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排序方式: 共有92条查询结果,搜索用时 31 毫秒
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Francesca Benedini Giorgio Bertolini Francesco Ferrario Angelo Motti Alberto Sala Flavio Somenzi 《Journal of heterocyclic chemistry》1995,32(1):103-107
The preparation and the physico-chemical characterization of 2H-pyrido[2,3-e]-1,3-oxazine-2,4(3H)-diones, 2H-pyrido[4,3-e]-1,3-oxazine-2,4(3H)-diones, 2H-pyrido[4,3-e]-1,3-oxazin-4(3H)-ones, 2H-thieno[2,3-e]-1,3-oxazin-4(3H)-ones and 2H-thieno[3,4-e]-1,3-oxazine-2,4(3H)-diones are reported. 相似文献
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Pineschi M Bertolini F Haak RM Crotti P Macchia F 《Chemical communications (Cambridge, England)》2005,(11):1426-1428
A conceptually new, simple and practical method for the syn-nucleophilic displacement of aryl and vinyl epoxides and aryl aziridines with (substituted) phenols, using aryl borates as activating nucleophiles under neutral conditions, is reported. 相似文献
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Abstract The quaterpolymerization of methylcyclopentadienyl-5-endo-norborn-2-enyl-methane with ethylene, propylene, and either endo- or exo-dicyclopentadiene was studied by using the catalyst system VAcac3-Et2AlCl. The influence of catalyst and polyenes concentrations, catalyst modifiers, and other polymerization parameters on the general properties of quaterpolymers was investigated. The polymers obtained showed a random distribution of the comonomeric units and the ability to covulcanize with 1,4-cis-polyisoprene. 相似文献
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The synthesis of mevinolin-like lactone precursors and the evaluation of their ability in the N-alkylation of N-potassium-phthalimide are reported. 相似文献
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Treatment of molybdenum Fischer carbene complexes with 6-methylene-7-octen-1-yne derivatives at 40 degrees C generates substituted tricyclo[4.3.1.0(1,6)]deca-2,4-dienes in good yield. Pentacarbonyl(butylmethoxycarbene)molybdenum(0) afforded the highest cyclization yields (54%), while the analogous chromium carbene complex gave no reaction. The range of dienyne substrates that participate in this reaction is explored and its mechanism is analyzed and discussed. 相似文献
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D. Bertolini M. Cassettari G. Salvetti E. Tombari S. Veronesi G. Squadrito 《Il Nuovo Cimento D》1992,14(2):199-205
Summary We report here the first observation of the time-dependent heat capacity of water-lysozyme solution. The observed increase
of heat capacity in time occurs independently of the lysozyme concentration and thepH value of the solvent. The time necessary to attain the heat capacity equilibrium value and the amplitude of the effect are
not well reproducible; the former tends to increase with temperature, while the amplitude decreases and practically disappears
about 35°C. Evolution of a spatial order of the proteins in water and/or of water molecules interacting with the proteins
is considered as a possible explanation for the results. The phenomenon promises to be an important tool to study the role
of water in biological organization and activity. 相似文献
10.
The frequency of the v-CO stretching vibration measured by HRELS has been followed as a function of the CO coverage and in the presence of coadsorbed hydrocarbons on the Ni(111) face. The v-CO frequency shifts continuously from 225 meV (1814 cm?1) to 237 meV (1911 cm?1) when the CO coverage increases from 0 to 0.41. Coadsorption of electron donor molecules, such as ethylene and benzene, generates a significant lowering of the v-CO frequency. Results are discussed in terms of the back donation of metallic electrons into the 2π 1 antibonding orbitals of CO, the dipole-dipole coupling and the coordination number of the CO adsorbed molecules. The back donation is found to play the major role in the range of coverage explored but we cannot exclude some contribution of a dipole-dipole coupling effect. 相似文献