4329-81-1Relevant articles and documents
Effect of the ancillary ligand in N-heterocyclic carbene iridium(III) catalyzed N-alkylation of amines with alcohols
Feng, Xinshu,Huang, Ming
, (2021/06/21)
A series of air-stable N-heterocyclic carbene (NHC) Ir(III) complexes (Ir1-6), bearing various combinations of chlorine, pyridine and NHC ligands, were assayed for the N-alkylation of amines with alcohols. It was found that Ir3, with two monodentate 1,3-bis-methyl-imidazolylidene (IMe) ligands, emerged as the most active complex. A large variety of amines and primary alcohols were efficiently converted into mono-N-alkylated amines in 53–96% yields. As a special highlight, for the challenging MeOH, selective N-monomethylation could be achieved using KOH as a base under an air atmosphere. Moreover, this catalytic system was successfully applied to the gram-scale synthesis of some valuable compounds.
Synthesis of an Fe-Pd bimetallic catalyst for: N -alkylation of amines with alcohols via a hydrogen auto-transfer methodology
Wu, Peng-Yu,Lu, Guo-Ping,Cai, Chun
, p. 396 - 404 (2021/01/28)
Hydrogen auto-transfer (HAT) or borrowing hydrogen (BH) methodology which combines dehydrogenation, intermediate reaction and hydrogenation, is recognized as an excellent strategy for one-pot synthesis from an economic and environmental point of view. Although much effort has been made on the development of catalysts for HAT reactions, harsh conditions, external base or large amounts of noble metals are still required in most reported catalysis systems, and thus the exploration of a highly efficient and recyclable heterogeneous catalyst remains meaningful. In this work, a novel bimetallic catalyst, Fe10Pd1/NC500 derived from bimetallic MOF NH2-MIL-101(Fe10Pd1), has been prepared, and the catalyst exhibits superior catalytic performance for the N-alkylation of amines with alcohols via a hydrogen auto-transfer methodology. High yields of the desired products were achieved at 120 °C with an alcohol/amine molar ratio of 2?:?1 and required no external additive or solvent. A distinct enhancement in catalytic performance is observed when compared with monometallic catalysts, which can be ascribed to the "synergistic effects"inside the bimetallic alloys. The N-doped carbon support has been revealed to provide the necessary basicity which avoids the requirement of an external base. Moreover, a wide substrate range and remarkable reusability have been shown by Fe10Pd1/NC500, and this work highlights new possibilities for bimetallic catalysts applied in sustainable chemistry.
Convenient and Reusable Manganese-Based Nanocatalyst for Amination of Alcohols
Subaramanian, Murugan,Ramar, Palmurukan M.,Sivakumar, Ganesan,Kadam, Ravishankar G.,Petr, Martin,Zboril, Radek,Gawande, Manoj B.,Balaraman, Ekambaram
, p. 4334 - 4341 (2021/08/25)
The development of new sustainable nanocatalytic systems for green chemical synthesis is a growing area in chemical science. Herein, a reusable heterogeneous N-doped graphene-based manganese nanocatalyst (Mn@NrGO) for selective N-alkylation of amines with alcohols is described. Mechanistic studies illustrate that the catalytic reaction follows a domino dehydrogenation-condensation-hydrogenation sequence of alcohols and amines with the formation of water as the sole by-product. The scope of the reaction is extended to the synthesis of pharmaceutically important N-alkylated amine intermediates. The heterogeneous nature of the catalyst made it easy to separate for long-term performance, and the recycling study revealed that the catalyst was robust and retained its activity after several recycling experiments.
Ruthenium(ii) complexes with N-heterocyclic carbene-phosphine ligands for theN-alkylation of amines with alcohols
Huang, Ming,Li, Yinwu,Lan, Xiao-Bing,Liu, Jiahao,Zhao, Cunyuan,Liu, Yan,Ke, Zhuofeng
supporting information, p. 3451 - 3461 (2021/05/03)
Metal hydride complexes are key intermediates forN-alkylation of amines with alcohols by the borrowing hydrogen/hydrogen autotransfer (BH/HA) strategy. Reactivity tuning of metal hydride complexes could adjust the dehydrogenation of alcohols and the hydrogenation of imines. Herein we report ruthenium(ii) complexes with hetero-bidentate N-heterocyclic carbene (NHC)-phosphine ligands, which realize smart pathway selection in theN-alkylated reactionviareactivity tuning of [Ru-H] species by hetero-bidentate ligands. In particular, complex6cbwith a phenyl wingtip group and BArF?counter anion, is shown to be one of the most efficient pre-catalysts for this transformation (temperature is as low as 70 °C, neat conditions and catalyst loading is as low as 0.25 mol%). A large variety of (hetero)aromatic amines and primary alcohols were efficiently converted into mono-N-alkylated amines in good to excellent isolated yields. Notably, aliphatic amines, challenging methanol and diamines could also be transformed into the desired products. Detailed control experiments and density functional theory (DFT) calculations provide insights to understand the mechanism and the smart pathway selectionvia[Ru-H] species in this process.
Ligand compound for copper catalyzed aryl halide coupling reaction, catalytic system and coupling reaction
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Paragraph 0086-0091; 0094, (2021/05/29)
The invention provides a ligand compound capable of being used for copper catalyzed aryl halide coupling reaction, the ligand compound is a three-class compound containing a 2-(substituted or non-substituted) aminopyridine nitrogen-oxygen group, and the invention also provides a catalytic system for the aryl halide coupling reaction. Thecatalytic system comprises a copper catalyst, a compound containing a 2-(substituted or non-substituted) aminopyridine nitrogen-oxygen group adopted as a ligand, alkali and a solvent, and meanwhile, the invention also provides a system for the aryl halide coupling reaction adopting the catalyst system. The compound containing the 2-(substituted or non-substituted) aminopyridine nitrogen oxygen group can be used as the ligand for the copper catalyzed aryl chloride coupling reaction, and the ligand is stable under a strong alkaline condition and can well maintain catalytic activity when being used for the copper-catalyzed aryl chloride coupling reaction. In addition, the copper catalyst adopting the compound as the ligand can particularly effectively promote coupling of copper catalyzed aryl chloride and various nucleophilic reagents which are difficult to generate under conventional conditions, C-N, C-O and C-S bonds are generated, and numerous useful small molecule compounds are synthesized. Therefore, the aryl halide coupling reaction has a very good large-scale application prospect by adopting the copper catalysis system of the ligand.
Nickel(II)-NΛNΛO Pincer Type Complex-Catalyzed N-alkylation of Amines with Alcohols via the Hydrogen Autotransfer Reaction
Balamurugan, Gunasekaran,Ramesh, Rengan,Malecki, Jan Grzegorz
, p. 7125 - 7135 (2020/06/08)
A highly sustainable catalytic protocol for the coupling of alcohols and amines for selective monoalkylated amines using Ni(II)-NΛNΛO pincer type complexes through the borrowing hydrogen methodology is described. An array of Ni(II) catalysts (1-3) was synthesized and characterized by various spectral and analytical methods. Furthermore, the distorted square planar geometry of the complexes (1 and 2) was substantiated with single crystal X-ray diffraction study. The inexpensive nickel-based catalytic methodology displays a broad substrate scope for the N-alkylation of aromatic and heteroaromatic amines using a diverse range of primary alcohols with excellent yields up to 97%. The present approach is environmentally benign, which liberates water as the sole byproduct. A short synthesis of drug intermediates such as mepyramine and chloropyramine illustrates the utility of the present protocol.
Ruthenium(II) Complexes of Heteroditopic N-Heterocyclic Carbene Ligands: Efficient Catalysts for C-N Bond Formation via a Hydrogen-Borrowing Strategy under Solvent-Free Conditions
Donthireddy,Mathoor Illam, Praseetha,Rit, Arnab
supporting information, p. 1835 - 1847 (2020/01/31)
Both imidazol-2-ylidene (ImNHC) and 1,2,3-triazol-5-ylidene (tzNHC) have evolved to be elite groups of N-heterocyclic carbene (NHC) ligands for homogeneous catalysis. To develop efficient ruthenium(II)-based catalysts incorporating these ligands for C-N bond-forming reactions via hydrogen-borrowing methodology, we utilized chelating ligands integrated with ImNHC and mesoionic tzNHC donors connected via a CH2 spacer with a diverse triazole backbone. The synthesized ruthenium(II) complexes 3 are found to be highly efficient for C-N bond formation across a wide range of primary amine and alcohol substrates under solvent-free conditions, and among all of the complexes studied here, catalyst 3a with a mesityl substituent displayed maximum activity. To our delight, catalyst 3a is also effective for the selective mono-N-methylation of various anilines utilizing methanol as a coupling partner, known to be relatively more difficult than other alcohols. Furthermore, complex 3a also delivers various substituted quinolines successfully via the reaction of 2-aminobenzyl alcohol with several secondary alcohols. Importantly, catalyst 3a exhibited the highest activity among the reported ruthenium(II) complexes for both the N-benzylation of aniline [achieving a turnover number (TON) of 50000] and the realization of quinoline 8a by reacting 2-aminobenzyl alcohol with 2-phenylethanol (attaining a TON of 30000).
Zinc-Catalyzed N-Alkylation of Aromatic Amines with Alcohols: A Ligand-Free Approach
Sankar, Velayudham,Kathiresan, Murugavel,Sivakumar, Bitragunta,Mannathan, Subramaniyan
supporting information, p. 4409 - 4414 (2020/09/01)
An efficient zinc-catalyzed N-alkylation reaction of aromatic amines was achieved using aliphatic, aromatic, and heteroaromatic alcohols as the alkylating reagent. A variety of aniline derivatives, including heteroaromatic amines, underwent the N-alkylation reaction and furnished the corresponding monoalkylated products in good to excellent yields. The application of the reaction is also further demonstrated by the synthesis of a 2-phenylquinoline derivative from acetophenone and 2-aminobenzyl alcohol. Deuterium labeling experiments show that the reaction proceeds via a borrowing hydrogen process. (Figure presented.).
Bidentate geometry-constrained iminopyridyl nickel-catalyzed synthesis of amines or imines via borrowing hydrogen or dehydrogenative condensation
Jiang, Yong,Hu, Miao,Sun, Nan,Hu, Baoxiang,Shen, Zhenlu,Hu, Xinquan,Jin, Liqun
supporting information, (2020/11/27)
The efficient Ni-catalyzed N-alkylation of various anilines with alcohols via borrowing hydrogen is reported using a bidentate geometry-constrained iminopyridyl nickel complex as the catalyst. Substituted benzylic alcohols and short/long chain aliphatic alcohols could be applied as the alkylation sources to couple with aromatic and heteroaromatic amines to give a diverse set of N-alkylation outcomes in moderate to excellent yields. The nickel catalytic system was also suitable for aliphatic amines, selectively delivering the corresponding imines via an acceptorless dehydrogenative condensation strategy.
Solvent-Free N-Alkylation and Dehydrogenative Coupling Catalyzed by a Highly Active Pincer-Nickel Complex
Arora, Vinay,Dutta, Moumita,Das, Kanu,Das, Babulal,Srivastava, Hemant Kumar,Srivastava, Hemant Kumar,Kumar, Akshai,Kumar, Akshai
, p. 2162 - 2176 (2020/06/05)
The synthesis and characterization of a pincer-nickel complex of the type (iPr2NNN)NiCl2(CH3CN) is reported here. We have demonstrated the utility of this pincer-nickel complex (0.02 and 0.002 mol %) for the catalytic N-alkylation of amines using various alcohols. Under solvent-free conditions, while the highest yield (ca. 90%) was obtained for the alkylation of 2-aminopyridine with naphthyl-1-methanol, excellent turnovers (34000 TONs) were observed for the alkylation of 2-aminopyridine with 4-methoxybenzyl alcohol. To demonstrate the synthetic utility of these systems, high-yield reactions (up to 98%) have been probed for representative substrates with a higher loading of the pincer-nickel catalyst (4 mol %). DFT studies indicate that while β-hydride elimination is the RDS for alcohol dehydrogenation, the N-alkylated product can be formed either via hydrogenation with a rate-determining σ-bond metathesis or by alcoholysis that has imine insertion as the RDS. All of the corresponding resting states have been observed by HRMS (ESI) analysis. The labeling experiments are also complementary to DFT studies and show evidence for the involvement of the benzylic C-H bond in the RDS with a kCHH/kCHD value of about 2.5. This method has been applied to accomplish efficient (2000 TONs) dehydrogenative coupling leading to various benzimidazoles.
