- Direct synthesis of imines by 9-azabicyclo-[3,3,1]nonan-N-oxyl/KOH-catalyzed aerobic oxidative coupling of alcohols and amines
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A simple and efficient method for preparation of imines by the oxidative coupling of benzyl alcohols with aromatic amines or aliphatic amines was developed. The reaction was catalyzed by 9-azabicyclo[3.3.1]nonan-N-oxyl (ABNO)/KOH with air as the economic and green oxidant. Under the optimal reaction conditions, a variety of imines were obtained in 80%-96% isolated yields.
- Wan, Yan,Ma, Jia-Qi,Hong, Chao,Li, Mei-Chao,Jin, Li-Qun,Hu, Xin-Quan,Hu, Bao-Xiang,Mo, Wei-Min,Sun, Nan,Shen, Zhen-Lu
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- Direct synthesis of imines from nitro compounds and biomass-derived carbonyl compounds over nitrogen-doped carbon material supported Ni nanoparticles
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The selective synthesis of imines from biomass-derived chemicals over heterogeneous non-noble metal catalysts is of great importance for organic transformation. Herein, non-noble heterogeneous nitrogen-doped carbon supported Ni catalysts (abbreviated as Ni/CN-MgO-T, whereTrepresents the pyrolysis temperature) have been facilely prepared from the simple pyrolysis of Ni precursors and biomass, and Ni/CN-MgO-600 with the smallest size of Ni nanoparticles demonstrated the highest catalytic activity. The reductive coupling of nitroarenes and carbonyl compounds could be performed under mild conditions (80 °C, and 10 bar H2), affording structurally-diverse imines with high to excellent yields (84.2-98.1%). Thanks to the mild reaction conditions, the developed method showed good tolerance to other functional groups such as nitriles, halogen and vinyl groups.
- Li, Bo,Wang, Yanxin,Chi, Quan,Yuan, Ziliang,Liu, Bing,Zhang, Zehui
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p. 4464 - 4471
(2021/03/15)
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- Highly chemoselective synthesis of imine over Co/Zn bimetallic MOFs derived Co3ZnC-ZnO embed in carbon nanosheet catalyst
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One-pot direct synthesis of imines via reductive amination of nitroarenes with aromatic aldehydes remains a great challenge due in part to its over-hydrogenation of imines to secondary amines. Herein, a novel Co3ZnC and ZnO supported on N-doped carbon nanosheet catalyst with the thickness of ca. 5.0 nm was fabricated through the direct pyrolysis of a Co/Zn bimetallic MOFs at 500 °C (named as Co3ZnC-ZnO/NC-500). Surprisingly, the developed Co3ZnC-ZnO/NC-500 catalyst delivers 99.9 % conversion of nitrobenzene and 98.5 % selectivity to N-benzylideneaniline in one-pot reductive amination of nitrobenzene with benzaldehyde. Various characterizations (including as SEM, XRD, TEM, AFM, XPS, Raman and N2 adsorption–desorption) have revealed that the generated small size of Co3ZnC alloy, abundant structural defects, larger specific surface area (105.5 m2·g?1) as well as more basic sites are responsible for the outstanding catalytic activity of Co3ZnC-ZnO/NC-500 catalyst for tandem reaction. Moreover, the Co3ZnC-ZnO/NC-500 catalyst exhibits high stability during the recycling experiments without the loss of its catalytic activity. Notably, the results of contrast experiments have demonstrated that the intentional introduction of ZnO in Co3ZnC-ZnO/NC-500 catalyst plays a key role in the selectivity to N-benzylideneaniline in the tandem reaction. This study provides a new guideline for designing tandem catalysts with high selectivity.
- Li, Guangming,Li, Jingfang,Li, Weizuo,Li, Xuewei,Mao, Guijie,She, Wei,Wang, Jing
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- Copper-Catalyzed Intramolecular Amination of C(sp3)-H Bond of Secondary Amines to Access Azacycles
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The cross-coupling of C-N bond directly from inert C-H bonds is an ideal approach to synthesize saturated azacycles due to its high efficiency and atom economy. In this article, a copper-catalyzed intramolecular amination via the cross coupling of C(sp3)-H and N-H bonds of secondary amine has been reported, which exhibit excellent chemo- and regioselectivity, extensive substrate scope, and functional group tolerance in good to excellent yield, offering an efficient pathway to build nitrogen-containing heterocycle skeletons.
- Jin, Ruo-Xing,Dai, Jing-Cheng,Li, Yan,Wang, Xi-Sheng
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supporting information
p. 421 - 426
(2021/01/26)
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- Metal-free regioselective C-H amination for the synthesis of pyrazole-containing 2H-indazoles
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A general and practical regioselective approach for the C-H amination of 2H-indazoles under transition-metal-free conditions was developed. A series of substrates were tested showing eminent functional group tolerance and affording the C-N functionalization products in good to excellent yields. Mechanism studies revealed that a radical process was involved in this transformation.
- Wang, Kai,Wei, Tingting,Zhang, Yujia,Hou, Jiahao,Bai, Renren,Xie, Yuanyuan
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p. 1787 - 1794
(2021/03/14)
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- One-Pot Synthesis of Schiff Bases by Defect-Induced TiO2- x-Catalyzed Tandem Transformation from Alcohols and Nitro Compounds
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Schiff bases that are generally formed from condensation reactions of aldehydes (or ketones) and amino groups could also be produced by a photodriven one-pot tandem reaction between alcohols and nitro compounds, in our case. Herein, TiO2-x porous cages derived from NH2-MIL-125 by a self-sacrificing template route are used to study the organic transformation and exhibit 100% conversion efficiency of nitrobenzene and 100% selectivity for Schiff bases in the system of benzyl alcohol (5 mL) and nitrobenzene (41 μL) upon light irradiation, but hydrogen by dehydrogenation of benzyl alcohol cannot be detected. Successful occurrence of the organic transformation is mainly attributed to Ti(III)-oxygen vacancy associates. Surface oxygen vacancy-related Ti(III) sites are responsible for binding with nitro groups, and low-coordinated Ti5c sites selectively adsorb hydroxyl groups of benzyl alcohol. The Ti(III) and oxygen vacancy associates capture photogenerated electrons for achievement of multielectron reduction of nitrobenzene and the subsequent Schiff base condensation reaction with the as-formed benzaldehyde.
- Chen, Liyong,Fang, Qiang,Shen, Xiaoshuang,Tong, Jing,Wang, Jinfeng,Wang, Yao,Zhang, Hui
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supporting information
p. 10715 - 10721
(2021/07/26)
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- Photocatalytic one-pot multidirectional N-alkylation over Pt/D-TiO2/Ti3C2: Ti3C2-based short-range directional charge transmission
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Visible-light-induced one-pot, multistep, and chemoselectivity adjustable reactions highlight the economical, sustainable, and green process. Herein, we report Pt nanoparticles dispersed on S and N co-doped titanium dioxide/titanium carbide (MXene) (3%Pt/
- Jiang, Heyan,Sheng, Meilin,Li, Yue,Kong, Shuzhen,Bian, Fengxia
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- Iron-Catalyzed Hydrogen Transfer Reduction of Nitroarenes with Alcohols: Synthesis of Imines and Aza Heterocycles
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A straightforward and selective reduction of nitroarenes with various alcohols was efficiently developed using an iron catalyst via a hydrogen transfer methodology. This protocol led specifically to imines in 30-91% yields, with a good functional group tolerance. Noticeably, starting from o-nitroaniline derivatives, in the presence of alcohols, benzimidazoles can be obtained in 64-72% yields when the reaction was performed with an additional oxidant, DDQ, and quinoxalines were prepared from 1,2-diols in 28-96% yields. This methodology, unprecedented at iron for imines, also provides a sustainable alternative for the preparation of quinoxalines and benzimidazoles.
- Wu, Jiajun,Darcel, Christophe
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p. 1023 - 1036
(2021/01/09)
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- Efficient Imine Formation by Oxidative Coupling at Low Temperature Catalyzed by High-Surface-Area Mesoporous CeO2 with Exceptional Redox Property
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High-surface-area mesoporous CeO2 (hsmCeO2) was prepared by a facile organic-template-induced homogeneous precipitation process and showed excellent catalytic activity in imine synthesis in the absence of base from primary alcohols and amines in air atmosphere at low temperature. For comparison, ordinary CeO2 and hsmCeO2 after different thermal treatments were also investigated. XRD, N2 physisorption, UV-Raman, H2 temperature-programmed reduction, O2 temperature-programmed desorption, EPR spectroscopy, and X-ray photoelectron spectroscopy were used to unravel the structural and redox properties. The hsmCeO2 calcined at 400 °C shows the highest specific surface area (158 m2 g?1), the highest fraction of surface coordinatively unsaturated Ce3+ ions (18.2 %), and the highest concentration of reactive oxygen vacancies (2.4×1015 spins g?1). In the model reaction of oxidative coupling of benzyl alcohol and aniline, such an exceptional redox property of the hsmCeO2 catalyst can boost benzylideneaniline formation (2.75 and 5.55 mmol (Formula presented.) h?1 based on >99 % yield at 60 and 80 °C, respectively) in air with no base additives. It can also work effectively at a temperature of 30 °C and in gram-scale synthesis. These are among the best results for all benchmark ceria catalysts in the literature. Moreover, the hsmCeO2 catalyst shows a wide scope towards primary alcohols and amines with good to excellent yield of imines. The influence of reaction parameters, the reusability of the catalyst, and the reaction mechanism were investigated.
- Wu, Shipeng,Wang, Yinghao,Cao, Qiue,Zhao, Qihua,Fang, Wenhao
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supporting information
p. 3019 - 3028
(2020/12/11)
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- Efficient imine synthesisviaoxidative coupling of alcohols with amines in an air atmosphere using a mesoporous manganese-zirconium solid solution catalyst
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Direct oxidative coupling of alcohols with amines using a non-precious metal oxide catalyst under mild conditions is highly desirable for imine synthesis. In this work, a mesoporous Mn1ZrxOysolid solution catalyst prepared by a co-precipitation method showed excellent catalytic performance in imine synthesis from primary alcohols and amines without base additives in an air atmosphere. XRD, N2physisorption, H2-TPR, O2-TPD, EPR and XPS were comprehensively used to unravel its structural, redox and amphoteric properties that closely depended on the interaction between MnOyand ZrO2with a variable Zr ratio. The Mn1Zr0.5Oycatalyst presented the highest fractions of Mn3+ions and reactive oxygen species on the surface, and the highest concentrations of acidic-basic sites, which were disclosed to play important roles in activating alcohols and molecular O2in the rate-determining step. In the model reaction of oxidative coupling of benzyl alcohol with aniline, such enhanced features of the Mn1Zr0.5Oycatalyst can promote the intrinsic catalytic activity (iTOF of 1.87 h?1) and boost benzylideneaniline formation (5.56 mmol gcat.?1h?1) based on a >99% yield at 80 °C respectively at a fast response. It can also work effectively at a room temperature of 30 °C, as well as for the gram-grade synthesis. This is one of the best results among all the MnOy-based catalysts in the literature. Moreover, this catalyst showed good stability and a wide substrate scope with good to excellent yields of imines.
- Wu, Shipeng,Zhang, Hao,Cao, Qiue,Zhao, Qihua,Fang, Wenhao
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p. 810 - 822
(2021/02/26)
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- Rational Design of Cobalt-Platinum Alloy Decorated Cobalt Nanoparticles for One-Pot Synthesis of Imines from Nitroarenes and Aldehydes
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Developing high-performance heterogeneous catalysts for one-pot reductive amination reactions is critically important for pharmaceutical and agrochemical synthetic industries. In this work, N-doped carbon nanotubes supported CoPt alloy decorated Co nanoparticles (NPs) are successfully fabricated. As a consequence, the resultant catalyst exhibits desirable activity, selectivity and stability toward the one-pot synthesis of imines. More importantly, the extensive experimental studies and density function theory (DFT) calculations results reveal that the high catalytic activity of the catalyst is mainly due to the co-existence of CoPt alloy NPs and Co NPs with Co?Nx active sites. The high selectivity of imines could be ascribed to the following aspects: (1) competitively preferred adsorption of nitroarenes to avoid side-hydrogenation of aldehydes; (2) weakened adsorption of imines to minimize its over-hydrogenation. This work may provide a promising direction and strategy to design high-performance reductive amination catalysts for industrial applications.
- Gong, Wanbing,Han, Miaomiao,Chen, Chun,Lin, Yue,Wang, Guozhong,Zhang, Haimin,Zhao, Huijun
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p. 5948 - 5958
(2020/10/02)
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- Catalyst- And Solvent-Free Synthesis of α-Amino Polyfluoroalkylphosphonates from Bis(fluoroalkyl) Phosphonates and Aldimines
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The catalyst- and solvent-free reaction between bis(fluoroalkyl) phosphonates and aldimines occurs under mild conditions (20-22 °C, 0.25-4 h) to afford a new family of α-amino polyfluoroalkylphosphonates in up to quantitative yields.
- Arbuzova, Svetlana N.,Gusarova, Nina K.,Kazantseva, Tatyana I.,Kolyvanov, Nikita A.,Trofimov, Boris A.,Verkhoturova, Svetlana I.,Zinchenko, Sergey V.
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p. 1531 - 1540
(2020/05/19)
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- Catalyst- And solvent-free efficient access to: N -alkylated amines via reductive amination using HBpin
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A sustainable approach which works under catalyst- and solvent-free conditions for the synthesis of structurally diverse secondary amines has been uncovered. This one-pot protocol works efficiently at room temperature and is compatible with a wide range of sterically and electronically diverse aldehydes and primary amines. Notably, this simple process offers scalability, excellent functional group tolerance, chemoselectivity, and is also effective at the synthesis of biologically relevant molecules. This journal is
- Bauri, Somnath,Pandey, Vipin K.,Rit, Arnab
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supporting information
p. 3853 - 3857
(2020/07/27)
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- A Highly Selective Manganese-Catalyzed Synthesis of Imines under Phosphine-Free Conditions
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An efficient and highly selective phosphine-free NN-manganese(I) complex catalyst system was developed for the acceptorless dehydrogenative coupling of alcohols with amines to form imines. The coupling reactions underwent at 3 mol % catalyst loading, and a large range of alcohols and amines with diverse functional groups was applied, including challenging diol and diamine. The target imine products were obtained in good to excellent yields. The present work provides an alternative method to construct highly active nonprecious metal complex catalysts based on phosphine-free ligands.
- Chai, Huining,Yu, Kun,Liu, Bo,Tan, Weiqiang,Zhang, Guangyao
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p. 217 - 226
(2020/01/31)
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- Ruthenium N-Heterocyclic Carbene Complexes for Chemoselective Reduction of Imines and Reductive Amination of Aldehydes and Ketones
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Chemoselective reduction of imines to secondary amines is catalyzed efficiently by tethered and untethered, half-sandwich ruthenium N-heterocyclic carbene (NHC) complexes at room temperature. The untethered Ru-NHC complexes are more efficient as catalysts for the reduction of aldimines and ketimines than the tethered complexes. Using the best untethered complex as a catalyst, electronic and steric demands on the reaction was probed using a series of imines. Chemoselectivity of the catalyst towards imine reduction was tested by performing inter and intramolecular competitive reactions in a variety of ways. The catalyst exhibits a very high TON and TOF under anaerobic conditions.
- Kathuria, Lakshay,Samuelson, Ashoka G.
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supporting information
(2020/06/17)
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- Method for synthesizing aluminum phosphate molecular sieve catalytic imine
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The invention discloses a method for catalyzing synthesis of an imine by using an aluminum phosphate molecular sieve, and belongs to the technical field of catalytic synthesis of imines. Under the action of an HP-MeAlPO-5 molecular sieve, air or oxygen is used as an oxidant, and an amine and an alcohol which contain different substituents are directly subjected to oxidative coupling to synthesizethe imine under mild conditions. According to the method provided by the invention, the reaction conditions of the adopted catalytic system are mild, and the TOF is high; a reaction can efficiently catalyze the synthesis of the imine at room temperature under air; and the method can adopt transition metals, which are cheap and easy to obtain, such as iron, cobalt and nickel as a molecular sieve dopant, and the availability of the molecular sieve is improved.
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Paragraph 0053-0055
(2020/06/02)
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- Ultrasound-assisted construction of a Z-scheme heterojunction with g-C3N4 nanosheets and flower-like Bi2WO6 microspheres and the photocatalytic activity in the coupling reaction between alcohols and amines under visible light irradiation
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Flower-like Bi2WO6 microspheres and bulk g-C3N4 were prepared by the hydrothermal method and high-temperature calcining method, respectively. A new method based on the combination of ultrasonic stripping and mechanical stirring was used to obtain uniform composite x-Bi2WO6/g-C3N4 (x is the Bi2WO6 mass ratio) photocatalysts with a Z-scheme heterojunction. In the reaction of benzyl alcohol and aniline to form imine, the optimal composite, 30percent-Bi2WO6/g-C3N4, showed a conversion rate of 87.6percent, which is much higher than that of pure Bi2WO6 and g-C3N4. Characterization by SEM and TEM showed that the ultrasonically stripped g-C3N4 significantly reduced the radial dimension compared to bulk g-C3N4. A uniformly dispersed photocatalytic material was formed, and it maintained a flower-like microsphere structure. Materials characterized by N2 adsorption–desorption isotherms (BET) showed that the specific surface area of the g-C3N4 nanosheets increased by approximately ten times after ultrasonic stripping. The photostability of the composite was verified by cyclic experiments. Under visible light irradiation, the activation energy of the coupling reaction between benzyl alcohol and aniline was found to be decreased by 29.8 kJ mol?1. A capture experiment was used to verify the active species in the photocatalytic system, with the reaction found to be mainly completed through the synergistic action of h+, e? and ?O2?.
- Hao, Xueli,Li, Enbo,Li, Haiying,Li, Jingyi,Wang, Yan,Wang, Zhibao,Yu, Xiujuan,Zhang, Zhiying
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- Insight into Ce Doping Induced Oxygen Vacancies over Ce-Doped Mno2 Catalysts for Imine Synthesis
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The pursuit of modern sustainable chemistry has stimulated the development of innovative catalytic processes that enable chemical transformations to be performed under mild and clean conditions with high efficiency. Here, an amorphous sheet-like MnO2 (Ce-doped MnO2: CMBO) was obtained after Ce doping, which exhibits excellent catalytic performance for the oxidation coupling of alcohol and aniline. Conversion of 99% and a selectivity of 99% could be achieved within 6 h at 60 oC under air atmosphere, and the formation rate of target product was up to 30.2 μmol·h–1·m–2. Based on a series of characterizations, it was found that the doping of Ce into the MnO2 could increase the concentration of the oxygen vacancies, thus forming abundant active surface oxygen species and favoring the mobility of lattice oxygen, which are the main reasons for the greatly enhanced catalytic performance of CMBO. This work indicates that increasing oxygen vacancy by element doping may serve as a facile and efficient way to enhance catalytic performance of transition metal oxide.
- Shen, Haidong,Bu, Jun,Wang, Wenbin,Wu, Chen,Cao, Yueling,Zhang, Baoliang,Zhang, Qiuyu,Zhang, Hepeng
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supporting information
p. 1353 - 1359
(2020/08/25)
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- Tuning effect of amorphous Fe2O3on Mn3O4for efficient atom-economic synthesis of imines at low temperature: Improving [O] transfer cycle of Mn3+/Mn2+in Mn3O4
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A facile and scaled-up synthesis route to efficient and environment-friendly metal oxide catalysts with desirable properties is of great practical importance, owing to their excellent performance as heterogeneous catalysts in organic synthesis. Herein, a novel amorphous Fe2O3 modified Mn3O4 catalyst (Fe5Mn5-100) has been prepared by adopting a simple co-precipitation method following low temperature baking. Fe5Mn5-100 showed exceptionally high catalytic activity for the atom-economic production of imine from benzyl alcohol with aniline, giving a 98% imine yield at 60 °C in only 3 h, which is higher than all of the reported non-noble and noble metal catalysts. Importantly, Fe5Mn5-100 could still exhibit extraordinary catalytic performance on a large-scale reaction without any solvent, including the frequently used toxic mesitylene, xylene or toluene. Interestingly, the amorphous Fe2O3-100 provided no catalytic activity, and pure Mn3O4-100 showed very inferior catalytic activity towards this reaction. Further detailed characterizations and experimental results revealed that amorphous Fe2O3 plays an important role in expediting the [O] transfer cycle of Mn3+/Mn2+ in Mn3O4, and enhances the oxidation ability and acidity of Fe5Mn5-100. This discovery would provide a new avenue for the atom-economic and environment-friendly industrial synthesis of imine. This journal is
- Cao, Xiao,Gou, Galian,Long, Yu,Luo, Shicheng,Luo, Yutong,Ma, Jiantai,Qin, Jiaheng,Wang, Kaizhi,Wu, Wei
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p. 5628 - 5640
(2020/09/17)
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- Facile route for green synthesis of N-benzylideneaniline over bimetallic reduced graphene oxide: chemical reactivity of 2,3,4-substituted derivatives of aniline
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Mn–Co-decorated reduced graphene oxide (Mn–Co–rGO) was prepared by modified condensation method and characterized through XRD, SEM, EDX, FTIR and BET surface area analysis. The prepared sample was explored for its activity in the synthesis of N-benzylideneaniline (N-BA) using benzyl alcohol and PhNH2 as precursors. The catalyst has been used efficiently with high activity and selectivity for oxidation of benzyl alcohol to benzaldehyde in the presence of molecular oxygen, which further react with aniline to produced N-BA with sustainable catalytic activity up to five cycles. Furthermore, the effect of the nature and position of the substituent on aniline on the chemical reactivity of the nucleophile was studied theoretically using density functional calculations.
- Aman, Razia,Sadiq, Saima,Ali, Muhammad,Sadiq, Muhammad,Gul, Jehan,Saeed, Khalid,Khan, Adnan Ali,Shah, Sagheer Hussain
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p. 2947 - 2961
(2019/02/28)
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- Mild and efficient synthesis of secondary aromatic amines by one-pot stepwise reductive amination of arylaldehydes with nitroarenes promoted by reusable nickel nanoparticles
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The one-pot stepwise reductive amination of arylaldehydes with nitroarenes is described, using reusable nickel nanoparticles (Ni-pol) as catalyst and NaBH4 as mild, inexpensive, and safe reducing agent. The proposed catalytic system holds several advantages such as the use of a non-precious and earth-abundant metal, the facile separation of the catalyst from the reaction mixture by centrifugation, excellent stability towards air and moisture, very mild reaction conditions, good recyclability, broad substrate scope with good to excellent yields, and easy scalability (up to 1.0 g). FESEM analyses indicate that the active species are cubic nanocrystals of Ni in the average cross section value of 35 nm with a quite narrow (25–45 nm) and monomodal distribution, which becomes bimodal with the recycling reactions but without agglomeration.
- Fiore, Ambra Maria,Romanazzi, Giuseppe,Dell'Anna, Maria Michela,Latronico, Mario,Leonelli, Cristina,Mali, Matilda,Rizzuti, Antonino,Mastrorilli, Piero
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- Chemoselective Reduction of Imines Catalyzed by Ruthenium(II) Half-Sandwich Complexes: A Mechanistic Study
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Ruthenium half-sandwich complexes ligated to chiral 2-oxazolidinethiones or 2-thiozolidinethiones in the reduction of N-benzylideneaniline using silyl hydrides as reductants has been examined. The chemoselective reduction of imines takes place under mild conditions to afford the corresponding amines in nearly quantitative yield. Mechanistic studies indicate that dissociation of the ancillary ligands generate the active catalyst in all the complexes studied, which is the same species generated by [Ru(p-cymene)(Cl)2]2 under the reaction conditions. This results in the formation of a single catalytic species irrespective of the starting half-sandwich complex. Detailed mechanistic studies involving trapping of intermediates, in situ studies using mass spectrometry and NMR spectroscopy were carried out using the active catalyst generated by [Ru(p-cymene)(Cl)2]2. The mechanism of the reaction is dependent on the number of the hydrogen atoms in the reducing silane. The reaction proceeds via Gade-Hoffman pathway or Zheng-Chan pathway when a dihydro or trihydrosilane is the reductant. However, the use of a monohydrosilane, leads to longer reaction times presumably due to a change in the reaction pathway.
- Reshi, Noor U. Din,Kathuria, Lakshay,Samuelson, Ashoka G.
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p. 2947 - 2955
(2019/06/27)
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- Direct reductive coupling of nitroarenes and alcohols catalysed by Co-N-C/CNT@AC
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A non-noble heterogeneous catalyst-a Co, N and C composite encapsulated carbon nanotube grown in situ on the surface of activated carbon (Co-N-C/CNT@AC)-was fabricated via the pyrolysis-reduction process. Co-N-C/CNT@AC catalyzed the reductive coupling of structurally diverse nitroarenes and alcohols to imines and secondary amines under exogenous base- and solvent-free conditions. BET, TEM, SEM, XRD and XPS characterization showed that the exceptional catalytic property of Co-N-C/CNT@AC could be explained by its nanostructure, Co-N and basic N species. Our protocol had advantages of low cost, environment-friendliness, and good applicability. Furthermore, a reaction route of nitroarenes, amines and alcohols as the starting materials was proposed to improve the atom economy of the reductive coupling of nitroarenes with alcohols.
- Liu, Di,Yang, Ping,Zhang, Hao,Liu, Minjie,Zhang, Wenfei,Xu, Dongmei,Gao, Jun
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p. 2129 - 2137
(2019/04/27)
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- Switching the N-Alkylation of Arylamines with Benzyl Alcohols to Imine Formation Enables the One-Pot Synthesis of Enantioenriched α-N-Alkylaminophosphonates
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The selective N-alkylation of anilines with benzylic alcohols can be switched in favor of the dehydrogenative condensation process using the nitrile-ligated Kn?lker's complex by conducting the reaction either in a closed system under inert conditions, or in an open system in air. The selective formation of imines, containing reactive C=N bonds, provides an opportunity towards further functionalization. Indeed, a one-pot three-component condensation of alcohols, amines and phosphites, promoted by an iron-based Kn?lker-type complex in combination with a chiral BINOL-based phosphoric acid, provides access to enantioenriched α-N-alkylaminophosphonates.
- Hofmann, Natalie,Hultzsch, Kai C.
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supporting information
p. 3105 - 3111
(2019/06/08)
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- Method for preparing imine by utilizing copper catalyst to catalyze cross coupling of amine and alcohol
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The invention discloses a method for preparing imine by utilizing a copper catalyst to catalyze cross coupling of amine and alcohol. The method comprises the following steps: under the condition of nooxidant, adopting Cu/Al2O3 as a catalyst to catalyze the cross coupling of the amine and the alcohol so as to prepare the imine. The method disclosed by the invention has beneficial effects that thereaction system is simple, cocatalysts such as organic ligand, alkaline, and free radical of nitroxide do not need to be added, and simultaneously under the condition of no oxidant, the method utilizes Cu/Al2O3 to catalyze cross coupling of the amine and the alcohol so as to prepare the imine; the problem that the imine is easily peroxidated can be effectively solved; in addition, the catalyst Cu/Al2O3 used by the method is simple in preparation, is highly-effective and stable and is low in price.
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Paragraph 0036; 0037; 0038
(2019/02/04)
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- Efficient imine synthesis from oxidative coupling of alcohols and amines under air atmosphere catalysed by Zn-doped Al2O3 supported Au nanoparticles
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Direct oxidative coupling of alcohols and amines is regarded as an effective and green approach for imine synthesis under mild conditions. In this work, Zn-doped γ-Al2O3 supported Au nanoparticles was demonstrated as highly active and selective heterogeneous catalyst for a series of imine productions with good to excellent yields, from alcohols and amines via direct oxidative coupling under air atmosphere without extra base additives. Various physicochemical techniques, including ICP-MS, XRD, N2 physisorption, TEM, XPS and CO2-/NH3-TPD, were used to study the properties of the catalysts. Well-dispersed Au0 nanoparticles with a mean size of ca. 2.9 nm were found highly effective in activating alcohols in the presence of reactive amines. The amount of Zn2+ dopant and the calcination temperature of support during catalyst preparation showed crucial impact on tuning the intrinsic activity for oxidation of benzyl alcohol to benzaldehyde (i.e., the rate-determining step for the model reaction), which was disclosed to be related with the active surface oxygen species and the acidic-basic property of support. The 0.4% Au/Zn0.02Al2O3 catalyst calcined at 400 °C exhibited the highest TOF (39.1 h?1) at 60 °C based on a >99% yield to benzylideneaniline among all the ever-reported Au-based catalysts. Moreover, this catalyst could afford 98% yield to benzylideneaniline at only 30 °C and work effectively for the gram-scale synthesis. It also showed considerable stability after five consecutive recycling.
- Wu, Shipeng,Sun, Weixiao,Chen, Junjie,Zhao, Jinghan,Cao, Qiue,Fang, Wenhao,Zhao
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p. 110 - 121
(2019/08/01)
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- Bi-functional catalyst of porous N-doped carbon with bimetallic FeCu for solvent-free resultant imines and hydrogenation of nitroarenes
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The efficient and stable catalyst applied to the transformation of amines into the corresponding imines and hydrogenation of nitroarenes under mild reaction conditions is reported. The catalytic performance of porous N-doped carbon with FeCu (FeCu@NPC) catalyst are tested by aromatic alcohol-based N-alkylated of amines with solvent-free and hydrogenation of nitroarenes via N2H4·H2O. The results proved that the yield of these two reactions are all over 99.9% under optimum condition. Moreover, the synergistic effect of the catalyst for N-alkylated reaction was investigated through the kinetic study. The catalyst can be easily separated from reaction system by an external magnetism, and can be recycled and reutilized for at least 4 runs with conversions are all over 75%. The study of the catalyst indicated that it was suitable for the reactions in industry. Hence, the catalysis process by the inexpensive metals-based catalyst is green and sustainable.
- Wang, Kaizhi,Gao, Wenbing,Jiang, Pengbo,Lan, Kai,Yang, Ming,Huang, Xiaokang,Ma, Lei,Niu, Fang,Li, Rong
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- One-pot synthesis of Pd-promoted Ce-Ni mixed oxides as efficient catalysts for imine production from the direct: N -alkylation of amine with alcohol
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Ce-Ni mixed oxides with different Ni/Ce molar ratios, promoted by a rather low amount of Pd (0.2 wt%), were prepared by a simple one-pot precipitation method. The thus-synthesized CeNiXOY and Pd-CeNiXOY catalysts were applied respectively to the direct N-alkylation of amine and alcohol via oxidative coupling, under O2 in the absence of basic additives. The CeNiXOY catalyst could provide a >99% yield of imine in the model alkylation reaction of aniline with benzyl alcohol at 100 °C. The Pd-promoted Pd-CeNiXOY catalyst surprisingly showed an enhanced imine yield (>99%) at a mild temperature of 60 °C. This catalyst exhibited good reusability, and moreover, demonstrated high performance towards imine synthesis from various amines with alcohols. The presence of Pd species and the Ni/Ce molar ratio showed a synergistic impact on the conversion of aniline, as well as on the product selectivity, which was believed to be related to the improvement on the intrinsic activity of the oxidation of benzyl alcohol to benzaldehyde. Various physicochemical techniques, including ICP-MS, XRD, N2 adsorption-desorption, UV-Raman, H2-TPR, TEM, EPMA and XPS, were employed to study mainly the composition, structure and redox properties of the catalysts. The proportion of Ce3+ species and oxygen vacancies, which can be manipulated by the Ce-Ni redox system and the interaction between Ce and Ni, was crucial to the selective activation of alcohols in the presence of reactive amines. The activation of alcohol on the highly reactive Pd0 species was the other crucial factor.
- Zhang, Mengyuan,Wu, Shipeng,Bian, Longchun,Cao, Qiue,Fang, Wenhao
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p. 286 - 301
(2019/01/28)
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- Amorphous Fe2O3 improved [O] transfer cycle of Ce4+/Ce3+ in CeO2 for atom economy synthesis of imines at low temperature
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CeO2 based catalysts have been investigated in various catalytic reactions due to its unique reversible Ce3+/Ce4+ redox pair and physicochemical property, but its poor cycle efficiency and low reservoir limit its wide application in the fine chemicals industry. In this work, a novel amorphous Fe2O3 modified CeO2 catalytic system was developed by a facile co-precipitation method. The as-prepared samples were characterized in detail, and were employed for catalyzing the one-pot synthesis of imine from benzyl alcohol and aniline under air atmosphere at low temperature. The as-prepared sample with molar ratio of Fe:Ce = 8:2 dried at 100 °C (named Fe8Ce2-100) exhibited superhigh activity for atom economy synthesis of imine, which was much higher than the reported CeO2 catalyst, even higher than some noble metal catalysts. It is worth noting that pure amorphous Fe2O3-100 could not catalyze this reaction at all, and both pure CeO2-100 and the mechanical mixed sample with the same molar ratio of Fe:Ce exhibited much more inferior catalytic activity than Fe8Ce2-100. Combining characterization results and the catalytic activities of different catalysts at various reaction conditions, the enhanced catalytic activity of Fe8Ce2-100 could be ascribed to the novel synergistic effect between CeO2 and amorphous Fe2O3. Amorphous Fe2O3 plays the role of engine to greatly improve the [O] transfer cycle of Ce4+/Ce3+, as well as enhances the redox and amphoteric properties of the catalysts. This work firstly determines amorphous Fe2O3 can participate and facilitate the catalytic cycle for organic reaction, and may provide a significant strategy for designing polymetallic oxide catalyst towards organic aerobic transformation.
- Qin, Jiaheng,Long, Yu,Wu, Wei,Zhang, Wei,Gao, Zekun,Ma, Jiantai
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p. 161 - 174
(2019/02/15)
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- H2-Generation from Alcohols by the MOF-Based Noble Metal-Free Photocatalyst Ni/CdS/TiO2@MIL-101
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The synthesis of important classes of chemical compounds from alcohols helps to conserve Earth's fossil carbon resources, since alcohols can be obtained from indigestible and abundantly available biomass. The utilisation of visible light for the activation of alcohols permits alcohol-based C-N and C-C bond formation under mild conditions inaccessible with thermally operating hydrogen liberation catalysts. Herein, we report on a noble metal-free photocatalyst able to split alcohols into hydrogen and carbonyl compounds under inert gas atmosphere without the requirement of electron donors, additives, or aqueous reaction media. The reusable photocatalyst mediates C-N multiple bond formation using the oxidation of alcohols and subsequent coupling with amines. The photocatalyst consists of a CdS/TiO2 heterojunction decorated with co-catalytic Ni nanoparticles and is prepared on size-optimised colloidal metal-organic framework (MOF) crystallites.
- Tilgner, Dominic,Klarner, Mara,Hammon, Sebastian,Friedrich, Martin,Verch, Andreas,De Jonge, Niels,Kümmel, Stephan,Kempe, Rhett
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p. 842 - 847
(2019/08/26)
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- Unsymmetrical indazolyl-pyridinyl-triazole ligand-promoted highly active iridium complexes supported on hydrotalcite and its catalytic application in water
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Herein, an indazolyl-pyridinyl-triazole ligand was synthesized and its iridium complex supported on hydrotalcite was characterized via X-ray power diffraction (XRD), X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray (EDX) spectroscopy and transmission electron microscopy (TEM). This new heterogeneous catalyst bearing the unsymmetrical indazolyl-pyridinyl-triazole ligand exhibits high catalytic activity in water. Both functionalized amines and imines were obtained from the challenging selective reaction of benzylamines with arylamines through transfer hydrogenation and dehydrogenation under clean conditions. In particular, it was observed that this catalyst system showed good recovery performance in water. Mechanistic studies showed that this transformation occurs via amine dehydrogenation, hydrolysis and condensation processes. The direct capture of the reaction intermediate provides sufficient proof for this process.
- Ge, Chenyang,Sang, Xinxin,Yao, Wei,Zhang, Liang,Wang, Dawei
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supporting information
p. 1805 - 1812
(2018/04/30)
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- Photochemically Promoted Aza-Diels-Alder-Type Reaction: High Catalytic Activity of the Cr(III)/Bipyridine Complex Enhanced by Visible Light Irradiation
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Aza-Diels-Alder-type cycloaddition reactions between a range of N-arylimines and functionalized alkenes were effectively catalyzed by the Cr(III)/bipyridine complex under irradiation of blue light, to give the corresponding 1,2,3,4-tetrahydroquinoline derivatives in high yields with excellent diastereoselectivity. Typically, the reaction of benzylideneaniline with 1-vinyl-2-pyrrolidinone proceeded smoothly with a substrate-to-catalyst molar ratio (S/C) of 1000 and completed within 4 h at room temperature (20-25 °C), affording the cycloaddition product in 97% yield.
- Arai, Noriyoshi,Ohkuma, Takeshi
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p. 7628 - 7636
(2017/07/26)
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- Tunable Ligand Effects on Ruthenium Catalyst Activity for Selectively Preparing Imines or Amides by Dehydrogenative Coupling Reactions of Alcohols and Amines
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Selective dehydrogenative synthesis of imines from a variety of alcohols and amines was developed by using the ruthenium complex [RuCl2(dppea)2] (6 a: dppea=2-diphenylphosphino-ethylamine) in the presence of catalytic amounts of Zn(OCOCF3)2 and KOtBu, whereas the selective dehydrogenative formation of amides from the same sources was achieved by using another ruthenium complex, [RuCl2{(S)-dppmp}2] [6 d: (S)-dppmp=(S)-2-((diphenylphosphenyl)methyl)pyrrolidine], in the presence of catalytic amounts of Zn(OCOCF3)2 and potassium bis(trimethylsilyl)amide (KHMDS). Our previously reported ruthenium complex, [Ru(OCOCF3)2(dppea)2] (8 a), was the catalyst precursor for the imine synthesis, whereas [Ru(OCOCF3)2{(S)-dppmp}2] (8 d), which was derived from the treatment of 6 d with Zn(OCOCF3)2 and characterized by single-crystal X-ray analysis, was the pre-catalyst for the amide formation. Control experiments revealed that the zinc salt functioned as a reagent for replacing chloride anions with trifluoroacetate anions. Plausible mechanisms for both selective dehydrogenative coupling reactions are proposed based on a time-course study, Hammett plot, and deuterium-labeling experiments.
- Higuchi, Takafumi,Tagawa, Risa,Iimuro, Atsuhiro,Akiyama, Shoko,Nagae, Haruki,Mashima, Kazushi
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p. 12795 - 12804
(2017/09/06)
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- Method for preparing imine compound from alcohol and amine through catalytic oxidation
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The invention discloses a method for preparing an imine compound from alcohol and amine through catalytic oxidation. According to the method, an alcohol compound and an amine compound are used as reaction substrates, and a feeding mol ratio of the alcohol compound to the amine compound is 100: 100-60; 9-azabicyclo[3.3.1]nonane N-oxyl free radical is used as a catalyst, potassium hydroxide is used as an auxiliary agent, and a feeding mol ratio of the amine compound to the 9-azabicyclo[3.3.1]nonane N-oxyl free radical to potassium hydroxide is 100: 1-6: 10-50; air is used as an oxidizing agent, the reaction substrates are added into an organic solvent, and the mass of the used organic solvent is 2.5 to 5 times of the reaction substrate the amine compound; and a reaction is carried out at normal pressure at a temperature of 70 to 110 DEG C for 2 to 12 h, and aftertreatment is carried out after completion of the reaction so as to obtain the imine compound. The method provided by the invention is simple and safe to operate, reduces environmental cost due to usage of clean oxygen as the oxidizing agent and prevents the problem of transition-metal pollution by discarding usage of any transition-metal catalyst.
- -
-
Paragraph 0033
(2017/08/31)
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- One-Pot Catalytic Approach for the Selective Aerobic Synthesis of Imines from Alcohols and Amines Using Efficient Arene Diruthenium(II) Catalysts under Mild Conditions
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A green and efficient catalytic approach for the selective synthesis of imines in air at room temperature was achieved with the aid of newly synthesised diruthenium(II) complexes [(η6-p-cymene)2Ru2Cl2(μ-L)] containing substituted 1,2-diacylhydrazine ligands. All the new complexes were fully characterised by analytical and spectroscopic techniques. The solid-state structure of a representative complex was solved by single-crystal X-ray diffraction analysis. The diruthenium(II) complexes also enable the selective aerobic oxidation of alcohols to aldehydes. The catalytic reaction operates in the presence of air as a green and cheap oxidant, and releases water as the only by-product. A plausible mechanism is proposed for the imine formation, which is believed to proceed via an aldehyde intermediate.
- Saranya, Sundar,Ramesh, Rengan,Grzegorz Ma?ecki, Jan
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p. 6726 - 6733
(2017/12/07)
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- Osmium Hydride Acetylacetonate Complexes and Their Application in Acceptorless Dehydrogenative Coupling of Alcohols and Amines and for the Dehydrogenation of Cyclic Amines
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The preparation of new osmium hydride complexes, starting from OsH6(PiPr3)2 (1) and OsH2Cl2(PiPr3)2 (2), and their catalytic activity in acceptorless dehydrogenative coupling of alcohols and amines and in dehydrogenation of cyclic amines are reported. Complex 1 reacts with acetylacetone (Hacac) to give the classical trihydride OsH3(acac)(PiPr3)2 (3). The protonation of 3 with triflic acid (HOTf) produces the release of H2 and the formation of the unsaturated osmium(IV) dihydride [OsH2(acac)(PiPr3)2]OTf (4), which is also prepared by starting from 2 via the intermediate OsH2Cl(acac)(PiPr3)2 (5). Treatment of an acetylacetone solution of 5 with KOH affords Os(acac)2(PiPr3)2 (6). In the presence of 5 mol % of KOH, complexes 3-6 promote the coupling of benzyl alcohol and aniline to give N-benzylideneaniline and H2. Under the same conditions, complex 3 catalyzes a wide range of analogous couplings to afford a variety of imines, including aliphatic imines, with yields between 90 and 40% after 1-48 h. Complex 3 also catalyzes the dehydrogenation of cyclic amines. According to the amount of H2 released by each 1 g of employed substrate, the amines have been classified into three classes: poor (1,2,3,4-tetrahydroquinaldine, 2-methylindoline, and 2,6-dimethylpiperidine), moderate (1,2,3,4-tetrahydroquinoline and 6-methyl-1,2,3,4-tetrahydroquinoline), and good hydrogen donors (1,2,3,4-tetrahydroisoquinoline).
- Esteruelas, Miguel A.,Lezáun, Virginia,Martínez, Antonio,Oliván, Montserrat,Onate, Enrique
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p. 2996 - 3004
(2017/08/21)
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- A Route to Polysubstituted Aziridines from Carbenes and Imines through a Nondiazo Approach
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An efficient method for the synthesis of polysubstituted aziridines utilizing enynones and imines is described. This transformation is achieved through the reaction of imines with donor/donor carbene intermediates, which were generated in situ from the cyclization of enynones. Furthermore, the resulted aziridines were good 1,3-dipoles, which could be efficiently trapped by dipolarophiles to give five-membered heterocycles. The obvious advantages of wide substrate scopes, mild reaction conditions, and high atom efficiency make this system highly appealing for construction of polysubstituted aziridines, 2,5-dihydropyroles, and 1,2,4-triazolidines.
- Luo, Hejiang,Chen, Kai,Jiang, Huanfeng,Zhu, Shifa
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supporting information
p. 5208 - 5211
(2016/11/02)
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- A Solvent-Free Process for Synthesis of Imines by Iron-Catalyzed Oxidative Self- or Cross-Condensation of Primary Amines Using Molecular Oxygen as Sole Oxidant
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Abstract: The synthesis of imines by oxidative self- or cross-condensation of primary amines has been achieved using iron(II) bromide as the catalyst. The protocol is ligand-free, additive-free, solvent-free, and high-yielding and utilizes renewable oxygen as sole oxidant. The reaction tolerated a wide range of functionalities. Graphical Abstract: [Figure not available: see fulltext.]
- Gopalaiah, Kovuru,Saini, Anupama
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p. 1648 - 1654
(2016/08/30)
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- Load manganese oxidizing catalytic chipboard spreading method for one-step synthesis of imines
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The invention belongs to the technical fields of chemistry and chemical engineering, and concretely relates to a method for one step synthesis of imine through catalyzing alcohol and amine by supported manganese oxide. A reaction of alcohol and amine is carried out in a solvent or solvent-free state at 60-90DEG C for 6-48h with the supported manganese oxide as a catalyst and molecular oxygen or air as an antioxidant to realize one step synthesis of a corresponding imine compound. The valence of manganese in the catalyst is +2, +3 or +4, the general formula of the catalyst is MnOx, and a carrier is hydroxyapatite (Ca10(PO4)6(OH)2). The catalyst still has very good activity and selectivity after the catalyst is reused at least 9 times. The catalyst used in the method has the characteristics of simple preparation, cheapness, high reaction selectivity and environmental protection.
- -
-
Paragraph 0050; 0051
(2017/02/02)
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- Lanthanides Mediated Oxidative Cross Coupling of Benzylalcohol and Various Amines to Form Corresponding Imines
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Herein, a new and efficient approach towards the oxidative cross-coupling of benzylalcohol and various aromatic amines to form corresponding imines with high degree conversion (>80 %) and chemo-selectivity using lanthanide salts as pre-catalysts is presented. The catalyzed oxidative cross-coupling reaction using La(NO3)3·6H2O as pre-catalyst displayed a broad substrate scope. The reaction afforded various substituted imines from the reaction of benzylalcohol with ample variety of amines in good yields.
- Bhattacharjee, Jayeeta,Sachdeva, Mitali,Panda, Tarun K.
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supporting information
p. 937 - 940
(2016/09/03)
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- Imine compound preparation method
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The invention relates to an imine compound preparation method. The preparation method comprises that benzyl alcohol or its derivative and an amine compound as reaction substrates undergo an oxidative condensation reaction in the presence of a catalyst to produce the imine compound. The imine compound preparation method utilizes a metal oxide as a catalyst and comprises that benzyl alcohol or its derivative, an amine compound and the metal oxide are mixed, the mixture is put into a pressure container, the pressure container is sealed, the mixture undergoes a stirring reaction at a temperature of 30-150 DEG C for 1-24h and the reaction product is separated so that the imine compound is obtained. The preparation method has the advantages of easy separation of the product and the catalyst, recycle of the catalyst, simple and easy reaction processes and the highest imine compound yield of 99%.
- -
-
Paragraph 0071; 0072
(2017/03/08)
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- Base-catalyzed synthesis of amides and imines via C-C and CC bond cleavage
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A transition metal free base catalyzed approach for C-N bond formation via C-C and CC bond activation has been developed. The N-arylureas reacted smoothly with 1,3-dicarbonyls and α,β-unsaturated ketones to furnish the corresponding amides and imines respectively in moderate to excellent yields.
- Yadav, Dilip Kumar T.,Bhanage, Bhalchandra M.
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p. 12387 - 12391
(2015/02/19)
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- A ruthenium-based catalytic system for a mild borrowing-hydrogen process
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The alkylation of arylamines using stoichiometric amounts of aliphatic and benzylic alcohols in the presence of tBuOK was carried out at 55 °C using a low catalyst loading of [Ru(cod)-Cl2]n/PTA (1,3,5-triaza-7-phosphaadamantane). The overall borrowing-hydrogen process does not require a controlled nitrogen atmosphere, and it could also be carried out at room temperature using higher loading of base. A wide range of substrates can be used in this transformation, and it has a good tolerance of different substituents. This catalytic system proved also to be efficient for other hydrogen-transfer reactions such as a tandem oxidation/C-C coupling between 1-phenylethanol and primary alcohols.
- Jumde, Varsha R.,Gonsalvi, Luca,Guerriero, Antonella,Peruzzini, Maurizio,Taddei, Maurizio
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p. 1829 - 1833
(2015/05/27)
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- Redox properties of CeO2at low temperature: The direct synthesis of imines from alcohol and amine
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We disclosed the redox properties of CeO2 in organic reactions at low temperature of 303 K. CeO2 works as the most effective heterogeneous catalyst for imine formation from benzyl alcohol and aniline at 303 K among various metal oxides and showed more than 38-fold higher activity than other simple metal oxides. CeO2 is applicable to the reaction of various alcohols and amines and gives high yields (80-98%) and high selectivities (89- > 99%). Kinetic measurements, MS, and FTIR analyses demonstrated that the high activity of CeO2 is a result of reactive oxygen species at the redox sites on CeO2. This discovery can help to create a new field in metal oxide catalysis.
- Tamura, Masazumi,Tomishige, Keiichi
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supporting information
p. 864 - 867
(2015/03/05)
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- An investigation of the effects of CeO2 crystal planes on the aerobic oxidative synthesis of imines from alcohols and amines
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We herein report the effects of CeO2 crystal planes on the oxidative coupling of alcohols and amines to form imines. CeO2 exhibits significant catalytic activity under mild reaction conditions (60 °C) during the synthesis of 13 different imines, giving >89% conversions and >90% selectivities. The crystal planes of CeO2 greatly affect the catalytic performance. Among the crystal planes investigated (the (110), (100) and (111) planes), the (110) plane shows the strongest redox ability and thus the best catalytic activity, generating a 97% yield of the imine at 60 °C in 2 h, because it contains the highest concentration of oxygen vacancies.
- Zhang, Zhixin,Wang, Yehong,Wang, Min,Lü, Jianmin,Li, Lihua,Zhang, Zhe,Li, Mingrun,Jiang, Jingyang,Wang, Feng
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p. 1623 - 1630
(2015/09/15)
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- Solid base catalyzed highly efficient N-alkylation of amines with alcohols in a solvent-free system
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Different from any other catalytic systems containing transition metals and additives, sodium hydroxide itself was found to be a unique and effective catalyst for the solvent-free synthesis of the secondary amines via the N-alkylation of amines with alcohols. For the reaction of aniline with benzyl alcohol, 99.6 mol% conversion of aniline and 99.5% selectivity of the product were achieved under optimal conditions. Also, high conversion and selectivity could be acquired for the N-alkylations of various amines with alcohols, implying the universality of this methodology. Mechanistic studies revealed that this novel reaction most possibly proceeds with a base-catalyzed mechanism.
- Lu,Sun,Wei,Peng,Zhou,Xia
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- Base-mediated synthesis of imines and amines from N-phenylureas and alcohols
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A new base-mediated protocol has been developed for the synthesis of imines and amines from N-phenylureas and alcohols under normal air. From the synthetic point of view, the protocol can be considered as an efficient alternative to conventional methods for the synthesis of imines and amines in moderate to excellent yields.Georg Thieme Verlag Stuttgart. New York.
- Yadav, Dilip Kumar T.,Bhanage, Bhalchandra M.
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supporting information
p. 1611 - 1615
(2014/07/08)
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- NaF regulated aqueous phase synthesis of aromatic amides and imines catalyzed by Au/HT
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An Au/HT catalyst was found to be an efficient heterogeneous catalyst for the coupling reaction of aromatic alcohols and amines. The amides and imines can be selectively synthesized with up to 99% yield with or without the addition of NaF as the cocatalyst. This journal is the Partner Organisations 2014.
- Wang, Qianqian,Deng, Youquan,Shi, Feng
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p. 1710 - 1715
(2014/06/09)
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- Direct imine formation by oxidative coupling of alcohols and amines using supported manganese oxides under an air atmosphere
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Manganese oxides loaded on various supports have been prepared and studied for the direct imine formation by oxidative coupling of alcohols and amines. Among the catalysts, hydroxyapatite supported manganese oxides (MnO x/HAP) show the best activity and selectivity for this reaction in the absence of an additional base using air as the environmentally benign terminal oxidant. NH3-/CO2-TPD results show that the amphoteric properties of MnOx/HAP are crucial for this reaction to obtain a satisfactory yield. Various aromatic alcohols and amines are smoothly transformed into the corresponding imines in good to excellent yields. The catalyst is reusable and gives 98% yield of the product in all 9 reuse tests. Compared with the fresh catalyst, the XRD and SEM of the reactivated MnO x/HAP after nine reactions do not show any obvious change. This journal is the Partner Organisations 2014.
- Chen, Bo,Li, Jun,Dai, Wen,Wang, Lianyue,Gao, Shuang
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p. 3328 - 3334
(2014/06/10)
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- Dehydrogenation and oxidative coupling of alcohol and amines catalyzed by organosilicon-supported TiO2@PMHSIPN
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The catalytic dehydrogenation and tandem transformation of aromatic alcohols, including oxidative coupling of alcohols and amines, were achieved successfully using a catalytic amount of organosilicon-supported titania (TiO2@PMHSIPN), which enables the efficient synthesis of aromatic aldehydes, imines, and benzimidazoles in good to excellent yields. This journal is the Partner Organisations 2014.
- Wang, Hu,Zhang, Jin,Cui, Yu-Ming,Yang, Ke-Fang,Zheng, Zhan-Jiang,Xu, Li-Wen
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p. 34681 - 34686
(2014/11/08)
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