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41.
L. Ignatovich V. Romanovs I. Shestakova I. Domrachova J. Popelis E. Lukevics 《Chemistry of Heterocyclic Compounds》2009,45(12):1441-1448
New highly cytotoxic 3-aminopropyl derivatives of 2-dimethylsilyl-5-trialkylgermylfuran (IC50 1−3 μg⋅ml−1) have been prepared by hydrosilylation of heterocyclic N-allylamines with the corresponding hydrosilane in the presence of
Speier’s catalyst. The influence of the amine structure and alkyl substituent at the germanium atom on the cytotoxicity has
been investigated. 相似文献
42.
A. Grigorjeva A. Jirgensons I. Domracheva E. Yashchenko I. Shestakova V. Andrianov I. Kalvinsh 《Chemistry of Heterocyclic Compounds》2009,45(2):161-168
The synthesis has been developed for novel potential anticancer agents whose structures contain an aziridine amidoxime group.
The cytotoxic activity of all of the target compounds on different cell lines are given together with the in vitro IC50 and LD50 values found. The most promising anticancer agents were found to be the methyl 4-[1-aziridinyl(hydroxyimino)methyl]benzoate,
1-aziridinyl(2-naphthyl)-methanone oxime, and 1-aziridinyl(2-quinolyl)methanone oxime.
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 203–213, February, 2009. 相似文献
43.
Margarita Popova gnes Szegedi Manuela Oykova Hristina Lazarova Neli Koseva Magdolna R. Mihlyi Pavletta Shestakova 《Molecules (Basel, Switzerland)》2021,26(12)
Mono- and bimetallic Ni-, Ru- and Pt-modified hierarchical ZSM-5 materials were prepared by impregnation technique and characterized by X-ray diffraction (XRD), N2 physisorption, temperature-programmed reduction (TPR–TGA), ATR–FTIR and solid state NMR spectroscopy. Formation of finely dispersed nickel, ruthenium and platinum species was observed on the bimetallic catalysts. It was found that the peculiarity of the used zeolite structure and the modification procedure determine the type of formed metal oxides and their dispersion and reducibility. The samples’ acidity was studied via FTIR spectroscopy of adsorbed pyridine. The changes in the zeolite structure were studied via solid-state NMR spectroscopy. The catalysts were investigated in a gas-phase hydrodeoxygenation, transalkylation and dealkylation reaction of model lignin derivative molecules for phenol production. 相似文献
44.
M. Vorona I. Potoročina G. Veinberg I. Shestakova I. Kanepe M. Petrova E. Liepinsh E. Lukevics 《Chemistry of Heterocyclic Compounds》2007,43(5):646-652
The reaction of tert-butyl 7α-chloro-and 7-β-chloro-7α-isopropoxy-3-methyl-1,1-dioxoceph-3-em-4-carboxylates with the Vilsmeier
reagent was carried out with introduction of N,N-dimethylaminomethylene group at position 2 in the E-and Z-isomeric forms.
Prolonged treatment of tert-butyl 7α-chloro-3-methyl-2-(N,N-dimethylaminomethylene)-1,1-dioxoceph-3-em-4-carboxylate with
hydroxylamine hydrochloride in acetonitrile at 40–50°C gave tert-butyl 10(S)-chloro-6-methyl-5-oxa-1,1,9-trioxo-1-thia-4,8-diazatricyclo[7,2,0,02,6]undecane-7(R)-carboxylate which isomerized into 1-tertbutoxycarbonylmethyl-3α-chloro-4-(5-methylisoxazole-4-sulfonyl)azetidin-2-one.
In the case of tertbutyl 7β-chloro-7α-isopropoxy-3-methyl-2-(N,N-dimethylaminomethylen)-1,1-dioxoceph-3-em-4-carboxylate the
analogous reaction gave tert-butyl 10β-chloro-(2S,6S,7S,10R,11R)-10α-isopropoxy-6-methyl-5-oxa-1,1,9-trioxo-1-thia-4,8-diazatricyclo[7,2,0,02,6]undecane-7(R)-carboxylate, the struc-ture of which was determined by 2D-NOESY two-dimensional spectroscopy. The compounds
synthesized showed weak or no cytotoxic activity with respect to monolayers of cancer cells in vitro. 相似文献
45.
E. Lukevics I. Shestakova I. Domracheva A. Nesterova D. Zaruma J. Ashaks 《Chemistry of Heterocyclic Compounds》2006,42(6):761-764
High cytotoxicity has been established for the 8-quinolinethiolates of copper, cadmium, indium, antimony, bismuth, ruthenium,
rhodium, palladium, osmium, iridium, and platinum on HT-1080 (human fibrosarcoma), MG-22A (mouse hepatoma), and B-16 (mouse
melanoma) tumor cells. The greatest activity against HT-1080 was possessed by the iridium complex, and against MG-22A by the
osmium complex. All the investigated metal 8-quinolinethiolates were highly toxic in relation to NIH 3T3 normal mouse embryo
fibroblasts.
__________
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 870–873, June, 2006. 相似文献
46.
Yana Nikolova Georgi M. Dobrikov Zhanina Petkova Pavletta Shestakova 《Molecules (Basel, Switzerland)》2021,26(22)
A series of squaric acid amides (synthesized in 66–99% isolated yields) and a set of chiral aminoalcohols were comparatively studied as ligands in a model reaction of reduction of α-chloroacetophenone with BH3•SMe2. In all cases, the aminoalcohols demonstrated better efficiency (up to 94% ee), while only poor asymmetric induction was achieved with the corresponding squaramides. A mechanistic insight on the in situ formation and stability at room temperature of intermediates generated from ligands and borane as possible precursors of the oxazaborolidine-based catalytic system has been obtained by 1H DOSY and multinuclear 1D and 2D (1H, 10/11B, 13C, 15N) NMR spectroscopy of equimolar mixtures of borane and selected ligands. These results contribute to better understanding the complexity of the processes occurring in the reaction mixture prior to the possible oxazaborolidine formation, which play a crucial role on the degree of enantioselectivity achieved in the borane reduction of α-chloroacetophenone. 相似文献
47.
Large-scale helical-vortex instability is simulated numerically for laminar convection regimes. The simulation is based on the nonlinear Boussinesq equations supplemented by an external force of special form, whose structure is identical to the tensor structure of the generative term in the equation for the hydrodynamic alpha-effect. Introducing the external force makes it possible to model the average effect produced by small-scale helical turbulence: generation of a positive feedback between the toroidal and poloidal components of the velocity vector field. The structure and energetics of helical-vortex flows developing in a convectively unstable medium are analyzed. The parameters of helical and non-helical convection regimes are compared. Certain novel effects related to spiral feedback are discussed: generation of a toroidal velocity field in structures with the poloidal circulation typical of ordinary convection; enlargement of the horizontal scale of supercritical motions as a result of the merging of vortex cells, accompanied by a significant increase in the circulation strength in the larger helical vortices formed; qualitative changes in the energetics. 相似文献
48.
49.
50.
The frequency conditions for absolute stability of a number of nonlinear automatic systems with double modulation (with double pulse modulation, and with pulse and continuous modulation) are established. These conditions are expressed directly in terms of the frequency responses of the linear part.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 15, No. 3, pp. 376–388, March, 1972. 相似文献