14435-88-2Relevant academic research and scientific papers
Highly regioselective assembly of Di- or trisubstituted pyridines from arynes, isocyanides, and 3-bromo- or 3-acetoxypropynes
Sha, Feng,Shen, Hui,Wu, Xin-Yan
, p. 2537 - 2540 (2013)
A facile synthetic method for the preparation of di- and trisubstituted pyridines with high regioselectivity through an intramolecular pericyclization strategy is disclosed. The multicomponent reaction of isocyanides, arynes, and 3-bromopropyne affords disubstituted pyridines in good yields. In contrast, the use of 3-acetoxypropyne results in the formation of trisubstituted pyridines through intramolecular pericyclization of an in situ formed azatriene. In this way, desirable pyridines can be constructed in a one-pot manner. The preparation of di- or trisubstituted pyridines with high regioselectivity through the multicomponent reaction of isocyanides, arynes, and 3-bromo or 3-acetoxypropyne is described. The pyridine ring is constructed through intramolecular pericyclization of an in situ generated azatriene intermediate. The pyridine products are assembled effectively in a one-pot manner under mild conditions. Copyright
Syntheses of Pyrroles, Pyridines, and Ketonitriles via Catalytic Carbopalladation of Dinitriles
Qi, Linjun,Li, Renhao,Yao, Xinrong,Zhen, Qianqian,Ye, Pengqing,Shao, Yinlin,Chen, Jiuxi
, p. 1097 - 1108 (2020/01/22)
The first example of the Pd-catalyzed addition of organoboron reagents to dinitriles, as an efficient means of preparing 2,5-diarylpyrroles and 2,6-diarylpyridines, has been discussed here. Furthermore, the highly selective carbopalladation of dinitriles with organoboron reagents to give long-chain ketonitriles has been developed as well. Based on the broad scope of substrates, excellent functional group tolerance, and use of commercially available substrates, the Pd-catalyzed addition reaction of arylboronic acid and dinitriles is expected to be significant in future synthetic procedures.
Palladium (II) Complexes Containing 2-Phenylpyridine Derivatives: Synthesis, Molecular Structures, and Catalytic Activity for Suzuki–Miyaura Cross-Coupling Reactions
Adamson, A.,Alhaddad, M. R.,Arshad, M. N.,Asiri, A. M.,Budiman, Y. P.,Mkhalid, I.,Muhammad, R.
, p. 466 - 475 (2020/07/31)
The preparation and characterization of a series of new 2-phenylpyridine derivative ligands consisting of 2-(R) pyridine (R = mesityl (L1), 2,6-dimethylphenyl (L2), o-tolyl (L3), m-tolyl (L4), p-tolyl (L5), o-methoxyphenyl (L6), and p-methoxyphenyl (L7)) and their Pd complexes [PdCl2L2] (L1–L7) is investigated using a combination of X-ray diffraction spectroscopy, GC-MS, and NMR. The crystal structures show that the Pd complexes adopt a square planar geometry, and the monodentate ligand is coordinated through the N donor of the pyridine ring to the Pd atom. The catalytic activities of the synthesized complexes are investigated. The square planar Pd complex trans-[(2-mesitylpy)2PdCl2)] shows a high efficiency in promoting Suzuki-Miyaura cross coupling in an aqueous solvent under aerobic conditions.
Synthesis of Asymmetrical 2,6-Diarylpyridines from Linear α,β,γ,δ-Unsaturated Ketones by Addition of Ammonium Formate Followed by Annulation
Chen, Rener,Gao, Yejun,Ma, Yongmin
, p. 3875 - 3882 (2019/10/11)
A simple and efficient method has been established for the synthesis of asymmetrical 2,6-diarylpyridines by cyclization of α,β,γ,δ-unsaturated ketones with ammonium formate under air atmosphere. The reaction is metal-free and operationally convenient from readily available starting materials. Thirty-three examples have been presented, most of which show good yields.
Pd-Catalyzed Decarboxylation and Dual C(sp3)-H Functionalization Protocols for the Synthesis of 2,4-Diarylpyridines
Gujjarappa, Raghuram,Vodnala, Nagaraju,Kumar, Mohan,Malakar, Chandi C.
, p. 5005 - 5020 (2019/04/25)
The Pd-catalyzed decarboxylation and dual C(sp3)-H bond functionalization approaches have been described for the preparation of symmetrical and unsymmetrical 2,4-diarylpyridines. The developed transformations were realized using nonactivated aromatic ketones and amino acids as C-N sources. The efficacy of the catalyst and reagent combination drives the transformation toward the formation of desired products with high yields and selectivity. The described reaction conditions have seduced the self-reaction of phenylalanine via [2 + 2 + 2] cycloaddition and minimized the formation of 3,5-phenylpyridine as a side product, whereas using glycine as a C-N source, the corresponding 2,6-diarylpyridines were formed as minor products.
Copper-Catalyzed Site-Selective Oxidative C?C Bond Cleavage of Simple Ketones for the Synthesis of Anilides and Paracetamol
Vodnala, Nagaraju,Gujjarappa, Raghuram,Hazra, Chinmoy K.,Kaldhi, Dhananjaya,Kabi, Arup. K.,Beifuss, Uwe,Malakar, Chandi C.
supporting information, p. 135 - 145 (2018/12/05)
A copper-catalyzed approach for the N-acylation of anilines with acetone and acetophenones via C?C bond cleavage is described. Under the developed conditions both CHCl3 and CH2Cl2 were identified as potential C1-source to promote the transformation. The reaction features a site selective C?C bond cleavage to install the amide moieties with high functional-group compatibility and wide substrate scope. The developed method avoids the use of sensitive and narcotic agents. The method also represents an excellent complement to the previous protocols with lower E-factor (13.91 mg/1 mg) than current industrially used method (E-factor 17.54 mg/1 mg). The developed approach has also been extended for the effective preparation of pyridine derivatives and paracetamol in gram scale. The course of the reaction was monitored by 1H NMR as a preliminary investigation of the reaction mechanism. (Figure presented.).
C6-Selective Direct Arylation of 2-Phenylpyridine via an Activated N-methylpyridinium Salt: A Combined Experimental and Theoretical Study
Yin, Changzhen,Zhong, Kangbao,Li, Wenjing,Yang, Xiao,Sun, Rui,Zhang, Chunchun,Zheng, Xueli,Yuan, Maolin,Li, Ruixiang,Lan, Yu,Fu, Haiyan,Chen, Hua
supporting information, p. 3990 - 3998 (2018/09/12)
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.).
Method for double carbon-hydrogen activation and arylation of pyridine compounds
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Paragraph 0040; 0041; 0042; 0043; 0044-0048, (2017/04/21)
The invention discloses a method for double carbon-hydrogen activation and arylation of pyridine compounds, and belongs to the field of methodology of organic synthesis. The method comprises the following steps: mixing a palladium source, a phosphine ligand, a copper salt or an oxide of copper, an alkali and aryl halide, placing the mixture in a nitrogen gas environment, then adding an additive, 4-substituted pyridine and a solvent, and carrying out a heating reaction, to obtain a C2-site and C6-site double aryl substituted pyridine compounds through a carbon-hydrogen activation mechanism, wherein a substituent group of 4-substituted pyridine is any one of hydrogen, alkyl and aryl. The method has the advantages of wide application range, simple operation steps, no need of pre-activation of a pyridine ring, and no need of introduction of a guiding group, and extremely high atomic economy and practicability.
Direct C-H Functionalization of Pyridine via a Transient Activator Strategy: Synthesis of 2,6-Diarylpyridines
Zeng, Yang,Zhang, Chunchun,Yin, Changzhen,Sun, Maoshen,Fu, Haiyan,Zheng, Xueli,Yuan, Maolin,Li, Ruixiang,Chen, Hua
supporting information, p. 1970 - 1973 (2017/04/27)
A Pd-catalyzed highly selective direct diarylation of pyridines has been developed using a transient activator strategy. Both (MeO)2SO2 and Cu2O are required for this transformation. The in situ generated N-methylpyridinium salt can be arylated at both 2- and 6-positions under the cooperative Pd/Cu catalysis. A subsequent N-demethylation then gives the 2,6-diarylpyridines. This protocol provides a novel synthetic route for the symmetric 2,6-diarylpyridines.
One-pot synthesis of symmetrical 2,6-diarylpyridines via palladium/copper-catalyzed sequential decarboxylative and direct C-H arylation
Ma, Zhiyong,Liu, Hailong,Zhang, Chunchun,Zheng, Xueli,Yuan, Maolian,Fu, Haiyan,Li, Ruixiang,Chen, Hua
supporting information, p. 1143 - 1148 (2015/04/22)
A palladium(II)/copper oxide (Cu2O)-catalyzed one-pot decarboxylative and direct C-H arylation of 2-picolinic acid with aryl bromides has been developed. Various aryl bromides have been shown to be efficient coupling partners in the presence of dimethyl sulfate, furnishing symmetrical 2,6-diarylpyridines in moderate to good yields.
