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排序方式: 共有7510条查询结果,搜索用时 16 毫秒
941.
A new series of compounds(E)-1-(4-(bis-arylmethyl)piperazin-l-y1)-3-arylprop-2-en-1-one(1a-r),have been synthesized and their structures were confirmed by ESI-MS and 1H NMR.The preliminary pharmacological screening showed that some of these compounds had similar neuroprotective effects with Edaravone. 相似文献
942.
The molecular interactions in the complex formation of two tartaric acid derivatives with di(2-ethylhexyl) phosphoric acid are investigated. The complex formation with a 1:1 stoichiometry between tartaric acid derivatives and D2EHPA can be obtained through UV-Vis titration, NMR chemical shifts and molecular dynamic simulations. Furthermore, the differences of the two complexes on the binding constants and strength of hydrogen bonds can also be determined. Such research will ideally provide insight into ways of regulating the complex forming properties of tartaric acid derivatives for composing or syn- thesizing new chiral resolving agents. 相似文献
943.
Marijana Hranjec Gordana Pavlović Marinela Marinović Grace Karminski-Zamola 《Structural chemistry》2008,19(2):353-359
Substituted 2-(2-pyridin-4-yl-vinyl)-1H-benzimidazole derivatives 2, 3 and 6 were synthesized. 2-(2-Pyridin-4-yl-vinyl)-1H-benzimidazole 2 and 6-methyl-2-(2-pyridin-4-yl-vinyl)-1H-benzimidazole 3 were prepared by condensation reaction from 3-pyridin-4-yl-acrylic acid and corresponding 1,2-phenylenediamines in polyphosporic
acid (PPA). 2,7,11-b-Triaza-benzo[c]fluorene 4 was prepared by photochemical dehydrocyclization reaction of ethanolic solution of 2-(2-pyridin-4-yl-vinyl)-1H-benzimidazole 2. 2-(2-Pyridin-4-yl-vinyl)-3H-benzimidazole-6-carbonitrile 6 was prepared by condensation reaction from 3-pyridin-4-yl-propenal and 4-cyano-1,2-phenylenediamine using p-benzoquinone as oxidants. The structure of novel benzimidazole derivatives has been studied by 1H and 13C NMR, IR, MS, UV/Vis and fluorescence spectroscopy. The structure of 2-(2-pyridin-4-yl-vinyl)-1H-benzimidazole 2 was confirmed by X-ray single crystal structure analysis. The conformation of the molecule is E in regard to substituents position around vinyl double C=C bond. The non-planar molecules are mutually connected via the
N–H···N and C–H···N type of intermolecular hydrogen bonds into infinite chains spreading along y axis. 相似文献
944.
A new electrochemical immunosensor for the detection of α‐1‐fetoprotien (AFP) was developed based on AFP antibody (anti‐AFP)‐functionalized organic/inorganic hybrid nanocomposite membrane. To fabricate such a hybrid composite membrane, 3,4,9,10‐perylenetetracarboxylic acid‐bound thionine molecules (PTCTH) were initially doped into titania colloids (TiO2), and then gold nanoparticles and anti‐AFP were immobilized onto the composite film in turn. Comparison with the electrode fabricated only with thionine not 3,4,9,10‐perylenetetracarboxylic acid, the immunosensor with PTCTH exhibited high sensitivity and fast electron transfer. The presence of gold nanoparticles provided a good microenvironment for the immobilization of biomolecules, enhanced the surface coverage of protein, and improved the sensitivity of the immunosensor. The modified process was characterized by scanning electron microscope (SEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The surface topography of the membrane was investigated by scanning electron microscopy (SEM). Under optimal conditions, the proposed immunosensor exhibited a wide linear range from 2.5 to 200.0 ng/mL towards AFP with a detection limit of 0.5 ng/mL (S/N=3). The stability, reproducibility and precision of the immunosensor were acceptable. Comparison with the conventional enzyme‐linked immunosorbent assay (ELISA), the present method did not require more labeled procedures and washing steps. Significantly, the detection methodology provides a promising approach for other proteins or biosecurities. 相似文献
945.
A synthesis of chiral optically active 3-hydroxyoxindoles with 1,3-disubstituted 2,2-dimethyl-cyclobutane structural fragment
by the Et2NH-catalyzed aldol reaction of indoline-2,3-diones with (−)-(1S,3S)-pinonic acid derivatives is described.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1540–1543, July, 2008. 相似文献
946.
Sharp constants are exhibited in exponential inequalities corresponding to the limiting case of the Sobolev inequalities in
Lorentz-Sobolev spaces of arbitrary order.
相似文献
947.
Shuqin Zhang 《Positivity》2008,12(4):711-724
In this paper, we consider the existence of nonnegative solutions of initial value problem for singular nonlinear fractional
differential equation
where D
s
and D
α are the standard Riemann-Liouville fractional derivatives, , may be change sign, t
r
a : [0,1] → R, 0 ≤ r < s − α, and λ > 0 is a parameter. Our analysis relies on the Schauder fixed point theorem.
相似文献
948.
N.V. Loginova T.V. Koval’chuk N.P. Osipovich G.I. Polozov V.L. Sorokin A.A. Chernyavskaya O.I. Shadyro 《Polyhedron》2008
Co(II) complexes with 4,6-di(tert-butyl)-2-aminophenol (HLI) and 2-anilino-4,6-di(tert-butyl)phenol (HLII) have been synthesized and characterized by means of physico-chemical methods. The compounds HLI and HLII coordinate in their singly deprotonated forms and behave as bidentate O,N-coordinated ligands; their low-spin Co(II) complexes are characterized by CoN2O2 coordination modes and square planar geometry. Both the free ligands and their Co(II) and Cu(II) complexes (we have produced and characterized the latter before) exhibit a pronounced antifungal activity against Aspergillus niger, Fusarium spp., Mucor spp., Penicillium lividum, Botrytis cinerea, Alternaria alternata, Sclerotinia sclerotiorum, Monilia spp., which in a number of cases is comparable with that of Nystatin and Terbinafine or even higher. The reducing properties of the ligands and their metal(II) complexes, as well as their antifungal activities, were found to decrease in the order: Cu(LI)2 > Cu(LII)2 ? Co(LI)2 > Co(LII)2 > HLI > HLII. 相似文献
949.
Complete 1H and 13C NMR assignments and Z/E-stereoconfiguration determination for a series of new isomers of 1,4-diketone derivatives obtained via self-sorting tandem reaction were accomplished by means of one- and two-dimentional NMR experiments including 1H, 13C, gCOSY, gHSQC, gHMBC, and NOESY. 相似文献
950.
A moderately thermophilic actinomycete strain, which was identified as Thermoactinomyces strain TA66-2, was isolated from hot-spring water. Fermentation, followed by solvent partition and chromatographic separations, resulted in the isolation of two new and two known molecules. The structures of the new compounds were elucidated as 2-(1-Propionylaminoethyl)thiazole-4-carboxylic acid [2-(1H-indol-3-yl)ethyl]amide and 2-(1-Acetylaminoethyl)thiazole-4-carboxylic acid [2-(1H-indol-3-yl)-ethyl]amide by using spectral methods (1D-, 2D-NMR and LC-ESI-MS). 相似文献