- Development of pyrethroid substrates for esterases associated with pyrethroid resistance in the tobacco budworm, Heliothis virescens (F.)
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Assays to detect esterases associated with resistance to organophosphorus and pyrethroid insecticides in larvae of H. virescens were developed and evaluated. Cross-resistance to a variety of insecticides was measured in strains resulting from selection with either profenofos (OP-R) or cypermethrin (PYR-R), and resistance in both strains appeared to have a metabolic component. Esters were synthesized that coupled 3-(2,2-dichlorovinyl)-2,2- dimethylcyclopropanecarboxylate, the acid moiety of some pyrethroid insecticides, with groups (e.g., p-nitrophenyl-) that could be detected spectrophotometrically following hydrolysis of the resulting esters. Activities toward these pyrethroid esters were significantly higher in both resistant strains than those in a susceptible reference strain. In addition, all pyrethroid esters significantly increased the toxicity of cypermethrin in bioassays with larvae from both PYR-R and OP-R strains. The biological and biochemical activities of these compounds are compared with those with more conventional esterase substrates and insecticide synergists, and the utility of pyrethroid esters as components of rapid assays for detecting esterases associated with insecticide resistance is discussed.
- Huang, Huazhang,Ottea, James A.
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- A spectrophotometric assay for pyrethroid-cleaving enzymes in human serum
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A direct continuous spectrophotometric assay to measure pyrethroid-cleaving enzymes in human serum was developed using cis- and trans-α-naphthyl-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylate (cis- and trans-naphthyl-Cl2CA). These substrates show a structure very similar to the pyrethroids most often used (e.g. permethrin, cyfluthrin). The method is based on an increase in absorbance at 321 nm which occurs with the hydrolysis of the α-naphthyl esters to α-naphthol. The assay was optimised regarding type of buffer, pH and substrate concentrations, it was linear for at least 10 min at 37°C. These esterases were completely inhibited by bis-(4-nitrophenylphosphate), a specific carboxyesterase inhibitor. They displayed a great individual variability in human serum, activities were between less than 40 and 1000 U/l for cis-naphthyl-Cl2CA, between less than 40 and 2000 U/l for trans-naphthyl-Cl2CA, respectively. However, a correlation of enzyme activity to sex or age could not be observed. Furthermore, the activity of pyrethroid-cleaving esterases did not correspond to the activities of acylesterase, arylesterase, acetylcholinesterase or butyrylcholinesterase. Copyright (C) 1999 Elsevier Science Ireland Ltd.
- Butte, Werner,Kemper, Kerstin
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- Preparation method of cyanogen chrysanthemum ester insecticide
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The invention discloses a preparation method of a Clocythrin pesticide. The method comprises the following steps: a) mixing chrysanthemic acid and chrysanthemyl chloride and placing the mixture into a reaction vessel, adding triethylamine and introducing phosgene, slowly heating to 55-110 DEG C and fully reacting for 1-4 h so as to generate Chrysanthemoyl chloride; and b) dissolving sodium cyanide in an aqueous-phase Triton micellar solution, adding a catalyst and heating to 40 DEG C, slowly and dropwise adding mixed liquor of Chrysanthemoyl chloride and m-Phenoxybenzaldehyde, keeping the temperature and reacting for 1-4 h, cooling to 10 DEG C, adding a few amount of water and crystal seed, fully stirring and precipitating solids, and washing the precipitated solids with alkali, washing, filtering and drying so as to obtain a final product Clocythrin. The solvent in the invention can be recycled, use of the catalyst and water is reduced, and discharge of toxic wastewater and exhaust gas is minimized. The post-processing procedure is simple, and extraction and solvent distillation are not required. The final product can be obtained through simple centrifugation, washing and filtration. Discharge of solid wastes is decreased.
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Paragraph 0021; 0025
(2017/08/25)
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- Synthesis of new chiral and nonchiral pyrido [3,2-e],[1,3,4] oxadiazine derivatives
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A chiral series of 6,7-dichloro-3-[3-(2,2-dihalovinyl)-2,2-dimethylcyclopropyl] -1H-pyrido [3,2-e],[1,3,4] oxadiazines (a-f) and a nonchiral series of 3-substituted, 6,7-dichloro-1H-pyrido [3,2-e][1,3,4] oxadiazines (a-g) have been synthesized. The synthesized compounds were characterized by IR, 1H-NR, HPLC and mass spectral data.
- Shet,Shelar,Manvi
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p. 149 - 156
(2011/01/03)
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- Synthesis and evaluation of a new series of substituted acyl(thio)urea and thiadiazolo [2,3-a] pyrimidine derivatives as potent inhibitors of influenza virus neuraminidase
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A series of substituted acyl(thio)urea and 2H-1,2,4-thiadiazolo [2,3-a] pyrimidine derivatives were prepared and both of their cell culture and enzymatic activity toward influenza virus were tested. Their in vitro neuraminidase inhibitory activities were in good agreement with the corresponding activities in cultured cells and they were evaluated as potent neuraminidase inhibitors. Of the analogues that demonstrated IC50s 0.1 μM, 16 and 60 were further investigated as candidates with the most potential for future development. The molecular docking work of the representative compound was described to provide more insight into their mechanism of action and further rationalize the observations of this new series herein, which represents a novel class of highly potent and selective inhibitors of influenza virus.
- Sun, Chuanwen,Zhang, Xiaodong,Huang, Hai,Zhou, Pei
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p. 8574 - 8581
(2008/02/07)
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- Synthesis and biological activity of N′-(substituted pyrimidin-2-yl)-N-dichlorochrysanthemoyl thioureas and their fused heterocyclic compounds
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Five N′-(substituted pyrimidin-2-yl)-N-dichlorochrysanthemoyl thioureas (5a-5e) were synthesized from corresponding dichlorochrysanthemic acid in three steps. And two dichlorochrysanthemoylimino-2H-1,2,4-thiadiazolo[2,3-a] pyrimidines were prepared by oxidizing cyclization of 5a, 5b. The structures of these novel target compounds were confirmed by IR, 1H NMR and elemental analyses. The preliminary biological activity tests indicated that some target compounds had better insecticidal activity, fungicidal activity and so on mulriple efficacies.
- Xue, Sijia,Guo, Yanling,Li, Jingzhi,Ke, Shaoyong,Duan, Liping
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p. 262 - 264
(2007/10/03)
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- Parallel synthesis and herbicidal activity of pyrethroid library
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A pyridine-containing pyrethroid library of 255 compounds was conveniently constructed using parallel synthesis. The library was screened by high through-put screening (HTS), and further study was focused on the compounds with initial bioactivities. The results suggest that some compounds could be potential herbicides.
- Xiao, Yuansheng,Liang, Xinmiao,Wu, Fan,Wan, Boshun
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p. 251 - 253
(2007/10/03)
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- Hapten and antibody production for a sensitive immunoassay determining a human urinary metabolite of the pyrethroid insecticide permethrin
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Permethrin is the most popular synthetic pyrethroid insecticide in agriculture and public health. For the development of the enzyme-linked immunosorbent assay (ELISA) to evaluate human exposure to permethrin, the glycine conjugate (DCCA-glycine) of a major metabolite, cis/trans-3-(2,2- dichlorovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid (DCCA), of permethrin was established as the target analyte. Four different types of the cis- and trans-isomers of immunizing haptens were synthesized as follows: N-(cis/trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane-1-carbonyl)glycine (hapten 3), N-(cis/trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane-1- carbonyl)-4-amino-L-phenyl-alanine (hapten 5), N-(N-(cis/trans-3-(2,2- dichlorovinyl)-2,2-dimethylcyclopropane-1-carbonyl)glycine)-amino-6-(2, 4-dinitrophenyl)aminohexanoic acid (hapten 9), and N-(cis/trans-3-(2,2- dichlorovinyl)-2,2-dimethylcyclopropane-1-carbonyl)glycine-4-oxobutanoic acid (hapten 24). Sixteen polyclonal antibodies produced against each cis- or trans-hapten-thyroglobulin conjugate as immunogens were screened against numerous hapten-bovine serum albumin conjugates as coating antigens. Six ELISAs with both a heterologous hapten structure and a heterologous hapten configuration (cis/trans or trans/cis) between antibody and coating antigen showed a high sensitivity for the target analyte. The IC50 was 1.3, 2.1, and 2.2 μg/L for the trans-target analyte and 0.4, 2.3, and 2.8 μg/L for the cis-target analyte. The immunizing haptens, except for hapten 5, provided the target specific antibodies. Molecular modeling of the haptens supported the selection of reasonable immunizing haptens that best mimicked the target analyte. Hapten 5 was suitable as a coating antigen rather than as an immunogen since it had a different geometry. Very low cross-reactivities were measured to permethrin, its free metabolite (DCCA), PBA-glycine conjugate, and glycine. The ELISA will be optimized for the detection of total cis/trans-DCCA-glycine in human urine samples.
- Ahn, Ki Chang,Watanabe, Takaho,Gee, Shirley J.,Hammock, Bruce D.
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p. 4583 - 4594
(2007/10/03)
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- Syntheses of 4-methoxymethylbenzyl permethrinates containing fluorine and their insecticidal activity
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In order to investigate the relationship between the position of fluorine atom and insecticidal activity about 4-methoxymethylbenzyl permethrinates containing fluorine, 2 and 3-fluoro-4-methoxymethylbenzyl (±)-cis-permethrinate were synthesized. Their insecticidal activities were tested and the fluorine effect of title compounds was discussed.
- Zou, Xinzhuo,Qiu, Zongxing
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p. 173 - 179
(2007/10/03)
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- Enzyme-linked immunosorbent assay for the pyrethroid deltamethrin
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A competitive enzyme-linked immunosorbent assay (ELISA) for the detection of deltamethrin was developed. Two haptens, cyano[3-(4-aminophenoxy)phenyl]methyl 1 R-cis-3-(2,2-dibromoethenyl)-2,2-dimethylcyclopropanecarboxylate and 3-[(±)-cyano[1R-cis-3-(2,2-dibromoethenyl)-2,2-dimethylcyclopropan ecarbonyloxy]methyl] phenoxyacetic acid, were synthesized and conjugated with thyroglobulin as immunogens. Four antisera were generated and screened against six different coating antigens. The assay that was the most sensitive for deltamethrin was optimized and characterized. The /50 for deltamethrin was 17.5 ± 3.6 μg/L, and the lower detection limit was 1.1 ± 0.5 μg/L. This ELISA assay had relatively low cross-reactivities with other major pyrethroids, such as permethrin, phenothrin, bioresmethrin, cyfluthrin, and cypermethrin. Methanol was found to be the best organic cosolvent for this ELISA, with optimal sensitivity observed at a concentration of 40% (v/v). The assay parameters were unchanged at pH values between 5.0 and 8.0, whereas higher ionic strengths strongly suppressed the absorbances. To increase the sensitivity of the overall method, a C18 sorbent-based solid-phase extraction was used for river water samples. River water samples fortified with deltamethrin were analyzed according to this method. Good recoveries and correlation with spike levels were observed.
- Lee, Hu-Jang,Shan, Guomin,Watanabe, Takaho,Stoutamire, Donald W.,Gee, Shirley J.,Hammock, Bruce D.
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p. 5526 - 5532
(2007/10/03)
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- Enzyme-Linked immunosorbent assay for the pyrethroid permethrin
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Permethrin is a predominant pyrethroid widely used in agriculture and public health. A competitive enzyme-linked immunosorbent assay (ELISA) for the detection of permethrin was developed. Two haptens, the trans- and cis-isomers of 3-(4-aminophenoxy)benzyl-3-(2,2-dichloroethenyl)-2,2-dimethylcyclopropanecarb oxylate, were synthesized and conjugated with thyroglobulin as immunogens. Four antisera were generated and screened against six different coating antigens. The resulting ELISA has an I50 value of 2.50/μg/L and relatively low cross-reactivities with other major pyrethroids, such as esfenvalerate, cypermethrin, deltamethrin, and cyfluthrin. Methanol was found to be the best solvent for this ELISA, with optimal sensitivity observed at a concentration of 40% (v/v). The assay parameters are unchanged at pH values between 5.0 and 8.0, whereas higher ionic strengths (>0.2 M PBS) strongly suppress the absorbances. River water samples fortified with permethrin were analyzed according to this method and validated by GC-MS. Good recoveries and correlation with spike levels were observed, suggesting this immunoassay is valuable for environmental monitoring and toxicological studies at parts per trillion levels of permethrin.
- Shan, Guomin,Leeman, Whitney R.,Stoutamire, Donald W.,Gee, Shirley J.,Chang, Daniel P.Y.,Hammock, Bruce D.
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p. 4032 - 4040
(2007/10/03)
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- Development of Immunoassays for Type II Synthetic Pyrethroids. 1. Hapten Design and Application to Heterologous and Homologous Assays
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Immunoassays differing in selectivities for pyrethroid insecticides have been developed for the detection of type II pyrethroids, including deltamethrin, cypermethrin, and λ-cyhalothrin. Two approaches were employed in hapten synthesis to raise antibodies with different cross-reactions: (1) use of three spacer attachment points to offset different parts of molecules from the points of attachment and (2) use of linkers with and without bulky groups in the enzyme conjugate to reduce antibody affinities for the spacer arm in the immunoassay. The first approach resulted in the preparation of three series of haptens with a spacer attached (1) at the aromatic moiety of pyrethroid, (2) through the middle of the molecule, and (3) at the cyclopropane moiety. Haptens based on the derivatives of the pyrethroid metabolites were also prepared. The second approach involved the use of a linker with a bulky (cyclohexane ring) functionality for preparation of an enzyme conjugate. While most combinations of antibody and conjugate could be used in immunoassays for detection of deltamethrin in the 10-100 μg/L range, in most cases the limits of detection of the assays (for total isomers of a particular target pyrethroid) were lowered 10-50 fold by treatment of the pyrethroid standards with dilute alkali to produce a different isomer mix. Fifteen antisera prepared using 8 haptens were each screened with 14 peroxidase conjugates, and 26 antibody/conjugate combinations were selected for further study on the basis of the assay sensitivity, dynamic behavior, and specificity for deltamethrin, cypermethrin, and cyhalothrin. These immunoassays provided 50% inhibition of antibody binding (IC50) values between 1.5 and 4.2 μg/L of isomerized total deltamethrin and limits of detection of 0.2-0.7 μg/L. The most sensitive immunoassay for total deltamethrin was obtained using cypermethric acid-KLH as the immunogen and a conjugate based on a derivative of cypermethrin coupled through the middle of the molecule to peroxidase. These provided an IC50 of 2 μg/L and a limit of detection of 0.2 μg/L of isomerized total deltamethrin. However, no particular hapten design produced antisera of clearly superior sensitivity or specificity for deltamethrin. Differing cross-reactions with the closely related pyrethroids, deltamethrin, cypermethrin, and cyhalothrin, were obtained, and for several antibodies the cross-reaction as well as the limits of detection could be altered by varying the conjugate combinations. Each of the 12 antibody/enzyme conjugate combinations that sensitively detected deltamethrin were very stereospecific, detecting the αS, 1R cis, (DM1), and αR, 1R cis (DM2) isomers only; the assay sensitivity was greater for the latter isomer.
- Lee, Nanju,McAdam, David P.,Skerritt, John H.
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p. 520 - 534
(2007/10/03)
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- Synthesis and Larvicidal Properties of Some Cyclopropylcarboxamides Related to cis-Permethrin
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Twenty-seven carboxamide derivatives of (±)-cis-3-(2,2-dichloroethenyl)-2,2-dimethylcyclopropanecarboxylic acid (permethrin acid) have been synthesized and evaluated in the laboratory against mosquito larvae (Aedes aegypti). These cis-cyclopropylcarboxamides, with N-(substituted)phenyl, N-(substituted)phenylmethyl, N-(substituted)phenylethyl, N-phenylpropyl, and N-phenylbutyl groups, were synthesized from the acid chloride of permethrin acid and various arylamines in methylene chloride. The samples were characterized by 13C NMR spectroscopy and mass spectrometry. Secondary amides with electron-donating (e.g., methoxy) and electron-withdrawing (e.g., trifluoromethyl) substituants on the phenyl ring as well as nine tertiary amides were investigated. 3-(2,2-Dichloroethenyl)-2,2-dimethyl-N-(3-phenoxyphenyl) methylcyclopropanecarboxamide was the most active experimental compound and was 25 times less potent than (±)-cis-permethrin. Cyclopropylcarboxamides of the N-(substituted)phenyl, N-(substituted)phenylethyl, and N-phenylpropyl types were essentially inactive in the larvicidal tests.
- Taylor, Wesley G.,Hall, Tse Wai,Vedres, Darrell D.
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p. 1572 - 1576
(2007/10/03)
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- Biological Activity of Pyrethroid Analogs in Pyrethroid-Susceptible and -Resistant Tobacco Budworms, Heliothis virescens (F.)
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The phenoxybenzyl moiety of conventional pyrethroids is a major site of oxidative metabolism in resistant tobacco budworms, Heliothis virescens (F.). In this study, this group was replaced with known P450 monooxygenase-inhibiting or oxidatively blocked groups. A variety of isomers (1R/1S, cis/trans) of the resulting chrysanthemates were tested as insecticides or synergists against tobacco budworms that were insecticide-susceptible (LSU) or that expressed metabolic resistance to cypermethrin (Pyr-R). A number of compounds with pentafluorophenyl, methylenedioxyphenyl, and propargyloxyphenyl groups were insecticidal, and activity was dependent on both geometric and stereochemical configuration of the acid moiety. Both trans and cis isomers of 1(R)-fenfluthrin, which contains a pentafluorophenyl group, suppressed resistance to cypermethrin in Pyr-R insects, confirming that oxidative metabolism of the phenoxybenzyl moiety is a major mechanism of resistance in this strain. Of the methylenedioxyphenyl compounds, 1R, trans, and cis isomers were toxic and partially suppressed resistance in Pyr-R larvae. Similarly, both trans and cis isomers of α(S),1(R)-propargyloxyphenyl-containing compounds were insecticidal. Finally, α(R),1(R)-cis-methylenedioxyphenyl- and -propargyloxyphenyl- containing compounds were nontoxic but significantly enhanced toxicity of cypermethrin.
- Shan, Guomin,Hammer, Robert P.,Ottea, James A.
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p. 4466 - 4473
(2007/10/03)
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- New Chiral Agents for Resolution of Racemic cis-Permethric and cis-Z-cyhalothric Acids
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Resolution of racemic pyrethroid acids (cis-permethric and cis-Z-cyhalothric) using stable optically active amines derived from natural monoterpene (+)-3-carene and preparation of optically active esters of the pyrethroid acids are described.
- Popov, Sergey A.,Tkachev, Alexey V.
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p. 1013 - 1018
(2007/10/03)
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- Investigation of Readily Available Chiral Compounds for Preparative Scale Resolutions
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Diastereoisomeric esters were formed by reaction of racemic carboxylic acids with the readily available hydroxy lactone derivatives, 2,3-O-isopropylidene-D(+)-ribono-1,4-lactone, D(-)-2-hydroxy-3,3-dimethylbutyro-1,4-lactone (D(-)-pantolactone) and 1,2-O-isopropylidene-(+)-a-D-glucofuranurono-6,3-lactone.In all cases separation of the diastereoisomeric esters was achieved by crystallization and/or chromatography.Purity of the diastereoisomers could be determined by h.p.l.c. or by 1H n.m.r.Hydrolysis under mild basic conditions followed by treatment with acid gave optically pure carboxylic acids.The facile separation by crystallization and/or chromatography of diastereoisomers prepared from racemic endo-1,4,5,6,7,7-hexachlorobicyclohept-5-ene-2-carboxylic acid suggested that the resolved acid may be useful as a resolving agent.This was shown by separation of diastereoisomers formed from the resolved acid and racemic 1-(3'-phenoxyphenyl)prop-2-yn-1-ol and racemic 1-cyano-1-(3'-phenoxyphenyl)methanol respectively.Optically pure 1-(3'-phenoxyphenyl)prop-2-yn-1-ol was obtained by hydrolysis of the separated diastereoisomers.
- Duke, Colin C.,Wells, Robert J.
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p. 1641 - 1654
(2007/10/02)
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- Fluoropyridinylmethyl cyclopropanecarboxylate insecticides
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Insecticidal compounds of the formula STR1 formulations thereof, their use for control of foliar or soil-borne insects, their method of preparation and certain novel intermediates for their preparation are disclosed and exemplified.
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- Pyridinyl fungicides and herbicides
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Suitably substituted 2-aminomethyl pyridines and suitably substituted 2-pyridinylcarbinols are reacted with 3-(2,2-dichloroethenyl)-2,2-dimethylcyclopropane carboxoyl chloride in an inert solvent to form a group of biologically active organic compounds. These compounds are active as fungicides, herbicides, or both.
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- Crystalline, insecticidal pyrethroid
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A crystalline, optically inactive compound, each crystal comprising an equimolar mixture of the isomers (S)-(cyano)(3-phenoxyphenyl)methyl (1R,cis)-3-(2,2-dichloroethenyl)-2,2-dimethylcyclopropanecarboxylate and (R)-(cyano)-(3-phenoxyphenyl)methyl (1S,cis)-3-(2,2-dichloroethenyl)-2,2-dimethylcyclopropanecarboxylate, its preparation by a cyclic crystallization/equilibration process, and its utility as an insecticide are described and exemplified.
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- Process for preparation of substituted cyclopropane carboxylic acids and esters thereof and intermediates of said acids and esters
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When 1-halogeno-3-alkene-2-ol is reacted with an ortho-carboxylic ester and/or a ketene acetal, a γ-halogeno-δ-unsaturated-carboxylic ester is obtained as a main reaction product. When this intermediate is treated with a basic substance, a substituted cyclopropane-carboxylic ester is formed. This ester can be used as an insecticide or an agricultural chemical as it is or after the alcohol residue of the ester has been converted to other alcohol residue.
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