- Bromine-bromine interactions enhanced plasticity for the bending of a single crystal without affecting fluorescent properties
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Ethyl 3-(3-bromo-4-methoxy-phenyl)-2-cyano-acrylate crystals exhibited very superior plasticity and shape persistent, self-standing properties compared to their non-bromo analogue. The crystal plasticity, controlled by a bromine-bromine interaction, has b
- Paikar, Arpita,Podder, Debasish,Chowdhury, Srayoshi Roy,Sasmal, Supriya,Haldar, Debasish
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Read Online
- Synthesis of ionic liquid functionalized SBA-15 mesoporous materials as heterogeneous catalyst toward knoevenagel condensation under solvent-free conditions
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1-Methyl-3-propylimidazolium chloride (MPImCl) and 1-propylpyridinium chloride (PPyCl) ionic liquid functionalized SBA-15 mesoporous materials were synthesized and used as heterogeneous catalysts in Knoevenagel reactions with excellent yields and reusabil
- Liu, Yong,Peng, Jiajian,Zhai, Shangru,Li, Jiayun,Mao, Jianjiang,Li, Meijiang,Qiu, Huayu,Lai, Guoqiao
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Read Online
- A straightforward method for the synthesis of alkylidene and arylidene malonates through proline-catalyzed Knoevenagel condensation
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A straightforward method for the synthesis of alkylidene/arylidene malonates and arylidene cyanoacetates, utilizing proline as an alternative to traditional catalysts is presented. A large number of unsaturated esters was obtained from the Knoevenagel reaction under very mild conditions and utilizing cheap reagents.
- Cardillo, Giuliana,Fabbroni, Serena,Gentilucci, Luca,Gianotti, Massimo,Tolomeklli, Alessandra
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Read Online
- 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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- A facile, efficient and solvent-free titanium (IV) ethoxide catalysed knoevenagel condensation of aldehydes and active methylenes
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Titanium ethoxide has been employed as a novel and efficient reagent for the Knoevenagel condensation of aldehydes with active methylenes such as diethyl malonate and ethyl cyanoacetate under solvent free conditions to afford substituted olefins in high to excellent yields. The reaction is suitable for a variety of aromatic, aliphatic and heteroaromatic aldehydes with various active methylenes. Parallel to this, microwave irradiation has been utilized to achieve improved reaction rates and enhanced yields. Herein, we illustrated a convenient method for the preparation of α,β-unsaturated compounds using both conventional and microwave irradiation methods. An efficient and solvent free Knoevenagel condensation between aldehydes and active methylenes was developed using titanium ethoxide. The procedure proved to be successful with a wide range of substrates such as aromatic, aliphatic and heterocyclic aldehydes and various active methylenes to afford substituted olefins. The reaction was also carried out under microwave irradiation to accomplish the corresponding olefins with improved reaction rates, yields and cleaner reaction profiles.We have developed an efficient and novel methodology for the synthesis of olefinic compounds by Knoevenagel condensation under solvent-free conditions using titanium ethoxide, for the first time, as a reagent as well as a solvent. This method is appropriate for the synthesis of a variety of aromatic aldehydes containing various electron-donating and withdrawing groups, aliphatic and heteroaromatic aldehydes. The significant advantages offered by this methodology could be applied to various active methylenes in order to offer the corresponding Knoevenagel products. Thus, we believe that this method delivers high conversions, cleaner reaction profiles under solvent-free reaction conditions and shorter reaction times, all of which make it a very useful and attractive approach for the preparation of a wide range of substituted olefins.
- Ramaiah, Manjunatha M.,Shivananju, Nanjunda Swamy,Shubha, Priya Babu
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p. 107 - 115
(2020/02/04)
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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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- Bismuth (III) Triflate: A Mild, Efficient Promoter for the Synthesis of Trisubstituted Alkenes through Knoevenagel Condensation
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In this work, smooth efficient and eco-friendly two component coupling method is reported for the synthesis of Knoevenagel Condensation product in presence of Bi(OTf)3 catalyst under solvent free condition. Catalyst has participated in condensation between substituted aldehydes (aromatic and hetero-aromatic) and active methylene compounds (ethyl cyanoacetate, malononitrile and cyanoacetamide) effectively to generate an excellent yield of the product. Bi(OTf)3 catalyst is stable, inexpensive and easily available was used for four times in this reaction without loss of catalytic activity. [Formula Presented]
- Datta, Arup
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p. 843 - 849
(2020/11/25)
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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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- Water mediated procedure for preparation of stereoselective oximes as inhibitors of MRCK kinase
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Stereoselective aldoximes, preferably Z form have been obtained from α-cyano substituted carbonyl conjugated alkenes. This reaction occurs through Michael addition type reaction followed by retro-Knoevenagel reaction without transition-metal catalysis via C–C bond cleavage. These oximes are evaluated against cancer cell lines employing mechanistic study. Two oximes showed significant cytotoxic activity, which through in silico studies were found to inhibit MRCK Kinase, responsible for metastatic spread of cancer mortality.
- Luqman, Suaib,Misra, Krishna,Pandey, Jyoti,Shrivash, Manoj Kumar,Shukla, Akhilesh Kumar,Singh, Shilipi
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- Novel Application of Polymer Networks Carrying Tertiary Amines as a Catalyst Inside Microflow Reactors Used for Knoevenagel Reactions
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A novel application is described for utilizing hydrogel dots as organocatalyst carriers inside microfluidic reactors. Tertiary amines were covalently immobilized in the hydrogel dots. Due to the diffusion of reactants within the swollen hydrogel dots, the
- Appelhans, Dietmar,Berg, Patrik,Kuckling, Dirk,Obst, Franziska,Richter, Andreas,Simon, David
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p. 5765 - 5774
(2020/09/07)
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- Cascade reaction synthesis method of 2-(phenylmethylene)malononitrile or derivative thereof
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The invention discloses a cascade reaction synthesis method of 2-(phenylmethylene)malononitrile or a derivative thereof. According to the invention, a dendritic acid-alkali catalyst based on cross-linked polystyrene is synthesized, and 2-(phenylmethylene) malononitrile or a derivative thereof is synthesized in batches by successfully applying a cascade reaction into fluid chemistry, so that the method of the invention has advantages of substantially reduced, yield increase and no separation process of a catalyst and a product compared with the traditional test tube reaction.
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Paragraph 0048-0052
(2020/03/12)
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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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- 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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- 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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- Tandem synthesis method of 2-(phenylmethylene)malononitrile or derivative thereof
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A tandem synthesis method of 2-(phenylmethylene)malononitrile or a derivative thereof is disclosed. The general structural formula of the 2-(phenylmethylene)malononitrile or a derivative thereof is shown in the description, wherein R1 is hydrogen, p-methoxy, 2-bromo, 3-bromo or 4-bromo, and R2 is a cyano or ester group. A chloromethylated polystyrene microsphere acid-base functionalized catalyst is synthesized, a tandem reaction is successfully applied to the flow chemistry, and the 2-(phenylmethylene)malononitrile or a derivative thereof is synthesized in a gram scale. Compared with traditional test tube reactions, the method greatly reduces the reaction time, improves the yield and product purity, and avoids a step of separating a product from the catalyst.
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Paragraph 0044-0048
(2019/10/01)
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- Compartmentalization of Incompatible Polymers within Metal–Organic Frameworks towards Homogenization of Heterogeneous Hybrid Catalysts for Tandem Reactions
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New catalytic systems that contain incompatible catalytic sites were constructed by the in situ polymerization of acidic and basic polymers into metal–organic frameworks, which resulted in highly porous, recyclable, and durable catalytic composites with excellent compartmentalization, so that opposing agents were spatially isolated. These synthesized hybrid catalysts exhibited excellent catalytic activity for one-pot “wolf and lamb” reactions (deacetalization/Knoevenagel or Henry), which was attributed to their unique characteristic of having a locally homogeneous, but globally heterogeneous, structure.
- Zhao, Jin-Hao,Yang, Yong,Che, Jin-Xin,Zuo, Jun,Li, Xiao-Hua,Hu, Yong-Zhou,Dong, Xiao-Wu,Gao, Liang,Liu, Xin-Yuan
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supporting information
p. 9903 - 9909
(2018/07/25)
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- 6-MEMBERED CYCLIC AMINES OR LACTAMES SUBSTITUTED WITH UREA AND PHENYL
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The present invention relates to a compound according to general formula (I) which acts as a modulator of FPR2 and can be used in the treatment and/or prophylaxis of disorders which are at least partially mediated by FPR2.
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Paragraph 0321; 0323
(2018/04/13)
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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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- Cross-Linked Polyamine from Imidazolium-Based Materials: A Simple Route to Useful Catalytic Materials
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Cross-linked polyamine-based materials were easily prepared by reduction of the corresponding cross-linked imidazolium-based materials with sodium borohydride in hot ethanol. Overall, the synthetic procedure is based on the polymerization of a suitable bis-vinylimidazolium salt with or without a suitable support, such as silica or silica-coated magnetic nanoparticles (γ-Fe2O3@SiO2), followed by reduction. This simple approach allows the synthesis of materials based on a network of secondary and tertiary amines. Materials were characterized by 13C cross-polarization magic angle spinning NMR (13C CPMAS NMR), proton spin-lattice relaxation times in the rotating frame (T1ρH) and thermogravimetric analysis (TGA). Cross-linked polyamine-based materials were used as recoverable catalyst for Knoevenagel reaction. High yields of the condensation products were obtained and up to 11 cycles were carried out.
- Campisciano, Vincenzo,Salvo, Anna Maria Pia,Liotta, Leonarda Francesca,Spinella, Alberto,Giacalone, Francesco,Gruttadauria, Michelangelo
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p. 1352 - 1358
(2018/04/02)
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- Vanadium-Catalyzed Condensation of Ethyl Cyanoacetate with Ketones
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Vanadium compounds and complexes activated by pyridine or morpholine catalyze condensation of ethyl cyanoacetate with ketones and aldehydes leading to alkylidenecyanoacetates in 75–100% yield.
- Khusnutdinov,Shchadneva,Mayakova, Yu. Yu.
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p. 403 - 409
(2018/04/24)
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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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- 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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- Synthesis of 3-(4-fluorophenyl)-3-(4-methoxyphenyl)-1-propanarylamines and their antibacterial activity
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Condensation of 3-(4-fluorophenyl)-3-(4-methoxyphenyl)-1-propanamine with aromatic aldehydes and ketones followed by the reduction of the obtained azomethines with NaBH4 afforded secondary propanaryl -amines, whose oxalates and hydrochlorides p
- Arutyunyan,Akopyan,Akopyan,Stepanyan,Panosyan,Gevorgyan
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p. 1300 - 1304
(2017/08/08)
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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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- 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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- 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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- 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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- 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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- 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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- 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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- 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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- 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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- Ionic liquid coated sulfonated carbon/silica composites: Novel heterogeneous catalysts for organic syntheses in water
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Ionic liquid coated sulfonic acid functionalized amorphous carbon/silica composites derived from a starch-glucose mixture were developed and their catalytic activities were evaluated for Knoevenagel condensation, reductive amination of aldehydes and ketones, and for Michael addition of indole to α,β-unsaturated ketones in aqueous medium. The catalyst prepared from starch-glucose mixture (3:1) [CSC-Star-Glu-IL2] showed the highest activity in water. The catalysts were characterized by FTIR, TGA, elemental analysis, and the most active was further characterized by XRD, SEM and TEM.
- Gupta, Princy,Kour, Manmeet,Paul, Satya,Clark, James H.
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p. 7461 - 7470
(2014/02/14)
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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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- Reduced graphene oxide supported piperazine in aminocatalysis
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Reduced graphene oxide (rGO) has been used as a support for piperazine to provide a heterogeneous bifunctional organocatalyst (rGO-NH) that is able to efficiently promote vintage organic transformations such as Knoevenagel, Michael and aldol reactions. The obtained results suggest a significant role of the support in the course of these reactions. This journal is the Partner Organisations 2014.
- Rodrigo, Eduardo,García Alcubilla, Beatriz,Sainz, Raquel,Fierro, J. L. García,Ferritto, Rafael,Cid, M. Belén
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supporting information
p. 6270 - 6273
(2014/06/09)
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- Aminated poly(vinyl chloride): An efficient green catalyst for Knoevenagel condensation reactions
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Commercially available poly(vinyl chloride) have been modified with ethylene diamine to give a highly efficient reusable organocatalyst for Knoevenagel condensation in water as well as under solvent-less conditions. The reaction proceeds with high yield a
- Rajesh Krishnan,Sree Niveditha,Sreekumar
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p. 428 - 431
(2013/05/08)
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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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- 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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- 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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- Efficient and reusable amine-functionalized polyacrylonitrile fiber catalysts for Knoevenagel condensation in water
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A series of new fiber catalysts has been synthesized by aminating a commercially available polyacrylonitrile fiber with polyamines such as diethylenetriamine and triethylenetetramine. These fiber catalysts can efficiently catalyze the Knoevenagel condensation of benzaldehyde and ethyl cyanoacetate in water (yields: 95-98%). The triethylenetetramine aminated fiber catalyst was used to catalyze the condensations of a wide range of aromatic aldehydes and active methylene compounds and in each case, this catalyst performed well with yields higher than 93%. This fiber catalyst also exhibited excellent reusability (up to 21 times) and photostability.
- Li, Guowei,Xiao, Jia,Zhang, Wenqin
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experimental part
p. 2234 - 2242
(2012/09/10)
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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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- 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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- Knoevenagel condensation catalyzed by a tertiary-amine functionalized polyacrylonitrile fiber
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A new fiber catalyst for Knoevenagel condensation has been prepared by aminating a commercially available polyacrylonitrile fiber with N,N-dimethyl-1,3-propanediamine. The fiber catalyst was characterized by elemental analysis, X-ray powder diffraction spectra (XRD), scanning electron microscopy (SEM) and Fourier-transfer infrared spectroscopy (FTIR). The Knoevenagel condensation proceeded smoothly in the presence of the fiber catalyst and the products were obtained in excellent yields. This catalyst is applicable to a wide range of aromatic aldehydes. Moreover, the reaction can be easily carried out in different solvents of varying polarities. The newly developed fiber catalyst was also found to exhibit excellent recyclability and reusability (up to 10 times) without any additional treatment.
- Li, Guowei,Xiao, Jia,Zhang, Wenqin
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experimental part
p. 1828 - 1836
(2011/09/16)
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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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