Brønsted Acid Ionic Liquid [(CH2)4SO3HMIM][HSO4] as Novel Catalyst for One-Pot Synthesis of Hantzsch Polyhydroquinoline Derivatives

1-(4-Sulfonic acid)butyl-3-methylimidazolium hydrogen sulfate ([(CH₂)₄SO₃HMIM][HSO₄]) efficiently catalyzed a four-component Hantzsch reaction of aldehyde, ethylacetoacetate, dimedone, and ammonium acetate to afford the corresponding polyhydroquinoline derivatives.     

Application of [Fe3O4@SiO2@(CH2)3Py]HSO4− as heterogeneous and recyclable nanocatalyst for synthesis of polyhydroquinoline derivatives

Four‐component condensation reaction of aromatic aldehydes, dimedone, ethyl acetoacetate and ammonium acetate in the presence of a catalytic amount of ionic liquid on silica‐coated Fe₃O₄ nanoparticles as a heterogeneous, recyclable and very efficient catalyst provided the corresponding polyhydroquinoline derivatives in good to excellent yields in ethanol under reflux condition. The [Fe₃O₄@SiO₂@(CH₂)₃Py]HSO₄^? catalyst was characterized using various techniques such as scanning electron microscopy, powder X‐ray diffraction, thermogravimetric analysis, vibrating sample magnetometry and Fourier transform infrared spectroscopy. Furthermore, the recovery and reuse of the catalyst were demonstrated seven times without detectable loss in activity.     

Solvent‐free synthesis of new 2,4,6‐triarylpyridines catalyzed by a Brønsted acidic ionic liquid as a green and reusable catalyst

Some new 4‐(aryl)‐2,6‐di‐2‐naphthylpyridines and 4‐(aryl)‐2,6‐di‐2‐thienylpyridines have been prepared through three‐component condensation of 2‐acetylnaphthalene or 2‐acetylthiophene, aromatic aldehydes, and ammonium acetate in presence of 1‐(4‐sulfonylbutyl) pyridinium hydrogensulfate [(CH₂)₄SO₃HPy][HSO₄], a Brønsted acidic ionic liquid as a green and reusable catalyst in solvent‐free conditions. Also some new 4,4'‐(1,4‐phenylene)‐bis‐(2,6‐di‐aryl pyridine) was prepared. J. Heterocyclic Chem., (2011).     

Brønsted acidic ionic liquids catalyze the preparation of 2,3-dihydroquinazolin-4(1H)-one derivatives

A simple and facile method for the green synthesis of 2,3-dihydroquinazolin-4(1H)-one derivatives by direct three-component cyclo-condensation of isatoic anhydride, ammonium acetate (or primary amines), and arylaldehydes using different Brønsted acidic ionic liquids, for example 2-pyrrolidonium hydrogensulfate ([hnmp][HSO₄]), N-methyl-2-pyrrolidonium hydrogensulfate ([NMP][HSO₄]), and N-methyl-2-pyrrolidonium dihydrogenphosphate ([NMP][H₂PO₄]), as reusable catalysts under solvent-free conditions is described. In addition, reaction of anthranilamide and arylaldehydes for synthesis of 2,3-dihydroquinazolin-4(1H)-one derivatives was investigated.     

pH-responsive deoxyribonucleic acid capture/release by polydopamine functionalized magnetic nanoparticles

Polydopamine functionalized magnetic nanoparticles (PDA@Fe₃O₄) were prepared and characterized by transmission electron microscopy, scanning electron microscopy, zeta potential and vibrating sample magnetometry. They were found to enable highly efficient capture of genomic deoxyribonucleic acid (DNA). The adsorption capacity of PDA@Fe₃O₄ for genomic DNA can reach 161 mg g⁻¹. The extraction protocol used aqueous solutions for DNA binding to and releasing from the surface of the magnetic particles based on the pH inducing the charge switch of amino and phenolic hydroxyl groups on PDA@Fe₃O₄. The extracted DNA with high quality (A₂₆₀/A₂₈₀ = 1.80) can be directly used as templates for polymerase chain reaction (PCR) followed by capillary electrophoresis (CE) analysis. None of the toxic chemical reagents and PCR inhibitors was used throughout the whole procedure. PDA@Fe₃O₄ based magnetic solid phase extraction (MSPE) method was superior to those using commercial kit and traditional phenol–chloroform extraction methods in yield of DNA. The developed PDA@Fe₃O₄ based MSPE-PCR-CE method was applied for simultaneous and fast detection of Listeria monocytogenes and Escherichia coli O157:H7 in milk.     

On Water: Brφnsted Acidic Ionic Liquid[(CH2)4SO3HMIM][HSO4]Catalysed Synthesis of Oxindoles Derivatives

Some oxindoles derivatives are synthesized from the condensation of indoles with isatins in the presence of green and recycable catalyst [(CH₂)₄SO₃HMIM][HSO₄] in water at room temperature.     

Green,One-Pot,Solvent-Free Synthesis of 1,2,4,5-Tetrasubstituted Imidazoles Using a Brønsted Acidic Ionic Liquid as Novel and Reusable Catalyst

3-Methyl-1-(4-sulfonic acid)butylimidazolium hydrogen sulfate [(CH₂)₄SO₃HMIM][HSO₄], a Brønsted acidic ionic liquid, has been used as an efficient, green, and reusable catalyst for the synthesis of 1,2,4,5-tetrasubstituted imidazoles using benzil, an aromatic aldehyde, and a primary amine in the presence of ammonium acetate under solvent-free conditions. The catalyst could be recycled and reused several times without noticeably decreasing the catalytic activity.     

Comparison of acidities in molten hydrogenosulphates and their eutectics

Acidity in pure hydrogenosulphates NaHSO₄, KHSO₄, NH₄HSO₄ and in their eutectics (Na-K)HSO₄, (K-NH₄)HSO₄ and (NH₄-Na)HSO₄, was studied, at t=200°C and P(H₂O) =0.03 atm, by using an indicator glass-electrode. The values of the constants of autoprotolysis and of the solubilities of alkaline and ammonium sulphates have been determined for each of the molten salts considered. The acidity ranges available in these solvents were then compared by means of a single acidity scale referring to pure sulphuric acid. This comparison was made possible by mearusing, with a transference method, the vapour pressures of the sulphuric acid above its solutions in hydrogenosulphates and their eutectics. So, it demonstrated that the more acidic media are obtained in the eutectic (Na-K)HSO₄, and the more basic ones in NH₄HSO₄. Moreover, various thermodynamic functions, and especially, the standard entropies of the pure hydrogenosulphates, have been determined     

Hydrolysis of magnesium hydride in the presence of ammonium salts

The influence of the nature of ammonium salts (NH₄Cl, (NH₄)₂SO₄, (NH₄)HSO₄, [(CH₃)NH₃]Cl) and their concentration in aqueous solutions on the hydrolysis of magnesium hydride has been studied. The highest degree and fastest rate of hydrolysis are observed at an ammonium salt concentration of ～7.5%. The most efficient activator among the ammonium salts under consideration is (NH₄)HSO₄.     

Highly efficient, one-pot, solvent-free synthesis of 2,4,6-triarylpyridines using a Br?nsted-acidic ionic liquid as reusable catalyst

Abstract  

A simple, efficient, and green method for synthesis of 2,4,6-triarylpyridines by one-pot three-component reaction of acetophenones, aryl aldehydes, and ammonium acetate using 3-methyl-1-(4-sulfonylbutyl)imidazolium hydrogen sulfate [HO₃S(CH₂)₄MIM][HSO₄], a Br?nsted-acidic ionic liquid, as an effective and reusable catalyst under solvent-free conditions is described. This method has several advantages, for example simple procedure with an easy work-up, shorter reaction times, and high yields.     

S‐Benzylisothiourea complex of palladium on magnetic nanoparticles: A highly efficient and reusable nanocatalyst for synthesis of polyhydroquinolines and Suzuki reaction

S ‐Benzylisothiourea complex of palladium supported on modified Fe₃O₄ magnetic nanoparticles (Pd‐SBTU@Fe₃O₄) is reported for carbon–carbon coupling through the Suzuki coupling reaction. Also, the synthesis of polyhydroquinoline derivatives is reported in the presence of Pd‐SBTU@Fe₃O₄ as nanocatalyst. The prepared nanoparticles were characterized using Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, vibrating sample magnetometry and inductively coupled plasma atomic emission spectroscopy. The nanocatalyst was easily recovered using an external magnet and reused several times without significant loss of its catalytic efficiency. The heterogeneity of Pd‐SBTU@Fe₃O₄ was studied using hot filtration.     

Al(HSO4)3 and Al2O3-SO3H as Efficient Catalysts for Modified Preparation of 3,4-Dihydropyrimidin-2 (1H)-ones/thiones

An environmentally friendly procedure for the preparation of dihydropyrimidinone derivatives or their sulfur analogues under thermal solvent-free conditions in the presence of aluminium hydrogen sulfate [Al(HSO₄)₃] and alumina sulfuric acid (Al₂O₃-SO₃H) as heterogeneous catalysts was developed.     

Direct sulfonylation of Baylis-Hillman alcohols and diarylmethanols with TosMIC in ionic liquid-[Hmim]HSO4: an unexpected reaction

A Brønsted acidic ionic liquid-[Hmim]HSO₄ promoted unexpected reaction of Baylis-Hillman alcohols and diarylmethanols with p-toluenesulfonylmethyl isocyanide (TosMIC) affording the corresponding sulfone derivatives instead of N-tosylmethyl amides is reported. After isolation of the product, the ionic liquid [Hmim]HSO₄ was easily recycled for further use.     

Efficient syntheses of C20-carotene and crocetin (descrocetin) esters promoted by an acidic ionic liquid

Efficient syntheses of C₂₀-carotene and crocetin or descrocetin esters from fumaraldehyde bis-dimethylacetal are described. The key steps of these syntheses are the reactions of fumaraldehyde and (2E,4E,6E)-octa-2,4,6-trienedial bis-dimethylacetals with alkyl vinyl or alkyl propenyl ethers promoted by the acidic ionic liquid, [emim][HSO₄].     

Synthesis,film-forming properties,and thermal and light sensitivity of <Emphasis Type="Italic">N,N′</Emphasis>-bis[4-hydroxy(alkoxy,acyloxy)-3-alkoxyphenylmethylidene]benzene-1,4-diamines

Previously unknown E,E-isomeric Schiff bases were synthesized by reaction of p-phenylenediamine with 4-hydroxy-3-methoxybenzaldehyde, 3-ethoxy-4-hydroxybenzaldehyde, and their O-alkyl and O-acyl derivatives in anhydrous methanol. Film-forming properties and thermal and light sensitivity of the products were studied.     

Polyvinyl amine as a modified and grafted shell for Fe3O4 nanoparticles: As a strong solid base catalyst for the synthesis of various dihydropyrano[2,3-c]pyrazole derivatives and the Knoevenagel condensation

In this work, we reported one-step deposition of polyacrylamide on nano-magnetite surface via a simple and in situ polymerization of acryl amide to form n-Fe₃O₄/PAM nanocomposite. The amide (–CONH₂) groups could be converted easily to amine (–NH₂) groups through Hofmann degradation to introduce n-Fe₃O₄/PVAm as a highly efficient heterogeneous base catalyst. The obtained organic-inorganic nanocomposite exhibited high catalytic activity for the solvent-free syntheses of various dihydropyrano[2,3-c]pyrazole derivatives and the Knoevenagel condensation in high to excellent yields and in the following, a plausible mechanism for the synthesis of them has been proposed. Because of the polymer layer coated Fe₃O₄ nanoparticles, the catalyst has many catalytic units, and acceptable thermal stability and recyclability. Titration, FT-IR, SEM, TGA, VSM, and XRD analysis were used for characterization of the catalyst. Also, the nanocomposite can be easily recovered by a magnetic field and reused up to 9 times without distinct deterioration in catalytic activity.     

SO3H-Functionalized Ionic Liquids: Green, Efficient and Reusable Catalysts for the Facile Dehydration of Aldoximes into Nitriles

Easily synthesized aldoximes have been converted to the corresponding nitriles under very mild conditions by a simple reaction using two halogen‐free SO₃H‐functionalized ionic liquids, 3‐methyl‐1‐(4‐sulfonic acid)butylimi‐ dazolium hydrogen sulfate [MIM(CH₂)₄SO₃H][HSO₄] and 1‐(4‐sulfonic acid)butylpyridinium hydrogen sulfate [PY(CH₂)₄SO₃H][HSO₄], as catalyst and reaction medium without any additional organic solvent. The method was equally effective for aromatic aldoximes bearing electron‐donating and electron‐withdrawing substituents. Taking into account environmental and economical consideration, the protocol presented here has the merits of environmentally friendly, simple operation, easy work‐up and very good yields. The catalysts could be recycled and reused for several times without noticeably decreasing in their catalytic activities.     

Crystal structures of Ti(NH<Subscript>4</Subscript>)<Subscript>2</Subscript>P<Subscript>4</Subscript>O<Subscript>13</Subscript> and Sn(NH<Subscript>4</Subscript>)<Subscript>2</Subscript>P<Subscript>4</Subscript>O<Subscript>13</Subscript>

The characteristics of crystal structures of the titanium(IV) diammonium (Ti(NH₄)₂P₄O₁₃) and tin(IV) diammonium (Sn(NH₄)₂P₄O₁₃) tetraphosphates, which are isostructural with similar silicon(IV) and germanium(IV) salts, have been obtained by the Rietveld method using X-ray powder diffraction data. The compounds crystallize in the triclinic system, space group P \(\overline 1 \), Z = 2, a = 15.0291(7) Å, b = 7.9236(4) Å, c = 5.0754(3) Å, α = 99.168(3)°, β = 97.059(3)°, γ = 83.459(3)° for Ti(NH₄)₂P₄O₁₃ and a = 15.1454(7) Å, b = 8.0103(5) Å, c = 5.1053(3) Å, α = 99.898(6)°, β = 96.806(3)°, γ = 83.881(4)° for Sn(NH₄)₂P₄O₁₃. The structure is refined in the isotropic approximation using the pseudo-Voigt function: R _p = 0.077, R _Bragg = 0.045, R _F = 0.057 for Ti(NH₄)₂P₄O₁₃; R _p = 0.082, R _Bragg = 0.044, R _F = 0.046 for Sn(NH₄)₂P₄O₁₃. The hydrogen atoms of the ammonium cations are placed in the calculated positions. A comparative analysis of the structures of the compounds of the M^IV(NH₄)₂P₄O₁₃ (M^IV = Si, Ge, Ti, Sn) series has been carried out.