Indigodiimine: A highly fluxional molecule that tautomerizes via double proton transfers

Journal of the American Chemical Society

Volumn 118, Issue 49, 1996, Pages 12459-12460

  Thoburn, John D ^a   Lüttke, Wolfgang ^c   Benedict, Claudia ^b   Limbach, Hans Heinrich ^b  

^a SANTA CLARA UNIVERSITY   (United States)

^b FREIE UNIVERSITÄT BERLIN   (Germany)

^c UNIVERSITY OF GÖTTINGEN   (Germany)

Author keywords

[No Author keywords available]

Indexed keywords

INDIGO DERIVATIVE; INDOLE DERIVATIVE; UNCLASSIFIED DRUG;

ARTICLE; DRUG STRUCTURE; MOLECULAR DYNAMICS; NUCLEAR MAGNETIC RESONANCE;

EID: 0030475397     PISSN: 00027863     EISSN: None     Source Type: Journal    
DOI: 10.1021/ja962515p     Document Type: Article

References (24)

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2. For a more recent example see: Chudoba, C.; Lutgen, S.; Jentzch, T.; Riedle, E; Woemer, M.; Elsässer, W. Chem. Phys. Lett. 1995, 240, 35.
3. For a review of the properties of indigo and its derivatives see:
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5. (b) Susse, P.; Steins, M.; Kupcik, V. Z Kristallographie 1988, 184, 269 (crystallography),
6. Tatsch, E.; Schrader, B. J. Roman Spectrosc. 1995, 26, 476 (vibrational spectroscopy).
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14. Lüttke, W.; Sieghold, H. Angew. Chem. 1975, 87, 63;
15. Angeu: Chem., Int. Ed. Engl. 1975, 14, 52.
16. Indigodiimine was prepared from indole according to the literature methods: Madelung, W. Liebigs Ann. Chem. 1914, 58, 405. Sieghold, H. Dissertation, Universität Göttingen, 1973.
17. 2, is liquid down to 130 K. It was prepared according to: Siegel, J. S.; Anet, F. A. L. J. Org. Chem. 1988, 53, 2629.
18. -1.
19. oW = 12 Hz. The chemical shifts, v, were taken to be temperature independent. For details see ref 17a.
20. -1.
21. (a) Limbach, H. H. Dynamic NMR Spectroscopy in the Presence of Kinetic Isotope Effects, In NMR Basic Principles and Progress; Springer: Berlin, 1991; Vol. 26 Chapter 2.
22. (b) Braun, J.; Schlabach, M.; Wehrte, B.; Köcher, M; Vogel, E.; Limbach, H. H. J. Am. Chem. Soc. 1994, 116, 6593.
23. Prevorsek, D. C. J. Phys. Chem. 1962, 66, 769.
24. Häfelinger, G.; Kuske, F. K. H. In The Chemistry of Amidines and Imidates; Patai, S., Rappoport, Z., Eds.; J. Wiley & Sons: New York, 1991; Vol. 2, pp 66-70. The tautomeric preferences reverse in N-alkyl amidines where the imino form is preferred over the amino form.