Sub- and Supercritical Chiral Separation of Racemic Compounds on Columns with Stationary Phases Having Different Functional Groups

Abstract

Separation of the enantiomers of each of three different racemates, neutral rac-a a-tetralol, acidic rac-2-phenylpropionic acid, and basic rac-1-phenylethylamine, using subcritical and supercritical fluid chromatography with two different chiral stationary phases, heptakis(2,3,6-tri-O-methyl)-b b-cyclodextrin (Sumichiral OA-7500 column) and tris(3,5-dimethylphenylcarbamate) of amylose (Chiralpak AD-H column), was compared. The elution order of the enantiomers of the three racemates was determined, and the effects of the type of alcohol modifier, column oven temperature, mobile phase composition, flow rate, and pressure were examined. The most appropriate column oven temperature depended on both the type of alcohol modifier and the compound analyzed. Lower alcohol content improved the peak separation of both rac-a a-tetralol on the Sumichiral OA-7500 column and rac-1-phenylethylamine on the Chiralpak AD-H column, while the same phenomenon was not observed with either rac-a a-tetralol or rac-2-phenylpropionic acid on the Chiralpak AD-H column. Decreasing outlet pressure improved the peak separation obtained with rac-2-phenylpropionic acid, but had little effect on either rac-a atetralol or rac-1-phenylethylamine.

Chiral separation of phospine‐containing α‐amino acid derivatives using two complementary cellulosic stationary phases in supercritical fluid chromatography

“…This is in accordance with some past studies in enantioselective SFC. [21][22][23] On another hand other studies show totally different retention variations when the alcohol modifier is changed, 24,25 thus the effect of alcohol nature on retention in chiral SFC seems to be compound-dependent and no general conclusions should be drawn from the previous observations. Separation factors a were generally enhanced by replacing methanol by ethanol, then isopropanol, apart for PBzt where a increased when methanol was replaced by ethanol but decreased with isopropanol.…”

Supercritical fluid chromatography for the enantioseparation of pharmaceuticals

“…sulphate groups, alters the enantioselectivity. Although this type of chiral selector is extensively used in chiral capillary electrophoresis as mobile phase additive, and in chiral gas chromatography coated on the capillary wall, successful applications in SFC using this selector coated on a CSP have also been reported (Table 2) [38][39][40][41][42]. However the formation of enantioselective inclusion complexes might be hindered by the apolar carbon dioxide, competing also for the hydrophobic cavity of the cyclodextrins [37,42,43].…”

Separation of Racemic Chiral Drugs Using Immobilized CHIRALPAK IA: Methodology for Preparative Scale Development

“…Chromatography using chiral stationary phases (CSPs) has proven to be the most useful technique in the field of chiral separation (6)(7)(8). Various CSPs have been developed to separate the different chiral compounds.…”

“…Methocarbamol is a muscle relaxant and used in the h treatment of injuries and other painful muscular conditions. The last studied compound, a-Tetralol is a secondary chiral alcohol and its enantiomer R-a-Tetralol is used as a precursor for calcium antagonists commonly utilized in drugs for the treatment of hypertension and angina pectoris (8,27,28).…”