Compounds of the formula wherein A is specified nitrogen-containing heterocycle; R is H2 halogen, CH3, OCH3 or OC2H5; R1 is C1-C3 alkyl, allyl or propargyl: R2 is X1R8 or OH; X1 is O or S; and R8 is an organic group; and their agriculturally suitable salts, exhibit herbicidal activity, especially for the selective control of weeds in rice. The compound may be made by a variety of synthetic routes, e.g. by reacting a haloheterocycle of formula A-Hal with an alkali metal salt of the appropriate 4-hydroxy-benzeneacetate ester.