High‐performance liquid chromatography separation of enantiomers of mandelic acid and its analogs on a chiral stationary phase

Abstract

The enantiomers of mandelic acid and its analogs have been chromatographically separated on a chiral stationary phase (CSP) derived from 4-(3,5-dinitrobenzamido) tetrahydrophenanthrene. The rationale of separations of these compounds is discussed with respect to the method development for determining enantiomeric purity and possibility of obtaining enantiomerically pure materials by high-pressure liquid chromatography. The relationship of analyte structure to the extent of enantiomeric separation has been examined and separation factors (alpha) are presented for various groups of structurally related compounds. Chiral recognition models have been suggested to account for the observed separations. These models provide mechanistic insights into the chiral recognition process.

Unexpected enantioseparation of mandelic acids and their derivatives on 1,2,3‐triazolo‐linked quinine tert‐butyl carbamate anion exchange‐type chiral stationary phase

“…Similarly, the application portfolios of commercially available CSPs rarely include mandelic acid and their derivatives. Recently, Ahuja and coworkers have designed a low-molecular selector based on a tetrahydrophenatrene core for mandelics; however, it showed no or little selectivity toward simple mandelic acid and their derivatives [23]. By a different approach, Hofstetter and coworkers demonstrated a novel, highly efficient immunochromatographic method for enantioseparation of some a-hydroxyacids by immobilization of a monoclonal antibody produced against the D-enantiomer of mandelic acid [24].…”

“…They also found application in medicinal, cosmetic, and agrochemical industry [17,18]. Enantioselective analytics of mandelic acid and their derivatives by HPLC is not very frequently reported [19][20][21][22][23]. Typically, methods of their enantioseparation involve ligand-exchange or chiral additive approaches and most of them suffer from a need of derivatization, low selectivity, or long analysis times [22].…”

Betamethasone‐based chiral electrochemical sensor coupled to chemometric methods for determination of mandelic acid enantiomers

“…Analysis of MA, a chiral α‐hydroxy carboxylic acid, is essential, owing to its important role in natural product synthesis and drug development . Using the electrochemical sensors for enantioselective sensing has several advantages over chromatographic and spectrophotometric techniques, such as simplicity, flexibility in design, ease of chemical modification, small size, low cost, rapid detection, and possibility of real‐time analysis . In spite of these advantages, their applicability for the stereoselective sensing of chiral compounds in their mixtures is rather limited because of significant overlapping of their polarograms or voltammograms.…”

“…Up to now, various sensing interfaces have been developed for discrimination of mandelic acid (MA) enantiomers, including diastereomeric crystallization, 1 high-performance liquid chromatography, 2,3 quartz crystal microbalance, 4 fluorescence detection, [5][6][7][8] and electrochemical detection. 4,[9][10][11][12][13][14][15] Analysis of MA, a chiral α-hydroxy carboxylic acid, is essential, owing to its important role in natural product synthesis and drug development.…”

“…16 Using the electrochemical sensors for enantioselective sensing has several advantages over chromatographic and spectrophotometric techniques, such as simplicity, flexibility in design, ease of chemical modification, small size, low cost, rapid detection, and possibility of real-time analysis. 2 In spite of these advantages, their applicability for the stereoselective sensing of chiral compounds in their mixtures is rather limited because of significant overlapping of their polarograms or voltammograms. In recent years, there has been high interest in applying chemometric tools for electroanalytical responses to solve the problem of overlapping electrochemical signals.…”