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31.
Synthesis and Antimicrobial Activity of Some New N‐substituted‐5‐arylidene‐thiazolidine‐2,4‐diones
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Anca Stana Brînduşa Tiperciuc Mihaela Duma Laurian Vlase Ovidiu Crişan Adrian Pîrnău Ovidiu Oniga 《Journal of heterocyclic chemistry》2014,51(2):411-417
A total of 17 new N‐substituted derivatives ( 2b , 2c , 2d , 2e , 2f , 2g , 2h , 2i , 2j , 2k and 3b , 3c , 3d , 3e , 3f , 3g , 3h ) of 5‐((2‐phenylthiazol‐4‐yl)methylene) thiazolidine‐2,4‐dione ( 2a ) and 5‐(2,6‐dichloro‐ benzylidene)thiazolidine‐2,4‐dione ( 3a ) were synthesized. The structural elucidation of the newly synthesized compounds was based on elemental analysis and spectroscopic data (MS, 1H NMR, 13C NMR), and their antimicrobial activities were assessed in vitro against several strains of Gram‐positive and Gram‐negative bacteria and one fungal strain (Candida albicans) as growth inhibition diameter. Some of them showed modest to good antibacterial activity against Gram‐negative Escherichia coli and Salmonella typhimurium and Gram‐positive Staphylococcus aureus, Bacillus cereus, and Enterococcus fecalis bacterial strains, whereas almost all the compounds were inactive against Listeria monocytogenes. All of the synthesized compounds showed moderate to very good activity against C. albicans. 相似文献
32.
Beleaga A Bojan VR Pöllnitz A Raţ CI Silvestru C 《Dalton transactions (Cambridge, England : 2003)》2011,40(35):8830-8838
The reaction of RH (1) with Hg(OAc)(2), in EtOH, gave the acetate RHgOAc (2) [R = 2,6-[O(CH(2)CH(2))(2)NCH(2)](2)C(6)H(3)]. The corresponding RHgCl (3) was obtained from 2 and LiCl. The reaction of 3 with TeCl(4) (1:1 molar ratio), in anhydrous 1,4-dioxane, resulted in the transfer of the organic ligand from mercury to tellurium and the isolation of the unexpected ionic compounds [RTe](2)[Hg(2)Cl(6)] (4) and [RH(3)][HgCl(4)] (5). The molecular structures of 1-4 and 5·H(2)O were established by single-crystal X-ray diffraction. The acetate 2 and the chloride 3 are monomeric in solid state. In both mercury and tellurium organometallic compounds the organic group acts as an (N,C,N) "pincer" ligand. This coordination pattern provided stability for the rare [RTe](+) cation. Weak cation-anion interactions [Te···Cl 3.869(3) ?] are present between [RTe](+) and the dinuclear anion [Hg(2)Cl(6)](2-) in the crystal of 4. Theoretical calculations with DFT methods were performed for models of 3 and 4. The results show that in the cation of 4 the coordination of the nitrogen atoms play an important role for the stabilization of the structure found in the crystal whereas in 3 the coordination of the nitrogen atoms to the metal centre stabilizes to a less extent the structure found in solid state. 相似文献
33.
Apetrei CL Tuchilus C Aprotosoaie AC Oprea A Malterud KE Miron A 《Molecules (Basel, Switzerland)》2011,16(9):7773-7788
The chemical constituents and biological activity of Pinus cembra L. (Pinaceae), native to the Central European Alps and the Carpathian Mountains, are not well known. The aim of the present work was to examine the phenolic content, antioxidant and antimicrobial effects of hydromethanolic extracts of Pinus cembra L. bark and needles. Bark extract had higher concentrations of total phenolics (299.3 vs. 78.22 mg gallic acid equivalents/g extract), flavonoids (125.3 vs. 19.84 mg catechin equivalents/g extract) and proanthocyanidins (74.3 vs. 12.7 mg cyanidin equivalents/g extract) than needle extract and was more active as a free radical scavenger, reducing agent and antimicrobial agent. The EC?? values in the 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzo-thiazoline-6-sulfonic acid) diammonium salt (ABTS) and reducing power assays were 71.1, 6.3 and 26 mg/mL for bark extract and 186.1, 24 and 104 mg/mL for needle extract, respectively. In addition, needle extract showed ferrous ions chelating effects (EC?? = 1,755 μg/mL). The antimicrobial effects against Staphylococcus aureus, Sarcina lutea, Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa and Candida albicans were assessed by the agar diffusion method. Both extracts (4 mg/well) were active against all the microorganisms tested; bark extract showed higher inhibition on all strains. These results indicate that Pinus cembra L. bark and needles are good sources of phytochemicals with antioxidant and antimicrobial activities. 相似文献
34.
We obtain explicit upper bounds for the number of irreducible factors for a class of polynomials of the form f ○ g, where f,g are polynomials with integer coefficients, in terms of the prime factorization of the leading coefficients of f and g, the degrees of f and g, and the size of coefficients of f. In particular, some irreducibility results are given for this class of compositions of polynomials. 相似文献
35.
Formation of cyclic Amidiniumiodides and -polyiodides from 1,3,5-Trimethyl-hexahydro-1,3,5-triazine and Iodine The reaction of 1,3,5-trimethyl-hexahydro-1,3,5-triazine (CH3NCH2)3 with iodine in the molar ratio (CH3NCH2)3:I2 = 2:1 gives the new compound 1,3,5-trimethyl-tetrahydro-1,3,5-triazinium-iodide C6H14N3I. This iodide adds one mole I2 and forms 1,3,5-trimethyl-tetrahydro-1,3,5-triazinium-triiodide C6H14N3I3. The crystal structure analysis shows a cation, in which two methyl groups and five ring atoms are planar arranged. The third methyl group stands axial to the ring. 1,3,5-Trimethyl-tetrahydro-1,3,5-triazinium-pentaiodide is formed by adding a further mole I2. 相似文献
36.
A. Dagan 《国际流体数值方法杂志》1988,8(8):943-955
A method for computing the drag coefficient of a body in an axially symmetric, steady-state cavitation flow is presented. A ‘vortex ring’ distribution along the wetted body surface and along the cavity interface is assumed. Since the location of the cavitation interface is unknown a priori, an iterative procedure is used, where, for the first stage, an arbitrary cavitation interface is assumed. The flow field is then solved, and by an iterative process the location of the cavitation interface is corrected. Even though the flow field is governed by the linear Laplace equation, strong non-linearity resulting from the kinematic boundary conditions appears along the cavitation interface. An improved numerical scheme for solving the dual Fredholm integral equations is obtained by formulating high-order approximations to the singular integrals in order to reduce the matrix dimensions. Good agreement is found between the numerical results of the present work, experimental results and other solutions. 相似文献
37.
T. Åkesson M.G. Albrow S. Almehed O. Benary H. Bøggild O. Botner H. Brody V. Burkert A. Di Ciaccio D. Cockerill S. Dagan E. Dahl-Jensen I. Dahl-Jensen G. Damgaard W.M. Evans C.W. Fabjan S. Frankel C. Woody 《Nuclear Physics B》1982,209(2):321-335
Calorimeters downstream of the intersection of pα and αα beams in the ISR have been used to study the hadronization of excited nucleons. These data extend and support the conclusions from previous studies of the A-dependence of particle multiplicities in ultrarelativistic p-nucleus collisions, which provided evidence that the proton hadronizes outside the nuclear volume. 相似文献
38.
A. L. S. Angelis J. Antos M. Beaulieu H. Beker G. Briskin J. Bystricky M. -G. Catanesi P. Cerello S. Dagan G. Dellacasa M. Diehl S. Di Liberto B. Dolgoshein M. Esten C. W. Fabjan A. Gaidot M. Gallio P. Giubellino U. Goerlach C. Guerra L. -A. Hamel S. Konovalov I. Kralik G. London F. Martelli J. -P. Martin M. Masera M. -A. Mazzoni F. Meddi M. -T. Muciaccia S. Muraviev A. Nomerotsky Y. Oren J. -P. Pansart G. Poulard L. Ramello L. Riccati G. Rosa L. Sandor M. Sarris E. Scomparin A. Shmeleva S. Simone S. Smirnov P. Taras J. Urban E. Vercellin 《The European Physical Journal C - Particles and Fields》1998,5(1):63-75
Results are presented on and production in p–W and S–W interactions at 200 GeV/c/nucleon measured via the dimuon decay in a large kinematic region. The data are normalized to
the charged particle multiplicity in the same rapidity interval. They have been collected using the HELIOS/3 muon spectrometer
at the CERN SPS. The ratio , where is the relevant resonance branching fraction, increases between proton and sulphur projectiles, and is somewhat enhanced going from peripheral to central
S–W interactions. This results from an increase in the number of produced 's per charged particle. The ratio is measured in different intervals of p and rapidity. It is not clearly dependent on p, but is larger at higher rapidities. production, likewise normalized to charged multiplicity, is significantly lower in S–W compared to p–W interactions.
Received: 27 October 1997 / Revised version: 5 March 1998 / Published online: 13 July 1998 相似文献
39.
40.
Barbero G Freire FC Scalerandi M Alexe-Ionescu AL 《The journal of physical chemistry. B》2006,110(36):17889-17897
We analyze the influence of the adsorption of ions at the interfaces on the transient phenomena occurring in an electrolytic cell submitted to a steplike external voltage. In the limit of small amplitude of the applied voltage, where the equation of the problem can be linearized, we obtain an analytical solution for the bulk and surface densities of ions and for the electrical potential. We also obtain, in this limit, the relaxation time for the transient phenomena. 相似文献