Hydroxy acids, detection identification

When male F-344 rats were injected with NNN-2 -14c, 75-95% of the dose was excreted in the 48 hr urine. In one experiment, the urine was collected in vessels containing DNP reagent. However, the DNPs of 4-hydroxy-l-(3-pyridyl)-l-butanone and 4-hy-droxy-4-C3-pyridy1)butanal were not detected. Since this was likely due to further oxidation in vivo, methods were developed for isolation of their probable oxidation products. This resulted in identification of the lactone, 5- C3-pyridyl)—tetrahydrofuran-2-one (1-2%), the keto acid, 4-(3-pyridyl).-4-oxobutyric acid (1-2%) and the hydroxy acid, 4-(3-pyridyl)-4-hydroxybutyric acid (26-40%) as urinary metabolites. These metabolites resulted. 

Unknown compounds are detected frequently, and laboratories eventually develop some level of comfort in recognizing them as artifacts that are not significant clinically, at least for the purpose of ruling out a possible inborn error of metabolism [21]. However, there are instances when an unknown compound is found in multiple specimens from the same patient and cannot be associated with ongoing drug and known dietary intake. This was the set of circumstances that led to the identification of 2-octenylsuccinic acid as the compound referred to by some laboratories as pseudo-orotic acid [11, 18]. On the other hand, the spectrum shown in Fig. 3.1.10, tentatively identified as 4-hydroxy 2-hexenoic acid by GC-MS/MS, belongs to a compound that appears in the urine of patients with disorders of propionate me-... 

As shown in our previous communication (32), most informative was the identification of large amounts of p-hydroxy- and 3,4-dihydroxyben-zoic acids in the oxidation products of low-rank coals (these coals are listed as Samples I and 2 in this chapter). These are regarded as lignin oxidation products. In this study we have found that, while no o- and m-hydroxybenzoic acids were found in the oxidation products of Samples I and 2, all three isomers were identified in small amounts in other rank bituminous coals (Samples 3, 5, 6). From Sample 3, 3,4-dihydroxyben-zoic acid also was isolated in small amounts, however, this compound was not detected in the oxidation product of other bituminous coals (Samples 4, 5, and 6). 

Krepelka et al. (84) described the synthesis and identification of some 1S+ 2-substitution derivatives of 5-(4-oxo-6-hydroxy-3,4-dihydro-5-pyrimidinyl) pentanoic acid using silica gel plates in the system 1-propanol-25% ammonia-water(7 l 2) and UV detection at 254 nm,... 

Hydroxamic acid gives a strong color with ferric chloride. This reaction is suitable for the detection of aldehydes in the presence of ketones. Aromatic / -hydroxyaldehydes, / -aminobenzaldehyde, vanillin, / -dimethyl-aminobenzaldehyde, salicylaldehyde, and aliphatic aldehydes with a hydroxy group in the y-position do not react. A positive reaction is observed with benzyl ketones in strongly alkaline media. It is necessary, therefore, to keep the mixture distinctly but not excessively alkaline. This reaction can be utilized for the separation of aldehydes from their mixture with ketones by converting the acid to its insoluble copper salt. Paper chromatography can be used for the identification of aldehydes in mixtures (41). 

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