Proton, carbon-13, and nitrogen-15 nuclear magnetic resonance and CNDO/2 studies on the tautomerism and conformation of amiloride, a novel acylguanidine was written by Smith, Robert L.;Cochran, David W.;Gund, Peter;Cragoe, Edward J. Jr.. And the article was included in Journal of the American Chemical Society in 1979.COA of Formula: C6H7ClN4O2 This article mentions the following:
The favored ground-state structures were determined for the novel acylguanidine diuretic, amiloride (I), and its free base using natural-abundance 1H, 13C, and 15N NMR techniques and CNDO/2 theor. calculations I existed primarily in the acylamino tautomer form as planar conformer F1, whereas the free base preferred the acylimino tautomer form as planar conformer A1 (and/or A4). The dynamic mechanism(s) for the exptl. observed rapid equilibrium of the terminal amino groups in I and the free base and, when N-substituted, their substituents were explored by the CNDO/2 method. Of the six possible pathways considered for effecting N-10-N-11 interconversion in the free base a novel mechanism involving a synchronous rotation around ϕ2 and ϕ3 was calculated to have the lowest barrier to interconversion. Exptl. verification of this novel mechanism was attempted, but not found, by preparation of an appropriate model, II and subsequent determination of the ΔG values (14.7-14.8 kcal/mol) for II and pyrazine analogs using the dynamic 13C NMR technique in Me2SO-d6-CD3OI). The free base is likely to undergo N-10-N-11 interconversion via simple ϕ3 rotation and/or ϕ2 rotation plus inversion. Accordingly, I must equilibrate by a ϕ3 rotation mechanism. In the experiment, the researchers used many compounds, for example, Methyl 3,5-diamino-6-chloropyrazine-2-carboxylate (cas: 1458-01-1COA of Formula: C6H7ClN4O2).
Methyl 3,5-diamino-6-chloropyrazine-2-carboxylate (cas: 1458-01-1) belongs to pyrazine derivatives. Pyrazine derivatives have antitumor, antibiotic, anticonvulsant, antituberculous and diuretic effects as well as kinase, enzymatic and potent tubulin and FtsZ polymerization inhibitory activities. Pyrazine and a variety of alkylpyrazines are flavor and aroma compounds found in baked and roasted goods. Tetramethylpyrazine (also known as ligustrazine) is reported to scavenge superoxide anion and decrease nitric oxide production in human Granulocytes.COA of Formula: C6H7ClN4O2