Antimalarial agent 19 (compound 6e) is an antimalarial active agent. Antimalarial agent 19 has antimalarial activity for the blood stage of P. falciparum K1 and P. berghei with EC 50 values of 0.3 µM, 15.3 µM, respectively. Antimalarial agent 19 has good aqueous solubility, intestinal permeability and microsomal stability compared to gamhepathiopine.