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131.
Barkovskii Savelii V. Ulitko Maria V. Barkov Alexey Yu. Kochnev Ivan А. Zimnitskiy Nikolay S. Korotaev Vladislav Yu. Sosnovskikh Vyacheslav Ya. Stepanyuk Roman А. Madzhidov Timur I. 《Chemistry of Heterocyclic Compounds》2022,58(8-9):462-472
Chemistry of Heterocyclic Compounds - A method for a regio- and stereoselective synthesis of N-unsubstituted... 相似文献
132.
Vladislav Y. Korotaev Vyacheslav Y. Sosnovskikh Alexey Y. Barkov Pavel A. Slepukhin Yurii V. Shklyaev 《Journal of heterocyclic chemistry》2012,49(4):856-860
Uncatalyzed cycloaddition of 3,4‐dihydroisoquinolines to (E)‐1,1,1‐trifluoro‐3‐nitro‐2‐butene via Grob reaction provide a simple one‐step route to the 5,6‐dihydropyrrolo[2,1‐a]isoquinolines, which represent the basic structural framework of the antitumor active alkaloid crispine. 相似文献
133.
Kapaev Roman Chekannikov Andrey Novikova Svetlana Yaroslavtsev Sergey Kulova Tatiana Rusakov Vyacheslav Skundin Alexander Yaroslavtsev Andrey 《Journal of Solid State Electrochemistry》2017,21(8):2373-2380
Journal of Solid State Electrochemistry - In order to satisfy a growing demand for energy storage devices and to create safer and less expensive batteries with high capacity, materials based on... 相似文献
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We describe families of polynomials arising in the study of the universal central extensions of Lie algebras introduced by Date, Jimbo, Kashiwara, and Miwa (1983) [6] in their work on the Landau–Lifshitz equations. We show these two families of polynomials satisfy certain fourth order linear differential equations by direct computation and one of the families is a particular collection of associated ultraspherical polynomials. 相似文献
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Potential energy surfaces (PES) for rotation about the N-C(sp(3)) or N-C(aryl) bond and energies of stationary points on PES for rotation about the C(sp(2))-N bond are reported for methylthiourea, ethylthiourea, isopropylthiourea, tert-butylthiourea, and phenylurea, using the MP2/aug-cc-pVDZ method. Analysis of alkylthioureas shows that conformations, with alkyl groups cis to the sulfur atom, are more stable (by 0.4-1.5 kcal/mol) than the trans forms. All minima adopt anti configurations with respect to nitrogen pyramidalization, whereas syn configurations are not stationary points on the MP2 potential surface. In contrast, analysis of phenylthiourea reveals that a trans isomer in a syn geometry is the global minimum, whereas a cis isomer in an anti geometry is a local minimum with a relative energy of 2.7 kcal/mol. Rotation about the C(sp(2))-N bond in alkyl and phenyl thioureas is slightly more hindered (9.1-10.2 kcal/mol) than the analogous motion in the unsubstituted molecule (8.6 kcal/mol). The maximum barriers to rotation for the methyl, ethyl, isopropyl, tert-butyl, and phenyl substituents are predicted to be 1.2, 8.9, 8.6, 5.3, and 0.9 kcal/mol, respectively. Corresponding PESs are consistent with the experimental dihedral angle distribution observed in crystal structures. The results of the electronic structure calculations are used to benchmark the performance of the MMFF94 force field. Systematic discrepancies between MMFF94 and MP2 results were improved by modification of selected torsion parameters and one of the van der Waals parameters for sulfur. 相似文献