Reversed‐phase planar chromatography of some enantiomeric amino acids and oxazolidinones

Abstract

The resolution of two enantiomeric amino acids and four structurally related oxazolidinones was evaluated by reversed-phase planar chromatography using both home-made microcrystalline cellulose triacetate (MCTA) layers and mobile phase additivies, such as beta-cyclodextrins (beta-Cy), modified alpha, beta, gamma cyclodextrins and bovine serum albumin (BSA), on commercially available RP-18W/F254 and SilC18-50/UV254 plates. All the enantiomers were partially or baseline resolved by at least one of the chiral phases tested. Densitograms of optical antipodes and their mixtures were measured on MCTA layers developed with hydroalcoholic solvents.

Structure and Substituent Effects on Retention and Chiral Resolution of Ketones and Alcohols on Microcrystalline Cellulose Triacetate Plates

“…More specifically, this CSP shows a strong chiral recognition towards the optical antipodes with both the carbonyl group and the stereogenic centre on a rigid ring structure, such as flavanones [7,8] and 2-oxazolidinones [6,7,11]. The enantiomers of 2-methyl and 3-methyl-1-indanone were also separated on MCTA layers [7] and Table 1 shows a comparison of their retention and resolution data with those obtained in this study for numerous structurally related tetralones and indanones.…”

“…Several racemates with a carbonyl group in a or b-position with respect to the stereogenic centre were resolved on MCTA layers with aqueous-alcoholic mixtures as eluents [5][6][7][8]11]. …”

“…Among the various TLC applications of chiral stationary phases (CSPs), the most important were obtained on microcrystalline cellulose triacetate (MCTA), using both ready-touse plates [2,3] and non-commercial plates [4][5][6][7][8][9][10][11].…”

“…MCTA is an inexpensive material that does not adsorb UV light, enabling analyte detection and quantification by UV-densitometry; it was used for the resolution of more than 65 pairs of enantiomers eluting with aqueous-alcoholic mixtures containing methanol, ethanol or 2-propanol [2][3][4][5][6][7][8][9][10][11]. More specifically, a remarkable selectivity (a = 2.64) was observed for Troger's base, which contains an asymmetric nitrogen atom (a tertiary amine rigidly locked in the ring) and is the usual standard for testing the resolving power of different chiral selectors [12].…”

Evaluation of separation parameters for selected organophosphorus fungicides of forensic importance by RP-HPTLC

“…The R M values were then obtained using the equation R M = log(1/R F − 1) [16][17][18]. ∆R F , selectivity (α) [19][20][21], and the pair separation constant (R F α ) [21,22] were then calculated for all the densitograms by using eqs (1)- (3), respectively:…”