Synthesis and biological evaluation of new imidazo[1,2-a]pyridine derivatives designed as mefloquine analogues

This paper describes the synthesis and the in vitro antimalarial profile of two new imidazo[1,2-a]pyridine derivatives 4HCl and 13HCl, structurally proposed as mefloquine (1) analogues, by exploring bioisosterism and molecular simplification tools. The synthetic route employed to access the title compounds used, as starting material, the previously described ethyl 2-methylimidazo[1,2-aJpyridine-3-carboxylate derivative (5). These novel heterocyclic derivatives 4HCl and 13HCl presented modest antimalarial activity against the W-2 and D-6 clones of Plasmodium falciparum as well as inhibitors of in vitro heme polymerization compared to mefloquine.