Synthesis and antibacterial evaluation of novel Schiff base derivatives containing 4(3H)-quinazolinone moiety

A series of novel Schiff base derivatives containing 4(3 H )-quinazolinone moiety were synthesised and their antibacterial activities against tobacco and tomato bacterial wilts evaluated in vitro. Out of the synthesised compounds, 5g , 5j , 5n , 5m and 5p exhibited excellent antibacterial activities against tobacco bacterial wilt, with half maximal effective concentrations (EC 50 ): 160.34, 158.03, 125.94, 148.09 and 133.67 (all in μg mL −1 ), respectively, which were better than the EC 50 of thiodiazole–copper (216.70 μg mL −1 ). Compounds 5j , 5n and 5o also showed good antibacterial activities against tomato bacterial wilt, with EC 50 of 95.20, 90.03 and 83.21 (all in μg mL −1 ) respectively, which were better than the EC 50 of thiodiazole–copper (99.80 μg mL −1 ). These compounds may prove to be useful as potential antibacterial agents.