Chiral Room Temperature Ionic Liquids as Enantioselective Promoters for the Asymmetric Aldol Reaction

González, Laura; Escorihuela, Jorge; Altava, Belén; Burguete, M. Isabel; Luis, Santiago V.

doi:10.1002/ejoc.201402436

Cited by 32 publications

(20 citation statements)

References 65 publications

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“…The imidazole-amino acid derivatives 1a , 2a , and 3a were obtained from the corresponding α-amino amide as previously described [ 31 ]. Monotopic and ditopic -imidazolium salts 1b–3b and 1c–3c were obtained in high yield by treatment of the corresponding imidazole with benzyl bromide or 1,3-bromomethylbenzene, respectively, as described in our previous publications ( Scheme 1 ) [ 30 , 32 ].…”

Section: Resultsmentioning

confidence: 99%

“…In this context, amino acid-based monoimidazolium salts with good bacterial toxicity have been reported in the literature [29]. Our research group has an ongoing interest in the biomimetic and bioactive capacity of imidazole or imidazolium amino acid derivatives [30][31][32][33]. Herein, imidazole, monotopic, and ditopic imidazolium salts derived from L-valine and L-phenylalanine with different alkyl lengths in the amide substitution were synthesized and characterized comprehensively.…”

Section: Synthesismentioning

confidence: 99%

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Imidazole and Imidazolium Antibacterial Drugs Derived from Amino Acids

et al. 2020

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The antibacterial activity of imidazole and imidazolium salts is highly dependent upon their lipophilicity, which can be tuned through the introduction of different hydrophobic substituents on the nitrogen atoms of the imidazole or imidazolium ring of the molecule. Taking this into consideration, we have synthesized and characterized a series of imidazole and imidazolium salts derived from L-valine and L-phenylalanine containing different hydrophobic groups and tested their antibacterial activity against two model bacterial strains, Gram-negative E. coli and Gram-positive B. subtilis. Importantly, the results demonstrate that the minimum bactericidal concentration (MBC) of these derivatives can be tuned to fall close to the cytotoxicity values in eukaryotic cell lines. The MBC value of one of these compounds toward B. subtilis was found to be lower than the IC50 cytotoxicity value for the control cell line, HEK-293. Furthermore, the aggregation behavior of these compounds has been studied in pure water, in cell culture media, and in mixtures thereof, in order to determine if the compounds formed self-assembled aggregates at their bioactive concentrations with the aim of determining whether the monomeric species were in fact responsible for the observed antibacterial activity. Overall, these results indicate that imidazole and imidazolium compounds derived from L-valine and L-phenylalanine—with different alkyl lengths in the amide substitution—can serve as potent antibacterial agents with low cytotoxicity to human cell lines.

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Section: Resultsmentioning

confidence: 99%

Section: Synthesismentioning

confidence: 99%

Imidazole and Imidazolium Antibacterial Drugs Derived from Amino Acids

et al. 2020

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“…ILs are purely ionic materials with generally low, below 100 °C, melting temperatures [ 214 ]. ILs have found applications in a wide variety of fields including their use as green solvents in organic synthesis [ 215 ], catalysis [ 216 , 217 ], extraction, separation [ 218 ], supramolecular chemistry [ 219 , 220 ], transport agents [ 221 ], pharmaceutical chemistry [ 222 ], materials science, and drug sensing [ 223 ], among others. ILs have several favorable properties including their temperature stability, non-volatility and non-flammability, rather high ionic conductivity, and reduced environmental impact.…”

Section: Composite Membranesmentioning

confidence: 99%

Recent Progress in the Development of Composite Membranes Based on Polybenzimidazole for High Temperature Proton Exchange Membrane (PEM) Fuel Cell Applications

et al. 2020

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The rapid increasing of the population in combination with the emergence of new energy-consuming technologies has risen worldwide total energy consumption towards unprecedent values. Furthermore, fossil fuel reserves are running out very quickly and the polluting greenhouse gases emitted during their utilization need to be reduced. In this scenario, a few alternative energy sources have been proposed and, among these, proton exchange membrane (PEM) fuel cells are promising. Recently, polybenzimidazole-based polymers, featuring high chemical and thermal stability, in combination with fillers that can regulate the proton mobility, have attracted tremendous attention for their roles as PEMs in fuel cells. Recent advances in composite membranes based on polybenzimidazole (PBI) for high temperature PEM fuel cell applications are summarized and highlighted in this review. In addition, the challenges, future trends, and prospects of composite membranes based on PBI for solid electrolytes are also discussed.

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“…ILs are promising compounds for the preparation of electrochemical devices because they exhibit high thermal stability, good conductivities and low or even neglected leaching of the bulk IL component has been detected when the ILs is taking part in a polymeric matrix [35,36]. In recent years, the use of ILs as fillers in polymer-based membranes has been deeply studied in gas separation processes [37], drug sensing [38], pharmaceutics and medicine [39], transport agents [40], catalysis [41,42,43], and energy storage and conversion [44,45,46]. ILs offer a significant advantage over phosphoric acid doping as they are highly stable at temperatures higher than 160 °C.…”

Section: Introductionmentioning

confidence: 99%

Ionic Liquid Composite Polybenzimidazol Membranes for High Temperature PEMFC Applications

et al. 2019

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A series of proton exchange membranes based on polybenzimidazole (PBI) were prepared using the low cost ionic liquids (ILs) derived from 1-butyl-3-methylimidazolium (BMIM) bearing different anions as conductive fillers in the polymeric matrix with the aim of enhancing the proton conductivity of PBI membranes. The composite membranes prepared by casting method (containing 5 wt. % of IL) exhibited good thermal, dimensional, mechanical, and oxidative stability for fuel cell applications. The effects of anion, temperature on the proton conductivity of phosphoric acid-doped membranes were systematically investigated by electrochemical impedance spectroscopy. The PBI composite membranes containing 1-butyl-3-methylimidazolium-derived ionic liquids exhibited high proton conductivity of 0.098 S·cm−1 at 120 °C when tetrafluoroborate anion was present in the polymeric matrix. This conductivity enhancement might be attributed to the formed hydrogen-bond networks between the IL molecules and the phosphoric acid molecules distributed along the polymeric matrix.

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Chiral Room Temperature Ionic Liquids as Enantioselective Promoters for the Asymmetric Aldol Reaction

Cited by 32 publications

References 65 publications

Imidazole and Imidazolium Antibacterial Drugs Derived from Amino Acids

Imidazole and Imidazolium Antibacterial Drugs Derived from Amino Acids

Recent Progress in the Development of Composite Membranes Based on Polybenzimidazole for High Temperature Proton Exchange Membrane (PEM) Fuel Cell Applications

Ionic Liquid Composite Polybenzimidazol Membranes for High Temperature PEMFC Applications

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