Investigation of Novel Pesticides with Insecticidal and Antifungal Activities: Design, Synthesis and SAR Studies of Benzoylpyrimidinylurea Derivatives

Abstract

In order to find pesticides with insecticidal and antifungal activities, a series of novel benzoyl pyrimidinylurea derivatives were designed and synthesized. All target compounds were identified by 1H-NMR spectroscopy and HRMS. Insecticidal and antifungal activity of these compounds were evaluated and the structure-activity relationships (SAR) were clearly and comprehensively illustrated. Compound 7, with low toxicity to zebrafish (LC50 = 378.387 µg mL−1) showed 100% inhibition against mosquito (Culex pipiens pallens) at 0.25 µg mL−1. Both compounds 19 and 25 exhibited broad-spectrum fungicidal activity (>50% inhibitory activities against 13 phytopathogenic fungi), which were better than those of the commercial pesticide pyrimethanil (>50% inhibitory activities against eight phytopathogenic fungi). Furthermore, compounds 19 and 25 exhibited protective activity against Sclerotinia sclerotiorum on leaves of Brassica oleracea L. during in vivo experiments.

Dehydrozingerone Inspired Discovery of Potential Broad-Spectrum Fungicidal Agents as Ergosterol Biosynthesis Inhibitors

“…Azoxystrobin (Yuanye, Shanghai, China) was used as a positive control. After 5 days, the disease was observed and graded . The grading standards were as follows: Grade 0, without disease spot. Grade 1, 3 diseased spots in one leaf. Grade 3, 4–6 diseased spots in one leaf. Grade 5, 7–10 diseased spots in one leaf. Grade 7, 11–20 diseased spots in one leaf, parts are densely packed. Grade 9, single leaf stick spot dense leaf area of more than a quarter. …”

“…After 5 days, the disease was observed and graded. 21 The grading standards were as follows: Grade 0, without disease spot. Grade 1, 3 diseased spots in one leaf.…”