Josozaioyobisonoseiho

摘要

Pyridazine derivatives of the formula: IMAGE wherein R1 represents a fluorine, chlorine, bromine or iodine atom or an alkyl, alkoxy, alkylthio, alkylsulphonyl, nitro, trifluoromethyl, cyano, alkoxycarbonyl, carboxy, aminocarbonyl, amino, monoalkylamino or dialkylamino group, R2 represents a hydrogen atom or an alkyl group, R3 represents a hydrogen, fluorine, chlorine or bromine atom or an alkyl, methoxy, ethoxy or hydroxy group, or R2 and R3 together represent an oxygen atom or a hydroxyimino group, R4 represents a hydrogen atom or an alkyl group and n represents zero or an integer from 1 to 5 inclusive, are new compounds useful as herbicides.