HETEROCYCLIC COMPOUNDS

"Heterocyclic Compounds" A herbicidal compound of formula (I) : (I) or N-oxide or quaternised derivative thereof; 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 system; W is O or NR1 where R1 is H or lower alkyl; A, B, D are independently selected from N, NR2, N-E, CR6, C-E or C(R6)E; wherein E is: provided 2 of A, B and D are N, NR2 or N-E and at least one of A, B or D carries a group E; where R2 is H, OR7, CN, COOR8, alkyl or haloalkyl; R3 and R4 are independently selected from H, optionally substituted alkyl, alkenyl or alkynyl, halogen, NR9R10, or R3 and R4 together with the carbon to which they are attached form an optionally substituted alkenyl or cycloalkyl group; R5 is C02R11, CN, COR11, CH20R11, CH(OH)R11, CH(OR11)R12, CSNH2, COSR11, CSOR11, CONHSO2R11, CONR13R14, CONHNR13R14, CONHN+R13R14R15 Y-, CO2-M+ or COON=CR13R14; X is (CH2)n, CH=CH, CH(OR16)CH2 or COCH2; where n is 0, 1 or 2; M+ is an agriculturally acceptable cation; Y- is an agriculturally acceptable anion; R6 is H, halogen, OR7, CN, COOR8, alkyl or haloalkyl; R7 and R8 are independently H or lower alkyl; R11, R12 and R16 are independently selected from H or an optionally substituted alkyl, alkenyl, alkynyl or aryl group; and R9, R10, R11, R14 and R15 are independently selected from H or an optionally suhstituted alkyl, alkenyl, alkynyl or aryl group or any two of R9, R10, R13, R14 and R15 together with the atom to which they are attached form a cycloalkyl or heterocyclic ring providing that the compound is other than 5-(2,4-dichlorophenoxy)indazol-1-ylacetic acid or its methyl ester. Procsss for the preparation of these compounds and compositions containing them are also described.