Mandelate and prolinate ionic liquids: synthesis, characterization, catalytic and biological activity

A group of quaternary ammonium mandelates and l-prolinates, as ionic liquids, were synthesized and characterized. The prepared salts were soluble in water and showed high surface activity. The described synthesis of l-prolinate was simple and the obtained ionic liquid contained a chiral anion. l-Prolinate in CH₂Cl₂ was employed for the asymmetric Michael addition of a ketone to nitrostyrene. A yield of 60%, enantioselectivity (upto 50% ee), and good diastereoselectivity (syn/anti ratio of up to 90:10) were obtained for the asymmetric addition of cyclohexanone. These novel ionic liquids proved to be very effective anti-microbial and anti-fungal agents, especially didecyldimethylammonium l-prolinate. Additionally, it was found that phytotoxicity can be a useful tool in assessing the optical forms of ionic liquids.