An ab initio study of protonation and alkylation of aminopyridine

Pyridinium N-(2′-Azinyl)Aminides: Regioselective Synthesis of 2-Alkylaminoazines

“…3 Generally, regioselectivity of the substitution reaction can be predicted by considering both HSAB theory and steric hindrance. 2,4,5 When reacted with primary halides other than benzyl chloride, 6 heterocyclic aminides yield only the endosubstituted isomer.…”

On the tautomerism and color origin in solid state of Npy-protonated-2-aminopyridine: spectroscopic elucidation

“…However, in the pyridinium salts a different situation can be expected with respect to structure obtained. The theoretical results including STO-3G* ab initio calculations also predict the endocyclic nitrogen atom as a favorable position of protonation [8], but a final stabilization of the ''imino'' form have been established using IR-spectral studies of the hydrochloride and tetrchloropalladate (II) [9][10][11]. Similar conclusions have been obtained by means of a comparative 1 H-NMR-spectral analysis of 4-aminopyridine (AP) and its salts or in the case of 4-dimetylaminopyridinium hydrogensquarate [10][11][12][13][14].…”

“…channel inhibitor have been discussed [1][2][3] as well as the assumption about the biological effect of their transition metal complexes. Their coordination capability has been also studied [4][5][6] providing evidences, that different substituted aminopyridines coordinated mainly as a monodentate manner, in result of a very strong nucleophilic ability of the pyridine (endocyclic) nitrogen atom [7,8]. As such the coordination way should not be expected to change the aromatic structure of the ligand and this conclusion has been confirmed by comparison of the pyridine skeleton characteristic bands in the IR-spectra of 3-and 4-aminopyridine and their complexes with transition metals [4][5][6].…”

Conformational evaluation and detailed 1H and 13C NMR assignments of flavoxate, a urinary tract antispasmodic agent

“…Spectra were referenced to TMS for 1 H and 13 C. The two-dimensional correlation experiments were performed using standard manufacturer-supplied HETCOR, gHMBC [9], NOESY and INADEQUATE [10] pulse sequences. The spectral widths in the gHMBC experiment were 18115.9 Hz for F 1 and 3597.1 Hz for F 2 and the experiment was optimized for a 1 J(C, H) value of 140 Hz.…”