1539-39-5Relevant articles and documents
On-line reaction monitoring and mechanistic studies by mass spectrometry: Negishi cross-coupling, hydrogenolysis, and reductive amination
Yan, Xin,Sokol, Ewa,Li, Xin,Li, Guangtao,Xu, Shiqing,Cooks, R. Graham
, p. 5931 - 5935 (2014)
Reaction monitoring using inductive ESI mass spectrometry allows chemical reactions to be tracked in real time, including air- and moisture-sensitive as well as heterogeneous reactions. Highly concentrated solutions can also be monitored for long periods without emitter clogging. Sheath gas assists in nebulization and a sample splitter reduces the delay time and minimizes contamination of the instrument. Short-lived intermediates (ca. 5 s) were observed in Pd/C-catalyzed hydrogenolysis, and several intermediates were seen in Negishi cross-coupling reactions. Fast and simple: A reaction monitoring system based on inductive ESI mass spectrometry provides a fast and simple way to monitor chemical reactions, including air-/moisture-sensitive reactions, continuously. It also provides information on solution-phase organic reaction mechanisms as shown by the observation of short-lived intermediates in Pd/C-catalyzed hydrogenolysis and several intermediates in Negishi cross-coupling reactions.
Solvent-Dependent Formations of Supramolecular Isomers and a Single-Crystal to Single-Crystal Transformation from a Cyclic Dimer Complex to a One-Dimensional Coordination Polymer
Habata, Yoichi,Hongu, Haruka,Ikeda, Mari,Kuwahara, Shunsuke,Lee, Eunji,Temma, Honoka,Toya, Masato
, p. 3284 - 3292 (2020)
Solvent-dependent supramolecular isomers of a tripodal ligand incorporating two para-pyridylmethyl arms, N-naphthylmetyl-N,N-bis(4-pyridylmethyl)amine (L), are reported. A combination of L and copper(II) hexafluoroacetylacetonate, Cu(hfac)2, in methanol afforded a cyclic dimer complex [Cu2(L)2(hfac)4]·CH3OH (1). In chloroform/methanol, the same reaction furnished an infinite one-dimensional (1D) complex {[Cu2(L)2(hfac)4]·2CHCl3}n (2). When the cyclic dimer 1 was immersed in chloroform/ether, its transformation to the 1D coordination polymer 2 was observed in an single-crystal to single-crystal manner. In silver(I) triflate complexations, three supramolecular isomers (3-5) were isolated. In chloroform/methanol, a multichannel-type three-dimensional (3D) coordination polymer {[Ag(L)](CF3SO3)·0.5CHCl3}n (3) was isolated. In isomer 3, the Ag atom link L ligands alternately to form a helix, and these are linked by Ag-Ag contacts to generate an etb topology. In acetonitrile/methanol, a multichannel-type 3D coordination polymer {[Ag(L)](CF3SO3)·CH3CN}n (4) was isolated. In isomer 4, six Ag atoms and six L ligands form an Ag6L6 hexagonal unit, and these are linked via Ag-Ag contacts, resulting in a pcu-h topology. In toluene/methanol/acetonitrile, a cross-linked ladder-type coordination polymer {[Ag4(L)4(CF3SO3)2](CF3SO3)2·3(toluene)}n (5) was obtained. The isomer 5 is composed of two types of ladders crossed showing a new topology. Considering the formation of the (π-π)-(Ag-Ag)-(π-π) unit in 3-5, it is suggested that the anion-solvent interaction could be a major reason.
Cobalt complex, preparation method thereof, and application thereof in selective catalysis of transfer hydrogenation reaction of cyano group
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Paragraph 0165-0167; 0169, (2018/05/07)
The invention discloses a cobalt complex, a preparation method thereof, and an application thereof in the selective catalysis of a transfer hydrogenation reaction of a cyano group. The structural formula of the cobalt complex is represented by formula I. The cobalt complex is prepared through a reaction of a cobalt salt and an NNP ligand or a PNP ligand under the protection of an inert atmosphere;and the chemical formula of the cobalt salt is CoX12, wherein X1 represents halogen, a sulfate radical, a perchlorate radical, a hexafluorophosphate radical, a hexafluoroantimonate radical, a tetrafluoroborate radical, a trifluoromethanesulfonate radical or a tetra(pentafluorophenyl)borate radical. The cobalt complex can be used in the selective catalysis of the transfer hydrogenation reaction ofthe cyano group to obtain a primary amine compound, a secondary amine compound and a tertiary amine compound, the primary amine compound, the secondary amine compound and the tertiary amine compoundare important intermediates in a series of subsequent functionalizing reactions, and the cobalt complex has a very high catalysis activity, and has great research values and a great application prospect.
Hydrogenation of heteroaromatic nitriles and aromatic dinitriles by heterogeneous or homogeneous ruthenium catalysts derived from [Ru3(CO)12]
García, Juventino J.,Pérez-Lezama, Nora,Arévalo, Alma
, p. 55 - 58 (2017/05/05)
The use of the complex [Ru3(CO)12] (1) as a catalyst precursor (0.1?mol%) at 200?°C, 60?psi of H2, along with triphenylphosphine (TPP) generated ruthenium nanoparticles (Ru-Nps); this occurred in the presence of pyridine-nitriles leading to a variety of hydrogenation (secondary amine, imine, or imidazole) products, depending of the pyridine-nitrile used, under similar reaction conditions. This relates to relatively good to modest yields, determined by the substituents in the corresponding pyridine. In sharp contrast, the use of aromatic dinitriles did not generate Ru-Nps at 140?°C, 150?psi of H2 and TPP, but allowed the homogeneous catalytic hydrogenation of the 1,4- and 1,3-dicyanobenzenes, to yield the corresponding CN-substituted secondary amine or imine. The main products were characterized by different analytical methods and spectroscopic techniques.
Nano-sized La0.5Ca0.5CoO3-mediated reduction by nabh4 of aryl nitriles to bis-(benzyl) amines
Bavandi, Hossein,Shiri, Ali,Tavakkoli, Haman
, p. 3330 - 3334 (2017/05/29)
Nano-sized La0.5Ca0.5CoO3 perovskite, which was produced via the sol-gel method, was an efficient heterogeneous catalyst in combination with NaBH4 for the rapid chemoselective reduction of aryl nitriles to bis-(benzyl)amines at 40°C in good to excellent yields. The physico-chemical properties of the catalyst were characterized by means of differential thermal analysis (DTA), thermogravimetric analysis (TGA), X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDX) and particle size distributions images. The results show that nanoparticles have regular shapes with well-defined crystal faces with an average size of 30 nm.
Mild and Selective Cobalt-Catalyzed Chemodivergent Transfer Hydrogenation of Nitriles
Shao, Zhihui,Fu, Shaomin,Wei, Mufeng,Zhou, Shaolin,Liu, Qiang
supporting information, p. 14653 - 14657 (2016/11/23)
Herein, we describe a selective cobalt-catalyzed chemodivergent transfer hydrogenation of nitriles to synthesize primary, secondary, and tertiary amines. The solvent effect plays a key role for the selectivity control. The general applicability of this procedure was highlighted by the synthesis of more than 70 amine products bearing various functional groups in high chemoselectivity. Moreover, this mild system achieved >2000 TONs (turnover numbers) for the transfer hydrogenation of nitriles.
Selective hydrogenation of nitriles to secondary amines catalyzed by a pyridyl-functionalized and alkenyl-tethered NHC-Ru(II) complex
Saha, Sayantani,Kaur, Mandeep,Singh, Kuldeep,Bera, Jitendra K.
, p. 87 - 94 (2016/06/09)
A set of Co(III) and Ru(II) compounds are synthesized bearing pyridyl-functionalized and alkenyl-tethered N-heterocyclic carbene (NHC) ligand (L1). [CoIII(L1)3](PF6)3 (1) was synthesized by the reaction of [L1H]PF6, Co(OAc)2.4H2O, K2CO3 in tetrahydrofuran (THF) under refluxing condition. [RuIIL1(η6-p-cymene)Cl]PF6 (2) was synthesized via transmetallation method. For both compounds, the NHC ligand chelates the metal through carbene carbon and pyridyl nitrogen whereas the butenyl unit remains free. Compound 2 hydrogenates organic nitriles efficiently providing selectively secondary amines. In the presence of external amines, unsymmetrical secondary amines are also obtained.
Effective conversion of heteroaromatic ketones into primary amines via hydrogenation of intermediate ketoximes
Baucom, Kyle D.,Guram, Anil S.,Borths, Christopher J.
, p. 201 - 204 (2015/03/03)
A process to access heteroaromatic primary amines from the corresponding heteroaromatic ketones has been developed. A broad range of previously reported methods to convert ketones to primary amines was examined on heterocyclic ketones without success, including Leuckart-Wallach conditions, borane reductions, and transition-metal-catalyzed hydrogenations. Unique among the catalysts examined, Raney cobalt produced the desired primary heterocyclic amine. Raney cobalt hydrogenation of structurally varied heterocyclic ketoximes was demonstrated to form primary amines in good selectivity under mild conditions, and the products are easily isolated in high yield. Additionally, this is the first report of a systematic evaluation of the capabilities of Raney cobalt as an oxime hydrogenation catalyst.
Selective synthesis of secondary amines from nitriles using Pt nanowires as a catalyst
Lu, Shuanglong,Wang, Jiaqing,Cao, Xueqin,Li, Xinming,Gu, Hongwei
supporting information, p. 3512 - 3515 (2014/03/21)
A new one-pot method has been developed for the selective synthesis of secondary amines via reductive amination of the corresponding nitriles using Pt nanowires as a catalyst. This method allows for the synthesis of both unsymmetrical and symmetrical secondary amines in excellent yields (up to 95%) in the presence or absence of additional amines, respectively. Furthermore, the reaction proceeds under mild conditions and is environmentally benign.
Heterogeneously catalyzed self-condensation of primary amines to secondary amines by supported copper catalysts
Kim, Insu,Itagaki, Shintaro,Jin, Xiongjie,Yamaguchi, Kazuya,Mizuno, Noritaka
, p. 2397 - 2403 (2013/09/02)
Self-condensation of primary amines to symmetrically substituted secondary amines could efficiently be promoted by an inexpensive supported copper catalyst, Cu/Al2O3, easily prepared by the reduction of the hydroxide precursor, Cu(OH)x/Al2O3. Various kinds of structurally diverse primary amines including benzylamine, picolylamine, and aliphatic amine derivatives could selectively be converted into the corresponding secondary amines in moderate to excellent yields without any cocatalysts such as bases and stabilizing ligands in 1 atm of Ar or H 2. The reactions in H2 showed higher selectivities to desired secondary amines than those in Ar. The roles of H2 are the promotion of hydrogenation of N-alkylimines and the stabilization of active Cu(0) species. In addition, in the presence of Cu/Al2O3, unsymmetrically substituted secondary amines could efficiently be synthesized by N-alkylation of primary amines with alcohols and reductive amination of aldehydes. The observed catalysis was truly heterogeneous, and the retrieved Cu/Al2O3 catalyst could be reused for self-condensation without a significant loss of its catalytic performance. The reaction mechanism involving dehydrogenation of primary amines and condensation to N-alkylimines followed by hydrogenation, the so-called "borrowing hydrogen pathway", has been proposed. The Royal Society of Chemistry 2013.
