- Control of degradation reactions during radical functionalization of polypropylene in the melt
-
Isotactic polypropylene (iPP) gives very extensive degradation when treated with peroxides above its melting temperature in mechanical mixers or extruders. This undesired reaction is very modestly affected by maleate molecules which on the contrary actively compete with side reactions of macroradicals in the case of ethylene polymers. In this work iPP was treated in a Brabender mixer at 180°C with peroxide and different selected molecules capable of promptly reacting with the macroradical formed on iPP chain and converting it into a more stable free radical. Furan derivatives, successfully used for iPP cross-linking without any remarkable increase of MFR, were used as free radical removers and maleic anhydride as functionalizing monomer. The results indicate a detectable improvement with respect to the use of maleic monomers and peroxide only, allowing to us get a significant grafting of functional groups and only partial degradation. Moreover, furan derivatives bearing various reactive substituents were used as functionalizing molecules. The results are discussed in the frame of the general mechanism proposed for the free radical functionalization of polyolefin in the melt.
- Coiai, Serena,Passaglia, Elisa,Aglietto, Mauro,Ciardelli, Francesco
-
-
Read Online
- Ammonium chloride catalyzed Knoevenagel condensation in PEG-400 as ecofriendly solvent
-
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.
-
p. 849 - 855
(2021/09/28)
-
- 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
-
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
-
-
- Johnson-Corey-Chaykovsky fluorocyclopropanation of double activated alkenes: Scope and limitations
-
Johnson-Corey-Chaykovsky fluorocyclopropanation of double activated alkenes utilizing S-monofluoromethyl-S-phenyl-2,3,4,5-tetramethylphenylsulfonium tetrafluoroborate is an efficient approach to obtain a range of monofluorocyclopropane derivatives. So far, fluoromethylsulfonium salts have displayed the broadest scope for direct fluoromethylene transfer. In contrast to more commonly used fluorohalomethanes or freon derivatives, diarylfluoromethylsulfonium salts are bench stable, easy-to use reagents useful for the direct transfer of a fluoromethylene group to alkenes giving access to the challenging products-fluorocyclopropane derivatives. Interplay between the reactivity of the starting materials and stability of the fluorocyclopropanes formed determines the outcome of the process.
- Kazia, Armands,Melngaile, Renate,Mishnev, Anatoly,Veliks, Janis
-
supporting information
p. 1384 - 1388
(2020/03/03)
-
- Oxidative Olefination of Benzylamine with an Active Methylene Compound Mediated by Hypervalent Iodine (III)
-
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
-
p. 6232 - 6239
(2019/11/05)
-
- Amino Acid Amide based Ionic Liquid as an Efficient Organo-Catalyst for Solvent-free Knoevenagel Condensation at Room Temperature
-
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.
-
p. 2368 - 2375
(2019/06/17)
-
- Nmp-based ionic liquids: Recyclable catalysts for both hetero-Michael addition and Knoevenagel condensation in water
-
A series of novel N-methyl piperidine (Nmp)-based ionic liquids with 1,2-propanediol group are synthesized and used as catalysts for both hetero-Michael addition of α,β-unsaturated amides and Knoevenagel condensation at room temperature in water; and all the examined substrates could be transformed into corresponding products in good to excellent yields. Meanwhile IL-catalyzed hetero-Michael addition of α,β-unsaturated amides in water has not been reported in the previous literatures. Additionally, the catalyst is recyclable for the two reactions. This finding provides a green catalyst for both hetero-Michael addition of α,β-unsaturated amides and Knoevenagel condensation in water.
- Yang, Pengkun,Liu, Yawei,Chai, Ling,Lai, Zhenzhen,Fang, Xiaomin,Liu, Baoying,Zhang, Wenkai,Lu, Minghua,Xu, Yuanqing,Xu, Hao
-
supporting information
p. 1060 - 1067
(2018/05/23)
-
- 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
-
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
-
p. 53861 - 53870
(2017/12/05)
-
- Knoevenagel condensation catalyzed by novel Nmm-based ionic liquids in water
-
A series of novel N-methyl morpholine (Nmm) based ionic liquids with 1,2-propanediol group were synthesized and used as catalysts for Knoevenagel condensation at room temperature in water. Under the effect of the catalyst, various aldehydes or aliphatic ketones could react with a wide range of activated methylene compounds well, including malononitrile, alkyl cyanoacetate, cyanoacetamide, β-diketone, barbituric acid, 2-arylacetonitrile and thiazolidinedione. Furthermore, most of the products could be separated just by filtrating and washing with water. Additionally, the catalyst is recyclable and applicable for the large-scale synthesis.
- Xu, Hao,Pan, Liyang,Fang, Xiaomin,Liu, Baoying,Zhang, Wenkai,Lu, Minghua,Xu, Yuanqing,Ding, Tao,Chang, Haibo
-
supporting information
p. 2360 - 2365
(2017/05/29)
-
- 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
-
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.
-
p. 2401 - 2405
(2017/10/31)
-
- Development of the First Two-Pore Domain Potassium Channel TWIK-Related K+ Channel 1-Selective Agonist Possessing in Vivo Antinociceptive Activity
-
The TWIK-related K+ channel, TREK-1, has recently emerged as an attractive therapeutic target for the development of a novel class of analgesic drugs, suggesting that activation of TREK-1 could result in pain inhibition. Here, we report the synthesis of a series of substituted acrylic acids (1-54) based on our previous work with caffeate esters. The analogues were evaluated for their ability to modulate TREK-1 channel by electrophysiology and for their in vivo antinociceptive activity (acetic acid-induced writhing and hot plate assays), leading to the identification of a series of novel molecules able to activate TREK-1 and displaying potent antinociceptive activity in vivo. Furyl analogue 36 is the most promising of the series.
- Vivier, Delphine,Soussia, Ismail Ben,Rodrigues, Nuno,Lolignier, Stéphane,Devilliers, Ma?ly,Chatelain, Franck C.,Prival, Laetitia,Chapuy, Eric,Bourdier, Geoffrey,Bennis, Khalil,Lesage, Florian,Eschalier, Alain,Busserolles, Jér?me,Ducki, Sylvie
-
p. 1076 - 1088
(2017/02/19)
-
- Photoswitching storage of guest molecules in metal-organic framework for photoswitchable catalysis: Exceptional product, ultrahigh photocontrol, and photomodulated size selectivity
-
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
-
p. 7961 - 7967
(2017/07/13)
-
- Green condensation reaction of aromatic aldehydes with active methylene compounds catalyzed by anion-exchange resin under ultrasound irradiation
-
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
-
p. 559 - 564
(2014/11/08)
-
- Ultrasound-promoted knoevenagel condensation catalyzed by KF-clinoptilolite
-
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
-
p. 645 - 650
(2015/11/09)
-
- One-pot synthesis of furfural derivatives from pentoses using solid acid and base catalysts
-
One-pot synthesis of (2-furanylmethylene)malononitrile, a Knoevenagel product of furfural with malononitrile, from xylose efficiently proceeded by combined use of acid Amberlyst-15 and acid-base Cr/hydrotalcites in 44% yield. Structural characterization was carried out using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy, and nitrogen adsorption measurements. The Lewis acidic properties of the highly active Cr/HT were investigated using the Meerwein-Ponndorf-Verley (MPV) reaction. It was confirmed that the prepared Cr/HT possessed the Lewis acid Cr2O 3 on the HT surface. Thus, combined use of the dispersed Lewis acid Cr2O3 and the Bronsted base HT facilitated the isomerization step of aldose into ketose and strongly promoted activity for the synthesis of furfural derivatives from aldoses through isomerization, dehydration and Knoevenagel condensation reactions in a one-pot manner. This journal is the Partner Organisations 2014.
- Shirotori, Mahiro,Nishimura, Shun,Ebitani, Kohki
-
p. 971 - 978
(2014/04/03)
-
- Ionic liquid coated sulfonated carbon/silica composites: Novel heterogeneous catalysts for organic syntheses in water
-
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.
-
p. 7461 - 7470
(2014/02/14)
-
- A simple, efficient and green procedure for Knoevenagel condensation in water or under solvent-free conditions
-
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
-
p. 288 - 292
(2013/07/27)
-
- Efficient and reusable amine-functionalized polyacrylonitrile fiber catalysts for Knoevenagel condensation in water
-
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
-
experimental part
p. 2234 - 2242
(2012/09/10)
-
- Sodium benzoate as a green, efficient, and recyclable catalyst for knoevenagel condensation
-
Sodium benzoate was utilized as a novel efficient and green catalyst for the Knoevenagel condensation of aldehydes with active methylene compounds such as ethyl cyanoacetate and malononitrile to afford substituted olefins through the conventional stirring
- Liu, Qing,Ai, Hong-Mei
-
experimental part
p. 3004 - 3010
(2012/07/27)
-
- Efficient protocol for knoevenagel condensation in presence of the diazabicyclo[5.4.0]undec-7-ene-water complex
-
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
-
experimental part
p. 653 - 656
(2012/07/28)
-
- 2-pyrrolidinecarboxylic acid ionic liquid catalyzed knoevenagel condensation
-
The pyrrolidinecarboxylic functionalized ionic liquid, 1-butyl-3- methylimidazolium-(S)-2-pyrrolidinecarboxylic acid salt ([bmim][Pro]), was prepared using an improved procedure. α,β-Unsaturated carbonyl compounds were selectively synthesized and high yie
- Song, Hongbing,Yu, Yinghao,Chen, Xuewei,Li, Xuehui,Xi, Hongxia
-
experimental part
p. 666 - 669
(2012/08/08)
-
- Knoevenagel condensation of aldehydes with active methylene compounds catalyzed by MgC2O4/SiO2 under microwave irradiation and solvent-free conditions
-
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
-
experimental part
p. 393 - 402
(2012/05/20)
-
- Critical assessment of the efficiency of chitosan biohydrogel beads as recyclable and heterogeneous organocatalyst for C-C bond formation
-
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
-
supporting information; experimental part
p. 378 - 392
(2012/04/10)
-
- Silica grafted polyethylenimine as heterogeneous catalyst for condensation reactions
-
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
-
experimental part
p. 126 - 133
(2012/02/01)
-
- Knoevenagel condensation catalyzed by sodium silicate under solvent-free conditions
-
Sodium silicate pentahydrate has been utilized as an efficient catalyst for the Knoevenagel condensation of aromatic aldehydes with active methylene compounds to afford substituted olefins in yields of 80.6%~98.9% under solvent-free conditions at room tem
- Liu, Qing,Han, Yinfeng
-
experimental part
p. 2033 - 2037
(2011/11/30)
-
- Knoevenagel condensation catalyzed by a tertiary-amine functionalized polyacrylonitrile fiber
-
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
-
experimental part
p. 1828 - 1836
(2011/09/16)
-
- Green and efficient Knoevenagel condensation catalysed by a DBU based ionic liquid in water
-
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
-
experimental part
p. 30 - 33
(2010/05/19)
-
- Microwave-assisted and efficient solvent-free Knoevenagel condensation. A sustainable protocol using porous calcium hydroxyapatite as catalyst
-
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
-
experimental part
p. 813 - 823
(2010/04/29)
-
- Leucoemeraldine-Base-Catalyzed Knoevenagel Condensation
-
A facile method for Knoevenagel condensation has been developed by using Leucoemeraldine base as catalyst to give substituted alkenes in excellent yields. The recycling of the solid catalyst was investigated.
- Zhang, Ai-Qin,Zhang, Ning,Hong, Sanguo,Zhang, Ming
-
experimental part
p. 3024 - 3030
(2009/12/01)
-
- First example of organocatalysis by polystyrene-supported PAMAM dendrimers: Highly efficient and reusable catalyst for knoevenagel condensations
-
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
-
supporting information; experimental part
p. 4763 - 4768
(2009/05/07)
-
- A simple, efficient and green procedure for the Knoevenagel condensation of aldehydes with N-methylpiperazine at room temperature under solvent-free conditions
-
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
-
p. 2103 - 2112
(2008/09/21)
-
- Solvent-free L-proline catalysed condensation of ethyl cyanoacetate with aldehydes
-
Solvent-free Knoevenagel condensation of ethyl cyanoacetate with aromatic aldehydes, catalysed by environmentally friendly silica gel supported L-proline under microwave irradiation is studied.
- Oskooie, Hossein A.,Roomizadeh, Elham,Heravi, Majid M.
-
p. 246 - 247
(2007/10/03)
-
- Layered double hydroxides-supported diisopropylamide: Synthesis, characterization and application in organic reactions
-
The layered double hydroxides-supported diisopropylamide (LDH-DA) catalyst is found to be an efficient and selective solid base for aldol, Knoevenagel, Henry, Michael, transesterification and epoxidation reactions under liquid phase conditions. LDH-DA is synthesized by the interaction of lithium diisopropylamide with LDH-NO3 (as-synthesized) and calcined LDH-NO3. The LDH-DA (Mg/Al, 3/1) and their precursors are well characterized by using various instrumental techniques such as FT-IR, TGA and DTA, powder XRD, solid state 27Al MAS NMR spectroscopy, SEM and XPS (ESCA).
- Kantam, M. Lakshmi,Ravindra,Reddy, Ch. Venkat,Sreedhar,Choudary
-
p. 569 - 578
(2007/10/03)
-
- Knoevenagel condensation catalyzed by 1,1,3,3-tetramethylguanidium lactate
-
Knoevenagel condensation between malononitrile or ethyl cyanoacetate and carbonyl compounds could be effectively promoted by 1,1,3,3-tetramethylguanidium lactate, a basic ionic liquid, under mild conditions. Good to high isolated yields could be obtained.
- Zhang, Jicheng,Jiang, Tao,Han, Buxing,Zhu, Anlian,Ma, Xiumin
-
p. 3305 - 3317
(2007/10/03)
-
- Novel, efficient, and green procedure for the Knoevenagel condensation catalyzed by diammonium hydrogen phosphate in water
-
Knoevenagel condensation of various aromatic and heteroaromatic aldehydes with active methylene compounds like methyl and ethyl cyanoacetate, malononitrile, and cyanoacetamide proceeds smoothly with stirring in water in the presence of 4 mol% of diammoniu
- Balalaie, Saeed,Bararjanian, Morteza,Hekmat, Shohreh,Salehi, Peyman
-
p. 2549 - 2557
(2007/10/03)
-
- Novel, efficient, and green procedure for the Knoevenagel condensation catalyzed by diammonium hydrogen phosphate in water
-
Knoevenagel condensation of various aromatic and heteroaromatic aldehydes with active methylene compounds such as methyl and ethyl cyanoacetate, malononitrile, and cyanoacetamide proceeds smoothly with stirring in water in the presence of 4 mol% of diammo
- Balalaie, Saeed,Bararjanian, Morteza,Hekmat, Shohreh,Salehi, Peyman
-
p. 3703 - 3711
(2007/10/03)
-
- Environmentally friendly one-pot synthesis of α-alkylated nitriles using hydrotalcite-supported metal species as multifunctional solid catalysts
-
A ruthenium-grafted hydrotalcite (Ru/HT) and hydrotalcite-supported palladium nanoparticles (Pdnano/ HT) are easily prepared by treating basic layered double hydroxide, hydrotalcite (HT, Mg6Al 2(OH)16CO3) with aqueous RuCl 3·n H2O and K2[PdCl4] solutions, respectively, using surface impregnation methods. Analysis by means of X-ray diffraction, and energydispersive X-ray, electron paramagnetic resonance, and X-ray absorption fine structure spectroscopies proves that a monomeric RuIV species is grafted onto the surface of the HT. Meanwhile, after reduction of a surface-isolated PdII species, highly dispersed Pd nanoclusters with a mean diameter of about 70 A is observed on the Pdnano/HT surface by transmission electron microscopy analysis. These hydrotalcite-supported metal catalysts can effectively promote α-alkylation reactions of various nitriles with primary alcohols or carbonyl compounds through tandem reactions consisting of metal-catalyzed oxidation and reduction, and an aldol reaction promoted by the base sites of the HT. In these catalytic α-alkylations, homogeneous bases are unnecessary and the only by-product is water. Additionally, these catalyst systems are applicable to one-pot syntheses of glutaronitrile derivatives.
- Motokura, Ken,Fujita, Noriaki,Mori, Kohsuke,Mizugaki, Tomoo,Ebitani, Kohki,Jitsukawa, Koichiro,Kaneda, Kiyotomi
-
p. 8228 - 8239
(2007/10/03)
-
- Synthesis and some transformations of 2-(3-amino-1-phenylpropyl)furan
-
A preparative method was developed for the synthesis of ethyl furfurylidenecyanoacetate. Its condensation with phenylmagnesium bromide gave ethyl α-cyano-β-(2-furyl)hydrocinnamate, the decarboxylation of which led to β-(2-furyl)hydrocinnamonitrile. Reduct
- Arutyunyan,Akopyan,Gevorgyan,Snkhchyan,Panosyan
-
p. 437 - 441
(2007/10/03)
-
- Organic reactions in ionic liquids: Ionic liquids ethylammonium nitrate promoted Knoevenagel condensation of aromatic aldehydes with active methylene compounds
-
The Knoevenagel condensation of aromatic aldehydes with active methylene compounds proceeded efficiently in a reusable ionic liquid, ethylammonium nitrate, at room temperature in the absence of any catalyst with high yields.
- Hu, Yi,Chen, Jue,Le, Zhang-Gao,Zheng, Qin-Guo
-
p. 739 - 744
(2007/10/03)
-
- High surface area MgO as a highly effective heterogeneous base catalyst for michael addition and knoevenagel condensation reactions
-
Magnesium oxide (MgO), obtained using a novel but simple procedure, was systematically investigated as a heterogeneous base catalyst for reactions taking place in the liquid phase, specifically the Michael addition and the Knoevenagel condensation. The ac
- Xu, Chunli,Bartley, Jonathan K.,Enache, Dan I.,Knight, David W.,Hutchings, Graham J.
-
p. 3468 - 3476
(2007/10/03)
-
- An eco-friendly synthesis of electrophilic alkenes catalyzed by dimethylaminopyridine under solvent-free conditions
-
Electrophilic olefins were synthesized in solvent-free condition using DMAP (10%mol) as catalyst in excellent yield and E-geometry. The various aldehydes which are aliphatic, aromatic, and heterocyclics underwent smoothly for Knoevenagel condensation with
- Narsaiah, A. Venkat,Basak,Visali,Nagaiah
-
p. 2893 - 2901
(2007/10/03)
-
- Phosphane-Catalyzed Knoevenagel Condensation: A Facile Synthesis of α-Cyanoacrylates and α-Cyanoacrylonitriles
-
Triphenylphosphane (TPP) has been utilized as a novel and efficient catalyst for the Knoevenagel condensation of aldehydes with acidic methylene compounds such as ethyl cyanoacetate and malononitrile to afford substituted olefins. The reaction proceeds smoothly under mild and solvent-free conditions and the products are obtained in excellent yields with an E-geometry. This method is applicable for a wide range of aldehydes including aromatic, aliphatic and heterocyclic substrates. Microwave irradiation has been used to achieve enhanced reaction rates and improved yields. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.
- Yadav, Jhillu S.,Subba Reddy, Basi V.,Basak, Ashok K.,Visali, Boddapati,Narsaiah, Akkirala Venkat,Nagaiah, Kommu
-
p. 546 - 551
(2007/10/03)
-
- ReBr(CO)5-catalyzed knoevenagel condensation
-
The Knoevenagel condensation procedure has been efficiently promoted by using a catalytic amount of ReBr(CO)5 to afford the corresponding dehydration coupling products in high yields.
- Zuo, Wei-Xiong,Hua, Ruimao,Qiu, Xianqing
-
p. 3219 - 3225
(2007/10/03)
-
- Organic Reactions in Ionic Liquids: Knoevenagel Condensation Catalyzed by Ethylenediammonium Diacetate
-
The moisture and air stable ionic liquids 1-butyl-3-methylimidazonium tetrafluoroborate [bmim]BF4 and 1-butyl-3-methylimidazonium hexafluorophosphate [bmim]PF6 were used as 'green' recycle alternatives to volatile organic solvents (VOCs) for ethylenediammonium diacetate (EDDA) catalyzed Knoevenagel condensation between aldehydes or ketones with active methylene compounds. Both aldehydes and ketones gave satisfactory results. The ionic liquids containing catalyst EDDA were recycled several times with no decrease in yields and reaction rates. In the case of 2-hydroxybenzaldehyde, the reactions led to the formation of 3-substituted coumarins under standard reaction conditions.
- Su, Ce,Chen, Zhen-Chu,Zheng, Qin-Guo
-
p. 555 - 559
(2007/10/03)
-
- Microwave-assisted Knoevenagel condensation of ethyl cyanoacetate with aldehydes in solvent-free condition
-
Piperazine has been used successfully as a catalyst for the Knoevenagel condensation of ethyl cyanoacetate and aromatic aldehydes along with the rate enhancement by microwave irradiation under solvent-free condition.
- Mitra, Alok Kumar,Banerjee, Sajal Kumar,Chattopadhyay, Sarmishtha
-
p. 921 - 922
(2007/10/03)
-
- Knoevenagel condensation in the heterogeneous phase using KF-montmorillonite as a new catalyst
-
The Knoevenagel condensation of aromatic aldehydes was carried out in DMF as solvent on KF-Montmorillonite catalyst, using malononitrile and ethyl cyanoacetate as the acidic methylene reagents. Only the e isomers of the products were obtained and confirme
- Shi, Da-qing,Wang, Xiang-shan,Yao, Chang-sheng,Mu, Lailong
-
p. 344 - 345
(2007/10/03)
-
- Regioselective synthesis of a new class of N-arylsulfonylaminated biheterocycles
-
A novel and efficient method for the synthesis of a new variety of novel N-arylsulfonylamino derivatives of biheterocycles by the reaction of N-cyanoaceto-arylsulphonylhydrazides with α,β-unsaturated nitriles. The synthetic potential of the method is demonstrated.
- Elgemeie, Galal Hamza,Sayed, Shahinaz Hassan
-
p. 587 - 592
(2007/10/03)
-
- An efficient benzyltriethylammonium chloride catalysed preparation of electrophilic alkenes: a practical synthesis of trimethoprim
-
The Knoevenagel condensation of carbonyl compounds with active methylene compounds was readily carried out with benzyltriethylammonium chloride as a catalytic agent, under solvent-free conditions to produce olefinic products in high yeilds: the scope of this protocol is utilised for the synthesis of the antibacterial agent trimethoprim.
- Bose, D. Subhas,Narsaiah, A. Venkat
-
-
- Potassium phosphate as a catalyst for the Knoevenagel condensation
-
The Knoevenagel condensation of carbonyl compounds with active methylene compounds proceeds smoothly in presence of potassium phosphate in commercial absolute ethanol to afford the desired products of good purity in moderate to excellent yields.
- Li
-
p. 524 - 525
(2007/10/03)
-