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151.
Maslov Konstantin V. Slabko Oleg Yu. Andin Alexander N. Khudyakova Yuliya V. Kaminsky Vladimir A. 《Chemistry of Heterocyclic Compounds》2019,55(11):1060-1064
Chemistry of Heterocyclic Compounds - The bisulfite adduct, formed upon treatment of (2,2'-methanediyl)biscyclohexanone with aqueos sodium bisulfite solution in the presence of acetic acid,... 相似文献
152.
Vladislav Y. Korotaev Igor B. Kutyashev Alexey Y. Barkov Yuliya S. Rozhkova Irina V. Plekhanova Yurii V. Shklyaev Vyacheslav Y. Sosnovskikh 《Tetrahedron letters》2019,60(32):150916
Ferrocene analogues of pyrrolo[2,1-a]isoquinoline alkaloids, 2-(trifluoromethyl)-5,6-dihydroferroceno[g]indolizine and 6-(trifluoromethyl)-8,9-dihydro-6H-chromeno[4,3-b]ferroceno[g]indolizines, were obtained in 44–65% yield via the Grob reaction between 1-nitro-1-(2,2,2-trifluoroethylidene)alkanes or 3-nitro-2-(trifluoromethyl)-2H-chromenes and 1-alkyl-3,4-dihydroferroceno[c]pyridines in 2-propanol at reflux. 相似文献
153.
Sukhanov Gennady T. Filippova Yuliya V. Sukhanova Anna G. Bagryanskaya Irina Yu. Bosov Konstantin K. 《Chemistry of Heterocyclic Compounds》2019,55(12):1197-1203
Chemistry of Heterocyclic Compounds - 1-(Adamantan-1-yl)-1H-1,2,3-triazoles and a series of 1-(adamantan-1-yl)-3-alkyl-1,2,3-triazolium salts were synthesized by regioselective adamantylation of... 相似文献
154.
Yuliya V. Filippova Anna G. Sukhanova Sergei V. Voitekhovich Vadim E. Matulis Gennady T. Sukhanov Yury V. Grigoriev Oleg A. Ivashkevich 《Journal of heterocyclic chemistry》2012,49(4):965-968
4‐Nitro‐1,2,3‐triazole was found to react with tert‐butanol in concentrated sulfuric acid to yield 1‐tert‐butyl‐4‐nitro‐1,2,3‐triazole as the only reaction product, whereas tert‐butylation and tritylation of 4‐nitro‐1,2,3‐triazole in presence of catalytic amount of sulfuric acid in benzene was found to provide mixtures of isomeric 1‐ and 2‐alkyl‐4‐nitro‐1,2,3‐triazoles with predominance of N2‐alkylated products. A new methodology for preparation of 1‐alkyl‐5‐nitro‐1,2,3‐triazoles from 1‐tert‐butyl‐4‐nitro‐1,2,3‐triazole via exhaustive alkylation followed by removal of tert‐butyl group from intermediate triazolium salts was demonstrated by the example of preparation of 1‐methyl‐5‐nitro‐1,2,3‐triazole. 相似文献
155.
Sterol 14alpha-demethylase as a potential target for antitrypanosomal therapy: enzyme inhibition and parasite cell growth 总被引:1,自引:0,他引:1
Lepesheva GI Ott RD Hargrove TY Kleshchenko YY Schuster I Nes WD Hill GC Villalta F Waterman MR 《Chemistry & biology》2007,14(11):1283-1293
Sterol 14alpha-demethylases (CYP51) serve as primary targets for antifungal drugs, and specific inhibition of CYP51s in protozoan parasites Trypanosoma brucei (TB) and Trypanosoma cruzi (TC) might provide an effective treatment strategy for human trypanosomiases. Primary inhibitor selection is based initially on the cytochrome P450 spectral response to ligand binding. Ligands that demonstrate strongest binding parameters were examined as inhibitors of reconstituted TB and TC CYP51 activity in vitro. Direct correlation between potency of the compounds as CYP51 inhibitors and their antiparasitic effect in TB and TC cells implies essential requirements for endogenous sterol production in both trypanosomes and suggests a lead structure with a defined region most promising for further modifications. The approach developed here can be used for further large-scale search for new CYP51 inhibitors. 相似文献
156.
Enhanced thermodynamic and kinetic stability of calix[4]arene dimers locked in the cone conformation
Vysotsky MO Mogck O Rudzevich Y Shivanyuk A Böhmer V Brody MS Cho YL Rudkevich DM Rebek J 《The Journal of organic chemistry》2004,69(18):6115-6120
Wide rim tetraurea derivatives (2a,b) have been prepared from a calix[4]arene rigidified in the cone conformation by two diethyleneglycol ether bridges between adjacent oxygens. In comparison to the analogous tetraurea derivatives (3a,b) of a tetrapentoxy calix[4]arene, 2a,b show an increased thermodynamic stability in mixtures of CDCl(3) and DMSO-d(6). Their kinetic stability as expressed by the rate of guest exchange (benzene or cyclohexane against the solvent benzene-d(6)) is also strongly increased by factors of 30-38. Noticeable differences for the inclusion of selected guests are found. 相似文献
157.
Olesya A. Krumkacheva Ivan O. Timofeev Larisa V. Politanskaya Yuliya F. Polienko Evgeny V. Tretyakov Olga Yu. Rogozhnikova Dmitry V. Trukhin Victor M. Tormyshev Alexey S. Chubarov Elena G. Bagryanskaya Matvey V. Fedin 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(38):13405-13409
Precise nanoscale distance measurements by pulsed electron paramagnetic resonance (EPR) spectroscopy play a crucial role in structural studies of biomolecules. The properties of the spin labels used in this approach determine the sensitivity limits, attainable distances, and proximity to biological conditions. Herein, we propose and validate the use of photoexcited fullerenes as spin labels for pulsed dipolar (PD) EPR distance measurements. Hyperpolarization and the narrower spectrum of fullerenes compared to other triplets (e.g., porphyrins) boost the sensitivity, and superior relaxation properties allow PD EPR measurements up to a near‐room temperature. This approach is demonstrated using fullerene–nitroxide and fullerene–triarylmethyl pairs, as well as a supramolecular complex of fullerene with nitroxide‐labeled protein. Photoexcited triplet fullerenes can be considered as new spin labels with outstanding spectroscopic properties for future structural studies of biomolecules. 相似文献
158.
Convection of a scalar quantity by a compressible velocity field may give rise to unbounded solutions or nonphysical overshoots at the continuous and discrete level. In this paper, we are concerned with solving continuity equations that govern the evolution of volume fractions in Eulerian models of disperse two-phase flows. An implicit Galerkin finite element approximation is equipped with a flux limiter for the convective terms. The fully multidimensional limiting strategy is based on a flux-corrected transport (FCT) algorithm. This nonlinear high-resolution scheme satisfies a discrete maximum principle for divergence-free velocities and ensures positivity preservation for arbitrary velocity fields. To enforce an upper bound that corresponds to the maximum-packing limit, an FCT-like overshoot limiter is applied to the converged convective fluxes at the end of each time step. This postprocessing step imposes an additional physical constraint on the numerical solution to the unconstrained mathematical model. Numerical results for 2D implosion problems illustrate the performance of the proposed limiting procedure. 相似文献
159.
In this article, for a class of degenerate anisotropic elliptic second-order variational inequalities we give conditions on the right-hand side and the set of constraints under which solutions of the variational inequalities are bounded. Our conditions on the set of constraints admit the consideration of a sufficiently large class of problems with pointwise constraints, and in particular, unilateral and bilateral problems. They also admit the consideration of the Dirichlet problem for the corresponding equations. We provide a series of examples which demonstrate the essentiality of the imposed conditions. In particular, we show that the condition assumed for the right-hand side of the variational inequalities in general is unimprovable in the scale of Lebesgue spaces. 相似文献
160.
A novel and simple design technique for triangular spectrum response of fibre Bragg grating (FBG) is presented based on a linear chirped grating. It is shown that this method is fast and can give a straightforward solution to meet a design target. The numerical simulation examples verified the effectiveness of the design method. A general approach to design for multichannel triangular spectral responses for FBG filters is proposed, which provides a solution that achieves a minimum change of refractive index for the fibre. 相似文献