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61.
The reaction of B2H4 with acetylene has been studied by the MNDO method. It is shown that the reaction is exothermic and proceeds in two steps. The first step is the formation of a three-center -complex and this is the rate-determining step of the reaction. The second step is the rearrangement of the -complex to the product and this step requires a very small amount of activation energy. The activation barrier for the diboration reaction is 12.8 kcal/mol.The proposed mechanism is significantly different from those proposed earlier and explains all experimental data relating to this reaction. 相似文献
62.
Hiroto Yoshida Yasuhito YamaryoJoji Ohshita Atsutaka Kunai 《Tetrahedron letters》2003,44(8):1541-1544
Base-free oxidative homocoupling reaction of arylboronic esters has been found to proceed using a catalytic amount of a palladium-1,3-bis(diphenylphosphino)propane (DPPP) complex under an oxygen atmosphere, affording a variety of biaryls in modest to excellent yields. Even arylboronic esters bearing a base-sensitive functional group are applicable to the reaction. 相似文献
63.
Summary The -carbonyl substituted vinylphosphonates6–9 were synthesized from the -dicarbonyl compounds2–5 and the methylenbisphosphonate1 by a Horner-Emmons reaction in different yields.
Synthese von Phosphonocarbonylverbindungen durch Horner-Emmons-Reaktion von Methylenbisphosphonsäuretetraethylester
Zusammenfassung Es wurden die -carbonylsubstituierten Vinylphosphonate6–9 mittels Horner-Emmons-Reaktion aus den -Dicarbonylverbindungen2–5 und Methylenbisphosphonat1 in verschiedenen Ausbeuten hergestellt.相似文献
64.
M. M. Krayushkin M. A. Kalik L. G. Vorontsova E. Yu. Zvezdina M. G. Kurella 《Russian Chemical Bulletin》1993,42(7):1204-1208
9-Methyl-3,3a,4,5-tetrahydro-6H-thieno[2,3-b]thiocino[4,5-c]isoxazole and 9-hydroxyimino-2-methyl-7-methylene-6, 7,8,9-tetrahydro-5H-thieno[2,3-b]thiocine have been prepared for the first time by the oxidation of 2--alkenylthio-3-thiophenecarbaldoximes with NaOCl. X-ray structural investigations of thieno[2,3-b]thiocine and 2-homomethallylthio-5-methyl-3-thiophenecarbaldoxime have been carried out.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1262–1266, July, 1993. 相似文献
65.
66.
Henriques ES Floriano WB Reuter N Melo A Brown D Gomes JA Maigret B Nascimento MA Ramos MJ 《Journal of computer-aided molecular design》2001,15(4):309-322
We present the search for a new model of -factor XIIa, a blood coagulation enzyme, with an unknown experimental 3D-structure. We decided to build not one but three different models using different homologous proteins as well as different techniques and different modellers. Additional studies, including extensive molecular dynamics simulations on the solvated state, allowed us to draw several conclusions concerning homology modelling, in general, and -factor XIIa, in particular. 相似文献
67.
有机金属络合物用于高分子富氧膜的研究进展 总被引:2,自引:0,他引:2
本文介绍了能够可逆吸附分子氧的有机金属络合物用于高分子富氧膜的研究进展,以及以双重吸附理论进行的膜的促进输送机理。 相似文献
68.
R. M. Zolotar' A. I. Bykhovets S. N. Sokolov N. V. Kovganko 《Chemistry of Natural Compounds》2002,38(1):66-69
The toxicity of steroids 1-11 for colorado beetle (Leptinotarsa decemlineata Say.) larvae was studied by contact-intestinal treatment. Active insect-growth regulators were found among the studied compounds. 相似文献
69.
The thermal degradation behaviors of some branched and linear polysiloxanes were studied by thermogravimetric (TG) analysis and infrared (IR) spectroscopy, and the effect of phenyl content on the thermal stability of the tested branched polysiloxanes was investigated. The branched polysiloxanes with phenyl obtain higher thermal stability at lower temperature. The degradation residues of the examined branched polysiloxanes at 800 °C are rather high, 65.1-77.6% in N2 and 40.5-66.5% in air, respectively. However, the amount of solid residue increases with decrease in phenyl content in both N2 and air atmospheres. It was found that the thermal stability of the branched polysiloxanes is higher than that of the linear one, which indicated that the branched structure benefits the formation of a crosslink in the solid residue. 相似文献
70.