Oxamic acid

Following slow dissolution into the soil solution, oxamide undergoes stepwise hydrolysis to Hberate ammonia. Oxamic acid is formed in the first... 

Oxamidsaure, Oxaminsaure, /. oxamic acid, Oxathyl-. hydroxyethyl-. 

N-Acetylation of Kasugamycinic Acid (9a). A solution of kasugamycinic acid (225 mg.) dissolved in 10 ml. of water was treated with acetic anhydride (0.3 ml.) under cooling sodium bicarbonate was used to keep the pH 7.2 and stirring continued for 30 minutes. The reaction product was passed through Dowex 50W-X2 (H form) and the column was washed with water. The combined filtrate was subjected to lyophilization to afford 234 mg. of a crude N-acetyl derivative. Its infrared spectrum showed strong absorptions at 1740 cm-1 characteristic of oxamic acid group. The N-acetyl derivative (178 mg.) was treated with 40 ml. 

Thiazolo[2,3-c][l,2,4]triazines 658 were prepared (84LA1302) regio-specifically by cyclizing 2-hydrazono-2-thiazoline 659 with glyoxylic acid or ester. They had herbicidal activity. Condensation of 659 with oxamic acid ethyl ester gave hydrazide 660, which was cyclized with sodium... 

Oxamic Acid Azide (Azido Oxamate, Oxamido-azide, Oxamidsaureazid or Oxalsaure-amid-azid in Ger). H2N.CO.CO.N3, mw 114.02, N 49.11%, OB to C02 —42.09%, crystals from acet+petr eth mp, explds violently ca 115° or on rubbing. Can be prepd by treating the hydrazide of oxamic acid with Na nitrite in w Refs 1) Beil 2, (244) 2) T. Curtius, JPraktChem [2] 91, 426 (1915) 3) Urbanski 3... 

CnHijNjO, 80573-04-2) see Balsalazide sodium DL-(l-carboxyethyl)oxamic acid diethyl ester (C7H15NO5 23460-73-3) see Pyridoxine... 

A/-Ethoxymethyl-A/-(2-ethyl-6-methylphenyl) oxamic acid, sodium salt... 

Oxamic acid 26 and AT-hydroxyoxamic acid 27 derivatives were disclosed by the Boehringer Ingelheim group as moderately active Lck SH2 domain antagonists [119,130]. 

Fig. 11.7. The two pathways of dechlorination of chloramphenicol (11.39). Cytochrome P450 catalyzed oxidation to yield the oxamic acid derivative (11.40), and hydrolytic dechlorination to yield both oxamic acid (11.40) and primary alcohol (11.41) metabolites [75].

In contrast to oxidative dechlorination, the hydrolytic dechlorination of chloramphenicol replaces a Cl-atom with a OH group to yield a (monochlo-ro)hydroxyacetamido intermediate. The latter, like the dichloro analogue, also eliminates HC1, but the product is an aldehyde that is far less reactive than the oxamoyl chloride intermediate. Chloramphenicol-aldehyde undergoes the usual biotransformation of aldehydes, namely reduction to the primary alcohol 11.41 and dehydrogenation to the oxamic acid derivative 11.40 (Fig. 11.7). 

In conclusion, the oxamic acid derivative is produced by two distinct metabolic pathways, namely by oxidative and hydrolytic dechlorinations. In contrast, the primary alcohol metabolite 11.41 can be produced only by hydrolytic dechlorination and is, thus, an unambiguous marker of this pathway. The alcohol 11.41 is a known urinary metabolite of chloramphenicol in humans. 

A number of published papers have included SAR details for several series of compounds, including the phenoxazines (89) [485], naphthoylvalerohydr-oxamic acids represented by (115) [486] and the ICI series represented by (145) and (146) [487]. A full paper dealing with the 4-hydroxythiazoles represented by (74) indicated that only compounds existing in the enolic form were active 5-unsubstituted cases and also 5,5-disubstituted cases (which are ketonic) were inactive [488]. Acylation of the hydroxyl was acceptable for good activity. No strong correlation of aryl substitution with potency... 

Chemical/Physical. The gas-phase reaction of ozone with pyridine in synthetic air at 23 °C yielded a nitrated salt having the formula [CeHsNHJ NOs (Atkinson et al., 1987). Ozonation of pyridine in aqueous solutions at 25 °C was studied with and without the addition of ferf-butyl alcohol (20 mM) as a radical scavenger. With tert-hniyX alcohol, ozonation of pyridine yielded mainly pyridine W-oxide (80% yield), which was very stable towards ozone. Without terf-butyl alcohol, the heterocyclic ring is rapidly cleaved forming ammonia, nitrate, and the amidic compound W-formyl oxamic acid (Andreozzi et al., 1991). 

Oxadiazonphenol, see Oxadiazon Oxalic acid, see Acetic acid, 2-Chlorophenol, Cyclohexene, 2,4-D, 2,4-Dinitrophenol, 1,4-Dioxane, Glycine. 2-Methylphenol, Naphthalene, 4-Nitroaniline, 4-Nitrophenol, Parathion, Phenol, Picloram. 2,4,5-T Oxamic acid, see Acetamide 1 -Oxa-2-oxocycloheptane, see Cyclohexane Oxindole, see Indole... 

CoHijCbNOs 2-(2,4-Dichlorophenoxy)-A -(4- metiiylplienyl)acetohy[Pg.542]

Ethyl thioamidooxalate Oxamic acid, 2-thio-, ethyl ester (8) Acetic acid, aminothioxo-, ethyl ester (9) (16982-21-1)... 

The reaction protocol was further extended to the concise synthesis of poly-oxamic acid, the unique polyhydroxyamino acid side-chain moiety of the antifungal polyoxin antibiotics (63). Treatment of the template 205 under standard thermal cycloaddition conditions with (5)-glyceraldehyde acetonide led to the formation of a single diastereoisomer 208 in 53% yield. Subsequent template removal released polyoxamic acid 209 in essentially quantitative yield. This represents a matched system, with the mismatched system leading to more complex reaction mixtures (Scheme 3.70). 

Azidccxsmste. See Qxamylazide under Oxamic Acid and Beil 2, (244)... 

Anodic oxidation of 6- and 7-pteridone, using electrolysis at a controlled potential, gave pteridine-6,7-dione in 95-100% yield.409 Under controlled-potential electrolysis conditions pteridine-6,7-dione is oxidized to the bridgehead diol, which undergoes rearrangement, further oxidation, and hydrolysis, yielding tetraketopiperazine, oxamide, urea, oxamic acid, ammonia, formaldehyde, formic acid, and C02-... 

Carboxyaxanilic Acid, Same as Carboxyphenyl-oxamic Acid... 

NH2OCCOOH (c). Matignon1 and Stohmann and Haussmann1-2 found 128.6 and 132.6, respectively, for the heat of combustion of solid oxamic acid. 

NH2OCCOOH (aq.). Matignon1 measured the heat of solution of solid oxamic acid. 

The NCA 138 represents the amino-protected and carboxy-activated form of poly-oxamic acid 140, the hydroxylic amino acid portion of the antifungal family of polyoxins 139, Fig. 8. Other polyolic NCAs such as 141,142, and 143, Fig. 9, have also been prepared from the corresponding a-hydroxy p-lactams with equal success [123, 124]. 

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