Oxanilic acid

The method for chloroacetanilide soil metabolites in water determines concentrations of ethanesulfonic acid (ESA) and oxanilic acid (OXA) metabolites of alachlor, acetochlor, and metolachlor in surface water and groundwater samples by direct aqueous injection LC/MS/MS. After injection, compounds are separated by reversed-phase HPLC and introduced into the mass spectrometer with a TurboIonSpray atmospheric pressure ionization (API) interface. Using direct aqueous injection without prior SPE and/or concentration minimizes losses and greatly simplifies the analytical procedure. Standard addition experiments can be used to check for matrix effects. With multiple-reaction monitoring in the negative electrospray ionization mode, LC/MS/MS provides superior specificity and sensitivity compared with conventional liquid chromatography/mass spectrometry (LC/MS) or liquid chromatography/ultraviolet detection (LC/UV), and the need for a confirmatory method is eliminated. In summary,... 

Acetic acid, [(ethoxymethyl)(2-ethyl-6-methylphenyl)amino]oxo-, sodium salt, should be >95% pure (EMA-producing oxanilic acid metabolite, referred to from this point as Metabolite I)... 

Limits of detection for each of the six soil metabolites in surface water and ground-water were determined by using an estimate of variability for the 0.25 pgL fortifications from samples analyzed along with hundreds of surface water and groundwater sets during the years 1999-2001. During these years, the estimated LODs were below 0.1 ug for acetochlor sulfonic acid, acetochlor oxanilic acid, alachlor oxanilic acid, metolachlor sulfonic acid, and metolachlor oxanilic acid and about 0.1 igL for alachlor sulfonic acid. If the actual concentration of an analyte is at this detection limit or greater, there is at least a 95% chance of detection. 

LOQs for each of the six soil metabolites in surface water and groundwaters were determined using analytical results (not corrected for background) of samples fortified at the lowest fortification level, 0.25 igL during the analysis in years 1999-2001. The calculated LOQs for acetochlor oxanilic acid, metolachlor sulfonic acid and metolachlor oxanilic acid are below 0.25 ig L. The calculated LOQs for acetochlor sulfonic acid, alachlor sulfonic acid, and alachlor oxanilic acid are below 0.10 igL. If the true concentration of an analyte is at the LQQ or greater, the standard error of individual measured concentration values relative to the true concentration is at most 10%. 

This study will provide fundamental information on the effect of stereoisomerism on the environmental fate of a widely used chloroacetanilide herbicide, metolachlor. Metolachlor is classified as a potential carcinogen and is the second most extensively used herbicide in the United States (7). Biological dechlorination of metolachlor leads to the formation of more polar metabolites (8), metolachlor oxanilic acid (OXA), and metolachlor ethanesulfonic acid (ESA) (Figure 3). Metolachlor OXA and metolachlor ESA are found at higher concentrations and are more frequently detected in surface and ground water than their parent compound (9). 

Analytical Methods Development. A solid-phase extraction (SPE) method that will isolate and fractionate metolachlor and its oxanilic acid (OXA) and ethanesulfonic acid (ESA) metabolites from soil and water will be developed. The SPE method will be used... 

N-(2-Benzoyl-4-chlorophenyl)oxanilic acid ethyl ester. Acetic acid,... 

Azidooxonilic Acid. See Oxanylaziae under Oxanilic Acid and Beil 12, 772... 

Chromium tetraphenyl hydrogen oxanilate,1 (C6H6)4Cr.02C. C0.NH.C6H5.C6H5.NH.C0.C02H, from the pentaphenyl base and oxanilic acid, yields orange-red needles, M.pt. 1-11° C., very soluble in methyl alcohol, pyridine or chloroform, sparingly soluble in ethyl alcohol, insoluble in benzene. 

The ethyl 3-(lH-tetrazol-5-yl)oxanilate (5.0 g), was dissolved in 35 ml of ethanol and 100 ml of 0.5 N sodium hydroxide was dropwise added thereto under water cooling. After the dropwise addition, the reaction temperature was slowly raised up to room temperature and under such condition, the reaction was carried out for 3 h. This solution was dropwise added to 70 ml of 4 N hydrochloric acid at room temperature. Thereafter, the solution was stirred for 1 h and crystals separated out from the solution was filtered off. The resultant crystals were washed with water and 3.9 g of 3-(lH-tetrazol-5-yl)oxanilic acid was recovered (yield 87.4%), melting point 241°-243°C (dec. recrystallized from isopropyl). 

Oxalyl chloride (12.0 g) was dissolved in 50 ml of anhydrous dimethoxyethane. To this solution a solution of 3-(lH-tetrazol-5-yl)aniline (5.0 g) in 250 ml of anhydrous dimethoxyethane was dropwise added over 3 h at room temperature while stirring. Insolubles were removed by filtering the solution, then 50 ml of water was gradually added to the reaction mixture under ice cooling and stirring was continued for 1 h at room temperature. Then, 500 ml of ethyl acetate was added thereto to carry out extraction, the extract was washed with water, dried over anhydrous sodium sulfate and then the solvent was distilled off to obtain 5.4 g of the 3-(lH-tetrazol-5- yl)oxanilic acid (yield 74.8%), melting point 241°-243°C (dec. recrystallized from isopropyl). 

Scarfe, G.B., Wilson, I.D., Wame, M.A., Holmes, E., Nicholson, J.K., and Lindon, J.C., Structure-metabolism relationships of substituted anilines prediction of N-acetylation and N-oxanilic acid formation using computational chemistry, Xenobiotica, 32, 267-277, 2002. 

Carboxin was much more readily photodegraded than oxycarboxin in pure water. The oxidation of the sulphur atom yielded the sulphoxide Va and the subsequent loss of the heterocyclic ring produced the oxanilic acid Vb (see Scheme 6). Humic substances enhanced the phototransformation of both fungicides. For carboxin, this enhancement is possibly related to the presence of the sulphur atom that might be oxidized by singlet oxygen or other photo-oxidants. 

A compound having a carboxylic acid and an amino (or imino) group within the molecule can yield cyclic oligomers by intermolecular twofold amide formation. For example, oxanilic acid has been dimerized23 in the presence of thionyl chloride to give the tetraketopiperazine (13). Self-condensation24 of anthranilic acid on refluxing in xylene... 

This quantity in gram-molecules per litre is 0 0176 X 0 416 = 0 00732, and represents saturation with the undissociated salt, and remains the same on addition of the oxanilic acid, only the dissociated quantity being affected. Calling G the total concentration, we have in solution... 

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