Synthetic pyrethroids bifenthrin

Pyrethroids. More accurately described as the synthetic pyrethroids, this group of compounds has been used extensively in wood preservation for control of both beetles and termites. Activity, cost and performance characteristics vary depending upon the specific compound but most readily accepted for use in wood preservative formulations are permethrin, cypermethrin, deltamethrin, bifenthrin and cyfluthrin. In terms of activity against wood boring beetles, cyfluthrin is estimated to be 20 times more effective than permethrin, 10 times as effective as cypermethrin and twice as effective as deltamethrin when compared in laboratory evaluative procedures. However, in practice other factors need to be considered, particularly the relative vapour pressures (and therefore evaporative loss) and, in wood in soil contact, the rate of biotransformation by colonising bacteria. The pyrethroids are effective as neurotoxins, and are axonic poisons. 

Two synthetic pyrethroid insecticides, bifenthrin and permethrin (3-phenoxybenzyl (lR5)-cis-fra s-3-(2,2-dichlorovinyl)-2,2-dimcthylcyclopropane-carboxylate), are the major runoff constituents considered in our monitoring and evaluation studies. Bifenthrin has a solubility of <1 ppb, and a Koc of240,000 ml g. Permedirin has a solubility of 6 ppb in water, and a Ka- of 100,000 ml g (5). The stroi adsorption on soil suggests that a large fiaction of the pesticide is associated wifii die suspended solids in nursery runoff. This determines that the downstream distribution of these pesticides is closely related to distribution of sediments, and that practices aiming to remove suspended solids from runoff will also be effective in reducing the level of these pesticides. 

CF3CCl2-substituted alcohols in good yields. In this case, when insitu-geaeiaied zinc alkoxides are subsequently treated with AC2O and zinc dust at 50°C, trifluoromethylated alkenes can be obtained in good yields (Scheme 26.33). This practical one-pot synthesis can be applied for the preparation of highly potent insecticides, so-called synthetic pyrethroids, such as bifenthrin and others. ... 

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