HPLC Separaton of Hydrophobic Atropisomers

The separation of racemic-N-[(2Z)-4-methyl-3-(2-methylphenyl)-1,3-thiazol-2(3H)-ylidene]-N- (2-chloro-4-nitrophenyl)amine, which belongs to the 2-aryl-imino-N-(2-aryl)-thiazoline family, to collect its atropisomers, was studied using reversed-phase high-performance liquid chromatography (RP-HPLC) with hydroxypropyl-gamma-cyclodextrin (HP-γ-CD) as a complexing additive to the racemic mixture (to obtain chiral molecules) and hexane-propan-2-ol as a mobile phase. The effects of mobile phase composition, concentration of HP-γ-CD and time of incubation of the CD-substrate on separation were systematically investigated to establish the optimum resolution conditions.