Dehydroabietic acid-based chiral ionic liquids: Their synthesis and potential enantiomeric recognition ability

Several new chiral imidazolinium ionic liquids (CILs) have been synthesized by using optically pure dehydroabietic acid (DA) as the chiral precursor. Their enantiomeric recognition abilities were measured using rac-mandelic acid n-Bu4N salt as the substrate by NMR spectroscopy. Based on the structure-interaction relationships, the bulky anion and the side chain linking the DA group to the imidazole ring have crucial effects on CIL recognition. The H-1 NMR measurements indicated that [MimMeDA]NTf2 exhibits good and versatile molecular recognition ability. The new DA-based CILs reported here may be interesting chiral media for enantioselective reactions and useful in enantiomeric separations. (C) 2020 Elsevier Ltd. All rights reserved.