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301.
M. A. Bastrakov A. M. Starosotnikov V. V. Kachala E. N. Nesterova S. A. Shevelev 《Russian Chemical Bulletin》2007,56(8):1603-1607
Reaction of different anionic S-nucleophiles with 3-R-2-aryl-4,6-dinitroindoles led to a regiospecific nucleophilic substitution
of the nitro group in position 4 with 6-NO2 group remaining intact. The representatives of some peri-annulated polycyclic systems were synthesized on the basis of the substitution products.
Dedicated to Academician V. A. Tartakovsky in honor of his 75th anniversary.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1543–1547, August, 2007. 相似文献
302.
M. R. Darafsheh Y. Farjami A. R. Ashrafi M. Hamadanian 《Journal of mathematical chemistry》2007,41(3):315-326
The non-rigid molecule group theory (NRG) in which the dynamical symmetry operations are defined as physical operations is
a new field in chemistry. Smeyers and Villa computed the r-NRG of the triple equivalent methyl rotation in pyramidal trimethylamine
with inversion and proved that the r-NRG of this molecule is a group of order 648, containing a subgroup of order 324 without
inversions (see J. Math. Chem. 28(4) (2000) 377–388). In this work, a computational method is described, by means of which it is possible to calculate the
symmetry group of molecules. We study the full non-rigid group (f-NRG) of Sponge and Pina molecules with C
2 and C
i point groups, respectively. It proved that these are groups of order 162 and 13122 with 54 and 3240 conjugacy classes, respectively.
The character tables of these groups are also computed. 相似文献
303.
Joanna Gajewiak 《Tetrahedron letters》2006,47(43):7607-7609
Lysophosphatidic acid (LPA) and phosphatidic acid (PA) are potent bioactive lipid mediators of signal transduction and are inactivated by phosphatases. To obtain receptor-isoform selective ligands with neutral phosphomimetic head groups, we performed the stereoselective synthesis of LPA and PA analogues with trifluoromethanesulfonamide and trifluoromethanesulfonamidoxy moieties replacing the phosphomonoester. 相似文献
304.
Production of submicron-sized multihollow polymer particles by alkali/cooling method 总被引:5,自引:0,他引:5
Submicron-sized styrene-methacrylic acid copolymer particles, which were produced by emulsion copolymerization, were changed to those having multihollow structure by treating stepwise the emulsion as follows. First alkali treatment was carried out at higher temperature than the glass transition temperature and subsequently the emulsion was cooled by keeping it at room temperature. This was named alkali/cooling method. The effects of methacrylic acid content, pH, time and temperature in the alkali treatment on the formation of multihollow structure were clarified.Part CLV of the series Studies on suspension and emulsion 相似文献
305.
A. M. Churakov O. Yu. Smirnov S. L. Ioffe Yu. A. Strelenko V. A. Tartakovsky 《Russian Chemical Bulletin》1994,43(9):1532-1535
2-(tert-Butyl-NNO-azoxy)aniline was prepared by selective reduction of 2-(tert-butyl-NNO-azoxy)nitrobenzene. Its bromination yielded the correspondingpara-bromo- andortho, para-dibromoanilines (3a,b).meta-Bromoanilines (6a,b) were synthesized by selective replacement of theortho-bromine atoms in ortho,para-bromo(tert-butylazoxy)benzenes (5a,b) by ammonia in toluene under pressure.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1620–1623, September, 1994.This work was carried out with the financial support of the Russian Foundation for Basic Research (Project No. 93-03-18461). 相似文献
306.
<正> 可溶性含酚酞侧基聚芳醚酮(PEK-C)是一种新型的具有耐高温、耐水解、耐化学腐蚀、自润滑性能的工程塑料,它具有如下结构: 相似文献
307.
O. N. Litvinenko A. N. Kuznetsov A. V. Olenev B. A. Popovkin 《Russian Chemical Bulletin》2007,56(10):1945-1947
Three new mixed tellurides of nickel and group 13–14 metals Ni3−δMTe2 (M = Sn, In, Ga) were prepared by high-temperature ampoule synthesis and studied by powder X-ray diffraction analysis. The
compound Ni3−δSnTe2 was also studied by single crystal X-ray diffraction analysis. The structural model of this phase and two analogs was described
as consisting of layers with nickel-main group metal bonds confined from the above by tellurium atoms. The van der Waals gap
formed through contacts between the tellurium atoms of neighboring layers is partially occupied by nickel atoms.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1879–1881, October, 2007. 相似文献
308.
Bis‐trimethylamine‐ethynyl‐di‐bis(trifluoromethyl)borane [Me3N(CF3)2BCCB(CF3)2NMe3] ( 1 ) has been prepared from trimethylamine‐ethynyl‐bis(trifluoromethyl)borane, [HCCB(CF3)2NMe3], and dimethylamino‐bis(trifluoromethyl)borane, (CF3)2BNMe2. The structure of 1 has been determined by x‐ray crystallography. In the solid state the molecule possesses crystallographic Ci symmetry. The acetylenic attachment to the boron atom is characterized by a short B–C bond length of 1.565(4) Å and an essentially linear B–C–C′ bond angle of 178.1(4)°. 相似文献
309.
310.
邢凤鸣 《中国科学B辑(英文版)》1991,(11)
It is considered that the early Jinning period granitoids from southern Anhui Province belong to the continental crust transformation (S) type and have their own characteristics which are different from those for general continental crust transformation type granitoids. They were formed at the early stage of the late Proterozoic era when that region was at an island-arc stage of the continental margin environment. By that time the continental crust was just formed and had a nature of juvenile crust. It is this juvenile crust that determined a series of characteristics of that type granitoids and made them a relatively independent rock type. They are the products formed by the continental crust in a certain stage of development. 相似文献