- Cross-Coupling through Ag(I)/Ag(III) Redox Manifold
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In ample variety of transformations, the presence of silver as an additive or co-catalyst is believed to be innocuous for the efficiency of the operating metal catalyst. Even though Ag additives are required often as coupling partners, oxidants or halide scavengers, its role as a catalytically competent species is widely neglected in cross-coupling reactions. Most likely, this is due to the erroneously assumed incapacity of Ag to undergo 2e? redox steps. Definite proof is herein provided for the required elementary steps to accomplish the oxidative trifluoromethylation of arenes through AgI/AgIII redox catalysis (i. e. CEL coupling), namely: i) easy AgI/AgIII 2e? oxidation mediated by air; ii) bpy/phen ligation to AgIII; iii) boron-to-AgIII aryl transfer; and iv) ulterior reductive elimination of benzotrifluorides from an [aryl-AgIII-CF3] fragment. More precisely, an ultimate entry and full characterization of organosilver(III) compounds [K]+[AgIII(CF3)4]? (K-1), [(bpy)AgIII(CF3)3] (2) and [(phen)AgIII(CF3)3] (3), is described. The utility of 3 in cross-coupling has been showcased unambiguously, and a large variety of arylboron compounds was trifluoromethylated via [AgIII(aryl)(CF3)3]? intermediates. This work breaks with old stereotypes and misconceptions regarding the inability of Ag to undergo cross-coupling by itself.
- Demonti, Luca,Mézailles, Nicolas,Nebra, Noel,Saffon-Merceron, Nathalie
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supporting information
p. 15396 - 15405
(2021/10/12)
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- Evaluation of the role of graphene-based Cu(i) catalysts in borylation reactions
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Carbon-supported catalysts have been considered as macromolecular ligands which modulate the activity of the metallic catalytic center. Understanding the properties and the factors that control the interactions between the metal and support allows a fine tuning of the catalyzed processes. Although huge effort has been devoted to comprehending binding energies and charge transfer for single atom noble metals, the interaction of graphenic surfaces with cheap and versatile Cu(i) salts has been scarcely studied. A methodical experimental and theoretical analysis of different carbon-based Cu(i) materials in the context of the development of an efficient, general, scalable, and sustainable borylation reaction of aliphatic and aromatic halides has been performed. We have also examined the effect of microwave (MW) radiation in the preparation of these type of materials using sustainable graphite nanoplatelets (GNP) as a support. A detailed analysis of all the possible species in solution revealed that the catalysis is mainly due to an interesting synergetic Cu2O/graphene performance, which has been corroborated by an extensive theoretical study. We demonstrated through DFT calculations at a high level of theory that graphene enhances the reactivity of the metal in Cu2O against the halide derivative favoring a radical departure from the halogen. Moreover, this material is able to stabilize radical intermediates providing unexpected pathways not observed using homogeneous Cu(i) catalysed reactions. Finally, we proved that other common carbon-based supports like carbon black, graphene oxide and reduced graphene oxide provided poorer results in the borylation process.
- Cid, M. B.,Díaz, Cristina,Franco, Mario,Lamsabhi, Al Mokhtar,Sainz, Raquel,Tortosa, Mariola
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p. 3501 - 3513
(2021/06/06)
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- Competing dehalogenation versus borylation of aryl iodides and bromides under transition-metal-free basic conditions
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In this work, selectivity-controllable base-promoted transition-metal-free borylation and dehalogenation of aryl halides are described. Under the conditions of borylation, the dehalogenation which emerges as a competitive side reaction has been well-controlled by carefully controlling the borylation conditions. On the other hand, the dehalogenation using benzaldehyde as a hydrogen source has also been accomplished. The applications of direct radical borylation and dehalogenation of aryl halides demonstrate their synthetic practicability in pharmaceutical-oriented organic synthesis. Based on the experimental evidences, the tBuOK/1,10-Phen-triggered radical nature of both competitive reactions has been revealed.
- Niu, Yi-Jie,Sui, Guo-Hui,Zheng, Hong-Xing,Shan, Xiang-Huan,Tie, Lin,Fu, Jia-Le,Qu, Jian-Ping,Kang, Yan-Biao
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p. 10805 - 10813
(2019/09/30)
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- Replacement of Stoichiometric DDQ with a Low Potential o-Quinone Catalyst Enabling Aerobic Dehydrogenation of Tertiary Indolines in Pharmaceutical Intermediates
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A transition-metal/quinone complex, [Ru(phd)3]2+ (phd = 1,10-phenanthroline-5,6-dione), is shown to be effective for aerobic dehydrogenation of 3° indolines to the corresponding indoles. The results show how low potential quinones may be tailored to provide a catalytic alternative to stoichiometric DDQ, due to their ability to mediate efficient substrate dehydrogenation while also being compatible with facile reoxidation by O2. The utility of the method is demonstrated in the synthesis of key intermediates to pharmaceutically important molecules.
- Li, Bao,Wendlandt, Alison E.,Stahl, Shannon S.
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supporting information
p. 1176 - 1181
(2019/02/14)
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- Palladium-Catalyzed Decarbonylative Borylation of Carboxylic Acids: Tuning Reaction Selectivity by Computation
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Decarbonylative borylation of carboxylic acids is reported. Carbon electrophiles are generated directly after reagent-enabled decarbonylation of the in situ accessible sterically-hindered acyl derivative of a carboxylic acid under catalyst controlled conditions. The scope and the potential impact of this method are demonstrated in the selective borylation of a variety of aromatics (>50 examples). This strategy was used in the late-stage derivatization of pharmaceuticals and natural products. Computations reveal the mechanistic details of the unprecedented C?O bond activation of carboxylic acids. By circumventing the challenging decarboxylation, this strategy provides a general synthetic platform to access arylpalladium species for a wide array of bond formations from abundant carboxylic acids. The study shows a powerful combination of experiment and computation to predict decarbonylation selectivity.
- Liu, Chengwei,Ji, Chong-Lei,Hong, Xin,Szostak, Michal
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supporting information
p. 16721 - 16726
(2018/11/30)
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- An organic boron compound
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PROBLEM TO BE SOLVED: To provide a production method of an arylboronic acid ester with a wide range of application substrate, using no heavy metal.SOLUTION: An organic halogen compound represented by the general formula R-X (where, X is Br or I; R is a C1 to 20 alkyl group, a C6 to 14 aryl group, a heterocyclic group comprising 1 to 3 hetero atoms selected from N, O and S, or the like) and a compound represented by the general formula (VI) are reacted in the presence of sodium alkoxide or potassium alkoxide for substitution of a substituted Si moiety and the R moiety to obtain arylboronic acid ester. (In the formula, three Rare each independently a C1 to 6 alkyl group or a C6 to 10 aryl group; and four Reach independently a C1 to 3 alkyl group.)
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Paragraph 0072-0074; 0096-0097
(2019/02/20)
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- Synthesis of Unnatural Arundines Using a Magnetically Reusable Copper Ferrite Catalyst
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We report a method for copper ferrite-catalyzed coupling of indoles and N, N -dimethylacetamide (DMA) to afford Arundine derivatives. Halogen, methoxy, boronate ester, and trimethylsilyl functionalities are compatible with reaction conditions. Unprotected or sterically hindered indoles are also competent substrates. Indoles containing competitively reactive pyrazoles deliver the desired products in reasonable yields. The copper ferrite is easily recovered and reused, up to nine times without a significant yield loss.
- Ha, Pha T.,Nguyen, Oanh T. K.,Huynh, Khoa D.,Nguyen, Tung T.,Phan, Nam T. S.
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supporting information
p. 2031 - 2034
(2018/09/18)
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- Efficient Synthesis of Aryl Boronates via Cobalt-Catalyzed Borylation of Aryl Chlorides and Bromides
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An efficient catalytic system based on a Co(II)-NHC precursor has been developed for the cross coupling of bis(pinacolato)diboron with aryl halides including aryl chlorides, affording the aryl boronates in good to excellent yields. A wide range of functional groups are tolerated under mild reaction conditions. The reaction shows excellent chemoselectivity for bromide over chloride. Preliminary mechanistic investigations show that the catalytic cycle may rely on a cobalt(I)-(III) redox couple.
- Verma, Piyush Kumar,Mandal, Souvik,Geetharani
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p. 4049 - 4054
(2018/05/22)
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- Photoinduced Miyaura Borylation by a Rare-Earth-Metal Photoreductant: The Hexachlorocerate(III) Anion
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The first photoinduced carbon(sp2)–heteroatom bond forming reaction by a rare-earth-metal photoreductant, a Miyaura borylation, has been achieved. This simple, scalable, and novel borylation method that makes use of the hexachlorocerate(III) anion ([CeIIICl6]3?, derived from CeCl3) has a broad substrate scope and functional-group tolerance and can be conducted at room temperature. Combined with Suzuki–Miyaura cross-coupling, the method is applicable to the synthesis of various biaryl products, including through the use of aryl chloride substrates.
- Qiao, Yusen,Yang, Qiaomu,Schelter, Eric J.
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supporting information
p. 10999 - 11003
(2018/07/31)
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- Preparation method of benzoheterocyclic boric acid
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The invention provides a preparation method of benzoheterocyclic boric acid. The preparation method comprises steps as follows: (1) a benzoheterocyclic compound shown in a formula I is dissolved in asolvent A, a liquor A is obtained, a boronylation reagent is dissolved in a solvent B, a liquor B is obtained, a palladium catalyst and an alkaline reagent are immobilized on a channel of a continuousflow reactor, the liquor A and the liquor B are subjected to a continuous adding reaction, the reaction is stopped after the mixture flows out of a reaction tube, and an intermediate is obtained; (2)the intermediate obtained in step (1) is subjected to a hydrolysis reaction, and benzoheterocyclic boric acid is obtained. According to the provided preparation method, the benzoheterocyclic boric acid is synthesized with a flow chemical technology. Compared with methods in the prior art, the method has the advantages that the product yield is 86% or above, the highest yield can reach 90% or above, the yield is very high, the reaction rate is high, energy consumption of a reaction is reduced greatly, and the method is high in operability, high in automation degree and favorable for productionoperation and industrial production.
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Paragraph 0056; 0058; 0059
(2018/09/13)
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- Iron-Catalyzed Borylation of Aryl Chlorides in the Presence of Potassium t-Butoxide
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A catalytic amount of an inorganic iron salt such as Fe(acac)3 catalyzes borylation of various aryl and heteroaryl chlorides with bis(pinacolato)diboron, where the presence of potassium t-butoxide is crucially important. The alkoxide is considered to produce in situ an electron-rich iron alkoxide complex as the active species. The reaction requires only an iron salt and potassium t-butoxide as promoters and is easily scalable. The arylboron compound prepared by this reaction can be further coupled in situ with an aryl halide under the Suzuki-Miyaura conditions.
- Yoshida, Takumi,Ilies, Laurean,Nakamura, Eiichi
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p. 3199 - 3203
(2017/06/09)
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- Chiral Pincer Carbodicarbene Ligands for Enantioselective Rhodium-Catalyzed Hydroarylation of Terminal and Internal 1,3-Dienes with Indoles
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Catalytic enantioselective addition of N-heteroarenes to terminal and internal 1,3-dienes is reported. Reactions are promoted by 5 mol % of Rh catalyst supported by a new chiral pincer carbodicarbene ligand that delivers allylic substituted arenes in up to 95% yield and up to 98:2 er. Mechanistic and X-ray evidence is presented that supports that the reaction proceeds via a Rh(III)-η3-allyl.
- Marcum, Justin S.,Roberts, Courtney C.,Manan, Rajith S.,Cervarich, Tia N.,Meek, Simon J.
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supporting information
p. 15580 - 15583
(2017/11/14)
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- Catalytic aromatic borylation via in situ-generated borenium species
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We have developed a catalytic direct borylation of arenes via in situ-generated borenium species. The choice of appropriate Lewis base was crucial to achieve the catalytic system. Electron-rich arenes were borylated in a regioselective manner.
- Kitani, Fumiya,Takita, Ryo,Imahori, Tatsushi,Uchiyama, Masanobu
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p. 158 - 166
(2017/07/28)
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- Chemoselective coupling of 1,1-bis[(pinacolato)boryl]alkanes for the transition-metal-frec borylation of aryl and vinyl halides: A combined experimental and theoretical investigation
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A new transition-metal-frec borylation of aryl and vinyl halides using l,l-bis[(pinacolato)boryl]alkanes as boron sources is described. In this transformation one of the boron groups from 1,1-bis[(pinacolato)boryl]alkanes is selectively transferred to aryl and vinyl halides in the presence of sodium tert-butoxide as the only activator to form organoboronate esters. Under the developed borylation conditions, a broad range of organohalides are borylated with excellent chemo-selectivity and functional group compatibility, thus offering a rare example of a transition-metal-frec borylation protocol. Experimental and theoretical studies have becn performed to elucidate the reaction mechanism, revealing the unusual formation of Lewis acid/base adduct betwecn organohalides and α-borylcarbanion, generated in situ from the reaction of l,l-bis[(pinacolato)boryl]alkanes with an alkoxide base, to facilitate the borylation reactions.
- Lee, Yeosan,Baek, Seung-Yeol,Park, Jinyoung,Kim, Seoung-Tae,Tussupbayev, Samat,Kim, Jeongho,Baik, Mu-Hyun,Cho, Seung Hwan
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p. 975 - 984
(2017/05/16)
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- SUBSTITUTED QUINOXALINE DERIVATIVES
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The present invention relates to substituted quinoxaline derivatives. These compounds are useful for the prevention and/or treatment of several medical conditions including hyperproliferative disorders and diseases.
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Page/Page column 133
(2016/11/28)
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- Iridium/N-heterocyclic carbene-catalyzed C-H borylation of arenes by diisopropylaminoborane
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Catalytic C-H borylation of arenes has been widely used in organic synthesis because it allows the introduction of a versatile boron functionality directly onto simple, unfunctionalized arenes. We report herein the use of diisopropylaminoborane as a boron source in C-H borylation of arenes. An iridium(I) complex with 1,3-dicyclohexylimidazol-2-ylidene is found to efficiently catalyze the borylation of arenes and heteroarenes. The resulting aminoborylated products can be converted to the corresponding boronic acid derivatives simply by treatment with suitable diols or diamines.
- Tobisu, Mamoru,Igarashi, Takuya,Chatani, Naoto
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supporting information
p. 654 - 661
(2016/07/06)
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- The drastic effect of cobalt and chromium catalysts in the borylation of arylzinc reagents
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A new synthetic approach to arylboronic esters from arylzinc reagents with boryl electrophiles MeOB(OR)2 has been developed. Furthermore, this protocol could be applied to the cyclization/borylation of alkynylaryl iodides to afford cyclized vinylboronic esters.
- Komeyama, Kimihiro,Kiguchi, Shinnosuke,Takaki, Ken
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supporting information
p. 7009 - 7012
(2016/06/09)
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- METHOD FOR PREPARING AMINOARYLBORANE COMPOUNDS OR DERIVATIVES THEREOF
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The present invention provides a process for the preparation of aminoarylborane compounds and derivatives thereof comprising a step of arylation by reacting an aryl chloride with an aminoborane compound in the presence of a catalytic system.
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Page/Page column 100
(2015/06/18)
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- Method for preparing aminoarylborane compounds or derivatives thereof
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The present invention provides a process for the preparation of aminoarylborane compounds and derivatives thereof comprising a step of arylation by reacting an aryl chloride with an aminoborane compound in the presence of a catalytic system. Typically, th
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Paragraph 0304
(2015/06/17)
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- Borylation of unactivated aryl chlorides under mild conditions by using diisopropylaminoborane as a borylating reagent
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The synthesis of arylboronic ester derivatives from aryl chlorides by using aryl(amino)boranes is described. Palladium-catalyzed coupling between aryl chlorides and diisopropylaminoborane leads to the formation of a C-B bond under mild conditions. A wide range of functional groups are tolerated, making this method particularly useful for the borylation of functionalized aromatics. Salts make the difference: The synthesis of arylboronic ester derivatives from aryl chlorides by using aryl(amino)boranes is described. Palladium-catalyzed coupling between aryl chlorides and diisopropylaminoborane leads to the formation of a C-B bond under mild conditions. A wide range of substituents, including electron-withdrawing groups, are tolerated (see scheme).
- Guerrand, Helene D. S.,Marciasini, Ludovic D.,Jousseaume, Melissa,Vaultier, Michel,Pucheault, Mathieu
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supporting information
p. 5573 - 5579
(2014/05/20)
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- Palladium-catalyzed allylic cross-coupling reactions of primary and secondary homoallylic electrophiles
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The Pd(0)-catalyzed allylic cross-coupling of homoallylic tosylate substrates using boronic acids and pinacol esters is reported. The reaction uses 2-(4,5-dihydro-2-oxazolyl)quinoline (quinox) as a ligand and is performed at ambient temperature. The scope of the reaction is broad in terms of both the boronate transmetalating reagent and the substrate and includes secondary tosylates. Mechanistic studies support an alkene-mediated SN2-type stereoinvertive oxidative addition of unactivated primary and secondary alkyl tosylates.
- Stokes, Benjamin J.,Opra, Susanne M.,Sigman, Matthew S.
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supporting information; experimental part
p. 11408 - 11411
(2012/09/05)
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- Anomalous reactivity of silylborane: Transition-metal-free boryl substitution of aryl, alkenyl, and alkyl halides with silylborane/alkoxy base systems
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An unexpected borylation of organic halides with a silyborane in the presence of an alkoxy base has been observed. This formal nucleophilic boryl substitution can be applied to a broad range of substrates with high functional group compatibility. Even sterically hindered aryl bromides afforded the corresponding boryl compounds in high yields. Preliminary mechanistic studies indicated that this boryl substitution is promoted by neither transition-metal contamination nor a radical-mediated process.
- Yamamoto, Eiji,Izumi, Kiyotaka,Horita, Yuko,Ito, Hajime
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supporting information
p. 19997 - 20000
(2013/02/23)
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- Convenient synthesis of 1H-indol-1-yl boronates via palladium(0)-catalyzed borylation of bromo-1H-indoles with 'pinacolborane'
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An atom-economic Pd0-catalyzed synthesis of a series of pinacol-type indolylboronates 3 from the corresponding bromoindole substrates 2 and pinacolborane (pinBH) as borylating agent was elaborated. The optimal catalyst system consisted of a 1:2 mixture of [Pd(OAc)2] and the ortho-substituted biphenylphosphine ligand L-3 (Scheme 4, Table). Our synthetic protocol was applied to the fast, preparative-scale synthesis of 1-substituted indolylboronates 3a-h in the presence of different functional groups, and at a catalyst load of only 1 mol-% of Pd.
- Stadlwieser, Josef F.,Dambaur, Markus E.
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p. 936 - 946
(2007/10/03)
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- Thienopyridine and furopyridine kinase inhibitors
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Compounds having the formula are useful for inhibiting protein tyrosine kinases. The present invention also discloses methods of making the compounds, compositions containing the compounds, and methods of treatment using the compounds.
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