6848-13-1Relevant articles and documents
Additive-free selective methylation of secondary amines with formic acid over a Pd/In2O3 catalyst
Benaissa, Idir,Cantat, Thibault,Genre, Caroline,Godou, Timothé,Pinault, Mathieu
, p. 57 - 61 (2022/01/19)
Formic acid is used as the sole carbon and hydrogen source in the methylation of aromatic and aliphatic amines to methylamines. The reaction proceeds via a formylation/transfer hydrogenation pathway over a solid Pd/In2O3 catalyst without the need for any additive.
Utilization of renewable formic acid from lignocellulosic biomass for the selective hydrogenation and/or N-methylation
Zhou, Chao-Zheng,Zhao, Yu-Rou,Tan, Fang-Fang,Guo, Yan-Jun,Li, Yang
, p. 4724 - 4728 (2021/09/06)
Lignocellulosic biomass is one of the most abundant renewable sources in nature. Herein, we have developed the utilization of renewable formic acid from lignocellulosic biomass as a hydrogen source and a carbon source for the selective hydrogenation and further N-methylation of various quinolines and the derivatives, various indoles under mild conditions in high efficiencies. N-methylation of various anilines is also developed. Mechanistic studies indicate that the hydrogenation occurs via a transfer hydrogenation pathway.
Preparation method of N-alkylated derivative of primary amine compound
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Paragraph 0021; 0045, (2021/07/09)
The invention relates to a preparation method of an N-alkylated derivative of a primary amine compound. The method comprises the following steps: uniformly mixing a primary amine compound, an alcohol compound and a catalyst in a reactor, and heating to react for a period of time to generate an N-alkylated substituted tertiary amine compound; wherein the catalyst is a copper-cobalt bimetallic catalyst, and the carrier of the catalyst is Al2O3. According to the method, alcohol is adopted as an alkylating reagent and is low in price and easy to obtain, a byproduct is water, no pollution is caused to the environment, and the overall reaction atom economy is high; the catalyst is simple in preparation method, low in cost, high in reaction activity and good in structural stability; meanwhile, by using the copper-cobalt bimetallic catalyst, the use of strong base additives can be avoided, and the requirement on reaction equipment is low; and the reaction post-treatment is convenient, and the catalyst can be recycled and is environment-friendly.
Additive-freeN-methylation of amines with methanol over supported iridium catalyst
Liu, Xiang,Loh, Teck-Peng,Qiang, Wenwen,Wang, Jing,Ye, Sen,Zhu, Longfei
, p. 3364 - 3375 (2021/06/06)
An efficient and versatile zinc oxide-supported iridium (Ir/ZnO) catalyst was developed to catalyze the additive-freeN-methylation of amines with methanol. Mechanistic studies suggested that the high catalytic reactivity is rooted in the small sizes (1.4 nm) of Ir nanoparticles and the high ratio (93%) of oxidized iridium species (IrOx, Ir3+and Ir4+) on the catalyst. Moreover, the delicate cooperation between the IrOxand ZnO support also promoted its high reactivity. The selectivity of this catalyticN-methylation was controllable between dimethylation and monomethylation by carefully tuning the catalyst loading and reaction solvent. Specifically, neat methanol with high catalyst loading (2 mol% Ir) favored the formation ofN,N-dimethylated amine, while the mesitylene/methanol mixture with low catalyst loading (0.5 mol% Ir) was prone to producing mono-N-methylated amines. An environmentally benign continuous flow system with a recycled mode was also developed for the efficient production ofN-methylated amines. With optimal flow rates and amine concentrations, a variety ofN-methylamines were produced with good to excellent yields in this Ir/ZnO-based flow system, providing a starting point for the clean and efficient production ofN-methylamines with this cost-effective chemical process.
Method for realizing N-alkylation by using alcohols as carbon source under photocatalysis
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Paragraph 0048-0056; 0058, (2021/03/13)
The invention discloses a method for realizing N-alkylation by using alcohols as a carbon source under photocatalysis, and belongs to the technical field of catalytic synthesis. Alcohol, a substrate raw material and a catalyst are placed in a reaction device, ultraviolet and/or visible light irradiation is carried out in an inert atmosphere, after the irradiation is finished, solid-liquid separation is carried out to remove the catalyst, and an N-alkylation product can be obtained through extraction, distillation and purification, wherein the substrate raw material comprises any one of an amine compound, an aromatic nitro compound or an aromatic nitrile compound, the alcohol comprises any one or more of soluble primary alcohols, and the catalyst is metal oxide/titanium dioxide or metal sulfide/titanium dioxide. The method is simple and easy to operate, can be used for efficient photocatalysis one-pot multi-step hydrogenation N-alkylation reaction, and is mild in reaction condition, high in chemical selectivity of N-alkylamine, good in catalyst stability and easy to recycle.
Trialkylammonium salt degradation: Implications for methylation and cross-coupling
Assante, Michele,Baillie, Sharon E.,Juba, Vanessa,Leach, Andrew G.,McKinney, David,Reid, Marc,Washington, Jack B.,Yan, Chunhui
, p. 6949 - 6963 (2021/06/02)
Trialkylammonium (most notably N,N,N-trimethylanilinium) salts are known to display dual reactivity through both the aryl group and the N-methyl groups. These salts have thus been widely applied in cross-coupling, aryl etherification, fluorine radiolabelling, phase-transfer catalysis, supramolecular recognition, polymer design, and (more recently) methylation. However, their application as electrophilic methylating reagents remains somewhat underexplored, and an understanding of their arylation versus methylation reactivities is lacking. This study presents a mechanistic degradation analysis of N,N,N-trimethylanilinium salts and highlights the implications for synthetic applications of this important class of salts. Kinetic degradation studies, in both solid and solution phases, have delivered insights into the physical and chemical parameters affecting anilinium salt stability. 1H NMR kinetic analysis of salt degradation has evidenced thermal degradation to methyl iodide and the parent aniline, consistent with a closed-shell SN2-centred degradative pathway, and methyl iodide being the key reactive species in applied methylation procedures. Furthermore, the effect of halide and non-nucleophilic counterions on salt degradation has been investigated, along with deuterium isotope and solvent effects. New mechanistic insights have enabled the investigation of the use of trimethylanilinium salts in O-methylation and in improved cross-coupling strategies. Finally, detailed computational studies have helped highlight limitations in the current state-of-the-art of solvation modelling of reaction in which the bulk medium undergoes experimentally observable changes over the reaction timecourse. This journal is
Photocatalytic Water-Splitting Coupled with Alkanol Oxidation for Selective N-alkylation Reactions over Carbon Nitride
Xu, Yangsen,Zhang, Zhaofei,Qiu, Chuntian,Chen, Shaoqin,Ling, Xiang,Su, Chenliang
, p. 582 - 589 (2020/12/09)
Photocatalytic water splitting technology (PWST) enables the direct use of water as appealing “liquid hydrogen source” for transfer hydrogenation reactions. Currently, the development of PWST-based transfer hydrogenations is still in an embryonic stage. Previous reports generally centered on the rational utilization of the in situ generated H-source (electrons) for hydrogenations, in which photogenerated holes were quenched by sacrificial reagents. Herein, the fully-utilization of the liquid H-source and holes during water splitting is presented for photo-reductive N-alkylation of nitro-aromatic compounds. In this integrate system, H-species in situ generated from water splitting were designed for nitroarenes reduction to produce amines, while alkanols were oxidized by holes for cascade alkylating of anilines as well as the generated secondary amines. More than 50 examples achieved with a broad range scope validate the universal applicability of this mild and sustainable coupling approach. The synthetic utility of this protocol was further demonstrated by the synthesis of existing pharmaceuticals via selective N-alkylation of amines. This strategy based on the sustainable water splitting technology highlights a significant and promising route for selective synthesis of valuable N-alkylated fine chemicals and pharmaceuticals from nitroarenes and amines with water and alkanols.
Para-Selective C-H Olefination of Aniline Derivatives via Pd/S,O-Ligand Catalysis
Naksomboon, Kananat,Poater, Jordi,Bickelhaupt, F. Matthias,Fernández-Ibá?ez, M. ángeles
supporting information, p. 6719 - 6725 (2019/05/06)
Herein we report a highly para-selective C-H olefination of aniline derivatives by a Pd/S,O-ligand-based catalyst. The reaction proceeds under mild reaction conditions with high efficiency and broad substrate scope, including mono-, di-, and trisubstituted tertiary, secondary, and primary anilines. The S,O-ligand is responsible for the dramatic improvements in substrate scope and the high para-selectivity observed. This methodology is operationally simple, scalable, and can be performed under aerobic conditions.
Nickel(II) Tetraphenylporphyrin as an Efficient Photocatalyst Featuring Visible Light Promoted Dual Redox Activities
Mandal, Tanumoy,Das, Sanju,De Sarkar, Suman
supporting information, p. 3200 - 3209 (2019/05/16)
Nickel(II) tetraphenylporphyrin (NiTPP) is presented as a robust, cost-effective and efficient visible light induced photoredox catalyst. The ground state electrochemical data (CV) and electronic absorption (UV-Vis) spectra reveal the excited state redox potentials for [NiTPP]*/[NiTPP].? and NiTPP].+/[NiTPP]* couples as +1.17 V and ?1.57 V vs SCE respectively. The potential values represent NiTPP as a more potent photocatalyst compare to the well-explored [Ru(bpy)3]2+. The non-precious photocatalyst exhibits excited state redox reactions in dual fashions, i. e., it is capable of undergoing both oxidative as well as reductive quenching pathways. Such versatility of a photocatalyst based on first-row transition metals is very scarce. This unique phenomenon allows one to perform diverse types of redox reactions by employing a single catalyst. Two different sets of chemical reactions have been performed to represent the synthetic utility. The catalyst showed superior efficiency in both carbon-carbon and carbon-heteroatom bond-forming reactions. Thus, we believe that NiTPP is a valuable addition to the photocatalyst library and this study will lead to more practical synthetic applications of earth-abundant-metal-based photoredox catalysts. (Figure presented.).
Air-tolerant direct reductive N-methylation of amines using formic acid via simple inorganic base catalysis
Huang, Yan,Deng, Wei,Lin, Bo-Lin
supporting information, (2019/05/29)
The construction of N-methyl amine moieties is an important reaction that has found numerous applications. Development of new methylation agents that are more environmentally benign than classical agents, such as iodomethane and methyl sulfate, is still highly desirable. Herein, we report a convenient protocol for direct reductive N-methylation of amines using formic acid as the methylation agent via simple inorganic base catalysis. The present protocol operates under transition-metal-free and air-tolerant conditions. Both the catalyst, K2HPO4, and the reductant, polymethylhydrosiloxane (PMHS), are cheap and easily separable from the crude reaction product mixture. Mechanistic investigations suggest that the reaction occur through the formation of an acetal intermediate followed by the C–N bond formation.
