Synthesis of pyridopyrimidone derivatives and their activity against P. falciparum in vitro.

Pyridopyrimidone derivatives 4a-d and 5a- were synthesized as potential antimalarial agents on the basis of the pharmacological properties of existing quinolone analogues such as ciprofloxacine IC50 39.8 microM. Meanwhile among these new compounds, only the 3-amino-7-methyl-1(H)pyrazolo[3,4-b]-pyrido [1,2: 1'2']pyrimido-4-ona 4b, produces significant antimalarial activity IC50 0.42 microM against P. falciparum in vitro. The remaining compounds were effective as antimalarial agents leading from IC50 1.0 microM to IC50 4.47 microM.