Discovery of Antimalarial Azetidine-2-carbonitriles That Inhibit P. falciparum Dihydroorotate Dehydrogenase.

Dihydroorotate dehydrogenase (DHODH) is an enzyme necessary for pyrimidine biosynthesis in protozoan parasites of the genus , the causative agents of malaria. We recently reported the identification of novel compounds derived from diversity-oriented synthesis with activity in multiple stages of the malaria parasite life cycle. Here, we report the optimization of a potent series of antimalarial inhibitors consisting of azetidine-2-carbonitriles, which we had previously shown to target DHODH in a biochemical assay. Optimized compound BRD9185 () has activity against multidrug-resistant blood-stage parasites (EC = 0.016 μM) and is curative after just three doses in a mouse model. BRD9185 has a long half-life (15 h) and low clearance in mice and represents a new structural class of DHODH inhibitors with potential as antimalarial drugs.