Pyrethroid insecticide

Fujimoto K, Itaya N, Okuno Y, Kadota T, Yamaguchi T (1973) A new insecticidal pyrethroid ester. Agric Biol Chem 37 2681-2682... 

Although structurally-diverse as evidenced above, the insecticidal pyrethroids still conform to a unique, operationally-defined, structure-activity relationship based on the physical characteristics and three-dimensional shape of the entire molecule conforming to those originally evidenced in the natural pyrethrins [13]. From this relationship, it becomes apparent that there is no single molecular aspect or reactive moiety that serves as a true toxophore for the pyrethroids and that their actions at target sites are dependent upon the entire stereospecific structure of these insecticides [1]. 

The newest class of insecticide, pyrethroids, is loosely based upon the naturally occurring pyrethrum derived from chrysanthemum flowers. Synthetic pyrethroids were developed in the 1980s but the naturally occurring pyrethrum was first commercially used in the 1800s. The chemical structure of pyrethroids is quite different from organochlorines and organophosphates, but the primary site of... 

Substances that can be metabolized to y-diketones, such as -hexane, which is metabolized to 2,5-hexanedione, cause the same disorders. Examples of the many other substances known to cause axonopathies are colchicine, disulhram, hydralazine, misonidazole, and insecticidal pyrethroids. Peripheral neuropathy is the most common kind of axonopathic disorder. However, other symptoms may be observed. Numerous cases of manic psychoses were produced in workers exposed to carbon disulfide, CS2, in the viscose rayon and vulcan rubber industries. 

Chemical Name A-a-cyano-3-phenoxybenzyl (lR,3R)-3-(2,2-dibromovinyl)-2,2-dimethyl cyclopropan-1-carboxylate CAS Registry No 52918-63-5 Uses insecticide (pyrethroid)... 

Cyclopentenones are important moieties present in many natural products such as ally-hethrone (45), which is an important component of insecticidal pyrethroid and an important intermediate for the synthesis of allethrolone and pyrethrins (Crombie et al., 1950 Berger et al., 1970 Cheng et al., 1982 Assereg et al., 1987). Commercial 5-nitro-1-pentene (42) has been chosen as the starting material for a new, improved synthetic approach for the preparation of allylrethrone, following two different ways (i) multi-step sequence and (ii) one-pot process as shown in Figure 2.13 (Ballini, 1993). 

Numerous examples of these two types of reaction are encountered in the field of the insecticidal pyrethroids. ... 

Figure 2.4 Example of a plant enzyme (Hydroxynitrilase from Hevea brasiliensis) used for the synthesis of an intermediate in the production process of an insecticide (pyrethroid) by DSM.Drawing by Dr. Guido Jach, Phytowelt GreenTechnologies GmbH.

Uses Insecticide pyrethroid synergist Manuf./Distrib. Supelco http //www.sigma-aldrich.com... 

The final example of a dendrogram to be shown here, Fig. 5.10, is also one of the largest. This figure shows one thousand conformations of an insecticidal pyrethroid analogue (see Fig. 5.5) described by the values of four torsion angles (Hudson et al. 1992). A dendrogram such as this was used for the selection of representative conformations from the one thousand conformations produced by molecular dynamics simulation. 

Synthetic analogs of the pyrethrins, pyrethroids, have been widely produced as insecticides during recent years. The first of these was allethrin, and another common example is fenvalerate (see structural formulas in Figure 4.6). Other examples of insecticidal pyrethroids that have water pollution potential include cypermethrin and deltamethrin. Because of the ways that they are applied and their biodegradabilities, these substances generally are not found to be significant water pollutants. 

Fujikawa M, Nakao K, Shimizu R, Akamatsu M (2007) QSAR study on permeability of hydro-phobic compounds with artificial membranes. Bioorg Med Chem 15 3756-3767 Fujimoto K, Itaya N, Okuno Y, Kadota T, Yamaguchi T (1973) A new insecticidal pyrethroid ester. Agric Biol Chem 37 2681-2682... 

Several ingenious syntheses of the dichloro-analogue (15) of chrysanthemic acid, used in the formation of the new generation of insecticidal pyrethroids [e.g. cypermethrin (16)] have been published in the past few years. To add to this list are new methods based on the Favorski rearrangement and on an intramolecular carbene insertion reaction, and a further method based on the Wittig reaction. ... 

A Michael reaction coupled with aldol-type condensation has been used in the one-pot synthesis of allylrethrone (Scheme 7.7), an important component of an insecticidal pyrethroid [32]. The conjugative addition of 5-nitro-l-pentene to methyl vinyl ketone is catalyzed by AI2O3 and occurs in the absence of solvent. An intramolecular aldol-type condensation is then carried out in alkaline aqueous medium after the conversion of the nitro group into a carbonyl by the Nef reaction. 

Pyrethroids, the natural insecticides. The insecticides "pyrethroids , naturally occurring in Pyrethrum species, are the esters in which the acidic part is the cyclopentenone fatty acid, structurally similar to jasmonate ... 

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