15827-72-2Relevant academic research and scientific papers
Investigation of catalyst-transfer condensation polymerization for the synthesis of n-type π-conjugated polymer, poly(2-dioxaalkylpyridine-3,6-diyl)
Nanashima, Yutaka,Shibata, Rena,Miyakoshi, Ryo,Yokoyama, Akihiro,Yokozawa, Tsutomu
, p. 3628 - 3640 (2012)
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
Highly Dispersed Palladium Nanoparticle-Loaded Magnetic Catalyst (FeS@EP–AG–Pd) for Suzuki Reaction in Water
Sarvi, Iraj,Gholizadeh, Mostafa,Izadyar, Mohammad
, p. 1162 - 1171 (2017)
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.].
Carbon coated copper nanostructures as a green and ligand free nanocatalyst for Suzuki cross-coupling reaction
Lamei, Kamran,Eshghi, Hossein,Bakavoli, Mehdi,Rounaghi, Seyyed Amin,Esmaeili, Elaheh
, p. 40 - 45 (2017)
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.
Robust photocatalytic water reduction with cyclometalated Ir(iii) 4-vinyl-2,2′-bipyridine complexes
Metz, Stefan,Bernhard, Stefan
, p. 7551 - 7553 (2010)
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.
Highly dispersed copper/ppm palladium nanoparticles as novel magnetically recoverable catalyst for Suzuki reaction under aqueous conditions at room temperature
Lamei, Kamran,Eshghi, Hossein,Bakavoli, Mehdi,Rostamnia, Sadegh
, (2017)
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.
Pd–Ni bimetallic catalyst supported on dendrimer-functionalized magnetic graphene oxide for efficient catalytic Suzuki-Miyaura coupling reaction
Masteri-Farahani, Majid,Niakan, Mahsa
, (2022/01/26)
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
Coumarin-pyridine push-pull fluorophores: Synthesis and photophysical studies
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.
, (2021/11/11)
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.
Discovery of 9,10-dihydrophenanthrene derivatives as SARS-CoV-2 3CLpro inhibitors for treating COVID-19
Zhang, Jian-Wei,Xiong, Yuan,Wang, Feng,Zhang, Fu-Mao,Yang, Xiaodi,Lin, Guo-Qiang,Tian, Ping,Ge, Guangbo,Gao, Dingding
, (2021/12/09)
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.
Diastereoselective and Stereodivergent Synthesis of 2-Cinnamylpyrrolines Enabled by Photoredox-Catalyzed Iminoalkenylation of Alkenes
Shen, Xu,Huang, Congcong,Yuan, Xiang-Ai,Yu, Shouyun
, p. 9672 - 9679 (2021/03/16)
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.
METHOD OF PRODUCING UNSYMMETRICAL DISUBSTITUTED PYRIDINE COMPOUNDS
-
, (2021/01/12)
The present invention relates to a method for producing an asymmetric disubstituted pyridine compound using a position selective Suzuki-Miyaura coupling reaction.
