Jichun Yang

Synthesis and Biological Activity of New (E)-α-(Methoxyimino)benzeneacetate Derivatives Containing a Substituted Pyrazole Ring†

Strobilurins are one of the most important classes of agricultural fungicides. To discover new strobilurin analogues with high activity, a series of new strobilurin derivatives containing a substituted pyrazole in the side chain were synthesized and their biological activities were tested. The compounds were identified by (1)H nuclear magnetic resonance, infrared, and elemental analysis. The test results indicated that the compounds exhibited strong fungicidal activities against Pyricularia oryzae , Phytophthora infestans , Pseudoperonospora cubensis , and Erysiphe graminis . The relationship between structure and biological activity is discussed in terms of the effects of the substituents on the pyrazole ring. The present work demonstrates that strobilurin analogues with a 3-(substituted phenyl)-1H-pyrazol-5-oxy side chain can be used as possible lead compounds for the development of potential agrochemicals.

Design, synthesis and insecticidal evaluation of aryloxy dihalopropene derivatives

Plutella xylostella (P. xylostella) is a highly migratory, cosmopolitan species and one of the most important pest of cruciferous crops worldwide. Pyridalyl as a novel class of insecticides has good efficacy against P. xylostella. On the basis of the commercial insecticide pyridalyl, a series of new aryloxy dihalopropene derivatives were designed and synthesized by using Intermediate Derivatization Methods. Their chemical structures were confirmed by (1)H NMR, high-resolution mass spectrum (HRMS), and single-crystal X-ray diffraction analysis. The insecticidal activities of the new compounds against P. xylostella were evaluated. The results of bioassays indicated that most of the compounds showed moderate to high activities at the tested concentration, especially compounds 10e and 10g displayed more than 75% insecticidal activity against P. xylostella at 6.25mg/L, while pyridalyl showed 50% insecticidal activity at the same concentration. The field trials result of the insecticidal activities showed that compound 10e as a 10% emulsifiable concentrate (EC) was effective in the control of P. xylostella at 75-150g a.i./ha, and the mortality of P. xylostella for treatment with compound 10e at 75g a.i./ha was equivalent to pyridalyl at 105g a.i./ha.

Design, synthesis, and herbicidal activity of novel quaternary ammonium salt derivatives

A series of novel quaternary ammonium salt derivatives were designed and synthesized by introducing the herbicide carboxylic acid into substituted aminoacetanilide compounds which derived from herbicides alachlor or acetochlor, using the intermediate derivatization methods in an attempt to obtain novel candidates for weed control. The herbicidal activity assays in greenhouse demonstrated that some of the title compounds exhibited good herbicidal activities against velvet leaf, youth-and-old age, barnyard grass, and foxtail. Especially, III9 gave the best activity (EC50 (ga.i/ha): YOA 34.1, VEL 33.6, FOX 15.9, BYG 36.2). The field trials indicated that III9 had better herbicidal activity than the commercial herbicide imazethapyr to control broadleaf weeds at 150ga.i/ha. The present work demonstrated that the quaternary ammonium salt derivatives can be used as potential lead compounds for discovering novel herbicides with improved activity. III9 itself is worthy of being further developed as an herbicidal candidate. Further syntheses, structure optimization studies, and field trials around III9 are in progress.