C 98 Cyclization of N-alkylazinium cations with bisnucleophiles. 6. Cycloelimination of tetrahydro-endo-furo[2,3-b]quinoxalines leading to 2,3-disubstituted tetrahydroquinoxalines [Electronic resource] / M. G. Ponizovskii, O. N. Chupakhin, V. N. Charushin, G. G. Aleksandrov> // Chemistry of Heterocyclic Compounds. - 1982. - Vol. 18, № 10. - P1098-1103. - Bibliogr. : p. 1103 (10 ref.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): N-METHYLQUINOXALINIUM SALT -- β-DIKETONE -- TETRAHYDROQUINOXALINE Аннотация: The reaction of an N-methylquinoxalinium salt with a β-diketone under thermodynamic-control conditions leads to 2,3-disubstituted tetrahydroquinoxaline via cycloelimination of the initially formed tetrahydro-endo-furo[2,3-b]quinoxaline \\\\expert2\\nbo\\Chemistry of Heterocyclic Compounds\\1982, v.18, N 10, p.1098.pdf |
C 98 Cyclization of N-alkylazinium cations with bifunctional nucleophiles. 25. Oxidation of tetrahydroquinoxalines condensed with six-membered ring heterocycles [Electronic resource] / V. N. Charushin, L. M. Naumova, M. G. Ponizovskii, V. G. Baklykov, O. N. Chupakhin> // Chemistry of Heterocyclic Compounds. - 1987. - Vol. 23, № 9. - С. 1010-1013. - Bibliogr. : p. 1013 (11 ref.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): TETRAHYDROQUINOXALINES -- POTASSIUM PERMANGANATE -- OXIDATION PRODUCTS Аннотация: Reaction of six-membered ring heterocycle-annulated tetrahydroquinoxalines with potassium permanganate in acetone results in the formation of oxidation products containing a common system of conjugated double bonds. \\\\expert2\\nbo\\Chemistry of Heterocyclic Compounds\\1987, v.23, N 9, p. 1010.pdf |
C 98 Cyclizations of N-alkyl-substituted azinium cations with bifunctional nucleophiles. 28. Orientation of the nucleophile in the reaction of quinoxalinium salts with indan-1,3-dione [Electronic resource] / G. M. Petrova, M. G. Ponizovskii, V. N. Charushin, G. G. Aleksandrov, E. O. Sidorov, O. N. Chupakhin> // Chemistry of Heterocyclic Compounds. - 1990. - Vol. 26, № 5. - С. 565-572. - Bibliogr. : p. 572 (12 ref.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): QUINOXALINUM SALTS -- C-NUCLEOPHILES -- AZINIUM CATIONS Аннотация: In reactions with quinoxalinium salts in alcoholic-base media indan-1,3-dione acts as a C nucleophile, adding at the 2 or 3 position of the heterocycle to give the corresponding ylidene derivatives; attack by the nucleophile at the C(3) atom (the Β position relative to the quaternary nitrogen atom) is preceded by addition of alcohol at the a position. Dissociative substitution at the C(2) atom in 2-alkoxy-3-(1,3-dioxoindan-2-ylidene)-1,2,3,4-tetrahydroquinoxalines by another nucleophile makes it possible to regard lyate complexes as probable intermediates in cyclizations of 1,4-diazinium salts with dinucleophiles. \\\\expert2\\nbo\\Chemistry of Heterocyclic Compounds\\1990, v.26, N 5, p.565.pdf |
1H and 13C NMR spectra of tetrahydroquinoxalines condensed with six-membered heterocycles [Electronic resource] / V. N. Charushin, N. N. Sorokin, A. I. Chernyshev, V. G. Baklykov, M. G. Ponizovskii, O. N. Chupakhin> // Magnetic Resonance in Chemistry. - 1986. - Vol. 24, № 9. - С. 777-782. - Bibliogr. : p. 782 (16 ref.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): 1H NMR -- 13C NMR -- CONDENSED TETRAHYDROQUINOXALINES Аннотация: The 1H and 13C NMR spectra of tetrahydroquinoxalines condensed with pyridazine, pyrazine, oxazine, oxadiazine, thiadiazine or triazine rings have been measured in DMSO-d6 solution. The effects of six-membered heterocycles on 1H and 13C chemical shifts and the values of one-bond 1J(CH) and vicinal 3J(HH) coupling constants for the ring junction fragment are considered. The differences between the 1H and 13C spectral parameters of tetrahydroquinoxalines annelated with five- or six-membered heterocycles with the same set of heteroatoms attached to the ring junction carbons are also discussed. \\\\expert2\\nbo\\Magnetic Resonance in Chemistry\\1986, v.24, N 9, p.777.pdf |
A 67 Application of 1H and 13C NMR to the structural elucidation of tetrahydroquinoxalines condensed with five-membered heterocycles [Electronic resource] / V. N. Charushin, A. I. Chernyshev, N. N. Sorokin, O. N. Chupakhin> // Organic Magnetic Resonance. - 1984. - Vol. 22, № 12. - P775-778. - Bibliogr. : p. 778 (22 ref.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): N-METHYLTETRAHYDROQUINOXALINES -- PYRROLE -- IMIDAZOLE Аннотация: 1H and 13C NMR spectral data for 21 N-methyltetrahydroquinoxalines annelated with furan, pyrrole, imidazole or thiazole rings are reported. Unambiguous assignments of the ring junction 13C resonances were made on the basis of selective decoupling experiments and with the aid of one-bond and long-range 13C–1H coupling constants. The effects of five-membered heterocycles on the 1H and 13C chemical shifts of the ring junction hydrogen and carbon atoms are considered. Values of one-bond 1J(CH) and vicinal 3J(HH) coupling constants between the ring junction protons are also discussed as a diagnostic means for structural elucidation of tetrahydroquinoxalines condensed with five-membered heterocycles. \\\\expert2\\nbo\\Organic Magnetic Resonance\\1984. V. 22, N 12. P. 775.pdf |