68254-64-8Relevant academic research and scientific papers
Triple helicate constructed by covalent bondings: Crystal structure and effective synthesis based on propeller-like substructures
Tominaga, Masahide,Masu, Hyuma,Katagiri, Kosuke,Kato, Takako,Azumaya, Isao
, p. 3785 - 3787 (2005)
(Chemical Equation Presented) A triple helicate, having a macrocyclic aromatic amide structure, was synthesized in high yield because of a preorganized component of the tertiary benzenetrianilide moieties in a propeller-like syn conformation at both ends. The helicity was derived from tilted T-shaped aromatic-aromatic (CH-π) interactions between each of the N-phenyl rings.
Highly Active Ni Nanoparticles on N-doped Mesoporous Carbon with Tunable Selectivity for the One-Pot Transfer Hydroalkylation of Nitroarenes with EtOH in the Absence of H2
Tao, Yuewen,Nie, Yunqing,Hu, Haitao,Wang, Ke,Chen, Yi,Nie, Renfeng,Wang, Jianshe,Lu, Tianliang,Zhang, Yongsheng,Xu, Chunbao Charles
, p. 4243 - 4250 (2021/08/20)
Cost-effective and environmentally friendly conversion of nitroarenes into value-added products is desirable but still challenging. In this work, highly dispersed Ni nanoparticles (NPs) supported on N-doped mesoporous carbon (Ni/NC-x) were synthesized via novel ion exchange-pyrolysis strategy. Their catalytic performance was investigated for one-pot transfer hydroalkylation of nitrobenzene (NB) with EtOH in absence of H2. Interestingly, the catalytic performance could be easily manipulated by tuning the morphology and electronic state of Ni NPs via varying the pyrolysis temperature. It was found that the Ni/NC-650 achieved 100 % nitrobenzene conversion and approx. 90 % selectivity of N,N-diethyl aniline at 240 °C for 5 h, more active than those of homogeneous catalysts or supported Ni catalysts prepared by impregnation (Ni/NC-650-IM, Ni/SiO2). This can be ascribed to the higher dispersion and better reducibility as well as richer surface basicity of the catalyst. More interestingly, the Ni/NC-650 catalyst achieved complete conversion of various nitroarenes, yielding imines, secondary amines, or tertiary amines selectively by simply controlling the reaction temperature at 180, 200 and 240 °C, respectively. The one-pot hydrogen-free process with non-noble metal catalysts, as demonstrated in this work, shows great promise for selective conversion of nitroarenes with ethanol to various anilines at industrial scale, from an economic, environmental, and safety viewpoint.
Continuous-Flow Amide and Ester Reductions Using Neat Borane Dimethylsulfide Complex
?tv?s, Sándor B.,Kappe, C. Oliver
, p. 1800 - 1807 (2020/02/27)
Reductions of amides and esters are of critical importance in synthetic chemistry, and there are numerous protocols for executing these transformations employing traditional batch conditions. Notably, strategies based on flow chemistry, especially for amide reductions, are much less explored. Herein, a simple process was developed in which neat borane dimethylsulfide complex (BH3?DMS) was used to reduce various esters and amides under continuous-flow conditions. Taking advantage of the solvent-free nature of the commercially available borane reagent, high substrate concentrations were realized, allowing outstanding productivity and a significant reduction in E-factors. In addition, with carefully optimized short residence times, the corresponding alcohols and amines were obtained in high selectivity and high yields. The synthetic utility of the inexpensive and easily implemented flow protocol was further corroborated by multigram-scale syntheses of pharmaceutically relevant products. Owing to its beneficial features, including low solvent and reducing agent consumption, high selectivity, simplicity, and inherent scalability, the present process demonstrates fewer environmental concerns than most typical batch reductions using metal hydrides as reducing agents.
Mild catalytic deoxygenation of amides promoted by thorium metallocene
Eisen, Moris S.,Saha, Sayantani
, p. 12835 - 12841 (2020/10/05)
The organoactinide-catalyzed (Cp*2ThMe2) hydroborated reduction of a wide range of tertiary, secondary, and primary amides to the corresponding amines/amine-borane adductsviadeoxygenation of the amides is reported herein. The catalytic reactions proceed under mild conditions with low catalyst loading and pinacolborane (HBpin) concentration in a selective fashion. Cp*2ThMe2is capable of efficiently catalysing the gram-scale reaction without a drop in efficiency. The amine-borane adducts are successfully converted into free amine products in high conversions, which increases the usefulness of this catalytic system. A plausible mechanism is proposed based on detailed kinetics, stoichiometric, and deuterium labeling studies.
Direct N-Alkylation/Fluoroalkylation of Amines Using Carboxylic Acids via Transition-Metal-Free Catalysis
Lu, Chunlei,Qiu, Zetian,Xuan, Maojie,Huang, Yan,Lou, Yongjia,Zhu, Yiling,Shen, Hao,Lin, Bo-Lin
supporting information, p. 4151 - 4158 (2020/08/21)
A scalable protocol of direct N-mono/di-alkyl/fluoroalkylation of primary/secondary amines has been constructed with various carboxylic acids as coupling agents under the catalysis of a simple air-tolerant inorganic salt, K3PO4. Advantageous features include 100 examples, 10 drugs and drug-like amines, fluorinated complex tertiary amines, gram-scale synthesis and isotope-labelling amine, thus demonstrating the potential applicability in industry of this methodology. The involvement of relatively less reactive silicon-hydride compared with the traditional reactive metal-hydride or boron-hydride species required to reduce the amide intermediates presumably contributes to the remarkable functional group compatibility. (Figure presented.).
B(C6F5)3-Catalyzed Deoxygenative Reduction of Amides to Amines with Ammonia Borane
Pan, Yixiao,Luo, Zhenli,Han, Jiahong,Xu, Xin,Chen, Changjun,Zhao, Haoqiang,Xu, Lijin,Fan, Qinghua,Xiao, Jianliang
supporting information, p. 2301 - 2308 (2019/01/30)
The first B(C6F5)3-catalyzed deoxygenative reduction of amides into the corresponding amines with readily accessible and stable ammonia borane (AB) as a reducing agent under mild reaction conditions is reported. This metal-free protocol provides facile access to a wide range of structurally diverse amine products in good to excellent yields, and various functional groups including those that are reduction-sensitive were well tolerated. This new method is also applicable to chiral amide substrates without erosion of the enantiomeric purity. The role of BF3 ? OEt2 co-catalyst in this reaction is to activate the amide carbonyl group via the in situ formation of an amide-boron adduct. (Figure presented.).
Ru-Catalyzed Deoxygenative Transfer Hydrogenation of Amides to Amines with Formic Acid/Triethylamine
Pan, Yixiao,Luo, Zhenli,Xu, Xin,Zhao, Haoqiang,Han, Jiahong,Xu, Lijin,Fan, Qinghua,Xiao, Jianliang
supporting information, p. 3800 - 3806 (2019/07/12)
A ruthenium(II)-catalyzed deoxygenative transfer hydrogenation of amides to amines using HCO2H/NEt3 as the reducing agent is reported for the first time. The catalyst system consisting of [Ru(2-methylallyl)2(COD)], 1,1,1-tris(diphenylphosphinomethyl) ethane (triphos) and Bis(trifluoromethane sulfonimide) (HNTf2) performed well for deoxygenative reduction of various secondary and tertiary amides into the corresponding amines in high yields with excellent selectivities, and exhibits high tolerance toward functional groups including those that are reduction-sensitive. The choice of hydrogen source and acid co-catalyst is critical for catalysis. Mechanistic studies suggest that the reductive amination of the in situ generated alcohol and amine via borrowing hydrogen is the dominant pathway. (Figure presented.).
Alkylation of Aromatic Amines with Trialkyl Amines Catalyzed by a Defined Iridium Complex with a 2-Hydroxypyridylmethylene Fragment
Deng, Danfeng,Hu, Bowen,Zhang, Ziyu,Mo, Shengkai,Yang, Min,Chen, Dafa
, p. 2218 - 2226 (2019/05/21)
Six Cp?Ir complexes containing NN-bitentate chelate ligands [Cp?IrCl(C5H4CH2C5H3OH)][Cl] (1), [Cp?IrCl(C5H4CH2C5H3O)] (2), [Cp?IrCl(C5H4C5H3OH)] [Cl] (3), [Cp?IrCl(C5H4CH2C5H4)][Cl] (4), [Cp?IrCl(CH3OC5H3CH2C5H3OCH3)][Cl] (5), and [Cp?IrCl(CH3OC5H3CH2C5H3OH)][Cl] (6) were synthesized and characterized. Complex 1 could be transformed to 2 when reacted with NaOtBu or NEt3 via -OH deprotonation. These six complexes were tested as catalysts for mono-N-alkylation of amines with trialkyl amines, and complex 1 exhibited highest activity. The coupling reactions proceed under air condition, with 1 mol % catalyst loading without extra base in methanol at 120 °C and can be further accelerated by adding NR3·HCl.
Deoxygenative Hydrogenation of Amides Catalyzed by a Well-Defined Iridium Pincer Complex
Yuan, Ming-Lei,Xie, Jian-Hua,Zhu, Shou-Fei,Zhou, Qi-Lin
, p. 3665 - 3669 (2016/07/06)
The iridium-catalyzed highly chemoselective hydrogenation of amides to amines has been developed. Using a well-defined iridium catalyst bearing a P(O)C(O)P pincer ligand combined with B(C6F5)3, the C-O cleavage products are formed under mild reaction conditions. The reaction provides a new method for the preparation of amines from amides in good yield with high selectivity.
Boron Lewis Acid Promoted Ruthenium-Catalyzed Hydrogenation of Amides: An Efficient Approach to Secondary Amines
Yuan, Ming-Lei,Xie, Jian-Hua,Zhou, Qi-Lin
, p. 3036 - 3040 (2016/10/11)
The hydrogenation of amides to amines has been developed by using the catalyst [Ru(H)2(CO)(Triphos)] (Triphos=1,1,1-tri(diphenylphosphinomethyl)ethane) and catalytic boron Lewis acids such as B(C6F5)3 or BF3?Et2O as additives. The reaction provides an efficient method for the preparation of secondary amines from amides in good yields with high selectivity.
