GABA receptor antagonists and insecticides: common structural features of 4-alkyl-1-phenylpyrazoles and 4-alkyl-1-phenyltrioxabicyclooctanes

Sammelson, Robert Erik; Caboni, Pierluigi; Durkin, Kathleen A.; Casida, John E.

doi:10.1016/j.bmc.2004.03.069

Cited by 65 publications

(26 citation statements)

References 24 publications

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“…Hence, two TSs, designated TS-C-x and TS-N-x, and the corresponding cycloadducts (CAs), CA-C-x and CA-N-x where x (x = a, b, c, d, e, f, g or h), were located and characterised. Moreover, two TSs related to [1,5]-H shifts of CAs, TSt-C-x and TSt-N-x, and the corresponding final products, P-C-x and P-N-x, were also investigated. IRC calculations were carried out for all studied reactions, and are presented only for the reaction between EDA and 2e via the C-regioisomeric pathway in Figure 1.…”

Section: Analysis Based On Energetic Aspectsmentioning

confidence: 99%

“…Beside their applications as potent pesticides [1,2] and herbicides [3], they are also widely used as anti-inflammatory [4 -8], anti-bacterial [9], anti-diabetic [10 -12] and anti-cancer [13 -17] agents. One of the most simple, yet important methods for pyrazole synthesis is the 1,3-dipolar cycloaddition (1,3-DC) between a diazo compound and an alkyne.…”

Section: Introductionmentioning

confidence: 99%

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1,3-Dipolar Cycloaddition Reactions between Ethyl Diazoacetate and Substituted Alkynes: A Density Functional Theory Study

Tajabadi

Bakavoli

Gholizadeh

et al. 2014

Progress in Reaction Kinetics and Mechanism

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A theoretical study on the reactivity and regioselectivity of 1,3-dipolar cycloaddition reactions of ethyl diazoacetate (EDA) with ethynes (CH ≡ CX, X = H, CH 3 , n-But, CF 3 , CO 2 Et, C 6 H 5 , p-CH 3 OC 6 H 4 and p-NO 2 C 6 H 4 ) has been carried out by means of several theoretical approaches, activation energies, frontier molecular orbital (FMO) theory, conceptual density functional theory reactivity indices and hard and soft acid and base theory. Potential energy surface analysis and intrinsic reaction coordinate calculations show that these cycloadditions follow an asynchronous concerted mechanism with a low or non-polar character, displaying C-regioselectivity. Moreover, the reaction of EDA with electron-deficient alkynes is faster compare to electron-rich ethynes. Reactions of EDA with electron-deficient and electron-rich alkynes are normal electron demand and inverse electron demand cycloadditions, respectively, because of moderate electrophilicity and nucleophilicity of EDA. This result is confirmed by FMO analysis and reactivity indices.Scheme 1 A schematic representation of the stationary points along the two reactive channels.

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Section: Analysis Based On Energetic Aspectsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

1,3-Dipolar Cycloaddition Reactions between Ethyl Diazoacetate and Substituted Alkynes: A Density Functional Theory Study

Tajabadi

Bakavoli

Gholizadeh

et al. 2014

Progress in Reaction Kinetics and Mechanism

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“…The resulting α,β-dicyanopropanoates are valuable intermediates for the synthesis of medicines and can be readily transformed into acids, esters, amides and amines (Rappoport, 1970). To date, many cyanating reagents have been used as additions to α,β-unsaturated esters, such as HCN (Griffiths et al, 1991), KCN (Aizencang et al, 1995;Sammelson et al, 2004), NaCN (Das et al, 2008;Rajib et al, 2012), TMSCN (Mazet & Jacobsen, 2008;Sammis et al, 2004), CNCOOEt (Wang et al, 2010) and acetone cyanohydrins (Wakita et al, 1990). However, some problems continue to be associated with the use of the existing cyanating reagents, including strong toxicity for KCN and NaCN, volatility for HCN, instability for acetone cyanohydrins, and moisture sensibility for TMSCN and CNCOOEt.…”

Section: Introductionmentioning

confidence: 99%

Eco-friendly conjugate hydrocyanation of α-cyanoacrylates using potassium hexacyanoferrate(II) as cyanating reagent

Zhang

2015

Chemical Papers

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The conjugate hydrocyanation of α-cyanoacrylates through chemoselective 1,4-addition to synthesise α,β-dicyanopropanoates by one-pot two-step procedure using potassium hexacyanoferrate(II) as an eco-friendly cyanide source, benzoyl chloride as a promoter and potassium carbonate as a catalyst is described. The advantages of this protocol are use of a non-toxic, non-volatile and inexpensive cyanating reagent, high product yields and simple working procedure.

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“…Fipronil, a member of the phenyl pyrazole class of pesticides, [(±)-5-amino-1-(2,6-dichloro-a,a,a-trifluoro-p-tolyl)-4-trifluoromethylsulfinylpyrazole-3-carbonitrile], is a GABA-gated chloride channel antagonist. Fipronil binds to some sites on γ-aminobutyric acid (GABA), blocking the passage of chloride ions, resulting in excessive release of neuronal stimulation and death of the target insect [2]. Fipronil has been effectively delivered to target pests via soil, foliar, bait or seed treatment and has been found to be effective against many species of soil insects [3].…”

Section: Introductionmentioning

confidence: 99%

Residue analysis and persistence evaluation of fipronil and its metabolites in cotton using high-performance liquid chromatography-tandem mass spectrometry

et al. 2017

PLoS ONE

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A simple residue analytical method based on the QuEChERS approach and high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) detection was developed for the analysis of fipronil and its three metabolites in cottonseed, cotton plant and soil. The average recoveries of four test compounds from all three matrices were 78.6–108.9% at the level of 0.005 to 0.5 mg/kg, with an RSD in the range of 0.6 to 13.7%. The limit of quantification (LOQ) of the four test compounds ranged from 0.005 to 0.01 mg/kg. The results of the residual dynamics experiments showed that fipronil dissipated rapidly in cotton plants and soil and that oxidation and photolysis were the main degradation pathways. Moreover, the bi-exponential models demonstrated a good fit of the measured data for fipronil in cotton plants and soil, with R2 in the range of 0.8989 to 0.9989. Furthermore, a total of 40 samples of cottonseed from Shandong Province were analyzed, and all of the samples were free from the four test compound residues.

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GABA receptor antagonists and insecticides: common structural features of 4-alkyl-1-phenylpyrazoles and 4-alkyl-1-phenyltrioxabicyclooctanes

Cited by 65 publications

References 24 publications

1,3-Dipolar Cycloaddition Reactions between Ethyl Diazoacetate and Substituted Alkynes: A Density Functional Theory Study

1,3-Dipolar Cycloaddition Reactions between Ethyl Diazoacetate and Substituted Alkynes: A Density Functional Theory Study

Eco-friendly conjugate hydrocyanation of α-cyanoacrylates using potassium hexacyanoferrate(II) as cyanating reagent

Residue analysis and persistence evaluation of fipronil and its metabolites in cotton using high-performance liquid chromatography-tandem mass spectrometry

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