Synthesis and herbicidal activity evaluation of novel diacylhydrazine derivatives containing pyrazolyl moiety

In order to discover pesticide lead compounds with high herbicidal activity, 13 novel diacylhydrazine derivatives containing pyrazolyl pharmacophore were designed and synthesized by introducing the pyrazolyl pharmacophore into the diacylhydrazine scaffold. Their structures were confirmed by 1H NMR and HRMS. The herbicidal activity of these compounds was evaluated. The dish test results indicated that the growth inhibition rates of the roots and stems of Triticum aestivum, Brassica campestris, Sorghum bicolor and Cucumi sativus were up to 80% for N'-(2-(2,4-dichlorophenoxy) acetyl)-3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carbohydrazide (6i) at the dosage of 200 mg/L. The pot test results showed that the growth inhibition rate of Amaranthus retroflexus and Eclipta prostrate for compound 6i were 80% by postemergence foliar spray processing at the dose of 150 g/hm2; and compound 6i also demonstrated inhibition rate of 80% against A. retroflexus by preemergence soil spray processing at the same dose.