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941.
942.
943.
Treatment of various acyltrimethylsilanes with vinylmagnesium bromide has allowed a stoichiometric generation of the corresponding 3-(trimethyl-siloxy)allylmagnesiums, which, in the presence of copper(I) trimethylsilyl-acetylide, undergo conjugate addition to several enones to afford the corresponding 1,6-diketone derivatives in good yields. 相似文献
944.
Transmission spectra of powdered ferric borate have been measured in the wave number region from 6000 cm-1 to 30 cm-1 at room and liq. N2 temperatures. Eight absorption bands observed are assigned as three A2u and five Eu phonon modes. Of those modes, the temperature dependence of the Eu mode ar 230 cm-1 (300 K) and the A2u mode at 277 cm-1 (300 K) have been measured in the temperature range containing the Néel temperature. They do not show the influence of magnetic ordering. 相似文献
945.
946.
Yasuhiro Takahashi Isao Sumita Hiroyuki Tadokoro 《Journal of Polymer Science.Polymer Physics》1973,11(11):2113-2122
A new crystal modification was found in poly(ethylene oxide) stretched about two-fold after necking at room temperature. An x-ray diffraction analysis indicated that the planar zigzag molecule passes through a triclinic unit cell with parameters α = 4.71 Å, b = 4.44 Å, c (fiber axis) = 7.12 Å, α = 62.8°, β = 93.2°, and γ = 111.4°. The space group is P1 ?Ci1. Packing of the molecule is very similar to that of monoclinic polyethylene. 相似文献
947.
948.
Yamada J Toita T Akutsu H Nakatsuji S Nishikawa H Ikemoto I Kikuchi K Choi ES Graf D Brooks JS 《Chemical communications (Cambridge, England)》2003,(17):2230-2231
The preparation, crystal structure and physical properties of beta-(BDA-TTP)2GaCl4 has been investigated; the salt exhibits superconductivity at 3.1 K (onset) under a hydrostatic pressure of 7.6 kbar. 相似文献
949.
The reactivity of the reduced anthracene complex of scandium [Li(thf)3][Sc{N(tBu)Xy}2(anth)] ( 2-anth-Li ) (Xy=3,5-Me2C6H3; anth=C14H102−, thf=tetrahydrofuran) toward Brønsted acid [NEt3H][BPh4] and azobenzene is reported. While a stepwise protonation of 2-anth-Li with two equivalents of [NEt3H][BPh4] afforded the scandium cation [Sc{N(tBu)Xy}2(thf)2][BPh4] ( 3 ), reduction of azobenzene gave a thermolabile, anionic scandium reduced azobenzene complex [Li(thf)][Sc{N(tBu)Xy}2(η2-PhNNPh)] ( 4 ), which slowly lost one of the anilide ligands to form the neutral scandium azobenzene complex dimer [Sc{N(tBu)Xy}(μ-η2:η2-Ph2N2)]2 ( 5 ). Exposure of 3 to CO2 produced the scandium carbamate complex [Sc{κ2-O2CN(tBu)(Xy)}2][BPh4] ( 6 ) as a result of CO2 insertion into the Sc−N bonds. In an attempt to prepare scandium hydrides, the reaction of 3 with the hydride sources LiAlH4 and Na[BEt3H] led to the terminal aluminum hydride [AlH{N(tBu)Xy}2(thf)] ( 7 ) and the scandium n-butoxide [Sc{N(tBu)(Xy)}2(μ-OnBu)] ( 8 ) after Sc/Al transmetalation and nucleophilic ring-opening of THF, respectively. All reported compounds isolated in moderate to good yields were fully characterized. 相似文献
950.
Polycyclic N‐Heterocyclic Compounds. Part 85: Synthesis and Evaluation of Antiplatelet Aggregation Activity of 2,4‐Disubstituted 5,6‐Dihydro[1]benzazepino[5,4‐d]pyrimidine and Related Compounds
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Kensuke Okuda Ying‐Xue Zhang Takashi Hirota Kenji Sasaki 《Journal of heterocyclic chemistry》2015,52(3):888-895
We have synthesized a large number of tricyclic 2‐substituted 4‐alkylamino‐5,6‐dihydro[1]benzazepino[5,4‐d]pyrimidines as part of our research to develop new effective antiplatelet drugs. A variety of alkyl and aryl groups were used as substituents at the 2‐position. Evaluation of the effects of the newly synthesized compounds on collagen‐induced platelet aggregation revealed several promising antiplatelet candidates with potencies superior to aspirin. 相似文献