Quantum chemical analysis of alternative pathways for iron activation step for artemisinin, a new antimalarial drug.

Malaria is a mosquito-borne parasitic infection. It can be said that malaria is a very important tropical mosquito-borne infectious disease. The selection of antimalarial drugs depends on the species and the reported resistance pattern in each setting. Artemisinins are a new group of antimalarial drugs against the drug-resistant strains of malarial parasites. The mechanism of action of artemisinin compounds consists of two important steps: (a) activation and (b) alkylation. In the activation step by iron, there are two possible pathways for developing C-4 free radical: (a) 1.5 H-shift and (b) C-C cleavage. Here, the author performs a quantum chemical analysis of the activation reaction of artemisinin by the two alternative pathways. According to this study, the required energy for compound formation in C-C cleavage is more than that for C-O cleavage. It can be noted that the C-C cleavage pathway is less preferable, implying that the 1.5 H-shift should be the more common phenomenon.