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, 1H NMR, 13C 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 (r2 = 0.972, q2 = 0.604) was achieved.