- Gas-phase 1H NMR studies of internal rotation activation energies and conformer stabilities of asymmetric N,N-disubstituted formamides and trifluoroacetamides
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Activation parameters and conformational stabilities characterizing the internal rotation about the peptide bond in a series of N,N-asymmetric dialkylformamides (HCONR1R2: R1 = CH3, R2 = propyl, butyl, and isopropyl) and N,N-asymmetric dialkyltrifluoroacetamides (F3CCONR1R2: R1 = CH3, R2 = propyl, butyl, and isopropyl) are determined from temperature-dependent gas-phase 1H NMR spectra. Conformer free energy differences, ΔG0298(syn-anti), in cal mol-1, and activation free energies, ΔG?298, in kcal mol-1 , for the formamides are -83(14)/19.4(0.1) for R2 = propyl, -80(14)719.3(0.1) for R2 = butyl, and -91(13)719.1(0.1) for R2 = isopropyl and for the trifluoroacetamides 178(24) /16.8(0.1) for R2 = propyl, 191(53)716.6(0.1) for R2 = butyl, and 218(29)716.3(0.1) for R2 = isopropyl. The preferred conformer in both the gas and liquid phases has the N-methyl group syn to the carbonyl oxygen in the formamide systems and the N-methyl group anti to the carbonyl oxygen in the trifluoroacetamides. The gas-phase results are compared to liquid-phase values.
- Taha,Neugebauer Crawford,True
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- N-Formylation of Amines with CO2 and H2 by Using NHC–Iridium Coordination Assemblies as Solid Molecular Catalysts
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One of the NHC–iridium coordination assemblies containing 1,5-cyclooctadiene (COD) and iodide ion has been demonstrated as robust, efficient, recyclable solid molecular catalyst for N-formylation of diverse primary and secondary amines with CO2 and H2 under mild reaction conditions. Remarkably, in the case of N,N-dimethylformamide production, even at 0.1 mol % catalyst loading under solvent-free conditions, the solid catalyst can be readily recovered by simply filtration and reused more than 10 runs without noticeable loss of activity.
- Zhang, Yang,Wang, Jiaquan,Zhu, Haibo,Tu, Tao
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- Methanol Promoted Palladium-Catalyzed Amine Formylation with CO2 and H2 by the Formation of HCOOCH3
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The N-formylation reaction of amines is one of the most effective measures to make the best use of CO2, since the formamides have widespread applications in industry. Herein, we performed the N-formylation reaction over Mg?Al layered double hydroxide (Mg?Al LDH) supported Pd catalyst (Pd/LDH) for the first time and studied the relation between the solvent and the mechanism. In this reaction, the methanol can greatly improve the yield of the desired product by forming the HCOOCH3. The catalytic system is effective for various amines including cyclic and alkyl secondary amines. Under the optimized reaction condition, we gained 88.5 %–97.4 % yields of the formamides for various substrates.
- Wang, Yanyan,Chen, Bingfeng,Liu, Shulin,Shen, Xiaojun,Li, Shaopeng,Yang, Youdi,Liu, Huizhen,Han, Buxing
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- Methyl-Selective α-Oxygenation of Tertiary Amines to Formamides by Employing Copper/Moderately Hindered Nitroxyl Radical (DMN-AZADO or 1-Me-AZADO)
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Methyl-selective α-oxygenation of tertiary amines is a highly attractive approach for synthesizing formamides while preserving the amine substrate skeletons. Therefore, the development of efficient catalysts that can advance regioselective α-oxygenation at the N-methyl positions using molecular oxygen (O2) as the terminal oxidant is an important subject. In this study, we successfully developed a highly regioselective and efficient aerobic methyl-selective α-oxygenation of tertiary amines by employing a Cu/nitroxyl radical catalyst system. The use of moderately hindered nitroxyl radicals, such as 1,5-dimethyl-9-azanoradamantane N-oxyl (DMN-AZADO) and 1-methyl-2-azaadamanane N-oxyl (1-Me-AZADO), was very important to promote the oxygenation effectively mainly because these N-oxyls have longer life-times than less hindered N-oxyls. Various types of tertiary N-methylamines were selectively converted to the corresponding formamides. A plausible reaction mechanism is also discussed on the basis of experimental evidence, together with DFT calculations. The high regioselectivity of this catalyst system stems from steric restriction of the amine-N-oxyl interactions.
- Nakai, Satoru,Yatabe, Takafumi,Suzuki, Kosuke,Sasano, Yusuke,Iwabuchi, Yoshiharu,Hasegawa, Jun-ya,Mizuno, Noritaka,Yamaguchi, Kazuya
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- Nickel-Catalyzed Amination of Aryl Chlorides with Amides
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A nickel-catalyzed amination of aryl chlorides with diverse amides via C-N bond cleavage has been realized under mild conditions. A broad substrate scope with excellent functional group tolerance at a low catalyst loading makes the protocol powerful for synthesizing various aromatic amines. The aryl chlorides could selectively couple to the amino fragments rather than the carbonyl moieties of amides. Our protocol complements the conventional amination of aryl chlorides and expands the usage of inactive amides.
- Li, Jinpeng,Huang, Changyu,Wen, Daheng,Zheng, Qingshu,Tu, Bo,Tu, Tao
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supporting information
p. 687 - 691
(2021/01/09)
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- Novel clamp metal complex and application thereof
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The invention discloses a method for preparing a novel clamp-shaped complex and application of the novel clamp-shaped complex in the reaction of catalytic hydrogenation of carboxylic acid ester compounds to produce corresponding alcohols and reaction of carbon dioxide catalytic hydrogenation to form formamide compounds. Carboxylic acid esters and hydrogen as raw materials or carbon dioxide, hydrogen and amine compounds as raw materials are reacted in an organic solvent condition or a solvent-free condition in the presence of a transition metal complex as a catalyst to respectively form the corresponding alcohol compounds and/or corresponding formamide compounds. The method has the advantages of being high in reaction efficiency, good in selectivity, mild in conditions, economical, environmentally-friendly, and simple in operation, and has good promotion and application prospects.
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Paragraph 0240; 0241; 0242; 0258; 0259; 0260; 0261
(2019/04/26)
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- METHOD FOR PREPARING FORMAMIDE COMPOUND
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Disclosed is a method for preparing a formamide compound, the method uses carbon dioxide, hydrogen and an amine compound as raw materials and a transition metal complex as a catalyst, and the reaction is carried out in an organic solvent or in the absence of a solvent to form a formamide compound. The method of the present invention is an effective method of chemical utilization of carbon dioxide, which has the advantages of high reaction efficiency, a good selectivity, mild conditions, economic and environmental protection, being simple and convenient to operate and the like, and has a good popularization and application prospect.
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Paragraph 0195-0196
(2018/02/28)
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- Synthesis of formamides containing unsaturated groups by: N -formylation of amines using CO2 with H2
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Formamides have wide applications in the industry and have been synthesized using CO2 as a carbon source and H2 as a reducing agent. However, previous systems required a noble catalyst and high temperature to achieve high efficiency, and the substrate scope was mostly limited to saturated amines. The selective N-formylation of amines containing unsaturated groups using CO2 and H2 is challenging because the efficient catalysts for the N-formylation are usually very active for hydrogenation of the unsaturated groups. Herein, we achieved for the first time a selective and efficient N-formylation of amines containing unsaturated groups using CO2 and H2 with a Cu(OAc)2-4-dimethylaminopyridine (DMAP) catalytic system. The substrates were converted to the desired formamides, while the unsaturated groups, such as the carbonyl group, the CC bond, CN bond and the ester group remained. The main reason for the excellent selectivity of the Cu(OAc)2-DMAP catalytic system was that it was very active for the N-formylation reaction, but was not active for the hydrogenation of the unsaturated groups.
- Liu, Hangyu,Mei, Qingqing,Xu, Qingling,Song, Jinliang,Liu, Huizhen,Han, Buxing
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supporting information
p. 196 - 201
(2017/08/15)
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- Electro-Fenton treatment of imidazolium-based ionic liquids: Kinetics and degradation pathways
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In this study, the removal of five imidazolium-based ionic liquids (ILs) from water was accomplished by a heterogeneous electro-Fenton treatment. Different ILs were selected in order to study the effect of the alkyl chain length and the nature of the anion. Initially, the effect of the catalyst (iron alginate beads) dosage and current were evaluated. The results showed that the optimum conditions were attained when operating with 4.27 g of catalyst and 0.3 A, achieving degradation yields and TOC reductions higher than 95% after 90 min and 80% after 480 min, respectively. Regarding the ILs with common cations, lower degradation rates were obtained for those with longer alkyl chains, thus 1-ethyl-3-methylimidazolium dicyanamide, exhibits faster degradation than 1-hexyl-3-methylimidazolium dicyanamide and 1-butyl-3-methylimidazolium dicyanamide. In addition, the influence of the counter anions on the oxidation rate of different ILs under an electro-Fenton treatment was demonstrated, following the order: methylsulfate > dicyanamide > acetate. The Microtox ecotoxicity tests of the initial and treated samples revealed that none of the three studied ILs with shorter alkyl chain lengths showed toxicity and only 1-hexyl-3-methylimidazolium dicyanamide and 1-butyl-3-methylimidazolium dicyanamide presented toxic levels, with EC50 values of 269.85 and 47.55 mg L-1, respectively. Nonetheless, after 480 min of heterogeneous electro-Fenton treatment at 0.3 A, the toxicity of both was completely reduced. Finally, to confirm the mineralization of these compounds, the identification of several reaction intermediates in the heterogeneous electro-Fenton treatment of three ILs was assayed and a plausible degradation pathway was proposed.
- Bocos, Elvira,Pazos, Marta,Sanromán, M. ángeles
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p. 1958 - 1965
(2016/01/20)
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- Highly efficient ruthenium-catalyzed N-formylation of amines with H2 and CO2
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A highly efficient catalyst system based on ruthenium-pincer-type complexes has been discovered for N-formylation of various amines with CO2 and H2, thus affording the corresponding formamides with excellent productivity (turnover numbers of up to 1940000 in a single batch) and selectivity. Using a simple catalyst recycling protocol, the catalyst was reused for 12 runs in N,N-dimethylformamide production without significant loss of activity, thus demonstrating the potential for practical utilization of this cost-effective process.
- Zhang, Lei,Han, Zhaobin,Zhao, Xiaoyu,Wang, Zheng,Ding, Kuiling
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supporting information
p. 6186 - 6189
(2015/05/20)
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- Reaction of aliphatic amines with 49% formic acid. 1-hexylamine, di-1-hexylamine, N,N-dimethyl-1-hexylamine, 1-dodecylamine, N,N-dimethyl-1-dodecylamine and N,N-dimethyl-1-butylamine
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Two primary amines, 1-hexylamine 2, 1-dodecylamine 19, one secondary amine, di-1-hexylamine 18, and three tertiary amines, N,N-dimethyl-1-hexylamine 6, N,N-dimethyl-1-butylamine 3, and N,N-dimethyl-1-dodecylamine 22 were each heated at 150°C, 250°C or 350°C with 49% aqueous formic acid for varying periods of time. The aliphatic primary amines underwent easy N-formylation and subsequent reduction to give N-methyl- and N,N-dimethylalkylamines. Especially at higher temperatures, other reactions intervened including elimination of NH3 to the corresponding alkenes followed by partial double bond isomerization. Tertiary amines were more reactive at higher temperatures undergoing hydrolysis and reductive cleavages to secondary and primary amines, which subsequently followed the reaction sequences seen for primary amines. This series of saturated amines showed none of the cleavage into smaller fragments that was observed in the reductive alkylation of pyridine and 4-methylpyridine to a series of N-alkylpiperdines. This result reinforces the bis-aza-retro-Aldol-fragmentation mechanism postulated for the formation of the N-alkylpiperidines. Johann Ambrosius Barth 1997.
- Katritzky, Alan R.,Parris, Roslyn L.,Ignatchenko, Elena S.,Allin, Steven M.,Siskin, Michael
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