- Synthesis and antiproliferative activity of ammonium and imidazolium ionic liquids against T98G brain cancer cells
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Four ammonium and imidazolium ionic liquids (ILs) have been synthesized and screened against the T98G cell line (brain cancer) and HEK normal cells. Treatment induced metabolic cell death (MTT), growth inhibition, clonogenic inhibition were studied as cellular response parameters. Treatment with ILs enhanced growth inhibition and cell death in a concentration dependent manner in both the T98G and HEK cell lines. At higher concentrations (>0.09 mg/mL) the cytotoxic effects of the ILs were highly significant. An inhibitory effect on clonogenic capacity was also observed after cell treatment. Amongst all ILs IL 4 (BMIMCl) exhibited potent activity against T98G brain cancer cells. Despite potent in-vitro activity, all ILs exhibited less cytotoxicity against the normal human HEK cells at all effective concentrations.
- Kaushik, Nagendra Kumar,Attri, Pankaj,Kaushik, Neha,Choi, Eun Ha
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- Ionic Liquid-catalyzed green protocol for Multi-component synthesis of dihydropyrano[2,3-c]pyrazoles as potential anticancer scaffolds
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A series of 6-amino-4-substituted-3-methyl-2,4-dihydropyrano[2,3-c]pyrazole-5-carbonitriles 5a–j were synthesized via one-pot, four-component condensation reactions of aryl aldehydes 1a–j, propanedinitrile (2), hydrazine hydrate (3) and ethyl acetoacetate (4) under solvent-free conditions. We report herein the use of the Br?nsted acid ionic liquid (BAIL) triethylammonium hydrogen sulphate [Et3NH][HSO4] as catalyst for this multi-component synthesis. Compared with the available reaction methodology, this new method has consistent advantages, including excellent yields, a short reaction time, mild reaction conditions and catalyst reusability. Selected synthesized derivatives were evaluated for in vitro anticancer activity against four human cancer cell lines viz. melanoma cancer cell line (SK-MEL-2), breast cancer cell line(MDA-MB-231), leukemia cancer cell line (K-562) and cervical cancer cell line (HeLa). Compounds 5b, 5d, 5g, 5h and 5j exhibited promising anticancer activity against all selected human cancer cell lines, except HeLa. Molecular docking studies also confirmed 5b and 5d as good lead molecules. An in silico ADMET study of the synthesized anticancer agents indicated good oral drug-like behavior and Non-toxic nature.
- Nimbalkar, Urja D.,Seijas, Julio A,Vazquez-Tato, Maria Pilar,Damale, Manoj G,Sangshetti, Jaiprakash N,Nikalje, Anna Pratima G
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- Inexpensive ionic liquids: [HSO4]--based solvent production at bulk scale
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Through more than two decades' intensive research, ionic liquids (ILs) have exhibited significant potential in various areas of research at laboratory scales. This suggests that ILs-based industrial process development will attract increasing attention in the future. However, there is one core issue that stands in the way of commercialisation: the high cost of most laboratory-synthesized ILs will limit application to small-scale, specialized processes. In this work, we evaluate the economic feasibility of two ILs synthesized via acid-base neutralization using two scenarios for each: conventional and intensification processing. Based upon our initial models, we determined the cost price of each IL and compared the energy requirements of each process option. The cost prices of triethylammonium hydrogen sulfate and 1-methylimidazolium hydrogen sulfate are estimated as $1.24 kg -1 and $2.96-5.88 kg-1, respectively. This compares favourably with organic solvents such as acetone or ethyl acetate, which sell for $1.30-$1.40 kg-1. Moreover, the raw materials contribute the overwhelming majority of this cost and the intensified process using a compact plate reactor is more economical due to lower energy requirements. These results indicate that ionic liquids are not necessarily expensive, and therefore large-scale IL-based processes can become a commercial reality. This journal is the Partner Organisations 2014.
- Chen, Long,Sharifzadeh, Mahdi,Mac Dowell, Niall,Welton, Tom,Shah, Nilay,Hallett, Jason P.
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- Quantitative glucose release from softwood after pretreatment with low-cost ionic liquids
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Softwood is an abundantly available feedstock for the bio-based industry. However, achieving cost-effective sugar release is particularly challenging, owing to its guaiacyl-only lignin. Here, we report the highly effective pretreatment of the softwood pine (Pinus sylvestris) using ionoSolv pretreatment, a novel ionic liquid-based lignocellulose fractionation technology. Three protic, low-cost ionic liquids, 1-butylimidazolium hydrogen sulfate, triethylammonium hydrogen sulfate and N,N-dimethylbutylammonium hydrogen sulfate, were used to fractionate the biomass into a carbohydrate-rich pulp and a lignin. The carbohydrate-rich pulp was hydrolysed into fermentable sugars by enzymatic saccharification. Under the most successful pretreatment conditions, quantitative glucose release from the pulp was achieved, which equates to a projected glucose release of 464 mg per gram of pine wood entering the process. We further intensified the process by increasing the solid to solvent ratio up to 1:2 g g-1 while maintaining saccharification yields of 75% of the theoretical maximum. We also demonstrate for the first time that N,N-dimethylbutylammonium hydrogen sulfate, [DMBA][HSO4], is an excellent low-cost pretreatment solvent, surpassing the pretreatment effectiveness of its symmetrically substituted analogue triethylammonium hydrogen sulfate. This shows that ionoSolv pretreatment with protic hydrogen sulfate ionic liquids is a truly feedstock-independent pretreatment option, further increasing the commercial potential of this pretreatment technology.
- Gschwend, Florence J. V.,Chambon, Clementine L.,Biedka, Marius,Brandt-Talbot, Agnieszka,Fennell, Paul S.,Hallett, Jason P.
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- Lignin oxidation and depolymerisation in ionic liquids
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The depolymerisation of lignin directly in the black liquor was studied, comparing two ionic liquids as extracting solvents (butylimidazolium hydrogen sulphate and triethylammonium hydrogen sulphate), under oxidising conditions. H2O2
- Prado,Brandt,Erdocia,Hallet,Welton,Labidi
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- Aiding the versatility of simple ammonium ionic liquids by the synthesis of bioactive 1,2,3,4-tetrahydropyrimidine, 2-aminothiazole and quinazolinone derivatives
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Simple ammonium ionic liquids [ILs] are efficient, green, environmentally friendly catalysts in promoting the Biginelli condensation reaction, Hantzsch reaction and Niementowski reaction to afford 1,2,3,4-tetrahydropyrimidine, 2-aminothiazole and quinazolinone derivatives respectively by eliminating the need for harmful volatile organic solvents. These [ILs] are air and water stable, easy to prepare and cost-effective. The effects of the anions and cations present in [IL] on reactions were investigated. The results clearly indicated that the Biginelli condensation reaction, Hantzsch reaction and Niementowski reaction were heavily influenced by the acidity of [IL], and among various ammonium ionic liquids, [Et3NH][HSO4] showed the best catalytic activity. Furthermore, [IL] could be easily separated and reused with a slight loss of its activity. This technique provided a good alternative way for the industrial synthesis of 1,2,3,4-tetrahydropyrimidinones, 2-aminothiazoles and quinazolinones. The present processes are eco-friendly methods for the synthesis of these derivatives authenticated by several green parameters, namely,E-factor, process mass intensity, reaction mass efficiency, atom economy, and carbon efficiency.
- Kakati, Praachi,Singh, Preeti,Yadav, Priyanka,Awasthi, Satish Kumar
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p. 6724 - 6738
(2021/04/22)
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- ACESULFAME POTASSIUM COMPOSITIONS AND PROCESSES FOR PRODUCING SAME
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A process for producing acesulfame potassium, the process comprising the steps of providing a cyclizing agent composition comprising a cyclizing agent and a solvent and having an initial temperature, cooling the cyclizing agent composition to form a cooled cyclizing agent composition having a cooled temperature less than 35° C., reacting an acetoacetamide salt with the cyclizing agent in the cooled cyclizing agent composition to form a cyclic sulfur trioxide adduct composition comprising cyclic sulfur trioxide adduct; and, forming from the cyclic sulfur trioxide adduct in the cyclic sulfur trioxide adduct composition the finished acesulfame potassium composition comprising non-chlorinated acesulfame potassium and less than 39 wppm 5-chloro-acesulfame potassium. The cooled temperature is at least 2° C. less than the initial temperature.
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Paragraph 0172; 0173; 0174
(2018/04/13)
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- Triethylammonium-based protic ionic liquids with sulfonic acids: Phase behavior and electrochemistry
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Six triethylammonium-based protic ionic liquids (PILs) and two molten salts were synthesized via a proton transfer reaction from sulfonic acid to triethylamine (TEA). The PILs were characterized by 1H NMR, 13C NMR, 1H/15N NMR and FT-IR spectroscopic methods. The phase behavior of the PILs was studied using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The temperature dependences of the PILs electrical conductivity, viscosity, and electrochemical stability window (ECW) were studied. The highest electrical conductivity and ECW values are registered in triethylammonium triflate. The thermal and electrochemical characteristics of the salts obtained in this work have been analyzed in comparison with the literature data by the properties of triethylammonium-based salts with sulfonic acids.
- Shmukler,Gruzdev,Kudryakova,Fadeeva, Yu A.,Kolker,Safonova
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p. 139 - 146
(2018/06/26)
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- Rapid pretreatment of: Miscanthus using the low-cost ionic liquid triethylammonium hydrogen sulfate at elevated temperatures
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Deconstruction with low-cost ionic liquids (ionoSolv) is a promising method to pre-condition lignocellulosic biomass for the production of renewable fuels, materials and chemicals. This study investigated process intensification strategies for ionoSolv pretreatment of Miscanthus × giganteus with the low-cost ionic liquid triethylammonium hydrogen sulfate ([TEA][HSO4]) in the presence of 20 wt% water, using high temperatures and a high solid to solvent loading of 1:5 g/g. The temperatures investigated were 150, 160, 170 and 180 °C. We discuss the effect of pretreatment temperature on lignin and hemicellulose removal, cellulose degradation and enzymatic saccharification yields. We report that very good fractionation can be achieved across all investigated temperatures, including an enzymatic saccharification yield exceeding 75% of the theoretical maximum after only 15 min of treatment at 180 °C. We further characterised the recovered lignins, which established some tunability of the hydroxyl group content, subunit composition, connectivity and molecular weight distribution in the isolated lignin while maintaining maximum saccharification yield. This drastic reduction of pretreatment time at increased biomass loading without a yield penalty is promising for the development of a commercial ionoSolv pretreatment process.
- Gschwend, Florence J. V.,Malaret, Francisco,Shinde, Somnath,Brandt-Talbot, Agnieszka,Hallett, Jason P.
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p. 3486 - 3498
(2018/08/07)
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- Simple protic ionic liquid [Et3NH][HSO4] as a proficient catalyst for facile synthesis of biscoumarins
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Abstract: We have explored a number of protic ionic liquids (PILs) as a catalyst for the synthesis of biscoumarins by condensation of 4-hydroxycoumarin with an aromatic aldehyde. Methylimidazolium- and triethylammonium-based PILs were synthesized by simple neutralization reaction with protic acids. Triethylammonium hydrogen sulfate [Et3NH][HSO4] was found to be the best among the studied PILs concerning the yield of products and reaction time period. Different biscoumarin derivatives were synthesized based on 4-hydroxycoumarin and various substituted aromatic aldehydes at optimum reaction conditions. Obtained products were separated just by simple filtration. The facile method does not require additional purification for formed products. The catalyst has shown better yields along with outstanding recyclability, providing an environmental benign protocol for the synthesis of biscoumarin derivatives. Graphical Abstract: Screening of simple protic ionic liquids as a catalyst in the synthesis of biscoumarins, out of which [Et3NH][HSO4] was found to be best among the studied PILs.
- Patil, Sandip K.,Awale, Deepak V.,Vadiyar, Madagonda M.,Patil, Suryakant A.,Bhise, Sagar C.,Kolekar, Sanjay S.
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p. 5365 - 5376
(2017/09/23)
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- One-pot integrated biofuel production using low-cost biocompatible protic ionic liquids
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The transformation of biomass into liquid fuels is of great importance. Previous work has demonstrated the capability of specific ionic liquids (ILs), such as 1-ethyl-3-methylimidazolium acetate ([C2C1Im][OAc]) and cholinium lysinate ([Ch][Lys]), to be effective biomass pretreatment solvents. Using these ILs for an integrated biomass-to-biofuel configuration is still challenging due to a significant water-wash related to the high toxicity of [C2C1Im][OAc] and pH adjustment prior to saccharification for the highly basic [Ch][Lys]. In this work, we demonstrate, for the first time, that a one-pot integrated biofuel production is enabled by a low cost (~$1 per kg) and biocompatible protic IL (PIL), ethanolamine acetate, without pH adjustments, water-wash and solid-liquid separations. After pretreatment, the whole slurry is directly used for simultaneous saccharification and fermentation (SSF) with commercial enzyme cocktails and wild type yeast strains, generating 70% of the theoretical ethanol yield (based on switchgrass). The structure-performance relationships of PILs in terms of lignin removal, net basicity, and pH value are systematically studied. A technoeconomic analysis (TEA) revealed that an integrated biorefinery concept based on this PIL process could potentially reduce the minimum ethanol selling price by more than 40% compared to scenarios that require pH adjustment prior to SSF. Improvement of the economic performance will be made by reducing the dilution and enzyme loading during SSF as identified by TEA. This study demonstrates the impact of a biocompatible IL in terms of process optimization and conversion efficiency, and opens up avenues for realizing an IL based efficiently integrated biomass conversion technology.
- Sun, Jian,Konda, N. V. S. N. Murthy,Parthasarathi, Ramakrishnan,Dutta, Tanmoy,Valiev, Marat,Xu, Feng,Simmons, Blake A.,Singh, Seema
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p. 3152 - 3163
(2017/07/15)
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- Ir/C and Brφnsted acid functionalized ionic liquids an efficient catalytic system for hydrogenation of nitrobenzene to: P -aminophenol
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In this study, we found that the phenylhydroxylamine intermediate could desorb more easily from an Ir surface than from a Pt surface, which is beneficial for inhibiting the over-hydrogenation of phenylhydroxylamine to aniline. On the other hand, the Brφnsted acid functionalized ionic liquids with sulfonic acid and bisulfate anions were acidic enough to catalyze the Bamberger rearrangement to form p-aminophenol from phenylhydroxylamine. On this basis, a new catalytic system constructed by Ir/C and Brφnsted acid functionalized ionic liquid was applied, for the first time, to the one-pot hydrogenation of nitrobenzene to p-aminophenol. Our results indicate that the PAP selectivity of Ir/C and [SO3H-bmim][HSO4] Brφnsted functionalized ionic liquid was far more than that of the traditional Pt/C and sulfuric acid catalyst system. Furthermore, the dually functionalized ionic liquid ([HSO3-b-N-Bu3][HSO4]) can be used simultaneously as an acid catalyst and also as a surfactant, due to its higher lipophilicity. Therefore, our new catalytic system has unique advantages in the hydrogenation of nitrobenzene to p-aminophenol.
- Wang, Hong,Jiang, Taotao,Ma, Lei,Wang, Hanbing,Xu, Xiaoliang,Lu, Chunshan,Li, Xiaonian
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p. 31663 - 31670
(2017/07/07)
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- Greener approach: Ionic liquid [Et3NH][HSO4]-catalyzed multicomponent synthesis of 4-arylidene-2-phenyl-5(4H)oxazolones under solvent-free condition
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We have developed simple, greener, safer multicomponent synthesis series of 4-arylidene-2-phenyl-5(4H) oxazolones 4(a-r) catalyzed by Bronsted acid ionic liquid as triethylammonium hydrogen sulfate [Et3NH][HSO4] and catalytic amount of acetic anhydride and sodium acetate with excellent yields (90–99%). The protocol offers economical, environmentally benign, solvent-free conditions, and recycle–reuse of the catalyst and easily available starting as benzoyl chloride 1, amino acid 2 and a variety of aldehydes 3. The cyclization followed by condensation of benzoyl chloride, amino acid, and a variety of aldehydes catalyzed by ILs [Et3NH][HSO4] and catalytic amount of acetic anhydride and sodium acetate. The final products were confirmed by their characterization data such as FTIR, 1H-NMR, 13C-NMR, Mass, high-resolution mass spectra and were compared with its reported method.
- Jadhav, Santosh A.,Sarkate, Aniket P.,Farooqui, Mazahar,Shinde, Devanand B.
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p. 1676 - 1683
(2017/09/08)
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- A method of synthesizing triformol (by machine translation)
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The present invention provides a method of synthesizing triformol. The method comprises use of an ionic liquid as a solvent and catalyst, the use of a solid poly-formaldehyde as raw materials, in the 30 °C -150 ° C reaction 0.1h -5h the step of synthesizing triformol, wherein the amount of the solid poly-formaldehyde into the ionic liquid and solid paraformaldehyde of the total mass of the 80% the following. The method provided by the invention is the use of a solid poly-formaldehyde as raw materials, ionic liquid as the solvent and the catalyst, will not produce by-products methyl formate, such as methanol and METHYLAL, can significantly improve the yield of balance trioxymethylene , the energy consumption can be reduced, and the ionic liquid can be repeatedly used, so as to reduce the production cost. (by machine translation)
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Paragraph 0109-0111
(2017/01/26)
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- [Et3NH][HSO4] catalyzed efficient synthesis of 5-arylidene-rhodanine conjugates and their antitubercular activity
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Abstract: We have described a highly efficient, safer protocol for the synthesis of 5-arylidene-rhodanine conjugates catalyzed by Bronsted acidic ionic liquid [Et3NH][HSO4] in excellent yields. The protocol offers cost-effective, environmentally benign, solvent-free conditions and recycle–reuse of the catalyst. The synthesized 5-arylidene-rhodanine conjugates were characterized on the basis of 1H NMR, 13C NMR and HRMS spectral data. A series of 5-arylidene-rhodanine derivatives 3a–h, 4a–h were synthesized and evaluated for their in vitro antitubercular activity against dormant Mycobacterium tuberculosis H37Ra and M. bovis BCG strains. Moreover, compounds 3a, 3b, 3e, 3f, 3g, 3h and 4f exhibited good antitubercular activity and were also evaluated for anti-proliferative activity against MCF-7, A549 and HCT116 cell lines using modified MTT assay and found to be noncytotoxic. Compounds 3a–h and 4f were further screened for their antibacterial activity against four bacteria strains to assess their selectivity towards M. tuberculosis. Furthermore, in silico ADME prediction of all the tested compounds followed the criteria for orally active drug and, therefore, these compounds may have a good potential for eventual development as oral agents. Graphical Abstract: [Figure not available: see fulltext.]
- Subhedar, Dnyaneshwar D.,Shaikh, Mubarak H.,Nawale, Laxman,Yeware, Amar,Sarkar, Dhiman,Shingate, Bapurao B.
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p. 6607 - 6626
(2016/07/12)
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- Facile synthesis of 1,3-thiazolidin-4-ones as antitubercular agents
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We have developed, highly efficient, one-pot, solvent-free, [Et3NH][HSO4] catalyzed multicomponent reaction protocol for the synthesis of 1,3-thiazolidin-4-ones in excellent yields. For the first time, the 1,3-thiazolidin-4-ones were evaluated in vitro for their antimycobacterial activity against Mycobacterium tuberculosis dormant MTB H37Ra and Mycobacterium bovis BCG strains. Among the synthesized basic 1,3-thiazolidin-4-ones, particularly the compounds 4c, 4d, 4e, 4f, 4h, 4i and 4j displays promising antitubercular activity along with no significant cytotoxicity against the cell lines MCF-7, A549 and HCT-116.
- Subhedar, Dnyaneshwar D.,Shaikh, Mubarak H.,Arkile, Manisha A.,Yeware, Amar,Sarkar, Dhiman,Shingate, Bapurao B.
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supporting information
p. 1704 - 1708
(2016/07/27)
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- Highly efficient and recyclable alkylammonium hydrosulfate catalyst for formation of bisphenol F by condensation of phenol with formaldehyde
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Several C1-C4 alkylammonium hydrosulfates [R3NH][HSO4] have been conveniently prepared from the cheap raw materials sulfuric acid and alkylamines. Their acidities were measured by chemical titration and determined using UV-vis spectroscopy with a basic indicator 4-nitroaniline. The catalytic performance of these hydrosulfates for the condensation of phenol with formaldehyde to bisphenol F (BPF) was evaluated in detail on a batch reactor. The results indicated that the proposed catalysts are very active for such condensation due to its homogeneous catalysis characteristics in reaction conditions. Among the catalysts examined, [H3NCH2CH2NH3][HSO4]2 shows the best catalytic performance and it can achieve a complete conversion of formaldehyde, providing a higher than 90% selectivity for BPF under the optimal conditions. Furthermore, the catalyst can be recovered from the reaction mixture via an azeotropic distillation with cyclohexane to remove water and then filtration and used repeatedly six times almost without loss of activity, showing an excellent reusability. It is suggested that the present catalytic process combines the characteristics of a homogenized reaction and heterogenized recovery so might provide a highly-efficient, environmentally-friendly and low-cost route for synthesis of bisphenol F.
- Xiao, Jiafu,Huang, Hua,Xiang, Weijian,Liao, Wei,Liu, Junyi,She, Xichun,Xu, Qiong,Fu, Zaihui,Kirk, Steven Robert,Yin, Dulin
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p. 92716 - 92722
(2016/10/11)
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- [Et3NH][HSO4]-catalyzed one-pot, solvent-free synthesis and biological evaluation of α-amino phosphonates
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Abstract: A series of dimethyl (phenyl(phenylamino)methyl)phosphonates and novel dimethyl ((phenylamino)(2-(prop-2-yn-1-yloxy)phenyl)methyl)phosphonates as potential antifungal agents were synthesized via one-pot, three-component condensation of aldehydes, amines and trimethyl phosphite in solvent-free conditions using [Et3NH][HSO4] as an efficient, eco-friendly and reusable catalyst. Compared to other methods, this new method consistently has advantages, including excellent yields, a short reaction time, mild reaction conditions and catalyst reusability. The newly synthesized propargylated ether containing α-amino phosphonates were evaluated for antifungal and antioxidant activity and were also analyzed for absorption, distribution, metabolism and excretion (ADME) properties. Graphical Abstract: [Figure not available: see fulltext.]
- Shaikh, Mubarak H.,Subhedar, Dnyaneshwar D.,Kalam Khan, Firoz A.,Sangshetti, Jaiprakash N.,Shingate, Bapurao B.
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p. 5115 - 5131
(2016/07/06)
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- Solvent-free, [Et3NH][HSO4] catalyzed facile synthesis of hydrazone derivatives
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In the present study, a library of hydrazone analogues 2(a-j) and 4(a-e) were synthesized, which were typically accessed via a solvent-free facile nucleophilic addition between hydrazine hydrate and appropriately substituted aromatic aldehydes 1(a-j) and 3-formylchromones 3(a-e). The molecular structure of compound (2f) was well supported by single crystal X-ray crystallographic analysis and also verified by DFT calculations. This new synthetic, eco-friendly, sustainable protocol resulted in a remarkable improvement in the synthetic efficiency (90-98% yield), high purity, using [Et3NH][HSO4] as a catalyst and an environmentally benign solvent eliminating the need for a volatile organic solvent and additional catalyst. This ionic liquid is air and water stable and easy to prepare from cheap amine and acid. The present methodology is a green protocol offering several advantages such as, excellent yield of products, minimizing production of chemical wastes, shorter reaction profile, mild reaction conditions, simple operational procedure, easy preparation of catalyst and its recyclability up to five cycles without any appreciable loss in catalytic activity. The optimization conditions carried out in the present study revealed that 20 mol% of ionic liquid catalyst under solvent-free condition at 120°C are the best conditions for the synthesis of hydrazone derivatives in excellent yields.
- Parveen, Mehtab,Azaz, Shaista,Malla, Ali Mohammed,Ahmad, Faheem,Da Silva, Pedro Sidonio Pereira,Silva, Manuela Ramos
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p. 469 - 481
(2015/02/19)
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- [HSO4]-catalyzed eco-friendly and expeditious synthesis of thiazolidine and oxazolidine derivatives
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The present study reports a facile and green approach for the synthesis of thiazolidine/oxazolidine derivatives 4(a-u) in excellent yields (92-98%) with high purity. The protocol involves a one-pot three-component reaction of substituted 1,3-diketones 1(a-g), cyanates 2(a-c) and ethylchloroacetate (3) in ionic liquid [Et3NH][HSO4] under solvent-free conditions. The notable feature of this pathway is that the ionic liquid possesses both catalytic as well as medium engineering capability in this protocol. Use of [Et3NH][HSO4] as a catalyst and an environmentally benign solvent eliminates the need for a volatile organic solvent and additional catalyst. This ionic liquid is air and water stable and easy to prepare from cheap amine and acid. The present synthetic route is a green protocol offering several advantages, such as excellent yield of products, mild reaction conditions, minimizing chemical waste, shorter reaction time, simple operational procedure, easy preparation of the catalyst and its recyclability up to five cycles without any noticeable loss in catalytic activity. The protocol is applicable to a broad substrate scope. The optimization of conditions carried out in the present study revealed that 20 mol% of ionic liquid catalyst under solvent-free conditions at 120 °C are the best reaction parameters for the synthesis of thiazolidine/oxazolidine derivatives in excellent yields. This journal is
- Malla, Ali Mohammed,Parveen, Mehtab,Ahmad, Faheem,Azaz, Shaista,Alam, Mahboob
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p. 19552 - 19569
(2015/06/01)
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- [Et3NH][HSO4]-mediated functionalization of hippuric acid: an unprecedented approach to 4-arylidene-2-phenyl-5(4H)-oxazolones
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A facile, green and stereoselective approach for the synthesis of azlactones/oxazolones 3(a-q) has been developed. The protocol involves reaction of hippuric acid and substituted heterocyclic/aromatic aldehydes in ionic liquid [Et3NH][HSO4] to yield the desired 4-arylidene-2-phenyl-5(4H)-oxazolones in excellent yields (94-97%) with a high degree of purity. The remarkable feature of this pathway is that the ionic liquid eliminates the use of toxic and expensive acetic anhydride and is endowed with catalytic and medium engineering ability. This eco-friendly approach improved synthetic efficiency (94-97% yield), minimizing the production of chemical waste without using highly toxic reagents for the synthesis and more notably, it promoted the selectivity for Z-azlactones/oxazolones. Density functional theory (DFT) calculations revealed that the Z-isomer of compound 3a is stabilised by 2.32 kcal mol-1 more than the E-isomer. This synthetic scheme possesses diverse applicability and is compatible to a range of functional groups (electron donating/electron withdrawing).
- Parveen, Mehtab,Ahmad, Faheem,Malla, Ali Mohammed,Azaz, Shaista,Silva, Manuela Ramos,Silva, P. S. Pereira
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p. 52330 - 52346
(2015/06/25)
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- Tailoring ionic liquid catalysts: Structure, acidity and catalytic activity of protonic ionic liquids based on anionic clusters, [(HSO4)(H 2SO4)x]- (x = 0, 1, or 2)
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Aiming at inexpensive Bronsted-acidic ionic liquids, suitable for industrial-scale catalysis, a family of protonic ionic liquids based on nitrogen bases and sulfuric acid has been developed. Variation of the molar ratio of sulfuric acid, ?H2SO4, was used to tune acidity. The liquid structure was studied using 1H NMR and IR spectroscopies, revealing the existence of hydrogen-bonded clusters, [(HSO4)(H2SO4)]?, for ?H2SO4 0.50. Acidity, quantified by Gutmann Acceptor Number (AN), was found to be closely related to the liquid structure. The ionic liquids were employed as acid catalysts in a model reaction; Fischer esterification of acetic acid with 1-butanol. The reaction rate depended on two factors; for ?H2SO4 0.50, the key parameter was acidity (expressed as AN value), while for ?H2SO4 0.50 it was the mass transport (solubility of starting materials in the ionic liquid phase). Building on this insight, the ionic liquid catalyst and reaction conditions have been chosen. Conversion values of over 95% were achieved under exceptionally mild conditions, and using an inexpensive ionic liquid, which could be recycled up to eight times without diminution in conversion or selectivity. It has been demonstrated how structural studies can underpin rational design and development of an ionic liquid catalyst, and in turn lead to a both greener and economically viable process.
- Matuszek, Karolina,Chrobok, Anna,Coleman, Fergal,Seddon, Kenneth R.,Swadzba-Kwasny, Malgorzata
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p. 3463 - 3471
(2014/07/08)
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- [HSO4] catalyzed efficient and green synthesis of 1,8-dioxo-octahydroxanthenes
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A simple and efficient procedure for synthesis of 1,8-dioxo- octahydroxanthenes by one-pot condensation of aromatic aldehydes with 5,5-dimethyl-1,3-cyclohexanedione under solvent-free conditions using ionic liquid [Et3NH][HSO4] as catalyst is described. The procedure offers several advantages including cleaner reaction profiles, use of easily available, cheap, recyclable and environmentally benign nature of catalyst, high yields, and simple experimental and work-up procedures.
- Zhou, Zhongqiang,Deng, Xiaocui
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- Ionic liquid enhanced alkylation of iso-butane and 1-butene
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The alkylation of iso-butane with 1-butene was catalyzed by triflic acid (TFOH) coupled with a series of protic ammonium-based ionic liquids (AMILs), and the addition of the AMILs dramatically enhanced the efficiency of TFOH for the alkylation reaction. Up to 85.1% trimethylpentanes (TMP) selectivity and 98 research octane number (RON) were achieved with the optimized TFOH/AMIL catalyst (75 vol.% triflic acid and 25 vol.% triethylammonium hydrogen sulfate), which were much better than that with the commercial H2SO4 catalyst (65% TMP selectivity, 97 RON) and pure triflic acid. The addition of AMILs increased the I/O ratio dissolved in the catalyst system and adjusted the acidity of the TFOH/AMILs catalyst system, which were highly beneficial to the alkylation reaction and resulted in high TMP selectivity and high RON.
- Cui, Peng,Zhao, Guoying,Ren, Hailing,Huang, Jun,Zhang, Suojiang
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- Rapid formation of diphenylmethyl ethers and thioethers using microwave irradiation and protic ionic liquids
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Using microwave irradiation and protic ionic liquids (pIL) as co-solvent and catalyst for the synthesis of several diphenylmethyl ethers was achieved. The desired ethers were isolated simply by filtration through a silica plug to remove the pIL and proceeded in high yields (60-98%). These reactions were extremely rapid (10-30 min) and occurred under mild conditions (80 °C). This protocol was also successfully applied to the synthesis of thioethers.
- Altimari, Jarrad M.,Delaney, Joshua P.,Servinis, Linden,Squire, Jennifer S.,Thornton, Megan T.,Khosa, Simren K.,Long, Benjamin M.,Johnstone, Mark D.,Fleming, Cassandra L.,Pfeffer, Frederick M.,Hickey, Shane M.,Wride, Matthew P.,Ashton, Trent D.,Fox, Bronwyn L.,Byrne, Nolene,Henderson, Luke C.
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supporting information; experimental part
p. 2035 - 2039
(2012/07/17)
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- Rapid and efficient protic ionic liquid-mediated pinacol rearrangements under microwave irradiation
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Several protic ionic liquids were tested as potential mediators for pinacol rearrangements employing microwave irradiation. Using hydrobenzoin as a model substrate, the optimal conditions were found to be heating at 80°C for 5 min using H2SO4:triethylamine as the ionic liquid. A key feature of this reaction was to keep the microwave power low (20 W) to avoid ionic liquid degradation. Application of these conditions to triphenylethylene glycol gave rearrangement products in high yield and purity, while phenylethylene glycol and styrene oxide gave pinacol products that underwent a cascade aldol condensation. These conditions represent an efficient means by which pinacol rearrangements can be carried out while avoiding the use of strong Bronsted acids, high temperatures and extended reaction times. The Royal Society of Chemistry.
- Henderson, Luke C.,Byrne, Nolene
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supporting information; experimental part
p. 813 - 816
(2011/06/20)
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- Density and ultrasonic sound speed measurements for N,N-dimethylformamide with ionic liquids
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To understand the molecular interactions between N,N-dimefhylformamide with two families of ionic liquids, the thermophysical properties such as densities and ultrasonic sound speeds have been measured over the entire composition range at 25 °C under atmospheric pressure. The materials investigated in the present study include two families of ionic liquids, viz., ammonium salts and imidazolium salts. Diethyl ammonium acetate, triethyl ammonium acetate, triethyl ammonium dihydrogen phosphate and triethyl ammonium sulphate are the ammonium salts while 1-benzyl-3-methylimidazolium chloride belongs to the imidazolium family. The intermolecular interactions and structural effects are analyzed on the basis of the measured and derived properties. A qualitative analysis of the results are discussed in terms of the ion-dipole interactions, ion-pair interactions and hydrogen bonding between the ionic liquids and N,N-dimethylformamide molecules.
- Attri, Pankaj,Reddy, P. Madhusudhan,Venkatesu
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experimental part
p. 736 - 742
(2011/01/05)
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- Measurements and molecular interactions for N, N-dimethylformamide with ionic liquid mixed solvents
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To understand the molecular interactions between N,N-dimethylformamide (DMF) with two families of ionic liquids (ILs), we have measured thermophysical properties such as densities and ultrasonic sound velocities (u) over the whole composition range at 25 ?°C under atmospheric pressure. The excess molar volume (VE) and the deviation in isentropic compressibilities (??Ks) were predicted using these properties as a function of the concentration of IL. These results are fitted to the Redlich-Kister polynomials. The materials investigated in the present study included two families of ILs such as ammonium salts and imidazolium salts. Diethylammonium acetate ([Et2NH][CH3COO], DEAA), triethylammonium actetate ([Et3NH][CH3COO], TEAA), triethylammonium dihydogen phosphate ([Et3NH][H2PO4], TEAP), and triethylammonium sulfate ([Et3NH][HSO4], TEAS) are ammonium salts and 1-benzyl-3-methylimidazolium chloride ([Bmim][Cl]) belongs to the imidazolium family. The intermolecular interactions and structural effects were analyzed on the basis of the measured and the derived properties. A qualitative analysis of the results is discussed in terms of the ion-dipole, ion-pair interactions, and hydrogen bonding between ILs and DMF molecules and their structural factors. ? 2010 American Chemical Society.
- Attri, Pankaj,Reddy, P. Madhusudan,Venkatesu,Kumar, Anil,Hofman
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experimental part
p. 6126 - 6133
(2010/10/01)
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- Iodination of alcohols under microwave irradiation using KI in the presence of a catalytic amount of ionic liquid triethylamoniom hydrogensulfate([Et 3NH]+HSO4-)
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The iodination of alcohols with KI in the presence of a catalytic amount of triethylamoniom hydrogensulfate ([Et3NH]+HSO 4-) as a novel and inexpensive ionic liquid under microwave irradiation has been investigated. Copyright Taylor & Francis Group, LLC.
- Hajipour, Abdol R.,Azizi, Ghobad,Ruoho, Arnold E.
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experimental part
p. 242 - 250
(2009/04/07)
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- Process for the preparation of urethanes
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A process for the preparation of urethanes by reacting a tertiary amine, an alcohol and carbon monoxide in the presence of a catalytic quantity of a copper salt, oxygen and a dehydrating agent is disclosed. The reaction is preferably carried out using a copper halide catalyst and dehydrating agents which combine with water to release the alcohol used in the preparation of the urethane product.
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