High-performance liquid chromatographic separation of paclitaxel intermediate phenylisoserine derivatives on macrocyclic glycopeptide and cyclofructan-based chiral stationary phases

• Enantioseparation of phenylisoserine analogs on macrocyclic glycopeptide and cyclofructan-based CSPs mechanistic aspects of the chiral recognition process are discussed with respect to the structures of the analytes.
• Thermodynamic parameters were calculated at constant mobile phase compositions in the temperature range 10–50 °C.
• Both enthalpically- and entropically-controlled chiral separations were observed.

High-performance liquid chromatographic methods were developed for the separation of enantiomers of four unnatural paclitaxel precursor phenylisoserine analogs on chiral stationary phases containing macrocyclic glycopeptides and cyclofructans as chiral selectors. The effects of the mobile phase composition, the nature and concentration of different mobile phase additives (alcohols, amines and acids) in different chromatographic modes, temperature and the structures of the analytes on the separations were investigated. Separations were carried out at constant mobile phase compositions in the temperature range 10–50 °C on macrocyclic antibiotic-based and 5–35 °C on cyclofructan-based columns and the changes in enthalpy, Δ(ΔH°), entropy, Δ(ΔS°), and free energy, Δ(ΔG°), were calculated. The elution sequence was determined in most cases; no general rule could be observed.

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