The present invention relates to 2,4-diamino-6-ethylpyrimidine derivatives that are inhibitors of wild type and quadruple mutant dihydrofolate reductase (DHFR) of Plasmodium falciparum. They also show in vitro antimalarial activities against Plasmodium falciparum for both wild type and mutant that are comparable to or better than pyrimethamine. In addition, the compounds of the present invention show a good selectivity to Plasmodium falciparum and exhibit lower cytotoxicity than pyrimethamine.
