[Synthesis and biological activities of 2,4-diamino-5-chloro-6-substituted quinazolines].

Title compounds were synthesized by condensation of 5-chloro-2,4,6-triaminoquinazoline (8) with various substituted benzaldehydes to produce the corresponding Schiff bases, followed by reduction with NaBH4, II and III were obtained by formylation or nitrosation of I respectively. Primary screening for suppressive therapeutic effects against P. berghei in mice showed that eight of the twelve compounds produced 100% suppression when administered orally at dose of 20 mg/kg. The results against L1210 Leukemia cell and B16 melanoma cell in vitro exhibited potent inhibition. Among them four compounds were more active than MTX and SIPI 759. Further work is in process. Antibacterial tests in vitro showed that a number of compounds possessed moderate activities against Diplococcus pneumoniae.