Antimalarial activities of 2,4-diamino-6-[(4-chlorobenzyl)-N-methyl-amino] quinazoline and its salts

We synthesized 2,4-diamino- 6-[(4-chlorobenzyl )-N-methylamino]quinazoline (Am-2159) and its salts. Tests were conducted for their activities against both rodent and simian malarial parasites. Am-2159 and its salts showed prophylactic action on Plasmodium yoelii infection in mice (Table 1), yet their effect lasted for <15 d, because they failed to protect the mice while challenged with the sporozoites 15 d after medication. Am-2159 and its hydrochloride (Am-2160) suppressed P. berghei infection in mice, the ED50 of Am-2160 against both normal and chloro-quineresistant strains of P. berghei being 8.7±2.2 and 4.1±1.0 mg/kg×3 d, respectively. Am-2160 showed neither prophylactic activities (2.5 mg/kg×8 or×5 d) nor curative effect (1.25 mg/kg×5 d) when administered ig to rhesus monkeys infected with the sporozoites of P. cynomolgi. Its toxicity deserved further test.