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1.
The synthesis of a series of mono- and disubstituted biphenyl-3-ylmethyl esters of 3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylic acid is described. The bioactivity of these compounds against Spodoptera eridania, Epilachna varivestis, Oncopeltus fasciatus, Acrythosiphon pisum and Tetranychus urticae is presented and discussed. Substitution of fluorine, chlorine and methyl groups in the 2-position of the biphenyl ring generally led to an increase in activity over the unsubstituted parent biphenyl ester. In addition, pyrethroid esters derived from these 2-substituted biphenyl-3-ylmethanols appeared to have a broader spectrum of activity than ‘classical’ pyrethroids. For example, the (1RS)-cis-3-(2,2-dichlorovinyl)-2, 2-dimethylcyclopro-panecarboxylic acid ester of 2-methylbiphenyl-3-ylmethanol was acaricidal, while maintaining a level of activity against other insects that was equal to or greater than cis-permethiin. Biological data on other esters of this novel alcohol are also presented.  相似文献   

2.
A study has been made of the effects of bioallethrin, RU-15525 [5-benzyl-3-furylmethyl (1R)-cis-2,2-dimethyl-3-(tetrahydro-2-oxo-3-thienylidenemethyl)-cyclopropanecarboxylate, ‘Kadethrin’], and deltamethrin on the electrical activity, measured in vivo, of a cuticular mechanoreceptor of Periplaneta americana. The modifications induced by these pyrethroids on the membrane excitability can be classified into two groups: Type I effects (bioallethrin) are characterised by a substantial increase in the number of action potentials triggered at the initiation site by a given mechanical stimulation, by an electrical activity persisting after mechanical stimulus has been stopped (repetitive activity), and possibly, by an inhibition of excitability of the cell membrane. Type II effects (RU-15525 and deltamethrin), are characterised by an inhibition of the excitability of the initiation site. In the case of RU-15525, there was a transient spontaneous electrical activity. Both types of effects have been linked to an action on the sodium channel, particularly at the initiation site. The preparation studied, which possessed no synapses, was shown to be more sensitive to deltamethrin (which is also the most insecticidal of the three pyrethroids) than to either allethrin or RU-15525. These results suggest that it is unnecessary to envisage a main target (sodium channel) that is different for the two types of pyrethroid.  相似文献   

3.
A summary is given of the results of three sets of electrophysiological experiments on the American cockroach (Periplaneta americana). The effects of DDT and S-bioallethrin [bioallethrin (S)-cyclopentenyl isomer] on single giant axons were studied using the voltage-clamp technique. Whereas both molecules induced long tails of inward (sodium ion) current, the voltage and time-dependency of these tails differed. With DDT, the tail was proportional to the activation of the peak current and decreased with the duration of the pulse, suggesting that the molecules were bound to open sodium channels and delayed their closing. With S-bioallethrin, the voltage dependency of the tail was different from that of the peak current, and the tail current increased exponentially with the duration of the depolarisation, suggesting that the pyrethroid insecticide modified resting (or silent) sodium channels into slowly activating channels. Modified action potentials, mimicking those produced by the two molecules, were computed on the basis of these results. Deltamethrin, one of the most potent pyrethroid insecticides, was applied topically on a leg mechanoreceptor and was found to have little effect on the local ‘receptor potential’ but to inhibit action potential production. The effects of topical applications of deltamethrin on the dorsal part of the abdomen, on nervous activity in the abdominal connectives, were studied under different experimental conditions. The results suggest that the insecticide molecules diffused rapidly through the cuticle, were concentrated in the haemolymph, and eventually reached the central nervous system, where they inhibited nerve activity.  相似文献   

4.
Metabolism in mice of the separated cis- and trans-isomers of the pyrethroid insecticide cypermethrin (NRDC 149), (RS)-α-cyano-3-phenoxybenzyl (1RS)-cis, trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylate, was investigated in each case with preparations that were 14C-labelled in the benzyl and cyclopropyl moieties. Radioactivity from the trans-isomer was mainly excreted in the urine and that from the cis-isomer in the faeces. Elimination of both isomers was rapid except for a small portion (approximately 2%) of the cis-isomer which was released from the fat with a half-life of approximately 13 days. Metabolism of cypermethrin occurred mainly by ester cleavage and elimination of the cis- and trans-3-(2,2-dichlorovinyl)-2,2-dimethyl- cyclopropanecarboxylic acid moieties as glucuronide conjugates. The α-cyano-3-phenoxybenzyl alcohol released by ester cleavage was mainly converted to 3-phenoxy-benzoic acid which was partly eliminated unchanged, partly conjugated with aminoacids (mainly taurine) and glucuronic acid, and partly oxidised to 3-(4-hydroxyphenoxy) benzoic acid which was excreted as the sulphate conjugate. Metabolites retaining the ester linkage were formed by hydroxylation at various sites in the molecule with more hydroxylation of the cis- than of the trans-isomer occurring.  相似文献   

5.
The synthesis of (1RS)-cis,trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylic acid by dehydrohalogenation of 4,6,6,6-tetrahalohexanoates has been modified to produce stereo-selectively the cis-isomer. A new stereospecific synthesis of cis-3-(2,2-dihalovinyl)-2,2-dimethylcyclopropanecarboxylic acids using a bicyclic lactone and its extension to the preparation of the optically active (1R)-cis acid are described.  相似文献   

6.
Preparation of 3-phenoxybenzyl chrysanthemates and their dihalovinyl analogues substituted with a cyano group at the 2-, 6-, (R)-α-, or (S)-α- positions is described. The (R)- and (S)- isomers of α-cyano-3-phenoxybenzyl esters of 2,2-difluoro-, -dichloro-, and -dibromo-vinyl analogues of cis- and trans- chrysanthemic acid are separated chromatographically, as are the separate pairs of enantiomers of fenvalerate, (RS)-α- cyano-3-phenoxybenzyl (RS)-2-(4-chlorophenyl)-3-methylbutyrate. An optically active ester of α-cyano-3-phenoxybenzyl alcohol (obtained using D -oxynitrilase) with 2,2,3,3-tetramethylcyclopropanecarboxylic acid is synthesised.  相似文献   

7.
The effects of pyrethroids were studied upon isolated segmental nerves and neuromuscular junctions in both susceptible (Cooper) and knockdown-resistant (kdr; super-kdr) strains of housefly larvae (Musca domestica L.). Isolated segmental nerves contained neither cell bodies nor synaptic contacts; thus, any effects of pyrethroids were attributed solely to their actions upon voltage-dependent Na+ channels. Threshold concentrations of the type II pyrethroid, deltamethrin, required to elevate the spontaneous firing rate of these nerves were determined. Both resistant strains were about ten times less sensitive to deltamethrin than the susceptible strain, but insensitivity of super-kdr nerves was no greater than in the less resistant kdr strain. At neuromuscular junctions, the minimum concentrations of pyrethroids needed to trigger massive increases in the frequency of miniature excitatory postsynaptic potentials (mEPSPs) were determined for deltamethrin and the type I pyrethroid, fenfluthrin. With fenfluthrin there was no detectable difference between the junctions of kdr and super-kdr strains, which were both about ten-fold less sensitive than Cooper junctions. With deltamethrin, kdr junctions were about 30 times less sensitive than those of Cooper; super-kdr junctions were dramatically insensitive to deltamethrin, being some 10000- and 300-fold less sensitive than those of Cooper and kdr respectively. Thus, in the synaptic assay, super-kdr conferred an extension in resistance over kdr only against the type II pyrethroid, it being ineffective against fenfluthrin. We suggest that kdr resistance comprises at least two site-insensitive areas within the nervous system. One involves insensitivity of the Na+ channel and has similar efficacy in both kdr and super-kdr strains against type I and II pyrethroids; the other is associated with the presynaptic terminal and is particularly effective in super-kdr resistance against type II pyrethroids. The latter could be associated with Ca2+-activated phosphorylation of proteins involved with neurotransmitter release. Such phosphorylation reactions are known to be perturbed by pyrethroids, especially by type II compounds.  相似文献   

8.
The potency of six dietary pyrethroids, as toxicants and inhibitors of weight gain in first- and fourth-instar Tribolium castaneum (Herbst) larvae, decreased in the order of cis-cypermethrin and deltamethrin > trans-cypermethrin and cis-permethrin > fenvalerate and trans-permethrin. Dosages that reduced larval weight also delayed pupation and emergence, probably due to their antifeeding activity. Three oxidase inhibitors (piperonyl butoxide, O, O-diethyl O-phenyl phosphorothioate, and O-isobutyl O-prop-2-ynyl phenylphosphonate), at a dietary concentration of 100 mg kg?1, had little or no effect on the toxicity of trans-permethrin, but strongly synergised the toxicity of cis-cypermethrin by about 3-, 3- and 10-fold, respectively. Piperonyl butoxide also synergised the toxicity of cis-permethrin, trans-cypermethrin and deltamethrin, but not that of fenvalerate. On the other hand, an esterase inhibitor, profenofos, did not enhance the potency of any of the α-cyano-3-phenoxybenzyl pyrethroids. Oxidases appear to be more important than esterases in pyrethroid detoxification by T. castaneum larvae.  相似文献   

9.
BACKGROUND: Pyrethroids are among the most potent pesticides known, with great potential for structural variation with retention or enhancement of potency. The simple methyl ester is easier to prepare (at least one step shorter) than the more complex pyrethroids modified on the alcohol moiety. The objective was to synthesise methyl esters of pyrethroid acids containing an aromatic ring on the acid moiety and evaluate their biological activity against Ascia monuste orseis Latr., Tuta absoluta Meyrick, Periplaneta americana (L.), Musca domestica L. and Sitophilus zeamais (Motsch.). RESULTS: The synthetic sequence required seven steps: protection of the hydroxyl groups of D ‐mannitol, diol oxidative cleavage with sodium metaperiodate, alkene formation by Wittig reaction with methoxycarbonylmethylidene(triphenyl)phosphorane, cyclopropanation, acetal hydrolysis with perchloric acid and oxidative cleavage with sodium metaperiodate gave methyl (1S, 3S)‐3‐formyl‐2,2‐dimethylcyclopropane‐1‐carboxylate. The final step comprised reaction of the aldehyde with five different aromatic phosphorus ylides to give the pyrethroids. CONCLUSION: An efficient and versatile synthesis of ten new pyrethroid methyl esters has been accomplished from the readily available D ‐mannitol in seven steps. All compounds showed insecticidal activity, and methyl (1S, 3S)‐3‐[(Z)‐2‐(4‐chlorophenyl)vinyl]‐2,2‐dimethylcyclopropane‐1‐carboxylate was the most active, killing 90% of A. monuste orseis and 100% of T. absoluta and P. americana. Copyright © 2009 Society of Chemical Industry  相似文献   

10.
Electrophysiological techniques were used to analyse the effects, on the activity in the sensory nerves of Periplaneta americana and Blabera craniifer, after topical applications of three different pyrethroid insecticides: deltamethrin, (1R)-tetramethrin, and 5-benzyl-3-furylmethyl (E)-(1R)-cis-2,2-dimethyl-3-(2-oxothiolan-3-ylidenemethyl)cyclopropanecarboxylate (RU-15525; ‘Kadethrin’). The insecticides were applied: (a) to the cercus, and the activity was recorded on the cercal nerve and on the central nervous connectives; or (b) to the last segments of the metathoracic leg, and the corresponding activity was recorded on the crural nerve. In both cases, several categories of receptor were affected but the major part of the recorded activity came from the mechanoreceptors, the functional properties of which were monitored throughout the experiments. In most cases, topical application of small amounts of pyrethroid were found to induce an increase in the spontaneous activity, followed by decrease in excitability. Characteristic differences were, however, found between the three compounds and the effects were concentration- and solvent-dependent. The results were consistent with those obtained from experiments on the sense organs of vertebrates but did not support the idea that the effectiveness of pyrethroid insecticides with an α-cyanobenzyl group, compared with those without an α-cyanobenzyl group, originates from a greater effect on the peripheral sensory receptors.  相似文献   

11.
Strains of Culex quinquefasciatus Say, selected with biopermethrin [(1R)-trans-permethrin] or with (1R)-cis-permethrin, were examined in the larval stage for crossresistance to 30 pyrethroids, DDT, dieldrin, temephos, propoxur, and two organotin compounds. The (1R)-trans-Permethrin-R strain [resistance factor (RF) = 4100-fold] and the (1R)-cis-Permethrin-R strain (RF= 450-fold) of C. quinquefasciutus were cross-resistant to all pyrethroids tested [RF= 12-fold for an allethrin isomer to about 6000-fold for (RS,RS)-fenvalerate] as well as to DDT (RF= about 2000-fold). However, they were not significantly Cross-resistant to dieldrin, temephos, propoxur, and the two organotin compounds. Changes in the alcohol moiety, structural isomerism, and susceptibility of the cyclopropane C-3 side chain to oxidative attack are important factors in determining the level of cross-resistance to various pyrethroids. Limited synergism of the pyrethroids by S,S,S-tributyl phosphorotrithioate and piperonyl butoxide (PB), and of DDT by chlorfenethol and PB, suggested that some non-metabolic mechanism, such as kdr, may be an important component of resistance to pyrethroids as well as to DDT in this mosquito.  相似文献   

12.
Bromination of the dichlorovinyl group of cypermethrin yielded a new compound which is a highly potent insecticide. This dibromo adduct has four asymmetric centres and therefore can exist as a mixture of 16 stereoisomers. To establish the influence of the absolute configuration at the chiral centres on the biological activities of these isomers, each of the isomers was isolated; their insecticidal activities against larvae of Heliothis virescens, and adult Calliphora erythrocephala and Blattella germanica were then determined and compared with those of (S)-α-cyano-3-phenoxybenzyl (1R)-cis-3-(2,2-dibromovinyl)-2,2-dimethylcyclopropanecarboxylate (deltamethrin NRDC 161), of fenvalerate, and of the eight stereoisomers of cyper methrin.  相似文献   

13.
The knockdown and contact killing actions of various pyrethroids were compared using Blattella germanica and Periplaneta americana. A wide range of knockdown activity was found; 5-benzyl-3-furylmethyl (1R)-cis-3-(dihydro-2-oxo-3-thienylidenemethyl)-2,2-dimethylcyclopropanecarboxylate (RU 15525) acted fastest, more rapidly than pyrethrins, against B. germanica as well as having a low LD50 value. Topical application and direct spray tests showed that (S)-α-cyano-3-phenoxybenzyl (1R)-cir-3-(2,2-dibromovinyl)-2,2-dimethylcyclopropanecarboxylate (NRDC 161) was more active as a killing agent, by an order of magnitude, than cismethrin, the next most active compound, and also had considerable knockdown activity. Piperonyl butoxide generally had little synergist effect. Female P. americana were over three times more tolerant than males to a range of insecticides applied topically. Residual knockdown action in the WHO resistance test was observed to provide baseline data. There was little overlap in speed of action between pyrethroids and other insecticides among the compounds tested.  相似文献   

14.
The response of susceptible (S), moderately resistant (R1) and strongly resistant (R2) peach-potato aphids, Myzus persicae (Sulz.) to organophosphorus, carbamate and pyrethroid insecticides was tested by a leaf-dip bioassay. The aphids were placed on potato leaves (dipped in insecticide solutions 1–2 or 24 h before infestation) and their mortality examined 48 h later. R1 aphids were virtually susceptible to most of the carbamates, demephion and acephate, but were slightly to moderately resistant (2.1–9.4 times) to permethrin, cypermethrin and (S)-α-cyano-3-phenoxybenzyl (1R)-cis-3-(2,2-dibromovinyl)-2,2-dimethylcyclopropanecarboxylate (I), (NRDC 161), to 5,6,7,8-tetrahydro-2-methylquinolin-4-yl dimethylcarbamate (II), (Hoechst 25 682) and demeton-S-methyl. R2 aphids resisted more strongly or very strongly (between 65 and 1280 times) the pyrethroids, demeton-S-methyl (×94), II (×83) and demephion (×9), and were slightly to moderately (2–5 times) resistant to acephate, pirimicarb, ethiofencarb and 2-(dimethylcarbamoyloxyimino)-3-methoxyimino-N,N- dimethylbutyramide (III), (DPX 3853). Both resistant strains were susceptible to nitrilacarb [4,4-dimethyl-5-(methylcarbamoyloxyimino)pentanenitrile] complex (1:1) with zinc chloride (IV), (AC 85 258). The implications of these results in terms of practical aphid control are discussed.  相似文献   

15.
Adult Rana pipiens pipiens (Shreber) are highly sensitive to insecticidal α-cyano-3-phenoxybenzyl esters administered subcutaneously, i.e., LD50 0.13–0.35 mg/kg for deltamethrin and the most potent isomer of each of cis-cypermethrin, fenpropathrin, and fenvalerate and 0.65 mg/kg for (1R,αS)-trans-cypermethrin. Pyrethroids lacking the α-cyano substituent [pyrethrins, S-bioallethrin, kadethrin, and the Cis- and trans-isomers of (1R)-tetramethrin, (1RS)-resmethrin, (1R)-phenothrin, and (1R)-permethrin] vary greatly in their toxicity (LD50 0.14 to > 60 mg/kg) and the trans isomers are much less toxic than the corresponding cis isomers. The trans/cis specificity is due in large part to relative detoxification rates based on synergism studies with the resmethrin and permèthrin isomers and liver pyrethroid esterase assays with the permethrin and cypermethrin isomers. Poisoning by the noncyano compounds involves hyperactivity and tremors whereas by the cyanophenoxybenzyl esters involves tonic seizures and choreoathetosis, i.e., types I and II syndromes, respectively. Picrotoxinin, t-butylbicyclophosphate, and five other small cage compounds give a third type of syndrome with clonic seizures. Diazepam and its 2′-fluoro-4-methyl-4,5-dihydro analog (RO 5-3636) are more effective than 23 other compounds tested in protecting against deltamethrin toxicity. Diazepam is most effective in alleviating the Type II syndrome, intermediate with the type I syndrome, and is not active with picrotoxinin.  相似文献   

16.
The insecticidal activities to Musca domestica L. and Phaedon cochleariae Fab. of a series of 3-phenoxybenzyl pyrethroid esters with a cyano substituent at the 2-, 6-. (R)-α-, or (S)-α-position are compared with those of the unsubstituted analogues. Only an (S)-α-substituent enhances activity; others diminish or almost eliminate it. (RS)-α-mixtures are generally less active than would be predicted from the potencies of their separate constituents.  相似文献   

17.
Sugar beet, wheat, lettuce and cotton were grown in soil treated with [14C]permethrin, the crops being sown at intervals of 30, 60 and 120 days after treatment of the soil. The uptake of radioactive residues into these crops was measured. Low radioactive residues (up to 0.86 μg g?1) were detected in the mature plants sown 30 days after soil treatment, and this uptake declined significantly as the interval between soil treatment and sowing increased. Metabolites derived from the acid moiety of the permethrin molecule were shown to constitute the greater part of the residue transferring from the soil to the crops. (1RS)-cis- and (1RS)-trans-3-(2,2-dichlorovinyl)- 2,2-dimethylcyclopropanecarboxylic acid and 3-(2,2-dichlorovinyl)-1-methylcyclopropane-1,2-dicarboxylic acid were identified as the major acidic metabolites. The latter compound is a metabolite of permethrin which has not previously been identified in soil or plants.  相似文献   

18.
New pyrethroids containing heterocyclic rings in the alcohol moieties were synthesised and their insecticidal activities were studied. Of these new pyrethroids, 3-benzylpyrrol-1-ylmethyl (1RS-cis, trans-3(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylate was found to be the most effective, having higher activity than permethrin against Musca domestica by a topical application method. In addition, para-substituted analogues of the 3-benzylpyrrol-1-ylmethyl ester were also synthesised to study the substituent effects on insecticidal activities; the residual effects of these compounds against Blattella germanica were also examined.  相似文献   

19.
Deltamethrin and NRDC 157, pyrethroid insecticides that produce different poisoning syndromes in mammals, enhanced veratridine-dependent, sodium channel-mediated 22Na+ uptake in mouse brain synaptosomes. Concentrations producing half-maximal enhancement were 2.5 × 10?8M (deltamethrin) and 2.2 × 10?7M (NRDC 157). This effect was stereospecific: The nontoxic 1S enantiomers had no significant effect on veratridine-dependent activation. At high deltamethrin concentrations, enhancement was maximal at 5 × 10?5?1 × 10?4M veratridine. Pyrethroid enhancement was completely blocked by 5 × 10?6M tetrodotoxin, and neither pyrethroid affected 22Na+ uptake in the absence of veratridine at concentrations up to 1 × 10?5M. The relative potencies of deltamethrin and NRDC 157 in the synaptosomal sodium channel assay agree well with their relative acute toxicities to mice when administered by intracerebral injection. These findings demonstrate that pyrethroids exemplifying both characteristic poisoning syndromes are potent, stereospecific modifiers of sodium channel function in mammalian brain.  相似文献   

20.
In May 2001 a sample of Culex pipiens pipiens variety molestus Forskål from Marin County, California, collected as larvae and reared to adults, was found to show reduced resmethrin and permethrin knock‐down responses in bottle bioassays relative to a standard susceptible Cx pipiens quinquefasciatus Say colony (CQ1). Larval susceptibility tests, using CQ1 as standard susceptible, indicated that the Marin mosquitoes had LC50 resistance ratios of 18.3 for permethrin, 12 for deltamethrin and 3.3 for pyrethrum. A colony of Marin was established and rapidly developed higher levels of resistance in a few generations after exposure to permethrin as larvae. These selected larvae were shown to cross‐resist to lambda‐cyhalothrin as well as to DDT. However, adult knock‐down time in the presence of permethrin, resmethrin and pyrethrum was not increased after increase in tolerance to pyrethroids as larvae. Partial and almost complete reversion to susceptibility as larvae was achieved with S, S, S‐tributylphosphorotrithioate and piperonyl butoxide (PBO), respectively, suggesting the presence of carboxylesterase and P450 monooxygenase mediated resistance. Insensitive target site resistance (kdr) was also detected in some Marin mosquitoes by use of an existing PCR‐based diagnostic assay designed for Cx p pipiens L mosquitoes. Carboxylesterase mediated resistance was supported by use of newly synthesized novel pyrethroid‐selective substrates in activity assays. Bottle bioassays gave underestimates of the levels of tolerance to pyrethroids of Marin mosquitoes when compared with mortality rates in field trials using registered pyrethroid adulticides with and without PBO. This study represents the first report of resistance to pyrethroids in a feral population of a mosquito species in the USA. Copyright © 2003 Society of Chemical Industry  相似文献   

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