Synthesis of a chlorothalonil peptide conjugate mimicking protein-bound pesticide residues

Hrenn, Holger; Schwack, Wolfgang; Seilmeier, Werner; Wieser, Herbert

doi:10.1016/s0040-4039(03)00121-7

Cited by 4 publications

(2 citation statements)

References 7 publications

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“…In addition, the cutin component of leaf surfaces has been shown to act as a covalent binding partner,27 with photochemistry being involved in the cases of chlorothalonil22, 23 and parathion 25. Defined adducts have been chemically or enzymatically prepared in the case of xenobiotic lignin28, 29 and protein30, 31 conjugates. Plants are also known to be capable of mutagenic activation, so that binding of xenobiotics to DNA and soluble proteins appears possible 32, 33.…”

Section: Plant Matrix Macromolecules Involvedmentioning

confidence: 99%

Bound and unextractable pesticidal plant residues: chemical characterization and consumer exposure

Sandermann

2004

Pest Management Science

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Plants are well known to incorporate pesticides into bound and unextractable residues that resist solubilization in common laboratory solvents and are therefore not accessible to standard residue analysis. A characterization of such residues has been proposed for incorporation rates above trigger values of 0.05 mg kg(-1) parent pesticide equivalents, or percentage values of 10% (United States Environmental Protection Agency, 1995) or 25% (Commission of the European Communities, 1997) of the total radioactive residue. These trigger values are often exceeded. The present review describes the current status of the chemical characterization and animal bioavailability of bound and unextractable residues that may be xenobiotic in nature or result from natural recycling of simple degradation products. The latter case represents a mechanism of detoxification. Bound residues have been shown to be covalent or non-covalent in nature. With regard to the plant matrix molecules involved, incorporation into proteins, lignins, pectins, hemicelluloses and cutins has been demonstrated, and four covalent linkage types are known. Animal feeding experiments have revealed cases of low as well as high bioavailability. Many of the studies are limited by experimental uncertainties and by results only being reported as relative percentage values rather than absolute exposure. A preliminary value of absolute exposure from bound and unextractable residues is derived here for the first time from eight case studies. The mean exposure (ca 1.5 mg kg(-1) pesticidal equivalents) exceeds some of the existing maximum residue levels (MRLs) of residual free pesticides that are typically in the range of 0.05-1 mg kg(-1). A mathematical framework for the correction of current maximum residue levels is presented for cases of highly bioavailable bound residues. As bound pesticidal residues in food plants could represent a source of significant consumer exposure, an experimental test scheme is proposed here. It consists of basic chemical characterization, model digestibility tests and, in exceptional cases, animal bioavailability and additional toxicological studies.

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Section: Plant Matrix Macromolecules Involvedmentioning

confidence: 99%

Bound and unextractable pesticidal plant residues: chemical characterization and consumer exposure

Sandermann

2004

Pest Management Science

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“…It is effective against fungal diseases, such as gray mold, early and late blights, leaf spots, anthracnose, fruit rots, rusts, and downy mildews, that threaten numerous vegetable, small fruit, stone fruit, ornamental, turf, and other agricultural crops with both lower manufacturing cost and relatively low toxicity of LD 50 > 10 000 mg/kg orally of rats . Because of its success in crop protection, a great deal of synthetic work has been performed, aimed at creating various analogues of chlorothalonil. − Our interest in chlorothalonil analogues was to apply our new agrochemical discovery approach, which we call intermediate derivatization methods, to try to obtain novel fungicidally active compounds.…”

Section: Introductionmentioning

confidence: 99%

Design, Synthesis, and Structure–Activity Relationship of Novel Aniline Derivatives of Chlorothalonil

Guan¹,

Liu²,

Huang³

et al. 2013

J. Agric. Food Chem.

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Chlorothalonil with both low cost and low toxicity is a popularly used fungicide in the agrochemical field. The presence of nucleophilic groups on this compound allows further chemical modifications to obtain novel chlorothalonil derivatives. Fluazinam, another commercially available agent with a broad fungicidal spectrum, has a scaffold of diaryl amine structure. To mimic this backbone structure, a variety of (un)substituted phenyl amines was used as nucleophilic agents to react with chlorothalonil to obtain compounds with a diphenyl amine structure. Via an elegant design, two leads, 2,4,5-trichloro-6-(2,4-dichlorophenylamino)isophthalonitrile (7) and 2,4,5-trichloro-6-(2,4,6-trichlorophenylamino)isophthalonitrile (11), with potential fungicidal activity were discovered after a preliminary bioassay screen. These two leads were further modified to obtain final products by replacing the chlorine groups in the phenyl ring in phenyl amine with other functional groups. These functional groups with various electronic properties and spatial characteristics were considered to explore the relationship between structure and fungicidal activity. The results indicate that the electron-withdrawing group NO2 on the 4 position on the right phenyl ring plays a unique role on enhancing the fungicidal activity. The compounds were identified by proton nuclear magnetic resonance and elemental analysis. Bioassays demonstrated that some of the title compounds exhibited excellent fungicidal activities against cucumber downy mildew at 25 mg/L. Compound 20 has been shown as the optimal structure with 85% control against cucumber downy mildew at 6.25 mg/L concentration. The relationship between structure and fungicidal activity is reported. The present work demonstrates that chlorothalonil derivatives can be used as possible lead compounds for developing novel fungicides.

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Evaluation of some parameters affecting troublesome pesticide analysis in gas chromatography–ion-trap mass spectrometry

Przybylski

Hommet

2008

Journal of Chromatography A

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Synthesis of a chlorothalonil peptide conjugate mimicking protein-bound pesticide residues

Cited by 4 publications

References 7 publications

Bound and unextractable pesticidal plant residues: chemical characterization and consumer exposure

Bound and unextractable pesticidal plant residues: chemical characterization and consumer exposure

Design, Synthesis, and Structure–Activity Relationship of Novel Aniline Derivatives of Chlorothalonil

Evaluation of some parameters affecting troublesome pesticide analysis in gas chromatography–ion-trap mass spectrometry

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