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  • 1
    Electronic Resource
    Electronic Resource
    Reinvestigation of E/Z diastereomerism in imidates (1974)
    s.l. : American Chemical Society
    Journal of the American Chemical Society 96 (1974), S. 2259-2260 
    Details
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ja00814a050
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  • 2
    Electronic Resource
    Electronic Resource
    Gas chromatography/mass spectrometry and gas chromatography/mass spectrometry/mass spectrometry of methyl ester/methoxime/trimethylsilyl ether derivatives of thromboxanes (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 139-142 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Electron impact mass spectra of methyl ester/methoxime/trimethylsilyl ether derivatives of thromboxane B2 (TxB2) and 2,3-dinor-TxB2 and methyl ester/trimethylsilyl ether derivative of 11-dehydro-TxB2 are presented. Additionally, the derivatives of (2H4)-thromboxanes and methyl ester (2H3)-methoxime/trimethylsilyl ether derivatives of TxB2 and 2,3-dinor-TxB2 and (2H3)-methyl ester/trimethylsilyl ether derivative of 11-dehydro-TxB2 were investigated. Collision-induced dissociation mass spectra of the most intense parent ion in the high-mass region were taken. Collisionally activated decomposition mass spectra of the [C(12)-C(20)]+ ion of TxB2 and 2,3-dinor-TxB2 show an intense but not specific daughter ion, whereas the collison-induced dissociation mass spectrum of the [M - (C(16)-C(20)]+ ion of 11-dehydro-TxB2 results in the formation of numerous daughter ions.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200150304
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  • 3
    Electronic Resource
    Electronic Resource
    Negative ion chemical ionization gas chromatography/mass spectrometry and gas chromatography/tandem mass spectrometry of prostanoid pentafluorobenzyl ester/methoxime/trimethylsilyl ether derivatives (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 143-151 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Negative ion chemical ionization mass spectra of prostaglandin F2α, prostaglandin E2, prostaglandin D2, 6-oxo-prostaglandin F1α, 2,3-dinor-6-oxo-prostaglandin F1α, thromboxane B2, 2,3-dinor-thromboxane B2, and 11-dehydro-thromboxane B2 pentafluorobenzyl ester (PFB)/methoxime/trimethylsilyl ether derivatives are presented. Collisionally activated decomposition mass spectra of the [M - PFB]- ions at collision energies of 8-24 eV and argon collision gas pressures of 1-2 mTorr almost show only fragmentation of trimethylsilanol, (CH3)2Si=CHOH, (CH3)2Si=CH2 and methanol whereas, except for carbon dioxide loss, only few low-intensity fragments from the carbon skeleton of the prostanoids are observed.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200150305
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  • 4
    Electronic Resource
    Electronic Resource
    Gas chromatography/mass spectrometry and gas chromatography/tandem mass spectrometry of methyl ester/methoxime/trimethylsilyl ether derivatives of prostaglandins (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 129-138 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Electron impact mass spectra of methyl ester/trimethylsilyl ether derivatives of prostaglandin F2α and methyl ester/methoxime/trimethylsilyl ether derivatives of prostaglandin E2, prostaglandin D2, 6-oxo-prostaglandin F1α and 2,3-dinor-6-oxo-prostaglandin F1α are presented. Most of the prostaglandins studied have additionally been 2H-labelled at different sites in order to assign the corresponding fragment ions. Collisionally activated decomposition mass spectra of the most intense parent ions in the high-mass region were taken. High-intensity, prostaglandin-characteristic daughter fragments will allow a reliable quantification of prostaglandins in biological fluids and a reduction of sample clean-up.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200150303
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  • 5
    Electronic Resource
    Electronic Resource
    Determination of prostaglandin E1 and its main plasma metabolites 15-keto-prostaglandin E0 and prostaglandin E0 by gas chromatography/negative ion chemical ionization triple-stage quadrupole mass spectrometry (1994)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 23 (1994), S. 165-170 
    Details
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Prostaglandin E1 (PGE1), 15-keto-PGE0 and PGE0 in plasma were determined in an isotope dilution assay by gas chromatography/triple-stage quadrupole mass spectrometry. After addition of deuterated internal standards, the prostaglandins were extracted by a solid-phase cartridge and derivatized to the pentafluorobenzyl ester methoxime. The samples were purified by thin-layer chromatography, converted to the trimethylsilyl ethers and quantified by gas chromatography/triple-stage quadrupole mass spectrometry. The parent ions in the negative ion chemical ionization mode were [M — pentafluorobenzyl]- ([P]-), the daughter ions used for quantification were [P — (CH3)3SiOH]- (PGE0 and 15-keto-PGE0) and [P — 2 (CH3)3SiOH]- (PGE1), respectively. Plasma concentrations in healthy subjects were at about 1-3 pg ml-1 for PGE1 and PGE0 and 2-15 pg ml-1 for 15-keto-PGE0. After infusion of 60 μg PGE1 in 2 h, the concentrations in plasma were 3-10 pg ml-1 for PGE1, 8-17 pg ml-1 for PGE0 and 115-205 pg ml-1 for 15-keto-PGE0.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200230308
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  • 6
    Electronic Resource
    Electronic Resource
    Alkylierungsreaktionen an Thioamiden, VI. Isolierung von E- und Z-Thioimidsäureestern (1980)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 171-182 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Alkylation Reactions of Thioamides, VI. Isolation of E- and Z-ThioimidatesIn a sequence of stereospecific reactions the pure geometric isomers of ortho-substituted methyl thiobenzimidates 3 were prepared from the appropriate thiobenzamides 1. E/Z ratios and barriers to isomerization were determined by means of 1H NMR measurements.
    Notes: In einer Sequenz stereospezifischer Reaktionen wurden die reinen geometrischen Isomeren ortho-substituierter Thiobenzimidsäure-methylester 3 aus den entsprechenden Thiobenzamiden 1 dargestellt. Die E/Z-Verhältnisse und Isomerisierungsbarrieren wurden durch 1H-NMR-Messungen bestimmt.
    Additional Material: 8 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19801130118
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  • 7
    Electronic Resource
    Electronic Resource
    Darstellung und Untersuchung der Isomerisierung von N-(Arylthio)kohlensäureimidester-Derivaten (1976)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 109 (1976), S. 3129-3135 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation and Investigations on the Isomerization ofN-Arylthio Iminocarbonate DerivativesThe N-sulfenylation of iminocarbonates, monothioiminocarbonates, and dithioiminocarbonates with sulfenylchlorides gives the thiooxime derivatives 4-6, for which barriers to isomerization (ΔG≠ 65.7-73.6kJ/mol) were determined by means of D n. m. r. spectroscopy.
    Notes: Die N-Sulfenylierung von Kohlensäureimidestern, Monothiokohlensäureimidestern und Dithiokohlensäureimidestern 1-3 mit Sulfenylchloriden liefert die Thiooxim-Derivate 4-6, deren Isomerisierungsbarrieren (ΔG≠ 65.7-73.6kJ/mol) mit Hilfe der D-NMR-Spektroskopie ermittelt wurden.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19761090918
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  • 8
    Electronic Resource
    Electronic Resource
    Alkylierungsreaktionen an Thioamiden, III: Untersuchungen zur Rotation um die Imidium-Doppelbindung bei Thioimidiumsäureester-Salzen (1976)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 109 (1976), S. 947-955 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Alkylation Reactions of Thioamides, III: Investigations of the Rotation about the Imidium Double bond in Thioimidium Ester SaltsThe barriers to rotation about the CN double bond in thioimidium ester salts 1-15 were determined by means of kinetic and dynamic n. m. r. measurements. Depending on steric and electronic effects ΔG≠ values of 89.9 to 117.6 kj/mol were found. For secondary salts the rotation mechanism is only operative in strongly acid solvents (pKa≤1.4). Other solvents show catalytic acceleration of the isomerization due to planar inversion on nitrogen (via a deprotonation p-protonation mechanism).
    Notes: Die Barrieren der Rotation in die CN-Doppelbindung bei Thioimidiumsäureester-Salzen 1-15 wurden mit Hilfe kinetischer und dynamischer NMR-Messungen ermittelt. In Abhängigkeit von sterischen und elektronischen Effekten wurden ΔG≠-Werte von 89.9 bis 117.6kj/mol erhalten. Der Rotationsmechanismus gilt bei sekundären Salzen nur bei Verwendung stark saurer Lösungs mittel (pKa≤1.4). In anderen Lösungsmitteln tritt über einen Deprotonierungs-Protonierungs mechanismus eine katalytische Beschleunigung der Isomerisierung durch planare Stickstoffinversion auf.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19761090315
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  • 9
    Electronic Resource
    Electronic Resource
    Alkylierungsreaktionen an Thioamiden, II. Untersuchungen zur E/Z-Isomerie und innermolekularen Beweglichkeit in Thioimidsäureestern (1976)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 109 (1976), S. 922-946 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Alkylation reactions of Thioamides, II: Investigations of E/Z Isomerism and Intramolecular Mobility in ThioimidatesA Series of N-substituted thioimidates A was prepared and investigated by n. m. r. spectroscopy. It is shown by direct thermal stereomutation and dynamic n. m. r. spectroscopy that an inversion mechanism and an imine-enamine tautomerism are pathways of the E/Z isomerization in A (ΔG≠=51.5 to 92.9 kj/mol).
    Notes: Es wurde eine Anzahl N-substituierter Thioimidsäureester A dargestellt und NMR-spektroskopisch untersucht. Durch direkte thermische Isomerisierung und dynamische NMR-Messungen konnte nachgewiesen werden, daß der Inversionsmechanismus und die imin-Enamin-Tautomerie Wege der E/Z-Isomerisierung bei A(ΔG≠= 51.5 bis 92.9 kj/mol) darstellen.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19761090314
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  • 10
    Electronic Resource
    Electronic Resource
    Selenoimidsäureester (1976)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 109 (1976), S. 956-964 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: SelenoimidatesThe new selenoimidates 3a-f were prepared and compared with imidates and thioimidates concerning their E/Z isomerism and barriers to isomerization.
    Notes: Die neuen Selenoimidsäureester 3a-f wurden dargestellt und hinsichtlich ihrer E/z-Isomerie und Isomerisierungsbarrieren mit Imidsäure- und Thioimidsäureestern verglichen.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19761090316
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