Аннотация:A combined strategy utilizing circular dichroism (CD), IR, NMR experimental techniques, and the DFT study of bio-active ferrocene-containing betulins was applied to investigate their physicochemical and chiroptical properties. A hybrid of the betulin backbone with the ferrocene moiety combined through a piperazine linker was prepared in good yield from readily avaible ferrocene carboxylic acid and betulonic acid, a natural betulin derivative. The analytical characterization of initial compounds and betulin-ferrocene hybrid was carried out by the CD method, IR, 1H and 13C spectroscopy. CD and IR spectra of betulonic acid and the target compound were simulated using DFT calculations. A high correlation between experimental data and DFT calculation results was obtained. It is noteworthy that in the visible region of the CD spectrum of the betulin-ferrocene hybrid, a significant positive maximum of the Cotton effect is observed in the region of 460 nm, which is responsible for the pharmacophore ferrocene fragment located in the chiral environment of the betulin framework, taking into account its configurational effects. The theoretically calculated energies of the HOMO-LUMO orbitals and electronic characteristics including electronegativity, electrophilicity index, dipole moment, as well as isotropic and anisotropic polarizabilities for the optimized structures of betulin, betulonic acid and piperazine-linked ferrocenyl betulonic acid were determined by the DFT/B3LYP method.
