Synthesis, Crystal Structure, and Antifungal Activity of Quinazolinone Derivatives

In this paper, four new compounds with quinazolinone structure were designed and synthesized based on the special biological activity of quinazolinone. The four new compounds containing quinazolinone structures were synthesized using a one-pot method after intramolecular cyclization and dehydration catalyzed by aqueous methylamine solution. Their structures were characterized using H-1 NMR, C-13 NMR, FT-IR, and HRMS, and the crystal structure of 2a was characterized using X-ray diffraction. In their potential antifungal activity tests, it was found that the four newly synthesized compounds exhibited significant antifungal activity against all seven phytopathogenic fungi at concentrations of 150 and 300 mg/L. Among them, the target compound 2c showed the best inhibitory effect against Fusarium oxysporum f. sp. Niveum fungus, with 62.42% inhibition at a concentration of 300 mg/L. Compound 2c is expected to be a leading compound for the treatment of watermelon Fusarium wilt in the future, which is worth further study.