6906-25-8Relevant academic research and scientific papers
Rhodium catalyzed multicomponent dehydrogenative annulation: one-step construction of isoindole derivatives
Cheng, Biao,Lyu, Hairong,Quan, Yangjian,Xie, Zuowei
supporting information, p. 7930 - 7933 (2021/08/17)
A strategy for one-pot synthesis of isoindoles is describedviaa catalytic multicomponent dehydrogenative annulation of diarylimines, vinyl ketones and simple amines. In the presence of a rhodium catalyst and Cu oxidant, four C-H and two N-H bonds are activated along with the formation of one new C-C and two new C-N bonds, leading to a series of isoindole derivatives in good to very high isolated yields.
Highly chemoselective synthesis of imine over Co/Zn bimetallic MOFs derived Co3ZnC-ZnO embed in carbon nanosheet catalyst
Li, Guangming,Li, Jingfang,Li, Weizuo,Li, Xuewei,Mao, Guijie,She, Wei,Wang, Jing
, p. 17 - 26 (2021/07/28)
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.
Efficient Imine Formation by Oxidative Coupling at Low Temperature Catalyzed by High-Surface-Area Mesoporous CeO2 with Exceptional Redox Property
Wu, Shipeng,Wang, Yinghao,Cao, Qiue,Zhao, Qihua,Fang, Wenhao
supporting information, p. 3019 - 3028 (2020/12/11)
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.
Arene diruthenium(II)-mediated synthesis of imines from alcohols and amines under aerobic condition
Tamilthendral, Veerappan,Ramesh, Rengan,Malecki, Jan Grzegorz
, (2020/12/15)
The utility and selectivity of the newly synthesized dinuclear arene Ru(II) complex were demonstrated towards the synthesis of imines from coupling of alcohols and amines in the aerobic condition. Analytical and various spectral methods have been used to establish the unprecedented formation of the new thiolato-bridged dinuclear ruthenium complex. The molecular structure of the titled complex was evidenced with aid of X-ray crystallographic technique. A wide range of imines were obtained in good-to-excellent yields up to 98% and water as the by-product through an acceptorless dehydrogenative coupling of alcohols with amines. The catalytic reaction operated a concise atom economical without any oxidant with 1 mol% of the catalyst load. Further, the role of base, solvent and catalyst loading of the coupling reaction has been investigated. A plausible mechanism has been described and was found to proceed via the formation of an aldehyde intermediate. Short synthesis of antibacterial drug N-(salicylidene)-2-hydroxyaniline illustrated the utility of the present protocol.
Functional POM-catalyst for selective oxidative dehydrogenative couplings under aerobic conditions
Samaraj, Elavarasan,Balaraman, Ekambaram,Manickam, Sasidharan
, (2021/02/05)
Development of selective and efficient reusable catalytic systems for sustainable chemical production under benign conditions is attractive and received much attention. Herein, we report a rod-shaped octadecyl trimethylammonium functionalized Keggin-type polyoxometalate [PMO12O40] hybrids (OTA-POM) as an efficient heterogeneous catalyst for selective oxidative dehydrogenative couplings under aerobic conditions without any additive or external base. The catalyst recovery and subsequent five successive recyclability studies of hybrid POM confirms the heterogeneous nature of present catalytic system.
Efficient imine synthesisviaoxidative coupling of alcohols with amines in an air atmosphere using a mesoporous manganese-zirconium solid solution catalyst
Wu, Shipeng,Zhang, Hao,Cao, Qiue,Zhao, Qihua,Fang, Wenhao
, p. 810 - 822 (2021/02/26)
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.
One-pot imine synthesis from methylarenes and anilines under air over heterogeneous Cu oxide-modified CeO2catalyst
Tamura, Masazumi,Li, Yingai,Tomishige, Keiichi
supporting information, p. 7337 - 7340 (2020/07/23)
Cu oxide-modified CeO2 (CuOx-CeO2) with 2 wtpercent Cu loading amount was the most effective and reusable heterogeneous catalyst for selective one-pot imine synthesis from methylarenes and anilines via direct oxidation of the sp3 C-H bond in the methylare
Method for synthesizing imine by catalyzing alcohol-amine through NNN cobalt complex
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Paragraph 0074-0077, (2020/07/02)
The invention discloses a method for synthesizing imine by catalyzing alcohol-amine through an NNN cobalt complex. The method comprises the following steps: in a nitrogen atmosphere and at the temperature of 75-85 DEG C, taking an organic solvent as a solvent, taking an NNN cobalt complex (LCoCl2) as a catalyst under an alkaline condition, and reacting arylamine with aryl methanol for 40-55 hoursto obtain imine. The preparation method has the characteristics of high yield, few by-products, environmental friendliness and the like and has a wide application prospect.
Tuning effect of amorphous Fe2O3on Mn3O4for efficient atom-economic synthesis of imines at low temperature: Improving [O] transfer cycle of Mn3+/Mn2+in Mn3O4
Cao, Xiao,Gou, Galian,Long, Yu,Luo, Shicheng,Luo, Yutong,Ma, Jiantai,Qin, Jiaheng,Wang, Kaizhi,Wu, Wei
, p. 5628 - 5640 (2020/09/17)
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
Double and Single Hydroboration of Nitriles Catalyzed by a Ruthenium-Bis(silyl)xanthene Complex: Application to One-Pot Synthesis of Diarylamines and N-Arylimines
Kitano, Takeo,Komuro, Takashi,Tobita, Hiromi
supporting information, p. 1417 - 1420 (2019/03/19)
A ruthenium complex bearing a bis(silyl)xanthene chelate ligand xantsil, i.e. Ru[κ3(Si,O,Si)-xantsil](CO)(PCyp3) (1a, Cyp = cyclopentyl), was found to catalyze both double and single hydroboration reactions of nitriles with pinacolborane (HBpin) and 9-borabicyclo[3.3.1]nonane (9-BBN) to give bis(boryl)amines 2 and N-borylimines 3, respectively, in mostly >99% yields. By combination of these reactions with subsequent palladium-catalyzed deborylative C-N coupling reactions of 2 and 3 with a 1:1 mixture of bromoarenes and KOtBu, one-pot synthetic routes to tertiary N,N-diarylamines 4 and N-arylaldimines 5 from nitriles were developed.
