The Design, Synthesis And Biological Activity Of Novel Fluorine-containing Pyridine Derivatives

Compounds containing trifluoromethyl pyridine structure play an important role in the creation of pesticides.In this paper,two series of trifluoromethyl pyridine deravitives?61compounds?were disigned and synshthzed by the introduction of diamide and oxdiazole heterocyclic structure.And the sturcture of them were confirmed by ¹H NMR?¹³C NMR?¹⁹F NMR and HRMS.The insecticidal activityagainst Plutella xylostella,Mythimna separata,Nilaparvata lugens,Aphis craccivora were tested,and quantitative structure-activity relationship?3D-QSAR?were also discussed.The results are as follows:1.33 trifluoromethyl pyridine diamides containing phthalic diamide were designed and synthesized by cooperation the substructural unit of trifluoromethyl pyridine and phthalic diamid.The results of insecticidal activity against Plutella xylostella indicated that most of the compounds had good insecticidal activity with LC₅₀ ranged from 3.7 to 2162.2 mg·L^-1.In particularly,LC₅₀ of compound H28 and H33 to Plutella xylostella were 4.8 mg·L^-1 and 3.7mg·L^-1 respectively.The preliminary structure-activity relationship reveaaled that the insecticidal activity of the compounds is affected by substitution of the benzene ring and R1chain.When the phenyl was substituted by 4-chloro-6-methyl,the compound has the best activity,followed by 2,4-dichloro and 6-methyl substitution.on the contrary,the compound with 4,6-difluoro and 4-chloro showed poor insecticidal activity.As for the R1,Theses compounds with isopropyl?H33?and cyclopropyl?H28?displayed good activity,however,the introduction of trifluoroethyl and difluoroethyl can decresed the activity.2.28 novel trifluoromethyl pyridine deravitives with the structure of 1,3,4-oxadiazole moiety were designed,synthesized,and characterizatied,as well as its bioactivity for Mythimna separate,Plutella xylostella etc.was evaluated.most of the title compounds show100%insecticidal activity at 500 mg·L^-1and>80%activity at 250 mg·L^-11 against the two pests,and their LC₅₀ ranged from 30.8 to 284.6 mg·L^-1.CoMFA and CoMSIA models with good predictability were established.The results showed that the substituents with appropriate bulk at 2 and 4 position of phenyl ring could increase the insecticidal activity,and the introduction of electronegative groups at the 2 and 5 positions was beneficial to the biological activity.