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171.
G. L. Rusinov R. I. Ishmetova N. I. Latosh I. N. Ganebnych O. N. Chupakhin V. A. Potemkin 《Russian Chemical Bulletin》2000,49(2):355-362
A number of 1,4-dihydropyridazines and pyridazines were prepared by the Diels-Alder reaction with an inverse electron demand
from cyclic heterodiene systems, 3,6-bis(3,5-dimethyl-4-R-pyrazol-1-yl)-1,2,4,5-tetrazines, and some enamines as well as from
4-vinylpyridine, butyl vinyl ether, phenylacetylene, and acrylamide. The reaction of 3,6-bis(3,5-dimethylpyrazol-1-yl)-1,2,4,5-tetrazine
with styrene afforded 4,5-dihydropyridazine, which was readily oxidized by atmospheric oxygen to form the corresponding pyridazine.
Electron-withdrawing substituents (Br or Cl) in the pyrazole rings accelerate [4+2]-cycloaddition. When heated, 1,4-dihydropyridazines,
which were synthesized from tetrazines and enamines, eliminated amine to give pyridazines. The reactivities of tetrazines
were evaluated by quantum-chemical methods.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 354–360, February, 2000. 相似文献
172.
R. E. Trifonov V. A. Ostrovskii V. L. Rusinov O. N. Chupakhin 《Russian Journal of Organic Chemistry》2013,49(3):450-454
The basicity of some 1,2,4-triazine 4-oxides was estimated on a quantitative level, and their probable protonation patterns were ascertained. The dissociation constants of mono- and diprotonated 3-R-6-phenyl-1,2,4-triazine 4-oxides in aqueous buffer solutions and aqueous sulfuric acid solutions were determined (6-phenyl-1,2,4-triazine 4-oxide: $pK_{BH^ + } = 1.1$ , $pK_{BH^{2 + } } = - 6.02$ ). According to the results of DFT calculations (B3LYP/6-311**) and spectral data, first protonation of 1,2,4-triazine 4-oxides involves the N1 nitrogen atom, and the second proton adds to the N-oxide oxygen atom. 相似文献
173.
174.
175.
L. A. Petrov A. B. Shishmakov S. V. Vakarin O. L. Semerikova A. A. Melyaeva Yu. V. Mikushina Yu. P. Zaikov O. N. Chupakhin 《Russian Journal of Inorganic Chemistry》2014,59(1):7-10
Tungsten oxide bronzes were produced by an original method of high-temperature electrochemical deposition. Their catalytic properties in a model process of desulfurization of petroleum products-benzothiophene peroxidation were studied. The effect of the particle size on the catalytic and catalase activity of samples was shown. 相似文献
176.
177.
D. N. Kozhevnikov A. M. Prokhorov V. L. Rusinov O. N. Chupakhin 《Chemistry of Heterocyclic Compounds》2004,40(7):911-915
The addition of CH-active compounds to 6-aryl-1,2,4-triazine 4-oxide is reversible and occurs under conditions of kinetic control at position 5 of the heterocycle to form cyclic C(5)-H adducts. Under conditions of thermodynamic control the nucleophilic attack is directed to position 3 of the heterocycle and is accompanied by its opening to form the more stable open chain addition products. Attack of ethylmagnesium bromide is directed exclusively to the 5 position of the 6-aryl-1,2,4-triazine 4-oxides as a result of the irreversibility of the given reaction. 相似文献
178.
V. N. Charushin V. G. Baklykov O. N. Chupakhin V. N. Drozd 《Chemistry of Heterocyclic Compounds》1985,21(3):331-338
4-Alkyl-2-phenyl-3a,4,9,9a-tetrahydrothiazolo[4,5-b]quinoxalines undergo isomerization in chloroform in the presence of acids to the regioisomeric (with respect to them) 9-alkyl-substituted derivatives. Under the same conditions 2,4-dimethyl-3a,4-9,9a-tetrahydrothiazolo [4,5-b]quinoxaline undergoes isomerization to 4-methyl-1H-2,3,3a,4,9,9a-hexahydropyrrolo[2,3-b]quinoxaline-2-thione. It was demonstrated by means of deuterium labels that in both cases the isomerization proceeds through a step involving dissociation to a quinoxalinium cation and the corresponding thioamide.See [1] for Communication 14.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 396–403, March, 1985. 相似文献
179.
N. A. Klyuev V. G. Baklykov V. N. Charushin O. N. Chupakhin 《Chemistry of Heterocyclic Compounds》1989,25(4):444-450
Based on a study of electron impact mass spectra of a large number of tetrahydropyrazines, which are joined to five- and six-membered heterocyclic and carbocyclic residues, the trends which characterize the stability of these condensed systems are found. The proposed criteria can be used for evaluation of the chemical stability of these compounds, for example, their propensity toward the reverse dissociation reaction.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 532–538, April, 1989. 相似文献
180.
V. L. Rusinov T. L. Pilicheva O. N. Chupakhin N. A. Klyuev D. T. Allakhverdieva 《Chemistry of Heterocyclic Compounds》1986,22(5):543-546
Condensation of diazoles with -dicarbonyl nitro compounds (nitromalondialdehyde and nitromalondiester) gives derivatives of azolo[5,1-c] [1,2,4]triazine with a nitro group in the triazine ring.For 4, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 662–665, May, 1986. 相似文献