Preparative Chromatography - The Preparative Separation of the Enantiomers of Chlorokynurenine > Page 72


A summary of the purities and yields of the two isomers is shown in Table 2. It is clear that although the separation involves the resolution of two chemically very similar compounds, tens of milligrams of material could be separated in relatively high states of purity employing a column only 25 cm long and less that an inch in diameter.

Table 2. Summary of the Purity and Yield from the Separation of the Isomers of Nicardipine


Final Results Peak 1 Peak 2
Purity 99 % 99 %
Yield 95% 90 %

It should be emphasized that the success of this preparative separation depended, not on high column efficiencies, or, for that matter, on a particularly large column, but on the selection of a phase system that provided a high retention ratio between the two isomers. The required selectivity was achieved by firstly choosing a stationary phase with strong chiral interactive properties and secondly by choosing the best complementary solvent system that would provide strong differential interaction between the isomers and the two phases.