High-performance liquid chromatographic separation of enantiomers and diastereomers of 2-methylcyclohexanone thiosemicarbazone, and determination of absolute configuration and configurational stability

Simultaneous HPLC diastereo- and enantioseparations of 2-methylcyclohexanone thiosemicarbazone (2-MCET) were accomplished on coated- and immobilized type polysaccharide-based chiral stationary phases (CSPs). The identification of all stereoisomeric forms and their stereochemistry were achieved by combining theoretical, HPLC and chiroptical data. The stereochemical stability of the target compound was studied by classical off-column and dynamic HPLC kinetic procedures and the influence of different parameters such solvent, TFA concentration and temperature on stereoisomerization process was evaluated. The findings obtained by chromatographic and kinetic experiments were used to develop a simple method to convert the racemic form of 2-MCET into a single enantiomer.