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  • 1
    Electronic Resource
    Electronic Resource
    Asymmetrische reduktive Aminierung von Cycloalkanonen 2. Synthese und absolute Konfiguration 2-substituierter Cyclohexanamine (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 2076-2098 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Asymmetric Reductive Amination of Cycloalkanones, 2. Synthesis and Absolute Configuration of 2-Substituted CyclohexanaminesAsymmetric synthesis of 2-substituted cyclohexanamines from racemic cyclohexanones by means of reductive amination in a three-step procedure is described. Condensation of the ketones 5 with the optically active auxiliary amines 6 leads to the imines 7, which are hydrogenated to the secondary amines 8 with Raney nickel. Hydrogenolysis with palladium-on-charcoal yields the primary amines 9. With Raney nickel as catalyst the synthesis of the amines 8 and 9 runs with high chemical yield under complete diastereomeric and high grade enantiomeric control, respectively. Enantiomeric excess is determined via the diastereomeric acylamines 10 by means of HPLC. Stereochemical analysis including the absolute configuration of 8 and 9 is performed with 1H, 13C NMR spectroscopy, via the CD of the salicylidenes 11 and the X-ray spectrum of the amine 9c. - Reaction mechanism is investigated via the partially deuterated amine 13 to come up as a kinetically controlled asymmetric hydrogenation combined with a thermodynamically controlled transformation.
    Notes: Die asymmetrische Synthese von 2-substituierten Cyclohexanaminen aus racemischen Cyclohexanonen durch reduktive Aminierung in einem Dreistufenverfahren wird beschrieben. Die aus den Ketonen 5 durch Umsetzung mit den optisch aktiven Hilfsaminen 6 leicht zugänglichen Imine 7 werden mit Raney-Nickel zu den sekundären Aminen 8 hydriert. Hydrogenolyse über Palladium-Katalysator führt zu den primären Aminen 9. Mit Raney-Nickel gelingt in sehr guten chemischen Ausbeuten die Synthese der diastereomer reinen und hochgradig enantiomer reinen Amine 8 bzw. 9. Die Enantiomerenreinheit der Amine 9 wird über die diastereomeren Acylamine 10 durch HPLC bestimmt. Die Stereochemie einschließlich der absoluten Konfiguration der Verbindungen 8 und 9 wird durch 1H-, 13C-NMR, durch CD der Salicylidene 11 und das Röntgenbeugungsspektrum von Amin 9c ermittelt. - Als Reaktionsmechanismus wird eine kinetisch gesteuerte asymmetrische Hydrierung mit vorgelagerter thermodynamischer Transformation über die partiell deuterierte Verbindung 13 nachgewiesen.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19841170607
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  • 2
    Electronic Resource
    Electronic Resource
    Reversed substituent effect for the 13C NMR chemical shifts in the unsubstituted ring of para-substituted benzophenones (1980)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 14 (1980), S. 444-446 
    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 chemical shifts of the C-1′ carbon atom of fifteen para-substituted benzophenones correlate with the F and R substituent constants in a reversed manner.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1270140604
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  • 3
    Electronic Resource
    Electronic Resource
    Asymmetrische reduktive Aminierung von Cycloalkanonen, 5. Synthese und absolute Konfiguration 2-substituierter Cyclopentanamine (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 2668-2677 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Asymmetric Reductive Amination of Cycloalkanones, 5. Synthesis and Absolute Configuration of 2-Substituted CyclopentanaminesIn an asymmetric synthesis 2-substituted cyclopentanamines are obtained from racemic cyclopentanones by means of reductive amination in a three-step procedure. Condensation of the ketones 3(n) with optically active 1-phenylethylamines yields imine mixtures 4(n), which are hydrogenated with Raney nickel to give the optically active, diastereomerically pure secondary amines 5(n). Hydrogenolysis with Palladium-on-charcoal leads to high grade enantiomerically pure primary amines 6(n) with good yields. The relative configuration of the amines 5(n) and 6(n) is elucidated by 1H and 13C NMR techniques. The absolute configuration is determined by X-ray analysis of the 4-bromobenzamide 8 of the primary amine (+)-6(n)e and with the help of CD of the salicylidenes 9(n). The kinetically controlled asymmetric hydrogenation with a first order transformation as proved reaction mechanism in the cyclohexanamine line is confirmed for this investigation. The hydrogenation runs like-induced to the cis-configurated amines 5(n) and 6(n), respectively.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19861190823
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  • 4
    Electronic Resource
    Electronic Resource
    13C nuclear magnetic resonance spectra of amaryllidaceae alkaloids. I - alkaloids with the crinane skeleton (1985)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 23 (1985), S. 804-808 
    Details
    ISSN: 0749-1581
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The13C NMR spectra of 15 Amaryllidaceae alkaloids with the crinane skeleton were measured and the chemical shifts unequivocally assigned. From the derived specific shift ranges, it is possible to establish both the complete oxygenation pattern of the 5, 10b-ethanophenanthridine skeleton and its stereochemical arrangement.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1260231004
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  • 5
    Electronic Resource
    Electronic Resource
    Differentiation of diastereomeric 2-substituted cyclohexanamines with three chirality centres by 13C NMR spectroscopy (1988)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 26 (1988), S. 37-41 
    Details
    ISSN: 0749-1581
    Keywords: 13C NMR ; optically active cyclohexanamines ; diestereomeric 2-methyl-N-(1-phenylethyl) cyclohexamines ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 13C NMR spectra of optically active primary and secondary 2-substituted cyclohexanamines were measured and the chemical shifts were unequivocally assigned. Similar studies were made with four diastereomeric 2-methyl-N-(1-phenylethyl)cyclohexanamines with three chirality centres.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1260260110
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  • 6
    Electronic Resource
    Electronic Resource
    Structure establishment by two-dimensional NMR spectroscopy of the product obtained in the reaction of MCPBA and himachalol and revised 1H NMR assignments for himachalolNMR Spectral Investigation, Part 31; for Part 30, see Ref. 1. CIMAP publication no. 861. (1992)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 30 (1992), S. 1079-1083 
    Details
    ISSN: 0749-1581
    Keywords: Structure elucidation ; 2D NMR rearrangement product ; 3α,4α-Epoxyhimachalane-2α,7α-diol ; Himachalol revised 1H NMR assignments ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of himachalol with m-chloroperoxybenzoic acid afforded a rearrangement product, the structure of which was deduced by 2D NMR analysis to be 3α,4α-epoxyhimachalane-2α,7α-diol. The recently proposed 1H NMR assignments for himachalol have been revised, based on the analysis of 2D COSY, DEPT, HETCOR and NOE experiments.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1260301110
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  • 7
    Electronic Resource
    Electronic Resource
    An investigation of the keto-enol tautomerism in 2-acetyl-1-tetralone by 2D NMR spectroscopy13C NMR spectral investigation, Part 23. For Part 22, see Ref. 1, CIMAP Publication No. 21/90. (1990)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 28 (1990), S. 931-933 
    Details
    ISSN: 0749-1581
    Keywords: 2D NMR ; Spectroscopy ; 2-acetyl-1-tetralone endo-enolic form ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Long-range CH correlation and long-range selective proton decoupling (LRSPD), together with other standard NMR techniques, led to the complete 13C and 1H NMR spectral assignments of 2-acetyl-1-tetralone and demonstrated its existence in the endo-enolic form.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1260281105
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