Amination of Alcohols Catalyzed by Copper‐Aluminium Hydrotalcite: A Green Synthesis of Amines

Likhar, Pravin R.; Arundhathi, R.; Kantam, M. Lakshmi; Parvathaneni, Sai Prathima

doi:10.1002/ejoc.200900628

Cited by 126 publications

(64 citation statements)

References 54 publications

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“…To promote the N‐alkylation using ROH, metal‐based catalyses have been developed. These reactions mainly use benzylic‐type and saturated alcohols with catalytic Ru,3 Ir,4 Cu,5a–e Ni,5f and Ag5g,h species. In addition, Lewis acidic metals6 and Pd7 catalysts are also competent mediators of N‐alkylation with benzylic‐type secondary alcohols and allylic alcohols.…”

Section: Methodsmentioning

confidence: 99%

Selective N‐Alkylation of Amines with Alcohols by Using Non‐Metal‐Based Acid–Base Cooperative Catalysis

Oishi

Saitō

2011

Chemistry A European J

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Higher amines are widely used in both the bulk and fine chemical industry for the synthesis of fundamental materials, such as additives, dyes and agrochemicals.[1] Therefore, the development of a selective N-alkylation method that is cost effective, salt free and environmentally benign is of considerable interest. Indeed, reactions involving the N-alkylation of amines with alcohols [2] (R À OH) in place of R À X, where X denotes halide, tosylate, mesylate, or triflate, [1d,e] are well documented. To promote the N-alkylation using RÀOH, metal-based catalyses have been developed. These reactions mainly use benzylic-type and saturated alcohols with catalytic Ru, [3] Ir, [4] Cu, [5a-e] Ni, [5f] and Ag [5g,h] species. In addition, Lewis acidic metals [6] and Pd [7] catalysts are also competent mediators of N-alkylation with benzylic-type secondary alcohols and allylic alcohols. Herein, we report a novel and straightforward method for the N-alkylation with R À OH (18, 28 and 38) using non-metal-based [8a] catalysis promoted by 1,3,5-triazo-2,4,6-triphosphorine-2,2,4,4,6,6-hexachloride [9] (TAPC). This new reaction involves substitution (S N ) at the alcohols sp 3 carbon atom bearing the hydroxyl group (Scheme 1), [8b] by which selective N-mono-and dialkylation were successfully achieved.Treatment of aniline (1 a, 2 equiv) with benzyl alcohol (2 a, 1 equiv) in the presence of TAPC (5 mol % with respect to 2 a) at 160 8C for 12 h in 1,2,4-trimethylbenzene (1,2,4-TMB) under Ar using a sealed reactor, [10] followed by column chromatography on silica gel, gave mono-alkylated amine 3 aa in 92 % yield (Scheme 2, Table 1, entry 1).[11] The tertiary amine resulting from N-dialkylation was obtained in about 7 % yield, as determined by GC-MS and 1 H NMR spectroscopy. Formation of benzyl chloride and dibenzyl ether was found to be negligible [12] by GC-MS analysis. In the absence of solvent, the yield of 3 aa decreased to 75 % (entry 1). Addition of water (0.3 and 2.0 equiv with respect to 2 a) to the solute at 25 8C prior to reaction initiation did not prevent the reaction from proceeding at 160 8C (3 aa was recovered in 98 and 90 %, respectively). Finally, a change in the ratio of 1 a/2 a from 2:1 to 1:2.5 resulted exclusively in N-dialkylation, giving 4 aa in 80 % yield (entry 2). [13] Control reactions were performed to probe the involvement of Brønsted acid catalysts that might be generated in [a] Dr.

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Section: Methodsmentioning

confidence: 99%

Selective N‐Alkylation of Amines with Alcohols by Using Non‐Metal‐Based Acid–Base Cooperative Catalysis

Oishi

Saitō

2011

Chemistry A European J

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“…对比 Likhar 和 Shi 等 [17,18,20] 的报道, Xu 等的研究更为细致和透彻, 相关分步反应和机理研究不仅经过实验证实, 也有其他相关研究领域大量的文献支持(见上下文) [2,4,,13～16,23～25,27,28] . 因此, 他们提出的机理也是有关有…”

Section: 提法究其本质是一样的都认为反应经过形成金属氢化物[Mh]或[mh 2 ]的机理进行(Scheme 3)unclassified

Recent Advances of Transition Metal-Catalyzed Aerobic Dehydrative Reactions of Alcohols and Amines and Related Researches

Xu¹,

Li²

2013

Chin. J. Org. Chem.

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In comparison with other methods, transition metal-catalyzed dehydrative N-alkylation of amines and amides with alcohols, commonly known as the borrowing hydrogen or hydrogen autotransfer reactions and the methodology, is a comparatively green and atom-economic method for the synthesis of the useful amine and amide derivatives. Recently, transition metal-catalyzed aerobic dehydrative N-alkylation method has also attracted much attention, for the reactions can be readily conducted under milder and simpler conditions by using the more stable metal catalysts under the air atmosphere. In this review, we summarize the recent advances of transition metal-catalyzed aerobic dehydrative C-N and C＝N bond forming reactions of alcohols with amines and amides for the synthesis of the amine and amide derivatives and imines, as well as those of the related aerobic dehydrative C-alkylation reactions. Mechanisms of the above reactions are also discussed.

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“…Several catalytic systems for the amination of alcohols have been studied under homogeneous conditions based on platinum [6] [PtCl 2 (PhCN) 2 ], rhodium [7] [RhH(PPh 3 ) 4 ], ruthenium [8] [Ru 3 (CO) 12 ], and iridium [9] {[IrCl(COD)] 2 } catalysts. Although these catalysts are active for the reaction, they are significantly expensive and non-recoverable [10]. Compared with homogeneous catalysts, heterogeneous catalysts have some advantages with the easy recovery possible being the most important one [11].…”

Section: Introductionmentioning

confidence: 99%

Research on the N-alkylation of morpholine with alcohols catalyzed by CuO–NiO/γ–Al2O3

Chen

Luo

Qian

et al. 2011

Reac Kinet Mech Cat

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The N-alkylation of morpholine with alcohols in gas-solid phase was investigated in a fixed-bed reactor over CuO-NiO/c-Al 2 O 3 catalyst prepared by the impregnation method. The N-methylation of morpholine with methanol gave a 95.3% conversion with a 93.8% selectivity of N-methylmorpholine under the optimum reaction condition, and the corresponding apparent activation energy is 46.20 kJ mol -1 . The present catalytic system is also applicable to other low-carbon primary alcohols. However, secondary alcohols enjoy relatively low product selectivity for the resulting ketone is a poorer electrophile than an aldehyde. For cyclohexanol, the low conversion and selectivity are mainly due to steric effects. The catalyst shows a high catalytic activity without obvious fluctuation during a long period of 120 h.

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Amination of Alcohols Catalyzed by Copper‐Aluminium Hydrotalcite: A Green Synthesis of Amines

Cited by 126 publications

References 54 publications

Selective N‐Alkylation of Amines with Alcohols by Using Non‐Metal‐Based Acid–Base Cooperative Catalysis

Selective N‐Alkylation of Amines with Alcohols by Using Non‐Metal‐Based Acid–Base Cooperative Catalysis

Recent Advances of Transition Metal-Catalyzed Aerobic Dehydrative Reactions of Alcohols and Amines and Related Researches

Research on the N-alkylation of morpholine with alcohols catalyzed by CuO–NiO/γ–Al2O3

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