Design, Synthesis and Biological Activity of Novel (3-Substituted phenyl-2-propen-1-ylidene)-benzoylhydrazones

To find new lead compound with high fungicidal activity, a series of novel (3-substituted phenyl-2-propen-1-ylidene)-benzoylhydrazones were designed via the method of linking active sub-structures which were cinnamaldehyde and benzoylhydrazine. The target compounds were synthesized from substituted benzoic acid in three steps. Their structures were confirmed by H-1 NMR, IR spectra and elemental analysis. The in vitro bioassay results indicated that some target compounds showed obvious inhibitory activities against mushroom tyrosinase compared with lead cinnamaldehyde. Besides, some target compounds exhibit certain fungicidal activity against Fusarium graminearum, Botrytis cinerea and Colletotrichum lagenarium. Compound 5r exhibited equivalent fungicidal activities to polyoxin B at a concentration of 100 mu g/mL. The preliminary structure-activity relationship was also analyzed for further optimization.