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31.
Bubel' O. N. Tishchenko I. G. Ptashnikov Yu. L. 《Chemistry of Heterocyclic Compounds》1982,18(8):773-775
2-Acetyloxiranes react with acetonitrile in the presence of equimolar amounts of Lewis acids. It was established that the use of boron trifluoride etherate or sulfuric acid as the catalyst leads to 2,7- and 3,6-diepoxy-1,5-dioxocanes, the use of aluminum trichloride, as well as stannic chloride, leads to the corresponding chlorohydrins, while the use of gaseous boron trifluoride leads to 2-oxazolines in satisfactory yields. It is shown that the reaction is regio- and stereospecific and that the resulting substituted 2-methyl-5-acetyl-2-oxazolines have a cis configuration.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No, 8, pp. 1022–1024, August, 1982. 相似文献
32.
O. N. Bubel' I. G. Tishchenko G. Z. Stasevich E. L. Veraksich E. R. Filich 《Chemistry of Heterocyclic Compounds》1985,21(10):1082-1085
A method for the synthesis of acetylthiiranes was developed; this method includes the conversion of acetyloxiranes to diethylketals, dealkoxylation of the latter, replacement of the oxygen atom of the oxirane ring by sulfur, and acidic hydrolysis of the ethoxyvinylthiiranes to acetylthiiranes.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1322–1326, October, 1985. 相似文献
33.
A new, general and exact method for resolving waveguide and grating problems is presented whereby the unknown electric field in a given dielectric distribution in the presence of an arbitrary source distribution can be obtained exactly from the known complete electric field solution in a simpler dielectric structure in the presence of the same source distribution. The method can be used in the form of an iterative scheme. The solution can also be obtained through an implicit equation which can be solved numerically without convergence problem by matrix inversion. The application of the method to the case of abnormal reflection under normal incidence from a segmented waveguide is given as an example. 相似文献
34.
V. V. Bobkov R. I. Starovoitov L. P. Tishchenko Yu. I. Kovtunenko L. A. Gamayunova 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2014,8(5):853-858
The results of studying the accumulation and thermal desorption of ion-implanted deuterium from tungsten films deposited on various composite substrates are presented. The influence of the tungsten-film thickness and irradiation dose with D+ ions of intermediate energy on the amount of trapped deuterium and the shape of the spectra of the thermal desorption of deuterium in vacuum are studied. Possible mechanisms of these processes are discussed. 相似文献
35.
The isolation of the isoforms of endo- and exochitinases of Clostridium aminovalericum T1 and of the horseradish peroxidase (HRP)-specific immunoglobulin G1 from natural sources by immobilized metal ion affinity chromatography was studied. The effect of Cu2+ and Ni2+ complexes of iminodiacetic acid incorporated in porous glycidyl methacrylate-co-ethylene dimethacrylate and in agarose (Sepharose Fast Flow) beads on separation of the target polypeptides was analyzed. It was found that the Cu2+ complexes bound both the HRP-specific IgG1 and some isoforms of chitinases more strongly than the Ni2+ complexes. From the former complexes, both target polypeptides were eluted by a stepwise imidazole concentration gradient of 5-100 mM. The lower strength of Ni2+ complex binding with the HRP-specific IgG1 resulted in its easy elution with a pH gradient of 5.5-5 while some isoforms of chitinases required imidazole for their elution. The "fraction elution degree" of a target polypeptide (i.e., the ratio of its amounts in each eluate fraction and in the combined fractions) was used for the evaluation of the sorption selectivity and binding affinity of the separating components to the studied metal complexes. 相似文献
36.
E. Yu. Suraeva A. B. Tishchenko M. I. Deryabin A. V. Avdeev 《Russian Physics Journal》2012,54(11):1272-1275
Dependence of the kinetics of sensitized phosphorescence (SP) of 1,3,5-triphenylbenzene (1,3,5-TPB) on the concentration of
the energy donor – benzophenone (BP) – is studied in toluene at 77 K. An increase in the SP decay rate of 1,3,5-TPB with concentration
is established. It is demonstrated that the reason for the increase in the decay rate is the increased radiative deactivation
rate constant of triplet excitations caused by exchange interactions. The coefficient characterizing the exponential dependence
of the radiative deactivation rate constant for triplet excitations of 1,3,5-TPB on the intermolecular distance in the donor-acceptor
pair is determined. 相似文献
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