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1.
Terry R. Roberts 《Pest management science》1977,8(5):463-472
The metabolism of the wild oat herbicide flamprop-methyl, methyl (±)-2-[N-(3-chloro-4-fluorophenyl)benzamido]propionate, in spring wheat grown to maturity has been studied under glasshouse and outdoor conditions. [14C]-Flamprop-methyl labelled separately in the halophenyl ring and the carbonyl of the benzoyl group was used. The major metabolite formed in plants was the corresponding carboxylic acid, II, which also occurred as conjugates. Other minor metabolites detected under glasshouse conditions only were the 3- and 4-hydroxybenzoyl analogues of flamprop-methyl and 3′-chloro-4′-fluorobenzanilide. The soil in which the plants were grown contained residues comprising mainly flamprop-methyl and II together with smaller amounts of unidentified polar material. 相似文献
2.
Flamprop-isopropyl, isopropyl (±)-2-[N-(3-chloro-4-fluorophenyl)benzamido]-propionate, has been shown to give good control of Avena spp. in barley. Results from glasshouse tests have been confirmed in field trials over two seasons, in 8 European countries, using a 200 g/litre formulation of the herbicide. In Spring barley the crop stage during which application should be made for optimum weed control and crop benefit lies between late tillering and the formation of the second node. 相似文献
3.
The degradation of the wild oat herbicide flamprop-methyl [MATAVEN, methyl (±)-N-benzoyl-N-(3-chloro-4-fluorophenyl)-2-aminopropionate] was studied in soils stored under anaerobic conditions. Comparative experiments were carried out in which soil was either covered with water or stored in an atmosphere of nitrogen. Under these anaerobic conditions, the major product was the carboxylic acid analogue (II) of flamprop-methyl, which was also a major degradation product formed in soil stored under aerobic conditions. However, the 2-, 3-, and 4-hydroxy-benzoyl analogues of II were also detected in soils stored under nitrogen or water and they were present in highest concentrations in the waterlogged soil. A further new product was also detected in waterlogged soil and it was shown to be N-benzoyl-N-(3-chloro-4-hydroxyphenyl)-2-aminopropionic acid. Although no hydroxylated derivatives of flamprop-methyl were detected in soils stored under aerobic conditions, it is possible that they were formed but underwent further degradation. 相似文献
4.
The degradation of the wild-oat herbicide flamprop-isopropyl, [isopropyl (±)-N-benzoyl-N-(3-chloro-4-fluorophenyl)alaninate], in four soils has been examined under laboratory conditions with sampling times of up to 45 weeks after treatment. The major degradation product of [14C]flamprop-isopropyl in all soils at up to 10 weeks after treatment was the carboxylic acid (±)-N-benzoyl-N-(3-chloro-4-fluorophenyl)alanine. This compound in turn underwent degradation by loss of the benzoyl group and the propionic acid moiety, with evolution of [14C]carbon dioxide to form 3-chloro-4-fluoroaniline (CFA). The CFA was formed slowly in soil and occurred mainly as a bound form. There was evidence to show that the CFA was subsequently converted into other polar products. The time for depletion of 50% of the applied herbicide was approximately 10 weeks in sandy loam and medium loam soils, 11 weeks in a clay loam soil and 23 weeks in a peat soil. 相似文献
5.
The degradation of the wild oat herbicide flamprop-methyl [methyl DL -N-benzoyl-N-(3-chloro-4-fluorophenyl)alaninate] in four soils has been studied under laboratory conditions using 14C-1abelled samples. The flamprop-methyl underwent degradation more rapidly than its analogue flamprop-isopropyl. However, similar degradation products were formed, namely the corresponding carboxylic acid and 3-chloro-4-fluoroaniline. The latter compound occurred mainly as ‘bound’ forms although evidence was obtained of limited ring-opening to give [14C]carbon dioxide. The time for depletion of 50% of the applied herbicide was approximately 1-2 weeks in sandy loam, clay and medium loam soils and 2-3 weeks in a peat soil. 相似文献
6.
The degradation of chlorotoluron, 1-(3-chloro-4-methylphenyl)-3,3-dimethylurea, was investigated in laboratory and field-grown wheat and soil. Thin-layer cochromatography and, partially, derivatization and mass spectroscopy were used to elucidate the structures of the metabolites. Wheat treated with 4-methyl[14C]-phenyl-labeled chlorotoluron rapidly metabolized the herbicide using two independent mechanisms: (I) oxidation of the 4-methylphenyl group to yield 4-hydroxy-methylphenyl and 4-carboxyphenyl derivatives; and (II) N-demethylation. Mechanism (I) clearly predominated over mechanism (II). Young wheat degraded the herbicide mainly to 4-hydroxy-methylphenyl derivatives with only a small fraction being additionally N-monodemethylated. Most of both metabolites was conjugated, most probably, with glucose. In straw and grains of mature field-grown summer wheat treated postemergence with labeled chlorotoluron at a rate corresponding to 2 kg active ingredient/hectare 2.8 ppm and 0.12 ppm radioactivity equivalent to chlorotoluron were found, respectively. About 50% of this terminal radioactivity was nonextractable by organic solvents. No chlorotoluron or its N-demethylated derivatives were present in either plant part. About 40% of the radioactivity in straw consisted of 4-carboxyphenyl derivatives half of which were N-mono- or didemethylated. The rest of the terminal radioactivity was mainly in form of the 4-hydroxymethylphenyl derivative of chlorotoluron. Less than 20% of the soluble metabolites was present as conjugates. In soil mechanism (II) exceeded mechanism (I). At harvest of the wheat the 0.4 ppm radioactivity of the 0- to 30-cm soil layer was composed of 43% chlorotoluron, 36% N-mono- and 3% N-didemethylated chlorotoluron, as well as 13% 4-carboxyphenyl derivatives partly N-demethylated. 相似文献
7.
A major factor responsible for the selectivity of chlorsulfuron [2-chloro-N-[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)aminocarbonyl]benzenesulfonamide] (formerly DPX-4189), as a postemergence herbicide for small grains is the ability of the crop plants to metabolize the herbicide. Chlorsulfuron is the active ingredient in Du Pont “Glean” weed killer. Tolerant plants such as wheat, oats, and barley rapidly metabolize chlorsulfuron to a polar, inactive product. This metabolite has been characterized as the O-glycoside of chlorsulfuron in which the phenyl ring has undergone hydroxylation followed by conjugation with a carbohydrate moiety. Sensitive broadleaf plants show little or no metabolism of chlorsulfuron. 相似文献
8.
The breakdown of the herbicide benzoylprop ethyl [SUFFIX, ethyl N-benzoyl-N-(3,4-dichlorophenyl)-2-aminopropionate] has been examined in wheat, oat, and barley seedlings after application of 14C-labeled herbicide to the foliage.Within 15 days of the application the route and rate of the breakdown were similar in the plants of all three species. Some of the herbicide was present in the plants in a complexed form which could be extracted from the plant with organic solvents and converted back into the herbicide on treatment with hot acid. Evidence was obtained for hydrolysis of the herbicide in the plant to give its des-ethyl analog which conjugated with plant sugars. There was some evidence for a small degree of degradation of benzoylprop ethyl by debenzoylation to give products which also conjugated or complexed.There was no evidence for the formation of 3,4-dichloroaniline in the plants. 相似文献
9.
Metabolism of the substituted diphenylether herbicide, acifluorfen [sodium 5-(2-chloro-4-trifluoromethylphenoxy)-2-nitrobenzoate], was studied in excised leaf tissues of soybean [Glycine max (L.) Merr. ‘Evans’]. Studies with [chlorophenyl-14C]- and [nitrophenyl-14C]acifluorfen showed that the diphenylether bond was rapidly cleaved. From 85 to 95% of the absorbed [14C]acifluorfen was metabolized in less than 24 hr. Major polar metabolites were isolated and purified by solvent partitioning, adsorption, thin layer, and high-performance liquid chromatography. The major [chlorophenyl-14C]-labeled metabolite was identified as a malonyl-β-
-glucoside (I) of 2-chloro-4-trifluoromethylphenol. Major [nitrophenyl-14C]-labeled metabolites were identified as a homoglutathione conjugate [S-(3-carboxy-4-nitrophenyl) γ-glutamyl-cysteinyl-β-alanine] (II), and a cysteine conjugate [S-(3-carboxy-4-nitrophenyl)cysteine] (III). 相似文献
10.
Pierre G. Bosio Edwin R. Cole Austin P. Woodbridge Brian L. Mathews A. Neill Wright 《Pest management science》1982,13(1):72-77
Residue data are reported for flamprop-isopropyl ( I ) in barley grain and straw samples following applications of the herbicide to crops grown in eight countries. The samples were analysed for I and its hydrolysis product N-benzoyl-N-(3-chloro-4-fluorophenyl)-DL -alanine ( II ). Following recommended applications (normally 1 kg ha?1 at Feekes scale G-I/J), residues of I and II in the grain were low (90% were <0.02 mg kg?1 for I , 86% were <0.06 mg kg?1 for II , levels which were essentially the limits of determination). Residues in straw were higher and more variable, but again 63 and 77% of samples were below 1 mg kg?1 for I and II , respectively. 相似文献
11.
W. Muecke R.E. Menzer K.O. Alt W. Richter H.O. Esser 《Pesticide biochemistry and physiology》1976,6(5):430-441
The metabolic fate of 14C-labeled chlorotoluron, i.e., 1-(3-chloro-4-methyl[4C]-phenyl)-3,3-dimethyl urea, was followed in rats. After a single oral dose the radioactivity was preferably excreted with the urine. Nine of the eleven urinary metabolites isolated, were identified by spectroscopic and derivatization techniques, whereas the structure of the remaining two metabolites was only partially elucidated. N-Demethylation and stepwise oxidation of the ring methyl group to hydroxymethyl and carboxyl derivatives were found as the major metabolic mechanisms. Both mechanisms proceeded simultaneously so that the isolated metabolites showed all combinations of N-demethylation and ring methyl group oxidation in their structures. One of these metabolites was an N-formyl derivative, being probably an intermediate product of demethylation. In the urine of rats fed doses of [14C]chlorotoluron higher than 50 mg/kg three additional metabolites with different degrees of N-dealkylation were found, the ring methyl group of which was transformed to a methylthio methyl group. The metabolites identified in the faeces were of the same type as those found in the urine. Based on the structures of the metabolites elucidated, a metabolic pathway of chlorotoluron in the rat is presented. 相似文献
12.
Treatment of germinating sorghum [Sorghum bicolor (L.) Moench] seeds with the grass herbicide, metolachlor (2-chloro-N-[2-ethyl-6-methylphenyl]-N-[2-methoxy-1-methylethyl] acetamide), causes growth retardation, promoted by thickening of the first leaf and thus inhibition of unfolding of secondary leaves, and increased ethylene production. Sorghum seeds pretreated with the safener CGA 43089 [α-(cyanomethoximino)-benzacetonitrile] exhibit neither morphological deformations nor ethylene production upon metolachlor treatment. Aminoethoxyvinylglycine [l-2-amino-4-(2-aminoethoxy)-trans-3-butenoic acid], a specific inhibitor of ethylene formation in higher plants, decreases ethylene formation by metolachlor-treated sorghum seedlings; the observed deformations, however, remain unchanged. Sorghum control seedlings which grow against a covering plate build up ethylene concentrations as after herbicide treatment, but without induction of the morphological symptoms. These observations suggest that the plant hormone ethylene is a symptom and not the inducer of the morphological effects visible after metolachlor treatment of sorghum seedlings. 相似文献
13.
《Pesticide biochemistry and physiology》1987,29(2):112-120
Chlorimuron ethyl (2-([(4-chloro-6-methoxypyrimidine-2-yl)amino carbonyl]amino sulfonyl)benzoic acid, ethyl ester) is a highly active sulfonylurea herbicide for preemergence and postemergence use in soybeans. Excised soybean (Glycine max. cv. ‘Williams’) seedlings rapidly metabolized [14C]chlorimuron ethyl with a half-life of 1–3 hr. Common cocklebur (Xanthium pensylvancium Wallr.) and redroot pigweed (Amaranthus retroflexus L.), which are sensitive to chlorimuron ethyl, metabolized this herbicide much more slowly (half-life >30 hr). The major metabolite of chlorimuron ethyl in soybean seedlings is its homoglutathione conjugate, formed by displacement of the pyrimidinyl chlorine with the cysteine sulfhydryl group of homoglutathione. A minor metabolite is chlorimuron, the deesterified derivative of chlorimuron ethyl. Each of these metabolites is inactive against plant acetolactate synthase, the herbicidal target site of chlorimuron ethyl. Thus, soybean tolerance to chlorimuron ethyl results from its rapid metabolism in soybean seedlings to herbicidally inactive products. 相似文献
14.
The post-emergence herbicide isopropyl (±)-2-[N-(3-chloro-4-fluorophenyl)benzamido]propionate (flamprop-isopropyl) showed good activity against wild oat with selectivity in barley. The basis for activity and selectivity was similar to that previously established for benzoylprop-ethyl, and found to be dependent on its rate of degradation to the biologically active acid flamprop. Flamprop stunted the growth of the oat by inhibiting cell elongation and showed a relatively high rate of movement in the phloem, approximately five times that of benzoylprop. Selectivity of flamprop-isopropyl was dependent on its relative rate of hydrolysis and the subsequent detoxication of the acid to inactive conjugates. However, although the relative rate of de-esterification of flamprop-isopropyl was lower than that of benzoylprop-ethyl similar quantities of the parent ester gave comparable effects on oat. The inherent activity of flamprop is approximately twice that of benzoylprop. The effect of flamprop-isopropyl was best seen when the compound was applied during growth stages when the crop could offer the most effective competition to the wild oat. Throughout a range of growth stages the rate of hydrolysis of flamprop-isopropyl was higher in oat than in barley. The metabolism of the compound was not markedly affected when the plants were under stress. 相似文献
15.
The route and rate of degradation of florasulam, a low‐rate triazolopyrimidine sulfonanilide herbicide, was investigated in six soil types under aerobic conditions at 20 or 25 °C. Degradation products were isolated and identified by mass spectroscopy. Florasulam was rapidly degraded by microbial action with an average half‐life of 2.4 days (range 0.7 to 4.5 days). The first step in the degradation pathway involved conversion of the methoxy group on the triazolopyrimidine ring to a hydroxy group to form N‐(2,6‐difluorophenyl)‐8‐fluoro‐5‐hydroxy[1,2,4]triazolo[1,5‐c]pyrimidine‐2‐sulfonamide. This metabolite degraded, with a half‐life of 10 to 61 days, via partial breakdown of the triazolopyrimidine ring to form N‐(2,6‐difluorophenyl)‐5‐aminosulfonyl‐1H‐1,2,4‐triazole‐3‐carboxylic acid. This was followed by cleavage of the sulfonamide bridge to form 5‐(aminosulfonyl)‐1H‐1,2,4‐triazole‐3‐carboxylic acid. Other degradation processes involved decarboxylation of the carboxylic acid metabolites and mineralisation to form carbon dioxide and non‐extractable residues. © 2000 Society of Chemical Industry 相似文献
16.
The inhibition site of the phenylpyridazinone herbicide, norflurazon [SAN 9789, 4-chloro-5-(methylamino)-2-(3-trifluoromethylphenyl)-pyridazin-3(2H)one] was determined in a cell-free carotenogenic enzyme system from a mutant strain of Phycomyces blakesleeanus (Mucoraceae). The presence of norflurazon resulted in a reduced flow of radioactivity from [2-14C]mevalonic acid to phytoene (7,8,11,12,7′,8′,11′,12′-octahydro-ψ,ψ-carotene) and β-carotene (β,β-carotene), whereas an increased incorporation occurred in the C30 terpenoids, squalene, and ergosterol. Furthermore, radioactivity accumulated in geranylgeranyl pyrophosphate. Since no radioactivity was found in prephytoene pyrophosphate and the radioactivity in phytoene decreased upon addition of norflurazon, this herbicide exerts its primary inhibitory action on the reaction catalyzed by phytoene synthetase. The nonbleaching phenylpyridazinone BAS 13761 [4-chloro-5-methoxy-2-phenyl-pyridazin-3(2H)-one] did not show this effect. Other inhibitory sites of norflurazon, either on prenyl pyrophosphate synthetase or on the desaturation of phytoene, were excluded. 相似文献
17.
K. I. Beynon 《Pest management science》1972,3(4):389-400
Radiochemical techniques have been used to develop efficient procedures for the extraction of residues of cyanazine herbicide [‘BLADEX’, 1 BLADEX and FORTROL are Shell registered Trade Marks. a ‘FORTROL’,a 2-chloro-4-(1-cyano-1-methylethylamino)-6-ethylamino-1,3,5-triazine] and its metabolites 2-chloro-4-(1-carbamoyl-1-methylethylamino)-6-ethylamino-1,3,5-triazine ( II ), 2-chloro-4-(1-cyano-1-methylethylamino)-6-amino-1,3,5-triazine ( V ) and 2-chloro-4-(1-carbamoyl-1-methylethylamino)-6-amino-1,3,5-triazine ( VI ) from crops and soils. Partition and column chromatographic techniques have been established for the purification of the extracts. The full analytical procedure is described and the final determination of all four compounds is by g.l.c. with electron capture detection with blank values for field samples generally 0.02 part/million and with good recoveries. 相似文献
18.
Radioisotope techniques have been used to study the breakdown products that are formed from the herbicide cyanazine ( BLADEX )a, 2-chloro-4-(1-cyano-1-methylethyl-amino)-6-ethylamino-1,3,5-triazine, in soils and in maize grown in the soils under indoor conditions. In soils of different types cyanazine broke down mainly by conversion of the nitrile group to amide ( II ) and then to an acid ( III ) followed by hydrolysis of the ring chlorine to hydroxyl ( IV ). Dealkylation reactions occurred to only a limited extent in soils. In maize plants grown in treated soils the hydrolysis products, the amide ( II ) and the hydroxy acid ( IV ) were detected as well as appreciable quantities of products ( VI ) and ( VIII ) formed from these by loss of the N-ethyl group. In plants the hydroxy acids ( IV ) and ( VIII ) were present in the free form and there was also evidence for conjugates which were not identified but could be converted to these hydroxy acids, ( IV ) and ( VIII ), on treatment with acids. In these indoor studies the major residues appear to be the hydroxy acid ( IV ) in soils and ( IV ) and its dealkylated analogue ( VIII ) in plants grown in treated soils. These compounds are not herbicides and are of a low order of toxicity to mammals. 相似文献
19.
Aspergillus niger converts the herbicide 3′-chloro-2-methyl-p-valerotoluidide (solan) to 3′-chloro-4′-methylacetanilide and the fungicide 2,5-dimethylfuran-3-carboxanilide to acetanilide. The metabolites were formed by hydrolysis with an aryl acylamidase, followed by subsequent acetylation resulting in the corresponding acetanilides. Their structures were elucidated by mass spectrometric analysis and confirmed by comparison with synthetic compounds. 相似文献
20.
《Pesticide biochemistry and physiology》1987,28(2):248-256
The potential involvement of hydroxyl and alkoxyl radicals in the peroxidative action of the p-nitro diphenyl ether herbicides acifluorfen (5-[2-chloro-4-(trifluoromethyl)phenoxyl]-2-nitrobenzoic acid), acifluorfen-methyl (methyl ester of acifluorfen), nitrofen [2,4-dichloro-1-(4-nitrophenoxy)benzene], nitrofluorfen [2-chloro-1-(4-nitrophenoxy)-4-(trifluoromethyl)benzene], and oxyfluorfen [2-chloro-1-(3-ethoxy-4-nitrophenoxy)-4-(trifluoromethyl)benzene] was evaluated under laboratory conditions. Methional was added to illuminated thylakoids from peas (Pisum sativum L., cv Little Marvel) and its oxidation to ethylene was used as an indicator of hydroxyl and alkoxyl radical production. Oxyfluorfen stimulated the rate of methional oxidation by 138% at 10 μM and 175% at 1 mM. This oxyfluorfen-induced stimulation of the rate of methional oxidation was dependent on light, photosynthetic electron transport, and hydrogen peroxide since it was not observed under dark conditions or in the presence of DCMU and catalase. Addition of Fe-EDTA, a catalyst of the Fenton reaction, stimulated the oxyfluorfen-induced enhancement of methional oxidation sixfold, suggesting that hydroxyl radicals are synthesized through a Fenton reaction. Acifluorfen, nitrofen, and nitrofluorfen inhibited the rate of methional oxidation whereas acifluorfen-methyl had no effect on the rate of methional oxidation, even at high concentrations (1 mM). Nitrofluorfen at 1 mM was the only p-nitro diphenyl ether herbicide tested to inhibit photosynthetic electron transport of pea thylakoids. In experiments with pea leaf disks, acifluorfen at low concentrations stimulated the rate of methional oxidation, whereas acifluorfen-methyl, nitrofen, and nitrofluorfen had no effect. These data indicate that hydroxyl and alkoxyl radicals could be involved in the mechanism of cellular damage caused by oxyfluorfen but they are not important for the activity of the diphenyl ether herbicides acifluorfen, acifluorfen-methyl, nitrofen, and nitrofluorfen. 相似文献