| abstract |
Novel compounds are provided of the general formula <CHEM> wherein R<1> represents a hydrogen atom, an optionally substituted cycloalkyl group having 3 to 5 ring carbon atoms and a total of 3 to 6 carbon atoms, or an alkyl group having 1 to 4 carbon atoms or an alkenyl group having 2 or 3 carbon atoms which groups may be unsubstituted or substituted by one or more fluorine, chlorine and/or bromine atoms; R<2> represents a fluorine, chlorine or bromine atom, a trifluoromethyl, nitro or cyano group, or an alkyl, alkoxy or alkylthio group having from 1 to 6 carbon atoms; and A represents various optionally-substituted 5-membered heterocycles containing up to 3 nitrogen atoms and also in some cases an oxygen atom. These compounds have herbicidal activity. |