SYNTHESIS AND BIOLOGICAL EVALUATION OF NEW PYRETHROIDS HAVING HALOGEN, KETO, OR NITRO GROUP-CONTAINING SUBSTITUENTS

Thirteen pyrethroid esters, most of which contain strong electron-withdrawing groups (e.g., halomethylketo and nitro groups) in the side chain of the cyclopropane acid moiety, have been synthesized. The synthesis involved the reaction of various active methylene compounds with 3-formyl-2,2-dimethylcyclopropanecarboxylic esters of known pyrethroid alcohols. Rather than the usually employed Wittig reaction for these syntheses, the novel pyrethroid acid moieties were prepared by amino acid-catalyzed Knoevenagel condensations under mild conditions. Preliminary toxicity studies of the pyrethroid esters, against several insect and one mite species, were conducted. Two of these compounds had good repellent activity against the twospotted spider mite (Tetranychus urticae) at 100 ppm, and six of them had medium insecticidal activity against either black bean aphid (Aphis fabae) or western potato leafhopper (Empoasca abrupta) at 10 ppm.