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11.
Guadalupe Alcerreca Rubén Sanabria René Miranda Gabriel Arroyo Joaquín Tamariz Francisco Delgado 《合成通讯》2013,43(7):1295-1301
Several benzaldehydes were condensed with barbituric acid under infrared irradiation, in absence of solvent, affording the corresponding 5-benzylidene barbituric acids. 相似文献
12.
Rubén Sanabria Rafael Herrera Raúl Aguilar Carlos González‐Romero Hugo A. Jiménez‐Vázquez Francisco Delgado Björn C. G. Söderberg Joaquín Tamariz 《Helvetica chimica acta》2008,91(10):1807-1827
The reactivity and selectivity of the the captodative olefins 1‐acylvinyl benzoates 1a – 1f and 3a as heterodienes in hetero‐Diels–Alder reactions in the presence of electron‐rich dienophiles is described. Heterodienes 1 undergo regioselective cycloaddition with the alkyl vinyl etherdienophiles 6a , b and 9 to give the corresponding dihydro‐2H‐pyrans 7, 8 , and 10 under thermal conditions. The reactivity of these cycloadditions depends, to a large extent, on the electronic demand of the substituent in the aroyloxy group of the heterodiene. Frontier‐molecular‐orbital (FMO; ab initio) and density‐functional‐theory (DFT) calculations of the ground and transition states account for the reactivity and regioselectivity observed in these processes. 相似文献
13.
Néstor M. Carballeira David Sanabria Norma L. Ayala Clarisa Cruz 《Tetrahedron letters》2004,45(19):3761-3763
A stereoselective synthesis for the (5Z,9Z)-14-methyl-5,9-pentadecadienoic acid and the monounsaturated analog (Z)-14-methyl-9-pentadecenoic acid was accomplished in six to seven steps where double alkyne coupling was the key step. This synthesis will facilitate the study of the topoisomerase I inhibitory profile of this important class of fatty acids. 相似文献
14.
Cetina C Berman BL Briscoe WJ Cole PL Feldman G Heimberg P Murphy LY Philips SA Sanabria JC Crannell H Longhi A Sober DI Kezerashvili GY 《Physical review letters》2000,84(25):5740-5743
Total photofission cross sections for 238U, 235U, 233U, 237Np, 232Th, and natPb have been measured simultaneously, using tagged photons in the energy range Egamma=0.17-3.84 GeV. This was the first experiment performed using the Photon Tagging Facility in Hall B at Jefferson Lab. Our results show that the photofission cross section for 238U relative to that for 237Np is about 80% over the entire energy range, implying the presence of important processes which compete with fission. If we assume that for 237Np the photofission probability is equal to unity, we observe a significant shadowing effect, starting below 1.5 GeV. 相似文献
15.
C. Carpintero D. Muñoz E. Rosas J. Sanabria O. García 《Mediterranean Journal of Mathematics》2014,11(4):1215-1228
In this paper we show that for a bounded linear operator \({T\in L(X)}\) acting on a Banach space X, the study of generalized Weyl’s theorem for T can be reduced to the study of generalized Weyl’s theorem for some restrictions of T. 相似文献
16.
Two consecutive C-H bond activations at the coordination sphere of Ir transform the commonly employed NHC ligand IMes into the new κ(3)-C fac-coordinating ligand IMes'. The preparation and structure of Ir(III) complexes featuring this ligand together with selected reactions toward small molecules that illustrate their reactivity keys are described. 相似文献
17.
Camilo Sanabria Malagón 《Journal of Algebra》2011,325(1):248-268
Let ? be a meromorphic connection on a vector bundle over a compact Riemann surface Γ. An automorphism is called a symmetry of ? if the pullback bundle and the pullback connection can be identified with ?. We study the symmetries by means of what we call the Fano group; and, under the hypothesis that ? has a unimodular reductive Galois group, we relate the differential Galois group, the Fano group and the symmetries by means of an exact sequence. 相似文献
18.
In this paper, we define and study the notions of Λ I s -sets, Λ I s -closed sets and I-generalized semi-closed (briefly I-gs-closed) sets by using semi-I-open sets in an ideal topological space. Moreover, we present and characterize two new low separation axioms using the above notions. 相似文献
19.
Laura M. Valdivieso Zarate Cesar A. Bravo Sanabria Gustavo E. Ramírez Caballero Fernando Martínez Ortega 《欧洲无机化学杂志》2023,26(33):e202300194
We report a highly selective (100 %) epoxidation of α-pinene and R-carvone using an oxygen atom transfer (OAT) reaction facilitated by a dioxo-Mo complex (Mo(VI)O2Cl2Ln) incorporated into the ligand 5,5’-dicarboxylate-2,2’-bipyridine (bpydc) within a Metal-Organic Framework (MOF) type UiO-67. Photo-stimulated (350 nm) OAT reaction was carried out with oxygen molecular used as the oxidant for 10 h. UiO-67 was synthesized with a mixture of the ligands 2,2′-biphenyl-5,5′-dicarboxylate (bpdc) and 2,2-bipyridine-5,5-dicarboxylate (bpydc) in different molar ratios (67 : 33, 50 : 50, 70 : 30, 0 : 100 bpdc : bpydc) to promote a higher presence of catalytic sites, i. e., the dioxo-Mo complex units. Furthermore, a post-synthetic exchange of Zr for Ti, between 64 : 36 to 78 : 22 Ti : Zr molar ratio, was performed to improve the optical properties of the MOF and promote the photoinduced OAT reaction. The Catalytic system was characterized by FTIR, XRD, 1H NMR, XPS, TGA, N2 adsorption/desorption and UV-Vis-DR. The amount of the epoxide monoterpene is proportional to the number of the dioxomolybdenum(VI) units (MoO2) incorporated in the UiO-67 (Zr/Ti), and the OAT reaction selectivity is due to the absence of the oxygen radicals in the medium of reaction. Besides, The Mo complex exhibited excellent stability after five cycles of use. 相似文献
20.
Carlos M. Sanabria Sandra L. Gmez Alirio Palma Justo Cobo Christopher Glidewell 《Acta Crystallographica. Section C, Structural Chemistry》2010,66(11):o540-o546
(2S*,4R*)‐2‐exo‐(1‐Naphthyl)‐2,3,4,5‐tetrahydro‐1H‐1,4‐epoxy‐1‐benzazepine, C20H17NO, (I), crystallizes with Z′ = 2 in the space group P21; the two independent molecules have the same absolute configuration, although this configuration is indeterminate. The molecules of each type are linked by a combination of C—H...O and C—H...π(arene) hydrogen bonds to form two independent sheets, each containing only one type of molecule. (2SR,4RS)‐7‐Methyl‐2‐exo‐(1‐naphthyl)‐2,3,4,5‐tetrahydro‐1H‐1,4‐epoxy‐1‐benzazepine, C21H19NO, (II), crystallizes as a true racemate in the space group P21/c, and a combination of C—H...N, C—H...O and C—H...π(arene) hydrogen bonds links the molecules into sheets, each containing equal numbers of the two enantiomorphs. (2S*,4R*)‐2‐exo‐(1‐Naphthyl)‐7‐trifluoromethyl‐2,3,4,5‐tetrahydro‐1H‐1,4‐epoxy‐1‐benzazepine, C21H16F3NO2, (III), crystallizes as a single enantiomorph, as for (I), but now with Z′ = 1 in the space group P212121; again, the absolute configuration is indeterminate. A single C—H...π(arene) hydrogen bond links the molecules of (III) into simple chains. (2S,4R)‐8‐Chloro‐9‐methyl‐2‐exo‐(1‐naphthyl)‐2,3,4,5‐tetrahydro‐1H‐1,4‐epoxy‐1‐benzazepine, C21H18ClNO, (IV), crystallizes as a single enantiomorph of well defined configuration, in the space group P212121, where two independent C—H...π(arene) hydrogen bonds link the molecules into a single three‐dimensional framework structure. 相似文献