Ionic Liquid–Catalyzed Internal Redox Esterification Reaction

The internal redox esterification of α,β-unsaturated aldehydes and alcohols was carried out using different ionic liquids (ILs) as catalysts and reaction solvents. The basic ionic liquid, 1-butyl-3-methylimidazolium acetate ([bmim]OAc), exhibited the best activity for this reaction. The influences of the amount of ionic liquid catalyst and reaction time on yield of saturated ester have been investigated. The results showed that ionic liquid anions have a crucial effect on the redox esterification of α,β-unsaturated aldehydes and alcohols. The nucleophilic carbenes generated in situ from the ionic liquid cation were believed to be actual active species for this reactions.     

Ammonium Chloride–Catalyzed One-Pot Synthesis of 4(3H)-Quinazolinones Under Solvent-Free Conditions

Ammonium chloride, which is a very inexpensive and readily available reagent, can efficiently catalyze three-component, one-pot condensation reactions of 2-amino-benzoic acid esters, ortho esters, and aromatic amines to afford the corresponding 4(3H)-quinazolinones in good to excellent yields under solvent-free conditions.     

Clean Procedure for the Synthesis of α-Aminophosphonates Catalyzed by Biodegradable Ionic Liquid

Abstract

A biodegradable SO₃H-functionalized ionic liquid (IL) was prepared and used as the catalyst for a one-pot, three-component condensation synthesis of α-aminophosphonates from aldehydes, amines, and triethylphosphite/diethylphosphite at room temperature under solvent-free conditions or in aqueous media. The products could be simply separated from the reaction mixture and the catalyst could be recycled and reused for several times without noticeably reducing catalytic activity.     

Synthesis of Tetrahydrofuran and Tetrahydropyran Derivatives Catalyzed by Tungstophosphoric Acid in Ionic Liquid

Synthesis of tetrahydrofuran and tetrahydropyran derivatives catalyzed by tungstophosphoric acid （H3PW12040） were conveniently performed with high yield from the corresponding unsaturated alcohols in ionic liquid. Sufuric acid （H2SO4）, trifluoromathanesulfonic acid （TfOH） and p-toluenesulfonic acid （TsOH） were also explored for preparing these products in ionic liquid. The catalysts and ionic liquid can be easily recovered and reused.     

Ionic Liquid–Liquid Extraction and Supported Liquid Membrane Analysis of Lipophilic Wood Extractives from Dissolving-Grade Pulp

In this study, the extraction of lipophilic wood extractives from dissolving pulp samples using ionic liquid–liquid extraction and a two phase hollow fibre supported liquid membrane was investigated. Ionic liquids are capable of dissolving a range of organic and polymeric compounds and are biodegradable, with a negligible vapour pressure. Pulp samples were dissolved in a suitable amount of molten 1-butyl-3-methylimidazolium chloride to give 5 % cellulose solution. Pure cellulose was regenerated by adding water and filtered off. The ionic liquid-aqueous filtrate was first extracted for lipophilic extractives using liquid–liquid extraction. Then, a two phase hollow fibre supported liquid membrane extraction of lipophilic extractives was performed to extract the derivatized compounds prior to analysis by gas chromatography mass spectrometry. The operational parameters of this sample preparation approach were optimised using sterols and fatty acid methyl esters. The variation of enrichment factors and extraction efficiency with respect to liquid membrane, extraction time, stirring speed and sample pH were observed and used to get the optimal parameters. The approach was used in the analysis of oxygen bleached dissolving pulp samples in which main compounds identified were fatty acids, sterols, fatty alcohols, steroid hydrocarbons and ketones. These compounds were similar to those obtained using molecular solvent extraction method, which indicated the absence of chemical reaction between extractives and ionic liquid used.

     

Brønsted Acidic Ionic Liquid–Catalyzed One-Pot Synthesis of 3,4-Dihydropyrimidin-2(1H)-ones and Thiones Under Solvent-Free Conditions

An efficient and convenient procedure for the synthesis of 3,4-dihydropyrimidin-2(1H)-ones and thiones by condensation of ethylacetoacetate, aldehydes, and urea or thiourea in the presence of methylimidazolium hydrogensulfate is described. Aromatic and aliphatic aldehydes reacted easily to afford the corresponding 3,4-dihydropyrimidin-2(1H)-ones and thiones under solvent-free conditions. The use of nontoxic and inexpensive materials, straightforward and clean workup, short reaction times, and good yields are the advantages of this method.

Facile Synthesis of Ureas in Ionic Liquid

The urea functional group is of importance in a wide range of biological compounds such as enzyme inhibitors1 and pseudopeptides2. Substituted ureas are widely applied in fine chemical industry, especially pesticides3 and pharmaceuticals4. Many investigations have been made to search for an efficient and practical method to synthesize ureas. The typical procedure for the synthesis of ureas is treating isocyanates with primary or secondary amines in organic solvents5. In the presence of trans…     

Highly Efficient One-Pot,Three-Component Synthesis of β-Aminoketones Catalyzed by Fe(O2CCF3)3

A highly efficient one-pot, three-component synthesis of β-aminoketones was demonstrated using the cost-effective, noncorrosive, and easily available Fe(O₂CCF₃)₃ as a catalyst for the first time. The method can be employed to synthesize a wide range of target compounds and to introduce different functional groups into the β-aminoketone skeleton. Additionally, the method consistently has the advantages of good yields, short reaction time, and simply experimental workup procedure, which makes it a useful process for the synthesis of functionalized β-aminoketones.     

Phosphonium Ionic Liquid–Catalyzed Michael Addition of Mercaptans to α,β-Unsaturated Ketones

A clean and efficient Michael addition reaction on chalcones using phosphonium ionic liquid catalyst (PhosIL-Cl) is described. The method provides several advantages, such as simple workup, environmental friendliness, mild conditions, and excellent yields. In addition, the ionic liquid was chosen as a green solvent, recovered, and reused several times in subsequent reactions.     

Efficient and Eco-friendly Process for the Synthesis of Bi（indolyl）-methanes Catalyzed by Sodium Hydrogensulfate Monohydrate in Ionic Liquid n-Butylpyridinium Tetrafluoroborate

Indole fragment is featured widely in a wide variety of pharmacologically and biologically active compounds1. A large number of bi(indolyl)methanes have been reported to be isolated from terrestrial and marine natural sources, viz. parasitic bacteria, tun…     

Phase Transfer–Catalyzed,One-Pot Synthesis of Some Novel N-Pyrimidinyl-N′-nicotinyl Thiourea Derivatives

Abstract

A new series of acyl thiourea derivatives were synthesized in one-pot using PEG-600 as the phase transfer catalyst (PTC). The structures of title compounds were characterized by ¹H NMR, IR, MS, and elemental analysis. In addition, the fungicidal activity of the acyl thiourea derivatives were tested, which showed that most of them exhibit moderate activity.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.

GRAPHICAL ABSTRACT      

The Synthesis of 2, 4, 6-Triisopropyl-1, 3, 5-trioxane Catalyzed by Ionic Liquids

The synthesis of 2, 4, 6-triisopropyl- 1, 3, 5-trioxane with high yield and desirable selectivity from solvent-free cyclotrimerization of isobutyraldehyde catalyzed by ionic liquids was reported in this work.     

One-Pot Synthesis of β-Phosphonomalonates Catalyzed by Molecular Iodine

A one-pot procedure has been developed for the synthesis of β-phosphonomalonates via P-C bond formation through tandem Knoevenagel–phospha–Michael reaction catalyzed by iodine as a new, inexpensive, nonmetallic, and commercially available catalyst.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.]     

Electrochemical Synthesis of Polythiophene in an Ionic Liquid

Polythiophene(PTh) was prepared by the direct electrochemical synthesis in an ionic liquid ([BMIM]PF6) containing 0.1mol/L thiophene by cyclic voltammetry,constant potential and constant current techniques. It is found that smooth and blue-green PTh films can be obtained at a potential of ca. 1.75V(vs. Ag/AgCl) or a current of ca. 1.5mA cm^-2 in the ionic liquid.     

Acidic Ionic Liquid–Catalyzed Highly Efficient Reaction of Indoles to α,β‐Unsaturated Ketones

A novel method for the Michael reaction of indoles to α,β‐unsaturated ketones catalyzed by acidic ionic liquid is reported. We obtained the corresponding products in excellent yields in the presence of [hmim]HSO₄. Development of this method has resulted in a new protocol for the synthesis of β‐indolylketones.     

Ionic Liquid–Catalyzed One-Pot Synthesis of 1H-Pyrano[2,3-d]pyrimidin-2(8aH)-one Derivatives via Three-Component Reaction under Solvent-Free Conditions

A series of 1H-pyrano[2,3-d]pyrimidin-2(8aH)-one derivatives were synthesized via one-pot, three-component reaction of aromatic aldehydes, urea or thiourea, and 3,4-dihydro-2H-pyran using the green and inexpensive Brønsted acidic ionic liquid 1-methyl-2-pyrrolidinone hydrosulfate ([Hnmp]HSO₄) as catalyst under solvent-free conditions. The method has several advantages such as mild conditions, shorter reaction time, good yields, and environmentally benign procedure. Moreover, the catalyst could be recovered conveniently and reused at least four times without evident loss of activity.     

Sulfamic Acid–Catalyzed,Three-Component,One-Pot Synthesis of [1,2,4]Triazolo/Benzimidazolo Quinazolinone Derivatives

An efficient and convenient approach is reported for three-component, one-pot synthesis of the [1,2,4]triazolo/benzimidazolo quinazolinones by condensation of 2-amino benzimidazole or 3-amino-1,2,4-triazole as amine sources with dimedone and different aldehydes in the presence of sulfamic acid as a reusable, green catalyst in acetonitrile and under heating conditions.     

Ionic Liquid–Mediated One-Pot Synthesis of 5-(Trifluoromethyl)-4,7-dihydrotetrazolo[1,5-a]pyrimidine Derivatives

A facile one-pot synthesis of 5-(trifluoromethyl)-4,7-dihydrotetrazolo[1,5-a]pyrimidine derivatives is described via a three-component reaction of aldehydes with 5-aminotetrazole and ethyl 4,4,4-trifluoro-3-oxobutanoate or 4,4,4-trifluoro-1-phenylbutane-1,3-dione in ionic liquid. This method has the advantages of short synthetic route, operational simplicities, good yields, ecofriendliness, and recyclability of the solvent.     

Synthesis of N-（α-Alkoxyalkyl）benzotriazoles Catalyzed by Acidic Ionic Liquid at Room Temperature

N-（α-Alkoxyalkyl）benzotriazoles were synthesized via the condensation of benzotriazole with various aldehydes and alcohols catalyzed by acidic ionic liquid [hmim]HSO4 at room temperature. The yield was up to 99%. This novel method was effective when triethoxymethane was utilized instead of alcohols. Moreover, acidic ionic liquid could be reused easily with no significant degradation of its catalytic activity.