- Three-Component Couplings among Heteroarenes, Difluorocyclopropenes, and Water via C-H Activation
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Three-component couplings have been realized for efficiently constructing various nitrogen-containing skeletons via C-H activation, where difluorocyclopropenes have been first identified as coupling partners. Many substrates including sp2 and sp3 C-H substrates were well tolerated, furnishing the corresponding products in good yields. Furthermore, a catalyst-dependent reaction was also developed, enabling divergent construction of two different frameworks. The application value of these reactions was demonstrated in gram-scale experiments with as little as 1 mol % catalyst.
- Liu, Xuexin,Chen, Jian,Yang, Chunyan,Wu, Zhouping,Li, Zhiyang,Shi, Yuesen,Huang, Tianle,Yang, Zhongzhen,Wu, Yong
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supporting information
p. 6831 - 6835
(2021/09/08)
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- Photoarylation of Pyridines Using Aryldiazonium Salts and Visible Light: An EDA Approach
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A metal-free methodology for the photoarylation of pyridines, in water, is described giving 2 and 4-arylated-pyridines in yields up to 96percent. The scope of the aryldiazonium salts is presented showing important results depending on the nature and position of the substituent group in the diazonium salt, that is, electron-donating or electron-withdrawing in the ortho, meta, or para positions. Further heteroaromatics were also successfully photoarylated. Mechanistic studies and comparison between our methodology and similar metal-catalyzed procedures are presented, suggesting the occurrence of a visible-light EDA complex which generates the aryl radical with no need for an additional photocatalyst.
- Bartolomeu, Aloisio De A.,Brocksom, Timothy J.,De Oliveira, Kleber T.,No?l, Timothy,Silva, Rodrigo C.
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- Synthesis, structure, and synthetic potential of arenediazonium trifluoromethanesulfonates as stable and safe diazonium salts
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Aromatic diazonium salts are valuable building blocks for organic synthesis; however, in most cases, they are unstable, unsafe, poorly soluble, and/or expensive. In this paper, we have shown that a variety of stable and safe arenediazonium triflates ArN2+ TfO– can be obtained easily and in high yields by diazotization of anilines with tert-butyl nitrite in the presence of trifluoromethanesulfonic acid. Arenediazonium triflates are relatively shelf-stable in the dry state. They dissolve well in water, as well as polar and even nonpolar organic solvents. Less than 800 J/g of energy is released during the thermal decomposition of these salts, which indicates their explosion safety. Arenediazonium triflates have a high reactivity in the known reactions of diazonium chemistry, and undergo an unusual metal-free chlorodediazonization reaction with chloroform and CCl4.
- Filimonov, Victor D.,Krasnokutskaya, Elena A.,Kassanova, Assia Zh.,Fedorova, Valentina A.,Stankevich, Ksenia S.,Naumov, Nikolay G.,Bondarev, Alexander A.,Kataeva, Veronika A.
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supporting information
p. 665 - 674
(2018/09/14)
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- Synthesis of Bi(hetero)aryls via Sequential Oxidation and Decarboxylation of Benzylamines in a Batch/Fully Automated Continuous Flow Process
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Catalytic dehydrogenative cross-coupling of two C–H bonds represents a green strategy in view of the atom- and step-economy. However, the challenge is to discover a new innovative bond strategy, especially for the direct coupling between Csp2–H
- Mahajan, Bhushan,Aand, Dnyaneshwar,Singh, Ajay K.
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supporting information
p. 2831 - 2835
(2018/06/21)
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- An Iron-Based Long-Lived Catalyst for Direct C?H Arylation of Arenes and Heteroarenes
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Direct C?H arylation of arenes and heteroarenes to biaryls at ambient temperature has been accomplished using a phenalenyl-supported iron(III) catalyst. The present catalyst requires a chemical reductant such as potassium and functions without any light stimulation. C?H arylation of various heteroarenes including pyridine as well as unactivated arene such as benzene delivered good to excellent yield (28 examples, up to 92 %) at room temperature. A combined effort based on experiments and theoretical calculations established that a phenalenyl-based radical species (generated by chemical reduction of the iron(III) coordinated phenalenyl complex) plays key role during the catalysis. Furthermore, this catalyst displayed remarkable stability during the catalysis, as evident from the fact that it was still usable over ten consecutive catalytic runs without losing its catalytic efficiency.
- Chakraborty, Soumi,Ahmed, Jasimuddin,Shaw, Bikash Kumar,Jose, Anex,Mandal, Swadhin K.
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p. 17651 - 17655
(2018/11/10)
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- A tetranuclear CuII2DyIII2 coordination cluster as a Suzuki (C-C) coupling reaction promoter
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The air-stable tetranuclear coordination cluster [CuII2DyIII2L4(NO3)2(CH3CN)2]·2(CH3CN), which can be obtained in high yield, promotes the Suzuki coupling reaction of phenylboronic acid with substituted aryl halides under environmentally benign conditions.
- Kumar, Prashant,Griffiths, Kieran,Anson, Christopher E.,Powell, Annie K.,Kostakis, George E.
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supporting information
p. 17202 - 17205
(2019/01/03)
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- C6-Selective Direct Arylation of 2-Phenylpyridine via an Activated N-methylpyridinium Salt: A Combined Experimental and Theoretical Study
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An elegant pre-activation strategy, based on the formation of N-methylpyridinium iodide salts for C6-selective direct arylation of 2-phenylpyridines using Pd/Cu cooperative catalysis, has been developed. By this methodology, a wide range of unsymmetrical 2, 6-diarylpyridines were synthesized with high reactivity and regioselectivity as well as good functional group tolerance. In particular, challenging substrates bearing electron donating groups (EDGs), such as OMe, NMe2, were also successfully employed in this reaction. Deuterium incorporation studies revealed that the C?H bond acidity is improved significantly in N-methylpyridinium salts compared with their N-Oxide and N-iminopyridinium ylide counterparts, thus solving the long-standing problem associated with previous strategies for the synthesis of diaryl pyridines. Finally, the control experiments and DFT calculations supported a Pd-catalyzed and Cu-mediated mechanism in which a carbenoid copper species that is formed in-situ from N-methylpyridinium salts, participates in a Pd-catalyzed arylation followed by an iodide-promoted N-demethylation process. (Figure presented.).
- Yin, Changzhen,Zhong, Kangbao,Li, Wenjing,Yang, Xiao,Sun, Rui,Zhang, Chunchun,Zheng, Xueli,Yuan, Maolin,Li, Ruixiang,Lan, Yu,Fu, Haiyan,Chen, Hua
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supporting information
p. 3990 - 3998
(2018/09/12)
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- Visible-Light-Promoted Arylation Reactions Photocatalyzed by Bismuth(III) Oxide
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Bismuth(III) oxide has been successfully applied as a photocatalyst in the arylation of heteroarenes with diazonium salts. With a low catalyst loading (1 to 5 mol-%), this cheap and nontoxic semiconductor could efficiently promote the formation of the aryl radical under visible light irradiation. The arylated products are obtained in moderate to good yields, and the process admits straightforward scale-up (10 mmol; 1 mol-% Bi2O3). In two cases, the diazonium salt was generated in situ and used in the photocatalytic arylation in a tandem manner. Besides heteroarenes, Bi2O3 also catalyzed the arylation of differently substituted alkenes and alkynes, thus representing a viable and practical alternative to the more commonly used ruthenium complexes and organic dyes.
- Buglioni, Laura,Riente, Paola,Palomares, Emilio,Pericàs, Miquel A.
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supporting information
p. 6986 - 6990
(2017/12/26)
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- Blue light mediated C-H arylation of heteroarenes using TiO2 as an immobilized photocatalyst in a continuous-flow microreactor
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Titanium dioxide was applied as an immobilized photocatalyst in a microstructured falling film reactor for the continuous-flow C-H arylation of heteroarenes with aryldiazonium salts as the starting material. Detailed investigations of the catalyst and a successful long-term run proved its excellent usability for this process. Very good yields up to 99% were achieved with broad substrate scope and were compared with batch synthesis. The transfer to the continuous-flow mode revealed an impressive boost in reactor performance solely resulting from the improved irradiation and contact of the catalyst, substrate and light.
- Fabry, David C.,Ho, Yee Ann,Zapf, Ralf,Tremel, Wolfgang,Panth?fer, Martin,Rueping, Magnus,Rehm, Thomas H.
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supporting information
p. 1911 - 1918
(2017/06/09)
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- A new face of phenalenyl-based radicals in the transition metal-free C-H arylation of heteroarenes at room temperature: Trapping the radical initiator: Via C-C σ-bond formation
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The radical-mediated transition metal-free approach for the direct C-H bond functionalization of arenes is considered as a cost effective alternative to transition metal-based catalysis. An organic ligand-based radical plays a key role by generating an aryl radical which undergoes a subsequent functionalization process. The design principle of the present study takes advantage of a relatively stable odd alternant hydrocarbon-based phenalenyl (PLY) radical. In this study, the first transition metal-free catalyzed direct C-H arylation of a variety of heteroarenes such as azoles, furan, thiophene and pyridine at room temperature has been reported using a phenalenyl-based radical without employing any photoactivation step. This protocol has been successfully applied to the gram scale synthesis of core moieties of bioactive molecules. The phenalenyl-based radical initiator has been characterized crystallographically by trapping it via the formation of a C-C σ-bond between the phenalenyl radical and solvent-based radical species.
- Ahmed, Jasimuddin,Sreejyothi,Vijaykumar, Gonela,Jose, Anex,Raj, Manthan,Mandal, Swadhin K.
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p. 7798 - 7806
(2017/10/30)
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- Synthesis of 2-phenyl pyridine derivatives from aryl ketones and 1,3-diaminopropane using palladium acetate as a catalyst
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A simple and efficient method for the synthesis of 2-phenyl pyridine via cyclization of aryl ketone with 1,3-diaminopropane using palladium acetate is established. This method is mild, operationally simple, involves short reaction time and involves easy workup procedure to afford the corresponding 2-phenyl pyridines in moderate to good yield.
- Ghodse, Shrikant M.,Telvekar, Vikas N.
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supporting information
p. 524 - 526
(2017/01/17)
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- A 2-substituted pyridine-based pharmaceutical intermediates the synthetic method of the compound of
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The invention relates to a synthesis method of a 2-substituted pyridine-class drug intermediate compound shown in the formula (I) (please see the formula in the specification). The method includes the steps that when catalysts, ligand, alkali and additives exist, a compound with the formula (II) and a compound with the formula (III) react in an organic solvent so that the compound shown in the formula (I) (please see the formula in the specification) can be obtained, wherein R1, R2 and R3 are independently selected from H, halogen or C-C6 alkyl groups; the formula (please see the formula in the specification) is a C6-C10 aryl group which is not substituted or has 1-2 substitutent groups or is a C4-C10 heterocyclic radical which is not substituted or has 1-2 substitutent groups, and the substitutent grous are halogen, nitro or C1-C6 alkyl groups; Hal serves as the halogen. According to the method, the catalysts, the ligand, the alkali and the additives are properly selected and combined, and therefore a high yield is achieved, and the method has good industrial prospects and good application potentiality.
- -
-
Paragraph 0052; 0053; 0054; 0055; 0056; 0057
(2016/12/22)
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- Meta-Selective CAr-H Nitration of Arenes through a Ru3(CO)12-Catalyzed Ortho-Metalation Strategy
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The first example of transition metal-catalyzed meta-selective CAr-H nitration of arenes is described. With the use of Ru3(CO)12 as the catalyst and Cu(NO3)2·3H2O as the nitro source, a wide spectrum of arenes bearing diversified N-heterocycles or oximido as the directing groups were nitrated with meta-selectivity exclusively. Mechanism studies have demonstrated the formation of a new 18e-octahedral ruthenium species as a key ortho-CAr-H metalated intermediate, which may be responsible for the subsequent meta-selective electrophilic aromatic substitution (SEAr). Moreover, this approach provides a fast-track strategy for atom/step economical synthesis of many useful pharmaceutical molecules.
- Fan, Zhoulong,Ni, Jiabin,Zhang, Ao
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supporting information
p. 8470 - 8475
(2016/07/26)
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- Multicomponent self-assembly of a pentanuclear Ir-Zn heterometal-organic polyhedron for carbon dioxide fixation and sulfite sequestration
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By incorporating a fac-tris(4-(2-pyridinyl)phenylamine)iridium as the backbone of the tripodal ligand to constrain the coordination geometry of Zn(ii) ions, a pentanuclear Ir-Zn heterometal-organic luminescent polyhedron was obtained via a subcomponent self-assembly for carbon dioxide fixation and sulfite sequestration.
- Li, Xuezhao,Wu, Jinguo,He, Cheng,Zhang, Rong,Duan, Chunying
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p. 5104 - 5107
(2016/04/26)
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- Chelation-Assisted Copper-Mediated Direct Acetylamination of 2-Arylpyridine C-H Bonds with Cyanate Salts
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In this study, the coupling of 2-phenylpyridine derivatives and potassium cyanate through C-H bond functionalization in the presence of a copper salt is developed for the first time. By this protocol, various heteroarylated acetanilide derivatives are synthesized in good yields. 2-Phenylpyridines containing electron-donating and -withdrawing groups appear to be well-tolerated by this transformation.
- Kianmehr, Ebrahim,Amiri Lomedasht, Yousef,Faghih, Nasser,Khan, Khalid Mohammed
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p. 6087 - 6092
(2016/07/23)
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- Engineering an iridium-containing metal-organic molecular capsule for induced-fit geometrical conversion and dual catalysis
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By introducing photoactive fac-tris(2-phenylpyridine)iridium moieties as a ligand backbone to constrain the coordination geometry of cobalt ions, a multifunctional Ir2Co3-type capsule was achieved and showed induced-fit capsule-capsule conversion by cooperative binding one carbonate anion with the equatorial Co(ii) centers. The capsule combined photocatalysis and transition metal activation synergistically and exhibited efficient catalytic ability on visible light-activated α-trichloromethylation.
- Li, Xuezhao,Wu, Jinguo,Chen, Liyong,Zhong, Xiaoming,He, Cheng,Zhang, Rong,Duan, Chunying
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supporting information
p. 9628 - 9631
(2016/08/04)
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- NOVEL NAPHTHOTRIAZOLE DERIVATIVE AND ORGANIC ELECTROLUMINESCENCE ELEMENT
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Naphthotriazole derivatives represented by the following general formula (1), wherein, Ar 1 is an aromatic hydrocarbon group or an aromatic heterocyclic group, and A is a group that contains an aromatic heterocyclic group. The compound features excellent electron injection/transporting capability, a high hole-blocking power and a high stability in the form of a thin film, and can be used as a material for producing highly efficient and highly durable organic electroluminescent devices.
- -
-
Paragraph 0559-0564
(2016/11/17)
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- Unexpected dual role of titanium dioxide in the visible light heterogeneous catalyzed C-H arylation of heteroarenes
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The direct arylation of heteroaromatics with an easily accessible and recyclable, heterogeneous TiO2 catalyst and visible light was developed. Electron-rich as well as electron-poor heteroarenes could be applied in this transformation, and the corresponding products were isolated in very good yields. Azoethers were detected as reactive intermediates, and the unexpected role of TiO2 in their formation as well as reaction was established.
- Zoller, Jochen,Fabry, David C.,Rueping, Magnus
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p. 3900 - 3904
(2015/06/16)
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- Structure-activity relationship studies of SEN12333 analogues: Determination of the optimal requirements for binding affinities at α7 nAChRs through incorporation of known structural motifs
-
Alpha7 nicotinic acetylcholine receptors (nAChRs) have implications in the regulation of cognitive processes such as memory and attention and have been identified as a promising therapeutic target for the treatment of the cognitive deficits associated with schizophrenia and Alzheimer's disease (AD). Structure affinity relationship studies of the previously described α7 agonist SEN12333 (8), have resulted in the identification of compound 45, a potent and selective agonist of the α7 nAChR with enhanced affinity and improved physicochemical properties over the parent compound (SEN12333, 8).
- Beinat, Corinne,Reekie, Tristan,Banister, Samuel D.,O'Brien-Brown, James,Xie, Teresa,Olson, Thao T.,Xiao, Yingxian,Harvey, Andrew,O'Connor, Susan,Coles, Carolyn,Grishin, Anton,Kolesik, Peter,Tsanaktsidis, John,Kassiou, Michael
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supporting information
p. 277 - 301
(2015/03/31)
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- Contrasting Anticancer Activity of Half-Sandwich Iridium(III) Complexes Bearing Functionally Diverse 2-Phenylpyridine Ligands
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We report the synthesis, characterization, and antiproliferative activity of 15 iridium(III) half-sandwich complexes of the type [(η5-Cp?)Ir(2-(R′-phenyl)-R-pyridine)Cl] bearing either an electron-donating (-OH, -CH2OH, -CH3) or electron-withdrawing (-F, -CHO, -NO2) group at various positions on the 2-phenylpyridine (2-PhPy) chelating ligand giving rise to six sets of structural isomers. The X-ray crystal structures of [(η5-Cp?)Ir(2-(2′-fluorophenyl)pyridine)Cl] (1) and [(η5-Cp?)Ir(2-(4′-fluorophenyl)pyridine)Cl] (2) exhibit the expected "piano-stool" configuration. DFT calculations showed that substituents caused only localized effects on the electrostatic potential surface of the chelating 2-PhPy ligand of the complexes. Hydrolysis of all complexes is rapid, but readily reversed by addition of NaCl. The complexes show preferential binding to 9-ethylguanine over 9-methyladenine and are active catalysts for the oxidation of NADH to NAD+. Antiproliferative activity experiments in A2780 ovarian, MCF-7 breast, A549 lung, and HCT116 colon cancer cell lines showed IC50 values ranging from 1 to 89 μM, with the most potent complex, [(η5-Cp?)Ir(2-(2′-methylphenyl)pyridine)Cl] (13) (A2780 IC50 = 1.18 μM), being 10× more active than the parent, [(η5-Cp?)Ir(2-phenylpyridine)Cl], and 2× more active than [(η5-CpxPh)Ir(2-phenylpyridine)Cl]. Intriguingly, contrasting biological activities are observed between structural isomers despite exhibiting similar chemical reactivity. For pairs of structural isomers both the nature and position of the functional group can affect the hydrophobicity of the complex. An increase in hydrophobicity resulted in enhanced cellular-iridium accumulation in A2780 ovarian cells, which generally gave rise to an increase in potency. The structural isomers [(η5-Cp?)Ir(2-(4′-fluorophenyl)pyridine)Cl] (2) and [(η5-Cp?)Ir(2-phenyl-5-fluoropyridine)Cl] (4) preferentially localized in the cytosol > membrane and particulate > nucleus > cytoskeleton. This work highlights the strong dependence of biological behavior on the nature and position of the substituent on the chelating ligand and shows how this class of organometallic anticancer complexes can be fine-tuned to increase their potency without using extended cyclopentadienyl systems. (Chemical Equation Presented).
- Millett, Adam J.,Habtemariam, Abraha,Romero-Canelón, Isolda,Clarkson, Guy J.,Sadler, Peter J.
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supporting information
p. 2683 - 2694
(2015/06/23)
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- Catalytic meta-selective C-H functionalization to construct quaternary carbon centres
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A catalytic meta-selective C-H functionalization of 2-phenylpyridines using a range of tertiary halides is described. The protocol is simple to perform and uses commercially available reagents to construct challenging quaternary carbon centres in a regioselective manner. Preliminary studies suggest the C-H functionalization proceeds through a radical process directed via a remote σ-activation.
- Paterson, Andrew J.,St John-Campbell, Sahra,Mahon, Mary F.,Press, Neil J.,Frost, Christopher G.
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supporting information
p. 12807 - 12810
(2015/08/06)
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- Copper acetate-DMSO promoted methylthiolation of arenes and heteroarenes
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An unprecedented copper acetate-DMSO promoted methylthiolation of arenes and heteroarenes in the presence of air has been developed. The reaction is highly regioselective under the directing group influence of pyridine and pyrimidine functional units and gives the thiomethylated product in moderate to high yields.
- Sharma, Poonam,Rohilla, Sandeep,Jain, Nidhi
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p. 4116 - 4122
(2015/05/05)
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- Copper-catalyzed aerobic synthesis of 2-arylpyridines from acetophenones and 1,3-diaminopropane
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A copper-catalyzed reaction providing direct access to 2-arylpyridines from acetophenones and 1,3-diaminopropane is described. A range of electronically diverse acetophenones undergo this transformation, affording 2-arylpyridines in good yields. (Chemical Equation Presented).
- Xi, Long-Yi,Zhang, Ruo-Yi,Liang, Shuai,Chen, Shan-Yong,Yu, Xiao-Qi
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supporting information
p. 5269 - 5271
(2015/01/09)
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- Silyl-protected dioxaborinanes: Application in the Suzuki cross-coupling reaction
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The synthesis of a range of novel silyl-protected dioxaborinanes as a column- and bench-stable boron reagent were found to be advantageous to achieving good yields in palladium-catalysed cross-coupling reactions under standard conditions. This journal is The Royal Society of Chemistry.
- Goggins, Sean,Rosevere, Eleanor,Bellini, Clement,Allen, Joseph C.,Marsh, Barrie J.,Mahon, Mary F.,Frost, Christopher G.
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supporting information
p. 47 - 52
(2014/01/06)
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- FAK AND FLT3 INHIBITORS
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The use of a compound of the formula (I): (Formula (I)) in the preparation of a medicament for treating Acute Myeloid Leukemia or a disease ameliorated by the inhibition of Flt3, or Flt3 and FAK.
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Page/Page column 78
(2014/03/22)
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- Arylation of 2-substituted pyridines via Pd-catalyzed decarboxylative cross-coupling reactions of 2-picolinic acid
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The novel palladium-catalyzed decarboxylative cross-coupling reactions of 2-picolinic acid with aryl and heteroaryl bromides including benzenes, naphthalenes, pyridines and quinolines for C-C bond formation have been successfully achieved. This journal is
- Li, Xinjian,Zou, Dapeng,Leng, Faqiang,Sun, Chunxia,Li, Jingya,Wu, Yangjie,Wu, Yusheng
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supporting information
p. 312 - 314
(2013/02/22)
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- Tetrabutylammonium 2-pyridyltriolborate salts for Suzuki-Miyaura cross-coupling reactions with aryl chlorides
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Palladium-catalyzed Suzuki-Miyaura cross-coupling reactions of tetrabutylammonium 2-pyridyltriolborate salts with various aryl (heteroaryl) chlorides can produce the corresponding desired coupling products with good to excellent yields. These tetrabutylammonium salts are more reactive than the corresponding lithium salts. The coupling reactions with aryl chlorides progressed in the presence of PdCl2dcpp (3 mol %) and CuI/MeNHCH 2CH2OH (20 mol %) in anhydrous DMF without bases.
- Sakashita, Shohei,Takizawa, Miho,Sugai, Juugaku,Ito, Hajime,Yamamoto, Yasunori
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supporting information
p. 4308 - 4311
(2013/09/24)
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- Development of a palladium-catalyzed decarboxylative cross-coupling of (2-azaaryl)carboxylates with aryl halides Dedicated to Professor Melanie Sanford on receipt of the Tetrahedron Young Investigator Award
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A catalytic method for the decarboxylative coupling of 2-(azaaryl) carboxylates with aryl halides is described. The decarboxylative cross-coupling presented is mediated by a system catalytic in both palladium and copper without requiring stoichiometric amounts of organometallic reagents or organoboronic acids. This method circumvents additional synthetic steps required to prepare 2-azaaryl organometallics and organoborates as nucleophilic coupling partners, which are prone to protodemetallation and protodeborylation and produce potentially toxic byproducts.
- Haley, Christopher K.,Gilmore, Christopher D.,Stoltz, Brian M.
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p. 5732 - 5736
(2013/07/11)
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- FAK INHIBITORS
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A compound of the formula (I): where R1 or R2 is a cycle amine group and R5 is an aromatic group with a carbonyl containing substituent for use as a FAK inhibitor.
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Page/Page column 76; 77
(2012/09/10)
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- CYCLOMETALATED TRANSITION METAL DYES
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The present invention provides substituted cyclometalated dyes with wider absorbance bands in the visible spectrum. The compounds have hexacoordinate structures as shown in formula (I) where the central transition metal (M) is bonded to two substituted bi
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Page/Page column 60-61
(2012/12/13)
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- Copper-mediated chelation-assisted ortho nitration of (hetero)arenes
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A novel copper-mediated chelation-assisted ortho C-H nitration of (hetero)arenes has been developed for the first time, which used dioxygen as terminal oxidant and 1, 2, 3-TCP as solvent, leading to the synthesis of nitroaromatics with excellent regiosele
- Zhang, Lin,Liu, Zhenhua,Li, Huiqin,Fang, Guichun,Barry, Badru-Deen,Belay, Tuemay Abadi,Bi, Xihe,Liu, Qun
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supporting information; experimental part
p. 6536 - 6539
(2012/02/04)
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- Negishi coupling of 2-pyridylzinc bromide-paradigm shift in cross-coupling chemistry?
-
The efficient cross-coupling of 2-pyridylzinc bromide with functionalized aryl halides has been accomplished by a simple and highly efficient protocol. To the best of our knowledge, we report the first shelf life study of 2-pyridylzinc bromide which confirms the excellent stability of this compound and underlines the synthetic value of organozinc reagents in the cross-coupling reactions of sensitive heterocyclic nucleophiles on academic and commercial scale.
- Coleridge, Brian M.,Bello, Charles S.,Ellenberger, David H.,Leitner, Andreas
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experimental part
p. 357 - 359
(2010/03/24)
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- A mild negishi cross-coupling of 2-heterocyclic organozinc reagents and aryl chlorides
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A mild Negishi cross-coupling of 2-heterocyclic organozinc reagents and aryl chlorides is described. The use of Pd2(dba)3 and X-Phos as a ligand provides high yields for many examples. An efficient method to generate the organozinc reagents at room temperature is also demonstrated.
- Luzung, Michael R.,Patel, Jigar S.,Yin, Jingjun
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supporting information; experimental part
p. 8330 - 8332
(2011/03/17)
-
- Cyclometalated ru complexes of type [RuII(N^N) 2(C^N)]z: Physicochemical response to substituents installed on the anionic ligand
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The electrochemical and photophysical properties of a series ofRu(II) complexes related to [Ru(dcbpyH2)2(ppy)]1+ (1; dcbpy-H2 = 4,4′-dicarboxy-2,2′-bipyridine; ppy = 2-phenylpyridine) were examined to elucidate
- Bomben, Paolo G.,Koivisto, Bryan D.,Berlinguette, Curtis P.
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experimental part
p. 4960 - 4971
(2010/07/08)
-
- REAGENT FOR ORGANIC SYNTHESIS REACTION CONTAINING ORGANIC TRIOL BORATE SALT
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[Problem] To provide an organoboron compound-containing reagent for organic synthesis reactions which undergoes no trimerization with dehydration, does not necessitate activation with a base, and is stable and highly active. [Means for Solving Problems] The reagent for organic synthesis reactions contains an organic triol borate salt represented by any of the general formulae (I) to (III) and general formula (XVI): (wherein R1 represents alkyl, alkenyl, etc.; R2 represents optionally substituted alkyl, alkenyl, alkynyl, etc. or represents hydrogen; m+ represents an alkaline metal ion, phosphonium ion, or given ammonium ion; M2+ represents an alkaline earth metal; X represents halogen or alkoxide; Y represents an alkali metal ion, etc.; A represents optionally substituted methylene; and n represents an integer).
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Page/Page column 18
(2010/04/30)
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- Palladium-catalyzed cross-coupling reaction of heteroaryltriolborates with aryl halides for synthesis of biaryls
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Cyclic triolborates possessing a heteroaromatic ring on the boron atom [ArB(OCH2)3CHCH3]M (M=K, Na, Li) were prepared in high yields from heteroarylboronic acids, 1,1,1-tris(hydroxymethyl)ethane (triol) and KOH or NaH. The corresponding lithium salts were synthesized from aryllithiums, B(OMe)3 and triol. They were air-stable white solids that were convenient for handling in air. High performance of these triolborates for metal-catalyzed bond-forming reactions was demonstrated in palladium-catalyzed cross-coupling reactions with haloarenes. Although the use of heteroarylboronic acids often results in very low yields due to competitive hydrolytic B-C bond cleavage with water under typical conditions using aqueous bases, triolborates possessing a 2-pyridyl, 3-pyridyl or 2-thiophenyl ring afforded biaryls in high yields at 50-120C in anhydrous DMF. There was a strong accelerating effect of CuI for reactions of 2-and 3-pyridylborate derivatives, whereas 2-thiophenyl derivatives reacted smoothly resulting in high yields in the absence of CuI.
- Yamamoto, Yasunori,Takizawa, Miho,Yu, Xiao-Qiang,Miyaura, Norio
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experimental part
p. 359 - 368
(2010/04/27)
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- Direct ortho-arylation of N-phenacylpyridinium bromide by palladium-catalyzed C-H-bond activation
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A novel palladium catalyzed direct ortho-arylation of N-phenacylpyridinium bromide was developed. The amazing N-phenacyl group regioselectively activates the C-H bond of pyridine and automatically departs from the arylated products. A kinetic isotope effe
- Xu, Jimin,Cheng, Guolin,Su, Deyong,Liu, Yantao,Wang, Xinyan,Hu, Yuefei
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supporting information; experimental part
p. 13105 - 13110
(2010/06/16)
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- Palladium-catalysed cross-coupling of 2-trimethylsilylpyridine with aryl halides
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Palladium-catalysed cross-coupling of 2-trimethylsilylpyridine with aryl halides in the presence of stoichiometric silver(I) oxide, and catalytic TBAF allows the rapid preparation of the corresponding pyridin-2-ylaryl compounds in moderate to good yields
- Napier, Spencer,Marcuccio, Sebastian M.,Tye, Heather,Whittaker, Mark
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body text
p. 6314 - 6315
(2009/04/06)
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- Cyclic triolborates: Air- and water-stable ate complexes of organoboronic acids
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(Chemical Equation Presented) A borate in the hand is a convenient reagent for palladium- and copper-catalyzed C-C and C-N bond-forming reactions, especially when, like the title bench-stable complexes, it demonstrates high transmetalation efficiency. Cyclic triolborates can be synthesized readily from organoboronic acids (see scheme), can be handled and stored without special precautions, and are relatively soluble in organic solvents.
- Yamamoto, Yasunori,Takizawa, Miho,Yu, Xiao-Qiang,Miyaura, Norio
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p. 928 - 931
(2008/09/20)
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- CAPREOMYCIN DERIVATIVES AND THEIR USE AS ANTIBACTERIALS
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The present invention relates to phenylurea derivatives of capreomycin I, IIB, IIA, or IB, and metabolites and pharmaceutically acceptable salts and solvates thereof. The compounds of the present invention are useful as antibacterial agents for treating b
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Page/Page column 63
(2008/06/13)
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- Capreomycin derivatives and their use as antibacterials
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The present subject matter relates to phenylurea capreomycin derivatives, and to metabolites and pharmaceutically acceptable salts and solvates thereof. The compounds of the present subject matter are useful as antibacterial agents for treating bacterial
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Page/Page column 22
(2008/06/13)
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- The preparation of a stable 2-pyridylboronate and its reactivity in the Suzuki-Miyaura cross-coupling reaction
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The preparation and reactivity of a 2-pyridylboronate stabilised by N-phenyldiethanolamine is described. In Suzuki-Miyaura cross-coupling reactions employing this boronate, significant aryl-aryl exchange from the phosphine ligand was observed with some combinations of ligand and substrates. The amount of the exchange by-product can be minimised by appropriate choice of phosphine ligand.
- Hodgson, Paul B.,Salingue, Fabrice H.
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p. 685 - 687
(2007/10/03)
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- Orally active CCR5 antagonists as anti-HIV-1 agents 2: Synthesis and biological activities of anilide derivatives containing a pyridine N-oxide moiety
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In order to develop orally active CCR5 antagonists, we investigated 1-benzoxepine derivatives containing new polar substituents, such as phosphonate, phosphine oxide or pyridine N-oxide moieties, as replacements for the previoiusly reported quaternary ammonium moiety. Among these compounds, the 2-(α-hydroxybenzyl)pyridine N-oxide 5e exhibited moderate CCR5 antagonistic activity and had an acceptable pharmacokinetic profile in rats. Subsequent chemical modification was performed and compound (S)-5f possessing the (S)-configuration hydroxy group was found to be more active than the (R)-isomer. Replacement of the 1-benzoxepine ring with a 4-methylphenyl group by a 1-benzazepine ring with a 4-[2-(butoxy)ethoxy]phenyl group enhanced the activity in the binding assay. In addition, introduction of a 3-trifluoromethyl group on the phenyl group of the anilide moiety led to greatly increased activity in the HIV-1 envelope-mediated membrane fusion assay. In particular, compound (S)-5s showed the most potent CCR5 antagonistic activity (IC 50=7.2 nM) and inhibitory effect (IC50=5.4 nM) in the fusion assay, together with good pharmacokinetic properties in rats.
- Seto, Masaki,Aramaki, Yoshio,Imoto, Hiroshi,Aikawa, Katsuji,Oda, Tsuneo,Kanzaki, Naoyuki,Iizawa, Yuji,Baba, Masanori,Shiraishi, Mitsuru
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p. 818 - 829
(2007/10/03)
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- Microwave-assisted Negishi and Kumada cross-coupling reactions of aryl chlorides
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Rapid Pd or Ni-catalyzed microwave-accelerated Negishi and Kumada cross-coupling reactions of aryl chlorides in solution and on solid phase are reported.
- Walla, Peter,Kappe, C. Oliver
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p. 564 - 565
(2007/10/03)
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- New polystyrene-supported stable source of 2-pyridylboron reagent for Suzuki couplings in combinatorial chemistry
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The first stable polystyrene-supported 2-pyridylboron reagent has been prepared and involved in Suzuki-Miyaura couplings. Very efficient reactions have been obtained with clean release of target coupling products providing a new tool for combinatorial chemistry.
- Gros, Philippe,Doudouh, Abdelatif,Fort, Yves
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p. 6239 - 6241
(2007/10/03)
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- Preparation and reactions of new zincated nitrogen-containing heterocycles
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A range of nitrogen-containing iodinated or in some cases brominated heterocycles were converted to the corresponding zincated heterocyclic derivatives by the direct insertion of zinc dust under mild conditions (25°C to 70°C, 1-3 h) in a solvent like THF or DMAC. This reaction was extended to the preparation of zincated nucleic acid bases and nucleosides. The reaction of these new zinc reagents toward various electrophiles with palladium (O) or copper(I) catalysis allows the preparation of a broad range of polyfunctional nitrogen-containing heterocycles.
- Prasad, A. S. Bhanu,Stevenson, Thomas M.,Citineni, Janakiram Rao,Nyzam, Valerie,Knochel, Paul
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p. 7237 - 7254
(2007/10/03)
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- Selectivity in palladium(0)-catalyzed cross-coupling reactions: Application to a tandem Stille reaction
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A tandem palladium-catalyzed cross-coupling reaction between a pyridyl triflate 1a and a variety of aryl bromides mediated by hexamethylditin is described. The reaction apparently proceeds via the intermediacy of the labile pyridylstannane 1b indicating that the oxidative addition of palladium(0) to the triflate, subsequent transmetalation with hexamethylditin and reductive elimination occurs selectively in the presence of the aryl halide.
- Hitchcock,Mayhugh,Gregory
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p. 9085 - 9088
(2007/10/02)
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- N-Arylation of Pyridine with Diazonium Salts
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N-Arylation of pyridine with arenediazonium salts have been accomplished. 2,7-Dioxo-2,3-dihydro-7H-dibenzisoquinoline-1- and 2-methyl-6-oxo-2,6-dihydronaphthindole-1-diazonium salts have been converted into respectively N-substituted pyridines in quantitative yields.With 2,4-dinitrobenzenediazonium salts as an example, the reaction was shown to be of general character.Strong electron-acceptor properties of the arene residue in the diazo cation are necessary for the reaction to occur, since 4-nitrobenzenediazonium salts react to only a minor extent and benzenediazonium salts give no N-arylation products at all.
- Kazankov, M. V.,Makshanova, N. P.,Sadovykh, E. G.
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p. 414 - 417
(2007/10/03)
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