Herbicides

摘要

Pyrido[2,3-d]pyridazin-5-one and pyrido[2,3-d]pyridazin-5-thione derivatives of general formula (I): wherein R and R<1> independently represent hydrogen, optionally halogenated alkyl, alkenyl or alkynyl, optionally substituted heterocycle or a group -[CR<4><1>R<4><2>]n-(phenyl)-(R<3>)q; R<2> represents halogen, optionally halogenated alkyl, alkenyl or alkynyl, CN; -CO2R<4>; -S(O)rR<4>; -NO2; -NR<4><1>R<4><2>; -OH; -COR<4>, -S(O)rR<5>, -CO2R<5>, -OR<5>; -CONR<4><1>R<4><2>, -OSO2R<5>, -OSO2R<6>, -OCH2R<5>, -N(R<4><1>)COR<6>, -N(R<4><1>)SO2R<5>, -N(R<4><1>)SO2R<6>, -SO2NR<4><1>R<4><2>,optionally substituted phenyl, alkoxy or haloalkoxy; X represents oxygen or sulphur; R<3> represents halogen, optionally halogenated alkyl, alkenyl, alkoxy, alkynyl, -OH, -S(O)rR<4>, -CO2R<4>, COR<4>, -CN, -NO2, -NR<4><1>R<4><2>, -OR<5>; -CONR<4><1>R<4><2>, -OSO2R<5>, -OSO2R<6>, -OCH2R<5>, -N(R<4><1>)COR<6>, -N(R<4><1>)SO2R<5>, -N(R<4><1>)SO2R<6> or -SO2NR<4><1>R<4><2>; R<4> represents a hydrogen atom or optionally halogenated C1-6 alkyl; R<4><1> and R<4><2>, which may be the same or different, each represents a hydrogen atom or optionally halogenated C1-4alkyl; R<5> represents a phenyl group optionally substituted by from one to five groups selected from halogen, nitro, cyano, R<4> and -OR<4>; m represents zero or an integer from one to three; n represents zero, one or two; where n is two, the groups -(CR<4><1>R<4><2>)- may be the same or different; q represents zero or an integer from one to five; r represents zero, one or two; with the proviso that when m represents zero R and R<1> do not simultaneously represent hydrogen; and agriculturally acceptable salts thereof are useful as herbicides.