title: Trifluoroacetyl neonicotinoid insecticides with enhanced hydrophobicity and effectiveness.
abstract: Neonicotinoids with nitro- or cyanoimino substituents are extensively utilized as plant-mobile (systemic) insecticides controlling the piercing-sucking insect pests. This investigation considers structural features of neonicotinoids with trifluoroacetyl pharmacophores, which may confer enhanced hydrophobicity and effectiveness. Fifteen trifluoroacetyl neonicotinoid analogues [=NC(O)CF(3) and =CHC(O)CF(3)] are therefore prepared to evaluate the hydrophobicity index, toxicity to houseflies (Musca domestica), and binding affinity to the Musca nicotinic receptor. The =NC(O)CF(3) and =CHC(O)CF(3) compounds showed a higher hydrophobicity than that of nitro- or cyanoimino analogues. The intrinsic insecticidal activities (defined by intrathoracic injection with a synergist pretreatment) of test compounds were well-correlated to their target site potencies. Although nitro or cyano neonicotinoids were not toxic via the topical application route in the absence of a synergist, trifluoroacetyl analogues exhibited excellent insecticidal activity under the same condition. Accordingly, the increased hydrophobicity of trifluoroacetyl neonicotinoids presumably improves the penetrability of compound into insect integument and insecticidal effectiveness.
authors.affiliation: The United Graduate School of Agricultural Science, Gifu University, Gifu, Japan.
authors.forename: Ikuya
authors.initials: I
authors.lastname: Ohno
authors.forename: Motohiro
authors.initials: M
authors.lastname: Tomizawa
authors.forename: Asako
authors.initials: A
authors.lastname: Aoshima
authors.forename: Satoru
authors.initials: S
authors.lastname: Kumazawa
authors.forename: Shinzo
authors.initials: S
authors.lastname: Kagabu
mesh_terms: D000691:Anabasine / Q000494:pharmacology*; D000818:Animals; D006793:Houseflies; D007306:Insecticides / Q000494:pharmacology*
chemical_list: D007306:Insecticides; D000691:Anabasine