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  • 1
    Electronic Resource
    Electronic Resource
    β-Turns in bridged proline-containing cyclic peptide models (1987)
    New York : Wiley-Blackwell
    Biopolymers 26 (1987), S. 1555-1572 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis, CD, ir spectroscopic, and conformational studies of a series of bridged cyclic peptides of the general formula, cyclo[NH-(CH2)n-CO-Gly-Pro-Y-Gly] (2a-d, Y = Gly or Ser(OBut), n = 4 or 2) is reported. As indicated by difference nuclear Overhauser enhancement and Fourier transform ir experiments, the tetrapeptide sequence of cyclo[NH-(CH2)4-CO-Gly-Pro-Gly-Gly] (2a) and cyclo[NH-(CH2)2-CO-Gly-Pro-Gly-Gly] (2b) adopts a 1 ← 4 hydrogenbonded type II β-turn conformation in solution, while cyclo[NH-(CH2)4-CO-Gly-Pro-Ser(OBut) -Gly] (2c) features a type I β-turn, fixed by 1 ← 4 and Oγ … NH intramolecular H bonds. In aqueous solution 2a and 2c show class B and class C CD spectra, respectively. This is the first case reported of a typical class C CD pattern in aqueous solution for a conformationally mobile system having a type I β-turn. Based on the comparison of the band intensities of the bridged models with those of linear and cyclic model systems reported earlier, a set of subspectra with reduced band intensities is suggested for use in the CD analysis of the conformation of polypeptides in solution.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360260908
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  • 2
    Electronic Resource
    Electronic Resource
    High resolution NMR spectroscopy of heteroaromatic cations. I. 13C—1H coupling constants in the pyridinium cation (1980)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 14 (1980), S. 98-102 
    Details
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: High-resolution 1H—{14N} and proton-coupled natural-abundance 13C—{14N} double resonance spectra have been recorded for pyridinium tetrafluoroborate dissolved in CD3CN. Iterative analysis of these spectra has provided the accurate values and relative signs of all possible long-range 13C - 1H coupling constants. These are compared with the respective values in pyridine and pyridine-N-oxide and discussed in terms of the relationship with the electronegativity of the N-substituent. Experimental conditions allowing the observation of well-resolved proton-coupled 13C NMR spectra of charged heteroaromatics are also presented.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1270140205
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  • 3
    Electronic Resource
    Electronic Resource
    Determination of the 1H - 31P coupling parameters in triphenylphosphine (1974)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 6 (1974), S. 60-61 
    Details
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: From the single and double resonance 1H NMR spectra of triphenylphosphine, magnitudes and relative signs of the proton-proton and proton-phosphorus spin coupling constants were calculated. The values of these parameters were found to be nearly equal to those of the respective 1H - 1H couplings in benzene. Results show that inter-ring proton-proton couplings are negligibly small.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1270060116
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  • 4
    Electronic Resource
    Electronic Resource
    Proton-proton coupling constants in the unsubstituted pyrylium cation (1973)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 5 (1973), S. 251-252 
    Details
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An iterative analysis of the PMR spectrum of the title compound was performed and the calculated values of spectral parameters, relative chemical shifts, proton-proton and direct carbon-proton couplings are compared with those of pyridine.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1270050512
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  • 5
    Electronic Resource
    Electronic Resource
    Carbon-13 NMR spectra of fusicoccin and its derivatives (1975)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 7 (1975), S. 137-142 
    Details
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 13C NMR spectra of fusicoccin, some of its cometabolites and derivatives were studied. Using standard Fourier transform techniques, T1 relaxation time measurements and lanthanide shift reagents, the resonances of individual carbon-13 nuclei were assigned.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1270070306
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  • 6
    Electronic Resource
    Electronic Resource
    High resolution NMR spectroscopy of heteroaromatic cations. II - pyrylium, thiapyrylium and seleninium cationsFor Part I, see Ref. 1. (1981)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 16 (1981), S. 148-155 
    Details
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: High resolution 1H, proton coupled 13C and broad-band decoupled 13C—{1H} spectra have been recorded for pyrylium, thiapyrylium and seleninium tetrafluoroborates in CD3CN. Analysis of these spectra has provided accurate values and relative signs of all 1H,1H and 13C,1H coupling constants, as well as the magnitudes of all one- and three-bond 13C,13C couplings observable in naturally occurring doubly-labelled isotopomers. For the seleninium cation, the magnitudes and relative signs of all 77Se,1H and 77Se,13C coupling constants were also obtained. The chemical shifts and coupling data are compared, on a qualitative basis, with existing theoretical predictions.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1270160218
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  • 7
    Electronic Resource
    Electronic Resource
    Kondensierte Azoliumsalze, IVAls III. Mitteilung gilt: A. Messmer u. A. Gelléri, Angew. Chem. 79, 272 (1967).. Synthese von 1,3-Diaryl-s-triazolo[4,3-a]pyridiniumsalzen und deren Benzologen (1976)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 318 (1976), S. 881-890 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Fused Azolium Salts. IV. Synthesis of 1,3-Diaryl-s-triazolo[4,3-a]pyridinium Salts and their BenzologuesIn presence of carbon tetrachloride aroylchloride-arylhydrazones 1a-i give 1,3-diaryl-s-triazolo[4,3-a]pyridinium salts 5a-i with pyridine directly. Using quinoline or isoquinoline as a reagent, s-triazolo[4,3-a]quinolinium 6a-i and s-triazolo[3,4-a]isoquinolinium salts 7a-i have been prepared. The spectral data of the new salts are also discussed.
    Notes: 1,3-Diaryl-s-triazolo[4,3-a]pyridiniumsalze 5 entstehen aus Pyridin und Aroylchlorid-arylhydrazonen 1 in Anwesenheit von CCl4 in einem Schritt. Die Reaktion bewährt sich auch zur Darstellung von s-Triazolo[4,3-a]chinolinium- und s-Triazolo[3,4-a]isochinoliniumsalzen 6, 7. Es werden die Charakteristika der Spektren besprochen.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19763180602
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