ISSN:
0749-1581
Keywords:
13C NMR
;
13C Relaxation Times
;
Prototropic equilibria
;
Chemistry
;
Analytical Chemistry and Spectroscopy
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Quaternary 13C dipole-dipole spin-lattice relaxation times are used to analyse prototropic equilibria of 2-acetylbenzimidazole (1) and 4-azabenzimidazole in DMSO-d6 solutions. For the first compound, fast exchange between the two chelated structures prevails for 13C relaxation times, whereas proton and 13C chemical shifts characterize a slow exchange. For 4-azabenzimidazole, 13C and 1H spectra do not exhibit absorptions from structures in slow exchange. Analysis of the T1 values of carbons 8 and 9 before and after isotopic exchange of the labile amino hydrogen clearly show that the major component of the equilibrium is the 3H structure.
Additional Material:
5 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/mrc.1260250105
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