Study of Amino-Imino Tautomerism in Derivatives of 2-, 4- and 6-Aminonicotinic Acid

Smrčková, Svatava; Juricová, Kristina; Prutianov, Viktor

doi:10.1135/cccc19942057

Cited by 10 publications

(5 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…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]. The effect of the NH 2 substituent has been studied in the case of 3,4-diaminopyridine, where partial charge redistribution is discussed [15].…”

Section: Introductionmentioning

confidence: 75%

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

Chapkanov

2009

Struct Chem

View full text Add to dashboard Cite

A distortion of the aromatic character as a result of the N py protonation of 2-aminopyridine was established by conventional and linear-polarized IR-spectroscopy, UV-and 1 H-NMR-spectral analysis of model system 2-aminopyridinium tetrachlorocuprate (II) salt. Quantum chemical ab initio calculations are performed at MP2 and B3LYP levels of theory and 6-311 ??G** basis set in order to determine the changes in the geometrical parameters and IR-spectroscopic characteristics as a result of N py protonation. The observed crystallochromy effect is discussed as well.

show abstract

Section: Introductionmentioning

confidence: 75%

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

Chapkanov

2009

Struct Chem

View full text Add to dashboard Cite

show abstract

“…In the course of preparation of 4-aminonicotinates from methyl 4-nitropyridine-3-carboxylate 1-oxide 1 we found a very simple substitution of the nitro group by the methoxy group under conditions of acid-catalyzed esterification 2 . This brought us to a more detailed study of nucleophilic aromatic substitution in the series of pyridine-1-oxide derivatives.…”

mentioning

confidence: 99%

Nucleophilic Substitution in a Series of 4-Nitronicotinic Acid 1-Oxide Derivatives

Pohl

Prutianov

Smrčková-Voltrová

1995

Collect. Czech. Chem. Commun.

Self Cite

View full text Add to dashboard Cite

Nucleophilic substitution of the nitro group in 4-nitro-3-pyridinecarboxanilide 1-oxide (IIa) afforded 4-hydroxy- (IIb), 4-chloro- (IIc), 4-methoxy- (IId), 4-ethoxy- (IIe), and 4-dimethylamino-3-pyridinecarboxanilide (IIf). The 1H and 13C NMR chemical shifts of the pyridine moiety were correlated with the Hammett constants of the substituent in position 4, with the exception of compound IIb. The reason of this phenomenon is discussed.

show abstract

“…The solvent was then evaporated under reduced pressure and the remaining oily product was co-distilled with toluene. The solid precipitate was washed with ether and dried.Yields and physical characteristics of the compounds IIa-IId, IIf and IIg are given in Table I, 1 H and 13 C NMR spectra in Tables IV and V, respectively. 1-(4-Cyanobenzyl)-3-carbamoyl-1,4-dihydropyridin-4-iminium Bromide (IIe) and 1-(4-Fluorobenzyl)-3-carbamoyl-1,4-dihydropyridin-4-iminium Bromide (IIh)…”

mentioning

confidence: 99%

“…The resulting white solid was filtered and dried. Yields and physical characteristics of the compounds IIe and IIh are given in Table I, 1 H and 13 C NMR spectra in Tables IV and V, …”

mentioning

confidence: 99%

See 1 more Smart Citation

Structure and Properties of Quaternized 2- and 4-Aminonicotinamides

Smrčková-Voltrová

Říha

Prutianov

1995

Collect. Czech. Chem. Commun.

Self Cite

View full text Add to dashboard Cite

Compounds 2-and 4-aminonicotinamide were quaternized with eight 4-substituted 1-bromomethylbenzenes to form 1-(4-substituted benzyl)-3-carbamoyl-1,2(1,4)-dihydropyridin-2(4)-iminium bromides. The optimal reaction conditions were found and the resulting iminium salts were characterized by 1 H and 13 C NMR spectra. No transmission of electronic effect of the substituent at the benzene ring on the spectral properties of dihydropyridine moiety was observed. The possible reason is discussed.In our previous communication 1 we have found 13 C NMR spectroscopy as a suitable tool for the proof of the structure of aminopyridine quaternary salts. We concluded that salts derived from 2-and 4-aminopyridine occur exclusively in the iminium form with dihydropyridine structure. This fact may be important from the biological point of view: dihydropyridiniminium structure behaves rather as an 1,4-dihydropyridine derivative than as a pyridinium quaternary salt and the hydride-donor properties are lost. This fact can be a reason of both the CNS activity of the alkaloid clitidin 2 and the powerful competitive inhibition of NAD by aminonicotinamide, which is by NADase catalyzed base-exchange reaction transformed into a coenzyme analog 3 . The chance to be therapeutically useful let us to the synthesis of 2-and 4-aminonicotinamides substituted in the position 1 with modified benzyl group. These compounds are interesting also from the chemical point of view, regarding the study on the substituent effects.The starting 2-aminonicotinamide was prepared from nicotinamide by oxidation to its N-oxide, chlorination with a mixture of phosphorus pentachloride and phosphorus oxychloride to 2-chloronicotinonitrile, reaction with alcoholic ammonia at 180 °C and hydrolysis according to the described procedure 4 . 4-Aminonicotinamide was obtained from the 3-methylpyridine-1-oxide by its nitration 5 , oxidation 6 to 4-nitronicotinic acid 1-oxide, catalytic hydrogenation 7 to 4-aminonicotinic acid and amide preparation via the anhydride intermediate 8 . The 1-substituted 2-and 4-aminonicotinamides I and II were prepared by reaction of the base with the corresponding 4-substituted 1-bromomethylbenzene in dimethylformamide or acetonitrile.Quaternized 2-and 4-Aminonicotinamides

show abstract

Study of Amino-Imino Tautomerism in Derivatives of 2-, 4- and 6-Aminonicotinic Acid

Cited by 10 publications

References 0 publications

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

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

Nucleophilic Substitution in a Series of 4-Nitronicotinic Acid 1-Oxide Derivatives

Structure and Properties of Quaternized 2- and 4-Aminonicotinamides

Contact Info

Product

Resources

About