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231.
Mary A. Blanchette William Choy Jeffery T. Davis Amy P. Essenfeld Satoru Masamune William R. Roush Toshiya Sakai 《Tetrahedron letters》1984,25(21):2183-2186
A mild olefination procedure, utilizing LiCl and an amine, has been developed for use with base-sensitive aldehydes and phosphonates. 相似文献
232.
A synthesis of the naturally-occurring title compound has been accomplished. It represents the first success in the synthesis of the naturally-occurring cembranolides. 相似文献
233.
Ikeda S Hozumi T Hashimoto K Ohkoshi S 《Dalton transactions (Cambridge, England : 2003)》2005,(12):2120-2123
In this paper, we report the crystal structure and magnetic properties of the cyano-bridged gadolinium-tungstate bimetallic assembly, GdIII(DMF)6[WV(CN)8](DMF =N,N-dimethylformamide). X-Ray single crystal analysis shows that this compound crystallizes in the monoclinic system of space group P2(1)/c with cell constants a= 16.40(2)A, b= 11.08(1)A, c= 21.18(2)A, beta= 91.09(8) degrees, and Z= 4. The crystal consists of one-dimensional linear chains, in which [GdIII(DMF)6]3+ and [WV(CN)8]3- ions are linked in an alternating fashion. The magnetic data show that this compound is a paramagnet with an antiferromagnetic coupling of -0.58 cm-1 between GdIII(S= 7/2) and WV(S= 1/2). 相似文献
234.
As a part of metabolic studies of mosapride ( 1 ), a potential gastroprokinetic agent, the synthesis of 4-chloro-7-ethoxy-2(3H)-benzoxazolone-6-carboxylic acid ( 7 ) as a derivative of 4-amino-5-chloro-2-ethoxy-3-hydroxybenzoic acid ( 6 ), which has served a benzoic acid part of the metabolites 4 and 5 , is described. Treatment of methyl 3-amino-4-substituted amino-5-chloro-2-ethoxybenzoate derivatives 11a-c with sodium nitrate in acidic medium gave the benzotriazole derivatives 13x,y instead of the objective 3-hydroxy counterpart. The synthesis of 7 started from o-vanillin acetate ( 15 ) and proceeded through the intermediates 2-hydroxy-3-methoxy-4-nitrobenzaldehyde ( 18 ), methyl 4-amino-2,3-dihydroxybenzoate ( 23 ), and methyl 7-hydroxy-2(3H)-benzoxazolone-6-carboxylate ( 30 ). Compound 30 was alternatively prepared from 23 via methyl 4-ethoxycarbonylamino-2-ethoxycarbonyloxy-3-hydroxybenzoate ( 29 ), which is the product resulting from the migration of the ethoxycarbonyl group of methyl 4-amino-2,3-diethoxycar-bonyloxybenzoate ( 27 ). 相似文献
235.
Wataru Ninomiya Yasuhiko Tanabe Ken-Ichiro Sotowa Toshiya Yasukawa Shigeru Sugiyama 《Research on Chemical Intermediates》2008,34(8-9):663-668
Dehydrogenation of decalin to naphthalene through tetralin and that of dicyclohexyl to biphenyl through phenylcyclohexane with Pt/C and Pd/C was investigated mainly under the liquid film state, in which the catalyst was just wet but not suspended and covered with a thin film of liquid substrate. To improve the catalytic activities, the effects of the addition of tellurium into Pd/C were investigated to reveal that the combination of tellurium, palladium and conjugated systems produced during the dehydrogenation of cycloalkames was important to the improvement of the activities. 相似文献
236.
Tomohiko Nakajima Tetsuo Tsuchiya Toshiya Kumagai 《Journal of solid state chemistry》2009,182(9):2560-2565
We have studied pulsed laser-induced oxygen deficiencies at rutile TiO2 surfaces. The crystal surface was successfully reduced by excimer laser irradiation, and an oxygen-deficient TiO2−δ layer with 160 nm thickness was formed by means of ArF laser irradiation at 140 mJ/cm2 for 2000 pulses. The TiO2−δ layer fundamentally maintained a rutile structure, though this structure was distorted by many stacking faults caused by the large oxygen deficiency. The electrical resistivity of the obtained TiO2−δ layer exhibited unconventional metallic behavior with hysteresis. A metal–insulator transition occurred at 42 K, and the electrical resistivity exceeded 104 Ω cm below 42 K. This metal–insulator transition could be caused by bipolaronic ordering derived from Ti–Ti pairings that formed along the stacking faults. The constant magnetization behavior observed below 42 K is consistent with the bipolaronic scenario that has been observed previously for Ti4O7. These peculiar electrical properties are strongly linked to the oxygen-deficient crystal structure, which contains many stacking faults formed by instantaneous heating during excimer laser irradiation. 相似文献
237.
White light emitting phosphor RbVO3 films have been successfully fabricated by means of a vacuum ultraviolet (VUV) irradiation using an excimer lamp after spin coating of metal-organic solution onto substrates. The metal-organic carboxylates coated on substrates decomposed and reacted under the VUV irradiation. The metal-organic bonds were efficiently cleaved by the VUV illumination not only in air but also in vacuum, however, there was not a strong driving force for the reaction process to the formation of RbVO3 in the vacuum atmosphere. On the contrary, the reaction and crystallization simultaneously proceeded under photo-chemically produced active oxygen and/or ozone atmospheres due to the VUV illumination in air. The reaction between the photo-activated Rb-O and V-O species could be strongly enhanced by the oxidation atmospheres at the moment of the metal-organic bond cleavage under the VUV irradiation. 相似文献
238.
K.B. Garg Hisashi Hayashi A. Sato T. Azumi Y. Udagawa Kenji Ishii Toshiya Inami T. Chatterji 《Journal of magnetism and magnetic materials》2008
Spin-selected polarized X-ray absorption near-edge structures (SSXANES) at the Mn K-edge from a bilayer La1.2Sr1.65Ca0.15Mn2O7 single crystal have been studied with high resolution, both in the ferromagnetic (15 K) as well as paramagnetic phase (300 K). The orientation-dependent SSXANES spectra show unmistakable temperature dependence as the system makes the ferromagnetic to paramagnetic phase transition. The pre-edge structures are too intense to be ascribed to weak quadrupole transitions and are interpreted in terms of hybridization of Mn 3d orbitals with O2p and Mn 4p orbitals over and above similar onsite hybridization. The results also indicate possible existence of a small local (time-frozen) ferromagnetic ordering in the macroscopically disordered state. Need for further experimental and theoretical work on the SSXANES spectra from the bilayer system is emphasized. 相似文献
239.
Dr. Toyoto Sato Dr. Luke L. Daemen Dr. Yongqiang Cheng Dr. Anibal J. Ramirez-Cuesta Dr. Kazutaka Ikeda Takuma Aoki Dr. Toshiya Otomo Prof. Shin-ichi Orimo 《Chemphyschem》2019,20(10):1392-1397
The hydrogen-release reaction of a complex transition metal hydride, LaMg2NiH7, composed of La3+, 2×Mg2+, [NiH4]4− and 3×H−, was studied by thermal analyses, powder X-ray, and neutron diffraction and inelastic neutron scattering. Upon heating, LaMg2NiH7 released hydrogen at approximately 567 K and decomposed into LaH2−3 and Mg2Ni. Before the reaction, covalently bound hydrogen (Hc°v.) in [NiH4]4− exhibited a larger atomic displacement than H−, although a weakening of the chemical bonds around [NiH4]4− and H− was observed. These results indicate the precursor phenomenon of a hydrogen-release reaction, wherein there is a large atomic displacement of Hc°v. that induces the hydrogen-release reaction rather than H−. As an isothermal reaction, LaMg2NiH7 formed LaMg2NiH2.4 at 503 K in vacuum for 48 h, and LaMg2NiH2.4 reacted with hydrogen to reform LaMg2NiH7 at 473 K under 1 MPa of H2 gas pressure for 10 h. These results revealed that LaMg2NiH7 exhibited partially reversible hydrogen-release and uptake reactions. 相似文献
240.
Toshiya Ohtsuki Satoshi Tanimoto Makoto Sekiyama Akihiro Fujihara Hiroshi Yamamoto 《Physics letters. A》2018,382(22):1456-1459
Numerical simulations of multiplicatively interacting stochastic processes with weighted selections were conducted. A feedback mechanism to control the weight w of selections was proposed. It becomes evident that when w is moderately controlled around 0, such systems spontaneously exhibit the Pareto–Zipf distribution. The simulation results are universal in the sense that microscopic details, such as parameter values and the type of control and weight, are irrelevant. The central ingredient of the Pareto–Zipf law is argued to be the mild control of interactions. 相似文献