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1.
Jia‐Yuh Sheu Yeh‐Long Chen Cherng‐Chyi Tzeng Shu‐Lin Hsu Kuo‐Chang Fang Tai‐Chi Wang 《Helvetica chimica acta》2003,86(7):2481-2489
Certain 1‐ethyl‐ and 1‐aryl‐6‐fluoro‐1,4‐dihydroquinol‐4‐one derivatives were synthesized and evaluated for antimycobacterial and cytotoxic activities. Preliminary results indicated that, for 1‐aryl‐6‐fluoroquinolones, both 7‐(piperazin‐1‐yl)‐ and 7‐(4‐methylpiperazin‐1‐yl) derivatives, 9b and 11a , are able to completely inhibit the growth of M. tuberculosis at a concentration of 6.25 μg/ml, while the 7‐[4‐(2‐oxo‐2‐phenylethyl)piperazin‐1‐yl] derivative 13 exhibits only 31% growth inhibition at the same concentration. For 1‐ethyl‐6‐fluoroquinolones, both 7‐[4‐(2‐oxopropyl)piperazin‐1‐yl]‐ and 7‐[4‐(2‐oxo‐2‐phenylethyl)piperazin‐1‐yl]‐derivatives, 2a and 2b , respectively, show complete inhibition, while their 2‐iminoethyl and substituted phenyl counterparts 3a and 2c are less active. In addition, the 6,8‐difluoro derivative was a more‐favorable inhibitor than its 6‐fluoro counterpart ( 2b vs. 2d ). These results deserve full attention especially because 2a, 2b, 9b , and 11a are non‐cytotoxic at a concentration of 100 μM . Furthermore, compound 9b proved to be a potent anti‐TB agent with selective index (SI)>40 and an EC90 value of 5.75 μg/ml. 相似文献
2.
The focal point of our discussion is the examination of truncated basis sets used in obtaining an accurate first principles clculation of the effective valence shell Hamiltonian by the canonical transformation-cluster expansion approasch. Subsequent diagonalization of this effecitve valence shell hamiltonian yields the valence shell transition energies. A detailed analysis of numerical results obtained using a number of different basis sets of hydrogen-like orbitals together with rigorous symmetry arguments celarly demonstrates the special role played by d orbitals in computing the 3P → 1D transition energy in carbon. The failure of early attempts to calculate the effective Hamiltonian for ethylene from first principles is examined in the light of recent ab initio calculations on ethylene involving d orbitals and the computations reported in this paper. We conclude that accurate calculations of the effective valence shell Hamiltonian for molecules must consider d orbitals in the excited orbital basis set. 相似文献
3.
The reaction of Co(NO3)2·6H2O with two equivalents of PPz (PPz = piperazine hexahydrate) and two equivalents of NH4SCN in CH3OH afforded the complex [Co(NCS)2(PPz)2(CH3OH)2]. The reaction of Ni(NO3)2·6H2O with two equivalents of PPz and four equivalents of NH4SCN in CH3OH afforded the complex [Ni(NCS)4(PPz)2]. Their IR spectra have been recorded and the structures have been determined. Crystal data for 1 : space group P&1bar;, a = 6.7208(6) Å, b = 8.4310(8) Å, c = 8.5923(8) Å, a = 77.881(2)°, β = 76.342(2)°, γ = 83.936(2)°, V = 461.75(1) Å3, Z = 1 with final residuals R1 = 0.0650 and wR2 = 0.1725. Crystal data for 2 : space group P2(1)/n, a = 7.4209(6) Å, b = 11.0231(9) Å, c = 12.317(1) Å, β = 96.642(9)°, V = 1000.9(2) Å3, Z = 2 with final residuals R1 = 0.0378 and wR2 = 0.0809. Important NCS—H‐N and O‐H—N(PPz) hydrogen‐bonding interactions in compound 1 and NCS···H‐N hydrogen‐bonding interactions and NCS—SCN interactions in compound 2 play a significant role in aligning the polymer strands in crystalline solids. 相似文献
4.
Shieh M Cherng JJ Lai YW Ueng CH Peng SM Liu YH 《Chemistry (Weinheim an der Bergstrasse, Germany)》2002,8(19):4522-4527
We have discovered a series of novel pentacarbonylchromium derivatives of bismuth from the reactions of NaBiO(3) with [Cr(CO)(6)] in KOH/MeOH solutions. When the reaction was carried out at room temperature, the highly charged [Bi[Cr(CO)(5)](4)](3-) (1) was obtained, whose structure was shown by X-ray analysis to possess a central bismuth atom tetrahedrally coordinated to four [Cr(CO)(5)] groups. As the reaction was heated at 80 degrees C, the methyl-substituted complex [MeBi[Cr(CO)(5)](3)](2-)(2) was obtained, presumably via the CbondO activation of MeOH. Further reactions of 1 with CH(2)Cl(2) or CHtbondCCH(2)Br form the halo-substituted complexes [XBi[Cr(CO)(5)](3)](2-)(X=Cl, 3; Br, 4), respectively. On the other hand, the reactions of 1 with RI (R=Me, Et) led to the formation of the alkyl-substituted complexes [RBi[Cr(CO)(5)](3)](2-)(R=Me, 2; Et). The formation of complexes 1-4 is discussed, presumably via the intermediate bismuthinidene [Bi[Cr(CO)(5)](3)](-) or the trianion [Bi[Cr(CO)(5)](3)](3-). 相似文献
5.
We have synthesized a new series of chromium-group 15 dihydride and hydride complexes [H(2)As(Cr(CO)(5))(2)](-) (1) and [HE(Cr(CO)(5))(3)](2)(-) (E = As, 2a; E = Sb, 2b), which represent the first examples of group 6 complexes containing E-H fragments. The contrasting chemical reactivity of 2a and 2b with organic halogen derivatives is demonstrated. The reaction of 2a with RBr (R = PhCH(2), HC triple bond CCH(2)) produces the RX addition products [(R)(Br)As(Cr(CO)(5))(2)](-) (R = PhCH(2), 3; R = C(3)H(3), 4), while the treatment of 2b with RX (RX = PhCH(2)Br or HC triple bond CCH(2)Br, CH(3)(CH(2))(5)C(O)Cl) forms the halo-substituted complexes [XSb(Cr(CO)(5))(3)](2-) (X = Br, 5; X = Cl, 6). Moreover, the dihaloantimony complexes [XX'Sb(Cr(CO)(5))(2)](-) can be obtained from the reaction of 2b with the appropriate organic halides. In this study, a series of organoarsenic and antimony chromium carbonyl complexes have been synthesized and structurally characterized and the role of the main group on the formation of the resultant complexes is also discussed. 相似文献
6.
Yeh‐Long Chen Po‐Hsu Chen Chao‐Ho Chung Kuang‐Chieh Li Haw‐Yaun Jeng Cherng‐Chyi Tzeng 《Helvetica chimica acta》2003,86(3):778-786
2‐(Aryloxymethyl)‐5‐benzyloxy‐1‐methyl‐1H‐pyridin‐4‐ones 8a – 8g , 2‐(aryloxymethyl)‐5‐hydroxy‐4H‐pyran‐4‐ones 9a – 9g , and 2‐(aryloxymethyl)‐5‐hydroxy‐1‐methyl‐1H‐pyridin‐4‐ones 10a – 10g were prepared from the known 5‐benzyloxy‐2‐(hydroxymethyl)pyran‐4‐one ( 3 ) in a good overall yield. These compounds were evaluated in vitro against a three‐cell lines panel consisting of MCF7 (breast), NCI‐H460 (lung), and SF‐268 (CNS), and the active compounds passed on for evaluation in the full panel of 60 human tumor cell lines derived from nine cancer cell types. The results indicated that 5‐hydroxy derivatives are more favorable than their corresponding 5‐benzyloxy precursors ( 10a – 10g vs. 8a – 8g ), and 1‐methyl‐1H‐pyridin‐4‐ones are more favorable than their corresponding pyran‐4(1H)‐ones ( 10a – 10g vs. 9a – 9g ). Among these three types of compounds, 2‐(aryloxymethyl)‐5‐hydroxy‐1‐methyl‐1H‐pyridin‐4‐ones 10a – 10g were the most cytotoxic; they inhibited the growth of almost all the cancer cells tested. On the contrary, compound 8a (a mean GI50=27.8 μM ), 8b (38.5), 8d (11.0), and 8e (30.5) are especially active against the growth of SK‐MEL‐5 (a melanoma cancer cell) with a GI50 of <0.01, 5.65, 0.55, and 0.03 μM , respectively (cf. Table 2). 相似文献
7.
8.
Jie‐Ru Yeh Fu‐Yuan Tseng Je‐Yuan Yeh Jing‐Cherng Tsai Raymond Chien‐Chao Tsiang 《Journal of polymer science. Part A, Polymer chemistry》2010,48(20):4400-4407
An effective method to synthesize directly a hard composite material containing uniformly dispersed nanogold particles chemically bonded with a stereospecific, crystalline polymer matrix has been developed. Syndiotactic polypropylene was synthesized and functionalized to have a hydroxyl terminal group (sPPOH) via a metallocene catalysis with a selective chain transfer. Next, sPPOH was activated to react with ethylene sulfide forming the thiol‐terminated polymer, sPPSH. sPPSH was then chemically bonded to gold nanoparticles (AuNPs) formed in situ via a reduction of HAuCl4. The bonding between thiol and AuNP stabilized the AuNPs and led to the formation of sPPAuNPs composite containing uniformly‐dispersed AuNPs of a 19–40 nm size without noticeable aggregation. Furthermore, the chemical bonding of AuNPs has afforded sPPAuNPs a thermal degradation temperature (TD) 49.4 °C higher than the pristine sPP or sPPOH and 25.7 °C higher than sPPSH without any adverse effect on the crystalline temperature and melting temperature. In addition, the characteristic UV‐Vis absorption wavelength of sPPAuNPs remains the same at various temperatures, thus indicating the independence of optical property on temperature as well as the good thermal stability of the sPPAuNPs composite. 1H NMR, 13C NMR, FESEM, STEM, XPS, TGA and DSC were used to investigate the molecular structure, morphology and thermal properties of the resulting sPPAuNPs nanocomposite. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010 相似文献
9.
Aryne‐Induced Novel Tandem 1,2‐Addition/(3+2) Cycloaddition to Generate Imidazolidines and Pyrrolidines 下载免费PDF全文
Dr. Sharada P. Swain Yi‐Chun Shih Dr. Shwu‐Chen Tsay Joby Jacob Dr. Chun‐Cheng Lin Dr. Kuo Chu Hwang Dr. Jia‐Cherng Horng Prof. Dr. Jih Ru Hwu 《Angewandte Chemie (International ed. in English)》2015,54(34):9926-9930
A new “single‐flask” method was developed for the synthesis of imidazolidines and pyrrolidines with high stereoselectivity. First, a Schiff base was arylated with an aryne. Second, an intramolecular proton transfer took place from the methylene position to the anionic aryne ring. Third, the resultant ylide reacted with a second equivalent of the same Schiff base in situ or an electron‐deficient alkene through a (3+2) cycloaddition. These sequential tandem 1,2‐addition/(3+2) cycloaddition reactions led to the desired heterocycles in 63–88 % yields. 相似文献
10.
Stochastic finite element analysis of non-linear plane trusses 总被引:1,自引:0,他引:1
—This study considers the responses of geometrically and materially non-linear plane trusses under random excitations. The stress-strain law in the inelastic range is based on an explicit differential equation model. After a total Lagrangian finite element discretization, the nodal displacements satisfy a system of stochastic non-linear ordinary differential equations with right-hand-sides given by random functions of time. The exact solution of the above stochastic differential equation is generally difficult to obtain. To seek an approximate solution with good accuracy and reasonable computational effort, the stochastic linearization method is used to find the first and second statistical moments (i.e. the mean vector and the one-time covariance matrix) of the nodal displacements. Results of simple structures under Gaussian white-noise excitation indicate that the proposed method has good accuracy (generally underestimates the r.m.s. stationary response by 5–14%) and requires only a small fraction of the computation time of the time-history Monte-Carlo method. 相似文献