- A double basic Sr-amino containing MOF as a highly stable heterogeneous catalyst
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A novel metal-organic framework (MOF) based on strontium alkaline-earth metal and 2-amino-1,4-benzenedicarboxylic acid (NH2-bdc) has been developed. This material is formed by a linear succession of face-sharing strontium polyhedra bridged by a
- Leo, Pedro,Orcajo, Gisela,Briones, David,Rodríguez-Diéguez, Antonio,Choquesillo-Lazarte, Duane,Calleja, Guillermo,Martínez, Fernando
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- Ammonium chloride catalyzed Knoevenagel condensation in PEG-400 as ecofriendly solvent
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A simple and selective green methodology has been successfully developed for Knoevenagel condensation in polyethylene glycol-400 using 10 mol % ammonium chloride as catalyst. The method is applicable to a wide range of aromatic, heteroaromatic and α,β-unsaturated aldehydes. The reactions have been found to be clean and free from the formation of the Michael adduct.
- Waghmare, Smita R.
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p. 849 - 855
(2021/09/28)
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- The Modified Clay as a New and Eco-Friendly Catalyst for the Knoevenagel Reaction
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Abstract: This work aims the synthesis of substituted alkenes via Knoevenagel condensation using the clay collected from the Agadir region and modified by KF as a heterogeneous catalyst (KF-modified clay). In this context, the influence of various paramet
- Bentahar, S.,Dbik, A.,Khomri, M. El,Lacherai, A.,Messaoudi, N. El,Sabour, A.,Taleb, M. Ait
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p. 1438 - 1444
(2020/10/29)
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- Selenotungstates incorporating organophosphonate ligands and metal ions: synthesis, characterization, magnetism and catalytic efficiency in the Knoevenagel condensation reaction
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Three sandwich-type TM-containing (TM = transition metal) organophosphonate-based polyoxotungstate clusters, [TM(H2O)4(SeW6O21)2{Co(OOCCH2NCH2PO3)2}3]12?(TM = Co, Ni), have been successfully synthesized, which are the first reported TM-containing organophosphonate-based selenotungstates. They were structurally characterized by PXRD analyses, IR spectroscopy, TGA analyses,etc. Magnetic measurements show that all three compounds exhibit antiferromagnetic interactions. Besides,Co1can be used as an efficient heterogeneous catalyst in the Knoevenagel condensation of benzaldehyde and ethyl cyanoacetate under mild conditions (60 °C), and exhibits satisfactory conversion (93%) and high selectivity (99%).
- Ban, Ran,He, Peipei,Kong, Hui,Ma, Pengtao,Niu, Jingyang,Wang, Jiawei,Wang, Jingping,Xu, Qiaofei,Yang, Zongfei
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supporting information
p. 7420 - 7425
(2020/06/21)
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- Magnetic core-shell dendritic mesoporous silica nanospheres anchored with diamine as an efficient and recyclable base catalyst
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In the present study, diamine-functionalized magnetic core-shell dendritic mesoporous silica nanospheres have been successfully synthesized by an oil-water biphasic stratification-coating strategy. The shape, size and morphology of the synthesized magnetic nanocatalyst could be characterized by various physicochemical techniques such as, field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). The characteristic information about the successful immobilization of various functionalities on the nanospheres could be obtained with the help of X-ray powder diffraction (XRD) patterns, Fourier transform-infrared spectroscopy (FT-IR), energy dispersive X-ray spectroscopy (EDX) and thermo-gravimetric analysis (TGA). The details about the magnetic behaviour and surface area of the nanocatalyst could be acquired by vibrating sample magnetometry (VSM) and BET surface analysis, respectively. The synthesized diamine-functionalized magnetic nanoparticles were then explored as a highly efficient catalyst for the Knoevenagel condensation and one-pot synthesis of polyhydroquinolines using aromatic/heteroaromatic aldehydes and aliphatic aldehydes with active methylene compounds under very mild conditions. The synthesized magnetic core-shell dendritic mesoporous silica nanospheres had large surface areas. This large surface area and pore volume could facilitate a proper interaction and penetration of the reactant molecules with the basic amine groups present on the dendritic mesoporous silica nanospheres. The supported nanocatalyst revealed no sign of leaching of the amine groups present inside the dendrimers and therefore, could be reused up to nine times without any noteworthy loss in catalytic activity.
- Surabhi,Shabir, Javaid,Gupta, Padmini,Sah, Digvijay,Mozumdar, Subho
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p. 21152 - 21166
(2020/12/31)
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- Oxidative Olefination of Benzylamine with an Active Methylene Compound Mediated by Hypervalent Iodine (III)
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Hypervalent iodine-mediated oxidative olefination of amines with an active methylene compound provides a rapid gateway towards the formation of electrophilic alkenes under mild reaction conditions in good to excellent yields. This is an efficient protocol for the preparation of substituted electrophilic alkenes.
- Rupanawar, Bapurao D.,Veetil, Sruthi M.,Suryavanshi, Gurunath
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p. 6232 - 6239
(2019/11/05)
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- Synthesis of multifunctional polymer containing Ni-Pd NPs via thiol-ene reaction for one-pot cascade reactions
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Recently, acid–base bifunctional catalysts have been considered due to their abilities, such as the simultaneous activation of electrophilic and nucleophilic species and their high importance in organic syntheses. However, the synthesis of acid–base catalysts is problematic due to the neutralization of acidic and basic groups. This work reports a facial approach to solve this problem via the synthesis of a novel bifunctional polymer using inexpensive materials and easy methods. In this way, at the first step, heterogeneous poly (styrene sulfonic acid-n-vinylimidazole) containing pentaerythritol tetra-(3-mercaptopropionate) (PETMP) and trimethylolpropane trimethacrylate (TMPTMA) cross-linkers were synthesized in the pores of a mesoporous silica structure using click reaction as a novel bifunctional acid–base catalyst. After that, Ni-Pd nanoparticles supported on poly (styrenesulfonic acid-n-vinylimidazole)/KIT-6 as a novel trifunctional heterogeneous acid–base-metal catalyst was prepared. The prepared catalysts were characterized by various techniques like FT-IR, TGA, ICP-AES, DRS-UV, TEM, FE-SEM, EDS-Mapping, and XRD. The synthesized catalysts were efficiently used as bifunctional/trifunctional catalysts for one-pot, deacetalization-Knoevenagel condensation and one-pot, three-step and a sequential reaction containing deacetalization-Knoevenagel condensation-reduction reaction. It is important to note that the synthesized catalyst showing high chemo-selectivity for the reduction of nitro group, alkenyl double bond and ester group in the presence of nitrile. Moreover, it was found that the different nanoparticles including Ni, Pd, and alloyed Ni-Pd showing different chemo-selectivity and catalytic activity in the reaction.
- Javad Kalbasi, Roozbeh,Mesgarsaravi, Niloofar,Gharibi, Reza
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- Molybdenum oxide nanoparticles as recyclable heterogeneous catalyst for synthesis of arylidene ethyl cyanoacetates
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This work reports an adapted route to the highly efficient synthesis of arylidene ethyl cyanoacetate derivatives in the presence of catalytic amounts of molybdenum oxide nanoparticles (MoO3 NPs) under green conditions at ambient temperature. From the reaction, a wide range of novel arylidene ethyl cyanoacetates was successfully synthesized with high yields from the Knoevenagel condensation reaction between various aryl aldehydes and ethyl cyanoacetate in the presence of MoO3 nanoparticles. The capability of catalyst to separate from the reaction mixture and then reuse is another advantage of this reaction. Furthermore, obtained products belong to analogous of organic compounds that have shown biological activity, and can be used pharmaceutics.
- Pourshojaei, Yaghoub,Eskandari, Khalil,Elhami, Elaheh,Asadipour, Ali
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p. 5965 - 5973
(2019/06/14)
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- Amino Acid Amide based Ionic Liquid as an Efficient Organo-Catalyst for Solvent-free Knoevenagel Condensation at Room Temperature
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Abstract: Ionic liquids of amino acid amide were synthesized and used as an efficient catalyst for solvent-free Knoevenagel condensation. Synthesized ionic liquids are an environmentally benign, inexpensive, metal free and plays the dual role of solvent as well as an efficient catalyst for Knoevenagel condensation. A wide range of aliphatic, aromatic and heteroaromatic aldehydes easily undergo condensation with malononitrile and ethyl cyanoacetate. The reaction proceeds at room temperature without using any organic solvent and is very fast with good to excellent yield. Additionally, the catalyst is easily separable and recyclable without loss of activity. Graphic Abstract: [Figure not available: see fulltext.].
- Burate, Pralhad A.,Javle, Balasaheb R.,Desale, Pranjal H.,Kinage, Anil K.
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p. 2368 - 2375
(2019/06/17)
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- The Knoevenagel condensation using quinine as an organocatalyst under solvent-free conditions
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The Knoevenagel condensation between active methylene compounds and aromatic carobonyl compounds has been developed using quinine as an organocatalyst to afford various electrophilic alkenes in excellent yields (up to 90%). In the presence of a catalytic amount of quinine (15 mol%), the reaction proceeded at room temperature (RT) under solvent-free conditions. In this green approach, the organocatalyst was recovered and recycled for up to four cycles without appreciable loss of activity.
- Jain, Kavita,Chaudhuri, Saikat,Pal, Kuntal,Das, Kalpataru
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supporting information
p. 1299 - 1304
(2019/01/21)
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- Hypervalent Iodine(III)-Catalyzed Epoxidation of β-Cyanostyrenes
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A convenient approach for the synthesis of β-cyanoepoxides is illustrated by iodine(III)-catalyzed epoxidation of electron-deficient β-cyanostyrenes, wherein the active catalytic iodine(III) species was generated in situ. The epoxidation of β-cyanostyrenes was performed using 10 molpercent PhI as precatalyst in the presence of 2.0 equivalents Oxone as an oxidant and 2.4 equivalents of TFA as an additive at room temperature under ultrasonic radiations. The β-cyanoepoxides were isolated in good to excellent yields in a short reaction time.
- Mangaonkar, Saeesh R.,Singh, Fateh V.
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p. 4473 - 4486
(2019/11/21)
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- A functionalized UiO-66 MOF for turn-on fluorescence sensing of superoxide in water and efficient catalysis for Knoevenagel condensation
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In the present work, a new MOF material of the UiO-family called Zr-UiO-66-NH-CH2-Py (1) has been obtained by the solvothermal technique and successfully characterized. The MOF structure was assembled with 2-((pyridin-4-ylmethyl) amino) terephthalic acid (H2BDC-NH-CH2-Py) as linker and Zr4+ ion. The activated form of 1 (called 1′) exhibits considerable thermal and chemical stability. Compound 1′ showed a very rapid and selective response for the fluorometric sensing of superoxide (O2·-) in aqueous medium even in the presence of the potentially competitive reactive oxygen species (ROS). The limit of detection value for O2·- sensing is 0.21 μM, which is comparable with those of the reported O2·- sensors. This is the first MOF based fluorescent sensor for the detection of O2·-. The response time of this MOF sensor for O2·- is very short (240 s). On the other hand, 1′ was employed as a solid heterogeneous catalyst for Knoevenagel condensation between benzaldehyde and ethyl cyanoacetate at 80 °C in ethanol resulting in a very high yield of the desired product. The effects of the esterified linker ((CH3)2BDC-NH-CH2-Py) and the corresponding metal salt (ZrCl4) on this catalytic reaction were examined separately. We have also tested the substrate scope elaborately for the catalytic reaction promoted by catalyst 1′.
- Das, Aniruddha,Anbu, Nagaraj,Sk, Mostakim,Dhakshinamoorthy, Amarajothi,Biswas, Shyam
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p. 17371 - 17380
(2019/12/02)
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- Hierarchically Pore Structure poly 2-(Dimethyl amino) ethyl methacrylate/Hi-ZSM-5: A Novel Acid–Base Bi-functional Catalyst as Heterogeneous Platform for a Tandem Reaction
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Abstract: A simple method is developed to prepare an efficient and low cost acid–base bifunctional catalyst by using poly 2-(dimethyl amino) ethyl methacrylate as a basic part and hierarchical ZSM-5 as an acidic part of the catalyst. Tandem reaction of deacetalization–Knoevenagel condensation was selected to evaluate the prepared catalyst and the outcomes were excellent. Graphical Abstract: [Figure not available: see fulltext.].
- Javad Kalbasi, Roozbeh,Khojastegi, Anahita
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p. 958 - 971
(2018/02/12)
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- Synthesis and characterization of sulfamic acid supported on Fe3O4 nanoparticles: A green, versatile and magnetically separable acidic catalyst for oxidation reactions and Knoevenagel condensation
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Sulfamic acid immobilized on diethylenetriamine functionalized Fe3O4 nanoparticles (SA-DETA-Fe3O4) was successfully prepared and characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), vibrating sample magnetometer (VSM), thermo gravimetric analysis (TGA), X-Ray diffraction (XRD) and scanning electron microscopy (SEM). The sulfamic acid was found as a magnetically separable and highly active catalyst for the oxidative coupling thiols, oxidation of sulfides. Furthermore, the SA-DETA-Fe3O4 showed the high catalytic activity in Knoevenagel condensation of aromatic aldehydes with active methylene compounds (malononitrile and ethyl cynoacetate). The nanosolid catalyst could be easily recovered by a simple magnetic separation and reused for many cycles without deterioration in catalytic activity.
- Shiri, Lotfi,Narimani, Hojatollah,Kazemi, Mosstafa
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- Layered double hydroxide anchored ionic liquids as amphiphilic heterogeneous catalysts for the Knoevenagel condensation reaction
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In recent years, great attention has been dedicated to the development of heterogeneous base catalysts providing a green and sustainable process in benign aqueous media. Herein, the ionic liquid modified layered double hydroxide (LDH) based catalysts of L
- Li, Tengfei,Zhang, Wei,Chen, Wei,Miras, Haralampos N.,Song, Yu-Fei
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supporting information
p. 3059 - 3067
(2018/03/06)
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- Covalently anchored tertiary amine functionalized ionic liquid on silica coated nano-Fe3O4 as a novel, efficient and magnetically recoverable catalyst for the unsymmetrical Hantzsch reaction and Knoevenagel condensation
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A novel magnetic nanoparticle supported basic ionic liquid was successfully prepared by covalently anchoring 1-(2′-piperidyl)ethyl-3-(3-propyltriethoxysilane)imidazolium chloride onto the surface of silica-coated Fe3O4 nanoparticles, and characterized by FT-IR, TEM, XRD, TGA, VSM and elemental analysis. The obtained supported ionic liquid was certified as a versatile and robust catalyst for the unsymmetrical Hantzsch reaction and Knoevenagel condensation under solvent-free conditions. Furthermore, the catalyst could be conveniently recovered by an external magnet and reused six times without significant loss of catalytic activity.
- Zhang, Qiang,Ma, Xiao-Ming,Wei, Huai-Xin,Zhao, Xin,Luo, Jun
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p. 53861 - 53870
(2017/12/05)
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- Synthesis and characterization of bromine source supported on magnetic Fe3O4 nanoparticles: A new, versatile and efficient magnetically separable catalyst for organic synthesis
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Tribenzylammonium tribromide supported onto magnetic nanoparticles (Br3-TBA-Fe3O4) as a bromine source was successfully synthesized and characterized using Fourier transform infrared spectroscopy, thermogravimetric analysis, X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy and vibrating sample magnetometry. The synthesized catalyst is shown to be a versatile and highly efficient heterogeneous catalyst for the Knoevenagel condensation and synthesis of 2,3-dihydroquinazolin-4(1H)-one and polyhydroquinoline derivatives. To the best of the authors' knowledge, this is the first report of the use of a bromine source immobilized on Fe3O4 nanoparticles as a magnetically separable catalyst for these reactions. The nanosolid catalyst can be magnetically recovered and reused readily several times without significant loss in catalytic efficiency.
- Shiri, Lotfi,Ghorbani-Choghamarani, Arash,Kazemi, Mosstafa
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- Magnetic Fe3O4 nanoparticles supported amine: a new, sustainable and environmentally benign catalyst for condensation reactions
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Abstract: Diethylenetriamine immobilized on magnetic Fe3O4 nanoparticles (DETA-Fe3O4) was successfully prepared as a new and well dispersed magnetically separable amine catalyst. The structure of the resulting catalyst was well characterized by a series of analysis techniques such as FT-IR, SEM, EDX, VSM, TGA and XRD. The catalytic activity of DETA-Fe3O4 was evaluated with Knoevenagel condensation of active methylene compounds with aromatic aldehydes. Interestingly, the cyclocondensation of anthranilamide and aldehydes were effectively catalyzed by DETA-Fe3O4 in water, and the desired products (2,3-dihydroquinazoline-4(1H)-ones) were afforded in admirable yields. Catalysis research under aqueous medium (water) also makes this synthetic protocol ideal and fascinating from the environmental point of view. The amine catalyst can be magnetically recovered after the reaction and can be reused many times without appreciable decrease in activity.
- Shiri, Lotfi,Kazemi, Mosstafa
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p. 4813 - 4832
(2017/07/22)
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- Synthesis and characterization of bromine source immobilized on diethylenetriamine-functionalized magnetic nanoparticles: A novel, versatile and highly efficient reusable catalyst for organic synthesis
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Bromine source immobilized on magnetic nanoparticles functionalized with diethylenetriamine was successfully synthesized and characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, vibrating sample magnetometry, thermogravimetric analysis and X-ray diffraction. The catalytic activity in the synthesis of 2,3-dihydroquinazoline-4(1H)-one and polyhydroquinoline derivatives and in Knoevenagel condensation was studied. The bromine catalyst can be magnetically recovered and reused several times without significant loss of its catalytic activity. All products were obtained in high to excellent yields.
- Shiri, Lotfi,Rahmati, Sadegh,Ramezani Nejad, Zahra,Kazemi, Mosstafa
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- Fine tuning of catalytic and sorption properties of metal-organic frameworks via in situ ligand exchange
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Metal-organic frameworks (MOFs) are gaining considerable attention not only because of their diverse structures but also due to their interesting properties and potential applications. However, fabrication of MOFs with desired structures and properties re
- Wang, Peng,Chen, Kai,Liu, Qing,Wang, Huai-Wei,Azam, Mohammad,Al-Resayes, Saud I.,Lu, Yi,Sun, Wei-Yin
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supporting information
p. 11425 - 11430
(2017/09/07)
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- Photoswitching storage of guest molecules in metal-organic framework for photoswitchable catalysis: Exceptional product, ultrahigh photocontrol, and photomodulated size selectivity
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MOF materials, as new catalysts, show high catalytic activity and size-, regio-, and stereo-selectivity. However, artificially controlling their catalytic process by convenient external stimulus such as light is still unexploited. Such photocontrol over an organic reaction may enable switchable catalytic activities and/or selectivities, consequently producing desired products from a pool of building blocks according to the order and type of stimuli applied. In this study, we present a novel MOF catalyst, which not only offers ultrahigh photocontrol with the on/off ratio as high as 407, but also displays disparate photomodulation in reaction kinetics towards various aldehyde substrates in light of their sizes, thus creating the first example of MOFs showing photoswitchable catalysis. The origin, as unveiled by photoswitching adsorption experiments and density functional theory calculations, is due to photoswitching storage of guest molecules in the metal-organic framework (MOF).
- Gong, Le Le,Yao, Wan Ting,Liu, Zhi Qiang,Zheng, An Min,Li, Jian Qiang,Feng, Xue Feng,Ma, Lu Fang,Yan, Chang Sheng,Luo, Ming Biao,Luo, Feng
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p. 7961 - 7967
(2017/07/13)
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- Synthesis, characterization and heterogeneous base catalysis of amino functionalized lanthanide metal-organic frameworks
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Lanthanide metal-organic frameworks (Ln-MOFs) are featured by their tolerance to water and dense structure. In this work, an amine-functionalized Ln-MOF was facilely synthesized by coordination of terbium with 2-aminoterephthalic acid under the condition of microwave irradiation. The crystal structure was characterized by single crystal X-ray diffraction, FT-IR, Raman, TG-DTA and XPS analysis. The basic catalytic activity of the NH2-Tb-MOF was evaluated for Knoevenagel condensation and Henry reactions. Apart from the high activity and 100% selectivity to the condensation product, the NH2-Tb-MOF catalyst could be easily recycled and reused owing to the high stability of the MOF framework formed by coordination of Tb3+ with carboxylic groups. Remarkably, the NH2-Tb-MOF exhibited size-selective catalysis to substrates. For the small-sized reactants, it displayed comparable activity to the homogeneous catalyst of aniline owing to the high dispersion of NH2? active sites and the low diffusion limits. However, in the same reaction system, extremely poor activity in Knoevenagel condensation and Henry reaction for the bulky substrate 4-(tert-butyl) benzaldehyde was observed due to the both effects of substitute and inhibition of diffusion into the micropores. Crystal structure analysis provided a mechanistic evidence that the heterogeneous base catalysis arose from the amino groups densely distributed inside the micropores.
- Huang, Jinping,Li, Chunmei,Tao, Lingling,Zhu, Huilin,Hu, Gang
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p. 853 - 860
(2017/06/27)
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- A simple, efficient and green procedure for knoevenagel condensation in hydroxy-functionalized ionic liquids
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An efficient and simple Knoevenagel condensation catalyzed by hydroxy-functionalized ionic liquids proceeded smoothly in high yields under ambient and solvent-free conditions. The condensation procedures of aryl aldehydes and 2,4-thiazolidinedione was involved in hydrogen bonding interactions between the hydroxy groups of the ILs and the carbonyl group of the aldehyde. The ionic liquids can be reused for five times without significant loss in activity.
- Liu, Yuting,Li, Rong,Xing, Yanjun
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p. 1385 - 1397
(2015/07/15)
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- Ultrasound-promoted knoevenagel condensation catalyzed by KF-clinoptilolite
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Potassium fluoride-clinoptilolite, which is prepared from commercially available and cheap starting materials, was used as an efficient and recyclable catalyst for Knoevenagel condensation of aromatic aldehydes with active methylene compounds under ultras
- Keipour, Hoda,Hosseini, Abolfazl,Khalilzadeh, Mohammad A.,Ollevier, Thierry
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p. 645 - 650
(2015/11/09)
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- Classical Keggin Intercalated into Layered Double Hydroxides: Facile Preparation and Catalytic Efficiency in Knoevenagel Condensation Reactions
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The family of polyoxometalate (POM) intercalated layered double hydroxide (LDH) composite materials has shown great promise for the design of functional materials with numerous applications. It is known that intercalation of the classical Keggin polyoxome
- Jia, Yueqing,Fang, Yanjun,Zhang, Yingkui,Miras, Haralampos N.,Song, Yu-Fei
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p. 14862 - 14870
(2015/10/20)
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- Tri-lacunary polyoxometalates of Na8H[PW9O 34] as heterogeneous Lewis base catalysts for Knoevenagel condensation, cyanosilylation and the synthesis of benzoxazole derivatives
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We reported for the first time the development of tri-lacunary polyoxometalates (POMs) of Na8H[A-PW9O34] ·7H2O and Na8H[B-PW9O 34]·19H2O (Na-A-PW9 and Na-B-PW 9) as highly selective and efficient heterogeneous Lewis base catalysts for Knoevenagel condensation, cyanosilylation of various aldehydes and ketones and the synthesis of benzoxazole derivatives at 25 C under mild conditions. Since both Na-A-PW9 and Na-B-PW9 display no characteristic porosity, it is proposed that the catalytic reactions proceed not only on the surface and interface, but also in the bulk phase. The catalysts can be easily recovered and reused for at least six times without obvious decrease of catalytic activities and the structures of the catalysts remain unchanged after recycling. The easy preparation, high efficiency, reusability of the heterogeneous catalysts of Na-A-PW9 and Na-B-PW9 exhibit great potential for further application.
- Zhao, Shen,Chen, Yang,Song, Yu-Fei
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p. 140 - 146
(2014/03/21)
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- One-pot tandem catalytic synthesis of α, β-unsaturated nitriles from alcohol with nitriles in aqueous phase
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Pd1-Au1 bimetal catalysts supported on basic layered double hydroxide (LDH) have been prepared conveniently with surface impregnation methods and structurally characterized by XRD, TEM and XPS. The nanoparticles were highly dispersed on LDH with an average size of 2.08 ± 0.3 nm and showed a strong cooperative effect between Au and Pd for the step of the alcohol oxidation. Moreover, the present hydrotalcite-supported bimetal catalysts can catalyze efficiently one-pot α-arylation reactions of nitriles with various alcohols in aqueous phase through tandem reactions. The bimetal catalyst has been extended for a broad substrate scope and recycled for at least 4 times.
- Chen, Chen,Yang, Hanmin,Chen, Jizhong,Zhang, Ran,Guo, Li,Gan, Huimei,Song, Baoning,Zhu, Wenwen,Hua, Li,Hou, Zhenshan
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- Aqueous DABCO, an efficient medium for rapid organocatalyzed Knoevenagel condensation and the Gewald reaction
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In the presence of water and 1,4-diazabicyclo[2.2.2]octane, several aldehydes and cyclic ketones underwent efficient Knoevenagel condensation with malononitrile and ethyl cyanoacetate to produce the respective α.β-unsaturated systems within fairly short time periods. As a result, high yields of conjugated products were easily obtained. Products could be engaged in a Gewald reaction, either stepwise or in situ, to produce efficiently their respective 2-aminothiophenes within 4-7 h. TUeBITAK.
- Abaee, Mohammad Saeed,Cheraghi, Somayeh
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p. 650 - 660
(2014/07/07)
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- A simple, efficient and green procedure for Knoevenagel condensation in water or under solvent-free conditions
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1,4-Diazabicyclo[2.2.2]octane was used as an efficient catalyst in the Knoevenagel condensation reaction of various kinds of aromatic/aliphatic/ heterocyclic/α,β-unsaturated aldehydes and ketones with active methylene compounds. This is a convenient and rapid method for Knoevenagel condensation, which affords the corresponding substituted electrophilic alkenes in excellent yields. The reaction condition is mild and the method is operationally simple. The products, only E-isomers were detected, did not need to be purified. The use of water as the reaction mediummakes the process environmentally benign. The catalysts can be recycled six times without activity loss.
- Yu, Ya-Qin,Wang, Zhong-Liang
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p. 288 - 292
(2013/07/27)
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- Immobilization of L-Lysine on zeolite 4A as an organic-inorganic composite basic catalyst for synthesis of α,β-unsaturated carbonyl compounds under mild conditions
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Lysine (Lys) immobilized on zeolite 4A was prepared by a simple adsorption method. The physical and chemical properties of Lys/zeolite 4A were investigated by X-ray diffraction (XRD), FT-IR, Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM)
- Zamani, Farzad,Rezapour, Mehdi,Kianpour, Sahar
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p. 2367 - 2374
(2013/09/24)
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- Efficient protocol for knoevenagel condensation in presence of the diazabicyclo[5.4.0]undec-7-ene-water complex
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A simple and efficient protocol for Knoevenagel condensation has been developed in the presence of diazabicyclo[5.4.0]undec-7-ene (DBU)/water complex. A widely range of carbonyl compounds (aliphatic and aromatic aldehydes, ketones) could react smoothly with methylene active ingredients (malononitrile, ethyl cyanoacetate, diethyl malonate and acetylacetone), which can not proceed by conven- tional catalyst. Other significant features of this method include readily work-up, good recyclability of catalytic system and short reaction time.
- Ying, An-Guo,Wu, Cheng-Lin,He, Guang-Hong
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experimental part
p. 653 - 656
(2012/07/28)
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- Knoevenagel condensation of aldehydes with active methylene compounds catalyzed by MgC2O4/SiO2 under microwave irradiation and solvent-free conditions
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MgC2O4/SiO2 catalyzes the efficient Knoevenagel condensation of aldehydes with active methylene compounds in solvent-free conditions under microwave irradiation to give alkenes derivatives in excellent yields. MgC2/s
- Yuan, Shizhen,Li, Zhen,Xu, Ling
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experimental part
p. 393 - 402
(2012/05/20)
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- Tandem Knoevenagel-[3+2] cycloaddition-elimination reactions: One-pot synthesis of 4,5-disubstituted 1,2,3-(NH)-triazoles
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Sodium azide has been found to catalyse Knoevenagel condensation between aromatic aldehyde and cyano compound with active methylene hydrogens and this has led to a successful route for the one pot synthesis of 4,5-disubstituted 1,2,3-(NH)-triazoles from a
- Ponpandian, Thanasekaran,Muthusubramanian, Shanmugam
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experimental part
p. 59 - 63
(2012/01/05)
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- A highly negatively charged γ-Keggin germanodecatungstate efficient for Knoevenagel condensation
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A tetra-n-butylammonium (TBA) salt of a γ-Keggin -6-charged germanodecatungstate, [γ-H2GeW10O36] 6- (I), could act as an efficient homogeneous catalyst for Knoevenagel condensation of active methylene compounds with carbonyl compounds.
- Sugahara, Kosei,Kimura, Toshihiro,Kamata, Keigo,Yamaguchi, Kazuya,Mizuno, Noritaka
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supporting information
p. 8422 - 8424
(2012/10/29)
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- Critical assessment of the efficiency of chitosan biohydrogel beads as recyclable and heterogeneous organocatalyst for C-C bond formation
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The effectiveness of neutral pH chitosan hydrogel beads (CSHB) as a green organocatalyst for a variety of C-C bond forming reactions (i.e. aldol reaction, Knoevenagel condensation, nitroaldol (Henry) reaction, Michael addition) has been comprehensively evaluated. Reaction rates, conversions and selectivities were studied as a function of a series of input variables including size, pH and reactive surface area of the beads, catalyst loading, temperature, molecular weight of the biopolymer, concentration, solvent system and molar ratio of reactants. Moreover, the catalytic biohydrogel beads were characterized by a variety of techniques including, among others, SEM, FT-IR, TGA and DSC.
- Kuehbeck, Dennis,Saidulu,Reddy, K. Rajender,Diaz, David Diaz
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supporting information; experimental part
p. 378 - 392
(2012/04/10)
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- Silica grafted polyethylenimine as heterogeneous catalyst for condensation reactions
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Primary amine groups were attached to a silica surface by using α,ω-diamines derivatives and (3-glycidyloxypropyl)-trimethoxysilane activation. The same activation was used to graft polyethylenimine, which also contains secondary and tertiary amine groups. These silica aminated structures were tested as heterogeneous catalysts in nitroaldol condensation with nitromethane, the derivative with the polyethylenimine moiety being the more active catalyst. This catalyst also showed efficiency in the Knoevenagel condensation of benzaldehydes with ethyl cyanoacetate under very mild reaction conditions and showed much the same efficiency when used in consecutive reaction runs. A reaction mechanism with participation of the several amine groups of the catalysts is discussed.
- Ribeiro, Sonia M.,Serra, Arménio. C.,Gonsalves, A.M. D'A. Rocha
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experimental part
p. 126 - 133
(2012/02/01)
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- A simple, efficient, and green protocol for Knoevenagel condensation in a cost-effective ionic liquid 2-hydroxyethlammonium formate without a catalyst
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Knoevenagel condensation of aromatic aldehydes with active methylene compounds such as malononitrile, ethylcyanoacetate, and cyanoacetamide proceeded very smoothly in reusable and cheap ionic liquid 2-hydroxyethylammonium formate at room temperature in the absence of a catalyst. Compared to other reported ionic liquids, the ionic liquid 2-hydroxyethylammonium formate shows better potential in the applications on the industrial scale with its low cost and viscosity.
- Ying, Anguo,Liang, Huading,Zheng, Renhua,Ge, Changhua,Jiang, Huajiang,Wu, Chenglin
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experimental part
p. 579 - 585
(2012/05/05)
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- Controllable acid-base bifunctionalized mesoporous silica: Highly efficient catalyst for solvent-free Knoevenagel condensation reaction
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A controllable acid-base bifunctionalized mesoporous catalyst with acidic sites and basic sites in adjacent arrangements was prepared via an in situ cleavage of sulfonamide bond on synthetic process. During Knoevenagel condensation reaction of aromatic al
- Peng, Yin,Wang, Jianyao,Long, Jie,Liu, Guohua
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experimental part
p. 10 - 14
(2012/02/04)
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- Condensation of ethyl cyanoacetate with aromatic aldehydes in water, catalyzed by morpholine
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Synthesis of (E)-ethyl 2-cyano-3-phenylacrilate derivatives in water catalyzed by morpholine was investigated. The reactions were performed under green chemistry conditions. Copyright
- Gomes, Marcelo N.,De Oliveira, Cecilia M. A.,Garrote, Clevia F. D.,De Oliveira, Valeria,Menegatti, Ricardo
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experimental part
p. 52 - 57
(2011/03/19)
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- Microwave-assisted and efficient solvent-free Knoevenagel condensation. A sustainable protocol using porous calcium hydroxyapatite as catalyst
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A sustainable Knoevenagel condensation of a series of aldehydes with malononitrile and ethyl cyanoacetate is described. The process is based on the combination of microwave activation and hydroxyapatite catalysis under solvent-free conditions. Products ar
- Mallouk, Siham,Bougrin, Khalid,Laghzizil, Abdelaziz,Benhida, Rachid
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experimental part
p. 813 - 823
(2010/04/29)
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- Green and efficient Knoevenagel condensation catalysed by a DBU based ionic liquid in water
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An effi cient, clean and facile protocol for the Knoevenagel condensation of aromatic aldehydes with active methylene compounds catalysed by task specifi c ionic liquid 1,8-diazabicyclo[5.4.0]-undec-7-en-8-ium acetate in an aqueous medium has been developed. The reactions proceed at room temperature and high to excellent yields were afforded. The work-up procedure is very simple. The ionic liquid could be recycled for 10 runs without noticeably loss of its catalytic activity.
- Ying, An-Guo,Wang, Li-Min,Wang, Le-Le,Chen, Xin-Zhi,Ye, Wei-Dong
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experimental part
p. 30 - 33
(2010/05/19)
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- Imidazolium-based phosphinite ionic liquid (IL-OPPh2) as reusable catalyst and solvent for the knoevenagel condensation reaction
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A task-specific ionic liquid (IL, OPPh2) that bears a phosphinite weak Lewis base group in an imidazolium cation was found to efficiently catalyze the Knoevenagel condensation of arylaldehydes with malononitrile, dimethyl(diethyl)malonate, and
- Valizadeh, Hassan,Gholipour, Hamid
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experimental part
p. 1477 - 1485
(2010/07/09)
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- Efficient knoevenagel condensation catalyzed by 2-hydroxyethylammonium acetate under solvent-free conditions at room temperature
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An efficient method for Knoevenagel condensation of aromatic aldehydes with malononitrile or ethyl cyanoacetate has been developed using the inexpensive and environmentally friendly ionic liquid 2-hydroxyethylammonium acetate as catalyst. The reactions we
- Zhou, Zhongqiang,Yuan, Jiangyong,Yang, Rong
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experimental part
p. 2001 - 2007
(2009/10/24)
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- NITROGENATED HETEROCYCLIC COMPOUND AND PHARMACEUTICAL COMPOSITION COMPRISING THE SAME
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The present invention relates to novel compounds having a xanthine oxidase inhibitory effect and an uricosuric effect and pharmaceutical compositions comprising the same as an active ingredient. That is, the present invention relates nitrogen-containing heterocyclic compounds represented by the following general formula (I): wherein Y1 represents N or C(R4) ; Y2 represents N or C(R5) ; R4 and R5 independently represent an alkyl group, a hydrogen atom etc. ; one of R1 and R2 represents an optionally substituted aryl group, an alkoxygroup or an optionally substituted heterocyclic group; the other of R1 and R2 represents a haloalkyl group, a cyanogroup, ahalogenatometc.; and R3 represents a 5-tetrazolyl group or a carboxy group, and pharmaceutically acceptable salts thereof, and pharmaceutical compositions comprising the same as an active ingredient.
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Page/Page column 26
(2008/12/06)
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- The Knoevenagel reaction in water catalyzed by zwitterionic liquids
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Three hydroxyl functionalized zwitterionic liquids (ZILs) were found to be novel recyclable catalysts for the Knoevenagel condensation between aldehydes or ketones and active methylene compounds in aqueous medium. Both aldehydes and ketones gave satisfactory results. The products could simply be separated from the catalysts/water, and the catalysts could be recycled six times without noticeably decreasing the catalytic activity.
- Fang, Dong,Fei, Zheng-Hao,Liu, Zu-Liang
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experimental part
p. 799 - 803
(2009/09/28)
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- One-pot formation of functionalised 2-piperidinones from arylidenecyanoacetates and methanolic ammonia via tandem reactions
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Aryl aldehydes react with ethyl cyanoacetate in methanolic ammonium acetate to expeditiously furnish, besides high yields of arylidenecyanoacetates, 4,6-diaryl-3,5-dicyano-5-ethoxycarbonyl-2-piperidinonesinlow yields. But preformed arylidenecyanoacetates
- Chakrabarty, Manas,Karmakar, Sulakshana,Arima, Shiho,Harigaya, Yoshihiro
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experimental part
p. 795 - 804
(2009/09/25)
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- A straightforward method for the synthesis of functionalized trisubstituted alkenes through Na2S/Al2O3 catalyzed knoevenagel condensation
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Na2S/Al2O3 catalyzed the Knoevenagel condensation between an aldehyde and an active methylene compound to yield various trisubstituted alkenes.
- Heravi, Majid M.,Bakhtiari, Khadijeh,Taheri, Shima,Oskooie, Hossein A.
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p. 1557 - 1560
(2008/09/17)
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- Synthesis and binding affinities of methylvesamicol analogs for the acetylcholine transporter and sigma receptor
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We synthesized methylvesamicol analogs 13-16 and investigated the binding characteristics of 2-[4-phenylpiperidino]cyclohexanol (vesamicol) and methylvesamicol analogs 13-16, with a methyl group introduced into the 4-phenylpiperidine moiety, to sigma receptors (σ-1, σ-2) and to vesicular acetylcholine transporters (VAChT) in membranes of the rat brain and liver. In competitive inhibition studies, (-)-o-methylvesamicol [(-)-OMV] (13) (Ki = 6.7 nM), as well as (-)-vesamicol (Ki = 4.4 nM), had a high affinity for VAChT. (+)-p-Methylvesamicol [(+)-PMV] (16) (Ki = 3.0 nM), as well as SA4503 (Ki = 4.4 nM), reported as a σ-1 mapping agent for positron emission tomography (PET), had a high affinity for the σ-1 receptor. The binding affinity of (+)-PMV (16) for the σ-1 receptor (Ki = 3.0 nM) was about 13 times higher than that for the sigma-2 (σ-2) receptor (Ki = 40.7 nM). (+)-PMV (16) (K i = 199 nM) had a much lower affinity for VAChT than SA4503 (K i = 50.2 nM) and haloperidol (Ki = 41.4 nM). These results showed that the binding characteristics of (-)-OMV (13) to VAChT were similar to those of (-)-vesamicol and that (+)-PMV (16) bound to the σ-1 receptor with high affinity. In conclusion, (-)-OMV (13) and (+)-PMV (16), which had a suitable structure, with a methyl group for labeling with 11C, may become not only a new VAChT ligand and a new type of σ receptor ligand, respectively, but may also become a new target compound of VAChT and the σ-1 receptor radioligand for PET, respectively.
- Shiba, Kazuhiro,Ogawa, Kazuma,Ishiwata, Kiichi,Yajima, Kazuyoshi,Mori, Hirofumi
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p. 2620 - 2626
(2007/10/03)
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- Solvent-free L-proline catalysed condensation of ethyl cyanoacetate with aldehydes
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Solvent-free Knoevenagel condensation of ethyl cyanoacetate with aromatic aldehydes, catalysed by environmentally friendly silica gel supported L-proline under microwave irradiation is studied.
- Oskooie, Hossein A.,Roomizadeh, Elham,Heravi, Majid M.
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p. 246 - 247
(2007/10/03)
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