Organic Reactions in Ionic Liquids: Ionic Liquid Promoted Knoevenagel Condensation of Aromatic Aldehydes with (2-Thio)barbituric Acid.

ChemInform ◽  
2005 ◽  
Vol 36 (20) ◽  
Author(s):  
Yi Hu ◽  
Zhen-Chu Chen ◽  
Zhang-Gao Le ◽  
Qin-Guo Zhang
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Barbituric Acid ◽  
Knoevenagel Condensation ◽  
Aromatic Aldehydes ◽  
Organic Reactions

Organic Reactions in Ionic Liquids: Ionic Liquid-Promoted Efficient Synthesis of N-Alkyl and N-Arylphthalimides.

ChemInform ◽  
2005 ◽  
Vol 36 (41) ◽  
Author(s):  
Zhang-Gao Le ◽  
Zhen-Chu Chen ◽  
Yi Hu ◽  
Qin-Guo Zheng
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Organic Reactions ◽  
Efficient Synthesis

Synthesis of 1,8-dioxo-octahydro-xanthene and tetrahydrobenzo[b]pyran derivatives promoted by two bis-imidazolium-based ionic liquids

2021 ◽  
Vol 08 ◽  
Author(s):  
Maryam Shirzad ◽  
Mitra Nasiri ◽  
Nader Daneshvar ◽  
Farhad Shirini ◽  
Hassan Tajik
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Knoevenagel Condensation ◽  
Reaction Rates ◽  
Xanthene Derivatives ◽  
Acidic Ionic Liquids ◽  
Dicationic Ionic Liquids ◽  
Acidic Nature ◽  
Work Up ◽  
Reaction Media

Aim and objective: In this work, we have prepared two bis-dicationic ionic liquids with the same cationic core (Bis-imidazole) and different counter-anions using sulfuric acid and perchloric acids. After that, the efficiency and ability of these compounds as catalysts were investigated and compared in the promotion of Knoevenagel condensation and synthesis of benzo[b]pyran derivatives to see the effect of the anionic counter-part in the reaction. Material and method: In a 25 mL round-bottomed flask, a mixture of aldehyde (1.0 mmol), 1,3-cyclodicarbonyl (2.0 mmol) and the desired amount of the mentioned acidic ionic liquids was heated at 90°C in the absence of solvent (Reaction A) or In a 25 mL round-bottomed flask, a mixture of aldehyde (1.0 mmol), 1,3-cyclodicarbonyl (1.0 mmol), malononitrile, (1.1 mmol) and optimized amounts of the ionic liquid in water (3.0 mL) was heated at 80°C (Reaction B) for the appropriated time. After the completion of the reactions which were monitored by TLC (n-hexane: EtOAc; 3:1), 10 mL of water was added and the mixture was stirred for 2 minutes. Then, the products were separated by filtration and were washed several times with water. After drying, the pure products were obtained while there was no need to further. Results: Comparison of the obtained results from both of the ionic liquids revealed that [H2-Bisim][HSO4]2 because of its more acidic structure had a more catalytic activity for the preparation of 1,8-dioxo-octahydro-xanthene derivatives but [H2-Bisim][ClO4]2 was relatively more efficient for the synthesis of tetrahydrobenzo[b]pyran derivatives since the stronger acidic nature of [H2-Bisim][HSO4]2 may prevent the simple activation of malononitrile in the reaction media. Conclusion: In this study, we have introduced efficient methods for the synthesis of 1,8-dioxo-octahydro-xanthene and tetrahydrobenzo[b]pyran derivatives in the presence of catalytic amounts of [H2-Bisim][ClO4]2 and [H2-Bisim][HSO4]2 These methods have several advantages such as ease of preparation and handling of the catalysts, high reaction rates, excellent yields, eco-friendly procedures and simple work-up.

One-Pot Syntheses of 2H-Indazolo[2,1-B] Phthalazine-Triones Catalyzed by Ionic Iiquid

2011 ◽  
Vol 332-334 ◽  
pp. 1884-1887
Author(s):  
Fang Yang ◽  
Hong Jun Zang ◽  
Qing Kai Wang ◽  
Bo Wen Cheng ◽  
Yuan Lin Ren ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Condensation Reaction ◽  
Aromatic Aldehydes ◽  
One Pot

A simple and efficient one-pot method for the preparation of 2H-indazolo [2,1-b] phthalazine-triones from phthalhydrazide, dimedone and aromatic aldehydes has been developed using ionic liquids as catalysts. Two ionic liquid catalysts are described, and the ionic liquid [(CH2)4SO3HMIM]HSO4 catalyst is found to be more effective than [HMIM]HSO4 for this condensation reaction.

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