Herbicides

A herbicidal compound of the formula:

• ##STR8## or salts thereof, where:
• A is --CH.dbd.;
• R.sup.1 is C.sub.1-6 alkyl, C.sub.1-6 alkoxy, halo or --NR.sup.7 R.sup.8 ;
• R.sup.2 is C.sub.1-6 alkyl or C.sub.1-6 alkoxy;
• R.sup.3 is hydrogen, C.sub.2-6 alkenyl or C.sub.2-6 alkynyl, or alkyl, alkanoyl or alkoxycarbonyl in which the alkyl moiety is of 1 to 6 carbon atoms, and is either unsubstituted or substituted by one or more halogen atoms or alkoxy groups of 1 to 4 carbon atoms;
• R.sup.4 is hydrogen or C.sub.1-6 alkyl which is either unsubstituted or substituted by one or more halogen atoms or alkoxy groups of 1 to 4 carbon atoms;
• R.sup.5 is halo or C.sub.1-6 alkyl which is either unsubstituted or substituted by one or more halogen atoms or alkoxy groups of 1 to 4 carbon atoms or phenyl which is either unsubstituted or substituted by one or more halogen atoms, nitro groups, amino groups, alkylamino, dialkylamino or acylamino groups (in which the alkyl moieties are each of 1 to 4 carbon atoms), cyano groups, or alkyl or alkoxy groups of 1 to 4 carbon atoms;
• and;
• X is --CO.sub.2 R.sup.6, --CONR.sup.7 R.sup.8 or --CN;
• in which R.sup.6, R.sup.7 and R.sup.8, which may be the same or different, each represent hydrogen, C.sub.1-6 alkyl which is either unsubstituted or substituted by one or more halogen atoms or alkoxy groups of 1 to 4 carbon atoms, or one of R.sup.7 and R.sup.8 represents alkylamino, dialkylamino or acylamino groups (in which the alkyl moieties are each of 1 to 4 carbon atoms);
• with the proviso that one or both of the following is true:
• (a) R.sup.5 represents isopropyl and (b) X represents methoxycarbonyl.