- Rate Constants for Reaction of 1,2-Dimethylimidazole with Benzyl Bromide in Ionic Liquids and Organic Solvents
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The rate constant for the Menschutkin reaction of 1,2-dimethylimidazole with benzyl bromide to produce 3-benzyl-1,2-dimethylimidazolium bromide was determined in a number of ionic liquids and molecular organic solvents. The rate constants in 12 ionic liquids are in the range of (1.0-3.2) × 10 -3 L mol-1 s-1 and vary with the solvent anion in the order (CF3SO2)2N- 6- 4-. Variations with the solvent cation (butylmethylimidazolium, octylmethylimidazolium, butyldimethylimidazolium, octyldimethylimidazolium, butylmethylpyrrolidinium, and hexyltributylammonium) are minimal. The rate constants in the ionic liquids are comparable to those in polar aprotic molecular solvents (acetonitrile, propylene carbonate) but much higher than those in weakly polar organic solvents and in alcohols. Correlation of the rate constants with the solvatochromic parameter ET(30) is reasonable within each group of similar solvents but very poor when all the solvents are correlated together, Better correlation is obtained for the organic solvents by using a combination of two parameters, π* (dipolarity/polarizibility) and α (hydrogen bond acidity), while additional parameters such as δ (cohesive energy density) do not provide any further improvement.
- Skrzypczak,Neta
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- Synthesis of new hetero-arylidene-9(10H)-anthrone derivatives and their biological evaluation
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New hetero-arylidene-9(10H)-anthrone derivatives (1) were synthesized from reaction of 1,2-dimethyl-3-alkyl imidazolium salts (2) and 9-anthracenecarboxaldehyde. Ion exchange of the anion with dioctyl sulfosuccinate and lithium bis(trifluoromethanesulfonyl)imide led to the preparation of other derivatives. The antiproliferative effect of the compounds was evaluated in human ovarian (A2780) and colorectal (HCT116) carcinoma cell lines and in normal primary human fibroblasts. Compound 1 presented an antiproliferative effect related to the imidazolium pattern of substitution with compounds having a decyl group at the R-position (1c and 3c) showing the highest cytotoxic activities in all cell lines independently of the counter ion. Compounds 1b and 1c internalize A2780 cancer cells via a passive or an active transport, respectively, inducing A2780 cell death via an extrinsic apoptosis (1b) or intrinsic apoptosis and oncosis (1c). The localization of both compounds in the cytoplasm coupled to the absence of reactive oxygen species (ROS) induction suggest that the mechanisms of toxicity might be different than those of other anthracyclines currently used in chemotherapy.
- Baptista, Pedro V.,Branco, Paula S.,Fernandes, Alexandra R.,Malta, Gabriela,Peixoto, Daniela,Roma-Rodrigues, Catarina,Ferreira, Luísa M.
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- Alkali stability excellent imidazole and imidazolium cation
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and membranes and devices comprising the polymers. Also provided are methods of making the inventive compounds and polymers.
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Paragraph 0243-0244; 0296-0298
(2018/04/13)
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- Synthesis and Characterization of 1,2-Dimethyl Imidazolium Ionic Liquids and Their Catalytic Activities
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The synthesis of substituted imidazolium-type ionic liquids via a simple method is described. Our synthesized ionic liquids are more useful in the catalytic behavior of the Mannich reaction.
- Ganapathi, Pandurangan,Ganesan, Kilivelu
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supporting information
p. 2135 - 2141
(2015/09/01)
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- Imidazolium Cations with Exceptional Alkaline Stability: A Systematic Study of Structure-Stability Relationships
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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.
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supporting information
p. 8730 - 8737
(2015/07/27)
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- Convenient syntheses of bulky group containing imidazolium ionic liquids
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We report syntheses of bulky group containing imidazolium based ionic liquids. The bulky groups were introduced at N-1, C-2, and N-3 positions of the imidazole ring using convenient methodologies. Copyright
- Kumar, Neeraj,Jain, Rahul
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experimental part
p. 370 - 374
(2012/06/04)
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