Catalytic methylation of aromatic amines with formic acid as the unique carbon and hydrogen source

Savourey, Solène; Lefèvre, Guillaume; Berthet, Jean‐Claude; Cantat, Thibault

doi:10.1039/c4cc05908e

Cited by 95 publications

(54 citation statements)

References 19 publications

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“…Surprisingly, the corresponding dimethylated anilines were produced with nearly complete conversion and excellent selectivity (88-92%) (see ESI † Supplementary Table S9, Products 7`a-7`h), which is similar to the reported activities of homogenous catalysts with the use of a strong acid additive. 1,3,[9][10][11][12][13][14] This unexpected conversion of anilines into N,N-dimethylanilines indicated the catalytic superiority of the heterogeneous Pd 47 Ag 53 nano-alloy.…”

Section: Resultsmentioning

confidence: 99%

“…From this perspective, there have been various attempts at N-methylation by using a C 1 -building block source (CO 2 , formic acid) and/or a reductant (H 2 , silanes and boranes) with organometallic catalysts, including rhodium, ruthenium and zinc complexes. 1,3,[9][10][11][12][13][14] However, these homogenous catalysts require challenging synthesis processes with an elaborately designed ligand complex, which is difficult to separate and recycle from the products. 15 Furthermore, additives such as organic acids are needed for good performance, and high pressure and/or temperature are required.…”

Section: Introductionmentioning

confidence: 99%

“…Cantat et al have used FA for an amine methylation reaction with a homogeneous Ru(COD)(methylallyl) 2 catalyst and two additives. 10 Recently, Beller's group has reported aniline methylation via FA and hydrosilane with homogenous [Pt] Karstedt's catalyst and toxic organophosphorus ligand. 17 For heterogeneous catalysts, Shimizu et al 18 have previously reported secondary amine methylation using a Pt-based heterogeneous catalyst under CO 2 and H 2 gas-phase conditions, but the drawbacks of that system were its rather harsh conditions, such as high temperature (over 200°C), long reaction time (24 h) and high pressure (50 bar).…”

Section: Introductionmentioning

confidence: 99%

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Heterogeneous PdAg alloy catalyst for selective methylation of aromatic amines with formic acid under an additive-free and solvothermal one-pot condition

2015

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The methylation of amines for the synthesis of methylamines and dimethylamines as platform chemicals has been attempted mostly by homogeneous catalysts with acid additives. However, there are scarcely any reports on heterogeneous catalytic methylation reactions except for a routine approach under high temperature and high pressure of CO 2 and H 2 gases for extended reaction times. Here we report a heterogeneously catalyzed selective methylation of aromatic amines using reactive and nontoxic formic acid as the only source for the construction of methyl groups, under ambient pressure in an additive-free one-pot reaction condition. Equal proportions of Pd and Ag in the PdAg/Fe 3 O 4 /N-rGO catalyst deliver highly selective amine methylation without aromatic ring hydrogenation, as the strained Pd in the alloy is combined with the graphene-derived support, preventing nanoparticle agglomeration and the action of magnetite as a promoter. Both N-methylation and N,N-dimethylation of various substituted aromatic amines were performed with complete conversion and excellent 90-97% selectivity by controlling the reaction times in the range of 10-24 h at 140°C without unwanted aromatic ring hydrogenation. Furthermore, the developed bimetallic catalyst provided high yields (88-91%) of methylation with CO 2 +H 2 gas under high pressure, which are as good as the results of homogenous catalysts with an acid additive. To the best of our knowledge, our use of this environmentally friendly methodology is the first time that this durable heterogeneous catalyst has readily performed highly selective methylation at ambient pressure, which is attractive for industrial applications.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Heterogeneous PdAg alloy catalyst for selective methylation of aromatic amines with formic acid under an additive-free and solvothermal one-pot condition

2015

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“…Cantat et al. first, and Kim et al . reported the N ‐methylation of amines applying FA as a unique carbon and hydrogen source catalyzed by a Ru/Triphos [Triphos=1,1,1‐tris(diphenylphosphinomethyl)ethane] complex or a heterogeneous PdAg alloy catalyst, respectively.…”

Section: Introductionmentioning

confidence: 95%

Efficient and Selective N‐Methylation of Nitroarenes under Mild Reaction Conditions

Pedrajas

Sorribes

Guillamón

et al. 2017

Chemistry A European J

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Herein, we report a straightforward protocol for the preparation of N,N-dimethylated amines from readily available nitro starting materials using formic acid as a renewable C source and silanes as reducing agents. This tandem process is efficiently accomplished in the presence of a cubane-type Mo PtS catalyst. For the preparation of the novel [Mo Pt(PPh )S Cl (dmen) ] (3 ) (dmen: N,N'-dimethylethylenediamine) compound we have followed a [3+1] building block strategy starting from the trinuclear [Mo S Cl (dmen) ] (1 ) and Pt(PPh ) (2) complexes. The heterobimetallic 3 cation preserves the main structural features of its 1 cluster precursor. Interestingly, this catalytic protocol operates at room temperature with high chemoselectivity when the 3 catalyst co-exists with its trinuclear 1 precursor. N-heterocyclic arenes, double bonds, ketones, cyanides and ester functional groups are well retained after N-methylation of the corresponding functionalized nitroarenes. In addition, benzylic-type as well as aliphatic nitro compounds can also be methylated following this protocol.

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“…[3] In addition, industrial production of methyl amines still depends on the reductive amination using toxic formaldehyde (Eschweiler-Clarke methylation). Recently, reductive methylation of amine with CO 2 , [5][6] dimethyl carbonate, [7] or formic acid [8] using reducing agents such as silanes or boranes has been presented for the production of N-methylamines under milder conditions, however, availability and energy requirements for the reducing reagents, as well as the E factor caused by the by-products still remain an issue. Recently, reductive methylation of amine with CO 2 , [5][6] dimethyl carbonate, [7] or formic acid [8] using reducing agents such as silanes or boranes has been presented for the production of N-methylamines under milder conditions, however, availability and energy requirements for the reducing reagents, as well as the E factor caused by the by-products still remain an issue.…”

mentioning

confidence: 99%

Efficient Cobalt‐Catalyzed Methylation of Amines Using Methanol

et al. 2017

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The methylation of amines using methanol is a promising route to synthesize N-methylamines, and the development of cheap and efficient catalytic system for this reaction is of great significance. Herein, we reported a cobalt (Co)based catalytic system, which was in situ formed from commercially available Co precursor and a tetradentate phosphine ligand P(CH 2 CH 2 PPh 2 ) 3 combined with K 3 PO 4 . This catalystic system was very effective for the selective production of dimethylated products from aliphatic amines and monomethylated ones from aromatic amines. The reaction mechanism was further investigated by control and isotope labelling experiments.

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Catalytic methylation of aromatic amines with formic acid as the unique carbon and hydrogen source

Abstract: A novel methodology is presented for the direct methylation of amines, using formic acid as a unique source of carbon and hydrogen. Based on ruthenium(II) catalysts, the formation of the N-CH3 group proceeds via an efficient formylation/transfer hydrogenation pathway.

Cited by 95 publications

References 19 publications

Heterogeneous PdAg alloy catalyst for selective methylation of aromatic amines with formic acid under an additive-free and solvothermal one-pot condition

Heterogeneous PdAg alloy catalyst for selective methylation of aromatic amines with formic acid under an additive-free and solvothermal one-pot condition

Efficient and Selective N‐Methylation of Nitroarenes under Mild Reaction Conditions

Efficient Cobalt‐Catalyzed Methylation of Amines Using Methanol

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