Novel Ferulic Amide Ac6c Derivatives: Design, Synthesis, and Their Antipest Activity

Abstract

Thirty-eight novel ferulic amide 1-aminocyclohexane carboxylic acid (Ac6c) derivatives <b>D1</b>-<b>D19</b> and <b>E1</b>-<b>E19</b> were designed and synthesized, and their antibacterial, antifungal, and insecticidal activities were tested. Most of the synthesized compounds displayed excellent activity against<i>Xanthomonas oryzae</i> pv. <i>oryzae</i> (<i>Xoo</i>), with EC₅₀ values ranging from 11.6 to 83.1 μg/mL better than that of commercial bismerthiazol (BMT, EC₅₀ = 84.3 μg/mL), as well as much better performance compared to that of thiediazole copper (TDC, EC₅₀ = 137.8 μg/mL). <b>D6</b> (EC₅₀ = 17.3 μg/mL), <b>D19</b> (EC₅₀ = 29.4 μg/mL), <b>E3</b> (EC₅₀ = 29.7 μg/mL), <b>E9</b> (EC₅₀ = 27.0 μg/mL), <b>E10</b> (EC₅₀ = 18.6 μg/mL), and <b>E18</b> (EC₅₀ = 20.8 μg/mL) showed much higher activity on <i>Xanthomonas oryzae</i> pv. <i>oryzicola</i> compared with BMT (EC₅₀ = 80.1 μg/mL) and TDC (EC₅₀ = 124.7 μg/mL). In relation to controlling the fungus, <i>Rhizoctonia solani</i>, <b>E1</b>, <b>E10</b>, and <b>E13</b> had much lower EC₅₀ values of 0.005, 0.140, and 0.159 μg/mL compared to hymexazol at 74.8 μg/mL. Further <i>in vivo</i> experiments demonstrated that <b>E6</b> and <b>E12</b> controlled rice bacterial leaf blight disease better than BMT and TDC did. Scanning electron microscopy (SEM) studies revealed that <b>E12</b> induced the <i>Xoo</i> cell membrane collapse. Moreover, <b>D13</b> (73.7%), <b>E5</b> (80.6%), and <b>E10</b> (73.4%) also showed moderate activity against <i>Plutella xylostella</i>. These results indicated that the synthesized ferulic amide Ac6c derivatives showed promise as candidates for treating crop diseases.