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1.
V. Slavinska Dz. Sile G. Rozenthal G. Maurops J. Popelis M. Katkevich V. Stonkus E. Lukevics 《Chemistry of Heterocyclic Compounds》2006,42(5):570-573
The hydrogenation of ethyl 4-R-2,4-dioxobutyrates (R = phenyl, 2-furyl) at 5% Pt/Al2O3 catalyst, modified with cinchonidine, and at palladium black was investigated. The former had low activity under the conditions
we tested. The main products during the hydrogenation of these compounds at palladium black are ethyl 4-R-2-hydroxy-4-oxobutyrates.
The yield of the phenyl derivative amounts to 68.5%, while the yield of the corresponding 2-furyl derivative amounts to 97%.
In the last case ethyl 2-hydroxy-4-oxo-4-(2-tetrahydrofuryl)butyrate was detected as impurity. The optimum conditions for
the formation of ethyl 2-hydroxy-4-phenylbutyrate (yield 88.2%) were determined.
__________
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 655–659, May, 2006. 相似文献
2.
Triethylbenzylammonium chlorometallates [Et3NCH2Ph][MCln]m? (M = Pt, Pd, Rh, Ir, Fe, Co, Cu, m = 1–3, n = 3–6), polymer-anchored ionic metal complexes [?—CH2PBu3][MCln]n? and some other chlorometallates and complexes of platinum, rhodium, ruthenium and osmium were studied as catalysts in the hydrogermylation of phenylacetylene with triethylgermane. All the complexes containing platinum, palladium and rhodium were found to be effective catalysts. The cis/trans ratio of the products obtained is determined by the metal atom involved and decreases in the following order: Ir > Rh ? Pd > Pt. 相似文献
3.
David E. Edmunds Bohumí r Opic 《Proceedings of the American Mathematical Society》2003,131(3):745-754
We give new characterizations of Lorentz spaces by means of certain quasi-norms which are shown to be equivalent to the classical ones.
4.
Alla Zablotskaya Izolda Segal Mikhail Maiorov Dmitry Zablotsky Anatoly Mishnev Edmunds Lukevics Irina Shestakova Ilona Domracheva 《Journal of magnetism and magnetic materials》2007
Water-soluble double-coated magnetic nanoparticles (NPs) containing cytotoxic decyldimethyl(β-dimethylaminoethoxy)silane methiodide (AA) molecule sorbed at biocompatible magnetic particles, which consist of magnetite pre-coated with oleic acid (OA), have been prepared. X-ray line profile broadening analysis was used for crystallite size determination. The method of magnetogranulometry has been used for determination of diameter of iron oxide magnetic core and magnetic properties of NPs prepared. In vitro cytotoxicity on monolayer tumor cell lines HT-1080 (human fibrosarcoma), MG-22A (mouse hepatoma) and normal mouse fibroblasts (NIH 3T3) has been studied. It was revealed that all the water-based colloidal solutions obtained are non-toxic and possess high NO-induction ability. 相似文献
5.
6.
D.E. Edmunds R. Hurri-Syrjnen 《Journal of Mathematical Analysis and Applications》2005,310(2):424-435
For bounded Lipschitz domains D in it is known that if 1<p<∞, then for all β[0,β0), where β0=p−1>0, there is a constant c<∞ with for all . We show that if D is merely assumed to be a bounded domain in that satisfies a Whitney cube-counting condition with exponent λ and has plump complement, then the same inequality holds with β0 now taken to be . Further, we extend the known results (see [H. Brezis, M. Marcus, Hardy's inequalities revisited, Dedicated to Ennio De Giorgi, Ann. Scuola Norm. Sup. Pisa Cl. Sci. (4) 25 (1997–1998) 217–237; M. Hoffmann-Ostenhof, T. Hoffmann-Ostenhof, A. Laptev, A geometrical version of Hardy's inequality, J. Funct. Anal. 189 (2002) 537–548; J. Tidblom, A geometrical version of Hardy's inequality for W1,p(Ω), Proc. Amer. Math. Soc. 132 (2004) 2265–2271]) concerning the improved Hardy inequality c=c(n,p), by showing that the class of domains for which the inequality holds is larger than that of all bounded convex domains. 相似文献
7.
Irina Iovel Lena Golomba Juris Popelis Alexander Gaukhman Edmunds Lukevics 《应用有机金属化学》2001,15(1):67-74
The conjugate addition of some (hetero)aromatic amides to an α,β‐unsaturated ester (ethyl acrylate) proceeds efficiently in the presence of an equimolar amount of the CsF–Si(OEt)4 system to afford the corresponding ethyl esters of N‐substituted β‐amino acids. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
8.
The addition of triethylsilane to O- and S- heterocyclic Schiff bases in the presence of Rh, Pd, Pt, and Ir complexes has been studied. A series of the corresponding amines has been synthesized using the most active catalysts, which were the dimeric, monovalent complexes [Rh(1,5-cyclooctadiene)Cl]2 and [Pd(allyl)Cl]2. 相似文献
9.
E. Lukevics G. Barbarella P. Arsenyan S. Belyakov O. Pudova 《Chemistry of Heterocyclic Compounds》2000,36(6):630-662
The results of X-ray crystallographic investigations of compounds containing a 2,2-bithienyl fragment are summarized and analyzed. The structural characteristics of unsubstituted bithiophene, 5-monosubstituted, 5,5-, 3,3-, 4,4-, and 3,4-disubstituted, and more highly substituted bithiophenes and also the structure of -conjugated oligothiophene derivatives are considered.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 725–760, June, 2000. 相似文献
10.
I. Iovel L. Golomba J. Popelis S. Grinberga E. Lukevics 《Chemistry of Heterocyclic Compounds》2003,39(1):49-55
The addition of hydrosilanes (HSiEt3, HSiMe2Ph, H2SiPh2) to the CH=N bond of heterocyclic azomethines has been studied in the presence of monovalent complexes of rhodium and palladium. The effect on the reaction of the CF3 group of the aldimines, which were obtained from O-, S-, and N-heteroaromatic aldehydes and 2-trifluoromethylaniline, has been clarified, as were other regularities of the processes being studied. A series of corresponding furans, thiophenes, and pyridine amines has been synthesized. 相似文献