- Experimental and computational study of metal-free Br?nsted acidic ionic liquid catalyzed benzylic C(sp3)–H bond activation and C–N, C–C cross couplings
-
Metal and solvent free synthesis of tetrasubstituted imidazoles and tetrasubstituted pyrazines from 1,2-diketones and aliphatic amines is studied experimentally and computationally. Various ionic liquids (ILs) are taken as a catalyst in 10 mol% for the re
- Valiyev, Isa,Abdullayev, Yusif,Yagubova, Sevinj,Baybekov, Shamkhal,Salmanov, Cavanshir,Autschbach, Jochen
-
-
Read Online
- A solvent-free synthesis of 1,2,4,5-tetrasubstituted imidazoles using molecular iodine as catalyst
-
An efficient method for the synthesis of 1,2,4,5-tetrasubstituted imidazoles by three-component condensation of benzil, benzonitrile derivatives and primary amines under solvent-free conditions using molecular iodine as catalyst is described with high product yields. The significant features of the iodine-catalysed condensation are operational simplicity, inexpensive reagents, high yield of products and use of non-toxic reagents.
- Ren, Yi-Ming,Cai, Chun
-
-
Read Online
- One-pot synthesis of tetra-substituted imidazoles on silica gel under microwave irradiation
-
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
-
-
Read Online
- Carbon-based solid acid as an efficient and reusable catalyst for one-pot synthesis of tetrasubstituted imidazoles under solvent-free conditions
-
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
-
-
Read Online
- A novel one-pot synthesis of tetrasubstituted imidazoles under solvent-free conditions and microwave irradiation
-
The one-pot, three-component condensation of benzil, benzonitrile derivatives and primary amines on the surface of silica gel under solvent-free conditions and microwave irradiation provided tetrasubstituted imidazoles in high yields.
- Balalaie, Saeed,Hashemi, Mohammed M.,Akhbari, Maryam
-
-
Read Online
- Increased SBA-15-SO3H catalytic activity through hydrophilic/hydrophobic fluoroalkyl-chained alcohols (RFOH/SBA-15-Pr-SO3H)
-
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
-
-
Read Online
- One-pot synthesis of polysubstituted imidazoles in a bronsted acidic deep eutectic solvent
-
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
-
-
Read Online
- Silica coated magnetic NiFe2O4 nanoparticle supported phosphomolybdic acid; Synthesis, preparation and its application as a heterogeneous and recyclable catalyst for the one-pot synthesis of tri- and tetra-substituted imidazoles under solvent free conditions
-
In this research, a magnetically-recoverable catalyst (NiFe2O4@SiO2-H3PMo12O40) was prepared by supporting phosphomolybdic acid (H3PMo12O40) onto silica-coated NiFe2O4 nanoparticles. The prepared sample was characterized by FT-IR, TEM, SEM and VSM techniques and then the catalytic activity of this catalyst was investigated in the synthesis of tri- and tetra-substituted imidazole derivatives. More importantly, the catalyst was easily isolated from the reaction mixture by a magnetic bar and reused at least ten times without significant degradation in its activity.
- Maleki, Behrooz,Eshghi, Hossein,Khojastehnezhad, Amir,Tayebee, Reza,Ashrafi, Samaneh Sedigh,Kahoo, Golnoosh Esmailian,Moeinpour, Farid
-
-
Read Online
- Amberlyst A-15: Reusable catalyst for the synthesis of 2,4,5-trisubstituted and 1,2,4,5-Tetrasubstituted-1H-Imidazoles under MW irradiation
-
One-pot multi-component condensation of benzyl, aldehydes, ammonium acetate and primary amines were used for synthesis of 2,4,5-trisubstituted and 1,2,4,5-tetrasubstituted-1H-imidazole derivatives underMWradiation using amberlyst A-15 as a catalysts. This catalyst has several advantages (simple work-up, low cost and reusability) . Indian Academy of Sciences.
- Pandit, Shivaji S.,Bhalerao, Swapnil K.,Aher, Uddhav S.,Adhav, Gorakshanath L.,Pandit, Vikram U.
-
-
Read Online
- BF3·SiO2: an efficient reagent system for the one-pot synthesis of 1,2,4,5-tetrasubstituted imidazoles
-
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.
-
-
Read Online
- SbCl5.SiO2: An efficient alternative for one-pot synthesis of 1,2,4,5-tetrasubstituted imidazoles in solvent or under solvent-free condition
-
In a one-pot four-component reaction, an aldehyde, an amine, benzil and ammonium acetate were condensed for the synthesis of 1,2,4,5-tetrasubstituted imidazoles in the presence of silica supported antimony pentachloride (SbCl 5.SiO2) in improved yields. The catalyst is recoverable by simple filtration and can be used in the subsequent reactions.
- Sadeghi,Mirjalili,Bidaki,Ghasemkhani
-
-
Read Online
- Elemental Sulfur-Promoted Aerobic Cyclization of Ketones and Aliphatic Amines for Synthesis of Tetrasubstituted Imidazoles
-
Elemental sulfur-promoted cyclization for the one-pot synthesis of tetra-substituted imidazoles from benzylamines and ketones is described. Elemental sulfur combined with molecular oxygen as the benign co-oxidant was found to be the key for the high efficiency of this transformation under metal-free conditions. A range of tetrasubstituted imidazoles were synthesized from simple ketones and amines with good functional group tolerance. (Figure presented.).
- Chen, Xiangui,Wang, Zhen,Huang, Huawen,Deng, Guo-Jun
-
-
Read Online
- Green, one-pot, solvent-free synthesis of 1,2,4,5-tetrasubstituted imidazoles using a bronsted acidic ionic liquid as novel and reusable catalyst
-
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
-
-
Read Online
- Efficient room-temperature synthesis of tri- and tetrasubstituted imidazoles catalyzed by ZrCl4
-
A general protocol has been developed for the rapid synthesis of 2,4,5-trisubstituted and 1,2,4,5-tetrasubstituted imidazoles in high yields using ZrCl4 as an efficient catalyst at room temperature. A variety of aromatic, aliphatic, and terpenoidal aldehydes underwent condensation with NH4OAc/amines to give the imidazoles. Similarly, the imidazole glycoconjugates are prepared in good yields from the corresponding glycosyl aldehydes. Copyright Taylor & Francis Group, LLC.
- Sharma,Jyothi,Lakshmi, P. Sree
-
-
Read Online
- 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
-
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
-
-
Read Online
- 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
-
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
-
-
Read Online
- Fe3O4@THAM-Pd as a highly efficient magnetically recoverable nanocatalyst for facile one-pot assembly of substituted imidazoles under solvent-free conditions
-
The current work has been explored an expeditious tactic toward one-pot multicomponent synthesis of 1,2,4,5-tetrasubstituted and 2,4,5-trisubstituted imidazoles using Fe3O4@THAM-Pd MNPs as an effective catalyst. With readily accessible benzil, ammonium acetate, anilines, and aromatic aldehydes as the simple starting materials, the condensation is run under solvent-free conditions to afford the target products in high yields. The other salient features of the present catalytic system are a simple work-up process, shorter reaction times, ease of preparation and handling of the catalyst, and cleaner reaction profiles. In addition, the sustainability of the methodology was checked by the investigation of the stability and reusability of the catalyst using an external magnet. The results showed that Fe3O4 @THAM-Pd MNPs can be reused for successive five runs without an appreciable decline in catalytic efficiency.
- Sanchooli Tazeh, Kazem,Heydari, Reza,Fatahpour, Maryam
-
-
Read Online
- Four-component, one-pot synthesis of tetra-substituted imidazoles using a catalytic amount of MCM-41 or p-TsOH
-
An improved and rapid one-pot synthesis of tetrasubstituted imidazoles by condensing benzil, ammonium acetate, amines, and aromatic aldehydes and using a catalytic amount of silica structure MCM-41 or p-toluenesulfonic acid (p-TsOH) as efficient, green, reusable catalysts in excellent yields is reported.
- Shoar, Rahim Hekmat,Rahimzadeh, Golnaz,Derikvand, Fatemeh,Farzaneh, Maryam
-
-
Read Online
- Propyl–SO3H functionalized SBA-15: Microwave-mediated green synthesis of biologically active multi-substituted imidazole scaffolds
-
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.
-
-
Read Online
- Cu(II) immobilized on guanidinated epibromohydrin-functionalized γ-Fe2O3@TiO2 (γ-Fe2O3@TiO2-EG-Cu(II)): A highly efficient magnetically separable heterogeneous nanocatalyst for one-pot synthesis of highly substituted imidazoles
-
A simple, efficient and eco-friendly procedure has been developed using Cu(II) immobilized on guanidinated epibromohydrin-functionalized γ-Fe2O3@TiO2 (γ-Fe2O3@TiO2-EG-Cu(II)) for the synthesis of 2,4,5-trisubstituted and 1,2,4,5-tetrasubstituted imidazoles, via the condensation reactions of various aldehydes with benzil and ammonium acetate or ammonium acetate and amines, under solvent-free conditions. High-resolution transmission electron microscopy analysis of this catalyst clearly affirmed the formation of a γ-Fe2O3 core and a TiO2 shell, with mean sizes of about 10–20 and 5–10?nm, respectively. These data were in very good agreement with X-ray crystallographic measurements (13 and 7?nm). Moreover, magnetization measurements revealed that both γ-Fe2O3@TiO2 and γ-Fe2O3@TiO2-EG-Cu(II) had superparamagnetic behaviour with saturation magnetization of 23.79 and 22.12?emu g?1, respectively. γ-Fe2O3@TiO2-EG-Cu(II) was found to be a green and highly efficient nanocatalyst, which could be easily handled, recovered and reused several times without significant loss of its activity. The scope of the presented methodology is quite broad; a variety of aldehydes as well as amines have been shown to be viable substrates. A mechanism for the cyclocondensation reaction has also been proposed.
- Nejatianfar, Mahdi,Akhlaghinia, Batool,Jahanshahi, Roya
-
-
Read Online
- Appel reagent as novel promoter for the synthesis of polysubstituted imidazoles
-
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
-
-
Read Online
- Catalytic activity of Mg-Al hydrotalcites and derived mixed oxides for imination reactionsviaan oxidative-dehydrogenation mechanism
-
The catalytic activities of Mg-Al hydrotalcites and derived Mg-Al mixed oxides were studied for the imination of benzylic substrates (benzyl amine and benzyl alcohol), with aniline as a model reaction, to establish a green and cost-effective catalytic (precious metal free) process for imination and tandem reactions utilizing alcohols as reagents. The Mg-Al mixed oxide (Mg/Al ratio = 3.0) was found to be an efficient catalyst for imination reactions to synthesize cross-imines with high selectivity as well as for tandem reactions of alcohols. Basic sites of catalysts adsorb benzylic substrates through the hydrogen of their functional groups (-NH2/-OH) and activate (weaken) benzylic C-H bonds for hydride elimination. Thus, basic sites catalyze the reaction by activating benzylic substrates for oxidative-dehydrogenation (i.e., deprotonation followed by hydride elimination with the help of oxygen) to produce reactive imine/carbonyl intermediates, which undergo subsequent nucleophilic reactions with amine.
- Vala, Naresh,Joshi, Pradyuman A.,Mishra, Manish
-
supporting information
p. 8859 - 8868
(2020/06/08)
-
- An electrochemical oxidative multicomponent cascade annulation of ketones and amines used to produce imidazoles
-
An electrochemical dehydrogenative [2 + 2 + 1] annulation used for the synthesis of imidazoles has been developed under undivided electrolytic conditions. In an undivided cell, aryl ketones and amines can smoothly participate in this transformation to furnish a variety of substituted imidazoles. The reaction avoids the use of both transition-metal catalysts and peroxide reagents, which makes it more sustainable and renewable.
- Zeng, Liang,Li, Jing,Gao, Jun,Huang, Xunhai,Wang, Wei,Zheng, Xiaohui,Gu, Lijun,Li, Ganpeng,Zhang, Shengyong,He, Yonghui
-
supporting information
p. 3416 - 3420
(2020/06/25)
-
- One-Pot Synthesis of Polysubstituted Imidazoles Based on Pd(OAc) 2 /Ce(SO 4) 2 /Bi(NO 3) 3 Trimetallic Cascade of Decarboxylation/Wacker-Type Oxidation/Debus-Radziszewski Reaction
-
A novel and highly efficient one-pot synthesis of polysubstituted imidazoles from α-hydroxyphenylacetic acids, diphenylacetylene, and amines has been achieved by Pd(OAc) 2 /Ce(SO 4) 2 /Bi(NO 3) 3 trimetallic catalytic system. A series of control experiments showed that this overall reaction occurs through a one-pot cascade process combining the steps of decarboxylation of α-hydroxyphenylacetic acids, Wacker-type oxidation of diphenylacetylene, and Debus-Radziszewski annulation of aryl aldehydes and benzil generated in situ, as well as amines. This reaction represents a novel multicomponent reaction using α-hydroxyphenylacetic acids and diphenylacetylene as sources of aryl aldehydes and a β-diketone. This process exhibits a broad substrate scope and a good functional group tolerance to assemble the corresponding polysubstituted imidazoles in excellent yields (72-88percent) under mild conditions.
- Li, Peilang,Li, Yiqun,Sun, Wei,Zhang, Mingjuan
-
supporting information
p. 3221 - 3230
(2019/08/28)
-
- Co(II) anchored glutaraldehyde crosslinked magnetic chitosan nanoparticles (MCS) for synthesis of 2,4,5-trisubstituted and 1,2,4,5-tetrasubstituted imidazoles
-
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
-
-
- An eco-compatible pathway to the synthesis of mono and bis-multisubstituted imidazoles over novel reusable ionic liquids: An efficient and green sonochemical process
-
Novel and environmentally benign ionic liquids (ILs) comprised of DABCO were successfully synthesized. These ILs were used as robust catalysts for the sonochemical one pot multi-component synthetic route for the functionalized annulated imidazoles in water with excellent yields. The present protocol scored well in terms of yield economy as compared with the conventional procedures. The merits of the current green method include simplicity, applicability, broad functional groups tolerance, clean reaction profiles, and no tedious work-up and they give high-to-quantitative yields. From the environmental viewpoint, these eco-friendly green catalysts can be effortlessly retrieved and reused at least seven successive times without substantial loss in catalytic activity.
- Ahmed Arafa, Wael Abdelgayed
-
p. 16392 - 16399
(2018/05/22)
-
- Alkali stability excellent imidazole and imidazolium cation
-
and membranes and devices comprising the polymers. Also provided are methods of making the inventive compounds and polymers.
- -
-
Paragraph 0241-0242; 0264-0266
(2018/04/13)
-
- Photocatalytic coupling of amines to imidazoles using a Mo-ZnIn2S4 catalyst
-
Substituted imidazoles are traditionally synthesized by co-condensation of multiple feedstocks. Herein, we report a new route for the synthesis of substituted imidazoles via photocyclization of readily available amines at room temperature. The reaction is achieved by the visible-light-induced C-C/C-N bond coupling and subsequent dehydrogenation reaction over Mo-ZnIn2S4 as a heterogeneous photocatalyst. A wide range of amines were converted into the corresponding tri- and tetra-substituted imidazoles with up to 96% total yields. The simplicity, high efficiency and mild condition merits of this new reaction will enable it to be useful in synthetic transformations.
- Wang, Min,Li, Lihua,Lu, Jianmin,Luo, Nengchao,Zhang, Xiaochen,Wang, Feng
-
p. 5172 - 5177
(2017/11/09)
-
- An efficient green protocol for the synthesis of tetra-substituted imidazoles catalyzed by zeolite BEA: Effect of surface acidity and polarity of zeolite
-
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.
-
p. 5154 - 5167
(2017/11/09)
-
- One-pot synthesis of multisubstituted imidazoles catalyzed by Dendrimer-PWAn nanoparticles under solvent-free conditions and ultrasonic irradiation
-
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
-
p. 163 - 185
(2017/01/14)
-
- 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
-
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
-
p. 673 - 675
(2017/12/26)
-
- A new more atom-efficient multi-component approach to tetrasubstituted imidazoles: One-pot condensation of nitriles, amines and benzoin
-
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
-
p. 67281 - 67289
(2016/07/30)
-
- Tri(1-butyl-3-methylimidazolium) gadolinium hexachloride, ([bmim]3[GdCl6]), a magnetic ionic liquid as a green salt and reusable catalyst for the synthesis of tetrasubstituted imidazoles
-
The magnetic ionic liquid, tri(1-butyl-3-methylimidazolium) gadolinium hexachloride, ([bmim]3[GdCl6]), has been used as an efficient green catalyst for the one-pot synthesis of 1,2,4,5-tetrasubstituted imidazoles via the condensation of benzil, an aromatic aldehyde, aniline, and ammonium acetate. Good to excellent yield, mild reaction conditions, as well as ease of operation and work-up are some advantages of the protocol.
- Akbari, Ali
-
supporting information
p. 431 - 434
(2016/01/12)
-
- Intermolecular versus Intramolecular Palladium-Catalyzed Direct Arylations between 1-(2-Bromobenzyl)imidazoles and Aryl Bromides
-
Herein, we report on the sequential palladium-catalyzed intermolecular followed by intramolecular direct arylations of 1-(2-bromobenzyl)imidazoles. We found that, in the presence of 1 mol% palladium acetate and potassium acetate as base, the intermolecular reaction between 1-(2-bromobenzyl)imidazole derivatives and electron-deficient aryl bromides proceeded faster than the intramolecular reaction, allowing us to prepare medium-size polycyclic imidazoles after a second Pd-catalyzed intramolecular arylation. These iterative direct arylations allowed the synthesis of fused nitrogen-containing heterocycles with a 5- or 7-membered-ring in only two steps. Some reactions have also been performed as a one-pot procedure using 2 mol% of palladium acetate in the presence of a larger amount of base (3 equiv.).
- Xu, Xiaowen,Zhao, Liqin,Li, Yiqun,Soulé, Jean-Fran?ois,Doucet, Henri
-
p. 2869 - 2882
(2015/09/28)
-
- Silver-mediated Cα(sp3)-H functionalization of primary amines: An oxidative C-N coupling strategy for the synthesis of two different types of 1,2,4,5-tetrasubstituted imidazoles
-
A new silver(I)-mediated Cα(sp3)-H bond functionalization of primary amines and subsequent oxidative C-N cross-coupling reaction has been demonstrated. This protocol provides a simple, highly efficient, and straightforward approach to form significantly diverse 1,2,4,5-tetrasubstituted imidazoles. In this course of the reaction, a stoichiometric amount of Ag2CO3 was employed. Upon completion of reaction, the silver species was successfully recycled and reused without any loss of activity. Good to excellent yields of the products were readily achieved by using this selective oxidative C-N coupling, which was promoted by a crucial silver(I) salt.
- Sarkar, Rajib,Mukhopadhyay, Chhanda
-
p. 1246 - 1256
(2015/03/04)
-
- Synthesis of Polysubstituted Imidazoles and Pyridines via Samarium(III) Triflate-Catalyzed [2+2+1] and [4+2] Annulations of Unactivated Aromatic Alkenes with Azides
-
Samarium(III) triflate-catalyzed [2+2+1] and [4+2] annulations have been identified for the preparation of fully substituted imidazoles and 2,3,5-trisubstituted pyridines from the readily available unactivated aromatic alkenes and azidomethyl aromatics. T
- Wang, Yingchun,Li, Jiuling,He, Yan,Xie, Yuyang,Wang, Hengshan,Pan, Yingming
-
p. 3229 - 3241
(2015/11/03)
-
- 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
-
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
-
p. 3388 - 3398
(2015/05/20)
-
- γ-Alumina nanoparticle catalyzed efficient synthesis of highly substituted imidazoles
-
γ-Alumina nano particle catalyzed multi component reaction of benzil, arylaldehyde and aryl amines afforded the highly substituted 1,2,4,5-tetraaryl imidazoles with good to excellent yield in less reaction time under the sonication as well as the conventional methods. Convenient operational simplicity, mild conditions and the reusability of catalyst were the other advantages of this developed protocol.
- Reddy, Bandapalli Palakshi,Vijayakumar, Vijayaparthasarathi,Arasu, Mariadhas Valan,Al-Dhabi, Naif Abdullah
-
p. 19221 - 19235
(2015/11/27)
-
- Imidazolium Cations with Exceptional Alkaline Stability: A Systematic Study of Structure-Stability Relationships
-
Highly base-stable cationic moieties are a critical component of anion exchange membranes (AEMs) in alkaline fuel cells (AFCs); however, the commonly employed organic cations have limited alkaline stability. To address this problem, we synthesized and characterized the stability of a series of imidazolium cations in 1, 2, or 5 M KOH/CD3OH at 80 °C, systematically evaluating the impact of substitution on chemical stability. The substituent identity at each position of the imidazolium ring has a dramatic effect on the overall cation stability. We report imidazolium cations that have the highest alkaline stabilities reported to date, >99% cation remaining after 30 days in 5 M KOH/CD3OH at 80 °C.
- Hugar, Kristina M.,Kostalik, Henry A.,Coates, Geoffrey W.
-
supporting information
p. 8730 - 8737
(2015/07/27)
-
- Synthesis of tetra-substituted imidazoles and 2-imidazolines by Ni(0)-catalyzed dehydrogenation of benzylic-type imines
-
Ni(0)-catalyzed dehydrogenation of benzylic-type imines was performed to yield asymmetrical tetra-substituted imidazoles and 2-imidazolines. This was achieved with a single operational step while maintaining good selectivity and atom economy. The catalytic system shows low to moderate tolerance for fluoro-, trifluoromethyl-, methyl-, and methoxy-substituted benzylic-type imines. In addition, the substitution pattern at the N-heterocyclic products was easily controlled by the appropriate selection of R-groups in the starting organic substrates. Based on experimental observations, we propose a reaction mechanism in which benzylic C(sp3)-H bond activation and insertion steps play pivotal roles in this nickel-catalyzed organic transformation. This journal is
- Tlahuext-Aca, Adrian,Hernndez-Fajardo, Oscar,Arvalo, Alma,Garca, Juventino J.
-
p. 15997 - 16005
(2015/02/02)
-
- Ni(ii)-salt catalyzed activation of primary amine-sp3C α-H and cyclization with 1,2-diketone to tetrasubstituted imidazoles
-
NiCl2·6H2O and Ni(OAc)2· 4H2O were found as efficient catalysts for C-H activation of benzyl and aliphatic amines for an unprecedented multi C-N bond forming cyclization with 1,2-diketones under refluxing toluene to furnish highly substituted and polycyclic imidazoles.
- Samanta, Srikanta,Roy, Dipanwita,Khamarui, Saikat,Maiti, Dilip K.
-
supporting information
p. 2477 - 2480
(2014/03/21)
-
- New conditions for the effective synthesis of tri and tetrasubstituted imidazoles catalysed by recyclable indium (III) triflate and magnesium sulfate heptahydrate
-
A one-pot three or four component reaction of wide range of aromatic aldehydes, benzil, aliphatic and aromatic primary amines and ammonium acetate is reported for the synthesis of tri/tetra-substituted imidazoles under solvent-free conditions. Indium (III) trifluoromethanesulfonate and magnesium sulfate heptahydrate as two highly efficient and recyclable catalysts perform a key factor to synthesis of imidazole derivatives with high yields.
- Karami, Bahador,Ferdosian, Roghayeh,Eskandari, Khalil
-
-
- Facile preparation of a nanostructured functionalized catalytically active organosalt
-
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
-
p. 770 - 777
(2014/01/06)
-
- One-pot synthesis of 1,2,4,5-tetrasubstituted imidazoles in ionic liquid
-
The four-component condensation of benzil, aromatic aldehyde, primary amine, and ammonium acetate catalyzed by TFA in ionic liquid [Bpy]BF4 at 80C provided 1,2,4,5-tetrasubstituted imidazoles in moderate to high yields.
- Wan, Yu,Liu, Gui-Xiang,Zhao, Ling-Ling,Wang, Hai-Ying,Huang, Shu-Ying,Chen, Liang-Feng,Wu, Hui
-
p. 713 - 718
(2014/06/10)
-
- One pot synthesis of 1,2,4,5-tetrasubstituted-imidazoles catalyzed by trityl chloride in neutral media
-
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
-
p. 60636 - 60639
(2015/02/19)
-
- Selective sequential cross-coupling reactions on imidazole towards neurodazine and analogues
-
Polysubstituted imidazoles represent a common structural motif in bioactive molecules. A modular and flexible strategy towards 2,4,5-triarylated imidazoles is reported applying a Suzuki-Miyaura cross-coupling protocol. Employing 1-protected 2,4,5-tribromoimidazole as starting material, both stepwise and one-pot protocols towards the title compounds are disclosed. The utility of the approach was demonstrated by synthesizing neurodazine, a biologically active molecule affecting neuronal cell differentiation.
- Recnik, Lisa-Maria,Abd El Hameid, Mohammed,Haider, Maximilian,Schnuerch, Michael,Mihovilovic, Marko D.
-
p. 1387 - 1405
(2013/07/05)
-
- Practical synthesis of polysubstituted imidazoles via iodine- Catalyzed aerobic oxidative cyclization of aryl ketones and benzylamines
-
A practical synthetic method for polysubstituted imidazoles via iodine-catalyzed aerobic oxidative cyclization of aryl ketones and benzylamines has been developed. It was found to tolerate a broad range of substrates to prepare polysubstituted imidazole derivatives in a one-pot manner, and thus importantly allowed product diversity for imidazole chemistry. Additionally, the resultant 1,2,4-trisubstituted imidazoles could be conveniently transformed to functionalized 1,2,4,5-tetrasubstituted imidazoles via electrophilic substitution or direct C-H functionalization, or 2,4-diaryl-1H-imidazoles by debenzylation reaction, which further indicates potential applications of this method in synthetic and pharmaceutical chemistry. Copyright
- Huang, Huawen,Ji, Xiaochen,Wu, Wanqing,Jiang, Huanfeng
-
p. 170 - 180
(2013/03/13)
-
- Tungstate sulfuric acid (TSA): A green and highly efficient catalyst for novel and known polysubstituted imidazoles synthesis
-
Tungstate sulfuric acid (TSA) was composed of anhydrous sodium tungstate and chlorosulfonic acid with a new modified and efficient method. Catalyst was characterized by powdered X-ray diffraction (XRD), X-ray fluorescence (XRF), FT-IR spectroscopy and titration with NaOH (0.1 N). In the present study, highly efficient role of TSA as a catalyst in polysubstituted imidazoles synthesis as pharmaceuticaly important molecules via condensation between a wide range of aryl aldehydes, primary amines, benzil, and ammonium acetate in solventless conditions is reported. Therefore, new application of this catalyst to synthesize some novel imidazoles is introduced.
- Karami, Bahador,Eskandari, Khalil,Azizi, Mahboobeh
-
p. 722 - 732
(2014/03/21)
-
- Nano Fe3O4: A novel and magnetically recyclable catalyst for the synthesis of 1,2,4,5-tetrasubstituted imidazoles in solvent-free conditions
-
A convenient and efficient one-pot four-component synthesis of 1,2,4,5-tetrasubstituted imidazoles using nano Fe3O4 as magnetically recyclable catalyst is reported. The results show that the methodology has several advantages such as low loading of catalyst, excellent yield, short reaction time, operational simplicity and solvent-free conditions.
- Montazeri, Naser,Pourshamsian, Khalil,Rezaei, Hamideh,Fouladi, Mahdi,Rahbar, Sasan
-
p. 3463 - 3466
(2013/04/24)
-
- Lewis acid catalyst free synthesis of substituted imidazoles in 2,2,2-trifluoroethanol
-
A simple, inexpensive, environmentally friendly, and efficient route for the synthesis of highly substituted imidazoles by the condensation of 1,2-dicarbonyl compounds, aldehydes, and ammonium acetate using 2,2,2-trifluoroethanol as a solvent is described. The solvent can be readily separated from reaction products and recovered in excellent purity for direct reuse.
- Khaksar, Samad,Alipour, Mandana
-
p. 395 - 398
(2013/05/21)
-
- Catalytic procedures for multicomponent synthesis of imidazoles: Selectivity control during the competitive formation of tri- and tetrasubstituted imidazoles
-
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.
-
scheme or table
p. 2038 - 2049
(2012/08/27)
-
- An effective and new method for the synthesis of polysubstituted imidazoles by the use of CrCl3.6H2O as a green and reusable catalyst: Synthasis of some novel imidazole derivatives
-
New, efficient and environmentally adapted synthesis of polysubstituted imidazoles in one-pot is found. The multicomponent reaction of various aldehydes, benzil, aliphatic and aromatic primary amines and ammonium acetate under solvent-free condition is explained. The highly efficient role of CrCl3.6H2O as catalyst in this synthesis was shown. By this advantage, several polysubstituted imidazoles as pharmaceutical important molecules can be prepared in high yield and high purity. This method is a very easy and a rapid reaction for the synthesis of imidazole derivatives. The crude products recrystallized to afford the crystalline pure products. Furthermore, catalyst exhibited remarkable reusable activity.
- Karami, Bahador,Eskandari, Khalil,Farahi, Mahnaz,Barmas, Akram
-
experimental part
p. 473 - 479
(2012/07/14)
-
- Facile and rapid synthesis of some novel polysubstituted imidazoles by employing magnetic Fe3O4 nanoparticles as a high efficient catalyst
-
Multicomponent, one-pot, highly efficient, and environmentally adapted synthesis of some novel polysubstituted imidazoles by the use of various aldehydes, benzil, aliphatic, and aromatic primary amines and ammonium acetate in the presence of Fe3O4 nanoparticles as catalyst under solvent-free condition is explained. A highly efficient role of Fe3O4 nanoparticles as catalyst in this synthesis was shown. By this advantage, several polysubstituted imidazoles as pharmaceutical important molecules can be prepared in high yield and high purity. This method is very easy and rapid for the synthesis of imidazole derivatives. All products were deduced from their IR and NMR spectroscopic data. The Fe3O4 nanoparticles were characterized by powdered X-ray diffraction (XRD), transmission electron microscopy (TEM), and FT-IR spectroscopy. TUeBITAK.
- Karami, Bahador,Eskandari, Khalil,Ghasemi, Abdolmohammad
-
experimental part
p. 601 - 613
(2012/08/27)
-
- Facile and rapid synthesis of polysubstituted imidazoles by employing Y(NO3)3×6H2O as catalyst
-
An efficient and environmentally adapted synthesis of polysubstituted imidazoles in one-pot and multicomponent reaction of various aldehydes, benzil, aliphatic and aromatic primary amines and ammonium acetate under solvent-free condition is reported. Highly efficient role of Y(NO3) 3×6H2O as catalyst in this synthesis was shown. By this advantage, several polysubstituted imidazoles as pharmaceutical important molecules can be prepared in high yield and high purity. This method is very easy and rapid for the synthesis of imidazole derivatives. All products were deduced from their IR and NMR spectroscopic and elemental analysis data. The catalyst exhibited remarkable reusable activity.
- Karami, Bahador,Dehghani, Fatemeh Mohammadpour,Eskandari, Khalil
-
p. 147 - 153,7
(2020/09/09)
-
- Sulfonated carbon/silica composite functionalized Lewis acids for one-pot synthesis of 1,2,4,5-tetrasubstituted imidazoles, 3,4-dihydropyrimidin-2(1H)- ones and for Michael addition of indole to α,β-unsaturated ketones
-
Novel Lewis acid catalysts were prepared from sulfonated carbon/silica composites derived from starch and silica by treatment with Lewis acids AlCl3, SbCl3, Bi(NO3)3, ZnCl 2 and FeCl3. The catalytic activity of the Lewis acids was evaluated for one-pot synthesis of 1,2,4,5-tetrasubstituted imidazoles, 3,4-dihydropyrimidin-2(1H)-ones and for Michael addition of indole to α,β-unsaturated ketones. Different Lewis acids were investigated with a view to select the most effective solid Lewis acid for organic synthesis. All the Lewis acid catalysts were characterized by FTIR, XRD and AAS analysis and the most active catalyst CSC-Star-SO3-AlCl2 was also characterized by TGA, SEM and TEM.
- Gupta, Princy,Paul, Satya
-
experimental part
p. 75 - 80
(2012/02/02)
-
- Cyclic phosphoric acid catalyzed one-pot, four-component synthesis of 1,2,4,5-tetrasubstituted imidazoles
-
Cyclic phosphoric acid catalyzed one-pot, four component reactions of benzil, aldehydes, primary amines and ammonium acetate in refluxing ethanol were developed, giving highly substituted imidazoles in excellent yield.
- Wang, Xiang Bo,He, Lin,Jian, Teng Yue,Ye, Song
-
experimental part
p. 13 - 16
(2012/03/26)
-