Abstract
Comparative examinations were made on the activities against Piricularia oryzae using the halogen-substituted phenylpyrazolones, halogen-substituted β-acetylphenylhydrazines, and halogen-substituted phenylhydrazines synthesized in earlier work. The activities decreased in the order of hydrazines, acetylhydrazines, and pyrazolones. Assuming that the activity is due to the[chemical formula]skeleton, a series of compounds having this skeleton were synthesized, a total of over 200 compounds classified into 14 groups, and relationship between their structure and activity against rice blast has been discussed.
