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991.
Günter Haufe Thomas C. RosenOliver G.J. Meyer R. FröhlichKari Rissanen 《Journal of fluorine chemistry》2002,114(2):189-198
Monofluorinated cyclopropanecarboxylates are available in racemic or optically active form by transition metal-catalyzed reactions of vinylfluorides with diazoacetates. From α-fluorostyrene and tert-butyl diazoacetate in the presence of 2 mol% of an enantiopure bis(oxazoline) copper complex, a 81:19 mixture of tert-butyl trans- and cis-2-fluoro-2-phenylcyclopropanecarboxylates was obtained with high enantiomeric excess (ee) of 93 or 89%, respectively. The corresponding racemic ethylesters were used as starting materials for the synthesis of carboxamides, of the cis- and trans-isomers of analogues of tranylcypromine, an anti-depressive drug and several of its homologous fluorinated cyclopropylmethyl and cyclopropylethyl amines. Corresponding enantiopure cyclopropylmethanols and several of their derivatives were synthesized also. Solid state structures of a selection of these compounds were examined by X-ray crystallography. Particularly, the cis-configurated fluorinated phenylcyclopropane derivatives showed extremely close intermolecular CH?FC contacts. The shortest of such distances (2.17 Å) was found in the N-(4-bromophenyl)carbamate of (1S,2R)-(2-fluoro-2-phenylcyclopropyl)methanol. 相似文献
992.
The gerade states of acetylene at 9-10 eV have been studied by monitoring the C2 emission. Larger Δv2 excitations are seen than previously reported by Ashfold et al. The observed two-photon resonant levels show extensive predissociation. Experimental evidence from the two-color photofragment excitation measurement is given to support the conclusion that the excited-state ethynyl radical and atomic hydrogen are the corresponding predissociation products. Most C2 emissions seen in this work are due to the subsequent photodissociation of the intermediate C2H to C2 (d3Πg). 相似文献
993.
Jaeyoung Chung 《Archiv der Mathematik》2005,85(2):156-160
We consider the D′ Alembert equation in the space of Schwartz distributions and as an application we find the locally integrable solutions of the equation.Received: 22 July 2004; revised: 12 October 2004 相似文献
994.
研究一类由任意有限多个线性子系统组成的切换系统的动态输出反馈H∞控制问题.利用共同Lyapunov函数方法和凸组合技术,给出由矩阵不等式表示的控制器存在的充分条件,并设计了相应的子控制器和切换规则.采用消元法,将该矩阵不等式转化为一组线性矩阵不等式(LMIs).最后给出一个数值仿真实例证明结论的有效性. 相似文献
995.
Detailed procedures (based on the respective patent literature) for the preparation of the broadspectrum fungicide flusilazole (DPX H 6573) on the laboratory scale are described using as the starting material dichloro(chloromethyl)methylsilane [CH3(ClCH2)SiCl2]. In addition, the crystal and molecular structure of flusilazole (determined by means of X-ray diffraction analysis) is described. 相似文献
996.
Peter Smith 《Acta Appl Math》1986,6(3):293-308
The usual notion of a saddle functional in the calculus of variations assumes a vex/concave structure over the product space
of two inner product spaces. Here the ideas extended to include some convexity in both spaces whilst still retaining an overall
saddle property. Dual extremum principles are established for these functionals. Examples include periodic solutions of Duffing's
equation, an iterative scheme and a pair of simultaneous partial differential equations which arise in magnetohydrodynamics. 相似文献
997.
通过引入带参数的指数积分并利用Bernoulli不等式以及改进了的Hlder不等式,对Hardy-Hilbert积分不等式作了有意义改进.特别,当p=2时,得到了经典的Hilbert积分不等式的一个很强的结果. 相似文献
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