Synthesis and Antibacterial Activities of Novel Quinazoline-2,4-dione Derivatives Containing the 1,2,4-Triazole Schiff-Base Unit

Eighteen novel quinazoline-2,4-dione derivatives containing the 1,2,4-triazole Schiff-base unit were designed and synthesized, based on the connection method of active fragments. Their structures were characterized by H-1 NMR, C-13 NMR, MS, IR and elemental analysis. The preliminary antibacterial test indicated that all the target compounds possessed an excellent inhibition activity (>= 93%) against Xanthomonas oryzae pv. oryzae (Xoo) at the concentration of 200 mu g/mL, which was obviously better than those of control agents thiodiazole-copper and bismerthiazol. Compounds 7a, 7c similar to 7g and 7j similar to 7l still displayed 100% inhibition rate against Xoo even at the concentration of 100 mu g/mL. Moreover, all the target compounds exhibited a certain inhibition activity against Xanthomonas axonopodis pv. citri, but no inhibition activity against Ralstonia solanacearum.