (Ni(II), Pd(II), Co(III), Zn(II), Cu(I)) als auch bei Hauptgruppenelementen (Pb(II), Tl(I)) zur Erhöhung der freien Aktivierungsenthalpie ΔGc≠ der Rotation um die N—C(X)-Bindung. Die Reihenfolge der Erhöhung ist beim debtu: Ni(II) 〉 Pb(II) 〉 Pd(II) 〉 Co(III) 〉 Tl(I) und beim debsu: Ni(II) 〉 Zn(II) 〉 Pd(II) 〉 Co(III). Nur beim Tl(debsu) beobachtet man eine Erniedrigung der Rotationsbarriere. Es liegt in benzolischer Lösung dimer vor. Die charakteristischen IR-Daten des Liganden debtu und seiner Pd(II)-, Ni(II)- und Tl(I)-Komplexe, sowie die des Cu(debtu)3Cl werden angegeben. Die erhaltenen Ergebnisse werden diskutiert.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19774370141
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