Design, synthesis, and insecticidal activities of propargyloxy-naphthalene-sulfonamide derivatives

Synthetic Modification and Insecticidal Activity of 4-epi-cis-Dihydroagarofuran Derivatives

To synthesize the fundamental framework of dihydroagarofuran, a novel strategy was devised for constructing the C-ring through a dearomatization reaction using 6-methoxy-1-tetralone as the initial substrate. Subsequently, the dihydroagarofuran skeleton was assembled via two consecutive Michael addition reactions. The conjugated diene and trans-dihydroagarofuran skeleton were modified. The insecticidal activities of 33 compounds against Mythimna separata were evaluated. Compounds 11-5 exhibited an LC50 value of 0.378 mg/mL. The activity exhibited a remarkable 29-fold increase compared to positive control Celangulin V, which was widely recognized as the most renowned natural dihydroagarofuran polyol ester insecticidal active compound. Docking experiments between synthetic compounds and target proteins revealed the shared binding sites with Celangulin V. Structure-activity relationship studies indicated that methyl groups at positions C4 and C10 significantly improved insecticidal activity, while ether groups with linear chains displayed enhanced activity; in particular, the allyl ether group demonstrated optimal efficacy. Furthermore, a three-dimensional quantitative structure-activity relationship model was established to investigate the correlation between the skeletal structure and activity. These research findings provide valuable insights for discovering and developing dihydroagarofuran-like compounds.

Synthesis, and Insecticidal Activities of Propargyloxy-Diphenyl Oxide-Sulfonamide Derivatives

Agricultural pests are the primary contributing factor to crop yield reduction, particularly in underdeveloped regions. Despite the significant efficacy of pesticides in pest control, their extensive use has led to the drug-fast of insecticide resistance. Developing of new environmentally friendly plant-based pesticides is an urgent necessity. In this study, a series of diaryl ether compounds containing propargyloxy and sulfonamide groups were designed. The synthesis of these 36 compounds primarily relied on nuclear magnetic resonance for structure determination, while single-crystal X-ray diffraction was employed for certain compounds. Meanwhile, the insecticidal activities against Mythimna separata were also assessed. Some of the compounds exhibited significantly enhanced activity, the LC50 value of the highest activity compound TD8 (0.231 mg/mL) demonstrating respective increases by 100-fold compared to the plant pesticide celangulin V (23.9 mg/mL), and a 5-fold increase with the positive control L-1 (1.261 mg/mL). The interaction between the target compound and the target, as well as the consistency of the target, were verified through symptomological analysis and molecular docking. The structure-activity relationships were also conducted. This study offered a novel trajectory for the advancement and formulation of future pesticides.

Diversifying the benzenesulfonamide scaffold for potential V-ATPase inhibitors: synthesis and insecticidal activity evaluation

Celangulin V is a natural β-dihydroagarofuran derivative isolated from Celastrus angulatus which shows insecticidal activity in many agricultural pests. Using celangulin V as a molecular probe, we find out a new pesticide target: subunit H of V-ATPase. To explore the potential application of this novel target, lead sulfonamides have been found through virtual screening. Combined with the previous work, 46 sulfonamide derivatives are designed and synthesized. All target compounds are first screened for their insecticidal activities against Mythimna separata. The results of bioassay reveal that most of the designed compounds exhibit significant insecticidal activities against third-instar larvae of M. separata under the concentration of 10 mg/mL, and compound 8.4 shows the highest activity with LC50 value of 1.72 mg/mL, 15-fold smaller than that of celangulin V (25.89 mg/mL). Molecular docking results further indicated that compound 8.4 might serve as a potential inhibitor of the subunit H of V-ATPase. This study provides a potential sulfonamide candidate compound for the M. separata control.

Design, synthesis and insecticidal activities of 4-propargyloxybenzene sulfonamide derivatives substituted with amino acids

Sixty-nine 4-propargyloxybenzene sulfonamide derivatives with different amino acids as amino substituent were synthesized and evaluated for their insecticidal activity against third-instar Mythimna separate. The bioassay results revealed that some derivatives bearing amino acid ester group performed good insecticidal activity against third-instar M.separata, such as the LC₅₀ values of D18 and D19 were 4.28 and 2.96 mg/ml after 48 h, in particular, the LC₅₀ of D16 was 2.38 mg/ml and the activity was improved by 14 times compared to celangulin V (34.48 mg/ml). The above results provided theoretical and experimental basis for the discovery of novel insecticidal active compounds.

Synthesis and insecticidal activities of 4-(propargyloxy) benzenesulfonamide derivatives

A series of 4-(propargyloxy) benzenesulfonamide derivatives with different substituents on the benzene ring were synthesized and evaluated for their insecticidal activity. Some of the compounds showed good insecticidal activity against Mythimna separata, and the LC₅₀ value of the most active compound B2.5 was 0.235 mg/ml. Ultrastructural changes in the midgut epithelial cells of Mythimna separata were observed using transmission electron microscopy, and severe structural damage was found in microvilli, mitochondria and rough endoplasmic reticulum. It indicates that the possible site of action of these benzenesulfonamides is the cytoplasmic membrane and endomembrane system of the midgut epithelial cells. The above provides a basis for the development of novel insecticidal active compounds with a novel mechanism of action.