Synthesis of Biscoumarins Using Recyclable and Biodegradable Task-Specific Ionic Liquids

Abstract

In the frame of research that examines the use of task-specific ionic liquids (ILs) for developing green methodologies toward novel bioactive compounds, ethanolamine-derived ILs were synthesized and used as solvents and catalysts in a domino Knoevenagel−Michael reaction. After extended optimization studies regarding the most important reaction parameters such as reaction time, temperature, and molar ratio of reactants, it was ascertained that the reaction between 4-hydroxy-coumarin and various benzaldehydes in the synthesized ILs proceeded smoothly at 40 °C in 3 h, providing the desired biscoumarins in very satisfactory yields (up to 97%) and high purity after simple workup. The task-specific ILs were recycled and reused three times without a noticeable decrease in their catalytic activity. Moreover, the biodegradability potential of the synthesized ILs has been investigated by applying the biological oxygen demand (BOD-5) closed bottle test. The results indicated that organic carbon was biodegraded up to 59% within five days.

Hydroxyl ammonium ionic liquids as media for biocatalytic oxidations

“…Biodegradability assessment of ILs have been examined by measuring the Biochemical Oxygen Demand (BOD) [1], [2]. The determination of the biodegradability level of organic substances such as ILs is essential in order to estimate their environmental impact.…”

Separation of the ethanol/water azeotropic mixture using ionic liquids and deep eutectic solvents

“…Hydroxyl ammonium ILs were prepared by neutralization of a carboxylic acid with ethanolamine as described in our previous work for analogous compounds [19]. Ethanolamine (0.5 mol, 30.2 mL) was placed in a two necked round-bottomed flask equipped with a reflux condenser and a dropping funnel.…”

Sustainable and Eco‐Friendly Method for the Synthesis of Some Bioactive Derivatives of Biscoumarin and Pyrano[3,2‐c]Chromene‐3‐Carbonitrile Using Taurine, as the Catalyst

“…The main method for the preparation of biscomarin derivatives is the Knoevenagel‐Michael reaction. Because of the importance of biscoumarins essentially bis(4‐hydroxycoumarin) in the mentioned fields, many catalysts in various conditions have been introduced for the preparation of them such as [bmim]BF 4 , SDS, [PSebim][OTf], propane‐1,2,3‐triyl tris(hydrogen sulfate), [pyridine–SO 3 H]Cl, phospho sulfonic acid, cellulose sulfonic, W‐doped ZnO nanocomposite, Bi(NO 3 ) 3 ⋅5H 2 O, choline hydroxide, o ‐benzenedisulfonimide, P 4 VPy–CuO‐NPs, sulfonated rice husk ash, silica‐Bonded N ‐propylpiperazine sodium n ‐propionate, boron‐sulfuric acid Nanoparticles, P 4 VPy‐BuSO 3 H−X(AlCl 3 ), 4‐(dimethylamino)pyridine, and piperidine …”