Synthesis and Bioactivity Evaluation of Novel Arylimines Containing a 3-Aminoethyl-2-[(<i>p</i>-trifluoromethoxy)anilino]-4(3<i>H</i>)-quinazolinone Moiety

Abstract

Twenty-seven novel (E)-3-[2-arylideneaminoethyl]-2-[4-(trifluoromethoxy)anilino]-4(3H)-quinazolinone derivatives were synthesized by reacting various aromatic aldehydes with intermediate 6. The target compounds were characterized by (1)H NMR, (3)C NMR, IR, and elemental analysis. Bioassay results revealed that some of the compounds have strong antifungal activities against six fungi ( Gibberella zeae , Fusarium oxysporum , Clematis mandshurica , Paralepetopsis sasakii , Phytophthora infestans , and Sclerotinia sclerotiorum ) and three bacteria ( Xanthomonas oryzae , tomato bacterial wilt, and tobacco bacterial wilt). Notably, these compounds exhibited the highest activity against tomato bacterial wilt and X. oryzae, with 50% effective concentration (EC50) values ranging from 45.96 to 93.31 μg/mL and from 20.09 to 21.33 μg/mL, respectively, which are superior to those of the commercial antibacterial agents thiodiazole-copper (99.80 μg/mL) and bismerthiazol (92.61 μg/mL). These results indicate that novel arylimine derivatives containing the 4(3H)-quinazolinone moiety can effectively control tobacco bacterial wilt, tomato bacterial wilt, and X. oryzae. Evaluation of their bactericidal properties in field studies as well as the mechanisms underlying their enhanced antibacterial activity should be interesting topics for future investigations.