[Objective] In order to improve the herbicidal activity of toxins III（methyl2-methyl-3,5-dinitrobenzoate） from Phoma herbarbum, its structure was optimized by derivatization. [Method] Sixteen novel title compounds were synthesized by nitration and acylation with o-toluic acid as a starting material. Their structures were confirmed by IR and1 H NMR. [Result] The herbicidal activity screening showed that the inhibition rate of J-L-59 against E. crusgalli roots was 93.7% at 100 μg/ml. The fresh weight efficacy of J-L-59 against A. theophrasti and A. retroflexus was 100%at 1 000 g a.i./hm^2 , and the ED50 value for A. retroflexus was 94.06 g a.i./hm^2 .[Conclusion] J-L-59 has higher herbicidal activity.
