Design, synthesis, and insecticidal evaluation of new pyrazole derivatives containing imine, oxime ether, oxime ester, and dihydroisoxazoline groups based on the inhibitor binding pocket of respiratory complex I

J Agric Food Chem. 2013 Sep 18;61(37):8730-6. doi: 10.1021/jf402719z. Epub 2013 Sep 5.

Abstract

On the basis of complex I receptor protein binding site and commercial tebufenpyrad and tolfenpyrad, four series of novel pyrazole-5-carboxamides containing imine, oxime ether, oxime ester, and dihydroisoxazoline were designed and synthesized via the key intermediate 4-chloro-3-ethyl-N-(4-formylbenzyl)-1-methyl-1H-pyrazole-5-carboxamide. The structures of target compounds were confirmed by ¹H NMR and high-resolution mass spectrum (HRMS). The results of bioassays indicated that the target compounds possessed good-to-excellent activities against a broad spectrum of insects such as cotton bollworm (Helicoverpa armigera), spider mite (Tetranychus cinnabarinus), bean aphid (Aphis craccivora), and mosquito (Culex pipiens pallens), but gave different structure-activity relationships for each species. Compounds containing imine showed high insecticidal activity against cotton bollworm. Especially, stomach activity of compounds 5-1c was 60% at 11 mg kg⁻¹. The compounds also had good activities against bean aphid and mosquito. The foliar contact activity of compounds 5-1a, 5-1b, 5-1e, 5-3c, and 5-3d against bean aphid were 90, 100, 90, 90, and 90%, respectively, at 200 mg kg⁻¹. The activity of compound containing dihydroisoxazoline moiety (5-4) against mosquito was 60% at 1 mg kg⁻¹, which was near that of tebufenpyrad. The introduction of dihydroisoxazoline structure (5-4) was advantageous to improve the activity of the compound against adult mites compared with other structures; the miticidal activity of 5-4- against adult mites was 60% at 50 mg kg⁻¹.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Binding Sites
  • Drug Design*
  • Electron Transport Complex I / antagonists & inhibitors*
  • Electron Transport Complex I / chemistry
  • Esters / chemical synthesis
  • Esters / chemistry
  • Esters / pharmacology
  • Ethers / chemical synthesis
  • Ethers / chemistry
  • Ethers / pharmacology
  • Imines / chemical synthesis
  • Imines / chemistry
  • Imines / pharmacology
  • Insect Proteins / antagonists & inhibitors*
  • Insect Proteins / chemistry
  • Insecta / drug effects
  • Insecticides / chemical synthesis
  • Insecticides / chemistry*
  • Insecticides / pharmacology*
  • Molecular Structure
  • Oximes / chemical synthesis
  • Oximes / chemistry
  • Oximes / pharmacology
  • Pyrazoles / chemical synthesis
  • Pyrazoles / chemistry*
  • Pyrazoles / pharmacology*
  • Structure-Activity Relationship

Substances

  • Esters
  • Ethers
  • Imines
  • Insect Proteins
  • Insecticides
  • Oximes
  • Pyrazoles
  • Electron Transport Complex I