Basic Ionic Liquid Research Articles

Efficient synthesis of pyrano[2,3-d]pyrimidinone and pyrido[2,3-d]pyrimidine derivatives in presence of novel basic ionic liquid catalyst

A basic ionic liquid, namely 1,1′-(butane-1,4-diyl)bis(1,4-diazabicyclo [2.2.2]octan-1-ium) hydroxide, was prepared and characterized using Fourier-transform infrared spectroscopy, 1 H nuclear magnetic resonance spectroscopy, and pH measurements. The ionic liquid was used for efficient promotion of the synthesis of pyrano[2,3- d ]pyrimidinone and pyrido[2,3- d ]pyrimidine derivatives at room temperature under grinding conditions. A simple procedure, short reaction time, high yields, non-column chromatographic separation, commercial availability of the starting materials, and recyclability of the catalyst are attractive features of this process. 1,1′-(Butane-1,4-diyl)bis(1,4-diazabicyclo[2.2.2]octan-1-ium) hydroxide, which is a basic ionic liquid, efficiently promoted the synthesis of pyrano[2,3- d ]pyrimidinones and pyrido[2,3- d ]pyrimidines at room temperature under grinding conditions.

Choline taurinate: a new biocompatible amino-functionalized ionic liquid as basic catalyst and extraction solvent

Abstract A new biocompatible amino-functionalized ionic liquid composed solely of biomaterials was synthesized from taurine and choline hydroxide, and its physical properties (density, viscosity, miscibility and thermal stability) were also determined. The classic base-promoted three-component cyclic condensation of aromatic aldehydes, malononitrile and dimedone was chosen as the test reaction to demonstrate the catalytic activity of choline taurinate ([Ch][Tau]). The catalyst could be recovered and reused several times with no significant loss of activity. As a basic ionic liquid, [Ch][Tau] can extract acidic compounds from immiscible solvents through acid-base interaction. The extraction process of fluorescent dye Rhodamine B was monitored using ultraviolet-visible (UV-Vis) spectroscopy, by which the percentage extraction rate was determined as 95%.

Synthesis of 16α-amino-pregnenolone derivatives via ionic liquid-catalyzed aza-Michael addition and their evaluation as C17,20-lyase inhibitors

Aza-Michael addition of 16-dehydropregnenolone was studied in the presence of a basic ionic liquid, [DBU][OAc] as catalyst and solvent. The reaction was carried out using different primary and secondary amines as N-nucleophiles. The products were obtained in moderate to good yields and were characterized by 1H and 13C NMR, MS and IR. The ionic liquid was found to be an efficient and recyclable catalyst that was reused five times. The products were investigated for the inhibition of in vitro C17,20-lyase activity and displayed moderate inhibitory effect.

Microwave-assisted Domino Cyclization for the Synthesis of Novel Spiro-benzo[a]phenazine Annulated Heterocycles Catalyzed by a Basic Ionic Liquid

An efficient and green strategy for the improved synthesis of a biologically and pharmaceutically interesting multi-functionalized diverse novel spiro-benzo[a]phenazine annulated heterocycles was developed with the assistance of microwave irradiation. A sequential one-pot, two-step domino reaction starting from 2-hydroxynaphthalene-1,4-dione, benzene-1,2-diamines, a cyclic carbonyl compound, and 1,3-indandione in the presence of a basic ionic liquid (1-butyl-3-methylimidazolium hydroxide) as an expedient, ecofriendly and reusable catalyst afforded the corresponding novel spiro[benzo[a]indeno[2′,1′:5,6]pyrano[2,3-c]phenazine] derivatives with high yield under solvent-free conditions. This domino Knoevenagel–Michael annulation reaction provided five new bonds (two C–C, two CN, and one C–O) and two new rings through multiple operations in a single flask.

Facile immobilization of base ionic liquids onto graphene oxide in water at room temperature as heterogeneous catalysts for transesterification

The basic ionic liquids (ILs) 1-(trimethoxysilyl)propyl-3-methylimidazolium hydroxide was immobilized on the surface of graphene oxide (GO) by silanization with the siloxane-terminated ILs in water at room temperature for the first time. The catalytic performances of the GO grafted with the basic ILs were investigated in transesterification reactions. The high catalytic activities and excellent product selectivities of GO grafted with the basic ILs in transesterification reactions can be ascribed to the large amount of ILs on the GO surface. The high dispersibility of GO in water prompted our investigation of grafting of a basic ILs on a GO surface. This method is the most efficient, simple, and green approach for the immobilization of ILs reported to date.

Basic ionic liquid [BMIM][OH] as heterogeneous catalyst mediated solvent-free Stobbe condensation applying grindstone technique for the synthesis of novel β-arylidene-β-benzoylpropionic acid derivatives

The basic ionic liquid 1-butyl-3-methylimidazolium hydroxide, i.e. [BMIM][OH], proficiently catalyzed Stobbe condensation in solvent-free condition. An extensive range of aromatic aldehydes simply undergo condensations with methyl-β-benzoyl propionate. The reactions proceed at room temperature and are very fast (10 min). However, the most crucial feature of this methodology is the solvent-free approach and applying grindstone technique for condensation, which is generally not possible by any other conventional reagents and was not addressed adequately in literature providing a general and convenient procedure. The potential application of [BMIM][OH] in organic synthesis is increasing rapidly due to its high yields of the desired products (80%–92%), minimal reaction time, reaction simplicity, and low-cost chemicals. All novel compounds of β-arylidene-β-benzoylpropionic acid derivatives were characterized by IR, 1H NMR, and mass spectra.

Caffeine catalyzed green synthesis of novel benzo[a][1,3]oxazino[6,5-c]phenazines via a one-pot multi-component sequential protocol in a basic ionic liquid

Caffeine was applied as a green and natural catalyst for the one-pot, four-component sequential condensation between 2-hydroxy-1,4-naphthoquinone, aromatic 1,2-diamines, ammonium thiocyanate and acid chlorides in the presence of a basic ionic liquid (1-butyl-3-methylimidazolium hydroxide) to afford the corresponding benzo[a][1,3]oxazino[6,5-c]phenazine derivatives. In this one-pot transformation, five bonds and two new rings are efficiently formed. This protocol has the advantages of operational simplicity, high yields, easy workup, avoidance of hazardous or toxic catalysts and organic solvents and high chemo- and regioselectivities.

Highly efficient and recyclable basic ionic liquids supported on SBA-15 for the synthesis of substituted styrenes, carbinolamides, and naphthopyrans

In this study, highly stable mesoporous silica, SBA-15, was prepared and used as a support to functionalize ionic liquids. Triazole and N,N-dimethylaminopyridine were functionalized on the surface of SBA-15 through surface silanol groups of SBA-15 to obtain basic ionic liquids. In order to obtain high basicity, −OH containing basic ionic liquids, based on triazole and N,N-dimethylaminopyridine, were prepared. Catalysts were characterized by the complementary combination of low angle powder X-ray diffraction, N2-adsorption, electron microscopes, Fourier-transform infrared spectroscopy, thermal gravimetric analysis, elemental analysis, and temperature programme desorption techniques. Systematic assessment of the catalytic activity was made using Knoevenagel condensation reaction for the synthesis of substituted styrenes. Application of these catalysts was also evaluated in the synthesis of carbinolamides. Recycling study shows that no significant decrease in the catalytic activity was observed after five recycles. Finally, application of the highly active basic ionic liquid was evaluated in one-pot, two-step tandem reaction for the synthesis naphthopyrans.

Taming the Base Catalyzed Sol–Gel Reaction: Basic Ionic Liquid Gels of SiO2 and TiO2

We describe the autocatalytic synthesis of SiO2 and TiO2 ionic liquid gels using a basic ionic liquid as the solvent, template, and catalyst for the sol–gel reaction. Basic gels were synthesized using a two-component mixture of the basic ionic liquid [P66614][OH] and either tetraethylorthosilicate or titanium isopropoxide (Ti(OiPr)4). The gels formed were clear glassy materials. The unstable basic ionic liquid was stabilized by the matrix and showed both increased thermal stability (by thermogravimetric analysis) and chemical stability (by solid-state NMR) after over 1 year of storage.

Highly efficient green synthesis of α-hydroxyphosphonates using a recyclable choline hydroxide catalyst

Aldehydic carbonyl groups are eco-friendly and efficiently hydrophosphonylated by diethylphosphite using the basic ionic liquid, choline hydroxide.

Cyclic Voltammetry and X-ray Absorption Spectroscopy of Nickel Oxide in the Ionic Liquid 1-Ethyl-3-Methyl Imidazolium Chloride/Aluminum Chloride

Transition metal chlorides have been examined in situ in ionic liquids (ILs) using cyclic voltammetry (CV) but the oxides of these metals have not received as much attention. In this study, the structure of nickel oxide in the ionic liquid, 1-ethyl-3-methyl imidazolium chloride (EMIC) and aluminum chloride has been investigated. The NiO in EMIC/AlCl3 IL was examined with CVs and Extended X-ray Absorption Fine Structure (EXAFS) in both Lewis acidic and basic IL solutions. The CV of NiO in both acidic and basic EMIC/AlCl3 ILs shows similarities with the CV of NiCl2 in these ILs. The EXAFS data for the NiO and anhydrous NiCl2 in these acidic and basic IL solutions are also analogous, indicating that some corresponding molecular structures may have formed and these are discussed in detail.

Investigation of morphologies, photoluminescence and photocatalytic properties of ZnO nanostructures fabricated using different basic ionic liquids

ZnO nanostructures were synthesized in methanol-water reaction media using different basic ionic liquids [BILs] by hydrothermal approach at 150°C. ZnO nanoparticles obtained from BILs consists of different morphologies, such as, hexagonal disks, hexagonal rings assembled by nanoparticles, hexagonal disks-aggregated flower-like structure and nanospheres. The effect of these basic ionic liquids on morphology, particle size and properties of as-synthesized ZnO nanostructures was investigated. The obtained nanoparticles have been characterized by X-ray diffraction, TEM, SEM, UV–vis absorption spectroscopy and photoluminescence (PL) studies. The XRD study of as-synthesized ZnO nanostructures confirmed the existence of hexagonal wurtzite structure. The maximum around 371nm was observed in UV–vis absorption spectrum and the calculated band-gap energy is in the range of 3.07-3.10eV. The photoluminescence spectra exhibited blue and blue-green emissions. ZnO nanoparticles prepared in choline hydroxide showed higher photocatalytic activity, which was accounted for due to high surface area, the smaller size of nanoparticles and low electron-hole recombination effect.

Design and synthesis of basic ionic liquids for the esterification of triterpenic acids

We present the design and synthesis of Bronsted-basic ionic liquids and investigate their application in the microwave-assisted esterification of betulinic acid, aiming towards a benign and pyridine-free manufacturing process of the anti-HIV drug, bevirimat.

Structure Evolution of Synthetic Amino Acids-Derived Basic Ionic Liquids for Catalytic Production of Biodiesel

A two-step strategy was attempted to develop the best amino acid-based basic ionic liquids for catalytic production of biodiesel via transesterification. Cholinium with various amino acids as paired anions were first synthesized to screen anionic moiety. Arginine and histidine were selected for further structural evolution by varying the substituents of tetraammonium cation. Tetrabutylammonium arginine ([TBA][Arg]) was found to be the most effective catalyst to obtain 98.0%–99.8% yield of biodiesel at 80 °C within 15 min with catalyst loading of 28.84 mmol/100 g high oleic sunflower oil. 13C NMR spectra of reactants and products certified the progress of transesterification structurally. Biodiesel yield of 98.80% was obtained under the optimal conditions: catalyst loading 6% (oil basis, w/w), temperature 90 °C, methanol to oil mole ratio 9:1, and 15 min reaction. The catalytic transesterification by [TBA][Arg] was applicable for different alkyl alcohols, but the activity decreased with increasing alkyl ch...

Synthesis of Glycerol Carbonate from Glycerol and Dimethyl Carbonate Using Ionic Liquid Catalysts

Acidic, basic and neutral ionic liquids (ILs) were prepared by two-step method. Their IR and NMR spectra showed that their structures were in accordance with their theoretical structure. Then these ILs were used as catalysts in the Glycerol carbonate (GC) of glycerol with dimethyl carbonate (DMC). The results show that basic ILs have high catalytic activity compared with acidic or neutral ILs and inorganic basic catalysts in the reaction. Under the suitable conditions using [Bmin]lm as a catalyst led to the yield of GC reached 94%, glycerol conversion reached 96%, GC selectivity reached 97% at molar ratio of DMC to glycerol at 3: 1, mass fraction of ionic liquid 12% (omega), reaction temperature 80 degrees C and reaction time 70 min. The ionic liquid was stable, and its activity did not decrease after using for 8 times (i. e., 85% glycerol conversion and near 90% GC selectivity). The results showed that the basic ionic liquid is more ideal green catalyst in esterification reaction.

ChemInform Abstract: Basic Ionic Liquid as Catalyst and Reaction Media for the One‐Pot Three‐Component Regioselective Synthesis of Various Thiazol‐2‐imine Derivatives.

AbstractThe catalyst‐free condensation reaction between alkylisothiocyanates, α‐haloketones and aryl amines delivers the products in often very high yields.

Computer-Assisted Design of Ionic Liquids for Efficient Synthesis of 3(2H)-Furanones: A Domino Reaction Triggered by CO2

A strategy for the highly efficient synthesis of 3(2H)-furanones by hydration of diyne alcohols catalyzed by base-functionalized ionic liquids under atmospheric-pressure CO2 that was developed through computer-assisted design is reported. The best range of basic ionic liquids as catalysts was predicted at first, and [HDBU][BenIm] exhibited the highest catalytic activity. Through a combination of NMR spectroscopic investigations and quantum-chemical calculations, the results indicated the importance of the basicity of the anion and the species of cation in the ionic liquid.

Introduction of a novel basic ionic liquid containing dual basic functional groups for the efficient synthesis of spiro-4H-pyrans

In this research the synthesis of 1,1′-(butane-1,4-diyl)bis(1,4-diazabicyclo[2.2.2]octan-1-ium) hydroxide as an effective basic ionic liquid containing dual basic functional groups is reported. After characterization using FT-IR, 1H NMR, 13C NMR and mass analyses, this reagent is efficiently used for promotion of the synthesis of spiro-4H-pyrans via one-pot three-component condensation through a domino Knoevenagel/Michael/cyclization sequence. The attractive features of this process are simple procedure, short reaction times, high yields, no column chromatographic separation, commercial availability of the starting materials and recyclability of the catalyst.

One-pot cis-selective route to sugar-fused thiazines via a masking–unmasking strategy in basic ionic liquid

A novel sequential Knoevenagel condensation, thia-Michael, and amino/mercaptoacetylative ring transformation reaction cascade for cis-selective synthesis of sugar-fused 1,3-thiazine is reported. The expeditious one-pot multicomponent annulation was performed using masked amino acid viz. 2-phenyl-1,3-oxazol-5-one or masked mercaptoacid viz. 2-methyl-2-phenyl-1,3-oxathiolan-5-one, d-xylose/d-glucose, and N-aryldithiocarbamic acid in ionic liquid [bmim]OH. The acetophenone obtained as a by-product and [bmim]OH itself could be easily recycled for further use without loss of efficiency. The envisaged method is operationally simple, high yielding, and excellent diastereoselective in favor of the cis-isomer of fused thiazines.

ChemInform Abstract: Metal‐Free Synthesis of 1,2,3‐Triazoles by Azide—Aldehyde Cycloaddition under Ultrasonic Irradiation in TSIL [DBU‐Bu]OH and in Hydrated IL Bu4NOH under Heating.

Efficient and environmentally benign procedures have been reported for the synthesis of 1,4-disubstituted 1,2,3-triazoles by reaction of aryl azides with aldehydes in task-specific basic ionic liquid [DBU-Bu]OH under ultrasonic irradiation and in hydrated ionic liquid tetrabutylammonium hydroxide (Bu4NOH) under conventional heating. These protocols represent simple, general, and efficient approaches in terms of good yields, operational simplicity, easy workup, and shorter reaction time for the synthesis of 1,4-disubstituted 1,2,3-triazoles under metal-free conditions.