Search

In an effort to discover a new insecticide, we designed and synthesized a series of novel meta‐diamide compounds containing 1,2,4‐triazole with cyproflanilide as a lead compound. All the compounds were characterized by 1H NMR, 13C NMR, and HR‐MS. Both Plutella xylostella and Mythimna separata were tested for their insecticidal activity at 200 mg/L (P. xylostella: 0%–100%; M. separata: 0%–100%), 20 mg/L (P. xylostella: 0%–97%; M. separata: 0%–100%), and 2 mg/L (P. xylostella: 0%–97%; M. separata: 0%–100%), while Aphis craccivora was tested for its insecticidal activity at 400 mg/L (A. craccivora: 0%–36%). Further studies are needed to investigate the insecticidal activity of A. craccivora. Preliminary bioactivity results showed that most of the compounds had good insecticidal activity at 200 mg/L against P. xylostella and M. separata. Especially, the compound 7p, N‐(cyclopropylmethyl)‐N‐(5‐((2,6‐dibromo‐4‐(perfluoropropan‐2‐yl)phenyl) carbamoyl)‐2‐(1H‐1,2,4‐triazol‐1‐yl)phenyl)‐6‐(trifluoromethyl)nicotinamide (7p), showed good insecticidal activity at even lower doses of 2 mg/L (P. xylostella: 97%; M. separata: 100%), which was equivalent to that of the lead compound cyproflanilide (P. xylostella: 100%; M. separata: 100%), as well as significantly better than the two known compounds Ia (P. xylostella: 97%; M. separata: 0%) and Ib (P. xylostella: 60%; M. separata: 0%). Preliminary structure–activity relationship was also discussed based on insecticidal tests. The results indicate that meta‐diamide compounds containing 1,2,4‐triazole can be developed as novel insecticides. [ABSTRACT FROM AUTHOR]

In searching for novel insecticide lead, 20 new meta-diamide compounds containing triazole were designed and synthesized regarding cyproflanilide as lead compound. All the compounds were characterized by 1 H NMR, 13 C NMR, and High-resolution mass spectra (HR MS). In preliminary bioassay, we found that one of the compounds: N-(cyclopropylmethyl)-N-(5-((2,6-dibromo-4-(1,2,2,2-tetrafluoro-1-(trifluoromethyl)ethyl)phenyl)carbamoyl)-2-(1H-1,2,4-triazol-1-yl)phenyl)-6-(trifluoromethyl) nicotinamide (16a) had high activity against the target organism Plutella xylostella at 1 mg/L and against the target organism Mythimna separata at 2 mg/L. It is obviously superior to the known compounds I a and I b , and it is equivalent to cyproflanilide, and the LC 50 values of the compound against P. xylostella and M. separata were 0.90 mg/L and 0.64 mg/L, respectively. It is providing important clues for subsequent structure-activity relationship (SAR) studies. From this, we explored the SAR of these compounds. Through comprehensive analysis of their structural characteristics and insecticidal activity data, we found that different halogen substituents on benzene ring and different aromatic substituents on amino group in the compound had significant effects on insecticidal activity. This has certain guiding significance for further structural optimization and activity enhancement., (© 2024 Wiley‐VHCA AG, Zurich, Switzerland.)