- Ag–TiO2 nanocomposite-catalyzed one-pot synthesis of 1,2,4,5-tetrasubstituted imidazoles: a green and benign approach
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Ag–TiO2 nanocomposite as an efficient catalyst was synthesized and characterized by AFM analysis. This nanocomposite acts as a heterogeneous and recyclable catalyst for the room temperature synthesis of 1,2,4,5-tetrasubstituted imidazoles from aldehydes, benzil, ammonium acetate and several anilines or aliphatic amines via one-pot four-component condensation reaction in H2O as a green solvent. Ag–TiO2 nanocomposite was simply recovered by filtration and was reused up to three times.
- Alipour, Soghra,Vahdat, Seyed Mohammad,Chekin, Fereshteh
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p. 2315 - 2321
(2021/05/27)
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- Facile synthesis of imidazoles by an efficient and eco-friendly heterogeneous catalytic system constructed of Fe3O4 and Cu2O nanoparticles, and guarana as a natural basis
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In this study, an efficient hybrid nanocatalyst made of guar gum (guarana, as a natural basis), magnetic iron oxide nanoparticles, and copper(I) oxide nanoparticles (Cu2O NPs) is fabricated and suitably applied for catalyzing the multicomponent (three- and four-component) synthesis reactions of imidazole derivatives. Here, an easy preparation strategy for this novel catalytic system (Cu2O/Fe3O4@guarana) is presented. Then, the application of this catalytic system for the synthesis of imidazole derivatives is precisely investigated. For this purpose, ultrasonication is introduced as an efficient and fast method. In summary, the high catalytic efficiency of Cu2O/Fe3O4@guarana nanocomposite is well demonstrated by high reaction yields obtained in the presence of a small amount of this nanocomposite, under mild conditions. Wide active surface area, substantial magnetic behavior, excellent heterogeneity, suitable stability, well reusability, and etc. have distinguished this catalytic system as an instrumental tool for facilitating the complex synthetic reactions.
- Varzi, Zahra,Esmaeili, Mir Saeed,Taheri-Ledari, Reza,Maleki, Ali
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- Propyl–SO3H functionalized SBA-15: Microwave-mediated green synthesis of biologically active multi-substituted imidazole scaffolds
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Abstract: Propylsulfonic acid functionalized Santa Barbara Amorphous-15 (SBA-15–Pr–SO3H) catalyst has been synthesized using a surface modification of mesoporous SBA-15 via the one-pot co-condensation method. The synthesized SBA-15–Pr–SO3H has been characterized by peculiar characterization techniques such as small- and wide-angle XRD, SEM–EDX, TEM, TG–DTA, acidity, FT-IR, Py-FT-IR and BET surface area analysis. The catalytic activity of synthesized catalyst has been studied towards solvent-free MW irradiation for the green and rapid synthesis of multi-substituted imidazoles, [2,4,5-triphenyl-1(H)-imidazole (tri-imidazole) and 1-benzyl-2,4,5-triphenyl-1H-imidazole (tetra-imidazole)]. The SBA-15–Pr–SO3H catalyst was found to be an efficient and recyclable solid acid catalyst and this solvent-free MW protocol afforded products in good to excellent yields of both, tri and tetra imidazoles (> 95%) within shorter reaction time (3?min) at 600?W as compared to the SBA-15 and other existing protocols. The applicability of this protocol was further explored by conducting the experiments in the presence of varied solvents and substituted aldehydes to generate a library of both, tri- and tetra-imidazole scaffolds. The catalyst was found to be reusable up to several runs without loss of its catalytic activity. This report allows the rapid and scalable access to a variety of multi-substituted imidazoles using SBA-15–Pr–SO3H, as heterogeneous catalyst. Graphical abstract: SBA-15–Pr–SO3H catalyzed solvent-free MW assisted green synthesis of multi-substituted imidazoles via MCRs.[Figure not available: see fulltext.].
- Gabla, Jenifer J.,Lathiya, Dharmesh R.,Revawala, Akash A.,Maheria, Kalpana C.
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p. 1863 - 1881
(2019/01/04)
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- In vitro evaluation of arylsubstituted imidazoles derivatives as antiprotozoal agents and docking studies on sterol 14α-demethylase (CYP51) from Trypanosoma cruzi, Leishmania infantum, and Trypanosoma brucei
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There is an urgent need to discover and develop new drugs to combat parasitic diseases as Chagas disease (Trypanosoma cruzi), sleeping sickness (Trypanosoma brucei), and leishmaniasis (Leishmania ssp.). These diseases are considered among the 13 most unattended diseases worldwide according to the WHO. In the present work, the synthesis of 14 arylsubstituted imidazoles and its molecular docking onto sterol 14α-demethylase (CYP51) was executed. In addition, the compounds, antiprotozoal activity against T. brucei, T. cruzi, Trypanosoma brucei rhodesiense, and Leishmania infantum was evaluated. In vitro antiparasitic results of the arylsubstituted imidazoles against T. brucei, T. cruzi, T.b. rhodesiense, and L. infantum indicated that all samples from arylsubstituted imidazole compounds presented interesting antiparasitic activity to various extent. The ligands 5a, 5c, 5e, 5f, 5g, 5i, and 5j exhibited strong activity against T. brucei, T. cruzi, T.b. rhodesiense, and L. infantum with IC50 values ranging from 0.86 to 10.23?μM. Most samples were cytotoxic against MRC-5 cell lines (1.12 50 2, SO3H, and OH groups interacts with the Fe2+ ion of the Heme group.
- Rojas Vargas, Julio Alberto,López, América García,Pérez, Yulier,Cos, Paul,Froeyen, Matheus
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- Co(II) anchored glutaraldehyde crosslinked magnetic chitosan nanoparticles (MCS) for synthesis of 2,4,5-trisubstituted and 1,2,4,5-tetrasubstituted imidazoles
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A simple, highly efficient and green synthesis of 2,4,5-trisubsituted and 1,2,4,5-tetrasubstituted imidazoles was developed using a novel MCS-GT@Co(II) magnetically recoverable and recyclable catalyst under refluxing conditions with ethanol as a solvent. The catalyst was prepared by immobilization of chitosan onto Fe3O4 using glutaraldehyde as crosslinker followed by Co(II) ion immobilization via cobalt acetate. The catalyst was characterized using various techniques. For organic products determination, 1H NMR, 13C NMR and Fourier transform infrared spectroscopies were used. The reaction was also tried with individual components of the catalyst, but the synergistic effect of the components in the prepared catalyst showed the highest yield and shortest reaction time.
- Singh, Harminder,Rajput, Jaspreet Kaur
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- Appel reagent as novel promoter for the synthesis of polysubstituted imidazoles
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We present an efficient method for the synthesis of polysubstituted imidazoles in the presence of Appel reagent (Ph3P/CCl4). Tri-substituted imidazoles is synthesized via condensation of aldehydes, benzil and ammonium acetate, and tetra-substituted imidazole is prepared via condensation of aldehydes, benzil, ammonium acetate and primary amines. These protocols allow the simple preparation of the desired products using readily available reagent instead of complex, expensive and toxic reagents under mild reaction conditions in excellent yields.
- Khoshneviszadeh, Mehdi,Mahdavi, Mohammad
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p. 343 - 352
(2018/05/07)
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- One-pot synthesis of multisubstituted imidazoles catalyzed by Dendrimer-PWAn nanoparticles under solvent-free conditions and ultrasonic irradiation
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An efficient, green and eco-friendly protocol has been developed for the synthesis of 2,4,5-trisubstituted and 1,2,4,5-tetrasubstituted imidazoles via one-pot condensation reaction using Dendrimer-PWAn as catalyst under solvent-free conditions or ultrasonic irradiation in excellent yields. The reactions under conventional heating conditions were compared with the ultrasonic-assisted reactions. The operational simplicity, practicability and applicability of this protocol to various substrates make it an interesting alternative to previous procedures. The present methodology offers several advantages such as excellent yields, short reaction times, a cleaner reaction, and the absence of any tedious work-up or purification. The catalyst is easily separated from the products by filtration and also exhibits remarkable reusable activity. SEM, BET and DLS of the catalyst were also investigated after each reaction cycle.
- Esmaeilpour, Mohsen,Javidi, Jaber,Dehghani, Farzaneh,Zahmatkesh, Saeed
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p. 163 - 185
(2017/01/14)
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- An efficient green protocol for the synthesis of tetra-substituted imidazoles catalyzed by zeolite BEA: Effect of surface acidity and polarity of zeolite
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In the present study, the catalytic activity of various medium (H-ZSM-5) and large pore (H-BEA, H-Y, H-MOR) zeolites were studied as solid acid catalysts. The zeolite H-BEA is found to be an efficient catalyst for the synthesis of 1-benzyl-2,4,5-triphenyl-1H-imidazoles through one-pot, 4-component reaction (4-CR) between benzil, NH4OAc, substituted aromatic aldehydes and benzyl amine. The hydrophobicity, Si/Al ratio and acidic properties of zeolite BEA were well improved by controlled dealumination. The synthesized materials were characterized by various characterization techniques such as XRD, ICP-OES, BET, NH3-TPD, FT-IR, pyridine FT-IR, 27Al and 1H MAS NMR. It has been observed that the dealumination of the parent zeolite H-BEA (12) results in the enhanced strength of Br?nsted acidity up to a certain Si/Al ratio which is attributed to the inductive effect of Lewis acidic EFAl species, leading to the higher activity of the zeolite BEA (15) catalyst towards the synthesis of 1-benzyl-2,4,5-triphenyl-1H-imidazoles under thermal solvent-free conditions with good to excellent yields. Using the present catalytic synthetic protocol, diverse tetra-substituted imidazoles, which are among the significant biologically active scaffolds, were synthesized in high yield within a shorter reaction time. The effect of polarity, surface acidity and extra framework Al species of the catalysts has been well demonstrated by means of pyridine FT-IR, and 27Al and 1H MAS NMR. The solvent-free synthetic protocol makes the process environmentally benign and economically viable.
- Gabla, Jenifer J.,Mistry, Sunil R.,Maheria, Kalpana C.
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p. 5154 - 5167
(2017/11/09)
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- Glutamic acid as an efficient and green catalyst for the one-pot synthesis of 1,2,4,5-tetrasubstituted imidazoles under thermal, solvent-free conditions
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A high-yielding synthesis of 1,2,4,5-tetrasubstituted imidazoles is described, involving the reaction of 1,2-dicarbonyl compounds, aryl aldehydes, amines and ammonium acetate in the presence of a catalytic amount of glutamic acid under thermal, solvent-free conditions. The salient features of this protocol are aerobic conditions, a non-hazardous green catalyst, short reaction times and mild reaction conditions.
- Feizabad, Fahimeh Khazaee,Khandan-Barani, Khatereh,Hassanabadi, Alireza
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p. 673 - 675
(2017/12/26)
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- A new more atom-efficient multi-component approach to tetrasubstituted imidazoles: One-pot condensation of nitriles, amines and benzoin
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A new more atom-efficient multi-component approach for the synthesis of tetrasubstituted imidazoles via the one-pot condensation of nitriles, primary amines and benzoin has been described. Using this method, a wide range of structurally diverse nitriles and primary amines were successfully condensed with benzoin in glycerol in the presence of TFA under microwave irradiation at 120 °C and all the products were obtained in good to excellent yields with higher atom efficiencies in comparison with the commonly used four-component condensation of aldehydes, ammonium acetate, primary amines and benzil.
- Khalafi-Nezhad, Ali,Shekouhy, Mohsen,Sharghi, Hashem,Aboonajmi, Jasem,Zare, Abdolkarim
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p. 67281 - 67289
(2016/07/30)
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- Preparation of 1,2,4,5-tetrasubstituted imidazoles over magnetic core–shell titanium dioxide nanoparticles
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Magnetic core–shell titanium dioxide nanoparticles (Fe3O4@SiO2@TiO2) were applied for the efficient preparation of 1,2,4,5-tetrasubstituted imidazole derivatives by the one-pot multi-component condensation of be
- Khazaei, Ardeshir,Moosavi-Zare, Ahmad Reza,Gholami, Fatemeh,Khakyzadeh, Vahid
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p. 691 - 694
(2016/07/19)
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- Increased SBA-15-SO3H catalytic activity through hydrophilic/hydrophobic fluoroalkyl-chained alcohols (RFOH/SBA-15-Pr-SO3H)
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A superior catalytic activity for the SBA-15-functionalized sulfonic acid containing fluoroalkyl chain alcohols (RFOH/SBA-15-Pr-SO3H adduct) is presented for the synthesis of highly substituted imidazoles. The advantages of this method include low catalyst loading, simple procedure, excellent yields, recyclability of catalyst, and short reaction times.
- Rostamnia, Sadegh,Doustkhah, Esmail
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p. 1345 - 1347
(2015/06/16)
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- One-pot synthesis of multisubstituted imidazoles under solvent-free conditions and microwave irradiation using Fe3O4@SiO2-imid-PMAn magnetic porous nanospheres as a recyclable catalyst
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An efficient, green and ecofriendly procedure has been developed using Fe3O4@SiO2-imid-PMAn as a magnetic catalyst for a rapid and improved synthesis of 2,4,5-trisubstituted and 1,2,4,5-tetrasubstituted imidazoles under solvent-free conditions and microwave irradiation in excellent yields. The reactions under conventional heating conditions were compared with the microwave-assisted reactions. The operational simplicity, practicability and applicability of this protocol to various substrates make it an interesting alternative to previous procedures. The present approach offers several advantages such as short reaction times, high yields, simplicity of operation, easy work-up, a cleaner reaction and ease of recovery and reusability of the catalyst using a magnetic field. Also, the nanocatalyst can be easily recovered by the application of a magnetic field and reused for the next reactions at least 5 times without distinct deterioration in catalytic activity. SEM, BET, DLS and leaching of the catalyst after each reaction cycle were investigated.
- Esmaeilpour, Mohsen,Javidi, Jaber,Zandi, Maryam
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p. 3388 - 3398
(2015/05/20)
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- (Carboxy-3-oxopropylamino)-3-propylsilylcellulose as a novel organocatalyst for the synthesis of substituted imidazoles under solvent-free conditions
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(Carboxy-3-oxopropylamino)-3-propylsilylcellulose (COPAPSC), a novel organocatalyst, has been prepared by a synthesis grafting of -COOH functionalized organosilanes on a cellulose using surface hydroxyl groups as anchor points. The -CO2H group-functionalized cellulose was synthesized via the consecutive surface functionalization with 3-aminopropyltriethoxysilane (3-APTES) followed by the condensation of the surface -NH2 groups with succinic anhydride. COPAPSC is used as a catalyst for the synthesis of tri- and tetra-substituted imidazoles from the reaction of benzil, aromatic aldehydes, ammonium acetate, and amines under solvent-free conditions. The key advantages of this process are high yields, easy work-up, purification of products by non-chromatographic methods and the reusability of the catalyst.
- Salimi, Mehri,Nasseri, Mohammad Ali,Chapesshloo, Tayyebeh Daliran,Zakerinasab, Batol
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p. 33974 - 33980
(2015/04/27)
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- β-Cyclodextrin-propyl sulfonic acid catalysed one-pot synthesis of 1,2,4,5-tetrasubstituted imidazoles as local anesthetic agents
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Some functionalized 1,2,4,5-tetrasubstituted imidazole derivatives were synthesized using a one-pot, four component reaction involving 1,2-diketones, aryl aldehydes, ammonium acetate and substituted aromatic amines. the synthesis has been efficiently carried out in a solvent free medium using β-cyclodextrin-propyl sulfonic acid as a catalyst to afford the target compounds in excellent yields. the local anesthetic effect of these derivatives was assessed in comparison to lidocaine as a standard using a rabbit corneal and mouse tail anesthesia model. the three most potent promising compounds were subjected to a rat sciatic nerve block assay where they showed considerable local anesthetic activity, along with minimal toxicity. among the tested analogues, 4-(1-benzyl-4,5-diphenyl-1h-imidazol-2-yl)-n,n-dimethylaniline (5g) was identified as most potent analogue with minimal toxicity. it was further characterized by a more favourable therapeutic index than the standard.
- Yan, Ran,Ming, Li,Zong-Ze, Zhang
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p. 20286 - 20296
(2015/12/23)
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- Facile preparation of a nanostructured functionalized catalytically active organosalt
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We report a novel nanostructured organosalt, based on sulfonic acid functionalized pyrazinium {[H-pyrazine-SO3H]Cl2} that was synthesized and characterized by several techniques including Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), thermal gravimetric analysis (TGA), differential thermal gravimetric (DTG) analysis, transmission electron microscopy (TEM), mass spectrometry (MS), proton NMR (1H NMR), carbon-13 NMR (13C NMR) and also electron diffraction (ED) patterns. Results proved that the unprecedented sulfonated pyrizinium organosalt is indeed nanostructured and highly crystalline as supported by TEM, ED and XRD studies, having an average nanoparticle size of 50 nm according to TEM micrographs. The novel nano-organocatalyst was proved to be an efficient catalyst in the synthesis of 1,2,4,5-tetrasubstituted imidazoles by a one-pot multi-component condensation of benzil, a broad range of aldehydes, primary amines and ammonium acetate at 90 °C under solvent-free conditions.
- Moosavi-Zare, Ahmad Reza,Zolfigol, Mohammad Ali,Khakyzadeh, Vahid,Boettcher, Christoph,Beyzavi, Mohammad Hassan,Zare, Abdolkarim,Hasaninejad, Alireza,Luque, Rafael
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p. 770 - 777
(2014/01/06)
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- One pot synthesis of 1,2,4,5-tetrasubstituted-imidazoles catalyzed by trityl chloride in neutral media
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Trityl chloride (TrCl or Ph3CCl) efficiently catalyzes the one-pot multi-component condensation of benzil with aldehydes, primary amines and ammonium acetate under neutral and solvent-free conditions to give 1,2,4,5-tetrasubstituted imidazoles in high to excellent yields and in short reaction times. Mechanistically, it is attractive that trityl chloride promotes the reaction by in situ generation of trityl carbocation (Ph3C+).
- Moosavi-Zare, Ahmad Reza,Asgari, Zhila,Zare, Abdolkarim,Zolfigol, Mohammad Ali,Shekouhy, Mohsen
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p. 60636 - 60639
(2015/02/19)
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- One-pot synthesis of polysubstituted imidazoles in a bronsted acidic deep eutectic solvent
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A Bronsted acidic deep eutectic solvent based on choline chloride and p-toluenesulfonic acid was prepared and was found to be effective for the one-pot synthesis of 2,4,5-trisubstituted and 1,2,4,5-tetrasubstituted imidazoles with high yields. In addition, the deep eutectic solvent is non-toxic, cost-effective and recyclable.
- Wang, Liang,Zhong, Xia,Zhou, Min,Zhou, Wei-You,Chen, Qun,He, Ming-Yang
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p. 236 - 238
(2013/07/05)
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- Catalytic procedures for multicomponent synthesis of imidazoles: Selectivity control during the competitive formation of tri- and tetrasubstituted imidazoles
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The catalytic potential of different fluoroboric acid-derived catalyst systems viz. aq HBF4, solid supported HBF4, metal tetrafluoroborates (inorganic salts), solid supported metal tetrafluoroborates, and tetrafluoroborate based ionic liquids (organic salts) were investigated for the three component reaction (3-MCR) of 1,2-diketone, aldehyde, and ammonium salts to form 2,4,5-trisubstituted imidazoles and the four component reaction (4-MCR) involving 1,2-diketone, aldehyde, amine and ammonium acetate to form 1,2,4,5-tetrasubstituted imidazoles. The HBF4-SiO2 was found to be the stand out catalyst for both the 3-MCR and 4-MCR processes. The next most effective catalysts are LiBF4 and Zn(BF4) 2 to form 2,4,5-trisubstituted and 1,2,4,5-tetrasubstituted imidazoles via the 3-MCR and 4-MCR, respectively. This is the first report on the unaddressed issue of competitive formation of 2,4,5-trisubstituted imidazole during the 4-MCR involving 1,2-diketone, aldehyde, amine and ammonium acetate and highlights the influence of the catalyst systems in controlling the selective formation of tetra substituted imidazole. The metal salt of weak protic acids drive selectivity towards tetra substituted imidazole in the order tetrafluoroborates > perchlorates > triflates. The catalytic potency of tetrafluoroborates was in the order Zn(BF4)2 > Co(BF4)2 > AgBF4 ≈ Fe(BF 4)2 > NaBF4 ≈ LiBF4 ≈ Cu(BF4)2. The developed protocols worked well for different diketones, various aryl, heteroaryl, and alkyl aldehydes and in the case of the preparation of 1,2,4,5-tetrasubstituted imidazoles different amines can be used. The effectiveness of different ammonium salts as nitrogen source has been investigated and ammonium acetate is proved to be the best. The HBF4-SiO2 is recyclable for five consecutive uses without significant loss of catalytic activity. The Royal Society of Chemistry 2012.
- Kumar, Dinesh,Kommi, Damodara N.,Bollineni, Narendra,Patel, Alpesh R.,Chakraborti, Asit K.
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experimental part
p. 2038 - 2049
(2012/08/27)
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- Efficient multi-component synthesis of highly substituted imidazoles utilizing P2O5/SiO2 as a reusable catalyst
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Phosphorus pentoxide supported on silica gel (P2O 5/SiO2) has been used as an efficient and reusable catalyst for the one-pot pseudo four-component synthesis of 2,4,5-trisubstituted imidazoles from benzil or benzoin, aldehydes, and ammonium acetate. It was also used for four-component preparation of 1,2,4,5-tetrasubstituted imidazoles from benzil or benzoin, aldehydes, primary amine, and ammonium acetate under thermal solvent-free conditions. The remarkable features of this new procedure are high conversions, cleaner reaction, simple experimental and work-up procedures and also the catalyst can be easily separated from the reaction mixture and reused several times without any loss of its activity.
- Shaterian, Hamid Reza,Ranjbar, Mohammad,Azizi, Kobra
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experimental part
p. 1635 - 1645
(2012/01/06)
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- Synthesis of highly substituted imidazoles using Bronsted acidic ionic liquid, triphenyl(propyl-3-sulphonyl)phosphonium toluenesulfonate, as reusable catalyst
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Bronsted acidic ionic liquid, triphenyl(propyl-3-sulphonyl) phosphonium toluenesulfonate, has been used as an efficient and reusable catalyst for the one-pot synthesis of 2,4,5-trisubstituted and 1,2,4,5-tetrasubstituted imidazoles under solvent-free conditions in excellent yields.
- Shaterian,Ranjbar,Azizi
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experimental part
p. 1120 - 1134
(2012/02/04)
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- An environmental friendly approach for the synthesis of highly substituted imidazoles using Br?nsted acidic ionic liquid, N-methyl-2-pyrrolidonium hydrogen sulfate, as reusable catalyst
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Br?nsted acidic ionic liquid, N-methyl-2-pyrrolidonium hydrogen sulfate, has been used as an efficient and reusable catalyst for the one-pot synthesis of 2,4,5-trisubstituted and 1,2,4,5-tetrasubstituted imidazoles under thermal solvent-free conditions in excellent yields.
- Shaterian, Hamid Reza,Ranjbar, Mohammad
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experimental part
p. 40 - 49
(2012/03/09)
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- One-pot synthesis of 1,2,4,5-tetrasubstituted and 2,4,5-trisubstituted imidazoles by zinc oxide as efficient and reusable catalyst
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ZnO is an efficient, readily available, and reusable catalyst for the one-pot synthesis of 1,2,4,5-tetrasubstituted and 2,4,5-trisubstituted imidazoles. This procedure is very simple and affords excellent yields.
- Bahrami, Kiumars,Khodaei, Mohammad M.,Nejati, Akbar
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experimental part
p. 159 - 162
(2011/10/04)
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- One-pot synthesis of tetrasubstituted imidazoles catalyzed by preyssler-type heteropoly acid
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A simple one-pot four-component synthetic method was reported for the preparation of tetrasubstituted imidazole derivatives from benzil, aromatic aldehydes, primary amines and ammonium acetate in the presence of Preyssler-type heteropoly acid catalyst. This method was proved to be ecobenign, easy work-up, convenient, relatively short reaction times and the products were isolated with high yields.
- Javid, Ali,Heravi, Majid M.,Bamoharram,Nikpour, Mohsen
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experimental part
p. 547 - 552
(2012/02/16)
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- Carbon-based solid acid as an efficient and reusable catalyst for one-pot synthesis of tetrasubstituted imidazoles under solvent-free conditions
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Carbon-based solid acid catalyst was found to be highly efficient, eco-friendly and recyclable heterogeneous catalyst for the multicomponent reaction of benzil, aromatic aldehyde, primary amine and ammonium acetate, giving rise to 1,2,4,5-tetrasubstituted imidazoles in good to excellent yields. The present methodology offers several advantages, such as high yields, short reaction time, mild reaction condition and a recyclable catalyst with a very easy work up. Carbon-based solid acid catalyst was found to be highly efficient, eco-friendly and recyclable heterogeneous catalyst for the multicomponent reaction of benzil, aromatic aldehyde, primary amine and ammonium acetate for the synthesis of 1,2,4,5- tetrasubstituted imidazoles in good to excellent yields. The present methodology offers several advantages, such as high yields, short reaction time, mild reaction condition and a recyclable catalyst with a very easy work up. Copyright
- Tavakoli-Hoseini, Niloofar,Davoodnia, Abolghasem
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experimental part
p. 203 - 206
(2012/03/26)
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- Catalyst-free one-pot four component synthesis of polysubstituted imidazoles in neutral ionic liquid 1-butyl-3-methylimidazolium bromide
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A catalyst-free one-pot four component methodology for the synthesis of 1,2,4,5-substituted imidazoles under conventional heating and microwave irradiation using 1-butyl-3-methylimidazolium bromide, [Bmim]Br, as a neutral reaction media is described. A broad range of structurally diverse aldehydes (aromatic aldehydes bearing electron withdrawing and/or electron releasing groups as well as heteroaromatic aldehydes) and primary amines (aromatic and aliphatic) were applied successfully, and corresponding products were obtained in good to excellent yields without any byproduct.
- Hasaninejad, Alireza,Zare, Abdolkarim,Shekouhy, Mohsen,Ameri Rad, Javad
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experimental part
p. 844 - 849
(2011/01/13)
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- Green, one-pot, solvent-free synthesis of 1,2,4,5-tetrasubstituted imidazoles using a bronsted acidic ionic liquid as novel and reusable catalyst
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3-Methyl-1-(4-sulfonic acid)butylimidazolium hydrogen sulfate [(CH 2)4SO3HMIM][HSO4], a Brnsted acidic ionic liquid, has been used as an efficient, green, and reusable catalyst for the synthesis of 1,2,4,5-tetrasubstituted imidazoles using benzil, an aromatic aldehyde, and a primary amine in the presence of ammonium acetate under solvent-free conditions. The catalyst could be recycled and reused several times without noticeably decreasing the catalytic activity. Taylor & Francis Group, LLC.
- Davoodnia, Abolghasem,Heravi, Majid M.,Safavi-Rad, Zahra,Tavakoli-Hoseini, Niloofar
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experimental part
p. 2588 - 2597
(2010/10/03)
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- BF3·SiO2: an efficient reagent system for the one-pot synthesis of 1,2,4,5-tetrasubstituted imidazoles
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Silica-supported boron trifluoride (BF3·SiO2) is an efficient, readily available and reusable catalyst for the synthesis of 1,2,4,5-tetrasubstituted imidazoles using benzil, an aromatic aldehyde and an amine in the presence of ammonium acetate. This one-pot procedure is very simple, affording good to excellent yields.
- Sadeghi, Bahareh,Mirjalili, Bi Bi Fatemeh,Hashemi, Mohammad M.
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p. 2575 - 2577
(2008/09/21)
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- One-pot synthesis of tetra-substituted imidazoles on silica gel under microwave irradiation
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A new procedure for synthesis of tetra-substituted imidazoles was developed. A series of imidazole derivatives including six new compounds were synthesized by this procedure via condensation of benzoin, aromatic aldehyde, amine and ammonium acetate in the presence of silica gel under solvent-free microwave irradiation.
- Xu, Yu,Liu, Yan-Zhi,Rui, Lei,Liu, Lei,Guo, Qing-Xiang
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- Synthesis and analgesic activity of some 1-benzyl-2-substituted-4,5-diphenyl-1H-imidazole derivatives
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In this study, derivatives of 1-benzyl-2-substituted-4,5-diphenyl-1H-imidazole were synthesized and their analgesic activity assayed in two tests. 1,2,4,5-Tetrasubstituted imidazole compounds were obtained by the treatment of purified imidazole compounds with benzyl chloride in the presence of sodium hydride. The structure elucidation of the compounds was performed by IR, 1H-NMR and mass spectroscopic data and elemental analysis results. Generally the prepared compound exhibited only moderate analgesic activity in mice at the dose of 100 mg/kg i.p.; however, a few of them exhibited good activity, almost equivalent to that of morphine at 1 mg/kg i.p. was observed. At the above dosage, no toxicity was observed for all compounds. Copyright
- Ucucu, Uemit,Karaburun, Nalan Guendogdu,Isikdag, Ilhan
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p. 285 - 290
(2007/10/03)
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