Synthesis and fungicidal activity of 1,3,4-oxadiazol-2-yl thioether derivatives containing a phenazine-1-carboxylic acid scaffold.

To find new higher fungicidal activities lead compounds and develop new eco-friendly agrochemicals, natural product phenazine-1-carboxylic acid (PCA) as scaffold, a series of 1,3,4-oxadiazol-2-yl thioether derivatives was synthesized and bio-assayed. The results reveal that most target compounds possessed moderate to good fungicidal activities against R. solani, S. sclerotioru and P. oryzac Cavgra. Compounds 6n and 6o exhibit more than 90% bioactivity against S. sclerotioru. The EC50 value of compounds 6n and 6o are 11.16 and 30.47 μM respectively, in particular, compound 6n show equal activity against S. sclerotioru to PCA (10.49 μM). This result provides a valuable lead compound for further studies.