2-Aryl-3H-indol-3-ones: Synthesis, electrochemical behaviour and antiplasmodial activities

Abstract The synthesis of indolone derivatives and their antiplasmodial activity in vitro against Plasmodium falciparum at the blood stage are described. The 2-aryl-3 H -indol-3-ones were synthesized via deoxygenation of indolone- N -oxides. Electrochemical behaviour, antiplasmodial activity and cytotoxicity on human tumor cell lines were compared to those of indolone- N -oxides. The antiplasmodial IC 50 (concentrations at 50% inhibition) of these compounds ranged between 49 and 1327 nM. Among them, the 2-(4-dimethylaminophenyl)-5-methoxy-indol-3-one, 7 , had the best antiplasmodial activity in vitro (IC 50  = 49 nM; FcB1 strain) and selectivity index (SI (CC 50 MCF7/IC 50 FcB1) = 423.4). Thus, the hits identified in this deoxygenated series correspond to their structural homologs in the N -oxide series with comparable electrochemical behaviour at the nitrogen–carbon double bond.