- Self-regulated catalysis for the selective synthesis of primary amines from carbonyl compounds
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Most current processes for the general synthesis of primary amines by reductive amination are performed with enormously excessive amounts of hazardous ammonia. It remains unclear how catalysts should be designed to regulate amination reaction dynamics at a low ammonia-to-substrate ratio for the quantitative synthesis of primary amines from the corresponding carbonyl compounds. Herein we show a facile control of the reaction selectivity in the layered boron nitride supported ruthenium catalyzed reductive amination reaction. Specifically, locating ruthenium to the edge surface of layered boron nitride leads to an increased hydrogenation activity owing to the enhanced interfacial electronic effects between ruthenium and the edge surface of boron nitride. This enables self-accelerated reductive amination reactions which quantitatively synthesize structurally diverse primary amines by reductive amination of carbonyl compounds with twofold ammonia. This journal is
- Fan, Xiaomeng,Gao, Jin,Gao, Mingxia,Jia, Xiuquan,Ma, Jiping,Xu, Jie
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supporting information
p. 7115 - 7121
(2021/09/28)
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- Selective Synthesis of Furfurylamine by Reductive Amination of Furfural over Raney Cobalt
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Effect of metal nature on reductive amination was investigated with biomass-based furfural as a typical substrate. Among the tested heterogeneous metal catalysts, cobalt proved to be the most effective metal for the synthesis of the corresponding primary amine. Under a relatively mild reaction condition, 98.9 % yield of furfurylamine was obtained over Raney Co and it can be reused more than eight times without a significant decrease in the catalytic performance. By extensively studying the catalytic pathways and reaction mechanism, it is found that the selectivity to primary amine and secondary amine was governed by the relative rate of hydrogenolysis and hydrogenation of the Schiff base intermediate. The superiority of Raney Co in furfurylamine synthesis can be ascribed to its high efficiency on hydrogenolysis of the Schiff base intermediate and its low performance in the hydrogenation of the Schiff base, carbonyl group and furan ring. Furthermore, ammonia greatly promoted the catalytic hydrogenolysis of the Schiff base intermediate over Raney Co without clear deactivation of the metal active sites.
- Zhou, Kuo,Chen, Bixian,Zhou, Xiaoting,Kang, Shimin,Xu, Yongjun,Wei, Jinjia
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p. 5562 - 5569
(2019/11/03)
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- Exploration of the Role of Double Schiff Bases as Catalytic Intermediates in the Knoevenagel Reaction of Furanic Aldehydes: Mechanistic Considerations
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This paper presents mechanistic considerations on an efficient, green, and solvent-free Knoevenagel procedure for the chemical transformation of furanic aldehydes into their corresponding α,β-unsaturated compounds. In the proposed mechanism furanic aldehydes react with ammonia, released from ammonium salts, to form a catalytically active double Schiff base. The catalytic intermediates involved in the condensation step are characterized.
- Van Schijndel, Jack,Canalle, Luiz Alberto,Molendijk, Dennis,Meuldijk, Jan
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supporting information
p. 1983 - 1988
(2018/09/18)
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- Deep eutectic solvent catalyzed eco-friendly synthesis of imines and hydrobenzamides
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The urea-choline chloride-based deep eutectic solvent was found to be an efficient catalyst and reaction media for the additive-free synthesis of imines (Schiff bases) and hydrobenzamides by the reaction of aldehydes with amines and ammonia in good to high yields. Outstanding features of this protocol were the general and atom-economical reaction, absence of external catalysts and additives, simple workup, and availability and recycling of urea-choline chloride as a green solvent. Graphical abstract: (Chemical Equation Presented).
- Azizi, Najmedin,Edrisi, Mahtab
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p. 1695 - 1698
(2015/09/21)
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- Studies on the reaction of diimines with thiourea: Synthesis and solvent-induced cis/trans-isomerization of 1,3,5-triazinane-2-thiones
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The reaction of N,Nc-bis(arylmethylidene)arylmethane diimines with thiourea under reflux in methanol was studied. The reaction gave a diastereomeric mixture of 4,6-disubstituted 1,3,5-triazinane-2-thiones in good yields. Two diastereoisomers of 4,6-diphenyl-1,3,5-triazinane-2-thione were detected in a solution of CDCl3 by NMR analysis. According to the NMR studies, the cisdiastereoisomer undergoes a solvent-induced cis/trans-isomerization process, producing the trans-diastereoisomer in DMSO. The stereochemistry of the trans-diastereoisomer was determined by Xray crystallographic analysis.
- Kaboudin, Babak,Ghasemi, Tahereh,Yokomatsu, Tsutomu
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experimental part
p. 3089 - 3093
(2009/12/28)
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- Synthesis of N,N-di(arylmethylidene)arylmethanediamines by flash vacuum pyrolysis of arylmethylazides
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Flash vacuum pyrolysis of arylmethylazides 7a-d gave 2,4-diazapentadienes 5a-d in high yield (76-92%). The thermal cyclization of 5a-d gave cis-imidazolines 1a-d, further heating or Swern oxidation of 1a-d gave dehydrogenated products, imidazoles 2a-d.
- Chou, Chin-Hsing,Chu, Li-Tse,Chiu, Shao-Jung,Lee, Chin-Fan,She, Yao-Teng
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p. 6581 - 6584
(2007/10/03)
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- A mild and highly efficient protocol for the one-pot synthesis of primary α-amino phosphonates under solvent-free conditions
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Under solvent-free reaction conditions and in the presence of solid LiClO4 a novel and mild protocol for the one-pot, three-component synthesis of primary α-amino phosphonates from an aldehyde, hexamethyldisilazane and a trialkyl phosphite is described giving high yields and having short reaction times. The same products are obtained in very low yields, when the three-component reaction is carried out under microwave irradiation and in the absence of solid LiClO4. Examples of some prepared 1-aryl-N,N′-bis(arylidene)methanediamines are also described.
- Azizi, Najmedin,Rajabi, Fatemeh,Saidi, Mohammad R.
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p. 9233 - 9236
(2007/10/03)
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- Microwave-assisted rapid and selective synthesis of cis- and trans-2,4,5-triarylimidazolines from aromatic aldehydes
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Microwave irradiation of a mixture of aromatic aldehydes and hexamethyldisilazane in the presence of a solid catalyst such as alumina afforded methanediamines which were efficiently converted to either cis- or trans-2,4,5-triarylimidazolines depending on the base used. A one-pot selective synthesis of cis- and transimidazolines from aromatic aldehydes was achieved under microwave irradiation.
- Uchida, Hitoshi,Tanikoshi, Hirofumi,Nakamura, Shuichi,Reddy, Paidi Yella,Toru, Takeshi
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p. 1117 - 1120
(2007/10/03)
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