4-Chloro-2-methyl-phenoxy-acetic acid

Chau and Terry [146] reported the formation of penta-fluorobenzyl derivatives of ten herbicidal acids including 4-chloro-2-methyl-phenoxy acetic acid [145]. They found that 5h was an optimum reaction time at room temperature with pentafluorobenzyl bromide in the presence of potassium carbonate solution. Agemian and Chau [147] studied the residue analysis of 4-chloro-2-methyl phenoxy acetic acid and 4-chloro-2-methyl phenoxy butyric acid from water samples by making the pentafluorobenzyl derivatives. Bromination [148], nitrification [149] and esterification with halogenated alcohol [145] have also been used to study the residue analysis of 4-chloro-2-methyl phenoxy acetic acid and 4-chloro-2-methyl phenoxybutyric acid. Recently pentafluorobenzyl derivatives of phenols and carboxylic acids were prepared for detection by electron capture at very low levels [150, 151]. Pentafluorobenzyl bromide has also been used for the analytical determination of organophosphorus pesticides [152],... 

Saltar and Paasivirta [155] have described a method for the analysis in soils of MCPA (4-chloro-2-methyl phenoxy acetic acid) and two of its main metabolites, 4-chloro-o-cresol and 6-chloromethyl catechol by gas chromatography of their pentafluorobenzyl derivatives (Fig. 9.12). After derivitization of the residue extract, a clean-up procedure was applied. The best recoveries of compounds from soil were obtained when the extraction was performed by shaking with ether-acetone-heptane-hexane (2 1 1 1) from acidified soil and when the clean-up was done by thin layer chromatography (Table 9.17). Detection limits were in the range 20-25ng absolute. 

Waliszewski and Szynczynski [158] have described a gas chromatographic method for the determination of 4-chloro-2-methyl phenoxy acetic acid (MCPA) and 2.4 chloro phenoxy acetic acid (2.4D) herbicides in soils. The chlorophenoxy acetic acid herbicides were extracted from soil... 

Dichlorophenoxy)propionic acid) 2,4,5-T (2,4,5-Trichlorophenoxy acetic acid) Dicamba (3,6-Dichloro-o-anisic acid) MCPA (4-Chloro-2-methyl-phenoxy acetic acid) MCPP (2-(4-Chloro-2-methylphenoxy)propionic acid) Silvex (2-(2,4,... 

METAXONE METHOXONE (2-METEm 4-CHLOROPHENOXY)ACETIC ACID, SODIUM SALT 2M-4KH SODIUM SALT 2M-4X Na MCPA PHENOXYLENE SODIUM (4-CHLORO-2-METHYL-PHENOXY)ACETATE SODIUM MCPA SYS 67ME... 

Of the alkanoic acids with a phenoxy group in the 2 position, D-enan-tiomers of propanoic and butanoic acid have higher activities than phenoxy acetic acids. If the phenoxy group is further away, there must be a metabolic activation, as shown for 4-(4-chloro-2-methyl-phenoxybutanoic acid (MCPB). 

Figure 22 GC chromatogram of TMAH intrainjector derivatized phenoxy acids. Peaks 1 =2-phenoxypropionic acid 2=p-fluor-ophenoxyacetic acid 3=2-methylphenoxyacelic acid 4=3-me-thylphenoxyacetic acid 5=4-melhylphenoxyacetic acid 6= 2-formylphenoxyacetic acid 7=2,5-dimethylphenoxyacetic acid 8=2-(4-chlorophenoxy)propionic acid 9=2,4-dimethylphenoxy-acetic acid 10=2-methoxyphenoxyace1ic acid 11=4-phenox-ybutyric acid 12=3-melhoxyphenoxyacetic acid 13= 4-methoxyphenoxyacetic acid 14=2-(4-chloro-2-methyl-phenoxy)propionic acid 15 = 4-chloro-2-methylphenoxyacetic acid 16 = 2,4-dichlorophenoxypropionic acid 17 = iodophenoxy-xyacetic acid 18 = a-(2,4,5-trichlorophenoxy)propionic acid 19 = 2,4,5- trichlorophenoxyacetic acid. (Reproduced with permission from Brondz I and Olsen I (1992) Intra-injector formation of methyl esters from phenoxy acid pesticides. Journal of Chro-matogreiphy 598 309-312.)...

Experiments were conducted to determine how quickly a low concentration (1.4 /zM) of an aryloxyphenoxypropanoate, haloxyfop (2-[4-[[3-chloro-5-(trifluoromethyl)-2-pyridinyl]oxy]phenoxy]-propanoic acid) (Fig.l) could affect lipid metabolism. We used leaf discs as experimental material because it would mitigate effects of herbicide uptake and translocation. Maize (Zea mays) leaf discs were prepared as previously described (15) and incubated in C-acetate. At various times, discs were removed and cell constituents were separated into organic and aqueous soluble fractions (16). Within 30 min of application, 1.4 /zM of either the free acid or the methyl ester of haloxyfop inhibited lipid... 

The effect of the degree d xrlarization of the ester linkages in low-motecular-weight esters on their reactivity has been examined by studying the reaction of alcoholysis, with ceUulose, of methyl esters of benzoic, p-chloro-, p-hydroxy, p-hydroxy-, p- and o-nitrobenzoic acids, and those of phenyl-, phenoxy-, 2,4-dichlorophenoxy- and monodiloro-acetic adds. The trans-esterification reaction was carried out in non-aqueous dinrethylformamide in the presence of catalysts (sodium methylate, cadmium acetate, p-toluenesulphonic add) at 110-140° C. 

Phenoxy acids (2,4-dichlorophenoxy acetic acid, MCPA, and 2,4,5-trichlorophenoxy acetic acid) and similar acid herbicides (benzaton, dicamba, dichlorprop, and mecoprop) sulfonurea herbicides (chlorsulforon, metsulforon methyl, tribenuron methyl, and thifensulfuron methyl) triazine herbicides (methoxy-s-triazines, chloro-s-triazines, alkylthio-s-triazines) phenylurea herbicides (fenuron, monolinuron, and diuron), metabolites of the fungicide thiophanate-methyl (carbenazim and 2-aminobenzimidazole)... 

Methyl-4-chloro-phenoxy) propionic acid 0.05 M lithium acetate containing a-cyclodextrins UV,200nm 26... 

Methyl-4-chloro-phenoxy) propionic acid and 2-(2,4-dichlorophenoxy)-propionic acid 0.03 M lithium acetate containing heptakis-(2,6-di-0-methyl)-/S-CD UV, 200 nm 27... 

Ethoxy-, -chloro- and -phenoxy-pyridine 1-oxides give 2-hydroxypyridine 1-oxide, the oxide function surviving in these cases" . An unusual example is that of 2-carboxy-5-methoxycarbonylpyridine 1-oxide. With benzoyl chloride in dioxan this gives 6-hydroxynicotinic acid. However, with acetic anhydride or acetyl chloride, methyl 4-acetoxynicotinate results . 

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