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  • 1
    Electronic Resource
    Electronic Resource
    Stereocontrolled synthesis of 3-alkylindolines from (Z)-2-hydroxyindolenines (1996)
    Springer
    Monatshefte für Chemie 127 (1996), S. 691-699 
    Details
    ISSN: 1434-4475
    Keywords: 2-Hydroxyindolenines ; StereocontrolledGrignard alkylation ; 3-Alkylindolines ; Furo[2,3-b]indol-2-ones
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Eine einfache Methode zur Herstellung der 3-Alkylindoline2 und deren Umsetzung zu dencis-kondensierten tricyclischen γ-Lactonen3 aus den Allylalkoholen1 mittels einerGrignard-Verbindung wird beschrieben. Die Reaktion verläuft unter hoher Stereoselektivität bezüglich der zwei neu gebildeten Asymmetriezentren. Durch Oxidation mit Chromtrioxid erhält man aus den 3-Alkylindolinen2 die 2-Oxindolderivate4.
    Notes: Summary A convenient process for the synthesis of 3-alkylindolines2 and their transformation intocis-fused tricyclic γ-lactones3 from allylic alcohols1, mediated by aGrignard reagent, is described. This process proceeds with high stereocontrol at the two newly formed contiguous stereogenic centres. By oxidation with chromium oxide, 2-oxindole derivatives4 are obtained from 3-alkylindolines2.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00817260
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  • 2
    Electronic Resource
    Electronic Resource
    NMR studies of 4(3H)-quinazolinones and 4(3H)-quinazolinethiones (1995)
    Springer
    Monatshefte für Chemie 126 (1995), S. 789-794 
    Details
    ISSN: 1434-4475
    Keywords: 4(3H)-Quinazolinones ; 4(3H)-Quinazolinethiones ; 1H NMR ; 13C NMR
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Die1H- und13C-NMR-Spektren der 4(3H)-Chinazolinone1–6 und ihrer entsprechenden 4-Thione7–12 wurden zugeordnet. Dabei zeigte sich, daß eine frühere Zuordnung der beiden benzoiden Kohlenstoffe (C-5 und C-8) der Chinazolinone1,2,4 und5 falsch war. Ersatz des Sauerstoffs durch Schwefel in den nukleophilen Amiden1–6 führt insbesondere für C-4, aber auch für C-4a, C-5 und C-8a zu einer deutlichen Änderung der chemischen Verschiebung. Heteronukleare Kopplungskonstanten über eine und über mehrere Bindungen wurden bestimmt.
    Notes: Summary Unambiguous1H and13C NMR assignments for 4(3H)-quinazolinones1–6 and their corresponding 4-thiones7–12 have been made. This resulted in the revision of the previous assignments for the two benzenoid carbons (C-5 and C-8) of quinazolinones1,2,4, and5. Thionation of the nucleophilic amides1–6 has been found to cause a distinct change in the13C chemical shift of particularly C-4, but also of those of C-4a, C-5, and C-8a. One-bond and several long range heteronuclear coupling constants for the compounds have also been measured.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00807171
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  • 3
    Electronic Resource
    Electronic Resource
    Definitive assignment of the 13C NMR signals of the indole C-3 and C-3a carbons of the ajmaline, picraline and sarpagine alkaloids (1989)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 27 (1989), S. 155-157 
    Details
    ISSN: 0749-1581
    Keywords: 13C NMR ; Tetrahydrocarbazole ; Oxotetrahyrocarbazole ; Ajmaline alkaloids ; Picraline alkaloids ; Sarpagine alkaloids ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Comparison of a 1H coupled natural abundance 13C NMR spectrum of 1-oxo-1,2,3,4-tetrahydrocarbazole with a single-frequency experiment in which the hydrogens three bonds away from C-3 (indole numbering) were irradiated allowed the unambiguous distinction of the C-3 and C-3a signals. The results can be extrapolated for the assignment of the same signals in the ajmaline, picraline and sarpagine alkaloids, which also contain a carbonyl group as the substituent at the C-2 position of the indole skeleton. The effect of this carbonyl group on the chemical shifts of the benzenoid carbons is also discussed.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1260270212
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  • 4
    Electronic Resource
    Electronic Resource
    Utility of 1H/2H isotope shifts for the 13C NMR assignments of indole derivatives (1989)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 27 (1989), S. 75-80 
    Details
    ISSN: 0749-1581
    Keywords: Cycloalkano[b]indoles ; 13C NMR ; Isotope shifts ; Solvent effects ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The deuterium/hydrogen NMR isotope effects on the 13C chemical shift (DHIECS) of the cycloalkano[b]indoles 1,2,3,4-tetrahydro-9H-carbazole, 3-tert-butyl-1,2,3,4-tetrahydro-9H-carbazole and 1,2,3,4-tetrahydrocyclopent-[b]indole, wherein the labile NH was partially exchanged to ND, were measured at a concentration of 0.83 M in CDCI3 and in DMSO-d6 solutions. The DHIECS values show defined trends that allow definitive 13C NMR assignments. The isotope effects over three and four bonds for the sp3 hybridized carbons are linearly interdependent, even when one of these isotope effects becomes negative.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1260270114
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  • 5
    Electronic Resource
    Electronic Resource
    NMR studies of indoles and their N-carboalkoxy derivatives (1987)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 25 (1987), S. 911-918 
    Details
    ISSN: 0749-1581
    Keywords: Indoles ; N-carboalkoxyindoles ; substituent effects ; 13C NMR ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 13C NMR assignment of indoles and 5-methoxyindoles substituted at position 3, and some of their N-carboalkoxy derivatives, was achieved from one- and two-dimensional NMR experiments. Substituent chemical shifts and 1 J(CH) values were evaluated. The dynamic processes of N-carboalkoxyindoles and N-carboalkoxyindoline observed by high-field 1H NMR show the existence of two preferred rotamers around the carbamate N—C(=O)OR bond, which was interpreted in terms of frequency/field strength-dependent phenomena.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1260251016
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  • 6
    Electronic Resource
    Electronic Resource
    Isotope effects on the 13C NMR chemical shifts of 5-substituted indoles: Evidence for electron density dependence on the hydrogen (deuterium) atom (1989)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 27 (1989), S. 1039-1047 
    Details
    ISSN: 0749-1581
    Keywords: 13C NMR ; Deuterium isotope effects ; Electron density dependence ; 5-Substituted indoles ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The dependence of the deuterium/hydrogen NMR isotope effects on 13C chemical shift (DHIECS) values on the electron density at the hydrogen (deuterium) atom in a series of para-like substituted indoles with a partially deuterated NH site, measured as 0.83 M solutions in DMSO-d6, is established on the basis of a series of correlations relating the isotope shifts with Hammett-type í parameters, 1H(NH) chemical shifts, 15N chemical shifts and group electronegativity. The sensitivity of the nΔ isotope effects appears to be connected closely with electron redistribution at the 5-substituent of the carbon atom under consideration.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1260271106
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  • 7
    Electronic Resource
    Electronic Resource
    Unambiguous assignment of the 13C NMR spectra of methylindoles (1988)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 26 (1988), S. 552-558 
    Details
    ISSN: 0749-1581
    Keywords: Methylindoles ; 13C NMR ; Isotope shifts ; Solvent effects ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 13C NMR spectra of all possible indoles substituted with one, two or three methyl groups on the pyrrole ring were assigned from heteronuclear two-dimensional 13C/1H contour plots and homonuclear hydrogen-hydrogen decoupling experiments at a specific concentration of 0.83 M in CDCl3 and in DMSO-d6. The results confirm controversial assignments for some compounds, and provide the assignments for those compounds not previously studied by this technique. In addition, deuterium/hydrogen NMR isotope effect on 13C chemical shifts (DHIECS) for indoles, wherein the labile NH was partially exchanged to ND, are reported. In this way DHIECS values over two, three, four and five bonds were measured. The results in each solvent are discussed in terms of the number of bonds between the exchanged hydrogen and the observed carbon, and also according to their geometric dependence. This provides some evidence of the vibrational origin of the DHIECS.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1260260705
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  • 8
    Electronic Resource
    Electronic Resource
    13C NMR spectroscopy of indole derivatives (1987)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 25 (1987), S. 377-395 
    Details
    ISSN: 0749-1581
    Keywords: Indole ; 13C NMR ; indole alkaloids ; substituent effects ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The chemical shifts of 298 naturally occurring and synthetic compounds containing the indole chromophoric group are listed. Substituent effects on 13C chemical shifts (SCS) induced by substitution on the heteroaromatic five-membered ring are discussed. The data provide a reference set for future 13C NMR investigations and highlight the need for unambiguous experimental evidence to resolve controversial assignments for differently substituted representative indole derivatives. Many original assignments have been changed, and values not considered to be unambiguously assinged are delineated. The 1 J(CH) values for the parent indole were measured.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1260250502
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