Kinetic analysis of the hydroxyl mechanism of the antimalarial effect of fluorinated artemisinin derivatives
Evgenii T Denisov, T. G. Denisova · Kinetics and Catalysis · 2015
Kinetic schemes of intramolecular oxidation are constructed for 13 derivatives of 10-dihydroartemisinin containing fluorine substituents (F and CF3). Each step of the kinetic scheme is characterized by its enthalpy. The activation energy and rate constant of each step are calculated using the intersecting parabolas model. The competition between mono- and bimolecular radical reactions is taken into account. In the case of H abstraction from the α-hydroperoxy-C-H bond, the fragmentation of the molecule with the formation of hydroxyl radicals concerted with the abstraction is taken into account. The antimalarial efficiency of each drug due to the hydroxyl radicals only is calculated from the empirical dependence of the antimalarial activity IC50 on the number of hydroxyl radicals n OH generated by the compound. The compounds whose antimalarial activity is additionally caused by other factors are revealed.