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Construction of oxime ester derivatives of osthole from Cnidium monnieri , and evaluation of their agricultural activities and control efficiency
Author(s) -
Ren Zili,
Lv Min,
Li Tianze,
Hao Meng,
Li Shaochen,
Xu Hui
Publication year - 2020
Publication title -
pest management science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.296
H-Index - 125
eISSN - 1526-4998
pISSN - 1526-498X
DOI - 10.1002/ps.6056
Subject(s) - mythimna separata , chemistry , natural product , regioselectivity , stereochemistry , oxime , organic chemistry , botany , biology , lepidoptera genitalia , catalysis
Abstract BACKGROUND In order to discover natural‐product‐based pesticidal candidates, a series of coumarin‐like derivatives containing oxime ester fragments at the C‐8 position were prepared by structural modification of osthole, a natural plant product isolated from Cnidium monnieri. Their pesticidal activities were evaluated against two typically fruit trees/crop‐threatening agricultural pests, Mythimna separata Walker and Tetranychus cinnabarinus Boisduval. RESULTS Osthole was regioselectively oxidized by selenium dioxide to give the E ‐isomer, (2′ E )‐3′‐formaldehydylosthole ( 2 ). Four key steric structures of 2 , (2'E, 4'E)‐(o‐chloropyrid‐3‐ylcarbonyl)oximinylosthole ( 4o ), (2'E, 4'E)‐(styrylcarbonyl)oximinylosthole ( 4t ), and (2'E, 4'E)‐(acetyl)oximinylosthole ( 4w ) were undoubtedly confirmed by X‐ray crystallography. Against T. cinnabarinus , it is noteworthy that (2′ E , 4′ E )‐( p ‐chlorophenylcarbonyl)oximinylosthole ( 4c ) exhibited over three‐fold more potent acaricidal activity of the precursor osthole, with especially good control efficiency observed in the glasshouse. Against M. separata , compounds 4c and (2′ E , 4′ E )‐( p ‐nitrophenylcarbonyl)oximinylosthole ( 4f ) showed the most pronounced growth inhibitory activity. The relationships between their structures and agricultural activities also were studied. CONCLUSION These results demonstrate that compound 4c could be further structurally modified as pesticidal agents. It will lay the foundation for future application of osthole derivatives as pesticides. © 2020 Society of Chemical Industry