68049-21-8Relevant academic research and scientific papers
Nanosilica-anchored Pd(II)-Schiff base complex as efficient heterogeneous catalyst for activation of aryl halides in Suzuki–Miyaura cross-coupling reaction in water
Gogoi, Nibedita,Bora, Utpal,Borah, Geetika,Gogoi, Pradip K.
, (2017)
A nanosilica (derived from rice husk)-anchored Pd(II)–Schiff base complex has been synthesized and characterized. This immobilized complex has been found to be a very effective and recyclable heterogeneous catalyst for the Suzuki–Miyaura cross-coupling reaction of various aryl halides with arylboronic acid in aqueous medium under mild conditions. The products were identified using 1H NMR and mass spectral studies. This complex can be easily filtered out from the reaction medium and reused up to six times without significant loss of catalytic activity. Since the reaction proceeds under mild conditions in aqueous medium as well as the catalyst being recyclable, it provides an environmentally benign alternative route to the existing protocols for the Suzuki–Miyaura reaction.
Palladium-catalysed electrophilic aromatic C-H fluorination
Yamamoto, Kumiko,Li, Jiakun,Garber, Jeffrey A. O.,Rolfes, Julian D.,Boursalian, Gregory B.,Borghs, Jannik C.,Genicot, Christophe,Jacq, Jér?me,Van Gastel, Maurice,Neese, Frank,Ritter, Tobias
, p. 511 - 514 (2018/03/02)
Aryl fluorides are widely used in the pharmaceutical and agrochemical industries, and recent advances have enabled their synthesis through the conversion of various functional groups. However, there is a lack of general methods for direct aromatic carbon-hydrogen (C-H) fluorination. Conventional methods require the use of either strong fluorinating reagents, which are often unselective and difficult to handle, such as elemental fluorine, or less reactive reagents that attack only the most activated arenes, which reduces the substrate scope. A method for the direct fluorination of aromatic C-H bonds could facilitate access to fluorinated derivatives of functional molecules that would otherwise be difficult to produce. For example, drug candidates with improved properties, such as increased metabolic stability or better blood-brain-barrier penetration, may become available. Here we describe an approach to catalysis and the resulting development of an undirected, palladium-catalysed method for aromatic C-H fluorination using mild electrophilic fluorinating reagents. The reaction involves a mode of catalysis that is unusual in aromatic C-H functionalization because no organometallic intermediate is formed; instead, a reactive transition-metal-fluoride electrophile is generated catalytically for the fluorination of arenes that do not otherwise react with mild fluorinating reagents. The scope and functional-group tolerance of this reaction could provide access to functional fluorinated molecules in pharmaceutical and agrochemical development that would otherwise not be readily accessible.
An immobilized symmetrical bis-(NHC) palladium complex as a highly efficient and recyclable Suzuki-Miyaura catalyst in aerobic aqueous media
Begum, Tahshina,Mondal, Manoj,Borpuzari, Manash Protim,Kar, Rahul,Kalita, Golap,Gogoi, Pradip K.,Bora, Utpal
supporting information, p. 539 - 546 (2017/01/10)
A bis-N-heterocyclic carbene (NHC) functionalized with chloropropyltriethoxysilane over silica was used to synthesize a well-defined immobilized palladium complex. This complex is a suitable and easily retrievable catalyst for Suzuki-Miyaura cross-coupling reactions under mild aqueous conditions. Excellent yields and conversions were obtained with low palladium loadings (down to 0.03 mol% Pd). The catalyst can be reused up to six cycles without the loss of its activity. The catalytic role of the NHC complex of palladium during coupling between bromobenzene and phenylboronic acid was investigated theoretically. The oxidative addition step is predicted to be endothermic in agreement with the experimental conditions.
DIRECT PALLADIUM-CATALYZED AROMATIC FLUORINATION
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Paragraph 00209; 00210, (2017/09/27)
Provided herein are palladium complexes comprising a ligand of Formula (Α') and a ligand of Formula (B), wherein R1-R18 are as defined herein. The palladium complexes are useful in methods of fluorinating aryl and heteroaryl substrates. Further provided are compositions and kits comprising the palladium complexes.
Insight into Copper Catalysis: In Situ Formed Nano Cu2O in Suzuki-Miyaura Cross-Coupling of Aryl/Indolyl Boronates
Ranjani, Ganapathy,Nagarajan, Rajagopal
supporting information, p. 3974 - 3977 (2017/08/14)
A ligand-free copper catalyzed Suzuki-Miyaura coupling of 3,5-diiodopyridine with aryl and indole boronates has been explored in good to excellent yields. In situ generation of nano-Cu2O from CuCl2 under the reaction conditions has been discovered for the first time. The generality of the reaction was further demonstrated by the arylation of 5-iodopyrimidine, iodopyridines, iodobenzenes, and diiodobenzenes and resulted in good to moderate yields. Moreover, bisindole alkaloid Scalaridine A has been successfully synthesized in 60% overall yield.
Synthesis of zwitterionic palladium complexes and their application as catalysts in cross-coupling reactions of aryl, heteroaryl and benzyl bromides with organoboron reagents in neat water
Ramakrishna,Dastagiri Reddy
, p. 8598 - 8610 (2017/07/12)
N-(3-Chloro-2-quinoxalinyl)-N′-arylimidazolium salts (aryl = 2,6-diisopropylphenyl [HL1Cl]Cl, aryl = mesityl [HL2Cl]Cl) have been synthesized by treating 2,3-dichloroquinoxaline with the corresponding N′-arylimidazole in neat water. Facile reactions of these imidazolium salts with Pd(PPh3)4 and Pd2(dba)3/PPh3 (dba = dibenzyledene acetone) at 50 °C have afforded zwitterionic palladium(ii) complexes [Pd(HL1)(PPh3)Cl2] (I) and [Pd(HL2)(PPh3)Cl2] (II) in excellent yields. I and II have been tested for their ability to catalyze Suzuki-Miyaura cross coupling (SMC) reactions in neat water/K2CO3 and are found to be highly active for carrying out these reactions between aryl bromides and organoboron reagents. Furthermore, the scope of the catalyst I was also examined by employing (hetero)aryl bromides, hydrophilic aryl bromides, benzyl bromides and various organoboron reagents. More than 80 aryl/benzyl bromide-arylboronic acid combinations were screened in neat water/K2CO3 and it was found that I was a versatile catalyst, which produced biaryls/diarylmethanes in excellent yields. A TON of 82 000 was achieved by using I. Studies on the mechanism have also been carried out to investigate the involvement of carbene complexes in the catalytic path. Poison tests and a two-phase test were also conducted and the results are reported.
An improved Suzuki–Miyaura cross-coupling reaction with the aid of in situ generated PdNPs: evidence for enhancing effect with biphasic system
Mahanta, Abhijit,Mondal, Manoj,Thakur, Ashim Jyoti,Bora, Utpal
supporting information, p. 3091 - 3095 (2016/07/06)
We present here an improved Suzuki–Miyaura cross-coupling in WERSA (Water Extract of Rice Straw Ash). We found that, although the reaction can be run in neat water, use of alcoholic co-solvent dramatically enhances the yield and generates in situ PdNPs during the reaction. The PdNPs were characterized by TEM and powder XRD analysis. The rice straw ash was characterized by EDX, Flame photometry, and Ion-Exchange chromatography to reveal a broad range of active metal species. The chemical analysis reports of ash showed the presence of oxides of K, Na, and Ca, which probably in the presence of water produces the corresponding hydroxides responsible for the basicity.
Synthesis and evaluation of antitubercular activity of fluorinated 5-aryl-4-(hetero)aryl substituted pyrimidines
Verbitskiy, Egor V.,Baskakova, Svetlana A.,Kravchenko, Marionella A.,Skornyakov, Sergey N.,Rusinov, Gennady L.,Chupakhin, Oleg N.,Charushin, Valery N.
, p. 3771 - 3780 (2016/07/20)
Various 5-(fluoroaryl)-4-(hetero)aryl substituted pyrimidines have been synthesized based on the Suzuki cross-coupling and nucleophilic aromatic substitution of hydrogen (SNH) reactions starting from commercially available 5-bromopyr
Palladium-Schiff-base-silica framework as a robust and recyclable catalyst for Suzuki-Miyaura cross-coupling in aqueous media
Begum, Tahshina,Mondal, Manoj,Gogoi, Pradip K.,Bora, Utpal
, p. 38085 - 38092 (2015/06/25)
A silica supported palladium catalyst, Pd@imine-SiO2 was prepared by immobilizing Pd(OAc)2 onto silica gel through coordination of imine, generated via Schiff-base condensation between 3-aminopropyltriethoxysilane (APTES) functionalized silica gel and salicylaldehyde. The prepared catalyst was characterized by FT-IR, BET surface area measurements, XRD, SEM-EDX, EDS-mapping and ICP-AES analysis. The imine-based catalyst exhibited excellent activity in the Suzuki-Miyaura cross-coupling reactions of aryl bromides with arylboronic acids in iPrOH/H2O (1:1) at room temperature. The reaction proceeds under mild reaction conditions and the catalyst is recyclable, thus offering an environmentally benign alternative to the existing protocols.
A general and highly efficient method for the construction of aryl-substituted N-heteroarenes
Liu, Chun,Han, Na,Song, Xiaoxiao,Qiu, Jieshan
supporting information; experimental part, p. 5548 - 5551 (2011/02/19)
A general, simple and highly efficient method has been developed for the Pd(OAc)2-catalyzed ligand-free and aerobic Suzuki reaction of N-heteroaryl halides, which is strongly dependent on the molecular structure of solvent. A general, simple and highly efficient method has been developed for the Pd(OAc)2-catalyzed ligand-free and aerobic Suzuki reaction of N-heteroaryl halides including 2-pyridyl bromides, 3-pyridyl bromides, 3-quinolyl bromides, 5-pyrimidyl bromides and 2-pyrazyl chloride, which is strongly dependent on the molecular structure of solvent.
