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排序方式: 共有338条查询结果,搜索用时 593 毫秒
91.
Okamoto Y Yokota M Kawazoe S Kubota H Nagaoka H Arakida Y Takeuchi M 《Chemical & pharmaceutical bulletin》2006,54(5):603-610
To discover an orally active thromboxane A(2) (TXA(2)) and leukotriene D(4) (LTD(4)) dual antagonist, we designed and synthesized chloroquinolylvinyl derivatives based on the structures of the TXA(2) antagonist daltroban and the LTD(4) antagonist montelukast. Among these derivatives, 4-{[(2-(4-chlorophenylsulfonylamino)-1-{3-[(E)-2-(7-chloro-2-quinolyl)vinyl]phenyl}ethyl)thio]methyl}benzoic acid (18d) showed potent inhibitory activity against U46619-induced aggregation of guinea pig platelets and LTD(4)-induced contraction in the guinea pig ileum, with IC(50) values of 340 nm and 0.40 nm, respectively. Oral administration of 18 d also inhibited both the LTD(4)-induced acceleration of plasma leakage to skin in guinea pig and the U46619-induced increase in airway resistance in guinea pig with ED(50) values of 0.47 mg/kg and 3.3 mg/kg, respectively. 相似文献
92.
Regioselective alkylation of 2-alkyl-5,6,7,8-tetrahydro-3H-cycloheptimidazol-4-one (1) and 2-alkyl-3H-cycloheptimidazol-4-one (2) was investigated. 3-[2'-(1-tert-Butyl-1H-tetrazol-5-yl)biphenyl-4-ylmethyl]-2-propyl-5,6,7,8-tetrahydro-1H-cycloheptimidazol-4-one (6) was preferentially obtained under the conditions by using NaH in DMF or THF. On the other hand, 3-[2'-(1-tert-butyl-1H-tetrazol-5-yl)biphenyl-4-ylmethyl]-2-propyl-5,6,7,8-tetrahydro-3H-cycloheptimidazol-4-one (5), the synthetic intermediate compound of Pratosartan, was obtained selectively in the presence of n-Bu(4)NBr in toluene by using aqueous sodium hydroxide as a base. In this reaction, it was found that the concentration of the alkaline solution influences its regioselectivity. This selectivity was observed even for aldehyde and ester derivatives. 相似文献
93.
The reaction of internal alkynes 1 with CO and pyridin-2-ylmethanol (2) in the presence of Rh(4)(CO)(12) results in a double-hydroesterification leading to 1,4-dicarboxylate esters 3. The reaction does not proceed via two consecutive hydroesterifications of alkynes, but the intermediacy of ketene intermediates is proposed. The coordination of the pyridine nitrogen in 2 to rhodium is essential for the reaction to proceed. [reaction: see text] 相似文献
94.
H. Yokota 《Journal of Number Theory》2010,130(9):2003-2010
Let D=F2+2G be a monic quartic polynomial in Z[x], where . Then for F/G∈Q[x], a necessary and sufficient condition for the solution of the polynomial Pell's equation X2−DY2=1 in Z[x] has been shown. Also, the polynomial Pell's equation X2−DY2=1 has nontrivial solutions X,Y∈Q[x] if and only if the values of period of the continued fraction of are 2, 4, 6, 8, 10, 14, 18, and 22 has been shown. In this paper, for the period of the continued fraction of is 4, we show that the polynomial Pell's equation has no nontrivial solutions X,Y∈Z[x]. 相似文献
95.
Hisayuki Horai Masanori Arita Shigehiko Kanaya Yoshito Nihei Tasuku Ikeda Kazuhiro Suwa Yuya Ojima Kenichi Tanaka Satoshi Tanaka Ken Aoshima Yoshiya Oda Yuji Kakazu Miyako Kusano Takayuki Tohge Fumio Matsuda Yuji Sawada Masami Yokota Hirai Hiroki Nakanishi Kazutaka Ikeda Naoshige Akimoto Takashi Maoka Hiroki Takahashi Takeshi Ara Nozomu Sakurai Hideyuki Suzuki Daisuke Shibata Steffen Neumann Takashi Iida Ken Tanaka Kimito Funatsu Fumito Matsuura Tomoyoshi Soga Ryo Taguchi Kazuki Saito Takaaki Nishioka 《Journal of mass spectrometry : JMS》2010,45(7):703-714
MassBank is the first public repository of mass spectra of small chemical compounds for life sciences (<3000 Da). The database contains 605 electron‐ionization mass spectrometry(EI‐MS), 137 fast atom bombardment MS and 9276 electrospray ionization (ESI)‐MSn data of 2337 authentic compounds of metabolites, 11 545 EI‐MS and 834 other‐MS data of 10 286 volatile natural and synthetic compounds, and 3045 ESI‐MS2 data of 679 synthetic drugs contributed by 16 research groups (January 2010). ESI‐MS2 data were analyzed under nonstandardized, independent experimental conditions. MassBank is a distributed database. Each research group provides data from its own MassBank data servers distributed on the Internet. MassBank users can access either all of the MassBank data or a subset of the data by specifying one or more experimental conditions. In a spectral search to retrieve mass spectra similar to a query mass spectrum, the similarity score is calculated by a weighted cosine correlation in which weighting exponents on peak intensity and the mass‐to‐charge ratio are optimized to the ESI‐MS2 data. MassBank also provides a merged spectrum for each compound prepared by merging the analyzed ESI‐MS2 data on an identical compound under different collision‐induced dissociation conditions. Data merging has significantly improved the precision of the identification of a chemical compound by 21–23% at a similarity score of 0.6. Thus, MassBank is useful for the identification of chemical compounds and the publication of experimental data. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
96.
Yokota Y Miyazaki A Fukui K Enoki T Tamada K Hara M 《The journal of physical chemistry. B》2006,110(41):20401-20408
Electroactive tetrathiafulvalene (TTF)-containing alkanethiol self-assembled monolayers (SAMs) were designed and synthesized to elucidate the relationship between electrochemical responses and film structures. Two TTF derivative molecules having one alkanethiol chain (1) and two alkanethiol chains (2) were utilized to modulate the molecular packing arrangements in the SAMs, and the formation and structure of the SAMs were characterized by surface plasmon resonance spectroscopy (SPR). SPR measurements in various contacting media demonstrated loose packing of SAM 1 and close packing of SAM 2 due to the different space fillings of the molecules. Two successive one-electron redox waves were observed for both SAMs by cyclic voltammetry. The peak widths of the redox waves were strongly dependent on the oxidation states of the TTF moieties, the packing arrangement of the SAMs, and the contacting medium. We found that TTF-based SAMs exhibited collective electrochemical responses induced by dynamic structural changes, depending on the degree of freedom for the component molecules in the SAMs. These results imply that the molecular design, taking into account the electrochemical responses, extends the available range of molecular-based functionalities in TTF-based SAMs. 相似文献
97.
William A. Webb Hisashi Yokota 《Proceedings of the American Mathematical Society》2003,131(4):993-1006
Consider the polynomial Pell's equation , where is a monic polynomial in and . Then for , , and , a necessary and sufficient condition for the polynomial Pell's equation to have a nontrivial solution in is obtained.
98.
Choji Kashima Akira Katoh Yuko Yokota Yoshimari Omote 《Journal of heterocyclic chemistry》1981,18(7):1469-1470
1,4,6-Trisubstituted 3,6-dihydro-2-(1H)pyrimidinones (Ia-d) easily underwent the ring opening reaction with hydroxylamine hydrochloride to afford the oximes (IIa-d) in good yields. In the case of 3,6-dihydro-6-methyl-I-phenyl-2-(1H)pyrimidinone (Ie), 2-anilinobutyronitrile (III) was obtained in addition to the oxime (IIe). Dihydro-2-(1H)pyrimidinone (IV) and -thiones (V and VI) did not undergo the ring opening reaction. 相似文献
99.
Tsutomu Kagiya Masatsune Kondo Kenichi Fukui Hisao Yokota 《Journal of polymer science. Part A, Polymer chemistry》1969,7(10):2793-2803
The γ-ray-induced copolymerization of carbon monoxide with saturated or unsaturated cyclic hydrocarbons, such as cyclohexane, cyclohexene, 4-vinyl-1-cyclohexene, and cyclopentadiene was studied at 30°C. Resinous or powdery polymers were obtained in the copolymerization. The results of elementary analysis, infrared spectra, and NMR spectra showed that copolymers containing ketone and ring structures were produced. The copolymers were confirmed to be partially crystalline by the x-ray diffraction diagram. Further, the influence of the addition of ethylenimine on the copolymerization of carbon monoxide with cyclohexane or cyclohexene was examined. A powdery polymer formed in the copolymerization was concluded to be a terpolymer of carbon monoxide with cyclic hydrocarbon and ethylenimine. On the basis of the experimental results, a mechanism of the copolymerization is proposed. 相似文献
100.
Copper(II) and zinc(II) complexes supported by a popular beta-diketiminate ligand (1(-), 2-mesitylamino-4-mesitylimino-2-pentene), [CuII(1)(AcO)] and [[ZnII(1)]2(mu-MeO)(mu-AcO)], have been demonstrated to undergo an oxidative degradation to give a ketone diimine derivative (2) under aerobic conditions. The crystal structures of the mononuclear copper(II) and dinuclear zinc(II) complexes of the beta-diketiminate ligand as well as the copper(II) complex of the modified ligand have been determined by X-ray crystallographic analysis. Mechanism for the oxidative degradation reaction of the beta-diketiminate ligand is also discussed. 相似文献