Novel 4(3H)‐Quinazolinone Derivatives Containing an Isoxazole Moiety: Design, Synthesis, and Bioactivity Evaluation

Abstract

The aim of the present study is to design and synthesize a series of novel 4(3H)‐quinazolinone derivatives containing an isoxazole moiety and evaluate their antifungal activity against Gibberella zeae (G. zeae), Fusarium oxysporum (F. oxysporum), Cytospora mandshurica (C. mandshurica), Phytophthora infestans (P. infestans), and Pellicularia sasakii (P. sasakii), and their antibacterial activity against Ralstonia solanacearum (R. solanacearum) and Xanthomomu oryzae pv. oryzae (Xoo). Bioassay results showed that the target compounds 8a–8o had certain antifungal activities against the test fungus at the concentration of 50 μg/mL, which were lower than those of Hymexazol and Epoxiconazole. Meanwhile, preliminary bioassay results showed that compounds 8a–8o had better antibacterial activity against R. solanacearum and Xoo at 200 and 100 μg/mL. In particular, compound 8i exhibited significant antibacterial activity against Xoo in vitro, with an inhibition rate of 100% at 200 μg/mL, which was superior to those of Bismerthiazol (72%) and Thiodiazole copper (35%).