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21.
22.
Allyl 2-pyridyl sulfide or allyl phenyl sulfone on treatment with n-butyllithium in tetrahyrofuran followed by tri-n-butylstannylmethyl iodide () afforded directly the 1,3-diene in good yield. 相似文献
23.
Knöevenagel-type reaction between diketene and aldehydes proceeded in the presence of Ti(O-i-Pr)4. This reaction proceeded via titanium enolate derived from Ti(O-i-Pr)4 and diketene. As for the stereoselectivity of the products, E-isomers were produced predominantly in the case of aromatic aldehydes. 相似文献
24.
Akhtaruzzaman M Kamata N Nishida J Ando S Tada H Tomura M Yamashita Y 《Chemical communications (Cambridge, England)》2005,(25):3183-3185
Dithiazolylbenzothiadiazoles easily obtained have high electron affinity and the FET device of a trifluoromethylphenyl derivative exhibited a good n-type performance with high electron mobility. 相似文献
25.
Shimizu H Tada N Ikawa R Kume T Sasaki S 《The journal of physical chemistry. B》2005,109(47):22285-22289
Visual observations through a microscope and in situ Raman measurements have been made for single crystalline ethylene hydrate (EH) and binary methane-ethylene hydrate (MEH) at pressures up to 3.7 GPa and room temperature. Both hydrates showed pressure-induced phase transitions at 1.6, 2.0, and 3.0 GPa for EH and at 1.7, 2.1, and 3.3 GPa for MEH. The cubic sI phase of EH and MEH remains stable up to 1.6 and 1.7 GPa, respectively, which are more widely ranging values than the values for the methane hydrate sI phase. In this sI phase of binary MEH, the cage occupancies by methane and ethylene molecules are investigated from Raman spectra. Above P = 3.0 GPa for EH and 3.3 GPa for MEH, they decomposed by associating with the formation of the polyethylene. 相似文献
26.
[reaction: see text] Aminomethano[60]fullerene was synthesized for the first time as a trifluoromethanesulfonic acid salt by applying the Curtius rearrangement of azidocarbonylmethano[60]fullerene as the key reaction. Aminomethano[60]fullerene thus obtained was found to be able to react with various acyl chlorides to afford the corresponding amides. 相似文献
27.
Toshikazu SaitohToshio Suzuki Norihiro OnoderaHideya Sekiguchi Hisahiro HagiwaraTakashi Hoshi 《Tetrahedron letters》2003,44(13):2709-2712
An efficient and versatile method for the stereospecific construction of α,ω-cis- and α,ω-trans-disubstituted eight- and nine-membered cyclic ethers was developed. Cyclization of the hydroxy epoxides promoted by Eu(fod)3 proceeded via an SN2 process and exo mode to provide the corresponding cyclic ethers in excellent yields. 相似文献
28.
Tada H Soejima T Ito S Kobayashi H 《Journal of the American Chemical Society》2004,126(49):15952-15953
We now report photoinduced sulfur desorption from the surfaces of Au nanoparticles loaded on metal oxides. This reaction occurs in water at ordinary temperature and pressure. Nanometer-sized Au particles have been formed on the surfaces of various metal oxides by deposition-precipitation (Au/oxides). Elemental sulfur (S8) is selectively adsorbed on the Au nanoparticle surfaces of Au/oxides in an atomic state at a coverage of (theta) = 1/3 and in both atomic and molecular states at theta > 1/3. Irradiation (lambdaex > 300 nm) of the sulfur adsorbed Au/anatase TiO2 in water has led to reductive desorption of the sulfurs at room temperature. Electrochemical measurements using Au/oxides indicate that the driving force for this reaction is the photoinduced upward shift of Fermi energy of the metal oxide-supported Au nanoprticles. This study will open up a novel and wide application of heterogeneous photocatalysis for thermal catalysts. 相似文献
29.
Oyamatsu D Hirano Y Kanaya N Mase Y Nishizawa M Matsue T 《Bioelectrochemistry (Amsterdam, Netherlands)》2003,60(1-2):115-121
The enzymatic activity of diaphorase (Dp) immobilized on a solid substrate was characterized using a scanning electrochemical microscope (SECM) with shear force feedback to control the substrate-probe distance. The shear force between the substrate and the probe was monitored with a tuning fork-type quartz crystal and used as the feedback control to set the microelectrode probe close to the substrate surface. The sensitivity and the contrast of the SECM image were improved in the constant distance mode (distance, 50 nm) with the shear force feedback compared to the image in the constant height mode without the feedback. By using this system, the SECM and topographic images of the immobilized diaphorase were simultaneously measured. The microelectrode tip used in this study was ground aslant like a syringe needle in order to obtain the shaper topographic images. This shape was also effective for avoiding the interference during the diffusion of the enzyme substrates. 相似文献
30.
Smiles-type free radical rearrangements of arenesulfonates and arenesulfonamides are exploited for synthetic purposes. 4-Substituted benzenesulfonates cause Smiles-type rearrangement only when substituted by an electron withdrawing group. Therefore, ipso-attack by an alkyl radical on arenesulfonates takes place in an electrophilic manner. Arenesulfonamides rearrange only when the amide nitrogen is substituted by an alkoxycarbonyl group, due to the electron withdrawing nature of this group. Sulfonates and the N-ethoxycarbonylsulfonamide derivatives of naphthalene, quinoline, and thiophene cause more rearrangement and show synthetic utility. Aromatic amino acid analogues were synthesized by Smiles-type rearrangement with moderate yields. The radical Smiles-type rearrangement of sulfonate and sulfonamide derivatives can be a useful synthetic route when we understand the electronic character of these reactions. 相似文献