Synthesis of 2,4,5-trisubstituted imidazoles catalyzed by [Hmim]HSO4 as a powerful Brönsted acidic ionic liquid

2008 ◽  
Vol 86 (3) ◽  
pp. 264-269 ◽  
Author(s):  
Ahmad R Khosropour
Keyword(s):  
Ionic Liquid ◽  
Room Temperature ◽  
Low Cost ◽  
Catalytic Amount ◽  
Room Temperature Ionic Liquid ◽  
Acidic Ionic Liquid ◽  
Brønsted Acidic Ionic Liquid ◽  
Green Procedure

An efficient and green procedure for the synthesis of 2,4,5-trisubstituted imidazoles with various aldehydes using a catalytic amount of 1-methylimidazolium hydrogenesulfate as an active and low cost Brönsted acidic room temperature ionic liquid has been developed. The ionic liquid was easily separated from the reaction mixture and was recycled five times without any loss in activity.Key words: ionic liquid, 2,4,5-trisubstituted imidazoles, [Hmim]HSO4, aldehyde, benzil.

scholarly journals Mild and Efficient Tunable Brønsted Acidic Ionic Liquid Catalyzed O-Acetylation and O-Trimethylsilylation with Trimethylsilyl Acetate (TMSOAc) and Hexamethyldisilazane (HMDS)

Catalysts ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 825
Author(s):  
Amit Ravindra Pantawane ◽  
Mayur Thul ◽  
Yi-Jyun Lin ◽  
Michelle Lin ◽  
Wesley Lin ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Room Temperature ◽  
Visible Spectroscopy ◽  
Acidic Ionic Liquid ◽  
Post Process ◽  
Brønsted Acidic Ionic Liquid ◽  
Acidic Ionic Liquids ◽  
Uv Visible ◽  
Work Up

This report discloses a mild and efficient O-acetylation using easily accessible TMSOAc as a novel acetyl reagent and O-trimethylsilylation using HMDS for various alcohols catalyzed by tunable Brønsted acidic ionic liquids (TBAILs). Imidazolium-based TBAILs were prepared by a two-step atom-economic reaction and acidities measured by using UV-visible spectroscopy. Both protections for alcohols were accomplished at room temperature with good to excellent yields, while the products and TBAILs were separated by simple work-up for O-silylation and column chromatography for O-acetylation. Notably, with the simple post-process, TBAILs catalyst in this solvent free method easily recovered and recycled several times without significant degradation.

Ionic liquid promoted simple and efficient synthesis of β-enamino esters and β-enaminones from 1,3-dicarbonyl compounds – One-pot, three-component reaction for the synthesis of substituted pyridines

2005 ◽  
Vol 83 (10) ◽  
pp. 1746-1751 ◽  
Author(s):  
Ganesan Karthikeyan ◽  
Paramasivan T Perumal
Keyword(s):  
Ionic Liquid ◽  
Room Temperature ◽  
Ammonium Acetate ◽  
Efficient Synthesis ◽  
One Pot ◽  
Dicarbonyl Compounds ◽  
Acidic Ionic Liquid ◽  
Brønsted Acidic Ionic Liquid ◽  
Three Component Reaction ◽  
Substituted Pyridines

A facile enamination of 1,3-dicarbonyl compounds with amines has been developed that affords good to excellent yields of β-enamino esters and β-enaminones using Brønsted acidic ionic liquid 1-methylimidazolium trifluoroacetate ([Hmim]+Tfa–) at room temperature. This methodology has been extended for the synthesis of substituted pyridines in excellent yield by a one-pot, three-component reaction of 1,3-dicarbonyl compounds, ammonium acetate, and alkynone in the presence of [Hmim]+Tfa–.Key words: ionic liquid, β-enaminones, β-enamino esters, 1,3-dicarbonyl compounds, amines, pyridines.

Efficient and Convenient Procedure for Protection of Hydroxyl Groups to the THP, THF and TMS Ethers and Oxidation of these Ethers to their Aldehydes or Ketones in [BPy]FeCl4 as a Low Cost Room Temperature Ionic Liquid

2006 ◽  
Vol 61 (3) ◽  
pp. 326-330 ◽  
Author(s):  
Ahmad R. Khosropour ◽  
Mohammad M. Khodaei ◽  
Sattar Ghaderi
Keyword(s):  
Ionic Liquid ◽  
Room Temperature ◽  
Low Cost ◽  
Room Temperature Ionic Liquid ◽  
Hydroxyl Groups ◽  
Convenient Procedure

AbstractAlcohols were converted to the corresponding THP, THF or TMS ethers in high to excellent yields in 1-n-butylpyridinium chloroferrate media as a stable and low cost room temperature ionic liquid. In addition, oxidation of these ethers to their aldehydes or ketones without any overoxidation reactions in this ionic liquid was also performed.

scholarly journals Corrosion Performance of Austenitic Stainless Steel Bipolar Plates for Nafion- and Room-Temperature Ionic-Liquid-Based PEMFCs

2012 ◽  
Vol 5 (1) ◽  
pp. 47-52 ◽  
Author(s):  
Claudio Mele ◽  
Benedetto Bozzini
Keyword(s):  
Stainless Steel ◽  
Ionic Liquid ◽  
Austenitic Stainless Steel ◽  
Room Temperature ◽  
Low Cost ◽  
Corrosion Current ◽  
Room Temperature Ionic Liquid ◽  
Bipolar Plates ◽  
Pitting Potential ◽  
Aisi 304

In this paper we study the corrosion of AISI 304 austenitic stainless steel PEMFC bipolar plates in aqueous and room-temperature ionic-liquid electrolytes. The anodic potential thresholds and dynamics have been investigated by electrochemical (potentiodynamic and potentiostatic) and in situ spectroelectrochemical methods (visible electroreflectance and VIS-UV spectroellipsometry). We measured the values of damage potentials and we followed the time evolution of corrosion current and reflectivity above and below the pitting potential, obtaining an accurate characterisation of the surface conditions under oxidative attack. The ability of AISI 304 to repassivate in Cl¯-containing aqueous solution as well as the amount of residual surface damage have been assessed quantitatively by following electrode reflectivity under applied potential. Outstanding inertness of AISI 304 in [BMP][TFSA] was proved. The results of this work show that low-cost AISI 304 is a promising interconnect material for both Nafion- and RTIL-based PEMFCs.

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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