New potent diphenyl ether herbicides

Yih, Roy Y.; Swithenbank, Colin

doi:10.1021/jf60199a062

Cited by 41 publications

(21 citation statements)

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“…[1] It is well-documented that nitrodiphenyl ether herbicides requires light to disrupt the membrane permeability, elicit biochemical changes and kill plant cells, [2,3] possibly involving light-induced reduction for herbicidal activity. [4] The photochemical fate of substituted nitrodiphenyl ethers has received some attention in the past [5][6][7][8][9][10][11][12] due to increased interest in the environmental chemistry of such compounds.…”

Section: Oxyfluorfenmentioning

confidence: 99%

Photolysis of oxyfluorfen in aqueous methanol

Chakraborty

Bhattacharyya

et al. 2013

Journal of Environmental Science and Health, Part B

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Photolysis of oxyfluorfen, an herbicide of the nitrodiphenyl ether class, was studied in aqueous methanol under UV and sunlight. UV irradiation was carried out in a borosilicate glass photoreactor (containing 250 ppm oxyfluorfen in 50% aqueous methanol) equipped with a quartz filter and 125 watt mercury lamp (maximum output 254 nm) at 25 ± 1°C. Sunlight irradiation was conducted at 28 ± 1°C in borosilicate Erlenmeyer flasks containing 250 ppm oxyfluorfen in 50% aqueous methanol. The samples from both the irradiated conditions were withdrawn at a definite time interval and extracted to measure oxyfluorfen content by gas chromatography-flame ionization detector for rate study. The half-life values were 20 hours and 2.7 days under UV and sunlight exposure, respectively. Photolysis of oxyfluorfen yielded 13 photoproducts of which three were characterized by infrared spectrophotometer and (1)H NMR and (13)C NMR spectroscopy. The rest of the photoproducts were identified by gas chromatography-mass spectrometry (GC-MS) and thin layer chromatography (TLC). An ionization potential 70 eV was used for electron impact-mass spectrometry (EI-MS) and methane was used as reagent gas for chemical ionization-mass spectrometry (CI-MS). Two of the photoproducts were also synthesized for comparison. The main phototransformation pathways of oxyfluorfen involved nitro reduction, dechlorination, and hydrolysis as well as nucleophiles displacement reaction.

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Section: Oxyfluorfenmentioning

confidence: 99%

Photolysis of oxyfluorfen in aqueous methanol

Chakraborty

Bhattacharyya

et al. 2013

Journal of Environmental Science and Health, Part B

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“…1-Aryl-3, 5-dialkyl-4-(un)substituted pyrazoles (1)(2)(3)(4)(5)(6)(7)(8)(9)(10) were prepared by the condensation reaction of corresponding hydrazines with 3-(un)substituted 2, 4-pentanediones or their homologues. " 5-Amino-4-cyano-l -(2, 6-dichloro-4-trifluoromethylphenyl)pyrazole (11; M & B 39279) was synthesized from ethoxymethylenemalononitrile and 2, 6-dichloro-4-(trifluoromethyl) phenylhydrazine in refluxing acetic acid, according to Hatton et al 8) 5-Chloro-l-(4-chloro-5-difluoromethoxy-2-fluorophenyl)-3, 4-tetramethylenepyrazole (12) was synthesized by the reaction of 2-(4-chloro-5difluoromethoxy-2-fluorophenyl)-1, 2, 4, 5, 6, 7hexahydro-3H-indazol-3-one, prepared from 2ethoxycarbonylcyclohexanone and the corresponding hydrazine, with phosphorus oxychloride.…”

Section: Chemicalsmentioning

confidence: 99%

Peroxidizing Phytotoxic Activity of Pyrazoles

et al. 1995

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Using autotrophic Scenedesmus cells and maize protoporphyrinogen-IX oxidase, twelve pyrazole compounds recently synthesized were assayed with respect to peroxidizing phytotoxic activity. Three pyrazoles, namely 1-(4-chloro-2-fluoro-5-propargyloxyphenyl)-3, 5-dimethyl-4-nitropyrazole, 5-amino-4-cyano-l-(2, 6-dichloro-4-trifluoromethylphenyl)pyrazole and 5chloro-l-(4-chloro-5-difluoromethoxy-2-fluorophenyl)-3, 4-tetramethylenepyrazole, strongly inhibited growth of the Scenedesmus cells and caused severe chlorophyll deficiency (bleaching activity) at a 10-6 M concentration. The three pyrazoles mentioned were selected for a further quantitative study to determine whether the chlorophyll decrease observed was due to inhibition of pigment biosynthesis or to peroxidative destruction of existing chlorophyll. The pyrazoles inhibited protoporphyrinogen-IX oxidase, caused not only accumulation of protoporphyrin-IX but also light-induced ethane formation. Thus, the three pyrazoles (1, 11 and 12) were identified as peroxidizing herbicides. A 1-(4-chloro-2-fluoro-5-substituted)phenyl moiety at the pyrazole ring appears to be essential for producing active peroxidizing compounds.

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“…is excreted unmetabolized in the urine, but the majority of the urinary metabolites are, like pronamide, amides that yield 3,5-dichlorobenzoic acid upon hydrolysis (Yih and Swithenbank, 1971). The hydrolysis of pronamide and ita metabolites to the common product has been applied previously for analytical purposes (Adler et al, 1972).…”

Section: Analysis Of Urine Only a Small Fraction Of Pronamidementioning

confidence: 99%

A multiresidue procedure for the determination and confirmation of acidic herbicide residues in human urine

Draper¹

1982

J. Agric. Food Chem.

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New potent diphenyl ether herbicides

Cited by 41 publications

References 0 publications

Photolysis of oxyfluorfen in aqueous methanol

Photolysis of oxyfluorfen in aqueous methanol

Peroxidizing Phytotoxic Activity of Pyrazoles

A multiresidue procedure for the determination and confirmation of acidic herbicide residues in human urine

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