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991.
992.
Hideyuki Matsumoto Koichi Shono Akira Wada Ikuya Matsubara Hamao Watanabe Yoichiro Nagai 《Journal of organometallic chemistry》1980,199(2):185-193
In the presence of a catalytic amount of tetrakis(triphenylphosphine)palladium(0), chlorodisilanes of type MenSi2Cl6-n (n 0, 2, 3 and 4) add to 1,3-butadienes to give (Z)-1,4-bis(chlorosilyl)but-2-enes. 相似文献
993.
Asymmetric dipolar cycloadditions of a nitrile oxide to the acrylamide derivatives of two new chiral auxiliaries, (R)-2,2-dimethyl-4-phenyloxazolidines and (S,S)-2,2-dimethyl-4,5-diphenylimidazolidine, show satisfactorily high diastereoselectivities (up to 91%). 相似文献
994.
Toshiko Watanabe Chiemi Miyagi Yasuoki Murakami 《Journal of heterocyclic chemistry》1993,30(1):217-224
To confirm the structure of ethyl 9-methoxybenz[f]indole ( 8a ) prepared from ethyl pyrrole-2-carboxylate ( 4 ) via a new synthetic route, the following chemical correlation work was performed. Ethyl 9-methoxybenz[f]in-dole ( 8a ) was converted to 1-benzyl-3-methyl-5,6,7,8-tetrahydrobenz[f]indole ( 25 ), which was alternatively and authentically synthesized from ethyl 3-methylpyrrole-2-carboxylate ( 11 ). On the basis of the established route to the benz[f]indole nucleus, two representative benz[f]indoles, benz[f]indole ( 1 ) and 4,9-dioxobenz[f]indole ( 26 ) were synthesized. 相似文献
995.
[reaction: see text] Quantitative analysis of the transition state (TS) structures of the insertion reactions of 5-X-2-adamantanylidenes (X = H, OH, NH(2), SiMe(3)) into MeOH or cyclohexane revealed that the magnitude of antiperiplanar hyperconjugative stabilization involving the incipient bond effects (the AP effect) decrease at TS, strongly suggesting that the AP effect contributes "net destabilization" of TS (i.e., increase in activation energy), in sharp contrast to the proposals of the Felkin-Anh and the Cieplak models. The equilibrium population between two carbene bridge-flipping proximal-distal conformers was found to be the origin of facial diastereoselection of these carbenes. 相似文献
996.
Isao Kaetsu Fumio Yoshii Yuhei Watanabe 《Journal of polymer science. Part A, Polymer chemistry》1978,16(10):2645-2650
Radiation-induced polymerization of glass-forming monomers such as 2-hydroxyethyl methacrylate and glycidyl methacrylate under high pressure was studied. The glass transition temperature of these monomers was heightened by increased pressure. The temperature dependence of polymerizability showed a characteristic relation; similar to those in supercooled-phase polymerization under normal pressure, that had a maximum at Tv which shifted to higher levels of temperature as well as to Tg under high pressure. Polymerizability in the supercooled state also increased under increased pressure. 相似文献
997.
998.
999.
本文利用一种新的方法-溶剂化金属原子浸渍法制备了Fe/γ-Al_2O_3,Fe/SiO_2,Co/γ-Al_2O_3,Co/SiO_2,Ni/γ-Al_2O_3和Ni/SiO_2六种催化剂。H_2化学吸附,TEM和XRD测定结果表明这些催化剂中Fe,Co,Ni金属颗粒平均直径都小于30A,金属分散度均大于50%。作者研究了Fe/γ-Al_2O_3,Co/γ-Al_2O_3和Ni/γ-Al_2O_3三种催化剂在CO+H_2反应中的催化行为,测定了碳氢产物分布和比催化活性,表明随着H_2/CO比增大和反应温度升高。较高分子量物种产量减少,有利于生成甲烷。催化剂的活性大小次序为Fe>Ni>Co。 相似文献
1000.
Kumagai J Kumada T Watanabe M Miyazaki T 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2000,56(13):2509-2516
Long-lived radicals, produced by gamma-ray irradiation of mammalian cells at room temperature, cause mutation and morphological transformation in the cells. The local environment near the long-lived radicals in irradiated cells was investigated here by the analysis of electron spin echo envelope modulation (ESEEM) spectra. The number of hydrogen (deuterium) atoms surrounding the long-lived radical, which may correspond to the number of water molecules, was estimated roughly as one or two. It is postulated that the long-lived radicals are generated in the interior of biopolymers. The radicals are not produced by the reaction of OH radicals, but mainly by the decomposition of biopolymer which absorbed directly the energy of the ionizing radiation. 相似文献