Chiroptical properties of some monoazapentahelicenes

The successful separation by HPLC methods of the enantiomers of 4-, 5-, and 6- monoazahelicenes (H4, H5 and H6) on the subsequent circular dichroism measurements is reported. The findings indicate that the circular dichroism spectra were analyzed as a function of time and different rate constants were found in the kinetics of racemization for the three molecules.