Preparative enantioseparation of propafenone by counter‐current chromatography using di‐ n ‐butyl l ‐tartrate combined with boric acid as the chiral selector

This paper extends the research of the utilization of borate coordination complexes in chiral separation by counter‐current chromatography ( CCC ). Racemic propafenone was successfully enantioseparated by CCC with di‐ n ‐butyl l ‐tartrate combined with boric acid as the chiral selector. The two‐phase solvent system was composed of chloroform/ 0.05 mol/L acetate buffer pH 3.4 containing 0.10 mol/L boric acid (1:1, v/v), in which 0.10 mol/L di‐ n ‐butyl l ‐tartrate was added in the organic phase. The influence of factors in the enantioseparation of propafenone were investigated and optimized. A total of 92 mg of racemic propafenone was completely enantioseparated using high‐speed CCC in a single run, yielding 40–42 mg of ( R )‐ and ( S )‐propafenone enantiomers with an HPLC purity over 90–95%. The recovery for propafenone enantiomers from fractions of CCC was in the range of 85–90%.