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141.
Lucija Jukić Urška Bratušek Marko Škof Jurij Svete Branko Stanovnik 《Chemistry of Heterocyclic Compounds》1996,32(11-12):1295-1299
A novel approach to the synthesis of 3-acylindolizines and the transformations of some acids into tryptophane analogues are described. Reaction of ethyl 2-pyridinylacetate and methyl 2-quinolinylacetate with N-trifluoroacetyl-5-bromo-4-oxonorvaline methylester led to N-trifluoroacetyl-3-(1-ethoxycarbonylindolizinyl-2) alanine methyl ester and N-trifluoroacetyl-3-(3-methoxycarbonylpyrrolo [1,2-a]quinolinyl-2) alanine methyl ester, respectively. Treatment of ethyl 2-pyridinylacetate and 2-pyridinylacetonitrile, first with N,N-dimethylformamide dimethyl acetal (DMFDMA), followed by reaction with phenacyl bromide, gave the corresponding 3-benzoylindolizines, while the reaction of ethyl 2-pyridinylacetate and 2-pyridinylacetonitrile with DMFDMA, followed by treatment with (S)-N-trifluoroacetyl-5-bromo-4-oxonorvaline methyl ester, gave the corresponding N-trifluoroacetyl-4-oxo-4-(indolizinyl-3)homoalanine methyl esters. 相似文献
142.
143.
Marko D. Mihovilovic Bernhard Müller Markus Spina Arjumand I. Durrani Peter Stanetty Georg Dazinger Karl Kirchner 《Monatshefte für Chemie / Chemical Monthly》2006,137(6):785-794
Summary. Recombinant Escherichia coli overexpressing Pseudomonas sp. NCIMB 9872 cyclopentanone monooxygenase (CPMO, EC 1.14.13.16) and Acinetobacter sp. NCIMB 9871 cyclohexanone monooxygenase (CHMO, EC 1.14.13.22) have been utilized in whole-cell Baeyer-Villiger biotransformations of prochiral bicycloketones. A significant difference in substrate acceptance and stereoselectivity was observed for bicyclo[3.3.0] and bicyclo[4.3.0] substrates. A plausible mechanism of these transformations was established by means of high level DFT/B3LYP calculations suggesting an essential difference in electronic requirements for a successful enzymatic conversion, which was similarly encountered in recombinant whole-cell mediated biooxidations. Some of the lactones produced in the biocatalytic Baeyer-Villiger oxidation represent key intermediates for the synthesis of indole alkaloids. 相似文献
144.
Prehm M Liu F Baumeister U Zeng X Ungar G Tschierske C 《Angewandte Chemie (International ed. in English)》2007,46(42):7972-7975
145.
Nataa Lazi Marko Milivojevi Milan Damnjanovi 《Acta Crystallographica. Section A, Foundations and Advances》2013,69(6):611-619
Spin line groups describe the symmetries of spin arrangements in quasi‐one‐dimensional systems. These groups are derived for the first family of line groups. Among them, magnetic groups are singled out as a special case. Spin arrangements generated by the derived groups are first discussed for single‐orbit systems and then the conclusions are extended to multi‐orbit cases. The results are illustrated by the examples of a CuO2 zigzag chain, a 13C nanotube and the hexaferrite Ba2Mg2Fe12O22. Applications to neutron diffraction and classical ground‐state determination are indicated. 相似文献
146.
147.
Marko V. Jarić 《Physics letters. A》1984,106(4):172-174
The available data for the polymer volume fraction along the coexistence curves for monodisperse solutions of polystyrene in methylcyclohexane are used to derive the exponent z ≈ 0.61 such that the “correct” order parameter is only a function of ?MZ (M is the polymer's molecular weight while ? is the reduced temperature). It is shown that a knowledge of the “correct” order parameter is unnecessary for a determination of z which is expected to be universal, i.e. independent of the polymer-solvent system. 相似文献
148.
In this paper we exhibit a new method of proving non-unitarity of representations, based on semi simplicity of unitarizable
representations. Non-unitarity is proved for a half of all irreducible representations of classical p-adic groups whose infinitesimal character is the same as the infinitesimal character of a generalized Steinberg representation
(as defined in Tadić, Am J Math 120:159–210, 1998). Only the Steinberg representation and its Aubert dual are expected to
be unitary here. In this way we partially generalize a result of Casselman to the case of classical groups. Our argument is
completely different from Casselman’s argument (which is hard to extend to this case). It requires a very limited knowledge
of the inducing cuspidal representation. 相似文献
149.
150.