Beneficial Contribution of Biosourced Ionic Liquids and Microwaves in the Michael Reaction

Abstract

We developed a synthesis of chiral ionic liquids from proline and one of its derivatives. Nine chiral ionic liquids were synthesized with yields from 78% to 95%. These synthesized ionic liquids played two roles in Michael reactions, as solvents, and as basic catalysts, where the ionic phase could also be reused at least five times without loss of activity. The yields up to 99% were improved by increasing the amount of dimethylmalonate from 1.2 equivalents to 3 or 4 equivalents. Furthermore, the reaction time could be reduced from 24 h to 45 min through microwaves activation.

L-Proline-Based Natural Deep Eutectic Solvents as Efficient Solvents and Catalysts for the Ultrasound-Assisted Synthesis of Aurones via Knoevenagel Condensation

“…Moreover, proline-based ionic liquids can be successfully applied as solve basic catalysts for a Michael addition reaction between chalcone and dimethyl ma as shown in the work of Bacha et al [14]. Proline nitrate, another proline-based io uid, was recently reported to effectively catalyze the synthesis of pyrimidine deri in various solvents, as well as in H2O [15].…”

Ionic Liquids in Catalysis

“…This new approach, which is characterized by the replacement of conventional acids and organometallic compounds with ionic liquids, was described by Chrobok's research group [28]. Bouquillon et al presented the synthesis of a series of biobased ionic liquids with natural carboxylates (proline-based ionic liquids) [29]. These compounds were employed as a solvent and basic catalyst in Michael reactions.…”