- New Insights into the Role of Imidazolium-Based Promoters for the Electroreduction of CO2 on a Silver Electrode
-
The electrochemical reduction of CO2 to CO is a reaction of central importance for sustainable energy conversion and storage. Herein, structure-activity relationships of a series of imidazolium-based cocatalysts for this reaction are described,
- Lau, Genevieve P. S.,Schreier, Marcel,Vasilyev, Dmitry,Scopelliti, Rosario,Gr?tzel, Michael,Dyson, Paul J.
-
-
Read Online
- Europium triflate-catalyzed one-pot synthesis of 2,4,5-trisubstituted-1H- imidazoles via a three-component condensation
-
A simple, efficient, and practical procedure for synthesis of 2,4,5-trisubstituted-1H-imidazoles via the condensation of benzoin or acetoin, aromatic aldehydes, and ammonium acetate using europium triflate [Eu(OTf)3] as a novel catalyst in high yields is described. The catalyst can be recovered conveniently and reused at least four times without any loss of activity. Copyright Taylor & Francis Group, LLC.
- Yu, Chuanming,Lei, Min,Su, Weike,Xie, Yuanyuan
-
-
Read Online
- TMSOTf-catalyzed synthesis of trisubstituted imidazoles using hexamethyldisilazane as a nitrogen source under neat and microwave irradiation conditions
-
In the process of drug discovery and development, an efficient and expedient synthetic method for imidazole-based small molecules from commercially available and cheap starting materials has great significance. Herein, we developed a TMSOTf-catalyzed synthesis of trisubstituted imidazoles through the reaction of 1,2-diketones and aldehydes using hexamethyldisilazane as a nitrogen source under microwave heating and solvent-free conditions. The chemical structures of representative trisubstituted imidazoles were confirmed using X-ray single-crystal diffraction analysis. This synthetic method has several advantages including the involvement of mild Lewis acid, being metal- and additive-free, wide substrate scope with good to excellent yields and short reaction time. Furthermore, we demonstrate the application of the methodology in the synthesis of biologically active imidazole-based drugs.
- Asressu, Kesatebrhan Haile,Chan, Chieh-Kai,Wang, Cheng-Chung
-
p. 28061 - 28071
(2021/09/15)
-
- Ferric iron complex containing meta-position carborane ligand as well as preparation method and application of ferric iron complex
-
The invention relates to a ferric iron complex containing a meta-carborane triazole ligand as well as a preparation method and application of the ferric iron complex. The ferric iron complex is prepared by the following steps: (1) dropwise adding an n-BuL
- -
-
Paragraph 0032; 0039-0041; 0042
(2020/10/14)
-
- 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.
-
experimental part
p. 2038 - 2049
(2012/08/27)
-
- Synthesis and photophysics of some novel imidazole derivatives used as sensitive fluorescent chemisensors
-
Some novel imidazole derivatives were developed for highly sensitive chemisensors for transition metal ions. Since these compounds are sensitive to different external stimulations such as UV irradiation, heat, increasing pressure and changing the environm
- Saravanan, Kanagarathinam,Srinivasan, Natesan,Thanikachalam, Venugopal,Jayabharathi, Jayaraman
-
body text
p. 65 - 80
(2012/04/23)
-
- Efficient synthesis of imidazoles from aldehydes and 1,2-Diketones under superheating conditions by using a continuous flow microreactor system under pressure
-
A simple and efficient method for the synthesis of 2,4,5-trisubstituted imidazoles has been developed by using a continuous flow microreactor system under pressure; aryl-, alkyl-, and heteroaryl-substituted imidazoles were obtained in high yields within 2 min under superheating conditions.
- Kong, Lingjie,Lv, Xiaoming,Lin, Qi,Liu, Xiaofeng,Zhou, Yaming,Jia, Yu
-
experimental part
p. 902 - 904
(2011/03/20)
-
- Room temperature synthesis of tri-, tetrasubstituted imidazoles and bis-analogues by mercaptopropylsilica (MPS) in aqueous methanol: application to the synthesis of the drug trifenagrel
-
The heterogeneous solid catalyst, mercaptopropylsilica (MPS), has been prepared by a modified procedure in water and its structure confirmed by solid state carbon-13 CP-MAS NMR spectrum. This catalyst has been efficiently utilized for the synthesis of a w
- Mukhopadhyay, Chhanda,Tapaswi, Pradip Kumar,Drew, Michael G.B.
-
supporting information; experimental part
p. 3944 - 3950
(2010/08/07)
-
- Synthesis and Properties of 4H-Imidazoles
-
The photolysis of 1-vinyltetrazoles to give 1H-imidazoles is extended to the synthesis of isolable nonaromatic 4H-imidazoles when the vinyl group is terminally disubstituted.Thus photolysis of the 2-phenyltetrazole (7a), prepared from isobutyraldehyde, at
- Casey, Michael,Moody, Christopher,Rees, Charles W.
-
p. 1389 - 1394
(2007/10/02)
-
- Photochemical Transformations of 1-Imidazolyl-1,2-dibenzoylalkenes. Steady-State and Laser Flasch Photolysis Investigations
-
The photochemistry of a number of 1-imidazolyl-1,2-dibenzoylalkenes and 1-benzimidazolyl-1,2-dibenzoylalkenes has been investigated by steady-state photolysis combined with product analysis and laser flash photolysis.In several cases, the intramolecular phenyl group migration leading to ketene-mediated 3-butenoic acids and esters is observed.In addition, depending on the substituents present in the imidazolyl and benzimidazolyl groups, a variety of phototransformations occur; these include electrocyclic ring-closure reactions leading to dihydrophenanthrene and dihydroisoquinoline derivatives and photofragmentation reactions resulting in the loss of the imidazolyl moieties from the parent dibenzoylalkenes.Plausible mechanisms for these photoreactions are discussed.Laser flash photolysis in several cases gives rise to transient processes related to ketene and zwitterionic intermediates.
- Barik, Rabindra,Bhattacharyya, Kankan,Das, Paritosh K.,George, Manapurathu V.
-
p. 3420 - 3428
(2007/10/02)
-
- THERMOLYSIS OF 4-AZIDOPYRIMIDINES AND 4-AZIDOQUINAZOLINES
-
A facile thermolysis of 4-azidopyrimidines and 4-azidoquinazolines leading, by ring contraction, in excellent yields to 1-cyanoimidazoles and benzimidazoles is reported.
- Giammanco, Lorenzo,Invidiata, Francesco Paolo
-
p. 1459 - 1464
(2007/10/02)
-
- Biomimetic Models for Cysteine Proteases. 1. Intramolecular Imidazole Catalysis of Thiol Ester Solvolysis: A Model for the Deacylation Step
-
The solvolysis of 2--4,5-dimethylimidazole (3) has been studied in ethanol-water solution as a model for the thiol ester intermediates occurring during the catalytic cycle of cysteine proteases.Additionally the solvolyses of N-acetyl-4,5-dimethyl-2-phenylimidazole (4) and benzenethiolacetate (5) were studied as reference compounds.At neutrality, a plateau in the pH-log kobsdprofile for solvolysis of 3 is seen due to the participation of imidazole.Evidence is given that the mechanism in this region is intramolecular general-base-catalyzed solvent attack on the thiol ester by imidazole.At pHs greater than 10, specific-base-catalyzed solvolysis of the thiol ester becomes predominant.There is no kinetic importance of an S-to-N acyl transfer during the course of solvolysis.The relevance of these results to the chemical mechanism of cysteine proteases is discussed.
- Street, J. P.,Brown, R. S.
-
p. 6084 - 6089
(2007/10/02)
-
- Synthesis and Properties of 4H-Imidazoles
-
Photolysis of alkenyltetrazoles (1) provides the first rational route to simple 4H-imidazoles (2); when unsubstituted at C-5 these are highly reactive towards nucleophiles and rearrange rapidly to the aromatic 1H-imidazoles on heating.
- Casey, Michael,Moody, Christopher J.,Rees, Charles W.
-
p. 1082 - 1083
(2007/10/02)
-