Semipreparative scale enantioseparation of racemic amine and amino ester hydrogen perchlorate salts using a silica gel-bound optically active di-tert-butylpyridino-18-crown-6 ligand.

We report herein results on the enantioseparation of selected racemic amine and amino ester hydrogen perchlorate salts using a silica gel-bound optically pure chiral di-tert-butylpyridino-18-crown-6 ligand (R,R)-1. The effect of solvent composition was studied using appropriate binary and ternary solvent mixtures as eluents. We found that acetonitrile/ methanol/ dichloromethane (MeCN/MeOH/CH2 Cl2 ) ternary solvent mixtures gave better enantioseparations for the racemic salts using chiral stationary phase (R,R)-1 than any of the binary ones. In the present paper we also describe the studies of chromatographic parameters such as loading, flow rate and eluent polarity.