High Value Utilization of an Avermectin Fermentation Byproduct: Novel B2a Derivatives as Pesticide Candidates

Abstract

In an effort to develop novel molecules with suitable insecticidal activities, 23,24-alkene-avermectin B2a derivatives have been synthesized via a one-pot multistep reaction using avermectin B2a, a byproduct of avermectin fermentation, as a starting material. All products and intermediates were characterized by 1 H NMR, 13 C NMR, and high-resolution mass spectrometry. Bioassay results showed that the LC 50 values of compounds 4 and 9 against Meloidogyne incognita were 0.63 and 0.50 mg/L, respectively, similar to that of avermectin (0.46 mg/L). Importantly, the LC 50 values of compound 9 against Tetranychus cinnabarinus and Mythimna separate were 0.0067 and 0.047 mg/L, respectively, superior to that of avermectin. Through field experiments, it could be found that spraying 0.25% water-dispersible granules of compound 9 345 g ha −1 could effectively control M. incognita outbreaks, with an efficacy of 84.9%. Combined with toxicity experiments, it could be further inferred that compound 9 may be useful as a lowtoxicity pesticide. In summary, we efficiently synthesized a new B2a derivative as a potential pesticide and offered an important way for improving the utilization efficiency of avermectin fermentation products. In doing so, the environmental pollution associated with fermentation byproducts may be greatly reduced, potentially enabling a sustainable avermectin fermentation process.

Spiro Derivatives in the Discovery of New Pesticides: A Research Review

“…79 Xu et al found that the insecticidal activities of a series of abamectin B2a derivatives against Tetranychus cinnabarinus, Mythimna separate, and Meloidogyne incognita were close to or even higher than those of abamectin, which is a potential insecticide friendly to the environment. 80 In addition, the insecticidal activities of compound 48 against Aedes aegypti and Musca domestica were demonstrably better than those of Pyrethrin and trans-chrysanthemic acid, 81 and the compounds high activity insecticidal results were confirmed via favorable combinations with the important active amino acids of Aedes aegypti target proteins. Tricyclic spiranoid lactones are also natural, bioactive chemicals, but fused lactones are rarely reported.…”

“…Compound 47 also reported its insecticidal activity against Bursaphelenchus xylophilus , and although the effects were lower than observed for avermectin, it provided ideas for the application of spironaphthalene derivatives in pesticides . Xu et al found that the insecticidal activities of a series of abamectin B2a derivatives against Tetranychus cinnabarinus , Mythimna separate , and Meloidogyne incognita were close to or even higher than those of abamectin, which is a potential insecticide friendly to the environment . In addition, the insecticidal activities of compound 48 against Aedes aegypti and Musca domestica were demonstrably better than those of Pyrethrin and trans -chrysanthemic acid, and the compounds high activity insecticidal results were confirmed via favorable combinations with the important active amino acids of Aedes aegypti target proteins.…”

“…According to the literature summary, the introduction of active spirocyclic structures into neonicotinoid compounds, indole compounds, and natural products improves their insecticidal activities against Lepidoptera , Hemiptera , and Diptera insects and other pests. − Neonicotinoids are currently the most widely used insecticides. They act on nicotinic acetylcholine receptors in the insect’s nervous system and peripheral nerves, causing paralysis. , These compounds are highly efficient and selective broad spectrum insecticides.…”

Preparation and Characterization of Avermectin B2 Microcapsules and Effective Control of Root-Knot Nematodes

“…Avermectin is a sixteen-membered macrolide insecticide extracted from the MA-4680 strain of Streptomyces avermitilis that can be isolated from the soil. A number of avermectin derivatives exist, namely, A1a, A2a, A1b, A2b, B1a, B2a, B1b, and B2b, − wherein avermectin B2 is known to exhibit a strong nematocidal activity. , Although this compound has been widely used to control crop diseases caused by infectious nematodes (e.g., root-knot nematodes, root rot nematodes, cyst nematodes, and stem nematodes), , it is susceptible to photolysis and a has poor mobility in the soil, thereby hindering its uptake by plants and lowering its potential efficacy . However, despite the fact that various avermectin B2 preparations are available on the market, such as emulsifiable concentrate (EC), microemulsion (ME), and emulsion in water (EW), , they are unable to solve the above issues.…”