scholarly journals The ultrasound accelerated solvent-free synthesis of ethyl 7-methyl-5-phenyl-5H-thiazolo[3,2-a]pyrimidine-6-carboxylate through Biginelli reaction catalyzed by Amberlyst-15

2020 ◽  
Vol 4 (3) ◽  
pp. First
Author(s):  
Công-Thắng Dương ◽  
Xuan Thi Thi Luu
Keyword(s):  
Ethyl Acetoacetate ◽  
Biginelli Reaction ◽  
Maximum Yield ◽  
Ultrasound Irradiation ◽  
Solvent Free ◽  
Molecular Structures ◽  
Molar Ratio ◽  
Solid Catalyst ◽  
Reusable Catalyst ◽  
Amberlyst 15

Multi-component reactions (MCRs) played an important role to produce complex molecular structures in a one-step process. Among all MCRs reported, Biginelli reaction was one of the most well-known and used in organic synthesis to constitute pyrimidine scaffolds. Therefore, a solvent-free Biginelli reaction of 2-aminothiazole, benzaldehyde and ethyl acetoacetate catalyzed by Amberlyst-15 (A-15) had attracted us to pay attention and to do research in order to highly obtain a desired product, a frame of thiazolo[3,2-a]pyrimidine being present in many active biological compounds. Amberlyst-15, polystyrene resin regarded as a green acidic solid, available commercial, inexpensive and reusable catalyst had been firstly and successfully developed for solvent-free Biginelli reaction under ultrasound irradiation to form thiazolo[3,2-a]pyrimidine. Most factors which had influenced on the reaction conversion and yield such as the molar ratios between 2-aminothiazole, benzaldehyde and ethyl acetoacetate, the amounts of catalyst A-15, and reaction time had been investigated. Consequently, the yield of ethyl 7-methyl-5-phenyl-5H-thiazolo[3,2-a]pyrimidine-6-carboxylate had been also found to depend on the amount of the acidic solid catalyst and little excess amounts of the two reactants, e.g. 2-aminothiazole and ethyl acetoacetate. The maximum yield has been obtained 76% after six-hour ultrasound irradiation at 80oC with the molar ratio of 2-aminothiazole : benzaldehyde : ethyl acetoacetate (1.4:1.0:1.4) and 50 mg of catalyst A-15. The results showed that Amberlyst-15 had high capability of recovery and recycling owing to the inconsiderably changes of product yields after two recycle runs.

Synthesis of Dihydropyrimidinones (DHPMs) and Hexahydro Xanthene Catalyzed by 1,4-Diazabicyclo [2.2.2] Octane Triflate Under Solvent-Free Condition

2019 ◽  
Vol 16 (5) ◽  
pp. 776-786 ◽  
Author(s):  
Deepa ◽  
Geeta D. Yadav ◽  
Mohd J. Aalam ◽  
Pooja Chaudhary ◽  
Surendra Singh
Keyword(s):  
Ethyl Acetoacetate ◽  
Biginelli Reaction ◽  
Solvent Free ◽  
Efficient Catalyst ◽  
Solvent Free Condition ◽  
Solvent Free Conditions ◽  
Xanthene Derivatives ◽  
Different Temperatures ◽  
Flash Column Chromatography ◽  
Biginelli Condensation

Objective:DABCO salts were evaluated as catalysts for the Biginelli reaction between 4- methoxybenzaldehyde, urea and ethyl acetoacetate under solvent-free conditions. 1,4-Diazabicyclo [2.2.2] octane triflate was found to be a simple, inexpensive, highly efficient catalyst for Biginelli reaction for a variety aromatic aldehyde with urea and ethyl acetoacetate at 80°C afforded corresponding 3,4-dihydropyrimidinones in 50-99% yields after 30-120 minutes. 1,3-Cyclohexadione was used in place of ethyl acetoacetate in the absence of urea this methodology is giving hexahydro xanthene derivatives in good to excellent yields after 3-4 hours.Methods:DABCO salt 4 (5 mol%), 4-methoxybenzaldehyde (0.73 mmol) and urea (0.73 mmol) were stirred for 10 minutes at 80°C, then ethyl acetoacetate (1.5 equiv.) was added and reaction mixture was stirred at 80°C for specified time. The resulting solution was stirred continuously and progress of the reaction was followed by TLC. The crude reaction mixture was purified by flash column chromatography on silica gel (hexane/ethyl acetate (1:2)) to give pure desired product.Results:Reaction conditions of the Biginelli reaction were optimized using 4-methoxybenzaldehyde (0.73 mmol), urea (0.73 mmol), and ethyl acetoacetate (5 equiv.) as model substrates catalyzed by 1,4-Diazabicyclo [2.2.2] octane triflate (5 mol%) in a different solvents, screening of different catalysts and different temperatures. Neat condition was found to be the best for the Biginelli condensation and corresponding 3,4- dihydropyrimidinones was obtained in good to excellent yields. When the reaction was carried out with benzaldehyde derivatives and cyclohexane-1,3-dione in place of ethyl acetoacetate in the absence of urea, solely corresponding hexahydro xanthene derivatives were obtained in 61-91% yields.Conclusion:In conclusion, we have applied salts of 1,4-Diaza-bicyclo [2.2.2] octane as catalysts in the Biginelli condensation and corresponding 3,4-dihydropyrimidinones were obtained in 50- 99% yields under solvent free conditions. This methodology is having advantages like simple work-up; low loading of catalyst and reaction was performed at moderate temperature under solvent-free conditions.

1,3-Dibromo-5,5-dimethylhydantoin as a useful reagent for efficient synthesis of 3,4-dihydropyrimidin-2-(1H)-ones under solvent-free conditions

2009 ◽  
Vol 63 (1) ◽  
Author(s):  
Mohammad Abdollahi-Alibeik ◽  
Zahra Zaghaghi
Keyword(s):  
Microwave Irradiation ◽  
Ethyl Acetoacetate ◽  
Biginelli Reaction ◽  
Reaction Times ◽  
Solvent Free ◽  
Efficient Synthesis ◽  
One Pot ◽  
Aliphatic Aldehydes ◽  
Solvent Free Conditions ◽  
High Yields

AbstractEfficient syntheses of 3,4-dihydropyrimidin-2-(1H)-ones and the corresponding thioxo derivatives using 1,3-dibromo-5,5-dimethylhydantoin (DBH) catalysis of a one-pot three-component Biginelli reaction of aldehydes, ethyl acetoacetate, and urea or thiourea under microwave irradiation are described. The advantages of this method are its short reaction times, high yields of the products, inexpensive and commercially available catalyst, and solvent-free conditions. Typical isolated yields exceed 70 % for arylaldehydes (9 examples) and aliphatic aldehydes (2 examples).

Cholinium ionic liquids as cheap and reusable catalysts for the synthesis of coumarins via Pechmann reaction under solvent-free conditions

RSC Advances ◽  
2014 ◽  
Vol 4 (44) ◽  
pp. 22946-22950 ◽  
Author(s):  
Yuehua Zhang ◽  
Anlian Zhu ◽  
Qianqian Li ◽  
Lingjun Li ◽  
Yang Zhao ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Ethyl Acetoacetate ◽  
Catalytic Performance ◽  
Solvent Free ◽  
Reusable Catalyst ◽  
Pechmann Reaction ◽  
Solvent Free Conditions

Ionic liquid [N112OH][HSO4] was found to be an efficient and reusable catalyst for Pechmann reaction under solvent-free conditions. UV-vis studies suggested that the high catalytic performance of this catalyst was mainly due to its ability to increase the content of keto tautomer of ethyl acetoacetate.

Zirconium(IV) 4-sulphophenylethyliminobismethylphosphonate as an efficient and reusable catalyst for one-pot synthesis of 3,4-dihydropyrimidones under solvent-free conditions

2011 ◽  
Vol 65 (6) ◽  
Author(s):  
Xin-Bin Yang ◽  
Xiang-Kai Fu ◽  
Yu Huang ◽  
Ren-Quan Zeng
Keyword(s):  
Catalytic Activity ◽  
Elemental Analysis ◽  
Biginelli Reaction ◽  
Significant Loss ◽  
Solvent Free ◽  
Reusable Catalyst ◽  
One Pot ◽  
Efficient Catalyst ◽  
Solvent Free Conditions ◽  
Simple Filtration

AbstractZirconium(IV) 4-sulphophenylethyliminobismethylphosphonate (ZSBEDP) was prepared and characterised by elemental analysis, IR, TG-DSC, and XRD. ZSBEDP was found to be an efficient catalyst for the Biginelli reaction of aromatic aldehyde, ethyl acetoacetate, and urea or thiourea under solvent-free conditions so as to give 3,4-dihydropyrimidones in good to excellent yields. The catalyst can be separated by simple filtration and reused without significant loss of its catalytic activity.

scholarly journals Pumice as a Novel Nature Heterogeneous Catalyst for Synthesis of 3,4-dihydropyrimidine-2-(1H)-Ones/Thiones via Biginelli Reaction under Solvent-free Conditions

2021 ◽  
Author(s):  
Ali Mohamed ◽  
Lamya H. Al-Wahaibi ◽  
Antar Abdelhamid ◽  
Sayed Saber ◽  
Nadia Kanzi
Keyword(s):  
Heterogeneous Catalyst ◽  
Ethyl Acetoacetate ◽  
Biginelli Reaction ◽  
Thermal Conditions ◽  
Aromatic Aldehydes ◽  
Solvent Free ◽  
One Pot ◽  
Acetyl Acetone ◽  
Solvent Free Conditions ◽  
Work Up

Abstract: An efficient and environmentally Pumice as a new catalyst for designing of 3,4- dihydropyrimidin-2(1H) ones / thiones via one-pot multi component condensation of aromatic aldehydes, urea/ thiourea and ethyl acetoacetate or acetyl acetone in excellent yields (96-99 %). The advantages using of this new catalyst is very cheap, available, non-toxic, stable under thermal conditions, easy work-up, improved yields, the product of reaction is very pure without using chromatographic methods and solvent free conditions.

scholarly journals Metal- and solvent-free preparation of benzo[4,5]imidazo[1,2-a]pyrimidine derivatives catalysed by deep eutectic solvents

2021 ◽  
Vol 63 (3) ◽  
pp. 15-17
Author(s):  
Thuy-Duy Thi Nguyen ◽  
◽  
Anh Vy Truong ◽  
Hoang Phuong Tran ◽  
◽  
...  
Keyword(s):  
Ethyl Acetoacetate ◽  
Good Yield ◽  
Choline Chloride ◽  
Biginelli Reaction ◽  
Deep Eutectic Solvent ◽  
Environmentally Friendly ◽  
Deep Eutectic Solvents ◽  
Solvent Free ◽  
Pyrimidine Derivatives ◽  
Solvent Free Conditions

by an acidic deep eutectic solvent from choline chloride (ChCl) and phenol via the Biginelli reaction of 2-aminobenzimidazole, ethyl acetoacetate, and aldehydes has been developed under metal- and solvent-free conditions. The desired products were obtained in moderate to good yield (49-79%) and the DESs were known as an economical and environmentally friendly catalyst.

scholarly journals Biodiesel Production from Low-Quality Oils Using Heterogeneous Cesium Salts of Vanadium-Substituted Polyoxometalate Acid Catalyst

Catalysts ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1060
Author(s):  
Wenlei Xie ◽  
Chunli Gao ◽  
Hongyan Wang
Keyword(s):  
Solid Acid Catalyst ◽  
Acid Catalyst ◽  
Biodiesel Production ◽  
Molar Ratio ◽  
Emission Spectrometry ◽  
Solid Catalyst ◽  
Reusable Catalyst ◽  
Efficient Production ◽  
Gravimetric Analysis ◽  
Plasma Atomic Emission Spectrometry

This research aims at developing an efficient and reusable catalyst to improve biodiesel production processes. To achieve this, a vanadium-substituted polyoxometalate (POM) acid, namely H6PV3MoW8O40, was firstly prepared, and then the heterogenzation of the homogeneous Keggin-type heteropoly acids was performed by the partial proton substitution by monovalent large cesium cations with the formation of solid Cs2H4PV3MoW8O40 catalysts. Several techniques, such as X-ray diffractometer, Fourier transform infrared, coupled plasma–atomic emission spectrometry, Diffuse reflectance ultraviolet–visible spectrum, thermal gravimetric analysis and N2 adsorption–desorption techniques, were employed to characterize the as-prepared solid catalyst. The solid acid catalyst had the capacity to catalyze both the transesterification of soybean oil and esterification of free fatty acids (FFAs) simultaneously, providing an efficient production process for the production of biodiesel from low-quality oils. Under the operational conditions of a methanol/oil molar ratio of 30:1, a catalyst dosage of 5 wt.%, a reaction temperature of 140 °C, and a reaction duration of 8 h, an oil conversion of 92.2% was attained with the total FFA transformation to biodiesel. Furthermore, the catalyst could be reutilized for several cycles with no significant drop in its activity, thus having great potential for application with a bright perspective in the production of biodiesel, especially from low-quality oil feedstocks.

A green approach for an efficient preparation of 2,4-diamino-6-aryl-5-pyrimidinecarbonitriles using a TiO2–SiO2 nanocomposite catalyst under solvent-free conditions

2017 ◽  
Vol 72 (4) ◽  
pp. 241-247 ◽  
Author(s):  
Ahmad Rabiei ◽  
Shahrzad Abdolmohammadi ◽  
Faezeh Shafaei
Keyword(s):  
Low Cost ◽  
Condensation Reaction ◽  
Aromatic Aldehydes ◽  
Solvent Free ◽  
Molar Ratio ◽  
Reusable Catalyst ◽  
Green Approach ◽  
Solvent Free Conditions ◽  
Guanidine Nitrate ◽  
Nanocomposite Catalyst

AbstractWe report on the preparation of a series of 2,4-diamino-6-aryl-5-pyrimidinecarbonitriles, a new efficient protocol, via the condensation reaction of aromatic aldehydes, malononitrile, and guanidine nitrate using a TiO2–SiO2 nanocomposite with a molar ratio of 1:1 as a heterogeneous catalyst. The use of a low-cost and reusable catalyst under mild and solvent-free conditions, and simplicity in operation with easier isolation of the products in high to excellent yields are the main advantages of this highly versatile and eco-friendly protocol.

scholarly journals Three-component reaction of β-keto esters, aromatic aldehydes and urea/thiourea promoted by caffeine, a green and natural, biodegradable catalyst for eco-safe Biginelli synthesis of 3,4-dihydropyrimidin-2(1H)-ones/thiones derivatives under solvent-free conditions

2018 ◽  
Vol 83 (6) ◽  
pp. 673-684 ◽  
Author(s):  
Farzaneh Mohamadpour ◽  
Mojtaba Lashkari
Keyword(s):  
Biginelli Reaction ◽  
Reaction Times ◽  
Aromatic Aldehydes ◽  
Solvent Free ◽  
Solid Catalyst ◽  
One Pot ◽  
Keto Esters ◽  
Solvent Free Conditions ◽  
Three Component Reaction ◽  
High Yields

Caffeine was found to be a natural and green and biodegradable catalyst for the one-pot, three-component condensation Biginelli reaction of ?-keto esters, aromatic aldehydes and urea/thiourea to afford the corresponding 3,4-dihydropyrimidin-2(1H)-ones/thiones derivatives under solvent-free conditions. The remarkable features of this green procedure are high yields, short reaction times, simplicity of operation and work-up procedures, the availability and easy handling of this solid catalyst, avoidance of hazardous or toxic catalysts and organic solvents and economic availability of the catalyst.

1, 1’-Sulfinyldiethylammonium Bis (Hydrogen Sulfate) as a Recyclable Dicationic Ionic Liquid Catalyst for the Efficient Solvent-free Synthesis of 3, 4-Dihydropyrimidin-2(1H)-ones via Biginelli Reaction

2020 ◽  
Vol 23 (2) ◽  
pp. 157-167
Author(s):  
Zainab Ehsani-Nasab ◽  
Ali Ezabadi
Keyword(s):  
Ionic Liquid ◽  
Biginelli Reaction ◽  
Aromatic Aldehydes ◽  
Solvent Free ◽  
Hydrogen Sulfate ◽  
One Pot ◽  
Acidic Ionic Liquid ◽  
Brønsted Acidic Ionic Liquid ◽  
Solvent Free Conditions ◽  
Dicationic Ionic Liquid

Objective: A facile and efficient method for synthesis of 3, 4-dihydropyrimidin-2(1H)-ones via Biginelli reaction catalyzed by a novel dicationic Brönsted acidic ionic liquid, [(EtNH2)2SO][HSO4]2, has been successfully developed. Material and Method:: 3, 4-Dihydropyrimidin-2(1H)-ones were synthesized through one-pot condensation of aromatic aldehydes, ethyl acetoacetate, and urea under solvent-free conditions using [(EtNH2)2SO][HSO4]2 as a novel catalyst. The progress of the reaction was monitored by thin-layer chromatography (ethyl acetate / n-hexane = 1 / 5). The products have been characterized by IR, 1H NMR, 13C NMR, and also by their melting points. Results: In this research, a library of dihydropyrimidinone derivatives was synthesized via Biginelli reaction under solvent-free conditions at 120oC using [(EtNH2)2SO][HSO4]2 as a catalyst. Various aromatic aldehydes, as well as heteroaromatic aldehydes, were employed, affording good to high yields of the corresponding products and illustrating the substrate generality of the present method. In addition, the prepared dicationic Brönsted acidic ionic liquid can be easily recovered and reused. Conclusion: 1, 1’-Sulfinyldiethylammonium bis (hydrogen sulfate), as a novel dicationic ionic liquid, can act as a highly efficient catalyst for the synthesis of 3, 4-dihydropyrimidin-2(1H)-ones under solvent-free conditions.

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