Structure-activity relationship insecticides

This paper reviews the discovery, the structure-activity relationships, insecticidal activity and biological properties of pyridalyl. 

Effects of Sesquiterpene Lactones on Seed Germination. Sesquiterpene lactones are common constituents of the Asteraceae but are also found in other angiosperm families and in certain liverworts (31,32). These highly bitter substances exhibit a wide spectrum of biological activities (J 3) which include cytotoxicity, anti-tumor, anti-microbial, insecticidal (34) and molluscicidal (35) properties. Furthermore, they are known causes for livestock poisoning and contact dermatitis in humans (33). Structure-activity relationship studies on sesquiterpene lactones have demonstrated that biological activity frequently depend on the presence of the cr... 

Sawicki RM, Denholm I, Famham AW, Murray AWA (1986) Structure-activity relationship to pyrethroid insecticides in houseflies (Musca domestica L.) with kdr and super-kdr. Sixth International Congress Pesticide Chemistry, Ottawa, Canada, Abstract 3E-25... 

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]. 

Choi JS, Soderlund DM (2006) Structure-activity relationships for the action of 11 pyrethroid insecticides on rat Nav1.8 sodium channels expressed in Xenopus oocytes. Toxicol Appl Pharmacol 211 233-244... 

However, the acctimulated Information on azadirachtin, while promising, is presently much less than that needed for insecticidal product commercialization (41). The mode of action, structure-activity relationships (SAR s), formulation, and metabolism of azadirachtin are not yet well understood. Furthermore, formulation studies are required prior to product development and commercialization. Consequently, further investigations are needed before the full potential of azadirachtin as an insect control agent or insecticide can be realized. 

Sieburth, S.McN., Langevine, C.N. and Dardaris, D.M. (1990) Organosilane insecticides. Part II. Chemistry and structure-activity relationships. Pestic. Sci., 28, 309-319. 

The well-known herbicide spike is prepared in high yield by heating in toluene a mixture of pivalic acid, JV-methylthiosemicarbazide, sulfuric acid and polyphosphoric acid to give (228 R = H), which on further treatment with methyl isocyanate yields (228 R = CONHMe) (81USP4283543). Other patented processes are known (76GEP2541115). Details on the structure-activity relationship of compounds in this class are available (70MI42700). A thiadiazole-containing insecticide is methidathion (229). 

In spite of the many studies on isolation, activity, and synthesis of natural antifeedants, the number of compounds commercially available remains low, often due to their cost of isolation, availability of the plant source, or low persistence in field conditions. To overcome these drawbacks, much research is conducted on structure—activity relationships (SAR). The rationale behind these studies is to discover the correlation between biological activity and chemical structure and to draw from that optimum structures having both the activity, stability, and selectivity for maximum feeding deterrence.4 5 SAR are much used in drug design6 and have been applied to insecticides.7... 

Prior to the advent of DDT and the organophosphates, the natural pyrethrins (32.33) found considerable use but were limited by their instability. The discovery of permethrin by Michael Elliot (3 4) proved a turning point for the new synthetic pyrethroids. Here were very active compounds that did not suffer from the stability problems of the natural compounds. And even now pyrethroid-like compounds continue to interest synthetic chemists due to their high insecticidal activity and relatively low mammalian toxicity. You would think that by now most of the very active compounds would have been found. but it seems that persistence and originality pay off. Workers at du Pont and FMC detail the structure-activity relationships for two groups of new pyrethroid-like compounds. Chemists at Dow reveal some of the intricacies in the synthesis of the cyclopropane carboxylate end of the molecule. 

The insecticidal activity and structure-activity relationships of novel pyrethroids prepared by reacting methyl phenyl substituted pyrazole methanols with dichloro chrysanthemic acid chloride are reported. These pyrethroids are active on tobacco budworm, fall armyworm, southern corn rootworm, and aster leafhopper, generally in the concentration range of 1000-250 ppm. Although less active than the pyrethroid standard bifenthrin, the overall structure-activity of these pyrazole pyrethroids with regard to substitution patterns is similar to that previously observed with bifenthrin analogs. 

The replacement of the 3-phenoxybenzyl alcohol fragment by 2-methyl[1,1 -biphenyl]-3-yl leads to an increase in initial and residual foliar activity in the alkyl aryl oxime ethers. An unanticipated result was the activity of these oxime ethers as soil insecticides. The corresponding 3-phenoxybenzyl alcohol oxime ethers were inactive as soil insecticides. The results of a structure activity relationship study revealed biological activity is enhanced by electron withdrawing substituents. 

Alkyl aryl methanone oxime ethers QSAR analysis, 183 insecticidal activity, 175-176 structure-activity relationships, 183-185 synthesis, 174-178... 

Organotins Insecticidal/Larvicidal Activities and Quantitative Structure-Activity Relationships... 

Bolboaca, S. and Jantschi, L. (2005a) Molecular descriptors family on structure—activity relationships. 2. Insecticidal activity of neonicotinoid compounds. Leonardo Journal of Sciences, 6, 78-85. 

The structure-insecticidal activity relationships of picrotoxinin analogs and related compounds have been studied by several researchers (3,16), who noted that the bridged bicyclic lactone skelton and the trans-isopropenyl or isopropyl group are essential for insecticidal activity. Structure-activity relationships of cyclodiene insecticides and BHC have also been thoroughly discussed (17-19). However, these discussions were published before the nature of the biological target site(s) for cyclodienes was known. 

In this equation, tt is the hydrophobic parameter, sc the Hancock steric parameter, and a the electronic constant for the bridgehead substituent. Median lethal dose is expressed as mol/fly. The bicy-clic phosphates have been shown to be mainly degraded by microsomal mixed-function oxidases in the housefly (12). Thus, the toxicity determined by injection after pb pretreatment is regarded as a good measure of the intrinsic toxicity of BPs, and it is probable that this equation reflects significant interactions between the bridgehead substituent of BPs and its site of action, i.e., a type of receptor. Little is known about the hypothetical BP receptor in the insect while a considerable amount of information has been obtained on a mammalian site. Three-dimensional receptor models have been proposed based on structure-activity relationships for BPs and related compounds (13,14). It is now important to substantiate the existence of the putative receptor in insects for the elucidation of the detailed mode of insecticidal action of BPEs. 

Hajjar, N.P. and Casida, J.E. 1978. Insecticidal benzoylphenyl ureas. Structure-activity relationships as chitin synthesis inhibitors. Science, 200, 1499-1500. 

Ozoe, Y., Yagi, K., Nakamura, M., Akamatsu, M., Miyake, T., and Matsumura, F. 2000. Fipronil-related heterocyclic compounds structure-activity relationships for interaction with gamma-aminobutyric acid- and voltage-gated ion channels and insecticidal action. Pest. Biochem. Physiol., 66, 92-104. 

In this chapter, a rationale of the structure-activity relationships of various series of bioactive secondary metabolites from Indo-Pacific marine invertebrates is reviewed. These include alkaloids, terpenes and polybrominated diphenyl ethers which were subjected to a series of bioassays in search for insecticidal, antibacterial, fungicidal, and cytotoxic lead compounds. From these various biotests, it was observed that the bioactivity of an analogue is not due to general toxicity but rather possesses a degree of specificity on a particular target biomolecule. The relationship between chemical structures and biological activity is related to the specific action of a compound. 

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