Merck
Search Within
Filtros aplicados
Palavra-chave:'gf33789550'
Exibindo 1-30 of 46 resultados for "

gf33789550

" no prazo de Papéis
Kara Strickland et al.
Nature communications, 6, 7343-7343 (2015-06-11)
Replacement of noble metals in catalysts for cathodic oxygen reduction reaction with transition metals mostly create active sites based on a composite of nitrogen-coordinated transition metal in close concert with non-nitrogen-coordinated carbon-embedded metal atom clusters. Here we report a non-platinum
Jean Bouffard et al.
Topics in current chemistry, 292, 231-280 (2010-01-01)
A review is presented of synthetic methods for the preparation of biaryls by the rhodium-catalyzed C-H bond arylation of arenes with aryl halides (C-H/ C-X couplings), arylmetal reagents (C-H/C-M couplings) and arenes (C-H/C-H couplings), with an emphasis on postulated mechanisms
I Haiduc et al.
In vivo (Athens, Greece), 3(4), 285-293 (1989-07-01)
Recent results on the antitumor activity of organometallic compounds of rhodium, iridium, copper and gold are reviewed. Coordination compounds of some organic ligands are also briefly mentioned. The most promising seem to be copper and gold complexes which exhibited remarkable
Rhodium-catalyzed C-C bond formation via heteroatom-directed C-H bond activation.
Denise A Colby et al.
Chemical reviews, 110(2), 624-655 (2009-05-15)
Hua-Dong Xu et al.
Organic letters, 17(1), 66-69 (2014-12-17)
4-N-allylarylpropylamino-1-sulfonyl triazoles are converted to structurally unique benzopyrrolizidinyl sulfonamides in a one-pot operation. Intramolecular capture of rhodium carbene with arylamino nitrogen gives rise to the formation of an ammonium ylide immediate. A [2,3]- or [1,2]-rearrangement occurs to give a 2-allylpyrrolidinyl-2-carbimine
Kazuyuki Sato
Yakugaku zasshi : Journal of the Pharmaceutical Society of Japan, 126(8), 597-605 (2006-08-02)
Novel fluoroalkylated products where a CF(2)COOEt group was introduced at the alpha-position of alpha,beta-unsaturated ketones or the Reformatsky-type products have been obtained selectively by the reaction of BrCF(2)COOEt and alpha,beta-unsaturated ketones with Et(2)Zn in the presence of RhCl(PPh(3))(3) depending on
Andreas Reisch et al.
ACS nano, 9(5), 5104-5116 (2015-04-22)
Ultrasmall polymer nanoparticles are rapidly gaining importance as nanocarriers for drugs and contrast agents. Here, a straightforward modular approach to efficiently loaded and stable sub-20-nm polymer particles is developed. In order to obtain ultrasmall polymer nanoparticles, we investigated the influence
Angela Kaltenbach et al.
Analytical and bioanalytical chemistry, 407(11), 3093-3102 (2014-12-19)
Gravimetrically prepared mono-elemental reference solutions having a well-known mass fraction of approximately 1 g/kg (or a mass concentration of 1 g/L) define the very basis of virtually all measurements in inorganic analysis. Serving as the starting materials of all standard/calibration solutions, they
Guorong Sheng et al.
Organic letters, 16(19), 5096-5099 (2014-09-12)
3-Diazoindolin-2-imines were constructed from indoles and sulfonylazides via an electronically matched 1,3-dipolar cycloaddition and a subsequent dehydroaromatization/ring-opening cascade. The reaction between 3-substituted indoles and sulfonyl azides provided 2-aminoindoles, while 2-substituted indoles furnished 3-aminoindoles. Moreover, 2,3-diaminoindoles could be prepared from the
Songjie Yu et al.
Organic letters, 17(1), 58-61 (2014-12-18)
Rh(III)-catalyzed, chelation-assisted C-H activation and selenylation of arenes has been achieved. Arenes bearing oxime, azo, pyridyl, and N-oxide chelating groups are viable substrates, and electrophilic selenyl chlorides and diselenides are used as selenylating reagents. The catalytic system is highly efficient
Albert Padwa
Chemical Society reviews, 38(11), 3072-3081 (2009-10-23)
In this tutorial review, the rhodium(II)-catalyzed domino reactions of alpha-diazo carbonyl compounds are summarized. The article will emphasize some of the more recent synthetic applications of the rhodium carbenoid cyclization/cycloaddition domino cascade for alkaloid synthesis. The many structurally diverse and
Scott R Pollack et al.
Journal of labelled compounds & radiopharmaceuticals, 58(11-12), 433-441 (2015-09-19)
Omeprazole (Prilosec®) is a selective and irreversible proton pump inhibitor used to treat various medical conditions related to the production of excess stomach acids. It functions by suppressing secretion of those acids. Radiolabeled compounds are commonly employed in the drug
Jing Zheng et al.
Organic letters, 16(13), 3560-3563 (2014-06-25)
A Rh(III)-catalyzed selective coupling of N-methoxy-1H-indole-1-carboxamide and aryl boronic acids is reported. The coupling is mild and efficient toward diverse product formation, with selective C-C and C-C/C-N bond formation. Kinetic isotope effects studies were conducted to reveal a mechanism of
Huw M L Davies et al.
Chemical Society reviews, 36(7), 1109-1119 (2007-06-20)
This tutorial review describes the reactions of the electron-rich heterocycles pyrrole, furan, indole and benzofuran with copper and rhodium carbenoids. Two main reaction pathways are possible, involving either a concerted non-synchronous cyclopropanation or zwitterionic intermediates. A diverse range of products
Pablo E Guzmán et al.
Angewandte Chemie (International ed. in English), 53(48), 13083-13087 (2014-10-01)
A regio-, diastereo-, and enantioselective [4+3] cycloaddition between vinylcarbenes and dienes has been achieved using the dirhodium tetracarboxylate catalyst [Rh2(S-BTPCP)4]. This methodology provides facile access to 1,4-cycloheptadienes that are regioisomers of those formed from the tandem cyclopropanation/Cope rearrangement reaction of
Simone Pollastri et al.
Journal of hazardous materials, 298, 282-293 (2015-06-16)
Although asbestos represents today one of the most harmful contaminant on Earth, in 72% of the countries worldwide only amphiboles are banned while controlled use of chrysotile is allowed. Uncertainty on the potential toxicity of chrysotile is due to the
Yang Chen et al.
Journal of AOAC International, 97(4), 1143-1150 (2014-08-26)
A proficiency test (PT) program for determination of total As in apple juice samples was conducted by the Food Emergency Response Network (FERN) laboratories. An analytical method using inductively coupled plasma (ICP)-MS was validated for this project. The LOD and
Thibault Cavey et al.
Biometals : an international journal on the role of metal ions in biology, biochemistry, and medicine, 28(4), 733-743 (2015-06-05)
Iron is reported to interact with other metals. In addition, it has been shown that genetic background may impact iron metabolism. Our objective was to characterize, in mice of three genetic backgrounds, the links between iron and several non-iron metals.
Organic chemistry. Construction and deconstruction of aldehydes by transfer hydroformylation.
Clark R Landis
Science (New York, N.Y.), 347(6217), 29-30 (2015-01-03)
Jan Meine Ernsting et al.
Magnetic resonance in chemistry : MRC, 42(9), 721-736 (2004-08-13)
Rhodium is used for a number of large processes that rely on homogeneous rhodium-catalyzed reactions, for instance rhodium-catalyzed hydroformylation of alkenes, carbonylation of methanol to acetic acid and hydrodesulfurization of thiophene derivatives (in crude oil). Many laboratory applications in organometallic
Huw M L Davies et al.
Chemical Society reviews, 40(4), 1857-1869 (2011-03-02)
This tutorial review presents a description of the controlling elements of intermolecular C-H functionalization by means of C-H insertion by donor/acceptor rhodium carbenes. These rhodium carbenes, readily derived from the combination of diazo compounds with dirhodium(ii) catalysts, are sufficiently reactive
Ming Zhou et al.
Organic letters, 16(13), 3484-3487 (2014-06-17)
Highly regioselective and enantioselective asymmetric hydrogenation of cyclic dienamides catalyzed by an Rh-DuanPhos complex has been developed, which provides a readily accessible method for the synthesis of chiral cyclic allylic amines in excellent enantioselectivities (up to 99% ee). The products
Feng Shi et al.
Topics in current chemistry, 292, 123-164 (2010-01-01)
The catalytic activation of a C-H bond is a fundamentally important organic transformation. There are now numerous reports of palladium-mediated C-H activation by the through-space interaction of a palladium center with a neighboring C-H bond. This type of C-H activation
N Katsaros et al.
Critical reviews in oncology/hematology, 42(3), 297-308 (2002-06-07)
The antitumor activity of the inorganic complex cis-diammine-dichloroplatinum(II) (cisplatin) led to the development of other types of non-organic cytostatic drugs. Numerous platinum other platinum and non-platinum metal compounds were shown to be effective against animal model tumors as well as
Pablo Etayo et al.
Chemical Society reviews, 42(2), 728-754 (2012-11-08)
During the last few decades, rhodium-catalysed asymmetric hydrogenation of diverse alkene classes has emerged as a powerful synthetic tool in the pharmaceutical industry, contributing to the manufacturing of chiral drugs, recent drug candidates for clinical trials, and major synthetic precursors
Andreja Bakac
Dalton transactions (Cambridge, England : 2003), (13)(13), 1589-1596 (2006-03-21)
In aqueous solutions, as in organic solvents, rhodium hydrides display the chemistry of one of the three limiting forms, i.e. {Rh(I)+ H+}, {Rh(II)+ H.}, and {Rh(III)+ H-}. A number of intermediates and oxidation states have been generated and explored in
Yang Yang et al.
Environmental science & technology, 48(20), 12362-12369 (2014-09-16)
Disinfectants inactivate pathogens in source water; however, they also react with organic matter and bromide/iodide to form disinfection byproducts (DBPs). Although only a few DBP classes have been systematically analyzed for toxicity, iodinated and brominated DBPs tend to be the
Nicolas P E Barry et al.
Chemical Society reviews, 41(8), 3264-3279 (2012-02-07)
This review describes how the incorporation of dicarba-closo-dodecarboranes into half-sandwich complexes of ruthenium, osmium, rhodium and iridium might lead to the development of a new class of compounds with applications in medicine. Such a combination not only has unexplored potential
Vladimir V Grushin
Accounts of chemical research, 43(1), 160-171 (2009-10-01)
Although springing from two established fields, organometallic chemistry and fluorine chemistry, organometallic fluorine chemistry is still in its early stages. However, developments in this area are expected to provide new tools for the synthesis of selectively fluorinated organic compounds that
Dong Jin Lee et al.
Angewandte Chemie (International ed. in English), 54(46), 13715-13718 (2015-09-18)
A new type of intermolecular rhodium(II)-catalyzed [5+3] cycloaddition has been developed. This higher-order cycloaddition between pyridinium zwitterion 1,5-dipole equivalents and enol diazoacetates enables the formation of eight-membered heterocyclic skeletons, which are otherwise difficult to construct. The optimized cycloaddition occurs efficiently under
Página 1 de 2
Página 1 de 2