title: Quantitative structure-activity studies of insect growth regulators: XIX. Effects of substituents on the aromatic moiety of dibenzoylhydrazines on larvicidal activity against the beet armyworm Spodoptera exigua.
abstract: Larvicidal activity against the beet armyworm, Spodoptera exigua (Hübner), was measured after topical treatment for a series of N-tert-butyl-dibenzoylhydrazines having various substituents in the benzoyl (A-ring) moiety closer to the tert-butyl group, the other benzoyl (B-ring) moiety being unsubstituted. The effects of substituents on the larvicidal activity were analyzed using the classical quantitative structure-activity relationship (QSAR) procedure. Introduction of hydrophobic substituents with a small volume into any position was favourable to activity. The existence of electron-withdrawing substituents at ortho positions was also favourable to activity. For multi-substituted compounds, physico-chemically unknown unfavourable factors were suggested to remain after separating common substituent effects derived from QSAR for mono-substituted analogues. With the exception of the unsubstituted compound RH-5849, the effect of substituents in the A-ring moiety on the larvicidal activity was similar to those found with the lepidopteran rice stem borer, Chilo suppressalis (Walker). The larvicidal activity of RH-5849 against S exigua was significantly lower than the value predicted from the correlation between activities against S exigua and C suppressalis. Topical treatment with piperonyl butoxide, a synergist inhibiting oxidative metabolism, slightly enhanced the larvicidal activity of RH-5849 against S exigua.
authors.affiliation: Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan. naka@kais.kyoto-u.ac.jp
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Nakagawa
authors.forename: Guy
authors.initials: G
authors.lastname: Smagghe
authors.forename: Luc
authors.initials: L
authors.lastname: Tirry
authors.forename: Toshio
authors.initials: T
authors.lastname: Fujita
mesh_terms: D000465:Algorithms; D000818:Animals; D006834:Hydrazines / Q000737:chemistry / Q000633:toxicity; D057927:Hydrophobic and Hydrophilic Interactions; D007605:Juvenile Hormones / Q000737:chemistry / Q000633:toxicity*; D007814:Larva / Q000187:drug effects / Q000254:growth & development; D007915:Lepidoptera / Q000187:drug effects / Q000254:growth & development*; D007928:Lethal Dose 50; D010882:Piperonyl Butoxide / Q000633:toxicity; D021281:Quantitative Structure-Activity Relationship; D018411:Spodoptera / Q000187:drug effects / Q000254:growth & development
chemical_list: D006834:Hydrazines; D007605:Juvenile Hormones; C056565:1,2-dibenzoyl-tert-butylhydrazine; D010882:Piperonyl Butoxide