Pyrido(2,3-d) pyridazin-5-one and pyrido(2,3-d)pyridazin-5-thione derivatives, processes for their preparation and herbicidal compositions containing them

摘要

The invention provides compounds of formula:    wherein R and R¹ independently represent hydrogen, optionally halogenated alkyl alkenyl or alkynyl;-(-CR³R⁴)_n-(optionally subtituted phenyl); -(-CR³R⁴)_nHet; or-(-CR³R⁴)_n-Ar, wherein Ar is an optionally substituted bicycle;   wherein at least one of the groups R and R¹ represents -(-CR³R⁴)_n-Ar;   R² represents R⁵ or optionally substituted phenyl;   X is oxygen or sulphur; m is 0, 1, 2 or 3;   R³ and R⁴, independently represent hydrogen, alkyl or haloalkyl;   R⁵ is halogen, optionally halogenated alkyl, alkenyl or alkynyl;or a group selected from cyano, nitro, -CO₂R⁶, -S(O)_pR⁶, -NR³R⁴, -COR⁶, -S(O)_pR⁷, -CO₂R⁷, -OR⁷, -CONR³R⁴, -OSO₂R⁷, -OSO₂R⁸, -OCH₂R⁷, -N(R³)COR⁸, -N(R³)SO₂R⁸, -N(R³)SO₂R⁷, -SO₂NR³R⁴, -Si(R⁸)₃ and -OR⁶;   n is zero, 1 or 2; q is zero or an integer from 1 to 5;   Het represents an optionally substituted heterocycle;   R⁶ represents hydrogen, alkyl or haloalkyl;   p is zero, one or two; r is one or two;   R⁷ represents optionally substituted phenyl;   R⁸ represents alkyl or haloalkyl;   R⁶¹ and R⁶² independently represent hydrogen, halogen, alkyl or haloalkyl;   and agriculturally acceptable salts thereof;   which possess utility as herbicides.