Synthesis of Novel 3-Chloropyridin-2-yl-Pyrazole Derivatives and their Insecticidal, Fungicidal Activities and QSAR Study

In our early study, a series of anthranilic diamides containing acylthiourea linker (C) was reported to display favorable activities. Based on that research, four series of novel pyridylpyrazole derivatives (D-G) derived from C were designed and synthesized. Totally 24 compounds were synthesized and all the compounds were characterized by melting points, H-1 NMR, C-13 NMR and HRMS. Bioassay results indicated that compounds 5b, 5c and 6b showed 100 % insecticidal activities against oriental armyworm (Mythimna separata) at 200mg/L. Their fungicidal activities against A. solani, F. graminearum, P. capsici, S. sclerotiorum, B. cinerea and R. solani were evaluated and the results indicated that compounds 7a-g which contained acylguanidine linker showed favourable antibacterial activity against B. cinerea, among which 7d and 7f showed 97.5 % inhibitory activities against B. cinerea at 50mg/L. To further explore the comprehensive structure-activity relationship on the basis of insecticidal activity data, comparative molecular field analysis (CoMFA) was performed, and a statistically reliable model with good predictive power (r(2) = 0.972, q(2) = 0.604) was achieved.