The novel compounds of formula I:
 wherein R, A, X1, X2, X3 and Z have the meaning given in claim 1, and the agronomically acceptable salts or N-oxide thereof, and herbicidal compositions containing such compounds as active ingredients.
                            公式I的新化合物:其中R、A、X1、X2、X3和Z的含义如权利要求1所述,并且其农学上可接受的盐或N-氧化物,以及含有这些化合物作为活性成分的
除草剂组合物。