A series of novel N-[2-(4,6-dimethoxypyrimidin-2-yloxy)benzylidene]-2-aryloxyacetohydrazides 3 was synthesized by the condensation reactions of 2-(4,6-dimethoxypyrimidin-2-yloxy)benzaldehyde 1 with various 2-aryloxyacetohydrazides 2.Their structures were characterized by IR,1H NMR,EI-MS,ESI-MS and elemental analysis.The results of bioassay(in vivo) indicated that most of the title compounds 3 possessed good herbicidal activities against Amaranthus retroflexus in both pre-emergence and post-emergence treatme...