New amide derivatives of quinoxaline 1,4-di-N-oxide with leishmanicidal and antiplasmodial activities.

Malaria and leishmaniasis are two of the World's most important tropical parasitic diseases. Continuing with our efforts to identify new compounds active against malaria and leishmaniasis, twelve new 1,4-di-N-oxide quinoxaline derivatives were synthesized and evaluated for their in vitro antimalarial and antileishmanial activity against Plasmodium falciparum FCR-3 strain, Leishmania infantum and Leishmania amazonensis. Their toxicity against VERO cells (normal monkey kidney cells) was also assessed. The results obtained indicate that a cyclopentyl derivative had the best antiplasmodial activity (2.9 µM), while a cyclohexyl derivative (2.5 µM) showed the best activity against L. amazonensis, and a 3-chloropropyl derivative (0.7 µM) showed the best results against L. infantum. All these compounds also have a Cl substituent in the R⁷ position.