OALib Journal期刊

ISSN: 2333-9721




2019 ( 7 )

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匹配条件: “cross-coupling” ,找到相关结果约6831条。
The Electrokinetic Cross-Coupling Coefficient: Two-Scale Homogenization Approach  [PDF]
Vladimir Shelukhin, Igor Yeltsov, Iliya Paranichev
World Journal of Mechanics (WJM) , 2011, DOI: 10.4236/wjm.2011.13018
Abstract: By the two-scale homogenization approach we justify a two-scale model of ion transport through a layered membrane, with flows being driven by a pressure gradient and an external electrical field. By up-scaling, the electroosmotic flow equations in horizontal thin slits separated by thin solid layers are approximated by a homogenized system of macroscale equations in the form of the Poisson equation for induced vertical electrical field and Onsager's reciprocity relations between global fluxes (hydrodynamic and electric) and forces (horizontal pressure gradient and external electrical field). In addition, the two-scale approach provides macroscopic mobility coefficients in the Onsager relations. On this way, the cross-coupling kinetic coefficient is obtained in a form which does involves the ζ -potential among the data provided the surface current is negligible.
Estratégias para estudo das correla??es de energia livre em acoplamento aril-aril de Suzuki: elucidando ciclos catalíticos através da equa??o de Hammett
Rosa, Gilber Ricardo;
Química Nova , 2012, DOI: 10.1590/S0100-40422012000500034
Abstract: the present work deals with the study of the correlation of free-energy developed in a catalytic system for suzuki coupling, by way of the hammett equation. the system presents ncp pincer palladacycle 1 as a catalyst precursor, which proved to be very efficient in the coupling of various aryl boronic acids with aryl halides in previous studies. thus, the article presented here intends to serve as a support for further investigations and clarifications relating to cross-coupling catalytic cycles.
Rea??es de acoplamento cruzado de organossilanos catalisadas por paládio: aspectos históricos, sintéticos e mecanísticos
Teixeira, Róbson R.;Barbosa, Luiz C. A.;Piló-Veloso, Dorila;
Química Nova , 2007, DOI: 10.1590/S0100-40422007000700038
Abstract: the development of the palladium catalyzed cross-coupling reactions employing organosilicon compounds is described. important synthetic methods utilized to prepare organosilicons and different types of cross-coupling reactions involving these compounds are presented. mechanistic aspects are also discussed.
Cross-Coupling Reaction with Lithium Methyltriolborate
Yasunori Yamamoto,Kazuya Ikizakura,Hajime Ito,Norio Miyaura
Molecules , 2013, DOI: 10.3390/molecules18010430
Abstract: We newly developed lithium methyltriolborate as an air-stable white solid that is convenient to handle. The good performance of this triolborate for metal-catalyzed bond-forming reactions was demonstrated in palladium-catalyzed cross-coupling reactions with haloarenes. Cross-coupling reaction of [MeB(OCH 2) 3CCH 3]Li with aryl halides occurred in the presence of Pd(OAc) 2/RuPhos complex in refluxing MeOH/H 2O and the absence of bases.
Biaryl Product Formation from Cross-coupling in Palladiumcatalyzed Borylation of a Boc Protected Aminobromoquinoline Compound
Hao Fang,Jun Yan,Binghe Wang
Molecules , 2004, DOI: 10.3390/90300178
Abstract: The palladium catalyzed borylation of a Boc protected aminobromoquinoline compound with bis(pinacolato)diboron yielded a biaryl compound, resulting from cross coupling, as the major product, instead of the intended boronate, even though no strong base was used. Such results indicate that under certain conditions and with certain substrates, cross coupling can be a major problem during borylation, leading to unintended consequences.
Pd-Catalyzed Carbonyl Insertion Coupling Reactions of a Hypervalent Iodoheterocycle with Alcohols and Amines
Shengj-Jun Luo,Yong-Xiang Ma,Yong-Min Liang
Molecules , 2005, DOI: 10.3390/10010238
Abstract: The palladium-catalyzed cross-coupling carbonyl insertion reaction between 3,7-bis(N,N-dimethylamino)-10H-dibenz[b,e]iodinium iodide (1) and alcohols or amines 2 is described. Some new amides and esters 3 containing an active iodo functional group have been prepared in 65-91% yields.
Efficient and Simple Synthesis of 6-Aryl-1,4-dimethyl-9H-carbazoles
Anna Caruso,Anne Sophie Voisin-Chiret,Jean-Charles Lancelot,Maria Stefania Sinicropi,Antonio Garofalo,Sylvain Rault
Molecules , 2008, DOI: 10.3390/molecules13061312
Abstract: A synthetic method for the preparation of 6-aryl-1,4-dimethyl-9H-carbazoles involving a palladium catalyzed coupling reaction of 1,4-dimethyl-9H-carbazole-6-boronic acids and (hetero)aryl halides is described.
Cross-Coupling Reactions as Valuable Tool for the Preparation of PET Radiotracers
Marc Pretze,Philipp Gro?e-Gehling,Constantin Mamat
Molecules , 2011, DOI: 10.3390/molecules16021129
Abstract: The increasing application of positron emission tomography (PET) in nuclear medicine has stimulated the extensive development of a multitude of new radiotracers and novel radiolabeling procedures with the most prominent short-lived positron emitters carbon-11 and fluorine-18. Radiolabeling with these radionuclides represents a remarkable challenge. Special attention has to be paid to synthesis time and specific labeling techniques due to the short physical half life of the respective radionuclides 11C (t1/2 = 20.4 min) and 18F (t1/2 = 109.8 min). In the past, numerous transition metal-catalyzed reactions were employed in organic chemistry, even though only a handful of these coupling reactions were adopted in radiochemical practice. Thus, the implementation of modern synthesis methods like cross-coupling reactions offers the possibility to develop a wide variety of novel radiotracers. The introduction of catalysts based on transition metal complexes bears a high potential for rapid, efficient, highly selective and functional group-tolerating incorporation of carbon-11 and fluorine-18 into target molecules. This review deals with design, application and improvement of transition metal-mediated carbon-carbon as well as carbon-heteroatom cross-coupling reactions as a labeling feature with the focus on the preparation of radiolabeled compounds for molecular imaging.
Reusable Polymer-Supported Terpyridine Palladium Complex for Suzuki-Miyaura, Mizoroki-Heck, Sonogashira, and Tsuji-Trost Reaction in Water
Toshimasa Suzuka,Kosuke Kimura,Takuya Nagamine
Polymers , 2011, DOI: 10.3390/polym3010621
Abstract: A novel heterogeneous transition-metal catalyst comprising a polymer-supported terpyridine palladium(II) complex was prepared and found to promote the Suzuki-Miyaura, Mizoroki-Heck, Sonogashira, and Tsuji-Trost, reactions in water under aerobic conditions with a high to excellent yield. The catalyst was recovered by simple filtration and directly reused several times without loss of catalytic activity.
The Suzuki Reaction Applied to the Synthesis of Novel Pyrrolyl and Thiophenyl Indazoles
Antonella Migliorini,Chiara Oliviero,Tecla Gasperi,Maria Antonietta Loreto
Molecules , 2012, DOI: 10.3390/molecules17044508
Abstract: The paper describes the Suzuki cross-coupling of a variety of N and C-3 substituted 5-bromoindazoles with N-Boc-2-pyrrole and 2-thiopheneboronic acids. The reactions, performed in the presence of K2CO3, dimethoxyethane and Pd(dppf)Cl2 as catalyst, gave the corresponding adducts in good yields. The methodology allows the facile production of indazole-based heteroaryl compounds, a unique architectural motif that is ubiquitous in biologically active molecules.

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