Synthesis and herbicidal activities of novel uracil derivatives containing pyrimidinyl moiety

In order to find novel protoporphyrinogen oxidase inhibitors with high efficacy, broad-spectrum activity, and safety to crops, nine title compounds(4a–4i) were designed and synthesized by introducing pyrimidine moiety into the uracil skeleton with commercially herbicide butafenacil as the lead compound. Their structures were confirmed by 1H NMR, IR, mass spectroscopy and elemental analysis. The bioassay results indicate that most of compounds 4 tested exhibit good to excellent herbicidal activities against B. campestris, A. retroflexus, E. crusgalli and D. sanguinalis in pre-emergence treatment at a dose of 1.5 kg/ha(1 ha=104 m2), for example, compound 4i showed 100% inhibition against the four plants tested in pre-emergence treatment at a dose of 1.5 kg/ha. So, this type of skeleton can be used as a valuable lead compound for the further development of a pre-emergent herbicide.