- Minimizing solvent waste in catalytic reactions in highly recyclable hydrocarbon solvents
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This paper describes chemistry using organocatalysts in hydrocarbon solvents that minimizes solvent waste by using inexpensive, non-volatile, relatively inflammable, and easily recyclable poly(α-olefin)s (PAOs) as hydrocarbon solvents. These studies show that when substrates have limited solubility in PAO solvents, this issue can be addressed by adding a small amount of a cosolvent. Kinetic studies were also carried out and show that reactions carried out in PAOs are kinetically comparable to reactions in conventional non-recyclable hydrocarbon solvents. A range of strategies that separate and isolate products from reactions in PAOs using a polyisobutylene (PIB)-supported DMAP catalyst have been studied using four different catalytic reactions. In the most general procedure, the PAO phase containing a PIB-bound catalyst is separated from products by low energy liquid/liquid gravity separation. This can be accomplished using a minimal amount of a polar solvent. In another example, the product's low solubility leads to it precipitating during the reaction. In this case, a simple filtration recycles the PAO and a PIB-bound DMAP catalyst. We have demonstrated that the PAO phase containing a PIB bound DMAP catalyst can be recycled for at least 10 cycles without loss of activity. Our studies further showed that leaching of the PAO phase into polar solvents was orders of magnitude less than conventional hydrocarbon solvents such as heptane. The result is that the overall solvent waste generation is lower than for the same reaction carried out in conventional solvents.
- Bergbreiter, David E.,Killough, James M.,Thavornpradit, Sopida
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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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- Silica bonded N-(propylcarbamoyl)sulfamic acid (SBPCSA) as a highly efficient and recyclable solid catalyst for the synthesis of Benzylidene Acrylate derivatives: Docking and reverse docking integrated approach of network pharmacology
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A green approach has been developed for the synthesis of a series of benzylidene acrylate 3(a-p) from differently substituted aromatic/heterocyclic aldehydes and ethyl cyanoacetate in excellent yields (90–98%), and employing silica bonded N-(Propylcarbamoyl)sulfamic acid as a recyclable catalyst under solvent-free condition. The molecular structure of compounds 3b, 3d and 3i were well supported by single-crystal X-ray crystallographic analysis. The present protocol bears wide substrate tolerance and is believed to be more practical, efficient, eco-friendly, and compatible as compared to existing methods. In-silico approaches were implemented to find the biochemical and physiological effects, toxicity, and biological profiles of the synthesized compounds to determine the expected biological nature and confirm a drug-like compound. A molecular docking study of the expected biologically active compound was performed to know the hypothetically binding mode with the receptor. Also, reverse docking is applied to recognize receptors from unknown protein targets for drug-like compounds to explain poly-pharmacology and binding postures with different receptors.
- Aslam, Afroz,Parveen, Mehtab,Alam, Mahboob,Silva, Manuela Ramos,Silva, P.S. Pereira
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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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- 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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- 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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- 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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- Microwave assisted urea-acetic acid catalyzed knoevenagel condensation of ethyl cyanoacetate and 1,3-Thiazolidine-2,4-dione with aromatic aldehydes under solvent free condition
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Knoevengel condensation reaction of various aromatic aldehydes with ethyl cyanoacetate and 1,3-thiazolidinone-2,4-diones catalyzed by urea-acetic acid under solvent free condition where olefinic products were obtained in high yield within short reaction time.
- Tryambake, Pravin. T.
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p. 2401 - 2405
(2017/10/31)
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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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- Synergistic NaBH4Reduction/Cyclization of 2-Aroylcyclopropane-1-carboxylates: Synthesis of 3-Oxabicyclo[3.1.0]hexane Derivatives
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An NaBH4reduction/cyclization reaction of readily available 2-aroyl-1-cyano-3-arylcyclopropane-1-carboxylate compounds was investigated. The process results in the stereoselective synthesis of 3-oxabicyclo[3.1.0]hexane derivatives in high yield
- Liu, Jiaming,Wang, Lizhong,Qing, Xushun,Zhang, Feixiang,Wang, Ting,Wang, Cunde
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supporting information
p. 1012 - 1018
(2017/02/15)
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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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- Fully-occupied Keggin type polyoxometalate as solid base for catalyzing CO2 cycloaddition and Knoevenagel condensation
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The highly negatively charged alkaline Keggin type polyoxometalate (POM) Na16[SiNb12O40]·xH2O (NaSiNb12) was synthesized and used as an efficient solid base catalyst for CO2 cycloaddition a
- Ge, Weilin,Wang, Xiaochen,Zhang, Lingyu,Du, Lei,Zhou, Yu,Wang, Jun
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p. 460 - 467
(2016/02/03)
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- Green condensation reaction of aromatic aldehydes with active methylene compounds catalyzed by anion-exchange resin under ultrasound irradiation
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To realize a practical and green chemistry, two important challenges need to be addressed, namely the effective process for the activation of reaction and efficient, eco-friendly and robust chemical methods for the reaction conversion to target products v
- Ammar, Hafedh Belhadj,Chtourou, Manef,Frikha, Mohamed Hédi,Trabelsi, Mahmoud
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p. 559 - 564
(2014/11/08)
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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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- A simple and efficient procedure for the Knoevenagel condensation catalyzed by [MeHMTA]BF4 ionic liquid
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Hexamethylenetetramine-based ionic liquid, 1-methylhexamethylenetetraminium tetrafluoroborate, has been used as a catalyst for a simple and efficient method for Knoevenagel condensation of active methylene compounds and various carbonyl compounds affordin
- Keithellakpam, Sanjoy,Moirangthem, Nimalini,Laitonjam, Warjeet S.
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p. 1157 - 1161
(2015/09/28)
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- Straightforward syntheses of nitriles, acrylates, and acrylamides in aqueous propan-1,2-diol: A catalyst free and waste free methodology
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A mild, elegant, catalyst free, and waste free methodology has been developed for the clear-cut synthesis of a diverse range of nitriles, acrylates, and acrylamides in good to excellent yields using aqueous propan-1,2-diol, a green reaction medium, at ambient temperature. Operational simplicity and recyclability of the reaction medium are added advantages of the methodology.
- Jayalakshmi, Lakshmi Narayanan,Karuppasamy, Ayyanar,Stalindurai, Kesavan,Sivaramakarthikeyan, Ramar,Devadoss, Vellasamy,Ramalingan, Chennan
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supporting information
p. 4207 - 4210
(2015/06/22)
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- Knoevenagel condensation reaction using ionic liquid [ADPQ][CF3SO3] as green and reusable catalyst
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Knoevenagel condensation reaction of aromatic aldehydes with some active methylene compounds proceeded efficiently without solvent using ionic liquids as catalyst. The experimental results show that these ionic liquids have good catalytic activities to th
- Gao, Xiaochong,Gao, Can,Gao, Ruichang
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p. 2145 - 2148
(2015/11/28)
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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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- Base-free Knoevenagel condensation catalyzed by copper metal surfaces
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For the first time Knoevenagel condensation has been catalyzed by elemental copper with unexpected activity and excellent isolated yields. Inexpensive, widely available copper powder was used to catalyze the condensation of cyanoacetate and benzaldehyde under mild conditions. To ensure general applicability, a wide variety of different substrates was successfully reacted.
- Schneider,Zeltner,Kr?nzlin,Grass,Stark
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supporting information
p. 10695 - 10698
(2015/06/30)
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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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- 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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- Graphene based material as a base catalyst for solvent free Aldol condensation and Knoevenagel reaction at room temperature
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Graphene oxide (GO) acts as a highly active heterogeneous base catalyst for a wide variety of reactions. Here we have described the catalytic activities of GO in the condensation reaction of various substituted benzaldehydes with acetophenone (aldol condensation) and with active methylene compound malononitrile (Knoevenagel reaction) at room temperature under solvent free condition. GO is characterized by powder X-ray diffraction (XRD), UV-visible spectra, Fourier transform infrared spectroscopy (FT-IR) and AFM. The experimental results showed that the GO had higher catalytic activity and it can be recycled without significant loss of its activity.
- Islam, Sk Manirul,Roy, Anupam Singha,Dey, Ram Chandra,Paul, Sumantra
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- Polystyrene-immobilized DABCO as a highly efficient and recyclable organocatalyst for the Knoevenagel condensation reaction
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Polystyrene-immobilized DABCO was used for the first time as a basic organocatalyst for carbon-carbon bond formation reactions. The supported catalyst could be used as a reusable catalyst in the Knoevenagel condensation of a wide range of aromatic/heterocyclic/α,β-unsaturated aldehydes and ketones with active methylene compounds. The reaction conditions are mild and the method is operationally simple. The reactions proceed in a short time period and with 100% selectivity. The catalyst could be easily separated from the reaction by filtration and recycled ten times without activity loss. Based on the catalyst, a continuous flow process was also developed.
- Xu, Da-Zhen,Shi, Sen,Wang, Yongmei
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p. 23075 - 23079
(2013/11/19)
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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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- 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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- Dolomite (CaMg(CO3)2) as a recyclable natural catalyst in Henry, Knoevenagel, and Michael reactions
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Iranian dolomite (CaMg(CO3)2) which consists of double-layered carbonates with Ca2+ and Mg2+ ions was utilized as a heterogeneous base catalyst in the CC, CN, and CS bond forming reactions via the Henry, Knoevenagel, aza-Michael, and thia-Michael transformations under mild conditions in water. Iranian dolomite has been characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Brunauer Emmett Teller (BET) and XRF chemical analysis, while its basic strength was evaluated by following the Hammett indicators procedure. This water-insoluble natural catalyst demonstrated high activity and was reusable.
- Tamaddon, Fatemeh,Tayefi, Mohammad,Hosseini, Elaheh,Zare, Elham
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- Organocatalytic knoevenagel condensations by means of carbamic acid ammonium salts
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The Knoevenagel condensation between an active methylene compound and an aromatic aldehyde with a carbamic acid ammonium salt used as an organocatalyst gave the desired Knoevenagel products in up to 98% yield. The reaction occurred at rt and in a short reaction time under solvent-free conditions. In addition, no extraction, wash, or chromatography steps were needed to obtain a high-purity Knoevenagel product.
- Mase, Nobuyuki,Horibe, Takuya
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supporting information
p. 1854 - 1857
(2013/06/04)
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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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- 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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- Microwave synthesis of α-cyano chalcones
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A novel methodology for facile production of α-cyano chalcones under microwave irradiation is described. Utilizing a Knoevenagel condensation between benzoylacetonitriles and aromatic aldehydes, substituted chalcones are generated via a 15-min, one-pot synthesis. Diversification of aromatic groups, including electron-withdrawing, electron-donating, and heterocyclic substitutions, has led to the isolation of over twenty colored, solid chalcone products. Furthermore the methodology can be extended to the synthesis of benzylidenemalononitriles as well as methyl and ethyl α-cyano cinnamates.
- Deshpande, Shyam J.,Leger, Paul R.,Sieck, Stephen R.
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supporting information; experimental part
p. 1772 - 1775
(2012/05/04)
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- Study on some hydroxyaryltellurium(IV) trichlorides catalyzed knoevenagel reactions
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Hydroxyaryltellurium trichlorides, R'TeCl3 (p-hydroxyphenyl and 3-methyl-4-hydroxyphenyl) have been prepared by condensation of tellurium tetrachloride with phenol or o-cresol respectively. These hydroxyaryltellurium trichlorides have been investigated as catalysts in Knoevenagel reactions between non-enolizable aldehydes and active methylene compounds to yield the corresponding olefinic products. This paper reports the reaction of ethylcyanoacetate,malononitrile and cyanoacetamide with aromatic aldehydes, ArCHO (Ar is C6H5, 4- ClC6H4, 4-CH3OC6H4 and C6H5-CH=CH). The products are obtained in excellent yield and high purity and have been identified by comparison of their properties with those of authentic samples.
- Garg, Sapana,Rimpi,Narwal, J. K.,Verma, K. K.
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p. 5619 - 5621,3
(2020/09/15)
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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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- First example of organocatalysis by polystyrene-supported PAMAM dendrimers: Highly efficient and reusable catalyst for knoevenagel condensations
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This paper describes the first use of polystyrene-supported poly(amidoamine) (PAMAM) dendrimers as heterogeneous basic organocatalysts for carbon-carbon bond formation. Polystyrene-supported PAMAM dendrimers of first, second and third generations have been used as reusable base catalysts in Knoevenagel condensations of carbonyl compounds with active methylene compounds. The reactions proceed in short periods of time and with 100% selectivity. This novel catalyst eliminates the use of aromatic and halogenated solvents, as well as complex purification processes. The catalysts can be recycled ten times. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
- Krishnan, G. Rajesh,Sreekumar, Krishnapillai
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supporting information; experimental part
p. 4763 - 4768
(2009/05/07)
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- A simple, efficient and green procedure for the Knoevenagel condensation of aldehydes with N-methylpiperazine at room temperature under solvent-free conditions
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Knoevenagel condensation of aromatic, aliphatic, and heteroaromatic aldehydes with active methylene compounds such as ethylcyanoacetate, malononitrile, and cyanoacetamide proceed very smoothly at room temperature by simply mixing the ingredients together under solvent-free conditions in the presence of N-methylpiperazine in excellent yields of the E-configured products. Copyright Taylor & Francis Group, LLC.
- Mukhopadhyay, Chhanda,Datta, Arup
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p. 2103 - 2112
(2008/09/21)
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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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- 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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