Catalyst For Biginelli Reaction Research Articles

Effect of the Exchanged Cation in an Algerian Montmorillonite Used as a Heterogeneous Catalyst for Biginelli Reaction

In this work, an Algerian montmorillonite (Mt) is exchanged by different cations from the transition metals family, namely: Cu2+, Ni2+, Cr3+, Co2+, Fe2+ and Fe3+, it is used as a heterogeneous catalyst for Biginelli reaction. The exchanged cations are known for their catalytic properties in homogeneous catalysis. The main purpose is to study the effect of the exchanged cations on the yield and the kinetics of the reaction. The characterization of montmorillonite was carried out by XRD, which allows us to follow the evolution of the basal spacing d001 as a function of the exchanged cation and to show that the exchange operation has not altered the montmorillonite structure. The cation exchange capacity (CEC) is determined by the titration of the exchanged cation by atomic absorption. The product of the reaction is characterized by NMR, IR and by the determination of the melting point. In addition, the importance of the introduction order of the reagents into the reaction medium has been demonstrated on the yield and the kinetics. Finally, the obtained results show that the exchanged montmorillonite is competitive with other costly heterogeneous and homogeneous catalysts.

Green Synthesis of Substituted Dihydropyrimidin-2(1H)-one by Using Zinc Chloride /Acetic Acid Catalytic System

Background: Biginelli reaction is the most well-known and widely studied, multicomponent reaction used for the direct synthesis of many biologically active 3,4-dihydropyrimidin- 2(1H)-ones and their derivatives by reacting a β-keto ester/1,3-dicarbonyl compound, an aldehyde, and urea. It is catalyzed by different Bronsted and Lewis acids. Methods: The catalytic effect of different metal chlorides, such as sodium, potassium, magnesium, stannous, ferric, manganese, cupric, nickel, cobalt, and zinc, in absence and presence of acetic acid were studied. Results: The zinc, ferric, cupric, and cobalt chlorides were found to be more effective catalysts for Biginelli reaction at room temperature. The yield of the reaction increased with temperature for all catalytic systems. Acetophenone, cyclohexanone, acetyl acetone, and different β-ketoesters formed tetrahedropyrimidine in moderate to good yield, by using zinc chloride catalyst at room temperature in acetic acid. The efficiency of the catalyst was studied by treating different substituted aldehydes with 1,3-dicarbonyl compounds and urea at room temperature. Conclusion: The zinc chloride in acetic acid found to be an effective greener catalyst system for Biginelli reaction.

Shape-controlled synthesis of sodium zincate mesoporous structures based on sulfonated melamine formaldehyde and their application as catalysts for Biginelli reaction

In the current research, two mesoporous structures of sodium zincate [Na2Zn(OH)4], spheres and aggregated particles, has been synthesized from sulfonation of melamine-formaldehyde (MF) and then bounding [Na2Zn(OH)4] particles onto the surface of sulfonated melamine–formaldehyde (SMF). Furthermore, in the present synthetic methodology the zinc oxide (ZnO) thin films on sulfonated melamine–formaldehyde was formed via the chemical deposition, and thermal treatment techniques of the sodium zincate. Several spectroscopic and analytical methods proved the structural and morphological properties of sodium zincate mesoporous structures based on sulfonated melamine formaldehyde [SMF/Na2Zn(OH)4]. The experimental studies showed that these catalytic systems showed high activity in the Biginelli reaction for the synthesis of 3,4-dihydropyrimidin-2(1H)-one derivatives and will find recoverable potential application. The obtained results indicated that the synthesized mesoporous structures had a thermal stability near 300 °C, particle-size distribution around of 10–120 nm for spheres and the surface area of 6 and 2 m2/g for spheres and aggregated particles, respectively.

Niobium chloride in 1−n−butyl−3−methylimidazolium chloride ionic liquid as a catalyst for biginelli reaction

In this study, NbCl5 in a liquid ionic medium was evaluated as a catalyst for Biginelli reaction. Firstly, the ionic species found in mixtures of NbCl5 and 1−butyl−3−methylimidazolium chloride (BMImCl) at various molar ratios (x) were determined. Samples with x ranging from 0.2 up to 0.4 were constituted of BMIm+, Cl− and [NbCl6]− ions in different proportions. When x was 0.5, BMIm+ and [NbCl6]− were the only species. When the molar ratio was 0.6 a mixture of BMImNbCl6 and Nb2Cl10 was observed. The identification of the ionic species provides useful information about the chemical nature of the niobium catalyst in the Biginelli reaction and other chemical or electrochemical transformations. The Biginelli reaction carried out using ethyl acetoacetate, benzaldehyde and urea in the presence of NbCl5 and xNbCl5_BMImCl mixtures with x varying from 2 to 5 yielded almost 90% of 3,4-dihydropyrimidinone, which means the acid C (2) hydrogen in the BMIm+ with [NbCl6]- as the counterion acted as Brønsted acid capable of bonding to the CO of benzaldehyde and ethyl acetoacetate, following the iminium mechanism.

Long-chain Brønsted acidic ionic liquids catalyzed one-pot three-component Biginelli reaction

Purpose From the atom economy and environmentally friendly point of views, the development of clean and green approaches using ionic liquids (ILs) as recyclable catalysts has attracted increasing attention. The purpose of this study is to investigate the effect of task-specific ILs content on the one-pot three-component Biginelli reaction. Design/methodology/approach A series of halogen-free quaternary ammonium ILs functionalized with –SO3H group were prepared and characterized by 1H nuclear magnetic resonance (NMR), 13C NMR and electrospray ionization mass spectrometry. The ILs were used as catalysts for Biginelli reaction among aromatic aldehydes, urea or thiourea and β-dicarbonyl compounds. Anions and cations of ILs were varied to observe their effects on and contributions to the catalysts. The influencing factors, such as the amount of catalyst, solvent, reaction time and reaction temperature, were investigated. Findings The effect and contribution of cations of ILs were observed. Results showed that 3-(N, N-dimethylhexadecylammonium) propanesulfonic acid toluene sulfate ([DHPA][Tos]) showed comparable catalytic activity. Good adaptability to the reaction substrate and maximum product yield was observed when [DHPA][Tos] was used as catalyst. It was found that Biginelli reaction catalyzed by 10 mol% [DHPA][Tos] for 3 h under solvent-free conditions at 80 °C gave the best yield of 94%. Post-processing steps were simple, and the catalyst could be reused easily. Originality/value This paper demonstrates that ILs containing a long carbon chain and a bulky Tos anion efficiently promoted the reaction, in which the long carbon chains facilitate mass transfer in the reaction system.

Brønsted Acidic 1-Ethyl-1,2,4-Trizolium Phenylsulfonate as Catalyst for Biginelli Reaction

Brønsted Acidic 1-Ethyl-1,2,4-Trizolium Phenylsulfonate as Catalyst for Biginelli Reaction

Starch Sulfuric Acid: an Alternative, Eco-Friendly Catalyst for Biginelli Reaction

Starch Sulfuric Acid: an Alternative, Eco-Friendly Catalyst for Biginelli Reaction

An Environmentally Benign One-Pot Synthesis of 3,4-Dihydropyrimidin-2(1H)-ones and -thiones Using Tetrabutylammonium Hexatungstate [TBA]2[W6O19] as a Recyclable Catalyst

Tetrabutylammonium hexatungstate [TBA]2[W6O19], an isopolytungstate, was found to be a highly efficient and recyclable heterogeneous catalyst for Biginelli reaction of ethyl acetoacetate, an aryl aldehyde, and urea or thiourea under solvent-free conditions, giving rise to 3,4-dihydropyrimidin-2(1H)-ones and -thiones. Good to high yields, short reaction times, easy workup, and absence of any volatile and hazardous organic solvents are just a few of the advantages of this procedure. Furthermore, the catalyst can be recycled after a simple workup, and can be used at least three times without substantial reduction in its catalytic activity.

Recyclable Amberlyst-70 as a Catalyst for Biginelli Reaction: An Efficient One-Pot Green Protocol for the Synthesis of 3,4-Dihydropyrimidin-2(1H)-ones

An environmentally benign aqueous protocol for the synthesis of 3,4-dihydropyrimidin-2(1H)-ones using Amberlyst-70 as a recyclable catalyst has been developed. The use of resinous, nontoxic, thermally stable and inexpensive Amberlyst-70, as a recyclable heterogeneous catalyst, makes the process simple with negligible chemical waste. Thus renders this method an environmentally acceptable synthetic tool for Biginelli reaction.

POTASSIUM MONOPEROXYSULFATE AN EFFICIENT CATALYST FOR BIGINELLI REACTION UNDER AQUEOUS CONDITIONS

Article POTASSIUM MONOPEROXYSULFATE AN EFFICIENT CATALYST FOR BIGINELLI REACTION UNDER AQUEOUS CONDITIONS was published on February 1, 2007 in the journal Heterocyclic Communications (volume 13, issue 1).