High-performance liquid chromatographic enantioseparation of Betti base analogs on a newly developed isopropyl carbamate-cyclofructan6-based (IP-CF6) chiral stationary phase

摘要

The direct separation of the enantiomers of 1-(α-aminoarylmethyl)-2-naphthol, 1-(α-aminoalkyl)-2-naphthol, 2-(α-aminoarylmethyl)-1-naphthol analogs and 2-(1-amino-2-methylpropyl)-1-naphthol) was performed on a newly developed chiral stationary phase containing isopropyl carbamate-cyclofructan6 as chiral selector, with n-heptane/alcohol/TFA as mobile phase.The effects of the mobile phase composition, the nature and concentration of the alcoholic and acidic modifiers, and the structures of the analytes on the retention and resolution were investigated. In some cases separations were carried out at constant mobile phase compositions in the temperature range 5-40 °C. Thermodynamic parameters and Tiso values were calculated from plots of ln k’ or ln α versus 1/T. -Δ(ΔH°) ranged from 2.8. to 3.2 kJ mol⁻¹, -Δ(ΔS°) from 7.7 to 10.1 J mol⁻¹ K⁻¹ and -Δ(ΔG°) from 0.2 to 0.5 kJ mol⁻¹. It was found that the enantioseparations were enthalpy driven. The sequence of elution of the stereoisomers determined in some cases was (R)<(S).