17o and 14n nmr studies of quinoxaline-2(1h),3(4h)-diones and n,n'-substituted oxamides: The first experimental evidence of torsion angle deformation resulting from an unprecedented through six-bond substituent effect on the diamide group of quinoxaline-2(1h),3(4h)-diones

Tetrahedron Letters

Volumn 37, Issue 18, 1996, Pages 3191-3194

  Gerothanassis, Ioannis P ^a   Cobb, Jonathan ^b   Kimbaris, Athanasios ^a   Smith, John A S ^b   Varvounis, George ^a  

^a UNIVERSITY OF IOANNINA   (Greece)

^b KING'S COLLEGE LONDON   (United Kingdom)

Author keywords

[No Author keywords available]

Indexed keywords

2,3 QUINOXALINEDIONE DERIVATIVE;

ARTICLE; DRUG STRUCTURE; NUCLEAR MAGNETIC RESONANCE;

EID: 0029903032     PISSN: 00404039     EISSN: None     Source Type: Journal    
DOI: 10.1016/0040-4039(96)00492-3     Document Type: Article

References (20)

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12. 3CN and acetone, help to obtain narrow linewidths (see: Gerothanassis, I.P. Org. Magn. Reson. 1983, 21, 719-722). Unfortunately, the low solubility of quinoxaline-2(1H),3(4H)-diones in these solvents significantly reduces the required signal to noise ratio.
13. Levy, G. C.; Lichter, R. L. Nitrogen-15 Nuclear Magnetic Resonance Spectroscopy, Wiley-Interscience: New York, 1979.
14. Svensson, C. Acta Chem. Scand. B 1976, 30, 581-584.
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16. (a) Boykin, D. W.; Baumstark, A.L. Tetrahedron 1989, 45, 3613-3651;
17. 17O NMR Spectroscopy in Organic Chemistry, CRC Press Inc.: Boston, 1991;
18. (c) Baumstark, A. L.; Balakrishnan, P.; Dotrong, M.; McCloskey, C. J.; Oakley, M. G.; Boykin, D. W. J. Am. Chem. Soc. 1987, 109, 1059-1062.
19. Cobb, J.; Haq, M. M. I.; Kurshid, M. M. P.; Smith, J. A. S. Chem. Phys. 1993, 169, 65-74.
20. Interestingly, extensive out-of-plane deformation of the quinoxaline ring has been observed in the X-ray structure of the sterically hindered 2,3-di-tert-butylquinoxaline (see: Visser, G.J.; Vos, A. Acta Cryst. 1971, B27, 1793-1801).