Synthesis and insecticidal evaluation of novel N'-tert-butyl-N'-substitutedbenzoyl-N-5-chloro-6-chromanecarbohydrazide derivatives.

A series of novel N'-tert-butyl- N'-substitutedbenzoyl-N-5-chloro-6-chromanecarbohydrazide derivatives were synthesized, and their larvicidal activities against Oriental armyworm were evaluated. The results of bioassays indicated that most of these title compounds exhibit higher larvicidal activities than RH-5849, and several of them somewhat lower than the commercial insecticide tebufenozide. The larvicidal activities are strongly associated with the types and patterns of substitution on the benzene, and 3,5-dimethyl, 2-nitro-4-chloro and 3-methyl derivatives are most prominent in increasing activity. Toxicity assays indicated that these derivatives could induce a premature, abnormal, and lethal larval moult.

Synthesis, crystal structure and biological activity of aryl [(N,N'-diacyl-N'-tert-butylhydrazino)thio]methylcarbamates.

A series of novel aryl [(N,N'-diacyl-N'-tert-butylhydrazino)thio]methylcarbamates were synthesized by the reaction of aryl (chlorothio)methylcarbamates with N,N'-diacyl-N-tert-butylhydrazines in the presence of sodium hydride. X-Ray single crystal diffraction of 2-isobutylphenyl [(N,N'-dibenzoyl-N'-tert-butylhydrazino)thio]methylcarbamate demonstrated the presence of N-S-N bonding. All of the compounds exhibited excellent larvicidal activities. Toxicity assays indicated that the products had knockdown activities of aryl methylcarbamates at higher concentrations and insect growth regulator activities of diacylhydrazines at lower concentrations.

Synthesis and insecticidal evaluation of novel N-oxalyl derivatives of tebufenozide.

A series of novel N '-tert-butyl-N '-3,5-dimethylbenzoyl-N-aryloxyoxalyl-N-4-ethylbenzoyl hydrazines containing a carboxylic acid or ester substituent on the aryl were synthesized, and their larvicidal activities were evaluated. The results of bioassays indicated that some of these title compounds exhibit higher larvicidal activities than RH5849 (N-tert-butyl-N,N '-dibenzoylhydrazine), but they are not good compared to the parent compound (tebufenozide). The carboxylic acid substituent on the aryl was essential for high larvicidal activity. Compared to the parent compound, these derivatives displayed different physical properties, for example, better solubility in organic solvents. Toxicity assays indicated that these derivatives could induce a premature, abnormal, and lethal larval molt.

Synthesis and bioassay evaluation of 1-(4-substitutedideneaminooxymethyl)-phenyl-3-(2,6-difluorobenzoyl)ureas.

A variety of novel 1-(4-substitutedideneaminooxymethyl)-phenyl-3-(2,6-difluorobenzoyl)ureas were designed and synthesized by the reaction of 4-substitutedideneaminooxymethyl aniline with 2,6-difluorobenzoyl isocyanates in good yields. The title compounds were soluble in most organic solvents, which should make them easier to use. The preliminary bioassay showed that some of the title compounds show excellent insecticidal activity against Mythimna separata at the dosage of 25 mg kg(-1) and moderate insecticidal activity against Nephotettix cincticeps at the dosage of 500 mg kg(-1). Toxicity assays indicated that these title compounds cause in M. separata and N. cincticeps such symptoms of toxicity as discolouration, and weight loss, and cessation of feeding and lethal. One title compound exhibited acaricidal activity against Tetranychus urticae.