Looking for new antiplasmodial quinazolines: DMAP-catalyzed synthesis of 4-benzyloxy- and 4-aryloxy-2-trichloromethylquinazolines and their in vitro evaluation toward Plasmodium falciparum
Résumé
A DMAP catalyzedsynthesis of new 4-benzyloxy-and 4-aryloxy-2-trichloromethylquinazolines was studied, in a view to react 4-chloroquinazolines with poorly nucleophilic alcohols such as benzylic alcohols, via a simple and cheapS N Ar reaction approach. A fast (1 h) general operating procedure, affording good reaction yields,was achieved under microwave irradiation. Thus, a series of 35 molecules was obtained and evaluated in vitro on the K1 multi-resistant P. falciparum strain, in parallel with a cytotoxicity assessment on the human HepG2 cell line. 5 hit-molecules were identified, presenting both promising antiplasmodial activity (1.5 µM < IC 50 < 2 µM) and low cytotoxicities (25 µM < CC 50 < 45 µM). Apart for 2 molecules, the global series displayed a satisfying solubility in the aqueous biological media. Structure-activity relationships showed that the molecules presenting a benzyloxy moiety were less cytotoxic than the ones bearing a phenoxy moiety at position 4 of the quinazoline ring. It also appeared that the introduction of a heteroaryl moiety afforded inactive compounds. Finally, the most active and selective molecules (Selectivity index = 22-27) were the ones presenting either an unsubstituted benzyloxy group or a phenoxy group, this last bearing a p-bromo or an o-acetyl substituent.
Highlights:► The DMAP-catalyzed S N Ar reactionbetween 4-chloro-2-trichloromethylquinazoline and various alcohols or phenols was studied. ► A series of 35 new quinazolineswas synthesized in good yields. ►In vitroevaluationwas made on Plasmodium falciparum.► 5 selective antiplasmodial hit molecules were identified.
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