5396-71-4Relevant academic research and scientific papers
The Mizoroki-Heck reaction in mesoionic 1-butyl-3-methyltetrazolium-5-olate
Araki, Shuki,Hirashita, Tsunehisa,Kurabayashi, Hideaki
, (2021/10/12)
1-Butyl-3-methyltetrazolium-5-olate (1), a mesoionic compound, exists as a liquid at room temperature and can be used as a polar solvent for the Mizoroki-Heck reaction, wherein it has been proven to be a superior solvent to other solvents. The reaction of iodobenzene with ethyl acrylate in the presence of palladium acetate in mesoionic liquid 1 at 40 °C for 24 h gave ethyl cinnamate in 78% yield in the absence of ligands, while the use of other solvents, such as [bmim][BF4], [bmim][PF6], and DMF gave lower yields (43%, 37%, and 17%, respectively) under the same conditions. Heck-type coupling reactions of electron-deficient or electron-rich aryl iodides and bromobenzenes with olefins (15 examples, 7%–97%) were performed in 1. When a phosphine ligand was added to the reaction mixture, aryl bromides could be used, and the mesoionic liquid containing the catalysts could be reused at least five times.
Pd/Cu-Free Cobalt-Catalyzed Suzuki and Heck Using Green Bio-Magnetic Hybrid and DFT-Based Theoretical Study
Hajipour, Abdol R.,Khorsandi, Zahra,Ahmadi, Mehnoosh,Jouypazadeh, Hamidreza,Mohammadi, Bahareh,Farrokhpour, Hossein
, p. 2842 - 2850 (2021/02/01)
Abstract: Several highly efficient and magnetically recyclable cobalt catalytic systems were prepared using magnetic chitosan and some safe and available organic compounds (Co-ligand@MNPs/Ch). The structure of these nanocomposites was confirmed by various physicochemical techniques such as FT-IR, XRD, TGA, VSM, TEM, SEM, CHNS and ICP-OES. These nano composites exhibit remarkable catalytic efficiency for Suzuki and Heck cross-coupling reactions in mild and green reaction conditions. The facile accessibility of starting materials, possible performance in air and eco-friendly conditions are merits of our catalysts. In addition, to describe and go insight to role and effect of ligands present in these catalysts, electrostatic interactions, density functional theory (DFT) model in molecular method were employed. Graphic Abstract: [Figure not available: see fulltext.]
Fabrication of Pd/CuFe2O4 hybrid nanowires: A heterogeneous catalyst for Heck couplings
Lakshminarayana,Mahendar,Ghosal,Sreedhar,Satyanarayana,Subrahmanyam, Ch.
, p. 1646 - 1654 (2018/02/09)
The development of environmentally benign transformations is indispensable in organic synthesis. Herein, a hybrid heterogeneous catalyst, palladium(0) on copper ferrite nanowires, has been synthesized, characterized, and for the first time, employed in the Jeffrey Heck reaction between iodoarenes and allylic alcohols, and good to excellent yields have been obtained. In addition, the catalyst was found to be suitable for the usual Heck coupling. The nanocatalyst was recovered and reused up-to multiple runs without any noticeable loss of its catalytic activity.
Ligand-accelerated non-directed C-H functionalization of arenes
Wang, Peng,Verma, Pritha,Xia, Guoqin,Shi, Jun,Qiao, Jennifer X.,Tao, Shiwei,Cheng, Peter T. W.,Poss, Michael A.,Farmer, Marcus E.,Yeung, Kap-Sun,Yu, Jin-Quan
, p. 489 - 493 (2017/11/28)
The directed activation of carbon-hydrogen bonds (C-H) is important in the development of synthetically useful reactions, owing to the proximity-induced reactivity and selectivity that is enabled by coordinating functional groups. Palladium-catalysed non-directed C-H activation could potentially enable further useful reactions, because it can reach more distant sites and be applied to substrates that do not contain appropriate directing groups; however, its development has faced substantial challenges associated with the lack of sufficiently active palladium catalysts. Currently used palladium catalysts are reactive only with electron-rich arenes, unless an excess of arene is used, which limits synthetic applications. Here we report a 2-pyridone ligand that binds to palladium and accelerates non-directed C-H functionalization with arene as the limiting reagent. This protocol is compatible with a broad range of aromatic substrates and we demonstrate direct functionalization of advanced synthetic intermediates, drug molecules and natural products that cannot be used in excessive quantities. We also developed C-H olefination and carboxylation protocols, demonstrating the applicability of our methodology to other transformations. The site selectivity in these transformations is governed by a combination of steric and electronic effects, with the pyridone ligand enhancing the influence of sterics on the selectivity, thus providing complementary selectivity to directed C-H functionalization.
Multi walled carbon nanotubes supported N-heterocyclic carbene-cobalt (II) as a novel, efficient and inexpensive catalyst for the Mizoroki-Heck reaction
Hajipour, Abdol R.,Khorsandi, Zahra
, p. 1 - 4 (2016/01/26)
In this paper, an N-heterocyclic carbene-cobalt complex (NHC-Co2+) was immobilized onto the surface of multi-walled carbon nanotubes (MWCNTs) via direct grafting amination approach for the first time. The resultant composite (Co - NHC@MWCNTs) was characterized by FT-IR, TGA, XRD, ICP-OES, FE-SEM, TEM and CHN analyses. It was demonstrated that Co-NHC@MWCNTs can act as an efficient and inexpensive catalyst for Heck reactions in normal conditions which provided the corresponding products in moderate to good yields. More importantly, this phosphine and palladium-free catalyst can be reused for at least six successive runs without any discernible decrease in its catalytic activity and no remarkable changes were observed in catalyst structure.
N, N-disubstituted benzo-nitrogen heterocycles-2-amine compound and use thereof
-
Paragraph 0089-0092, (2016/10/09)
The invention mainly relates to an N,N-double substituted benzoazacyclo-2-amide compound and an application thereof. The N,N-double substituted benzoazacyclo-2-amide compound is a compound shown as formula I or a salt formed by a medical acid or alkali. The compound provided by the invention has strong inhibition activity on RhoA protease which is tightly related with cardiovascular and cerebrovascular diseases. The compound provided by the invention is hopeful to be developed into a RhoA protease small-molecule inhibitor type cardiovascular and cerebrovascular disease treatment medicine.
Flexible, dicationic imidazolium salts for in situ application in palladium-catalysed Mizoroki–Heck coupling of acrylates under aerobic conditions
Milton, Marilyn Daisy,Garg, Parul
, p. 759 - 766 (2016/09/04)
The synthesis, characterization and in situ catalytic performance of new unsymmetric N,N′-disubstituted imidazolium-based dicationic salts in Mizoroki–Heck coupling of acrylates with aryl bromides under aerobic conditions are described. A series of flexible dicationic salts with varying steric and electronic properties were synthesized in good to excellent yields. All the salts were well characterized using spectroscopic techniques. X-ray diffraction analysis of two salts with the same dicationic backbone and different counter anions shows that the ligand adopts two different conformations which are influenced by the nature of the anion. Thus, the ligand is capable of changing its conformation according to the change in environment due to its flexible nature. All the synthesized imidazolium salts were found to be active in in situ palladium-catalysed Mizoroki–Heck coupling under aerobic conditions. Amongst the salts, the hydroxyl-functionalized imidazolium salt, incorporating the features of both bidentate chelating O,O ligand and carbene, shows the maximum catalytic activity. A variety of aryl and heteroaryl methyl and ethyl cinnamates were synthesized using these imidazolium salts as preligands. In addition, NMR studies confirm in situ generation of normal N-heterocyclic carbenes from the C-2 position of imidazol-2-ylidene ring. The mercury poisoning test was also performed to ascertain the nature of catalytically active palladium species. Aerobic conditions, low catalytic loading (0.5?mol%), shorter reaction times, broad functional group tolerance and good to excellent isolated yields are some of the significant features of the novel catalytic systems described here. Copyright
Highly active, selective, and reusable RuO2/SWCNT catalyst for heck olefination of aryl halides
Gopiraman, Mayakrishnan,Karvembu, Ramasamy,Kim, Ick Soo
, p. 2118 - 2129 (2014/07/21)
Very fine RuO2 nanoparticles (RuO2NPs) with a mean diameter of about 0.9 nm were decorated on single-walled carbon nanotubes (SWCNTs) by a straightforward "dry synthesis" method. TEM images and the Raman spectrum of the resultant material (RuO2/SWCNT) revealed excellent adhesion and homogeneous dispersion of the RuO2NPs on anchoring sites of the SWCNTs. The surface area of RuO2/SWCNT was found to be 416 m2 g-1. The SEM-EDS results showed that the weight percentage of Ru in RuO2/SWCNT was 13.8%. The oxidation state of Ru in RuO2/SWCNT was +4, as confirmed by XPS and XRD analyses. After the complete characterization, a 0.9 mol % loading of RuO 2/SWCNT was used as a nanocatalyst for the Heck olefination of a wide range of aryl halides to yield products in excellent yields with good turnover numbers and turnover frequencies. Less reactive bromo-and chloroarenes were also used for the formation of coupled products in good yields. RuO 2/SWCNT is regioselective, chemoselective, heterogeneous in nature, and reusable. The stability of RuO2/SWCNT was also studied by means of TEM, ICP-MS, SEM-EDS, and XPS analyses.
Molecular design to improve the performance of donor-π acceptor near-IR organic dye-sensitized solar cells
Hao, Yan,Yang, Xichuan,Zhou, Meizhen,Cong, Jiayan,Wang, Xiuna,Hagfeldt, Anders,Sun, Licheng
scheme or table, p. 1601 - 1605 (2012/03/08)
Near-dye experience: Long, flexible carbon chains in the lateral anchoring groups of the donor part of a donor-π acceptor organic dye increase the power conversion efficiency dramatically. This performance enhancement can be ascribed to the prevention of the formation of molecular aggregates on the semiconductor nanoparticles, resulting in a lower recombination rate between transported electrons and I3- ions. A cell based on the new dye, HY113, gives a maximum IPCE value of 93% at 660nm. Copyright
BORON-CONTAINING SMALL MOLECULES
-
Page/Page column 146, (2011/06/16)
This invention relates to 6-substituted benzoxaborole compounds of the following formula and their use for treating bacterial infections.
