- Bismuth(III) chloride as a New Catalyst for Knoevenagel Condensation in the Absence of Solvent
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The Knoevenagel condensation of various aldehydes was carried out under heterogeneous catalysts conditions using bismuth(III) chloride in absence of solvent.The method gives high yields of Knoevenagel products.
- Prajapati, Dipak,Sandhu, Jagir S.
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- Aminopropylated MCMs as base catalysts: A comparison with aminopropylated silica
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Aminopropyl-functionalised MCMs, prepared via a one-pot method, are found to be effective base catalysts for the Knoevenagel reaction, with significant improvements in terms of turnover number and solvent dependence to the ostensibly similar aminopropylsilica.
- Macquarrie, Duncan J.,Jackson, Dominic B.
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- Potassium triiodide. A new and efficient catalyst for carbon-carbon bond formation in aqueous media
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Potassium triiodide catalyses the condensation of carbonyl compounds with active methylene compounds in aqueous media to afford E olefinic products in high yields.
- Thakur, Ashim J.,Prajapati, Dipak,Gogoi, Baikuntha J.,Sandhu, Jagir S.
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- Functionalised ionic liquids: Synthesis of ionic liquids with tethered basic groups and their use in Heck and Knoevenagel reactions
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A simple and efficient synthesis of a novel series of ionic liquids bearing nucleophilic (Me2N) and non-nucleophilic base (iPr 2N) functionalities is described. The non-nucleophilic base functionality resembles the structure of the Huenig's base (N,N-diisopropylethylamine), which has been used widely in organic synthesis. A qualitative measure of the basicity of these ionic liquids is presented by utilising their interaction with universal indicator. The basicity of these ionic liquids was found to be dependent on the amine tether and choice of linker between the two nitrogen centres. The relative base strength of these ionic liquids was also probed by using them as catalysts in the Heck and Knoevenagel reactions. The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.
- Forsyth, Stewart A.,Froehlich, Ute,Goodrich, Peter,Gunaratne, H. Q. Nimal,Hardacre, Christopher,McKeown, Angela,Seddon, Kenneth R.
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- Nano-silica PAMAM dendrimer as a novel catalyst for Knoevenagel reactions
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A nano-silica dendrimer, poly(amidoamine)-grafted nanosilica (nano-PAMAM), catalyzed the Knoevenagel reaction of aryl and aliphatic aldehydes with various active methylene compounds at room temperature in good yields. The reaction conditions were mild eno
- Hagiwara, Hisahiro,Sekifuji, Masayoshi,Tsubokawa, Norio,Hoshi, Takashi,Suzuki, Toshio
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- N-Benzylidenebenzenesulfonamide as a benzaldehyde equivalent in the Knoevenagel reaction
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N-Benzylidenebenzenesulfonamide was shown to be a useful benzaldehyde equivalent in the Knoevenagel Reaction for cyana-containing active methylene compounds. The intermediate β-N-benzenesulfonylamino carbonyl derivatives from other active methylene compounds failed to undergo elimination.
- Zajac Jr.,Walters,Buzby,Gagnon,Labroli
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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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- Knoevenagel condensation of aromatic aldehydes with active methylene compounds catalyzed by lipoprotein lipase
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A screening of using different lipases to catalyze the Knoevenagel reaction was realized, and lipase lipoprotein (LPL) from Aspergillus niger showed the best catalytic performance. The reaction conditions including solvent, enzyme loading, and temperature were screened to improve the reaction efficiency. Various kinds of substrates were investigated, and almost all the target products were obtained in good to excellent yields (76-98%) with Z configuration exclusively. This procedure provides a novel, green and efficient method for the Knoevenagel condensation of aromatic aldehydes with active methylene compounds.
- Ding, Yan,Ni, Xiao,Gu, Mengjie,Li, Shuang,Huang, He,Hu, Yi
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p. 101 - 104
(2015/02/19)
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- One-pot multifunctional catalysis with NNN-Pincer Zr-MOF: Zr base catalyzed condensation with Rh-catalyzed hydrogenation
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We describe the postsynthetic modification of Zr-based metal organic frameworks (MOFs) containing chiral NNN-pincer ligands based on aminopyridineimines, as well as the subsequent formation of (NNN)-M-Zr-MOF complexes (M=Rh, Ir). With these new multifunct
- Rasero-Almansa, Antonia M.,Corma, Avelino,Iglesias, Marta,Sánchez, Félix
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p. 3092 - 3100
(2013/10/21)
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- Strong organic bases as building blocks of mesoporous hybrid catalysts for C-C forming bond reactions
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1,8-Bis(tetramethylguanidino)naphthalene (TMGN), a neutral organic base that combines the properties of guanidine and the properties of proton sponges, was used as a building block to produce organic-inorganic silica-based mesoporous hybrids with strong basic properties. The TMGN-based mesoporous hybrids (TMGN/SiO2) were prepared by a sol-gel route working at a neutral pH and low temperatures, which avoided the use of SDAs. TMGN has been modified in order to have two terminal reactive silyl groups able to perform co-condensation with a conventional organosilane (TMOS) used as a silicon source. This synthesis has allowed us to directly introduce the unmodified, functionalized TMGN as part of the walls of the mesoporous silica by a one-pot synthesis. TMGN/SiO2 hybrid materials present excellent catalytic properties for C-C bond forming reactions: Knoevenagel, Henry (nitroaldol), and Claisen-Schmidt condensations. The activity of the hybrid materials is higher than that of the counterpart homogeneous catalyst. The TMGN/SiO2 hybrid catalyst was synthesized using 1,8-bis(tetramethylguanidino)naphthalene (TMGN). It combines the properties of guanidine and of proton sponges. A functionalized TMGN builder was introduced directly into a nonordered mesoporous silica by the NH4F-catalyzed sol-gel route. This catalyst shows good catalytic performances in C-C bond forming reactions. Copyright
- Gianotti, Enrica,Diaz, Urbano,Velty, Alexandra,Corma, Avelino
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p. 5175 - 5185
(2013/01/15)
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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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- The use of electroosmotic flow as a pumping mechanism for semi-preparative scale continuous flow synthesis
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By employing a series of reactions we demonstrate the use of electroosmotic flow as a continuous pumping mechanism suitable for semi-preparative scale synthesis, affording an array of small organic compounds, of analytical purity, with yields ranging from 0.57-1.71 g h-1. The Royal Society of Chemistry.
- Wiles, Charlotte,Watts, Paul,Haswell, Stephen J.
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p. 966 - 968
(2007/12/31)
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- Unprecedented reaction between ethyl α-cyanocinnamate and o-phenylenediamine: Development of an efficient method for the transfer hydrogenation of electronically depleted olefins
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A reaction between ethyl α-cyanocinnamate and o-phenylenediamine under thermal conditions yielded 2-cyano-3-phenyl-propionic acid ethyl ester, 2-phenyl benzimidazole, and ethyl cyanoacetate. The mechanistic revelations led to the development of a simple and efficient transfer-hydrogenation process from the in situ generated benzimidazolines to activated olefins under solventless and catalyst-free conditions. Georg Thieme Verlag Stuttgart.
- Kumar, Satish,Kapoor, Kamal K.
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p. 2809 - 2814
(2008/02/13)
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- Polymeric sulfonate of piperazine as an inexpensive and recyclable catalyst for Knoevenagel condensation
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Polymeric sulfonate of piperazine (Amberlite 200 H/piperazine) has been found to be an inexpensive and reusable patalyst for Knoevenagel reaction between aldehydes and activated methylene compounds. The preparation and rejuvenation of the presented polyme
- Wen, Xinmin
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p. 762 - 765
(2007/10/03)
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- Dendritic nanoreactor encapsulating Rh complex catalyst for hydroformylation
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A Rh phosphine complex was encapsulated within the surface alkylated poly(propylene imine) dendrimers through ionic interactions. The resulting dendrimer complexes functioned as nanoreactors for hydroformylation of olefins. The congested surface of dendrimers with long alkyl chains favored hydroformylation of higher olefins. One-pot three reactions composed of hydroformylation, the Knoevenagel reaction, and hydrogenation proceeded within the dendritic nanoreactor. Copyright
- Mizugaki, Tomoo,Miyauchi, Yasuaki,Murata, Makoto,Ebitani, Kohki,Kaneda, Kiyotomi
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p. 286 - 287
(2007/10/03)
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- Use of a solid hydrotalcite structure incorporating fluorides for basic catalysis of michael or knoevenagel reactions
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The invention concerns the use of a solid basic catalyst comprising a hydrotalcite structure wherein part at least of the compensating anions are fluoride anions F? for producing Knoevenagel of Michael condensation reactions. The invention also concerns novel solid basic catalysts comprising a hydrotalcite structure characterised by a Mg/Al molar ratio ranging between 2.5 and 3.8 wherein at least part of the compensating anions are fluoride anions F?, and methods for preparing said novel catalysts.
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Page/Page column 5
(2008/06/13)
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- A simple approach for the synthesis of 2,6-diaryl-4-oxo-3,4- dihydropyrimidine-5-carbonitriles
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A concise, facile and straightforward synthesis of 2,6-diaryl-4-oxo-3,4- dihydropyrimidine-5-carbonitriles 12a-h is reported. The reaction for this preparation involves the condensation of ethyl α-cyanocinnamate and its para substituted analogs 8a-e with
- Mendonca Jr., Francisco J. B.,Dos Anjos, Janaina V.,Falcao, Emerson P. S.,De Melo, Sebastiao J.,Srivastava, Rajendra M.
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p. 479 - 484
(2007/10/03)
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- New P∧O ligand grafted on periodically organised mesoporous silicas for one-pot bifunctionnal catalysis: Coupling of base catalysed Knoevenagel condensation with in situ Rh catalysed hydrogenation
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The 1-phosphanorbornadiene-rhodium complex (Rh-PNBD) anchored on a mesostructured porous silica matrix is the first example of a rhodium center chelated by a phosphorus and an oxygen atom belonging to the anchoring siloxane moiety. These new hybrid silicas behave as very active recyclable hydrogenation catalysts, which combined with additional grafted amino functions allow efficiently driven one-pot bifunctionnal catalysis.
- Goettmann, Frederic,Grosso, David,Mercier, Francois,Mathey, Francois,Sanchez, Clement
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p. 1240 - 1241
(2007/10/03)
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- Liquid-phase Knoevenagel reactions over modified basic microporous titanosilicate ETS-10
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Al- and Ga-incorporated ETS-10, designated as ETAlS-10 and ETGaS-10, respectively, were synthesized by using P25 titania as a Ti source. The isomorphous substitution of Al and Ga for framework Si at the (4Si) environment was confirmed by 29Si M
- Goa, Yasuhide,Wu, Peng,Tatsumi, Takashi
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p. 107 - 114
(2007/10/03)
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- A novel multicomponent reaction involving isocyanide, dimethyl acetylenedicarboxylate (DMAD), and electrophilic styrenes: Facile synthesis of highly substituted cyclopentadienes
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Alkyl isocyanides, DMAD, and various activated styrenes furnish fully substituted cyclopentadienes in a one-pot three-component reaction.
- Nair, Vijay,Menon, Rajeev S.,Beneesh,Sreekumar,Bindu
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p. 767 - 769
(2007/10/03)
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- An Efficient Knoevenagel Condensation Catalyzed by LaCl3.7H 2O in Heterogeneous Medium
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Knoevenagel condensation was carried out in absence of solvent with a mild Lewis acid Lanthanum(III) chloride, to prepare substituted alkenes. A systematic study of the reaction to establish the generality of the method has been undertaken with various aldehydes and active methylene compounds.
- Narsaiah, A. Venkat,Nagaiah
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p. 3825 - 3832
(2007/10/03)
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- Microwave-enhanced Knoevenagel reaction catalyzed by calcium oxide
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Calcium oxide is employed both as heterogeneous catalyst and dehydrating agent in microwave-induced Knoevenagel reaction and gives the corresponding arylidene compounds in good yields.
- Peng, Yanqing,Song, Gonghua
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p. 924 - 926
(2007/10/03)
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- Knoevenagel condensation reaction in a membrane microreactor
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A multi-channel membrane microreactor was fabricated and tested for Knoevenagel condensation of benzaldehyde and ethyl cyanoacetate using Cs-exchanged faujasite NaX as the catalyst; the membrane microreactor achieves supra-eqiulibrium conversion at higher
- Lai, Sau Man,Martin-Aranda, Rosa,Yeung, King Lun
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p. 218 - 219
(2007/10/03)
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- An efficient Knoevenagel condensation using HZSM-5 zeolite as a catalyst
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Knoevenagel condensation is assisted by HZSM-5 zeolite wherein various aromatic aldehydes react readily with malononitrile and ethyl cyanoacetate to produce corresponding olefinic products.
- Heravi, Majid M.,Tajbakhsh, Mahmood,Mohajerani, Bagher,Ghassemzadeh, Mitra
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p. 857 - 858
(2007/10/03)
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- A synthetic entry into fused pyran derivatives through carbon transfer reactions of 1,3-oxazinanes and oxazolidines with carbon nucleophiles
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Acid catalysed condensations of various 2 substituted 1,3-oxazinanes 3 and 1,3-oxazolidines 4 with cyclic carbon nucleophiles viz. 5,5-dimethyl-1,3-cyclohexanedione and 1,3-cyclohexanedione furnish xanthene derivatives, whereas a Knoevenagel reaction proceeds with acyclic nucleophiles. In case of 4b and 4c, a unique synthesis of functionalised α-tetralones has emerged. Reactions of mixtures of cyclic and acyclic carbon nucleophiles with 3 provide some functionalised and partially reduced benzopyran derivatives.
- Singh, Kamaljit,Singh, Jasbir,Singh, Harjit
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p. 14273 - 14280
(2007/10/03)
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- Cadmium Iodide as a New Catalyst for Knoevenagel Condensations
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Cadmium iodide catalyses the condensation of aldehydes with active methylene compounds, in the absence of solvent, to afford olefinic products in high yields.
- Prajapati, Dipak,Sandhu, Jagir S.
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p. 739 - 740
(2007/10/02)
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- Utilisation of 13C N.M.R. Spectroscopy for the Identification of E- and Z-α,β-Unsaturated Esters, Ketones and Nitriles.
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Measurement of 3JCO,H coupling constants provides an unambiguous procedure for the configurational analysis of substituted 2- and 3-arylpropenoic esters and of E- and Z-2-arylbut-2-en-1,4-dioates, even when only one of the isomers is available for analysis.An analogous procedure can also be used for the configurational analysis of 3-arylpropenonitriles and of 4-arylbut-3-en-2-ones.
- Gregory, Barrie,Hinz, Werner,Jones, R. Alan,Arques, Jose Sepulveda
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p. 2801 - 2821
(2007/10/02)
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