The metabolic pathways for the breakdown of the pyrethroids vary little between mammalian species but vary somewhat with structure. ... Essentially, pyrethrum and allethrin are broken down mainly by oxidation of the isobutenyl side chain of the acid moiety and of the unsaturated side chain of the alcohol moiety with ester hydrolysis playing and important part, whereas for the other pyrethroids ester hydrolysis predominates. /Pyrethrum and pyrethroids/
Initially, it was suggested that decomp of pyrethrins was caused by hydrolytic enzymes. Subsequent studies have shown that lipases of roaches & houseflies readily hydrolyze pyrethrin esters to keto alcohols, chyrsanthemum acids, & several unidentified compounds ... Some 8-12% of labeled pyrethrin applied to roaches was excreted as (14)CO2. When applied to houseflies, no (14)CO2 was detected. ... Chrysanthemum acid & 5 unknown metabolites were detected. Three of unknown metabolites had intact chrysanthemum acid moiety & an ester linkage. ... It appears that initial degradation occurred on pyrethrolone or cinerolone moiety. /Pyrethrins/
Following ingestion, pyrethrins are hydrolysed by various digestive enzymes in the gastro-intestinal tract. However, a small portion of the insecticidally active compounds or its derivatives are absorbed, as shown by their toxicity and their effect on the liver. Pyrethrins may also be absorbed following inhalation or dermal contact. They are rapidly distributed to most tissues, particularly to those with a high lipid content, and are concentrated in central and peripheral nervous tissues. Pyrethrins or their metabolites are not known to be stored in the body or to be excreted in the milk, but no study of the matter has employed modern methods. The major metabolic pathways for pyrethrins are hydrolysis of the central ester bond, oxidative attacks at several sites, and conjugation reactions, to produce a complex array of primary and secondary water-soluble metabolites that undergo urinary excretion. Metabolism is believed to involve nonspecific microsomal carboxyesterases and microsomal mixed function oxidases, which are located in nearly all tissue types, with particularly high activities in the liver. Metabolites, such as chrysanthemummonocarboxylic acid, are excreted in the urine and faeces. (L857, L889)
Pyrethrins exert their effect by prolonging the open phase of the sodium channel gates when a nerve cell is excited. They appear to bind to the membrane lipid phase in the immediate vicinity of the sodium channel, thus modifying the channel kinetics. This blocks the closing of the sodium gates in the nerves, and thus prolongs the return of the membrane potential to its resting state. The repetitive (sensory, motor) neuronal discharge and a prolonged negative afterpotential produces effects quite similar to those produced by DDT, leading to hyperactivity of the nervous system which can result in paralysis and/or death. (L857, A560)
来源:Toxin and Toxin Target Database (T3DB)
毒理性
致癌物分类
对人类不具有致癌性（未被国际癌症研究机构IARC列名）。
No indication of carcinogenicity to humans (not listed by IARC).
Pyrethrin effects typically include rapid onset of aggressive behavior and increased sensitivity to external stimuli, followed by fine tremor, prostration with coarse whole body tremor, elevated body temperature, coma, and death. Paresthesia, severe corneal damage, hypotension and tachycardia, associated with anaphylaxis, can also occur following pyrethrin poisoning. (L857)
The clinical manifestations of inhalation exposure to pyrethrins can be local or systemic. Localized reactions confined to the upper respiratory tract include rhinitis, sneezing, scratchy throat, oral mucosal edema, and even laryngeal mucosal edema. Localized reactions of the lower respiratory tract include cough, shortness of breath, wheezing, and chest pain. An asthmalike reaction occurs with acute exposures in sensitized patients. Hypersensitivity pneumonitis characterized by chest pain, cough, dyspnea, and bronchospasm may occur in an individual chronically exposed. Large amounts may cause nausea, vomiting, tinnitus, headache, and other central nervous system disturbances. (A566)
Pyrethrins are absorbed through intact skin when applied topically. When animals were exposed to aerosols of pyrethrins with piperonyl butoxide being released into the air, little or none of the combination was systemically absorbed. /Pyrethrins/
Compounds of formula I
wherein the substituents are as defined in claim 1, and the agrochemically acceptable salts and all stereoisomers and tautomeric forms of the compounds of formula I can be used as insecticides and can be prepared in a manner known per se.
Molecules having pesticidal utility, and intermediates, compositions, and processes, related thereto
申请人：Dow AgroSciences LLC
公开号：US20180279612A1
公开（公告）日：2018-10-04
This disclosure relates to the field of molecules having pesticidal utility against pests in Phyla Arthropoda, Mollusca, and Nematoda, processes to produce such molecules, intermediates used in such processes, pesticidal compositions containing such molecules, and processes of using such pesticidal compositions against such pests. These pesticidal compositions may be used, for example, as acaricides, insecticides, miticides, molluscicides, and nematicides. This document discloses molecules having the following formula (“Formula One”).
