- Investigation of catalyst-transfer condensation polymerization for the synthesis of n-type π-conjugated polymer, poly(2-dioxaalkylpyridine-3,6-diyl)
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Kumada-Tamao coupling polymerization of 6-bromo-3-chloromagnesio-2-(3-(2- methoxyethoxy)propyl)pyridine 1 with a Ni catalyst and Suzuki-Miyaura coupling polymerization of boronic ester monomer 2, which has the same substituted pyridine structure, with tBu3PPd(o-tolyl)Br were investigated for the synthesis of a well-defined n-type π-conjugated polymer. We first carried out a model reaction of 2,5-dibromopyridine with 0.5 equivalent of phenylmagnesium chloride in the presence of Ni(dppp)Cl2 and then observed exclusive formation of 2,5-diphenylpyridine, indicating that successive coupling reaction took place via intramolecular transfer of Ni(0) catalyst on the pyridine ring. Then, we examined the Kumada-Tamao polymerization of 1 and found that it proceeded homogeneously to afford soluble, regioregular head-to-tail poly(pyridine-2,5-diyl), poly(3-(2-(2-(methoxyethoxy)propyl) pyridine) (PMEPPy). However, the molecular weight distribution of the polymers obtained with several Ni and Pd catalysts was very broad, and the matrix-assisted laser desorption ionization time-of-flight mass spectra showed that the polymer had Br/Br and Br/H end groups, implying that the catalyst-transfer polymerization is accompanied with disproportionation. Suzuki-Miyaura polymerization of 2 with tBu3PPd(o-tolyl)Br also afforded PMEPPy with a broad molecular weight distribution, and the tolyl/tolyl-ended polymer was a major product, again indicating the occurrence of disproportionation. Copyright
- Nanashima, Yutaka,Shibata, Rena,Miyakoshi, Ryo,Yokoyama, Akihiro,Yokozawa, Tsutomu
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Read Online
- Highly Dispersed Palladium Nanoparticle-Loaded Magnetic Catalyst (FeS@EP–AG–Pd) for Suzuki Reaction in Water
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Abstract: In this work, an efficient epichlorohydrin–aminoguanidine-modified Fe3O4@SiO2 magnetic nanoparticles (FeS@EP–AG–Pd) with highly dispersed Palladium nanoparticles (Pd NPs) was reported for Suzuki reaction in water. After preparation of Fe3O4@SiO2 (FeS), special epichlorohydrin–aminoguanidine linker as a ligand with high content of heteroatoms was covalently bonded onto the FeS MNPs to increase their electron density. PdII ions were then loaded on surface of FeS@EP–AG MNPs and reduced for achieving the uniformly dispersed Pd NPs. FeS@EP–AG–Pd MNPs were performed in Suzuki reaction as an efficient catalyst in water as a green non-toxic solvent. Magnetically separable and recyclable FeS@EP–AG–Pd MNPs were then fully characterized by FTIR, SEM, TEM, TGA, VSM, XRD, and ICP–OES. The heterogeneous catalyst could also easily be recovered and reused with no loss of activity over 6 cycles. Graphical Abstract: [Figure not available: see fulltext.].
- Sarvi, Iraj,Gholizadeh, Mostafa,Izadyar, Mohammad
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Read Online
- Carbon coated copper nanostructures as a green and ligand free nanocatalyst for Suzuki cross-coupling reaction
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In this work, carbon coated copper nanoparticles and nanowires were synthesized as a ligand free nanocatalyst that naturally contains ppm levels of Pd with no post-modification via a two-steps reduction-hydrothermal process. Transmittance electron microscope (TEM), scanning electron microscope (SEM), X-ray diffraction, inductively coupled plasma optical emission spectrometry (ICP-OES), and Raman spectroscopy were employed for the characterization of the nano-catalyst. The utilization of the synthesized Cu/C nano-catalyst in Suzuki cross coupling reaction showed a high performance in the synthesis of various biaryls in water. Moreover, this catalyst reused successfully with no significant yield decrease even after four subsequently runs.
- Lamei, Kamran,Eshghi, Hossein,Bakavoli, Mehdi,Rounaghi, Seyyed Amin,Esmaeili, Elaheh
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Read Online
- Robust photocatalytic water reduction with cyclometalated Ir(iii) 4-vinyl-2,2′-bipyridine complexes
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Novel [Ir(CN)2(NN)]+ complexes with NN ligands containing vinyl groups were synthesized resulting in quintupled turn-over numbers for the photocatalytic hydrogen production compared to the analogous non-vinyl compounds.
- Metz, Stefan,Bernhard, Stefan
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Read Online
- Highly dispersed copper/ppm palladium nanoparticles as novel magnetically recoverable catalyst for Suzuki reaction under aqueous conditions at room temperature
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An efficient procedure based on arginine-modified Fe3O4@carbon magnetic nanoparticles (FCA MNPs) with highly dispersed copper nanoparticles (Cu NPs) and 92.8?ppm of Pd is reported for room temperature Suzuki reaction. For enhancing the activity of this Cu-based heterogeneous catalyst, special arginine amino acid as a ligand with high content of heteroatoms was immobilized onto the Fe3O4@carbon MNPs to increase the electron density. Cu(II) ions were then loaded on the surface of the FCA MNPs and reduced to achieve uniformly dispersed Cu NPs. An aqueous mixture of metal hydroxides such as KOH, Ba(OH)2, Ca(OH)2, Mg(OH)2 as a green, non-toxic and basic medium was used for the Suzuki reaction at room temperature. This catalyst could also be recovered and reused with no loss of activity over six successful runs.
- Lamei, Kamran,Eshghi, Hossein,Bakavoli, Mehdi,Rostamnia, Sadegh
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Read Online
- Coumarin-pyridine push-pull fluorophores: Synthesis and photophysical studies
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A series of coumarin-pyridine-based push-pull fluorophores were prepared starting from 1,2,4-triazines by using direct C-H functionalization (SNH-reaction)–Diels-Alder–retro Diels-Alder domino reaction sequence. This efficient synthetic strategy allowed to obtain a series of 19 coumarin-pyridine fluorophores. Their photophysical properties were studied. While pyridine-substituted derivatives of 4-alkylcoumarins may be considered as alternative to coumarin dyes characterized by emission maxima mainly in a visible region with wavelengths of 402–415 nm, absorption in the UV range at 210–307 nm, and good photoluminescence quantum yields of 6–19%, all the derivatives of 4-phenylcoumarin did not exhibit any noticeable fluorescence. More detailed photophysical studies were carried out for two the most representative derivatives of 4-alkyl-coumarin-pyridines to demonstrate their positive solvatochromism, and the collected data were analyzed by using Lippert-Mataga equation, as well as Kosower and Dimroth/Reichardt scales. The obtained results demonstrate that the combining two chromophore systems, such as 2,5-diarylpyridine and coumarin ones, is promising in terms of improving the photophysical properties of the new coumarin-pyridine hybrid compounds.
- Chupakhin, Oleg N.,Fatykhov, Ramil F.,Khalymbadzha, Igor A.,Kopchuk, Dmitry S.,Nikonov, Igor L.,Savchuk, Maria I.,Sharapov, Ainur D.,Shtaitz, Yaroslav K.,Starnovskaya, Ekaterina S.,Zyryanov, Grigory V.
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- Discovery of 9,10-dihydrophenanthrene derivatives as SARS-CoV-2 3CLpro inhibitors for treating COVID-19
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The epidemic coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has now spread worldwide and efficacious therapeutics are urgently needed. 3-Chymotrypsin-like cysteine protease (3CLpro) is an indispensable protein in viral replication and represents an attractive drug target for fighting COVID-19. Herein, we report the discovery of 9,10-dihydrophenanthrene derivatives as non-peptidomimetic and non-covalent inhibitors of the SARS-CoV-2 3CLpro. The structure-activity relationships of 9,10-dihydrophenanthrenes as SARS-CoV-2 3CLpro inhibitors have carefully been investigated and discussed in this study. Among all tested 9,10-dihydrophenanthrene derivatives, C1 and C2 display the most potent SARS-CoV-2 3CLpro inhibition activity, with IC50 values of 1.55 ± 0.21 μM and 1.81 ± 0.17 μM, respectively. Further enzyme kinetics assays show that these two compounds dose-dependently inhibit SARS-CoV-2 3CLpro via a mixed-inhibition manner. Molecular docking simulations reveal the binding modes of C1 in the dimer interface and substrate-binding pocket of the target. In addition, C1 shows outstanding metabolic stability in the gastrointestinal tract, human plasma, and human liver microsome, suggesting that this agent has the potential to be developed as an orally administrated SARS-CoV-2 3CLpro inhibitor.
- Zhang, Jian-Wei,Xiong, Yuan,Wang, Feng,Zhang, Fu-Mao,Yang, Xiaodi,Lin, Guo-Qiang,Tian, Ping,Ge, Guangbo,Gao, Dingding
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- Pd–Ni bimetallic catalyst supported on dendrimer-functionalized magnetic graphene oxide for efficient catalytic Suzuki-Miyaura coupling reaction
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A novel type of dendritic structure was grown on the magnetic graphene oxide nanocomposite surface through thiol-ene click reaction. The resulting nanocomposite was utilized as a support for immobilizing Pd–Ni bimetallic nanoparticles, which were employed
- Masteri-Farahani, Majid,Niakan, Mahsa
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- Diastereoselective and Stereodivergent Synthesis of 2-Cinnamylpyrrolines Enabled by Photoredox-Catalyzed Iminoalkenylation of Alkenes
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A photoredox-catalyzed iminoalkenylation of γ-alkenyl O-acyl oximes has been developed. Readily available alkenylboronic acids serve as alkenylation reagents, leading to densely functionalized pyrrolines. Both (E)- and (Z)-cinnamylpyrrolines are accessible depending on the reaction solvent. In dichloromethane, (E)-cinnamylpyrrolines are produced through a photoredox-mediated single-electron-transfer process. In tetrahydrofuran, (Z)-cinnamylpyrrolines are generated by photocatalytic contra-thermodynamic E-to-Z isomerization of (E)-cinnamylpyrrolines though an energy-transfer pathway. Two stereocenters are established with complete diastereoselectivity and only one diastereomer is isolated.
- Shen, Xu,Huang, Congcong,Yuan, Xiang-Ai,Yu, Shouyun
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p. 9672 - 9679
(2021/03/16)
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- METHOD OF PRODUCING UNSYMMETRICAL DISUBSTITUTED PYRIDINE COMPOUNDS
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The present invention relates to a method for producing an asymmetric disubstituted pyridine compound using a position selective Suzuki-Miyaura coupling reaction.
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- Highly Selective Room-Temperature Suzuki-Miyaura Coupling of Bromo-2-sulfonyloxypyridines for Unsymmetrical Diarylpyridines
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A new and mild synthetic approach has been developed for the synthesis of pharmaceutically important unsymmetrical diarylpyridines via chemoselective Suzuki-Miyaura coupling reactions of bromo-2-sulfonyloxypyridines. Most reactions allow for facile access to aryl-2-sulfonyloxypyridines at room temperature in yields of 5-99% with excellent chemoselectivity in the presence of Pd(OAc)2 (2.0 mol %) and Ad2BnP (2.4 mol %). The second arylation of the remaining tosyl or triflyl group in the monoarylpyridine derivatives obtained was successfully accomplished for the synthesis of unsymmetrical 2,3-, 2,4-, 2,5-, and 2,6-diarylpyridine derivatives. Furthermore, a one-pot synthesis of unsymmetrical diarylpyridines starting from bromo-2-sulfonyloxypyridine was accomplished to demonstrate the practical convenience. Finally, with this method, an antibacterial agent, a topoisomerase inhibitor, and etoricoxib, a nonsteroidal anti-inflammatory drug, were successfully synthesized from the corresponding bromo-2-hydroxypyridines in overall yields of 80, 86, and 49%, respectively.
- Jeon, Young-Kyo,Kim, Seo-Eun,Kim, Won-Suk,Lee, Jae-Yeon
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p. 7399 - 7412
(2020/07/07)
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- Preparation method and application of a class of cyclometalated platinum coordination compounds
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The invention discloses a preparation method and application of a class of cyclometalated platinum coordination compounds, and belongs to the field of phosphorescent materials. According to the invention, seven platinum coordination compounds are synthesi
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Paragraph 0038-0040
(2020/10/30)
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- Novel combination of host compound and dopant compound and organic electroluminescence device comprising same
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The present invention relates to a specific combination of a dopant compound and a host compound, and an organic electroluminescent device comprising the same. The organic electroluminescent device ofthe present invention emits yellow-green light; lowers the driving voltage of the device by improving the current characteristic of the device; and improves power efficiency and operational lifespan.
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Paragraph 0087-0090; 0121-0124
(2019/12/10)
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- Efficient construction of C–C bonds from aryl halides/aryl esters with arylboronic acids catalysed by palladium(II) thiourea complexes
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A new set of palladium(II) complexes comprising phenyl(thiazolyl)thiourea ligands have been successfully synthesized and characterized with the aid of analytical as well as spectral (IR, UV–visible and NMR) methods. A distorted square-planar geometry with N^S coordination mode of thiourea ligands in the new palladium complexes was corroborated by single-crystal X-ray diffraction methods. Interestingly, the palladium(II) thiourea complexes showed the highest catalytic activity with 0.1 mol% catalyst loading in Suzuki–Miyaura cross-coupling reactions utilizing a range of aryl bromides/unactivated aryl chlorides with arylboronic acids as coupling partners in aqueous–organic media. Syntheses of diaryl ketones using aryl esters and arylboronic acids as coupling partners were also achieved with low catalyst loading within 20 h. The potential of our catalyst was demonstrated by its wide substrate scope, low catalyst loadings and high isolated yield. Moreover, the influences of key parameters like solvent, base, temperature and catalyst loading were also investigated.
- Thimma Sambamoorthy, Manikandan,Rengan, Ramesh,Jan Grzegorz, Malecki
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- N-heterocyclic carbene enabled rhodium-catalyzed ortho C(sp2)-H borylation at room temperature
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We report a rhodium-catalyzed ortho C(sp2)-H borylation of 2-phenylpyridines using commercially available N-heterocyclic carbenes (NHCs) as ligand and pinacolatodiboron (B2pin2) as borylating reagent. The reaction could take place at room temperature, tolerating a wide range of functionalities and affording ortho borylated products in moderate to excellent yields. The current method is also applicable to gram-scale reaction with reduced catalyst loading.
- Zhong, Lei,Zong, Zhi-Hong,Wang, Xi-Cun
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supporting information
p. 2547 - 2552
(2019/03/27)
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- Visible Light Induced Rhodium(I)-Catalyzed C?H Borylation
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An efficient visible light induced rhodium(I)-catalyzed regioselective borylation of aromatic C?H bonds is reported. The photocatalytic system is based on a single NHC?RhI complex capable of both harvesting visible light and enabling the bond breaking/forming at room temperature. The chelating nature of the NHC-carboxylate ligand was critical to ensure the stability of the RhI complex and to provide excellent photocatalytic activities. Experimental mechanistic studies evidenced a photooxidative ortho C?H bond addition upon irradiation with blue LEDs, leading to a cyclometalated RhIII-hydride intermediate.
- Thongpaen, Jompol,Manguin, Romane,Dorcet, Vincent,Vives, Thomas,Duhayon, Carine,Mauduit, Marc,Baslé, Olivier
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supporting information
p. 15244 - 15248
(2019/10/22)
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- Nickel(II)- and Palladium(II)-NHC Complexes from Hydroxypyridine Functionalized C,O Chelate Type Ligands: Synthesis, Structure, and Catalytic Activity toward Kumada-Tamao-Corriu Reaction
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Hydroxypyridine functionalized imidazolium salts (2a-c) have been prepared in a one pot neat reaction between alkyl/aryl imidazoles and 2-chloro-3-hydroxypyridine. The imidazolium salts were used as proligands for the synthesis of new Ni(II) (3a, 3c, and 3c′) and Pd(II) NHC (4a-4c) complexes. Complexes, 3a, 3c, and 4a-4c are four coordinated with square planar geometry around the metal center and feature the C,O chelation of the heterobidentate NHC ligands, using carbene atoms and the O atom of the hydroxypyridine arm. Depending upon the steric bulk of the alkyl/aryl substituents on the ligand, either cis (3a and 4a) or trans (3c, 4b, and 4c) complexes are obtained. For the nickel complex with the 2c ligand, two different isomeric forms (3c and 3c′) were observed. In 3c, both the NHC ligands are bound via C2 and O atoms of the hydroxypyridine arm, whereas, in 3c′, one of the two ligands binds via C4 and N atoms of the hydroxypyridine side arm. 3c′ represents a unique square planar complex with the central metal atom bound simultaneously to both normal and abnormal carbenes. All the five complexes, except 3c′, were evaluated as catalysts for the Kumada-Tamao-Corriu cross-coupling reaction between phenylmagnesium bromide and different aryl chlorides at room temperature.
- Bhat, Irshad Ahmad,Avinash, Iruthayaraj,Anantharaman, Ganapathi
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p. 1699 - 1708
(2019/03/07)
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- A palladium complex confined in a thiadiazole-functionalized porous conjugated polymer for the Suzuki-Miyaura coupling reaction
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Porous organic polymers (POPs) with well-distributed and tunable functional groups acting as ligands for specific reactions are promising supports for confining useful novel metals such as Pd, Au, and Pd. Herein, a thiadiazole-containing POP has been successfully synthesized and used for immobilizing Pd species. Pd immobilized inside the micropores (2.3 nm) of the POP material is easily prepared owing to a large amount of the strong anchoring group, thiadiazole, which is intrinsically distributed in the as-prepared POP. The rigid thiadiazole-containing polymer can stabilize the central metal rather than poisoning it. The as-prepared catalyst shows excellent catalytic activity in Suzuki-Miyaura coupling reactions under mild reaction conditions and low catalyst loading. Importantly, the intrinsically distributed thiadiazole ligands can stabilize the Pd moiety, preventing aggregation and leaching, and afford excellent catalytic lifetimes. Consequently, the catalyst can be reused 10 times without a significant loss of its catalytic activity.
- Qian, Yingjie,Jeong, Sang Yung,Baeck, Sung-Hyeon,Jin, Myung-Jong,Shim, Sang Eun
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p. 33563 - 33571
(2019/11/13)
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- N-Silylenamines as Reactive Intermediates: Hydroamination for the Modular Synthesis of Selectively Substituted Pyridines
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A modular and selective synthesis of mono-, di-, tri-, tetra-, and pentasubstituted pyridines is reported. Hydroamination of alkynes with N-silylamine using a bis(amidate)bis(amido)titanium(IV) precatalyst furnishes the regioselective formation of N-silylenamines. Addition of α,β-unsaturated carbonyls to the crude mixtures followed by oxidation affords 47 examples of pyridines in yields of up to 96%. This synthetic route allows for the synthesis of diverse pyridines containing variable substitution patterns, including pharmaceutically relevant 2,4,5-trisubstituted pyridines, using this one-pot protocol.
- Lui, Erica K. J.,Hergesell, Daniel,Schafer, Laurel L.
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supporting information
p. 6663 - 6667
(2018/11/21)
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- Transition-Metal-Free Decarboxylative Arylation of 2-Picolinic Acids with Arenes under Air Conditions
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A facile, transition-metal-free, and direct decarboxylative arylation of 2-picolinic acids with simple arenes is described. The oxidative decarboxylative arylation of 2-picolinic acids with arenes proceeds readily via N-chloro carbene intermediates to afford 2-arylpyridines in satisfactory to good yields under transition-metal-free conditions. This new type of decarboxylative arylation is operationally simple and scalable and exhibits high functional-group tolerance. Various synthetically useful functional groups, such as halogen atoms, methoxycarbonyl, and nitro, remain intact during the decarboxylative arylation of 2-picolinic acids.
- Zhang, Xitao,Feng, Xiujuan,Zhou, Chuancheng,Yu, Xiaoqiang,Yamamoto, Yoshinori,Bao, Ming
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p. 7095 - 7099
(2018/11/23)
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- Preparation method of phenyl triazine compound and preparation method of phenyl pyridine compound
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The invention relates to the technical field of compound synthesis, in particular to a preparation method of phenyl triazine compound and preparation method of the phenyl pyridine compound, the preparation method of phenyl triazine compound and preparation method of phenyl pyridine compound takes the compound having the structure represented by the formula (I), the compound having the structure represented by the formula (II), organic protic acid, the ammonium salt and the first organic solvent to undergo nucleophilic addition reaction and ring reaction to prepare the phenyl triazine compoundwith the structure shown by the formula (III), no noble metal catalyst is needed in the reaction, the reaction yield and the purity are higher, and then carries out inverse Diels-Alder reaction with the phenyl triazine compound prepared by the above method with the structure shown in the formula (III), the norbornene diene and the second organic solvent to obtain the phenyl pyridine compound withthe structure represented by the formula (VI), wherein no noble metal catalyst is needed in the reaction, the reaction yield and purity are both high. Besides, the preparation method provided is concise in route, good in process controllability, low in cost and easy for industrial production.
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Paragraph 0104; 0106
(2018/10/19)
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- Efficient Suzuki-Miyaura mono-arylation of symmetrical diiodo(hetero)arenes
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A reliable protocol for converting 1,4-diiodo-2,3,5,6-tetrafluorobenzene into 1-(hetero)aryl-4-iodo-2,3,5,6-tetrafluorobenzene derivatives has been lacking in the literature. We have identified optimal conditions to achieve this conversion in good yields and have minimized formation of the bis-coupling product. The newly identified protocol involving the use of a syringe pump has been extended to other symmetrical diiodo(hetero)arenes.
- Sapegin, Alexander,Krasavin, Mikhail
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supporting information
p. 1948 - 1951
(2018/04/16)
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- Denitrogenative palladium-catalyzed coupling of aryl halides with arylhydrazines under mild conditions
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The development of a method for the Pd(ii)-catalyzed denitrogenative coupling of arylhydrazines to give functionalized biaryls in good yield, using aryl bromides or aryl iodides as convenient and inexpensive aryl sources, is reported. High functional group tolerance is demonstrated for electronically distinct arylhydrazines as well as aryl halides. The desired products were isolated in good to excellent yields for 58 examples. Control experiments and mechanism studies revealed that the transformation undergoes a base-promoted Pd-catalyzed process.
- Chang, Sheng,Dong, Lin Lin,Song, Hai Qing,Feng, Bo
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supporting information
p. 3282 - 3288
(2018/05/15)
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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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- Biscarbazole derivative host materials and green emitter for OLED emissive region
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An organic electroluminescence device utilizes a novel combination comprising one or more biscarbazole derivative compounds as the phosphorescent host material in combination with a green phosphorescent dopant material in the light emitting region of the device, where the biscarbazole derivative compounds are represented by a formula (1A) or (1B) below; where A1 represents a substituted or unsubstituted nitrogen-containing heterocyclic group having 1 to 30 ring carbon atoms; A2 represents a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms, or substituted or unsubstituted nitrogen-containing heterocyclic group having 1 to 30 ring carbon atoms; X1 and X2 each are a linking group; Y1 to Y4 each represent a substituent; p and q represent an integer of 1 to 4; and r and s represent an integer of 1 to 3; and the green phosphorescent dopant material is a phosphorescent organometallic complex having a chemical structure represented by LL′L″M wherein M is a metal that forms octahedral complexes, L, L′, and L″ are equivalent or inequivalent bidentate ligands wherein each L comprises a substituted or unsubstituted phenylpyridine ligand coordinated to M through an sp2 hybridized carbon and N; and, one of L, L′ and L″ is different from at least one of the other two.
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Page/Page column 106
(2018/05/24)
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- Directed: Ortho C-H borylation catalyzed using Cp?Rh(iii)-NHC complexes
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Cp?Rh(NHC) complexes with bulky chiral bidentate NHC-carboxylate ligands were efficiently synthesized and fully characterized including solid-state structures. These unprecedented rhodium(iii) complexes demonstrated high selectivity in pyridine-directed ortho-C-H borylation of arenes under mild conditions.
- Thongpaen, Jompol,Schmid, Thibault E.,Toupet, Loic,Dorcet, Vincent,Mauduit, Marc,Baslé, Olivier
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supporting information
p. 8202 - 8205
(2018/07/29)
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- Synthesis of 2,3,6-trisubstituted pyridines by transition-metal free cyclization of 1,3-diynes with amino acids
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Amino acids are firstly employed in transition-metal free heterocyclization reaction of 1,3-diynes in the presence of K3PO4 and DMSO at 120?°C. This method produces 2,3,6-trisubstituted pyridines with up to 86% yield. The –CO2H group on the amino acids is crucial for this heterocyclization reaction. The mechanism of such a heterocyclization reaction is discussed, as well.
- Zhou, Gang,Zhao, Xiaoming,Dan, Wenyan
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supporting information
p. 3085 - 3088
(2017/07/17)
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- NOVEL COMPOUNDS
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The present invention relates to novel compounds of formula (I) and methods for the manufacture of inhibitors of deubiquitylating enzymes (DUBs). In particular, the invention relates to the inhibition of ubiquitin C-terminal hydrolase 30 or ubiquitin spec
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Page/Page column 68; 69
(2017/09/08)
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- Chemoselective Synthesis of Polysubstituted Pyridines from Heteroaryl Fluorosulfates
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A selection of heteroaryl fluorosulfates were readily synthesized using commercial SO2F2 gas. These substrates are highly efficient coupling partners in the Suzuki reaction. Through judicious selection of Pd catalysts the fluorosulfate functionality is differentiated from bromide and chloride; the order of reactivity being: -Br> -OSO2F> -Cl. Exploiting this trend allowed the stepwise chemoselective synthesis of a number of polysubstituted pyridines, including the drug Etoricoxib. A selection of heteroaryl fluorosulfates were readily synthesized using commercial SO2F2 gas. These substrates are highly efficient coupling partners in the Suzuki reaction. Through judicious selection of Pd catalysts the fluorosulfate functionality is differentiated from bromide and chloride; the order of reactivity being: -Br> -OSO2F> -Cl. Exploiting this trend allowed the stepwise chemoselective synthesis of a number of polysubstituted pyridines, including the drug Etoricoxib.
- Zhang, Enxuan,Tang, Jiaze,Li, Suhua,Wu, Peng,Moses, John E.,Sharpless, K. Barry
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p. 5692 - 5697
(2016/04/20)
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- POPd/TBAB co-catalyzed Suzuki cross-coupling reaction of heteroaryl chlorides/bromides with 4-fluorophenylboronic acid in water
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An organic solvent free and efficient heterogeneous synthesis for bridging heteroaryl halides and 4-fluorophenylboronic acid was studied in aqueous media according to the Suzuki cross-coupling protocol. High yields of heteroaryl-aryl fluorides were successfully obtained with: chloro-/bromo-substituted pyridine, thiophene, indole, and inzole in neat water using palladium phosphinous acid complexes (POPd)/tetrabutylammonium bromide (TBAB) as co-catalysts. A possible mechanism for the heterogeneous coupling reaction is proposed and discussed according to the function of the TBAB interphases. The notable properties of the reported method are highly co-catalytic activity, hetero-atom tolerance, simple separating procedure and little environmental disposal impact.
- Li, Ben,Zhang, Zhiqiang
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p. 637 - 644
(2016/02/19)
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- Visible-light-promoted and one-pot synthesis of phenanthridines and quinolines from aldehydes and o -Acyl hydroxylamine
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A one-pot synthesis of phenanthridines and quinolines from commercially available or easily prepared aldehydes has been reported. O-(4-Cyanobenzoyl)hydroxylamine was utilized as the nitrogen source to generate O-acyl oximes in situ with aldehydes catalyzed by Bronsted acid. O-Acyl oximes were then subjected to visible light photoredox catalyzed cyclization via iminyl radicals to furnish aza-arenes. A variety of phenanthridines and quinolines have been prepared assisted by Bronsted acid and photocatalyst under visible light at room temperature with satisfactory yields.
- An, Xiao-De,Yu, Shouyun
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supporting information
p. 2692 - 2695
(2015/06/16)
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- PHOSPHORESCENT MATERIALS
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Novel organic compounds containing a twisted aryl group are provided. In particular, the compounds provided contain a 2-phenylpyridine ligand having a twisted aryl group on the pyridine portion of the ligand. The compounds may be used in organic light emitting devices, particularly as emitting dopants. Devices comprising the compounds containing twisted aryl may demonstrate improved color, efficiency, stability and manufacturing. Additionally, methods are provided for making homoleptic Ir (III) compounds which may contain a twisted aryl.
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Paragraph 0189; 0190
(2015/11/16)
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- The host compound and a new combination and dopant compd. organic electroluminescence device including the same
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The present invention relates to a specific combination of a dopant compound and a host compound, and an organic electroluminescent device comprising the same. The organic electroluminescent device of the present invention emits yellow-green light; lowers
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Paragraph 0104; 0135-0138
(2016/10/08)
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- A new approach to pyridines through the reactions of methyl ketones with 1,2,4-triazines
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A new route to prepare pyridine derivatives based on inverse electron demand Diels-Alder/retro-Diels-Alder reactions of ketones with 1,2,4-triazines is reported. It is the first time using methyl ketones directly as a dienophile to react with 1,2,4-triazines without enamine intermediates, which is complementary to the classical Boger reaction. This journal is
- Wang, Shu-Wen,Guo, Wei-Si,Wen, Li-Rong,Li, Ming
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p. 59218 - 59220
(2015/02/19)
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- Triarylbismuthanes as threefold aryl-transfer reagents in regioselective cross-coupling reactions with bromopyridines and quinolines
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Cross-coupling studies using bromopyridines and bromoquinolines with triarylbismuths as threefold coupling reagents in substoichiometric amounts under Pd-catalysed conditions are disclosed. The reactivity was high with both mono- and dibromopyridyl substrates, and mono- and bis-couplings were carried out regioselectively. A library of monoaryl and diaryl pyridines was formed in high yields. A one-pot strategy provided a simple and straightforward synthesis of both symmetrical and unsymmetrical diarylpyridines. Arylations of 2-bromo- and 3-bromoquinolines were achieved with triarylbismuth reagents. This study demonstrates that triarylbismuths may be used as threefold arylating reagents for the synthesis of aryl pyridines and quinolines through couplings with bromopyridines and bromoquinolines under Pd-catalysed conditions. Copyright
- Rao, Maddali L.N.,Dhanorkar, Ritesh J.
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p. 5214 - 5228
(2014/10/15)
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- Copper-catalyzed direct C-H arylation of pyridine N-oxides with arylboronic esters: One-pot synthesis of 2-arylpyridines
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The first example of the copper-catalyzed direct C-H arylation of pyridine N-oxides with arylboronic esters has been developed, leading to a wide range of 2-arylpyridines in a one-pot synthesis with moderate to good yields without an additional reductant. This transformation allows for rapid access to a variety of 2-arylpyridines using an inexpensive catalytic system that would be more difficult to access with traditional methods. Thus, this method represents a simple and practical procedure to access 2-arylpyridines.
- Shen, Yan,Chen, Jiuxi,Liu, Miaochang,Ding, Jinchang,Gao, Wenxia,Huang, Xiaobo,Wu, Huayue
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supporting information
p. 4292 - 4295
(2014/04/17)
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- Palladium-catalyzed highly regioselective 2-arylation of 2,x-dibromopyridines and its application in the efficient synthesis of a 17β-HSD1 inhibitor
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2,3- and 2,5-Dibromopyridines reacted with arylboronic acids, catalyzed by Pd(OAc)2/PPh3 in the presence of K2CO 3 in CH3CN/MeOH (2:1) at 50 C for 24 h, to afford 2-arylpyridines in good to high yield
- Zhou, Qizhong,Zhang, Bin,Su, Liangjun,Jiang, Tiansheng,Chen, Rener,Du, Tieqi,Ye, Yuyuan,Shen, Jianfen,Dai, Guoliang,Han, Deman,Jiang, Huajiang
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p. 10996 - 11003
(2014/01/06)
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- Palladium(II) catalyzed Suzuki/Sonogashira cross-coupling reactions of sulfonates: An efficient approach to C2-functionalized pyrimidines and pyridines
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Pyrimidin-2-yl sulfonates, as a reaction partner, can be easily prepared from inexpensive commercial materials and are efficiently cross-coupled with arylboronic acids and terminal alkynes by using Pd(OAc)2-catalyzed Suzuki and Sonogashira reactions. A wide array of C2-functionalized pyrimidines have been prepared in good to excellent yields. 2-Arylpyridines and 2-(oct-1-ynyl)pyridine were also synthesized. An efficient means to synthesize expanded pyrimidin-2-yl conjugated systems was developed by using Pd(OAc) 2-catalyzed cross-coupling reaction of pyrimidin/pyridin-2-yl sulfonates with arylboronic acids and terminal alkynes. Compared with 2-chloropyrimidines, pyrimidin-2-yl sulfonates can be easily prepared from inexpensive commercial materials and the reactions are more efficient. Copyright
- Quan, Zheng-Jun,Jing, Fu-Qiang,Zhang, Zhang,Da, Yu-Xia,Wang, Xi-Cun
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supporting information
p. 7175 - 7183
(2013/11/06)
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- Mn-catalyzed aromatic C-H alkenylation with terminal alkynes
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The first manganese-catalyzed aromatic C-H alkenylation with terminal alkynes is described. The procedure features an operationally simple catalyst system containing commercially available MnBr(CO)5 and dicyclohexylamine (Cy2NH). The reaction occurs readily in a highly chemo-, regio-, and stereoselective manner delivering anti-Markovnikov E-configured olefins in high yields. Experimental study and DFT calculations reveal that (1) the reaction is initiated by a C-H activation step via the cooperation of manganese and base; (2) manganacycle and alkynylmanganese species are the key reaction intermediates; and (3) the ligand-to-ligand H-transfer and alkynyl-assisted C-H activation are the key steps rendering the reaction catalytic in manganese.
- Zhou, Bingwei,Chen, Hui,Wang, Congyang
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p. 1264 - 1267
(2013/03/14)
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- Aryl 5-substitution of a phenyl-pyridine based ligand as a viable way to influence the opto-electronic properties of bis-cyclometalated Ir(iii) heteroleptic complexes
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This manuscript reports on the synthesis, the photophysical study and the electroluminescent properties of a series of heteroleptic cyclometalated iridium(iii) complexes based on 2,5-diaryl-pyridines as C^N cyclometalating ligands and acetylacetonate as ancillary ligand. The complexes were characterised by elemental analysis, ESI-MS, multinuclear NMR, TGA and electrochemistry. Their optical properties were investigated by UV-Vis and photoluminescence. DFT and TD-DFT calculations provided further insights into the effects of the 5-aryl substitution on the electronic and photophysical properties of the new complexes. The presence of suitable π-extended ligands exerts a beneficial effect on the performances of the corresponding solution-processed light-emitting diodes, leading to a maximum brightness of 10620 cd m-2 at a current efficiency of 10.0 cd A-1.
- Grisorio, Roberto,Suranna, Gian Paolo,Mastrorilli, Piero,Mazzeo, Marco,Colella, Silvia,Carallo, Sonia,Gigli, Giuseppe
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p. 8939 - 8950
(2013/07/27)
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- Synthesis of substituted pyridines and quinolines
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A variety of N-vinyl and N-aryl amides were converted to the corresponding pyridine and quinoline derivatives, respectively. Amide activation and nucleophilic addition of copper(I) (trimethylsilyl)acetylide efficiently provided the desired alkynyl imines. Ruthenium-catalyzed protodesilylation and cycloisomerization of these imines gave the corresponding azaheterocycles. Georg Thieme Verlag Stuttgart.
- Hill, Matthew D.,Movassaghi, Mohammad
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p. 1115 - 1119
(2008/02/02)
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- Desulfitative carbon-carbon cross-coupling of thioamide fragments with boronic acids
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A novel and general carbon-carbon cross-coupling reaction between cyclic thioamides and boronic acids is described. The reaction is catalytic in palladium(O) and requires stoichiometric amounts of a copper(I) carboxylate as metal cofactor. The mode of cross-coupling in the reaction of cyclic thioamides with boronic acids is easily tunable between carbon-carbon and carbon-sulfur cross-coupling. While the catalytic palladium(O)/ copper(I) system provides carbon-carbon bond formation with extrusion of sulfur, stoichiometric quantities of copper(II) under air mediate carbon-sulfur bond formation.
- Prokopcova, Hana,Kappe, C. Oliver
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p. 448 - 452
(2008/02/08)
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- Palladium(0)-catalyzed, copper(I)-mediated coupling of boronic acids with cyclic thioamides. Selective carbon-carbon bond formation for the functionalization of heterocycles
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(Chemical Equation Presented) The palladium-catalyzed cross-coupling of cyclic thioamides with arylboronic acids in the presence of stoichiometric amounts of a copper(I) cofactor is described. The desulfitative carbon-carbon cross-coupling protocol is performed under neutral conditions and can be applied to a range of heterocyclic structures with embedded thioamide fragments. Successful carbon-carbon cross-coupling is independent of the ring size, aromaticity/nonaromaticity, the presence of additional heteroatoms, or other functional groups in the starting thioamide structure. Employing controlled microwave irradiation at 100°C, most cross-couplings can be completed within 2 h and proceed in high yields. An advantage of using thioamides as starting materials is die fact that the system can be tuned to an alternative carbon-sulfur cross-coupling pathway by changing to stoichiometric copper(II) under oxidative conditions. Both types of thioamide cross-couplings are orthogonal to the traditional base-catalyzed Suzuki-Miyaura cross-coupling of aryl halides with boronic acids.
- Prokopcova, Hana,Kappe, C. Oliver
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p. 4440 - 4448
(2008/02/05)
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- Synthesis of substituted pyridine derivatives via the ruthenium-catalyzed cycloisomerization of 3-azadienynes
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We describe a two-step conversion of various N-vinyl and N-aryl amides to the corresponding substituted pyridines and quinolines, respectively. The process involves the direct conversion of amides, including sensitive N-vinyl amides, to the corresponding trimethylsilyl alkynyl imines followed by a ruthenium-catalyzed protodesilylation and cycloisomerization. A wide range of new alkynyl imines are prepared and readily converted to the corresponding azaheterocycles. Copyright
- Movassaghi, Mohammad,Hill, Matthew D.
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p. 4592 - 4593
(2007/10/03)
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- NOVEL USE OF TRICYCLIC COMPOUND
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Pharmaceutical compositions for enhancing the expression of apoAI are provided, which are used as medicaments for treatment of cardiovascular diseases on the basis of improving the functions of HDL.Pharmaceutical compositions for enhancing the expression of apoAI which comprises a compound of formula (I): in which X1 and X2 are independently an aryl or heteroaryl that may be optionally substituted, a hydrogen, a halogen, or the like; ring A is a benzene ring or 6-membered aromatic heterocyclic ring containing 1 to 3 N atoms that may be optionally condensed with another aromatic ring; R1 to R4 are independently a hydrogen, a halogen, a lower alkyl, a lower alkoxy or the like; a prodrug thereof, a pharmaceutically acceptable salt or solvate of them are disclosed.
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Page/Page column 14-15; 17
(2008/06/13)
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- Cross Mannich Reaction of Aldehydes; Efficient Synthesis of Substituted Pyridines
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Symmetrically and unsymmetrically substituted pyridines were obtained in highly efficient one-pot procedures starting from α-unbranched aldehydes and iminium salts.
- Winter, Andreas,Risch, Nikolaus
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p. 2667 - 2670
(2007/10/03)
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- Thermal Rearrangement of N-Arylmethyl- and N-Alkyl-2,2-dihalogenocyclopropyl Imines
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An extended study of the thermal isomerization of 1-substituted 2,2-dihalogenocyclopropyl imines is reported.The thermolysis of N-arylmethyl-2,2-dichlorocyclopropanecarbaldimines 15a-h produces 2-aryl- 16a-h and 2-aryl-4-chloro-pyridine derivatives 17a-h, while N-cyclopropyl imines 15i, j yielded N-alyklchloropyrroles.The 2,2-dibromocyclopropane analogue undergoes thermolysis at lower temperatures.An ionic mechanism triggered by the halide ion dissociation is proposed for the thermal rearrangement on the basis of a study using deuterated imine 15m, and the effects of additives and solvents.On the other hand, difluorocyclopropyl imine undergoes a homolytic cleavage of cyclopropane 1,3-bond with lower activation energy than the dichlorocyclopropyl imine, and afforded the N-alykl-3-fluoropyrrole derivative preferentially.
- Kagabu, Shinzo,Ando, Chihaya,Ando, Junko
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p. 739 - 752
(2007/10/02)
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- Coordinated 1-Aza-1,3-butadienes: Stable Intermediates in the Formation of Pyridines from chromium Complexes
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chromium complexes 3a-c rearrange to coordinated 1-aza-1,3-butadienes 6a-c, which undergo cycloadditions with alkynes 7a,c to pyridines 9a, 10a-c. - Key words: Chromium, (β-aminoethenyl)carbene complexes / 1-Aza-1,3-butadienes, co
- Duetsch, Michael,Stein, Frank,Funke, Frank,Pohl, Ehmke,Herbst-Irmer, Regine,Meijere, Armin de
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p. 2535 - 2542
(2007/10/02)
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- Thermolysis of N-Benzyl-2,2-dichlorocylopropanecarboxaldimines: A Novel Ring Enlargement to 2-Phenylpyridines
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Schiff bases of 2,2-dichlorocyclopropanecarbaldehydes with arylmethylamines were pyrolyzed to 2-arylpyridines.Tungsten(VI) oxide promoted the transformation.The reaction pathway is discussed.
- Kagabu, Shinzo,Naruse, Shigemi,Tagami, Yuko,Watanabe, Yasuo
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p. 4275 - 4277
(2007/10/02)
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- A Convenient Palladium-Catalyzed Coupling Approach to 2,5-Disubstituted Pyridines
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2,5-Dibromopyridine has been found to undergo a regioselective palladium-catalyzed coupling reaction with terminal acetylenes and arylzinc halides to give the corresponding 2-alkynyl-5-bromo- and 2-aryl-5-bromopyridines, respectively, in 70percent-90percent isolated yields.To complement this chemistry, the triflate derived from 2-methyl-5-pyridinol was found to participate in a palladium-catalyzed reaction with terminal acetylenes leading to the corresponding 5-alkynyl-2-methylpyridines.These intermediates can be further manipulated to afford a broad range of 2,5-disubstituted pyridines.
- Tilley, Jefferson W.,Zawoiski, Sonja
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p. 386 - 390
(2007/10/02)
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