Benzyl chrysanthemates

Doherty, J.D., K. Nishimura, N. Kurihara, and T. Fujita. 1986. Quantitative structure-activity studies of substituted benzyl chrysanthemates. 9. Calcium uptake inhibition in crayfish nerve cord and lobster axon homogenates in vitro by synthetic pyrethroids. Pestic. Biochem. Physiol. 25 295-305. 

When less substituent positions are present STERIMOL can be used but in those cases there is often hardly any difference in results if compared with the MTD method. This is illustrated by our version of the QSAR of the insecticidal activity against American cockroaches of 36 substituted benzyl chrysanthemates. 

Figure 7. Standard used in Equation 20 to obtain MTD values in a series of benzyl chrysanthemates.

These results give some insight in the scope and limitations of the MTD, MTD and STERIMOL parameters. Let us first compare the MTD and MTD methods. In the example of the benzyl chrysanthemates the regression equations have only steric terms, sothat there is no difference between the two methods in principle. In the case of the benzoylphenyl ureas the intercorrelation between the MTD values and the other parameters is very low, so it is understandable that there is hardly any difference. But in the four other studies there was much more intercorrelation between the MTD values on the one hand and the electronic and/or hydrophobic parameters on the other hand, and in these cases the MTD method gives slightly better results. Our preliminary conclusion from the examples discussed, is that the MTD is the preferable one, both from fundamental and... 

In 1958, Barthel et al. [25] reported dimethrin (15), which was the first substituted benzyl alcohol ester of chrysanthemic acid. This compound was not put into practical use due to its low insecticidal activities. Phenothrin (16), one of the m-phenoxybenzyl alcohol esters developed by Fujimoto et al. [26], was found to have superior chemical stability as well as safety, and has been the sole pyrethroid used as a lice control agent for humans. Further improvement was made by Matsuo et al. [27] who introduced a cyano function at the a position of the benzyl part of phenothrin, leading to a-cyano-m-phenoxybenzyl alcohol esters (17). Thereafter, this alcohol moiety has been used as a component for a number of photostable pyrethroids for agricultural purposes however, the development of cross-resistance can be seen in some pests. 

Elliott M, Famham AW, Janes NF, Needham PH, Pearson BC (1967) 5-Benzyl-3-furylmethyl chrysanthemate, a new potent insecticide. Nature 213 493 194... 

The pyrethroids, a class of insecticides, are outstandingly safe to mammals and have been widely used against the household pest insects. A number of classical as well as recently developed synthetic analogs having high potency are esters of chrysanthemic acid with substituted benzyl alcohols. The principal target site of this... 

Pyrethroids from Chrysanthemic Acid, The unsaturated side chains of the allethrolone alcohol moieties of the natural pyrethrins are readily epoxidized by microsomal oxidases and converted to diols, thus detoxifying the insecticides. Esterification of chrysanthemic acid (9), R = CH3, with substituted benzyl alcohols produces useful insecticides barthrin [70-43-9], 2-chloro-3,4-methylenedioxybenzyl ( )-of,/ra/w-chrysanthemate, and dimethrin [70-38-2], 2,4-dimethylbenzyl ( )-og/rinsecticidal activity but are of very low mammalian toxicity, ie, rat oralLDBOs >20,000 mg/kg. 

BEP500 CAS 10453-86-8 HR 3 5-BENZYL-3-FURYL METHYL( )-cls,trans-CHRYSANTHEMATE... 

They are both chrysanthemic acid esters of (5-benzylfuran-3-yl)methanol (Elliott alcohol, 1) [15]. Patented methods [16] for the industrial preparation of Elliotf s alcohol are demanding or such as to be hardly exploited in industrial-scale plants. For instance, in one of these methods [17] (5-benzyl-3-furyl)methanol is obtained by a sequence of Claisen condensation of benzyl cyanide and a dialkyl succinate, hydrolysis, esterification, protection of the ketone group, formylation, cyclization to 5-benzyl-3-furfuryl ester and reduction to alcohol with lithium aluminium hydride. 

A more marked departure from the pyrethrin structure was represented by esters of chrysanthemic acid formed with substituted benzyl alcohols, such as... 

Photochemical decomposition of pyrethrins and synthetic analogues can be slowed down by the simultaneous use of antioxidants and photoscreens. In the course of decomposition, chrysanthemic acid, phenylacetic acid, benzyl alcohol, benzaldehyde and benzoic acid are formed from resmethrin (32) as decomposition products and, at the same time, the furan ring undergoes an oxidative transformation (Ueda et al., 1974) ... 

Figure 3). The first insecticidal derivatives, 6-halo-3,4-methylenedioxy-benzyl esters were reported in 1965 [2], but their insecticidal activities were not described in the paper. In the 1970 s, Ohno [3] and Elliott [4] reported their insecticidal esters. They reported that some norchrysanthemate esters showed comparable insecticidal activity to the corresponding chrysanthemates. However, further studies were discontinued at that time because they could not find any justification to develop these norchrysanthemic acid esters due to the difficulty of synthesizing norchrysanthemic acid. Despite this, we directed our attention to the norchrysanthemic acid esters because they had a lower molecular... 

Benzyl-3-furylmethyl (+)-cis-chrysanthemate (5-Benzyl-3-furyl)methyl(1R)-cis-chrysanthemate. See Cismethrin (5-Benzyl-3-furyl) methyl(1 R)-trans-chrysanthemate. See Bioresmethrin 5-Benzyl-3-furyl methyl ( )-cis,trans-... 

The same synthetic approach (i.e., varying the acid, alcohol, or both) resulted in the development of the coirnnercially successful active pyrethroid insecticides covered in this review this same approach also produced a host of relatively inactive isomers. The most potent constituent of resmethrin is the IR, 3R isomer (bioresmethrin), and is formed during the esterification of (-r) cis-, trans-chrysanthemic acid with 5-benzyl-3-furyImethyl alcohol to produce bioresmethrin and three other stereoisomers. Of greater interest to most chemists/biologists is the... 

Elliott M, Famham AW, Janes NF, Needham PH, Pearson BC (1967) 5-Benzyl-3-furylmethyl chrysanthemate a new potent insecticide. Nature (London) 213 493-494 Elliott M, Janes NF, Kinunel EC, Casida JE (1972) Metabolic fate of pyrethrin I, pyrethrin II, and allethrin administered orally to rats. J Agric Food Chtan 20 300-313... 

Miyamoto J, Nishida T, Ueda K (1971) Metabolic fate of resmethrin, 5-benzyl-3-furylmethyl A -trans chrysanthemate in the rat. Pestic Biochem Physiol 1 293-306 Miyamoto J, Suzuki T, Nakae C (1974) Metabolism of phenothrin (3-phenoxybenzyl A-trans-chrysanthemumate) in mammals. Pestic Biochem Physiol 4 438-450 Moss GP, Derden JC, Patel H, Cronin MT (2002) Quantitative structure-permeability relationships (QSPRs) for percutaneous absorption. Toxicol In Vitro 16 299-317 Mugeng J, Soderlund DM (1982) Liquid chromatographic determination and resolution of the enantiomers of the acid moieties of pyrethroid insecticides as their (-)-l-(l-phenyl)ethylamide derivatives. J Chromatogr A 248(1) 143-149... 

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