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  • 1
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 7 (1975), S. 504-507 
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The proton NMR spectrum of cinnoline has been measured at high field (250 MHz) and analysed as an H-8-de-coupled ABCXY and H-4-decoupled ABCX system. Inter-ring H—H couplings have been determined and discussed in relation to theoretical values obtained using INDO calculations.
    Additional Material: 2 Ill.
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  • 2
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 8 (1976), S. 457-460 
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 13C n.m.r. spectra are reported for 1,3-indandione, phthalic anhydride, thiophthalic anhydride, and phthalimide in chloroform-d solution. The 13C chemical shifts have also been calculated by means of Pople's perturbation theory using CNDO/S wave functions; the agreement between theoretical and experimental values is improved when an empirical charge-dependent term is added to the calculated diamagnetic and paramagneitc contributions.
    Additional Material: 1 Ill.
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  • 3
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 9 (1977), S. 401-403 
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 13C n.m.r. spectra are reported for 1,2-indandione, coumarandione and thionaphthenequinone in CDCl3 solution and for isatin in dimethyl sulphoxide solution. The chemical shifts are assigned and discussed in connection with the influence of the heteroatom on the dicarbonyl group and the aromatic ring. The 13C shieldings have also been calculated by means of Pople's perturbation theory using CNDO/S wave functions.
    Additional Material: 2 Tab.
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  • 4
    ISSN: 0749-1581
    Keywords: N-Propynylnormetazocine ; Conformation ; Relaxation times ; Motional analysis ; Molecular Modelling ; 1H and 13NMR spectra ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The analysis of high-frequency 1H and 13C NMR spectra and both 1H—1H homonuclear and 1H—13C heteronuclear chemical shift correlation experiments indicate that N-propynlnormetazocine (NPMH+) is configurationally heterogeneous in solution, with the N-equatorial isomer being more populated than the N-axial isomer. The experimental proton-proton coupling constants measured for both diastereoisomers were in agreement with the calculated values for a chair conformation of the piperidine ring. AM1 and MM2 theoretical calculations both indicated the chair conformation as that preferred by the piperidine ring, and the N-equatorial isomer as being energetically favoured with respect to the N-axial form. The best fit of the 13C T1 relaxation time data and the related motional analysis of NPMH+ was carried out using the anisotropic model of reorientation with superimposed internal motion. The results showed an increase of the rotational anisotropy of the molecule on passing from the gas phase to the solution state.
    Additional Material: 6 Ill.
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  • 5
    ISSN: 0749-1581
    Keywords: Cyclazocine ; 13CNMR ; Relaxation times ; Reorientational dynamics ; Internal mobility ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The motional behaviour of the mixed agonist-antagonist opioid narcotic cyclazocine (2-cyclopropylmethyl-2′-hydroxy-5,9-dimethyl-6,7-benzomorphan) as a cationic species (CLZH +) was analysed by 13C NMR spin-lattice relaxation times (T1). Both AM1 and MM2 theoretical calculations were performed to predict the preferred conformations and torsional energetics of CLZH+ in the vapour phase. The analysis of the experimental T1 data (in aqueous solution) was performed by using an analytical model to describe the overall and internal motions of the molecule. The best fit of the relaxation times allowed the detection, in the liquid phase, of effective solute-solvent interactions and the fully anisotropic diffusive process of the molecule. The motional parameters obtained indicated an increased retational anisotropy of CLZH+ on passing from the gas phase to the solution state. Different activation energies arising from separate solvation effects were found for the motion of the 10-Me and 11-Me groups. The fitted energies and transition energies matrix relative to the internal motion of the N-cyclopropylmethyl group indicated that the preferred conformational states are not isolated and that the overall and internal motions are of the same order of magnitude.
    Additional Material: 2 Ill.
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  • 6
    ISSN: 0749-1581
    Keywords: Arsenolipid ; 2D NMR ; 1H and 13C NMR ; 31P arsenophosphonolipid ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 1H (500 MHz), 13C (300 MHz) and 31P (202 MHz) NMR spectra of rac-2,3-bis(palmitoyloxy)propyl(2-trimethylarsonioethyl)phosphonate were recorded in CDCl3 (3 M) solution. Homonuclear 1H-1H and heteronuclear 13C-1H chemical shift correlation experiments (COSY) were performed. All resonances were assigned. The shifts of the arsenic-containing phosphonolipid were compared with the shifts of the N-containing phospholipids. The most significant shift differences were found for the groups directly bonded to arsenic. Spectral evidence was indicative of free rotation about the —CH2 —CH2 —bond in the arsenocholine fragment.
    Additional Material: 5 Ill.
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  • 7
    ISSN: 0749-1581
    Keywords: Cognition activator drugs ; Inclusion complexes ; Cyclodextrins ; NMR-ROESY ; Molecular modelling ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The structural features of the inclusion complexes of cyclodextrins (CDs) with the chiral cognition activator drug (±)9-[(phenylmethyl)amino]-1,2,3,4-tetrahydroacridin-1-ol maleate (suronacrine maleate, HP-128) were studied using both high-resolution 1H NMR spectroscopy and molecular modelling methods. The partial inclusion of the guest from the secondary hydroxyl side of α-CD was demonstrated in aqueous solution, in addition to a higher degree of penetration into the cavity of β-CD from the same side. NMR-ROESY experiments allowed the unambiguous location of the benzylic ring of the guest inside the β-CD cavity. The formation of diastereoisomeric pairs was demonstrated by the duplication of the benzylic proton signals. Molecular mechanics calculations were used to complement the NMR analysis. Molecular modelling procedures (MacroModel interactive computer program) allowed the prediction of the most stable structures of the complexes, and showed that specific site interactions, provided by hydrogen bond formation, are capable of differentiating the diastereoisomeric intramolecular inclusion complexes according to available experimental NMR data.
    Additional Material: 5 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 26 (1988), S. 693-700 
    ISSN: 0749-1581
    Keywords: 1H NMR ; 13C NMR ; Benzomorphans ; 2D NMR ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The high-frequency 1 and 13C NMR spectra (at 500 and 75.47 MHz, respectively) of metazocine (MTZ) fumarate, pentazocine (PTZ) and cyclazocine (CLZ) hydrochlorides in 2H2O solution were recorded and analysed with the aid of both homonuclear 1H—1H and heteronuclear 13C—1H chemical shift correlation experiments. At neutral pH all compounds were found to be configurationally heterogeneous, with the N-equatorial isomer more populated than the N-axial isomer (ratio ca 80:20). The low-intensity peaks of the superimposed spectral pattern of the less populated isomer were also assigned on correlative grounds in both the 1H and 13C NMR spectra of MTZ, PTZ and CLZ. The occurrence of distinct spectra for the two configurational isomers was diagnostic of a ‘slow’ exchange process on the NMR time-scale at the field frequencies employed for the experiments, thus suggesting a high-energy barrier to interconversion. The experimental proton-proton coupling constants measured for the N-equatorial form of MTZ, PTZ and CLZ were consistent with a chair conformation of the piperdinic ring in all compounds. The distinct relative agonist-antagonist potencies of the drugs investigated could therefore not be correlated with the above-described configurational and conformational features.
    Additional Material: 6 Ill.
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