A multinuclear NMR study of the restricted rotation in a bi-imidazole nucleosideâ Electronic supplementary information (ESI) available: the <sup>15</sup>N HMBC spectra together with the <sup>1</sup>H{<sup>13</sup>C} and <sup>1</sup>H{<sup>15</sup>N} HMBC correlations. See http://www.rsc.org/suppdata/p1/b0/b010182f/
Mäki, Jukka; Klika, Karel D.; Sjöholm, Rainer; Kronberg, Leif; Mäki Jukka; Department of Organic Chemistry, à bo Akademi University; Klika Karel D.; Department of Chemistry, University of Turku; Sjöholm Rainer; Department of Organic Chemistry, à bo Akademi University; Kronberg Leif; Department of Organic Chemistry, à bo Akademi University
Журнал:
Journal of the Chemical Society, Perkin Transactions 1
Дата:
2001
Аннотация:
Ethenoadenosine, a common nucleoside adduct known to be formed by the action of several industrial and environmental genotoxic compounds on adenosine, undergoes ring-opening in aqueous NaOH solution with the consequent loss of one carbon atom (C5). The prototropic equilibrium and protonation of the resultant bi-imidazole nucleoside was studied by <sup>1</sup>H, <sup>13</sup>C, and <sup>15</sup>N NMR spectroscopy and it was found that in the neutral form an intramolecular H-bonding is in effect between N3â ³ of the outer imidazole ring and the N6 protons of the inner imidazole ring, giving rise to degenerate tautomeric forms. In the protonated form it is the pyridine-type nitrogen (N3â ³) of the outer imidazole ring where the proton is predominately located and the reduced intramolecular H-bonding results in essentially unrestricted rotation of the imidazole rings with respect to one another.
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