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1.
N-Arylcarbamoylpyrazolines with various substituents at the para position of the carbamoyl benzene ring inhibited ATP-dependent Ca2+-uptake in synaptosomes prepared from the rat brain. The activity of these compounds was evaluated as log(1/I50), the reciprocal logarithm of half inhibitory concentration, I50 (m ), from the concentration–response curve for the inhibition of Ca2+-uptake. Among the compounds tested, methyl 3-(4-chlorophenyl)-4-methyl-1-[N-(4-trifluoromethylphenyl)carbamoyl]-2-pyrazoline-4-carboxylate was the most potent, the I50 value of which as 9·12×10−7 m . Variations in the activity in terms of log(1/I50) were quantitatively analysed using a substituent parameter, showing that the higher the electron-withdrawing effect of the substituent, the higher was the activity. The substituent effects were similar to those on insecticidal activity against the Americal cockroach. The higher the inhibitory activity against Ca2+ uptake, the higher seemed to be the insecticidal activity. Methyl(4S) - 3 - (4 - chlorophenyl) - 4 - methyl - 1 - [N - (4 - chlorophenyl)carbamoyl] - 2 - pyrazoline -4-carboxylate had higher inhibitory activity against Ca2+-uptake and higher in-secticidal activity than the R-isomer, but the difference was greater in theCa2+-uptake system.  相似文献   

2.
The quantitative relationship between the structure of optically active 4-substituted 2-methoxy-1,3,2-oxazaphospholidine 2-sulfides (4-RMOS) and their insecticidal activity on the house fly, Musca domestica L., was analysed using reported physicochemical parameters and regression analysis. The configuration at the C4 atom was more important for insecticidal activity than that at the phosphorus atom, since the coefficient of the dummy parameter for the C4- configuration was larger than that for the configuration of the phosphorus atom: (S)c(R)p diastereoisomers showed the highest insecticidal activity, and the activity decreased in the order of (S)c(R)p > (S)c(S)p > (R)c(R)p > (R)c(S)p. The electronic nature of the substituent at the C4 position was the most important, followed by the steric and hydrophobic effects: the more electron-donating, the less bulky and the more hydrophobic the 4-substituent, the higher the insecticidal activity. Thus the highest activity was obtained for the isopropyl derivatives, and the activity decreased in the order of isopropyl > isobutyl > ethyl > sec-butyl > benzyl > phenyl > methyl > tert-butyl.  相似文献   

3.
The metabolism of the pyrethroid insecticide fenvalerate [(RS)-α-cyano-3-phenoxybenzyl (RS)-2-(4-chlorophenyl)-3-methylbutyrate] ( I ), and of its most insecticidal (αS,2S) isomer ( II ), has been examined in cabbage plants grown and treated under laboratory conditions with [14C]chlorophenyl- and [ring-14C]benzyllabelled preparations of the two compounds. Both insecticides disappeared from the treated leaves with similar half-lives of approximately 12–14 days; they underwent ester cleavage to a significant extent, together with some hydroxylation at the 2- or 4-position of the phenoxy ring, and hydrolysis of the nitrile group to amide and carboxyl groups. Most of the carboxylic acids and phenols thus produced occurred as glycoside conjugates. In separate experiments, the uptake and metabolism of 2-(4-chlorophenyl)-3-methylbutyric acid ( X ), the acidic half of the molecule, were examined in the laboratory, using abscised leaves of kidney bean, cabbage, cotton, cucumber and tomato plants. The acid X was found to be readily converted, mainly into glucose and 6-O-malonylglucose esters in kidney bean, cabbage and cucumber plants, into glucosylxylose, sophorose and gentiobiose esters in cotton, and into two types of triglucose esters with differing isomerism in tomato. One of the acetyl derivatives of the trisaccharide conjugates was identical with the synthetic deca-acetyl derivative of the [1 → 6]-triglucose ester.  相似文献   

4.
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   

5.
The insecticidal activities of optical isomers of 3-phenoxybenzyl 1-(4-ethoxyphenyl)-2,2-dichlorocyclopropanecarboxylate and related compounds were measured with American cockroaches and their knockdown activities were evaluated with house flies. The activities of the S(?)-isomer of the dichlorocyclopropanecarboxylate were higher than those of the R(+)-isomer. The effects of the compounds on the inward membrane currents induced by a stepdepolarizing pulse in crayfish axonal membranes were examined under voltage clamp conditions by the sucrose gap method. The compounds induced a tail current upon step repolarization of the membrane. The tail current decayed to zero in each record, but developed with time after the start of application of the compound until a steady level was reached. The rate of decay of the tail current observed in axonal membranes treated with the S(?)-isomer was slower than with the R(+)-isomer. The rates of development of the tail current induced by the two isomers were not very different.  相似文献   

6.
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   

7.
An esterase, that has been partially purified from oat tissues, catalyses the hydrolysis of the wild oat herbicide benzoylprop-ethyl and of the related esters of N-benzoyl-N-(3-chloro-4-fluorophenyl)-DL -alanine, including flamprop-methyl and flampropisopropyl. The enzyme is virtually stereospecific for the L -isomers in the racemic mixtures. Hydrolysis of flamprop-methyl in oat tissues shows similar enantiomeric discrimination, but the ethyl and isopropyl ester analogues are converted in vivo to the free acid with very little overall stereoselectivity. Oat tissues must, therefore, contain another enzyme, labile to isolation, that acts on the D -isomers of the higher esters. This was confirmed by showing that it is possible to manipulate the stereoselectivity of the de-esterification of the ethyl ester in vivo by selective inhibition of either the L -isomer pathway with paraoxon (diethyl 4-nitrophenyl phosphate), or the D -isomer route with piperonyl butoxide. The relationship of these findings to the superior herbicidal performance of the L -isomers of these esters, relative to their racemates, is discussed.  相似文献   

8.
设计合成了一系列结构新颖的嘧啶联吡唑甲酰胺类化合物5a~5o,其结构均经过1H NM R和MS分析确证。初步生物活性测试结果表明:在有效成分150 g/hm2剂量下苗后茎叶喷雾处理时,化合物(R)-N-[1-(4-氯苯基)乙基]-3-二氟甲基-1-(4,6-二甲氧基嘧啶-2-基)-1H-吡唑-4-甲酰胺(5c)、N-[1-(4-氯苯基)乙基]-1-(4,6-二甲氧基嘧啶-2-基)-N-甲基-3-三氟甲基-1H-吡唑-4-甲酰胺(5i)和N-[1-(4-氯苯基)乙基]-1-(4,6-二甲氧基嘧啶-2-基)-3-三氟甲基-1H-吡唑-4-甲酰胺(5k)对繁缕Stellaria media的抑制率高达90%以上;而同样剂量下苗前土壤喷雾处理时,化合物N-[1-(4-氯苯基)乙基]-3-二氟甲基-1-(4,6-二甲氧基嘧啶-2-基)-1H-吡唑-4-甲酰胺(5b)和5c对繁缕的抑制率达100%。该类结构化合物有望作为除草先导化合物进行开发。  相似文献   

9.
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   

10.
The optical isomers, (R)-1(α-methylbenzyl)-3-p-tolylurea ((R)-MBU) and (S)-1-(α-methylbenzyl)-3-p-tolylurea ((S)MBU), which are analogues of daimuron [1-(α,α-dimethylbenzyl)-3-p-tolylurea], a herbicide for Cyperaceae weeds and a safener for paddy rice, exhibited different biological responses. These two physiological properties of daimuron were observed separately in (R)-MBU and (S)-MBU. Only (R)-MBU had herbicidal activity against Cyperaceae weeds, while the (S)-isomer was a more effective safener against bensulfuron-methyl (BSM) injury of rice seedlings than was (R)-MBU. (S)-MBU promoted root growth of rice seedlings, but the (R)-enantiomer inhibited root growth. (S)-MBU was a more potent inhibitor than (R)-MBU on PS II reaction of spinach broken chloroplasts. Furthermore, (S)-MBU and (R)-MBU showed cross intergenus selective phytotoxicity among the Gramineae plants, Oryza sativa L. (rice, cv. Tsukinohikari, japonica), Triticum aestivum L. (wheat, cv. Norin No. 61) and Echinochloa crusgalli var. frumentacea Wight, on root growth inhibition in the dark.  相似文献   

11.
以4,6-二氯-5-硝基嘧啶为起始原料,经过还原胺化、取代、醚化等一系列反应,得到11个未见文献报道的嘌呤氧基苯氧丙酸酯类化合物1a~1k,其结构经1H NM R和M S确认。初步生物活性测定表明:在200 mg/L下,所有目标化合物均表现出一定的除草活性,其中化合物1f((R)-2-(4-((9-(4-氯苯)-8-(三氟甲基-9H-嘌呤-6-基)氧)苯氧)丙酸丁酯)和1h((R)-2-(4-((9-(4-氯苯)-8-(三氟甲基-9H-嘌呤-6-基)氧)苯氧)丙酸乙酯)对靶标的抑制率几乎都达到100%。  相似文献   

12.
Although structure modifications of natural pyrethrin constituents have disclosed a variety of potent synthetic analogues, all known examples are cyclopropanecarboxylate esters, a grouping that appeared to be essential for insecticidal activity. Some new substituted 2-phenylalkanoates, whose biological activities are of a similar nature and potency to those of conventional pyrethroids, are now reported. 5-Benzyl-3-furylmethyl and 3-phenoxybenzyl 3-methyl-2-phenylbutyrates and their analogues are potent insecticides. Activity is increased on the introduction of appropriate groups into the 3 and/or 4-positions of the aryl ring and the (S)-2-phenylalkanoates are far more active than their (R)-enantiomorphs. Structure/activity relationships are compared with those for conventional pyrethroids. Some of the new series compare favourably with typical insecticides in tests against Musca domestica, Spodoptera litura and Plutella xylostella.  相似文献   

13.
Various isomeric mixtures of pyrethroids were examined in topical application tests against houseflies, Musca domestica. On the basis of the activities of the separate isomers of 5-benzyl-3-furylmethyl (±)-cis,trans-chrysanthemate, it was shown that when combined in pairs to give the (±)-trans or (±)-cis or (+)-cis,trans mixtures the observed mortalities did not differ from those expected by simple additive action calculated by the harmonic mean. In contrast the (±)-cis,trans mixture showed considerable antagonism with a mortality only 60% of that expected. Similar evaluations using the separate and combined isomers of bioallethrin [(R,S)-3-allyl-2-methyl-4-oxocyclopent-2-enyl (allethronyl) ( + )-trans-[(1R,3R)-chrysanthemate] and the corresponding (+)-cis-(1R,3S)-chrysanthemate indicate antagonism calculated to be correlated with the content of the (R)-isomer of the alcoholic moiety. Hence the activity of the most active isomer of the “allethrin” series, (S)-3-allyl-2-methyl-4-oxocyclopent-2-enyl ( + )-trans-(1R,3R)-chrysanthemate, (S)-bioallethrin, is not fully realised unless it is present in pure form and a substantial part of the value of bioresmethrin (5-benzyl-3-furylmethyl ( + )-trans-chrysanthemate] as a killing agent is lost when the racemic form is used. In racemic mixtures there is mutual antagonism between pairs of isomers so that considerable masking of activity occurs.  相似文献   

14.
Metalaxyl [methyl-N-(2′-methoxyacetyl)-N-(2,6-dimethylphenyl)-d,l- alaninate] is a potent phenylamide fungicide. The (−)-(R)-isomer accounts for most of the fungicidal activity. A possible stereo and/or enantioselective kinetics of metalaxyl in rabbits was investigated by intravenous injection. The concentrations of (−)-(R)- and (+)-(S)-metalaxyl in plasma, liver, and kidney tissue were determined by HPLC with a cellulose-Tris-(3,5-dimethylphenylcarbamate)-based chiral stationary phase and gas chromatography-mass spectroscopy. After intravenous administration of racemic metalaxyl (40 mg/kg), the (+)-(S)-enantiomer levels in plasma, liver, and kidney decreased more rapidly than the (−)-(R)-isomer. The area ratio of the (−)-(R)-/(+)-(S)-enantiomer under the concentration-time curve (AUC0 → ∞) in plasma after drug application was 1.62. The total plasma clearance value of the (+)-(S)-enantiomer was 1.53 and higher than that of the (−)-(R)-enantiomer. The [R]/[S] ratio in plasma was >1 for standard rac-metalaxyl at each time point. The other pharmacokinetic parameters of the enantiomers were also different. The results indicate substantial stereoselectivity in the degradation of metalaxyl enantiomers in rabbits.  相似文献   

15.
Close isosteres of fenvalerate [(RS)-α-cyano-3-phenoxybenzyl (RS)-2-(4-chlorophenyl)-3-methylbutyrate], in which cyclopropyl groups replace isopropyl have insecticidal activity close to or greater than the parent compounds, and diminished intravenous toxicity to rats. A direct toxicological relationship of these compounds to fenvalerate itself and to chrysanthemate esters is indicated by the consistently greater activity of esters from one of an enantiomeric pair of acids. Other esters with larger alkyl or cycloalkyl groups, or spiropentane analogues of chrysanthemates are less active insecticides. 13C-Nuclear magnetic resonance spectra suggest that in the α-cyanobenzyl esters there is an intramolecular through-space interaction in solution. The relationships between the chemical structures of the compounds synthesised and their relative activities to different insect species and toxicity to rats are discussed.  相似文献   

16.
A new class of insecticides and acaricides containing N-(α-substituted phenoxybenzyl)-4-pyrimidinamines as core structure were synthesized and their insecticidal and acaricidal potencies assessed. Among these, both the N-(3 or 4-phenoxybenzyl)-4-pyrimidinamine showed remarkable activity against diamondback moth, Plutella xylostella L., brown rice planthopper, Nilaparvata lugens (Stal) and two-spotted spider mite, Tetranychus urticae Koch. The potency of the new pyrimidinamines was particularly increased when a methyl, ethyl, iso-propyl, or cyclopropyl group was introduced at the α-position of benzyl moiety and it was evident that a single (+) optical isomer is more active than its antipode. Structure-activity relationships are discussed.  相似文献   

17.
Due to the presence of an asymmetrically substituted C atom, dimethenamid [2-chloro-N-(2,4-dimethyl-3-thienyl)-N-(2-methoxy-1-methylethyl)acetamide], a recently introduced N-thienyl chloroacetamide herbicide, exists as two stereoisomers (S and R) having differing herbicidal activities as demonstrated with a selection of weeds and Lemna minor. The activity of the two isomers was investigated in greater detail with the green alga Scenedesmus acutus and compared to that of alachlor [2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl)acetamide]. As with alachlor, the S isomer (5 μM ) strongly inhibited algal growth and fatty acid desaturation while the R isomer had no effect. In short-term experiments (up to 5·5 h), the S isomer and alachlor (100 μM ) inhibited [14C]acetate uptake and its incorporation into fatty acids in the same manner, while the R isomer did not. Incorporation of [14C]acetate into a non-lipid fraction of the algae was strongly inhibited by alachlor and the S isomer (100 μM ) and only slightly by the R isomer. A 50% inhibition of incorporation of [14C]oleic acid into the same non-lipid fraction was attained with less than 10-7 M of the S isomer while 10-5 M of the R form of dimethenamid achieved only a 40% inhibition. The same stereospecificity of the compound on growth, fatty acid desaturation, acetate uptake and oleic acid incorporation provides strong evidence that dimethenamid may act upon a primary, specific target in lipid metabolism. Furthermore, the comparable biological activities of dimethenamid and alachlor indicate that this target is common to both N-phenyl and N-thienyl chloroacetamide herbicides. © 1997 SCI.  相似文献   

18.
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   

19.
Non-cyclopropane pyrethroid esters of different substituted 2-phenoxy-3-methylbutanoic acids have been synthesised using the three alcohols—3-phenoxybenzyl alcohol, α-cyano-3-phenoxybenzyl alcohol and 3, 4-methylene-dioxybenzyl alcohol. Among the 35 esters synthesised and tested against Culex quinquefasciatus Say, the Bancroftian filariasis vector, for both larvicidal and adulticidal activities, α-cyano-3-phenoxybenzyl 2-(4-fluorophenoxy)-3-methylbu-tanoate, with an LC50 value of 2.5 × 10?3 mg litre?1 for larvicidal activity, and α-cyano-3-phenoxybenzyl-2-(4-chlorophenoxy)-3-methylbutanoate, with an LD50 value of 30 times; 10?4 ug insect?1 for adulticidal activity, were found to be as effective as fenvalerate, a well-known non-cyclopropane pyrethroid ester. Structure-activity studies showed that the insecticidal activity is dependent on the nature and position of the substituent in the phenyl ring of the acid moiety and also on the type of alcohol moiety.  相似文献   

20.
The four diastereomers of 2-cyano-N-[1-(2,4-dichlorophenyl)ethyl]-3,3-dimethyl-butyramide were prepared by a direct HPLC separation with chiral columns. The [(S)acid, (R)amine]-isomer (was the most antifungal among the diastereomers tested. Because of the lability of the clinical group in the acid moiety, the (RS)-(R)-isomer is being developed as a rice blasticide. (S-2900, proposed common name diclocymet).  相似文献   

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