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L. D. Smirnov S. V. Nikitin A. I. Chernyshev A. A. Sorokin V. P. Lezina V. G. Zabrodnyaya M. M. Kaganskii 《Chemistry of Heterocyclic Compounds》1992,28(12):1425-1431
It has been shown that the alkylation of 2-methyl-9-hydroxy-4H-pyrido[1,2-a]pyrimidin-4-one takes place at the oxygen atom, but electrophilic substitution takes place mainly at position 8 of the molecule (the ortho position relative to the hydroxy group).Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1660–1666, December, 1992. 相似文献
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M. M. Kaganskii G. G. Dvoryantseva I. V. Sokolova V. I. Danilova 《Chemistry of Heterocyclic Compounds》1975,11(1):102-107
The nature of theπ→π * transitions in the spectra of quinoxaline 1-N-oxides as compared with unoxidized quinoxalines was examined on the basis of an experimental, study and calculation by the Pariser-Parr-Pople configurational interaction method. 相似文献
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M. M. Kaganskii G. G. Dvoryantseva A. S. Elina 《Chemistry of Heterocyclic Compounds》1973,9(3):369-373
The UV spectra of the bases and cations of a number of 2-substituted quinoxaline derivatives were investigated, and their basicity constants were determined. The investigated compounds were divided into two series, characterized, respectively, by ortho and meta orientations of the substituent and cationoid center, on the basis of correlations of the pKa values with the Hammett—Taft constants. The effect of the position of the protonation center relative to the substituent on the energy of the * transitions was examined within the framework of the simple MO LCAO method. The results of the calculations are compared with the experimentally observed shift in the1Lb band in the UV spectra of some 2-substituted quinoxalines on passing from the bases to the monocations.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 398–403, March, 1973. 相似文献
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Struchkova M. I. Gusarov A. N. Dvoryantseva G. G. Evstigneeva R. P. Ioslovich N. V. Kabankin A. S. Kaganskii M. M. Landau M. A. 《Chemistry of Heterocyclic Compounds》1977,13(9):985-991
The nature of the * transitions in the spectra of neutral molecules of - and -formyl-, acetyl-, and -carbomethoxypyrroles above 210 nm was examined on the basis of an experimental study and calculation by the Pariser-Parr-Pople (PPP) configuration interaction (CI) method. The effect of protonation on the position and intensity of the monotypic transitions was studied. The electronic structures and the energies of the neutral and all of the theoretically possible protonated forms of and -formylpyrroles were calculated within the framework of the CNDO/2 (complete neglect of differential overlap) method. The results of the calculations are in agreement with the experimental data and are in conformity with the greatest energetic advantageousness of protonation of these compounds at the oxygen atom of the carbonyl group.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1221–1228, September, 1977. 相似文献
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G. G. Dvoryantseva M. M. Kaganskii I. S. Musatova A. S. Elina 《Chemistry of Heterocyclic Compounds》1974,10(11):1366-1370
The electronic spectra of neutral molecules and monocations of N-oxides of 2- and 3-substituted pyrazines and quinoxalines were measured, and their ionization constants in water were determined. The position of the protonation center in the investigated compounds was established. 相似文献
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