N-Methylation of amines and nitroarenes with methanol using heterogeneous platinum catalysts

Jamil, Md. A. R.; Touchy, Abeda S.; Rashed, Md. Nurnobi; Ting, Kah Wei; Siddiki, S. M. A. Hakim; Toyao, Takashi; Maeno, Zen; Shimizu, Ken‐ichi

doi:10.1016/j.jcat.2019.01.027

Cited by 57 publications

(40 citation statements)

References 60 publications

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“…Later, Watanabe and co‐workers [23] used RuCl 3 .nH 2 O/P(OBu) 3 catalytic system for N ‐methylation of amines with methanol at 180 °C, but the substrate scope is very narrow. After their seminal work, many groups have extended the state of selective N ‐methylation of amines or nitroarenes with methanol in presence of noble‐ [3a–e,h,l‐q,s,u‐z,aa, ac‐ae,24] and non‐noble metals ‐ [3f,g,i–k,r,t, ab, af‐ag] . Regarding ruthenium catalysis, to date only five homogeneous catalytic systems are reported ( Figure 1 ) .…”

Section: Introductionmentioning

confidence: 99%

Simple RuCl₃‐catalyzed N‐Methylation of Amines and Transfer Hydrogenation of Nitroarenes using Methanol

et al. 2021

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Methanol is a potential hydrogen source and C1 synthon, which finds interesting applications in both chemical synthesis and energy technologies. The effective utilization of this simple alcohol in organic synthesis is of central importance and attracts scientific interest. Herein, we report a clean and cost‐competitive method with the use of methanol as both C1 synthon and H2 source for selective N‐methylation of amines by employing relatively cheap RuCl3.xH2O as a ligand‐free catalyst. This readily available catalyst tolerates various amines comprising electron‐deficient and electron‐donating groups and allows them to transform into corresponding N‐methylated products in moderate to excellent yields. In addition, few marketed pharmaceutical agents (e. g., venlafaxine and imipramine) were also successfully synthesized via late‐stage functionalization from readily available feedstock chemicals, highlighting synthetic value of this advanced N‐methylation reaction. Using this platform, we also attempted tandem reactions with selected nitroarenes to convert them into corresponding N‐methylated amines using MeOH under H2‐free conditions including transfer hydrogenation of nitroarenes‐to‐anilines and prepared drug molecules (e. g., benzocaine and butamben) as well as key pharmaceutical intermediates. We further enable one‐shot selective and green syntheses of 1‐methylbenzimidazole using ortho‐phenylenediamine (OPDA) and methanol as coupling partners.

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Section: Introductionmentioning

confidence: 99%

Simple RuCl₃‐catalyzed N‐Methylation of Amines and Transfer Hydrogenation of Nitroarenes using Methanol

et al. 2021

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“…Hong and co‐workers reported the N ‐monomethylation of aliphatic primary amines with methanol by a homogeneous Ru catalyst, but the reaction needed to be carrioed out under hydrogen atmosphere (4 MPa) [11c] . More recently, Shimizu and coworkers reported the N ‐monomethylation of aliphatic primary amines by heterogeneous Pt/C under hydrogen atmosphere (4 MPa) [17] . All of the catalyst systems (either homogeneous or heterogeneous) reported previously for the N ‐monomethylation of aliphatic primary amines required a hydrogen atmosphere and relatively long reaction time to achieve a high selectivity and high conversion, and had no or limited reverability or reusability.…”

Section: Entry Cat Atmopshere Temperature [°C] Time [H] Conversion[b]...mentioning

confidence: 99%

N‐Monomethylation of Amines with Methanol by Syndiotactic Poly(aminostyrene)‐supported Palladium Nanoparticle Catalyst

et al. 2021

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Palladium nanocatalyst supported on dimethylamino‐functionalized syndiotactic polystyrene (Pd@sPS‐NMe2) showed high activity and selectivity for the N‐monomethylation of various primary amines using methanol as methylation reagent under air. The excellent catalytic performance could be associated with the ultrafine palladium nanoparticles and high amine‐adsorbing capacity of the catalyst. The Pd@sPS‐NMe2 catalyst was highly robust, and could be easily recovered by filtration and reused more than ten times without decrease in activity and selectivity.

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“…It has been reported that the synthesis catalyst [(N,N′-bis(diisopropylphosphino)-2,6diaminopyridine)Mn(CO)3][Br] can obtain 90% separation yields after optimization, but the existence of alkali and molecular sieve with a high chemical equivalence ratio is necessary [37]. The previously reported Pt/C also gave high yields for this reaction, but it also required higher reaction temperatures and reaction times [38]. In summary, to make this series conversion reaction more widely used, the reaction conditions were milder and more sustainable, therefore, the heterogeneous catalysis of different metals was applied to the N-monomethylation of nitroaromatic hydrocarbons with methanol as methylation and hydrogenation source.…”

Section: Introductionmentioning

confidence: 95%

“…One of the other traditional synthetic ways for preparing aromatic amines uses inexpensive and readily available nitroarenes for reductive amination [21][22][23][24]. In these cases, with methanol as an economical and sustainable C1 source in the reaction for methylation and water as the sole byproduct, this method is more attractive and promising from both economic and environmental perspectives [22,[24][25][26][27][28][29]. Moreover, the dehydrogenation performance of methanol is much higher than that of higher alcohols such as ethanol and isopropanol.…”

Section: Introductionmentioning

confidence: 99%

Facile synthesis of novel heterogenous Rh/COF catalyst and its application in tandem selective transfer hydrogenation and mono-methylation of Nitro compounds with Methanol

Liu¹,

Zhang

Wang

et al. 2021

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The development of transition metal heterogeneous catalysts for economical and effective synthesis of N-methylamine, especially for the mono-methylation of amines is still challenging. Herein, two unprecedented Rh-supported COFs heterogeneous catalysts Rh/MelCOF was facile synthesized by Schiff base reaction using melamine as a precursor, and for the first time, it was successfully applied to the effective and high selective tandem reaction of transfer hydrogenation and mono-methylation of nitroaromatic hydrocarbons with methanol as C1 and hydrogenation source, with water as the only by-product. A series of nitroaromatic hydrocarbons, including heterocyclic or sterically hindered derivatives, can be well tolerated and the catalyst could also be reused 4 times without losing significant reactivity. At the same time, the study of the Rh/MelCOF mechanism supports the hydrogen borrowing mechanism and puts forward the reaction pathway of azobenzene as an intermediate, which is better than the hydrogen transfer pathway from N-phenylhydroxylamine to aniline directly. This work not only expands the COF family but also provides an effective way to obtain mono N-methylated amines from nitroaromatic hydrocarbons, as well as the detailed mechanism of Rh/COF catalyzed tandem transfer hydrogenation and mono-methylation of amines.

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N-Methylation of amines and nitroarenes with methanol using heterogeneous platinum catalysts

Cited by 57 publications

References 60 publications

Simple RuCl₃‐catalyzed N‐Methylation of Amines and Transfer Hydrogenation of Nitroarenes using Methanol

Simple RuCl₃‐catalyzed N‐Methylation of Amines and Transfer Hydrogenation of Nitroarenes using Methanol

N‐Monomethylation of Amines with Methanol by Syndiotactic Poly(aminostyrene)‐supported Palladium Nanoparticle Catalyst

Facile synthesis of novel heterogenous Rh/COF catalyst and its application in tandem selective transfer hydrogenation and mono-methylation of Nitro compounds with Methanol

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N-Methylation of amines and nitroarenes with methanol using heterogeneous platinum catalysts

Cited by 57 publications

References 60 publications

Simple RuCl3‐catalyzed N‐Methylation of Amines and Transfer Hydrogenation of Nitroarenes using Methanol

Simple RuCl3‐catalyzed N‐Methylation of Amines and Transfer Hydrogenation of Nitroarenes using Methanol

N‐Monomethylation of Amines with Methanol by Syndiotactic Poly(aminostyrene)‐supported Palladium Nanoparticle Catalyst

Facile synthesis of novel heterogenous Rh/COF catalyst and its application in tandem selective transfer hydrogenation and mono-methylation of Nitro compounds with Methanol

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Simple RuCl₃‐catalyzed N‐Methylation of Amines and Transfer Hydrogenation of Nitroarenes using Methanol

Simple RuCl₃‐catalyzed N‐Methylation of Amines and Transfer Hydrogenation of Nitroarenes using Methanol