- Cross-linked polystyrene-TiCl4 complex as a reusable Lewis acid catalyst for solvent-free Knoevenagel condensations of 1,3-dicarbonyl compounds with aldehydes
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Cross-linked polystyrene copolymer beads with the average particle size in the range of (50–80 mesh size) were prepared by a new method, characterized and functionalized with titanium tetrachloride to afford the corresponding polystyrene?titanium tetrachloride complex in one step reaction and characterized by FT-IR, UV, TGA, DSC, XRD, SEM, BET. This polymer metal complex (PS/TiCl4) was used as a heterogeneous, recoverable, reusable Lewis acid for solvent-free Knoevenagel condensations of 1,3-diketones with aromatic aldehydes under green and mild conditions. The rate of reactions was found to decrease with an increasing percentage of crosslinking and the mesh size of the copolymer beads. This complex showed good stability and catalytic activity in the Knoevenagel reactions.
- Rahmatpour, Ali,Goodarzi, Niloofar
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- Facile construction of 4H-chromenes via Michael addition of phenols to benzylidene oxobutanoates and their successful conversion into pyranocoumarins
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An efficient and simple approach for the synthesis of functionalized 4H-chromenes has been developed via acid catalyzed Michael addition of phenols to benzylidene oxobutanoates. Preliminary mechanistic studies were conducted, suggesting that intermediate
- Priyanka,Sharma, Rajesh K.,Butcher, Ray J.,Katiyar, Diksha
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supporting information
p. 2347 - 2351
(2018/05/24)
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- Design, synthesis and spectroscopic and crystallographic characterisation of novel functionalized pyrazole derivatives: biological evaluation for their cytotoxic, angiogenic and antioxidant activities
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Abstract: The current study presents the synthesis of functionalized pyrazoles (18–29) through 3 + 2 annulation reaction of ethyl 2-(arylidene)-3-oxobutanoates (8–13) with phenylhydrazine hydrochlorides (14–17) in acetic acid under reflux conditions. Stru
- Dileep Kumar, Achutha,Bharath, Srinivasan,Dharmappa, Rekha N.,Naveen, Shivalingegowda,Lokanath, Neratur Krishnappagowda,Ajay Kumar, Kariyappa
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p. 5635 - 5652
(2018/04/30)
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- A balufen green industrial production method (by machine translation)
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The invention discloses a balufen green preparation method, which belongs to the technical field of drug synthesis. The method to the chlorobenzene as a starting material, by Knoevenagel condensation, alkali hydrolysis, sub-amide, alkali hydrolysis and Hofmann degradation 5 step reaction make the consistent with the clinical pharmaceutical balufen. Raw materials of this invention extremely easy, low cost, simple synthesis operation, are basically all aqueous reaction under the condition of, environmental pollution is very small, high yield, is a brand new industrial production balufen method. (by machine translation)
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Paragraph 0022
(2017/05/02)
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- Visible-light-promoted iminyl-radical formation from Acyl oximes: A unified approach to pyridines, quinolines, and phenanthridines
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A unified strategy involving visible-light-induced iminyl-radical formation has been established for the construction of pyridines, quinolines, and phenanthridines from acyl oximes. With fac-[Ir(ppy)3] as a photoredox catalyst, the acyl oximes were converted by 1 e- reduction into iminyl radical intermediates, which then underwent intramolecular homolytic aromatic substitution (HAS) to give the N-containing arenes. These reactions proceeded with a broad range of substrates at room temperature in high yield. This strategy of visible-light-induced iminyl-radical formation was successfully applied to a five-step concise synthesis of benzo[c]phenanthridine alkaloids.
- Jiang, Heng,An, Xiaode,Tong, Kun,Zheng, Tianyi,Zhang, Yan,Yu, Shouyun
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supporting information
p. 4055 - 4059
(2015/03/30)
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- Synthesis of arylidene propanedioic acids by Knoevenagel condensation for use in ceramic sols
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This paper is primarily concerned with the synthesis of arylidene propanedioic acids by Knoevenagel condensation. Generally organic bases pyridine and piperidine are used as catalyst in Knoevenagel condensation which are costly and health hazard. In this research work, Knoevenagel condensation of various aromatic aldehydes (benzaldehyde, salicylaldehyde and p-chlorobenzaldehyde) and active methylenes (malonic acid and ethyl acetoacetate) was carried out in the presence of amino acids (glycine, lysine, hippuric acid, methionine and leucine) as catalyst. Using salicylaldehyde gave coumarin-3-carboxylic acid, a solvent free synthesis. These products were isolated and purified and were characterized through melting points, TLC, IR, mass and 1H NMR. These acids are synthesized for eventual development of organically modified ceramic nano powders.
- Shafqat, Syed Salman,Khan, Misbahul Ain,Zulkharnain, Azham,Hamdan, Sinin,Henry Rigit, Andrew Ragai,Khan, Amir Azam
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p. 8463 - 8466
(2015/12/31)
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- Design and synthesis of 4-alkyl-2-amino(acetamino)-6-aryl-1,3-thiazine derivatives as influenza neuraminidase inhibitors
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With a convenient and economical method, two series of 1,3-thiazine derivatives 1 and 2 were synthesized, and their neuraminidase (NA) inhibitory activities were evaluated. The pharmacological results showed that most of the compounds have potent NA inhibitory activity. Especially, 1g exhibited the best activity against influenza virus A (H1N1) NA (IC50 = 29.06 μg/mL), and its crystal structure was determined by single-crystal X-ray diffraction. The preliminary biological assay indicated that 1,3-thiazine could be used as a core structure to design novel influenza NA inhibitors. Two series of novel 1,3-thiazine analogs were synthesized and their neuraminidase (NA) inhibitory activities were evaluated. Most of the compounds have potent NA inhibitory activity. Compound 1g exhibited the best activity against influenza virus A (H1N1) NA with an IC50 of 29.06 μg/mL, and its crystal structure was determined by single-crystal X-ray diffraction.
- Li, Wan,Xia, Lin,Hu, Aixi,Liu, Ailin,Peng, Junmei,Tan, Weiqing
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p. 635 - 644
(2013/09/24)
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- Organocatalytic knoevenagel condensations by means of carbamic acid ammonium salts
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The Knoevenagel condensation between an active methylene compound and an aromatic aldehyde with a carbamic acid ammonium salt used as an organocatalyst gave the desired Knoevenagel products in up to 98% yield. The reaction occurred at rt and in a short reaction time under solvent-free conditions. In addition, no extraction, wash, or chromatography steps were needed to obtain a high-purity Knoevenagel product.
- Mase, Nobuyuki,Horibe, Takuya
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supporting information
p. 1854 - 1857
(2013/06/04)
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- Enzyme catalytic promiscuity: The papain-catalyzed Knoevenagel reaction
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Papain as a sustainable and inexpensive biocatalyst was used for the first time to catalyze the Knoevenagel reactions in DMSO/water. A wide range of aromatic, hetero-aromatic and α,β-unsaturated aldehydes could react with less active methylene compounds acetylacetone and ethyl acetoacetate. The products were obtained in moderate to excellent yields with Z/E selectivities of up to 100:0. This case of biocatalytic promiscuity not only widens the application of papain to new chemical transformations, but also could be developed into a potentially valuable method for organic synthesis.
- Hu, Wen,Guan, Zhi,Deng, Xiang,He, Yan-Hong
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experimental part
p. 656 - 661
(2012/05/04)
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- A simple method for the preparation of functionalized trisubstituted alkenes and α,β,γ,δ-unsaturated carbonyl compounds by using natural amino acid l-tryptophan
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Primary natural amino acid l-tryptophan was used, for the first time, as a catalyst in Knoevenagel condensations of aliphatic, aromatic, hetero-aromatic and α,β-unsaturated aldehydes with less reactive acetylacetone and ethyl acetoacetate. The reactions were carried out at room temperature and gave good yields. It is a convenient entry for preparation of functionalized trisubstituted alkenes and α,β,γ,δ-unsaturated carbonyl compounds.
- Hu, Ying,He, Yan-Hong,Guan, Zhi
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scheme or table
p. 656 - 659
(2010/11/05)
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- Solvent-free NbCl5 catalyzed condensation of 1,3-dicarbonyl compounds and aldehydes: a facile synthesis of trisubstituted alkenes
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A simple preparation of trisubstituted alkenes by condensation of β-diketones or β-ketoesters with aldehydes in presence of NbCl5 as a Lewis acid catalyst in solvent-free conditions is described.
- Yadav,Bhunia, Dinesh C.,Singh, Vinay K.,Srihari
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experimental part
p. 2470 - 2473
(2009/08/09)
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- Neat reaction technology for the synthesis of novel 1,5-benzodiazepines
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A convenient, solvent-free, green approach is described for the synthesis of novel 1,5-benzodiazepines by the reaction of ethylacetoacetate, aldehyde, and o-phenylenediamine without any catalyst at pH 7. Copyright Taylor & Francis Group, LLC.
- Kidwai, Mazaahir,Mothsra, Poonam
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p. 817 - 824
(2007/10/03)
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- Pyrazolopyridine derivatives
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The invention relates to compound of the formula (I) or its salt, in which R1, R2, R3 and R4 are as defined in the description, their use of as medicament, the process for their preparation and use for the treatment of PDE-IV or TNF-α mediated diseases.
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Page/Page column 9
(2010/02/15)
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- Neat reaction technology: A green tool
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A solvent free approach for organic synthesis is described which involve microwave exposure of neat reactants. A variety of cyclization and condensation are carried out including the efficient one pot assembly of heterocyclic molecules from in situ genera
- Kidwai, Mazaahir,Mothsra, Poonam
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p. 2330 - 2336
(2007/10/03)
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- Synthesis, structure, and electrochemical characteristics of 4-aryl-2-carbamoylmethylthio-5-ethoxycarbonyl-1,4-dihydropyridine-3-carboxylic acid nitriles
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We have obtained 4-aryl-2-carbamoylmethylthio-5-ethoxycarbonyl-1,4- dihydropyridine-3-carboxylic acid nitriles by S-alkylation of the corresponding 2-thioxo-1,2,3,4-tetrahydropyridine-3-carboxylic acid nitrile by iodoacetamide or one-pot multicomponent synthesis methods: condensation of 2-arylidene-acetoacetic acid ethyl ester, 2-cyanothioacetamide, piperidine, and iodoacetamide; acetoacetic acid ethyl ester, 3-aryl-2-cyanothioacrylamide, piperidine, and iodoacetamide; acetoacetic acid ethyl ester, an aromatic aldehyde, 2-cyanothioacetamide, piperidine, and iodoacetamide. We have carried out a comparative analysis of the capability of 2-alkylthio-4-aryl-5- ethoxycarbonyl-1,4-dihydropyridine-3-carboxylic acid nitriles for electrochemical oxidation as a function of the electronic properties of the aryl substituent in the 4 position of the heterocycle and the 2-alkylthio substituent. X-ray diffraction data indicate the existence of a hydrogen bond between the C=O of the 2-carbamoylmethylthio substituent and the NH of the hydrogenated heterocycle, which explains the more facile oxidation of the studied compounds compared with 2-methylthio-substituted 1,4-dihydropyridines.
- Baumane,Krauze,Belyakov,Sile,Chernova,Griga,Duburs,Stradins
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p. 362 - 373
(2007/10/03)
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- Kinetics and mechanism of benzylamine additions to ethyl α-acetyl-β-phenylacrylates in acetonitrile
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Kinetic studies of the addition of benzylamines to a noncyclic dicarbonyl group activated olefin, ethyl α-acetyl-β-phenylacrylate (EAP), in acetonitrile at 25.0°C are reported. The rates are lower than those for the cyclic dicarbonyl group activated olefi
- Oh, Hyuck Keun,Kim, In Kon,Sung, Dae Dong,Lee, Ikchoon
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p. 1213 - 1216
(2007/10/03)
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- SYNTHESIS OF HETEROCYCLIC COMPOUNDS. XXXVI. PREPARATION OF ALKYL SUBSTITUTED PYRANCARBONITRLES.
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The cyclization of the ketonitriles obtained from the reaction of suitably substituted propenones with propanedinitrile leads to alkyl substituted 4H-pyrans.Some of the starting propenones had to be prepared by base promoted opening of an isoxazole ring in the presence of an aldehyde.An exception to the general synthesis is also reported.
- Soto, Jose L.,Seoane, Carlos,Martin, Nazario,Quinteiro, Margarita
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