Synthesis and fungicidal activity of novel imidazo[4, 5-b]pyridine derivatives

A series of novel imidazo[4,5-b]pyridine derivatives were synthesized and their structures were characterized by NMR spectroscopy, mass spectrometry and elemental analysis. The results of bioassays showed that some compounds exhibit good fungicidal activity against Puccinia polysora In particular, compound 7b showed an EC50 value of 4.00 mg/L, which was comparable with that of tebuconazole. Besides, preliminary structure-activity relationship was discussed.