- Cp2Ni-KOt-Bu-BEt3 (or PPh3) catalyst system for direct C - H arylation of benzene, naphthalene, and pyridine
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Ni-catalyzed direct C - H arylation of benzene and naphthalene using aryl halides was investigated. For the first time, the arylation was successfully catalyzed by Cp2Ni (5 mol %) in the presence of KOt-Bu and BEt 3. This Ni catalyst system was also applied to direct C - H arylation of pyridine, an electron-deficient heteroarene; PPh3 was used instead of BEt3 in this case.
- Kobayashi, Osamu,Uraguchi, Daisuke,Yamakawa, Tetsu
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Read Online
- COMPOUNDS FOR THE MODULATION OF PROPROTEIN CONVERTASE SUBTILISIN/KEXIN TYPE 9 (PCSK9)
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The present disclosure relates to novel compounds capable of binding to PCSK9, thereby modulating PCSK9 biological activity. Also provided are compositions comprising these compounds, methods of preparing the compounds, and methods for use of the compounds in the treatment of PCSK9-related conditions and diseases.
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Paragraph 00232
(2020/12/30)
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- Nickel-Catalyzed Decarbonylative Coupling of Aryl Esters and Arylboronic Acids
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A variety of functionalized biaryls can be accessed by coupling aryl and heteroaryl esters with boronic acids in Suzuki-Miyaura-type decarbonylative cross-coupling catalyzed by an affordable catalyst system composed of Ni(cod)2 and PCy3. The methodology is tolerant of a variety of functional groups and presents an attractive alternative to the use of palladium catalysis currently used in industry to acquire such bis(hetero)aryls, but also reveals challenges associated with nickel catalysis of esters in cross-coupling chemistry.
- Laberge, Nicole A.,Love, Jennifer A.
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p. 5546 - 5553
(2015/09/01)
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- Pd-catalyzed C3-selective arylation of pyridines with phenyl tosylates
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We have discovered that phenyl tosylates can be used to arylate pyridines at the C3-position using a Pd(OAc)2-1,10-phenanthroline catalyst system. We also discovered that the reaction of 4-methylpyridine with naphthyl tosylates occurred on the methyl group instead of at the C3-position. The Royal Society of Chemistry 2013.
- Dai, Fenglin,Gui, Qingwen,Liu, Jidan,Yang, Zhiyong,Chen, Xiang,Guo, Ruqing,Tan, Ze
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supporting information
p. 4634 - 4636
(2013/06/05)
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- De novo synthesis of 1,4-dihydropyridines and pyridines
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An efficient and general method for the synthesis of 1,4-dihydropyridines and pyridines based on a lithiation/isomerization/intramolecular carbolithiation sequence is reported. This procedure provides an efficient, divergent, and straightforward entry to a wide range of polysubstituted dihydropyridines and pyridines starting from readily available N-allyl-ynamides.
- Gati, Wafa,Rammah, Mohamed M.,Rammah, Mohamed B.,Couty, Francois,Evano, Gwilherm
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p. 9078 - 9081
(2012/07/13)
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- Intramolecular carbolithiation of N-allyl-ynamides: An efficient entry to 1,4-dihydropyridines and pyridines - Application to a formal synthesis of sarizotan
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We have developed a general synthesis of polysubstituted 1,4-dihydropyridines and pyridines based on a highly regioselective lithiation/6-endo-dig intramolecular carbolithiation from readily available N-allyl-ynamides. This reaction, which has been successfully applied to the formal synthesis of the anti-dyskinesia agent sarizotan, further extends the use of ynamides in organic synthesis and further demonstrates the synthetic efficiency of carbometallation reactions.
- Gati, Wafa,Rammah, Mohamed M.,Rammah, Mohamed B.,Evano, Gwilherm
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p. 2214 - 2222
(2013/02/23)
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- Ligand-promoted C3-selective arylation of pyridines with Pd catalysts: Gram-scale synthesis of (±)-preclamol
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The first example of Pd-catalyzed, C3-selective arylation of unprotected pyridines has been developed by employing a catalytic system consisting of Pd(OAc)2 and 1,10-phenanthroline. This protocol provides an expeditious route to an important class of 3-arylpyridines and 3-arylpiperidines frequently found in bioactive compounds. A brief synthesis of the drug molecule (±)-preclamol is also reported.
- Ye, Mengchun,Gao, Guo-Lin,Edmunds, Andrew J. F.,Worthington,Morris, James A.,Yu, Jin-Quan
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supporting information; experimental part
p. 19090 - 19093
(2012/01/07)
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- Micellar catalysis of Suzuki-Miyaura cross-couplings with heteroaromatics in water
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(Chemical Equation Presented) Pd-catalyzed couplings involving several heteroaromatic halides (bromides and chlorides) as well as boronic acids can be done under exceedingly mild conditions (between rt and 40 °C) in pure water using commercially available Pd catalysts and PTS, a nanomicelle-forming amphiphile.
- Lipshutz, Bruce H.,Abela, Alexander R.
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supporting information; experimental part
p. 5329 - 5332
(2009/06/06)
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- Air-stable and highly active dendritic phosphine oxide-stabilized palladium nanoparticles: Preparation, characterization and applications in the carbon-carbon bond formation and hydrogenation reactions
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Dendrimer-stabilized palladium nanoparticles were formed in the reduction of palldium bis-(acetylacetonate) [Pd(acac)2] in the presence of phosphine dendrimer ligands using hydrogen in tetrahydrofuran. The resulting Pd nanoparticles were characterized by TEM, 31P NMR and 31P MAS NMR. The results indicated that the dendritic phosphine ligandswere oxidized to phosphine oxides. These dendrimer-stabilized Pd nanoparticles were demonstrated to be efficient catalysts for Suzuki and Stille coupling reactionsand hydrogenations. The dendritic wedges served as a stabilizer for keeping the nanoparticlesfrom aggregating, and asa vehicle for facilitating the separation and/or the recycling of the Pd catalyst. In the case of the Suzuki coupling reaction, these Pd nanoparticles exhibited high catalytic efficiency (TON up to 65,000) and air stability as compared with the commonly used homogeneous catalyst tetrakis(triphenylphosphine)palladium [Pd-(PPh 3)4]. In addition, the results obtained from the bulky dendritic substrate suggest that the Pd nanoparticles might act asres ervoir of catalytically active species, and that the reaction is actually catalyzed by the soluble Pd(0) and/or Pd(II) species leached from the nanoparticle surface.
- Wu, Lei,Li, Zhi-Wei,Zhang, Feng,He, Yan-Mei,Fan, Qing-Hua
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experimental part
p. 846 - 862
(2009/05/07)
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- Self-Assembly of 3-[4′-(Diethylboryl)phenyl]pyridine and 3-[3′-(Diethylboryl)phenyl]pyridine: Synthesis, Structural Features, and Stability in Solution
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The self-assembly of 3-[4′-(diethylboryl)phenyl]pyridine (3) and 3-[3′-(diethylboryl)phenyl]pyridine (4) was investigated by 1H and 11B NMR spectroscopies and vapor pressure osmometry. It can be seen that in solution 3 affords an equilibrium mixture of oligomers including a cyclic trimer as a major component via intermolecular boron-nitrogen coordination bonds, which is supported by temperature-, concentration-, and solvent-dependent behaviors of 3. In contrast, 4 seems to afford a mixture of oligomers including a cyclic dimer in solution. Judging from the low coalescence temperature in variable-temperature NMR in toluene-d8 and easy scrambling with the corresponding 3-[(diethylboryl)pheny]-5-methoxypyridines at ambient temperature, it is concluded that the intermolecular boron-nitrogen coordination bonds made by 3 or 4 are weaker than those formed by 3-(diethylboryl)pyridine (1) or 2-(diethylboryl)-5-methylpyridine (2). Poor thermal stability was supported by electrospray mass spectrometry and structural analyses utilizing a semi-empirical molecular orbital calculation AM1. It is noted that in the assembly of 4 there is a tendency to maintain high tetrahedral character at the boron atom in the complex at the expense of strain energy. Thus, these features of 3 and 4 in solution are in marked contrast to those of 1 and 2.
- Wakabayashi, Shigeharu,Sugihara, Yoshikazu,Takakura, Katsuto,Murata, Shigeru,Tomioka, Hideo,Ohnishi, Shiho,Tatsumi, Kazuyuki
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p. 6999 - 7008
(2007/10/03)
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