Permethrin

Permethrin (NRDC-143) is an insecticide, acaricide, and insect repellent; functions as a neurotoxin, affecting neuron membranes by prolonging sodium channel activation.

Yellow-brown to brown liquid, which sometimes tends to crystallize at room temperature (technical grade).Permethrin, a pyrethroid insecticide with little mammalian toxicity, has been marketed as a tick repellent. Permethrin is the only synthetic pyrethroid that is used worldwide for head lice. The spray formulation is the most widely available form. Once applied to clothing, it is stable through several wash cycles. It is also suitable for treating sleeping bags, tents, and fabric used for insect screening. A liquid concentrate has been used to impregnate fabric for as long as the life of the garment. Permethrin is particularly helpful in the prevention of tick and chigger bites. These crawling arthropods must travel across the treated fabric, whereas flying insects tend to be attracted directly to exposed skin. The combination of a DEET-containing repellent and permethrin-treated clothing is generally highly ffective against a wide range of biting arthropods.

Crystalline Solid

ChEBI: A cyclopropanecarboxylate ester in which the esterifying alcohol is 3-phenoxybenzyl alcohol and the cyclopropane ring is substituted with a 2,2-dichlorovinyl group and with gem-dimethyl groups.

Pale brown liquid. Relatively water insoluble. Used as an insecticide.

The action of trichloroacetaldehyde and isobutene gives (I) (II) two trichloroenol isomers. The reaction is carried out at a low temperature using aluminum trichloride as a catalyst. In the presence of hydrogen chloride, acetonitrile interacts with absolute ethanol to form iminoether ether hydrochloride, which further reacts with absolute ethanol to generate triethyl orthoacetate (III). In the presence of catalyst p-toluenesulfonic acid, it is heated to 114-118°C and reacted for 3 hours to convert (I) to (II). The transposition product is reacted with triethyl orthoacetate, the catalyst is isobutyric acid, the reaction temperature is increased from 110℃ to 150℃, about 12h, the reaction is performed at 150～155℃ for 7～8h, and the pre-distillate is distilled off under the pressure of 0.08MPa, 3, 3-Dimethyl-4, 6, 6-trichlorohexene-[5]-acid ethyl ester (V) is accompanied by (VI). (VI) is subjected to a ring-opening reaction in a hydrogen chloride-ethanol solution to obtain (V). (V) In the presence of sodium ethoxide, react at 40～45℃ for 5h, cyclize to produce ethyl 2, 2-dimethyl-3-(2, 2-dichlorovinyl)-cyclopropanecarboxylate (VII) After rectification, ethyl permethrin is obtained with higher purity. In the presence of alkaline solution, (VII) was refluxed for 3 hours to saponify to obtain the corresponding sodium salt (VIII). (VIII) React with m-phenoxybenzyl triethylamine chloride to produce permethrin (IX). The reaction process is as follows: The synthesis of permethrin can be found in [5].

For the treatment of infestation with Sarcoptes scabiei (scabies).

Permethrin is a synthetic pyrethroid active against lice, ticks, mites, and fleas. It acts on neural cellmembranes, delaying repolarization and causing paralysis. The compound has no reported adverse properties, is heat and light stable, has 70% to 80% ovicidal activity, and leaves an active residue on the scalp. Permethrin is 26 times less toxic than lindane and 3 times less toxic than pyrethrins. A 1% permethrin cream rinse (Nix) preparation with a single application was determined to be more effective than treatment with RID. Permethrin-treated military uniforms are effective against human body lice. Apply the cream rinse for 10 minutes and rinse off with water. Localized pruritus may be reported with use of this product.

Labelled Permethrin (P288500). Synthetic pyrethroid insectide, more stable to light and at least as active as the natural pyrethrins and with low mammalian toxicity.