ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 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
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    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
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    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
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Alkylierungsreaktionen an Thioamiden, IV. 1H-NMR-Untersuchungen zur innermolekularen Beweglichkeit bei Imidsäure- und Thioimidsäure-methylestern sowie ihren Salzen (1977)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 2463-2479 
    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, IV. 1H NMR Investigations of the Intramolecular Mobility in Methyl Imidates, Methyl Thioimidates, and their SaltsBy means of long distance fluorine coupling it is shown that the alkylation of secondary amides 1 and thioamides 2 leads to the imidium and thioimidium ester salts 3 and 4 which are obtained in the Z configuration. By deprotonation of 3(Z) with pyridine at low temperatures the benzimidates 5 can be liberated in the thermodynamic instable Z form. From the equilibration of 5(Z) (ΔGZ → E≠ 78.7 to 81.5 kJ/mol and ΔGZ → E≠ 89.2 to 90.2 kJ/mol) and dynamic NMR measurements in protic solvents the mechanism of planar nitrogen inversion was derived for the E/Z isomerization of benzimidates 5. In the same way kinetic and dynamic measurements were carried out with the corresponding thioimidates 6 (ΔGZ → E≠ 6 ≈ ΔGZ → E≠ 5) and the conjugate acids 3 and 4. The barriers to rotation about the CN double bond of the imidium ester salts 3 thus obtained were compared with that of 4 (ΔG≠ 3 〈 ΔG≠ 4).
    Notes: Durch Fluor-Fernkopplung wird nachgewiesen, daß bei der Alkylierung sekundärer Amide 1 und Thioamide 2 die Imidium- und Thioimidiumsäureester-Salze 3 und 4 in der Z-Konfiguration erhalten werden. Bei der Deprotonierung von 3(Z) mit Pyridin bei niedrigen Temperaturen können die Benzimidsäureester 5 in der thermodynamisch instabilen Z-Form freigesetzt werden. Aus der Gleichgewichtseinstellung von 5(Z) (ΔGZ → E≠ 78.7 bis 81.5 kJ/mol und ΔGZ → E≠ 89.2 bis 90.2 kJ/mol) und dynamischen NMR-Messungen in protischen Lösungsmitteln resultiert der Mechanismus der planaren Stickstoffinversion für die E/Z-Isomerisierung der Benzimidsäureester 5. In gleicher Weise werden kinetische und dynamische Messungen an den entsprechenden Thioimidsäureestern 6 (ΔGZ → E≠ 6 ≈ ΔGZ → E≠ 5) und den konjugaten Säuren 3 und 4 durchgeführt. Die so gewonnenen Barrieren der Rotation um die CN-Doppelbindung der Imidiumsäureester-Salze 3 werden mit denen von 4 verglichen (ΔG≠ 3 〈 ΔG≠ 4).
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19771100707
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    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
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    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
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    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
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    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
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    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
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    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
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...