Tefluthrin

>500 g/L in acetone, hexane, toluene, dichloromethane and ethyl acetateTefluthrin is an organic compound. It is classified as a pyrethroid, meaning that in terms of chemical structure, it resembles the naturally occurring insecticide pyrethrin. It was designed to be effective against soil pests. With an LD50 for rats of 29 mg/kg, tefluthrin is one of the most toxic pyrethroids. Tefluthrin functions through binding to the voltage-gated sodium channels of organisms and thereby increasing the inflow of sodium into the cells. Tefluthrin is an organic compound. It is classified as a pyrethroid, meaning that in terms of chemical structure, it resembles the naturally occurring insecticide pyrethrin. It was designed to be effective against soil pests. With an LD50 for rats of 29 mg/kg, tefluthrin is one of the most toxic pyrethroids. Tefluthrin functions through binding to the voltage-gated sodium channels of organisms and thereby increasing the inflow of sodium into the cells. Tefluthrin was introduced for legalisation in the European Union in 1986 in Belgium. It took, however, until December 5, 2008 to add tefluthrin to a group of substances which are authorized as plant protection products. On January 1, 2012 tefluthrin was re-approved for use in the European Union. Tefluthrin is a polyfluoroaryl carbinol, consisting of an aryl group with multiple fluoride atoms and a carbon chain attached. One way of synthesising polyfluoroaryl carbinols is by direct C-H metalation of fluorated arenes and addition to aldehydes. However, the multiple C-H metalations proved to be difficult without the right directing group. Magnesated polyfluoroaryl carbinols were used by scientists from the Key laboratory of Macromolecular Science of Shaanxi Province in China to mimic a Grignard reagent used to facilitate the mg prompted C-H metalation. This method could be successfully executed with the Grignard reagent isopropylmagnesium bromide, isopropylmagnesium chloride, or ethylmagnesium bromide.The tefluthrin intermediate, 4-methyl-2,3,5,6-tetrafluorobenzyl alcohol, could be reacted with cis-Z 3-(2-chloro-l,l,l-trifluoro-2-propenyl)-2,2-dimethylcyclopropane carbonyl chloride to give tefluthrin. Phase I metabolism of tefluthrin proceeds via both oxidation and hydrolysis.Initial targets for oxidation are protruding methyl groups. These methyl groups can specifically be found on the cyclopropane ring and on the tetrafluorobenzene ring and are oxidized to alcohol groups. These alcohol groups can be further oxidized into carboxylic acid groups.Hydrolysis of tefluthrin happens at the ester bond which results in a cyhalothric acid and a tetrafluorobenzene alcohol, which can be further oxidized into a carboxylic acid.In phase II metabolism, the phase I metabolites are glucuronidated on any available alcohol groups to facilitate membrane transport and eventually excretion. Pyrethroid insecticides, and therefore also tefluthrin, influence the voltage-gated sodium channels of organisms. The sodium channels are heteromultimeric complexes consisting of one large ?-subunit and two smaller ?-subunits. The binding site of tefluthrin is on the ?-subunit, which also forms the pore of the channel. Tefluthrin alters the functioning of the voltage-gated sodium channels by blocking the inactivation and slowing the deactivation of the channels. This results in persistent and prolonged activation of sodium channels and inflow of sodium. However, there are many different forms of sodium channels. In mammals 9 different sodium channel ?-subunits have been identified (named Nav1.1-Nav1.9). The channel isoforms differ in affinity for tefluthrin, for example the Nav1.6 is at least 15-fold more sensitive than the Nav1.2 isoform. Also the action of tefluthrin is stereoselective. The cis isomer is up to 10-fold more toxic than the trans isomer, and also the binding differs between both isomers. Tefluthrin provided consistently good results when applied properly against certain Cryptophagidae which is a family of beetles. It was tested on the Atomaria linearis that is a species of silken fungus beetle native to Europe. Organisms that are related to these animals seem to share this susceptibility to the compound. This includes a lot of soil pests (springtails; symphylids; millipedes; pygmy beetle; fire ants; rootworms; wireworms; white grubs). The effective dose is 60 ml with a 100.000 seeds. It is not allowed to higher this concentration because of resistance management. It is preferred over other Pyrethrins because of its effects on lots of soil pests, high selectivity and stimulation of growth according to Syngenta, the company which produces the insecticide. The use of tefluthrin on soil pests can have several side effects. At first it was investigated if tefluthrin will spread due to rain. Heavy rainfall was stimulated in a model to see whether the tefluthrin will be adsorbed or not. In the used model 85% of the total used tefluthrin was recovered out of the simulated rain water. To conclude anything on the consequences of the real environment, more research is needed. Secondly adsorption of the tefluthrin by plants is possible. This was investigated by measuring the yield of the corn fields were the tefluthrin was used. When normal corn was used there was a slight loss of yield. Which implies the tefluthrin will enter the plant and affect it. When genetically modified corn was used the yield was not affected by tefluthrin.