Resolution and analysis of enantiomers of amphetamines by liquid chromatography on a chiral stationary phase: collaborative study.

A rapid, accurate method for separating and determining the enantiomeric composition of amphetamine bulk drug and commercial preparations was developed and subjected to collaborative study. Amide derivatives of the amphetamine enantiomers are formed by using achiral 2-naphthoyl chloride. The resulting enantiomeric amides are then chromatographed on a commercially available chiral stationary phase with hexane-isopropyl alcohol-acetonitrile (97 + 3 + 0.

Resolution of enantiomeric amides on a cellulose tribenzoate chiral stationary phase. Mobile phase modifier effects on retention and stereo-selectivity.

The effect of the steric structure and concentration of the mobile phase modifier on the retention (kappa') and stereoselectivity (alpha) of a series of enantiomeric amides has been investigated. The amides were chromatographed on a commercially available cellulose tribenzoate chiral stationary phase (CSP) using mobile phases composed of hexane and two homologous series of alcohols: methanol, ethanol, 1-propanol and 2-propanol, 2-butanol, 2-pentanol, 2-hexanol. The results of the study indicate that the alcoholic mobile phase modifiers compete with the solutes for achiral and chiral binding sites and that the steric bulk around the hydroxyl moiety of the modifier plays a role in this competition.

Resolution of enantiomeric amides on a Pirkle-type chiral stationary phase. A comparison of subcritical fluid and liquid chromatographic approaches.

Subcritical and supercritical fluid chromatography (SubFC and SFC) have been evaluated for the resolution of an homologous series of enantiomeric amides. The solutes were the 2-naphthoyl amides of an homologous series of amines, ranging from 2-aminobutane to 2-aminoctane, and the p-methyl-, p-methoxy- and p-chlorophenylamides of 2-aminoheptane. The chiral stationary phase (CSP) used was the covalent form of (R)-N-(3,5-dinitrobenzoyl)phenylglycine.

Steric and electronic effects in the resolution of enantiomeric amides on a commercially available Pirkle-type high-performance liquid chromatographic chiral stationary phase.

The steric and electronic effects in the resolution of enantiomeric amides on a commercially available (R)-N-(3,5-dinitrobenzoyl)phenylglycine chiral stationary phase (CSP) have been investigated. Several homologous series of enantiomeric amides were synthesized from alkyl and aromatic amines and from alkyl and aromatic acids. The results of the study indicate that chiral recognition is based on the formation of diastereomeric solute-CSP complexes that are due to attractive interactions located on a single bond in both the solute and CSP and on steric interactions within the complexes.

Resolution of enantiomeric amides on a cellulose-based chiral stationary phase. Steric and electronic effects.

A series of enantiomeric amides were resolved on a commercially available chiral stationary phase (CSP) consisting of cellulose tribenzoate coated on macroporous silica. The amides were synthesized from several homologous series of aliphatic and aromatic chiral amines and a series of aliphatic chiral acids. The results of the study indicate that the formation of the solute-CSP diastereomeric complex is based on a combination of hydrogen bonding, pi-pi and amide dipole interactions.