HETEROCYCLIC COMPOUNDS

HETEROCYCLIC COMPOUNDS A compound of formula (I) : (I) in which the dotted lines indicate the presence of two double bonds arranged so as to form a fused hetero-aromatic ring system; Ar is an optionally substituted aryl or heterocyclic ring; W is O or NR1, where R1 is hydrogen or lower alkyl; X is (CH2)n, CH=CH, CH(OR5)CH2, COCH2; where n is 0, 1 or 2; R2 and R3 are independently selected from H, optionally substituted alkyl, alkenyl or alkynyl, halogen, NR6R7 or R2 and R3 together with the carbon to which they are attached form an optionally substituted alkenyl or cycloalkyl group; R4 is CO2R8, CN, COR8, CH2OR8, CH(OH)R8, CH(OR8)R9, CSNH2, COSR8, CSOR8, CONHSO2R8, CONR10R11, CONHNR10R11, CONHN+R10R11R12R13-, CO2-R14+ or COON-CR10R11; R14+ is an agriculturally acceptable cation; and R13 is an agriculturally acceptable anion; R5, R8 and R9 are independently selected from H or an optionally substituted alkyl, aryl, alkenyl or alkynyl group; and R6, R7, R10, R11, and R12 are independently selected from H or an optionally substituted alkyl, alkenyl, aryl or alkynyl group or any two of R6, R7, R10, R11 and R12 together with the atom to which they are attached form a cycloalkyl or heterocyclic ring. Compounds of formula (I) are herbicidal and composition containing them and methods of treatment using them are also described.