Synthesis and insecticidal activities of 5-deoxyavermectin B2a oxime ester derivatives

Abstract

Three series of avermectin B2a oxime ester derivatives were synthesized and evaluated for their insecticidal activity.

Synthesis, Optimization, and Evaluation of Glycosylated Naphthalimide Derivatives as Efficient and Selective Insect β-N-Acetylhexosaminidase OfHex1 Inhibitors

“…Target compounds that efficiently inhibited OfHex1 were further tested for their insecticidal activity against Myzus persicae and Plutella xylostella according to previous studies. , Test compounds were dissolved in dimethyl sulfoxide (DMSO) and diluted to a final concentration of 600 and 200 μg/mL. Hexaflumuron was used as a positive control, and DMSO was used as a negative control.…”

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

“…AO is composed of approximately 10% B1a functioning as the insecticidal active ingredient and 90% B2a as a byproduct. However, due to the general public’s attention to environmental protection, China has banned the use of AO since 2012 . Large quantities of AOs are produced each year, and due their high toxicity, their disposal requires special treatment, resulting in both high cost and waste of resources. − Therefore, finding new ways to improve the utilization of the byproduct B2a is of great academic and practical value with regards to atom economy, sustainable chemistry, and agriculture …”

“…These structural differences result in a loss of insecticidal activity of B2a. Various preliminary studies attempted to convert B2a to B1a by 23-OH elimination; however, harsh reaction conditions and the low overall yields observed prevented large-scale applicability. , A Mn­(dpm) 3 -catalyzed olefin hydration reaction was conducted to migrate the 2,3 double bond, but the biological activity was lower than that of B1a. , In an effort to develop new B2a derivatives, our group , has designed and synthesized several series of B2a derivatives since 2015. ,, We have demonstrated that avermectin B2a derivatives bearing oxime ester moieties showed higher insecticidal activities against Myzus persicaeand Caenorhabditis elegans in comparison with avermectin B2a …”

“…20−22 According to the currently available technologies, every 1000 kg of B1a produces approximately 500−600 kg of the byproduct (avermectin B2a, Figures 1 and 2). 23 Avermectin ointment (AO), the mother liquor formed during the purification process of B1a, has been used in the production of avermectin emulsifiable concentrate in China for a long time. AO is composed of approximately 10% B1a functioning as the insecticidal active ingredient and 90% B2a as a byproduct.…”

“…30,31 In an effort to develop new B2a derivatives, our group 25,26 has designed and synthesized several series of B2a derivatives since 2015. 23,31,33 We have demonstrated that avermectin B2a derivatives bearing oxime ester moieties showed higher insecticidal activities against Myzus persicaeand Caenorhabditis elegans in comparison with avermectin B2a. 15 On the basis of the above information and in order to reduce waste production caused by AO, we herein report novel avermectin B2a derivatives that were both rationally designed and synthesized by direct dehydration of the remaining C23hydroxy moiety.…”