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Denise P Cudworth,
Vidyadhar B Hegde,
Maurice C H Yap,
Katherine A Guenthenspberger,
Christopher T Hamilton,
James T Pechacek,
Peter L Johnson,
Scott J Bis,
F Eugene Tisdell, James E Dripps,
Timothy J Bruce,
Leonard P Dintenfass,
James M Gifford,
Laura L Karr,
Margaret K Kempe,
D'Lee C McCormick,
Joseph R Schoonover
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ABSTRACT: An extended lipophilic system that incorporated some key elements of first-generation 2,6-dihaloaryl actives, such as 1, demonstrated desirable efficacy against chewing insects as well as sap-feeding insects. These four-ring systems, based on 2, were accessed primarily via Suzuki couplings of halothiophene derivatives with appropriately substituted boronic acids. In particular, phenylthiophene systems that incorporated haloxyether groups, such as those in 3, 4, and 5, had the broadest spectrum of activity across chewing and sap-feeding insect pests. Expansion of this structure-activity relationship to include compounds with differing substitution patterns on the thiophene-C-ring and aryl-D-rings was undertaken. The synthesis and insecticidal activity of 3-aryl-5-(thiophen-2-yl)-1-methyl-1H-[1,2,4]triazoles will be described.
Journal of Agricultural and Food Chemistry 10/2007; 55(18):7517-26. · 2.82 Impact Factor
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ABSTRACT: A benzoylphenylurea insect growth regulator with the common name noviflumuron was evaluated for use as a baiting toxicant against the eastern subterranean termite, Reticulitermes flavipes (Kollar). Noviflumuron demonstrated significantly greater potency and faster speed of action compared with the commercial standard hexaflumuron. In addition, noviflumuron was not a feeding deterrent on filter paper at concentrations of up to 10,000 ppm. The rates of uptake, clearance, and insect-to-insect transfer of [14C] noviflumuron were measured in R. flavipes in laboratory assays and compared with those previously reported for [14C]hexaflumuron. Under a continuous exposure regime, the uptake profile for noviflumuron was similar to that for hexaflumuron, although the time period of maximal uptake was shorter for noviflumuron. Noviflumuron was cleared from termites in a first order process with a half-life of approximately 29 d, whereas the half-life of hexaflumuron was much shorter (8-9 d). Noviflumuron was efficiently transferred from treated to untreated termites by trophallaxis via kinetics similar to those reported for hexaflumuron; however, the systemic dose of noviflumuron required to result in toxicity of R. flavipes was found to be at least two- to three-fold less than that of hexaflumuron. The faster activity of noviflumuron compared with hexaflumuron in R. flavipes can be at least partially explained by the combination of slower clearance and greater intrinsic activity.
Journal of Economic Entomology 05/2004; 97(2):593-600. · 1.70 Impact Factor
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Jack G. Samaritoni,
Lena Arndt,
Timothy J. Bruce, James E. Dripps,
James Gifford,
Christopher J. Hatton,
William H. Hendrix,
Joseph R. Schoonover,
George W. Johnson,
Vidyadhar B. Hegde,
Scott Thornburgh
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ABSTRACT: Treatment of 5-amino-4-chloro-3-methylisothiazole (3) with the acid chloride of [p-[(α,α,α-trifluoro-p-tolyl)oxy]phenyl]acetic acid (6) afforded the amide N-(4-chloro-3-methyl-5-isothiazolyl)-2-[p-[(α,α,α-trifluoro-p-tolyl)oxy]phenyl]acetamide (1), which was substituted with various alkyl groups in an effort to alleviate toxicity toward non-target organisms through a proinsecticide approach. Alkylations of 1 under a variety of reaction conditions afforded two major products which were derived from amide-nitrogen substitution, N-alkyl-N-(4-chloro-3-methyl-5-isothiazolyl)-2-[p-[(α,α,α-trifluoro-p-tolyl)oxy]phenyl]acetamides (7), and ring-nitrogen substitution, N-(2-alkyl-4-chloro-3-methyl-3-isothiazolin-5-ylidene)-2-[p-[(α,α,α-trifluoro-p-tolyl)oxy]phenyl]acetamides (8). Derivatives 7 and 8 were found to exhibit lessened toxicity to trout as well as insects, but, in general, efficacy toward insects was retained to a greater degree. In particular methoxymethyl, ethoxymethyl, ethyl, and ethyl-d5 substituents demonstrated the best combination of insect efficacy and safening toward trout. Significantly different in vivo efficacies of the N-methyl and N-CD3 analogs suggest that 7 and 8 are proinsecticides requiring activation by dealkylation. Keywords: Isothiazolylphenylacetamides; isothiazolinylidenephenylacetamides; insect control; proinsecticide; synthesis
05/1997;
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ABSTRACT: Improvements in the efficacy and spectrum of the spinosyns, novel fermentation derived insecticide, has long been a goal within Dow AgroSciences. As large and complex fermentation products identifying specific modifications to the spinosyns likely to result in improved activity was a difficult process, since most modifications decreased the activity. A variety of approaches were investigated to identify new synthetic directions for the spinosyn chemistry including several explorations of the quantitative structure activity relationships (QSAR) of spinosyns, which initially were unsuccessful. However, application of artificial neural networks (ANN) to the spinosyn QSAR problem identified new directions for improved activity in the chemistry, which subsequent synthesis and testing confirmed. The ANN-based analogs coupled with other information on substitution effects resulting from spinosyn structure activity relationships lead to the discovery of spinetoram (XDE-175). Launched in late 2007, spinetoram provides both improved efficacy and an expanded spectrum while maintaining the exceptional environmental and toxicological profile already established for the spinosyn chemistry.
Journal of Computer-Aided Molecular Design 22(6-7):393-401. · 3.39 Impact Factor
