Fig. 23From: The past, present and future of anti-malarial medicinesKey stages in the hit to lead pathway of ACT-451840. Initial change of the n-pentyl group to an acylpiperazine (A′2) helped to improve the physicochemical properties. Subsequent introduction of a tert-butyl in place of the trifluoromethyl (A′3) and a cyano group on the southern phenyl ring resulted in the optimized compoundBack to article page