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V. D. Dyachenko S. G. Krivokolysko Yu. A. Sharanin V. P. Litvinov 《Chemistry of Heterocyclic Compounds》1997,33(7):793-798
Ammonium 6-amino-4-aryl-3,5-dicyano-1,4-dihydropyridine-2-thiolates were synthesized by recyclization of 4-aryl-2,6-diamino-3,5-dicyano-4H-thiopyranes in the presence of organic bases. On acidification of the products, the corresponding substituted 3,4-dihydropyridine-2(1H)-thiones were obtained which were used in the synthesis of 2-alkylthio-1,4-dihydropyridines, bis-(pyridyl-2)disulfides and thieno[2,3-b]pyridines.Deceased.T. G. Shevchenko Lugansk State Pedagogical Institute, Lugansk 348011. N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, Moscow 117913. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 909–914, July, 1997. 相似文献
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V. V. Plemenkov R. V. Ashirov O. A. Lodochnikova I. A. Litvinov R. N. Zagidullin 《Russian Journal of Organic Chemistry》2006,42(7):969-972
The Diels-Alder reaction of 1-methylcycloprop-2-ene-1-carbonitrile and coumalic acid methyl ester (methyl 2-oxo-2H-pyran-5-carboxylate) gave a 2:1 adduct with endo-syn configuration of both cyclopropane fragments, which was established by X-ray analysis. According to the 1H NMR data, the reaction involves intermediate formation of decarboxylated 1:1 adduct having a cycloheptatriene structure; its isomerization into the corresponding caradiene, followed by addition of the second dienophile molecule, was confirmed by quantum-chemical calculations. 相似文献
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B. Sun Yu. A. Litvinov P. M. Walker K. Beckert P. Beller F. Bosch D. Boutin C. Brandau L. Chen C. Dimopoulou H. Geissel R. Knöbel C. Kozhuharov J. Kurcewicz S. A. Litvinov M. Mazzocco J. Meng C. Nociforo F. Nolden W. R. Plass C. Scheidenberger M. Steck H. Weick M. Winkler 《The European Physical Journal A - Hadrons and Nuclei》2007,31(3):393-394
A new long-lived isomeric state in the near proton dripline nucleus 125Ce has been identified with Schottky mass spectrometry at GSI. The excitation energy E
* = 103(12)keV and the decay time of 193(1)s have been obtained from a single stored fully ionized 125m
Ce58+ ion. The data implies an E3 transition and a 1/2+ assignment for the spin of the isomer. 相似文献
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The four-point correlation function has been studied in Liouville field theory. If one of the fields is degenerate, such a
function is described in terms of Coulomb integrals. Some nontrivial relations for these integrals have been found that can
be used to obtain new exact results in conformal field theory. In particular, a four-point correlation function has been calculated
in minimal quantum gravity. The result agrees with the results obtained recently by different methods [A. A. Belavin and A.
B. Zamolodchikov, JETP Lett. 82, 7 (2005); Theor. Math. Phys. 147, 729 (2006); A. B. Zamolodchikov, Theor. Math. Phys. 142, 183 (2005); I. K. Kostov and V. B. Petkova, Theor. Math. Phys. 146, 108 (2006)].
The text was submitted by the authors in English. 相似文献
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The FRS-ESR facility at GSI provides one of the most efficient methods for direct mass measurements. In the present experiment,
exotic nuclei were produced via fragmentation of 152Sm projectiles in a thick beryllium target at 500-600 MeV/u, separated in-flight with the fragment separator FRS, and injected
into the storage-cooler ring ESR. Time-resolved Schottky Mass Spectrometry was applied for mass measurements of stored and
electron-cooled bare and few-electron ions. 373 different nuclides were identified by means of the spectra of their revolution
frequencies. Masses for 18 nuclides (84Zr, 92Ru, 94Rh, 107,108,110Sb, 111,112,114I, 118Ba, 122,123La, 124Ce, 127Pr, 129Nd, 132Pm, 134Sm, 137Eu) have been determined for the first time. Masses for 111,112I and 113Xe have been obtained via known α-decay energies. The experiment and first results will be presented. 相似文献
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G. L. Litvinov 《Journal of Mathematical Sciences》1987,38(2):1734-1761
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