Synthesis, antibacterial activity and mechanism of new butenolides derivatives containing an amide moiety.

A series of novel butenolide derivatives containing an amide were designed and synthesized with flupyradifurone as the lead compound. The biological activities test found that this series of compounds did not exhibit insecticidal activity, but had good antibacterial activities. Among all target compounds, compound 19 showed good antibacterial activity in vitro against Xanthomonas oryzae pv. oryzae (Xoo), with an EC50 value of 35.8 mg/L, which was superior to that of bismerthiazol (73.5 mg/L). Under greenhouse conditions, the curative and protective activities of compound 19 against bacterial leaf blight were 40.9% and 48.9% at 100 mg/L, respectively, which were superior to those of bismerthiazol (31.2% and 31.4%). In addition, compound 19 can not only cause changes in the cell surface morphology of Xoo, but also increase the activity of rice defense enzymes. The mechanism of action studies showed that the protective activity of compound 19 against rice bacterial leaf blight is closely related to the improvement of defense-related enzyme activities and the upregulation of proteins involved in oxidative phosphorylation.