1,3-Dibromo-5,5-diethylbarbituric acid as an efficient catalyst for the protection of various alcohols with HMDS under solvent-free conditions

2007 ◽  
Vol 8 (6) ◽  
pp. 917-920 ◽  
Author(s):  
Ardeshir Khazaei ◽  
Mohammad Ali Zolfigol ◽  
Zahra Tanbakouchian ◽  
Morteza Shiri ◽  
Khodabakhsh Niknam ◽  
...  
Keyword(s):  
Solvent Free ◽  
Efficient Catalyst ◽  
Solvent Free Conditions ◽  
Diethylbarbituric Acid

Preparation and Characterization of a Novel Room Temperature Dicationic Ionic Liquid and its Application in the Synthesis of Xanthenediones Under Solvent-Free Conditions

2018 ◽  
Vol 21 (8) ◽  
pp. 602-608 ◽  
Author(s):  
Zainab Ehsani-Nasab ◽  
Ali Ezabadi
Keyword(s):  
Ionic Liquid ◽  
Room Temperature ◽  
Reaction Times ◽  
Significant Loss ◽  
Solvent Free ◽  
Acidity Function ◽  
Efficient Catalyst ◽  
Solvent Free Conditions ◽  
Hammett Acidity Function ◽  
Dicationic Ionic Liquid

Aim and Objective: In the present work, 1, 1’-sulfinyldiethylammonium bis (hydrogen sulfate) as a novel room temperature dicationic ionic liquid was synthesized and used as a catalyst for xanthenediones synthesis. Material and Method: The dicationic ionic liquid has been synthesized using ethylamine and thionyl chloride as precursors. Then, by the reaction of [(EtNH2)2SO]Cl2 with H2SO4, [(EtNH2)2SO][HSO4]2 was prepared and after that, it was characterized by FT-IR, 1H NMR, 13C NMR as well as Hammett acidity function. This dicationic ionic liquid was used as a catalyst for the synthesis of xanthenediones via condensation of structurally diverse aldehydes and dimedone under solvent-free conditions. The progress of the reaction was monitored by thin layer chromatography (ethyl acetate/n-hexane = 3/7). Results: An efficient solvent-free method for the synthesis of xanthenediones has been developed in the presence of [(EtNH2)2SO][HSO4]2 as a powerful catalyst with high to excellent yields, and short reaction times. Additionally, recycling studies have demonstrated that the dicationic ionic liquid can be readily recovered and reused at least four times without significant loss of its catalytic activity. Conclusion: This new dicationic ionic liquid can act as a highly efficient catalyst for xanthenediones synthesis under solvent-free conditions.

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.

Formylation of amines and alcohols using aminopropylated mesoporous SBA-15 silica (APMS) as an efficient and recyclable catalyst

2011 ◽  
Vol 76 (12) ◽  
pp. 1979-1990 ◽  
Author(s):  
Reihaneh Malakooti ◽  
Sara Sobhani ◽  
Nasrin Razavi ◽  
Soheila Shafiei ◽  
Rezvan Mokhtari
Keyword(s):  
Formic Acid ◽  
Recyclable Catalyst ◽  
Solvent Free ◽  
Efficient Catalyst ◽  
Solvent Free Conditions

Aminopropylated mesoporous SBA-15 silica (APMS) is introduced as a new, recyclable and efficient catalyst for the formylation of a variety of amines and alcohols by using readily available formic acid under solvent-free conditions.

Copper(ii) carboxymethylcellulose (CMC-CuII) as an efficient catalyst for aldehyde–alkyne–amine coupling under solvent-free conditions

RSC Advances ◽  
2016 ◽  
Vol 6 (97) ◽  
pp. 94399-94407 ◽  
Author(s):  
Xiaoping Liu ◽  
Bijin Lin ◽  
Zhuan Zhang ◽  
Hao Lei ◽  
Yiqun Li
Keyword(s):  
Solvent Free ◽  
Efficient Catalyst ◽  
Co Catalyst ◽  
Solvent Free Conditions ◽  
A3 Coupling ◽  
Amine Coupling

A novel heterogeneous Cu(ii) carboxymethylcellulose catalyst was prepared and successfully employed in the A3 coupling without using any co-catalyst, other additives, bases under solvent-free conditions.

A novel inorganic–organic nanohybrid material H4SiW12O40/pyridino-MCM-41 as efficient catalyst for the preparation of 1-amidoalkyl-2-naphthols under solvent-free conditions

2015 ◽  
Vol 44 (20) ◽  
pp. 9596-9609 ◽  
Author(s):  
R. Tayebee ◽  
M. M. Amini ◽  
M. Akbari ◽  
A. Aliakbari
Keyword(s):  
Solvent Free ◽  
One Pot ◽  
Efficient Catalyst ◽  
Solvent Free Conditions ◽  
The One ◽  
Substituted 1 ◽  
Nanohybrid Material ◽  
Mcm 41

A new inorganic–organic nanohybrid material was prepared and performed as an efficient catalyst for the one-pot multi-component synthesis of different substituted 1-amidoalkyl-2-naphthols under solvent-free conditions.

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