A new route to the synthesis of isoxazoline derivatives from dihydropyran via cycloaddition reaction in ionic liquid

A new approach to the synthesis and 1,3-dipolar cycloadditions of nitrones has been described from 2,3-dihydro-4H-pyran and various hydroxylamines, with electron-deficient alkynes for the synthesis of isoxazoline derivatives. Significant rate acceleration and improved yields of exclusively exo isoxazolines in 1-butyl-3-methylimidazolium based ionic liquids have been observed. Novel isoxazolines may be used as a precursor for the synthesis of variety of peptides.     

A novel synthesis of pyrazolo[3,4-b]pyridine derivatives through multi-component reaction in ionic liquid

An efficient and novel procedure for the preparation of pyrazolo[3,4-b]pyridine derivatives through multi-component reaction of aldehyde, 5-amino-3-methyl-1-phenylpyrazole and malononitrile or cyanoacetate in [bmim][BF4] is described in this paper. Advantages of the method presented here include mild conditions, high yields together with a green nature and ease of recovery and reuse of the reaction medium.     

Synthesis of benzofurans in ionic liquid by a PdCl2-catalyzed intramolecular Heck reaction

PdCl₂-catalyzed intramolecular Heck reaction was conducted in ionic liquid, 1-n-butyl-3-methylimidazolium tetraborate ([BMIm] BF₄), substituted benzofurans were obtained in modest to satisfactory yields. The ionic liquid containing Pd catalyst can be used four times with a little loss of activity.     

Chiral ionic liquid-catalyzed Biginelli reaction: stereoselective synthesis of polyfunctionalized perhydropyrimidines

A chiral ionic liquid-catalyzed, efficient and unprecedented version of the Biginelli reaction using new variants of its active methylene component, viz. 2-phenyl-1,3-oxazol-5-one/2-methyl-2-phenyl-1,3-oxathiolan-5-one, with aromatic aldehydes and urea/thiourea enantio- and diastereoselectively, yields 5-amino-/mercaptoperhydropyrimidines. This three-component domino cyclocondensation reaction is effected via ring transformation of an isolable intermediate in a one-pot procedure.     

Baylis-Hillman reaction in [bdmim][PF6] ionic liquid

A new use of ionic liquid [bdmim][PF₆] as solvent for the Baylis-Hillman reaction is presented. Unlike the commonly used [bmim][PF₆] that evidently reacts with electrophilic aldehydes under basic conditions, ionic liquid [bdmim][PF₆] is inert and the Baylis-Hillman reaction in [bdmim][PF₆] proceeds smoothly with better yield.     

Facile synthesis of thiourea derivatives in ionic liquid

The synthesis of cinnamoyl thiourea derivatives from cinnamoyl isothiocyanate (CIT) with substituted aniline (RC6H4NH2) was investigated in the mostly used ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate, [Bmim][BF4]. Significant enhance-ments in reactivity, yield and reaction rate were achieved. The products could be recovered by simple filtration. [Bmim][BF4] couldbe recycled simply by removing water under vacuum and reused at least 9 times without significant decrease in activity.     

An efficient synthesis of 3,4-dihydropyrimidin-2(1H)-ones catalyzed by molten [Et3NH][HSO4]

A simple ammonium salt of sulfuric acid in molten state was used as a cheap and mild acidic ionic liquid for efficient synthesis of 3,4-dihydropyrimidin-2(1H)-ones in good to excellent yields.     

The preparation of ionic liquid based iron phosphate/CNTs composite via microwave radiation for hydrogen evolution reaction and oxygen evolution reaction

Water electrolysis is a promising method for hydrogen production, so the preparation of low-cost and efficient electrocatalysts with a quick and simple procedure is crucial. Herein, iron phosphate (Fe₇(PO₄)₆) was prepared via microwave radiation using ionic liquid (IL) as iron and phosphorus dual-source. This method is simple and rapid, and the product can be directly used as electrocatalysts without further treatment. The experimental results show that the IL can influence the morphology and electrocatalytic performance. Moreover, the addition of carbon nanotubes (CNTs) is favorable for formation of iron phosphate nanoparticles to improve the catalytic activities. As hydrogen evolution reaction (HER) catalyst, this iron phosphate/CNTs exhibits an onset overpotential of 120 mV, Tafel slope of 32.9 mV dec^-1, and current densities of 10 mA cm⁻² at overpotential of 185 mV. Then, it obtains a good activity for oxygen evolution reaction (OER) with a low onset potential of 1.48 V, Tafel slope of 73.3 mV dec^-1, and it only needs an overpotential of 300 mV to drive the 10 mA cm⁻². This bifunctional catalyst also shows good durability for HER and OER. This microwave-assisted method provides an outstanding strategy to prepare iron phosphate in a simple and fast process with good catalytic performance for water splitting.     

Functional ionic liquid from biorenewable materials: synthesis and application as a catalyst in direct aldol reactions

A new room temperature ionic liquid (IL) (2-hydroxyethyl)-trimethyl-ammonium (S)-2-pyrrolidinecarboxylic acid salt ([Choline][Pro]) has been synthesized from biorenewable and nontoxic raw materials (choline chloride and l(−)-proline) in a simple and relative green route. The IL has been demonstrated to be the efficient catalyst of the direct aldol reactions between ketones and aromatic aldehydes in water at room temperature. The aldol products can be obtained with good yields and the IL in aqueous phase can be separated easily and reused.     

Development of a novel ionic support and its application in the ionic liquid phase assisted synthesis of a potent antithrombotic

The synthesis of ionic support 1 and its application in the preparation of a set of amides and sulfonamides is described. The potential of 1 is further exemplified by its use in a one-pot multistep ionic liquid phase assisted synthesis of tirofiban analogue 2.     

Efficient synthesis of chlorohydrins: ionic liquid promoted ring-opening reaction of epoxides and TMSCl

The environmentally benign, highly efficient synthesis of chlorohydrins by cleavage of epoxides using TMSCl in ionic liquid, bmimPF₆, has been studied.     

Cost-effective ionic liquid for environmentally friendly synthesis of 3,4-dihydropyrimidin-2(1H)-ones

Abstract

A simple, efficient and environmentally friendly process for synthesis of 3,4-dihydropyrimidinones using a one-pot three-component condensation of aromatic aldehydes, β-dicarbonyl compounds, and urea/thiourea is discussed. The cost-effective, new generation ionic liquid (IL), tri-(2-hydroxyethyl) ammonium acetate was used as both solvent and catalyst. The reactions were carried out using both conventional heating and microwave energy. Application of IL technology with microwave energy represents an attractive and rapid alternative to the conventional acid–base catalyzed thermal processes.     

A synthesis of diethyl alkylsulfanylmethylmalonates catalyzed by KOH in an ionic liquid

Abstract  1-Ethyl-3-methylimidazolium bromide was used as a green recyclable alternative to volatile organic solvents for KOH catalyzed three-component synthesis of diethyl alkylsulfanylmethylmalonates from aldehydes, diethyl malonate, and alkylthiols. Graphical Abstract  A synthesis of diethyl alkylsulfanylmethylmalonates catalyzed by KOH in an ionic liquid      

Selenonium ionic liquid as efficient catalyst for the Baylis-Hillman reaction

The new acidic ionic liquid phenyl butyl ethyl selenonium tetrafluoroborate, [pbeSe]BF₄, was successful used as a co-catalyst in the Baylis-Hillman reaction of aldehydes and electron-deficient alkenes. The Baylis-Hillman adducts were obtained in moderated to good yields and in relatively short reaction times under mild conditions.     

Synthesis of a novel poly(ethylene glycol) grafted triethylamine functionalized dicationic ionic liquid and its application in one-pot synthesis of 2-amino-2-chromene derivatives in water

A novel poly(ethylene glycol) grafted triethylamine functionalized dicationic ionic liquid has been prepared and characterized. It was successfully used as an efficient catalyst for the three-component synthesis of 2-amino-2-chromene derivatives in water. The simple workup, mild reaction conditions, wide substrate flexibility, excellent yields, and environmental friendliness are notable advantages of this protocol. In addition, the catalyst could be reused several times without appreciable reduction of catalytic activity.     

Ion insertion into ionic liquid supported toluene generated by electrochemical redox reaction

Ion transfer across the toluene|water, toluene–ionic liquid mixture|water and ionic liquid|water boundary generated by electrochemical redox reaction of tert-butylferrocene (tBuFc) was studied with the glassy carbon (GC) electrode partially covered by the organic liquid deposit and immersed in the aqueous electrolyte solution. The electrooxidation of the redox probe in toluene deposit is followed by ejection of newly formed cation into the aqueous solution. The same reaction in the toluene–ionic liquid deposit promotes anion insertion. This pathway is also found at the electrode modified with ionic liquid.     

Ni ion-containing immobilized ionic liquid on magnetic Fe3O4 nanoparticles: An effective catalyst for the Heck reaction

In this work, we synthesized Ni²⁺-containing 1-methyl-3-(3-trimethoxysilylpropyl) imidazolium chloride ionic liquid on magnetic Fe₃O₄ nanoparticles. The catalytic activity of these novel nanocomposites was finally evaluated for the Heck reaction at 100 °C, and can be reused after washing without loss in activity. The immobilized ionic liquid catalysts proved to be effective and easily separated from the reaction media by applying an external magnetic field. This procedure has many obvious advantages compared to those reported in the previous literature, including avoidance of the use of the expensive Pd catalysts, mild reaction conditions, high yields, and simplicity of the methodology.     

One-pot synthesis of quinoxaline-2-carboxylate derivatives using ionic liquid as reusable reaction media

The catalyst-free one-pot synthesis of quinoxaline-2-carboxylate is reported by the reaction of α-halo-β-ketoesters with 1,2-diamines using an ionic liquid as an environmentally benign solvent. The recovered ionic liquid was reused for four to five cycles. Moreover, the method is applicable for a variety of 1,2-diamines and α-halo-β-ketoesters.     

Biginelli reaction for synthesis of novel trifluoromethyl derivatives of bis(tetrahydropyrimidinone)benzenes

A facile one-pot three-component condensation of terephthalic aldehyde with urea and fluorinated 1,3-dicarbonyl derivatives is developed using catalytic quantities of chlorotrimethylsilane at ambient temperature. As a consequence, efficient synthesis of novel trifluoromethyl derivatives of bis(tetrahydropyrimidinone)benzenes is observed within short time periods. The procedure is shown to be equally efficient when urea is replaced with thiourea or guanidine.     

吗啡啉碱性离子液体催化合成油酸甲酯

采用两步法合成了由阳离子N-甲基-N-丁基吗啡啉和阴离子氢氧根搭配的[Nbmm]OH新型碱性离子液体。实验利用FT-IR、元素分析和TGA分别对该离子液体的化学结构和热稳定性进行了表征。结果表明,该离子液体的热稳定性超过200℃。对该离子液体的溶解性能进行了考察, 结果表明,该离子液体能与强极性溶剂互溶,而且其水溶液的碱性较强。为了考察该离子液体对酯化反应的催化活性,实验过程中以油酸和甲醇反应生成油酸甲酯的酯化反应为模型反应,评价该离子液体的催化活性。结果表明,当反应温度60℃、酸醇比为1:6、离子液体加入量为原料总质量的15%、反应10 h时,油酸转化率达93.9%,而且该离子液体易于从反应体系中分离,可以循环使用。