Enantioselective liquid-liquid extraction of zopiclone was conducted by employing a series of (R)-mandelic acid esters as chiral extractants. The effects of concentration of extractant, concentration of zopiclone, type of organic solvent, pH value, and temperature on the extraction efficiency were investigated. (R)-o-chloromandelic acid propyl ester was demonstrated to be an efficient chiral extractant for zopiclone resolution with a maximum enantioselectivity of 1.6.
Keywords: chiral recognition; enantiomer; enantioselective extraction; mandelic acid ester; zopiclone.
© 2013 Wiley Periodicals, Inc.