Pyruvic oxime

Castignetti, D., and Gunner, H. B. (1981). Nitrite and nitrate synthesis from pyruvate oxime by an Alcaligenes sp. Curr. Microbiol. 5, 379-384. 

The hydrolytic products are benzyl alcohol and the corresponding enol phosphonate produced through carboxyl group participation. In the presence of hydroxylamine the products are diverted to benzyl phenylphosphonate and pyruvate oxime hydroxamate. These experimental results contrast markedly with those observed for the phosphoacetoin system. A simple explanation for the formation of benzyl phenylphosphonic acid is generation of the penta-covalent species (47)... 

Intramolecular nucleophilic substitution of electrogenerated phenoxonium ions has been investigated . In connection with naturally occurring bromo compounds, methyl 3,5-dibromo-4-hydroxyphenyl pyruvate oxime (98) was subjected to anodic oxidation (-1-1.3 V Vi. SCE 2.1 Fmol ) in MeOH to afford spiro-isoxazole 99 in almost quantitative yield . Methyl 3-bromo-4-hydroxyphenyl pyruvate oxime (100) was also electrolyzed under similar conditions to give three compounds 101, 102 and 103 in 34, 14 and 17% yields, respectively. The latter two products are formed by C—O and C—C radical couplings, respectively, as shown in Scheme 19 °. 

Fig. 3.6. A schematic presentation of nitrite formation from hydroxylamine in the cell of Alcaligenes faecalis. Circled numbers 1, ammonia monooxygenase 2, pyruvic oxime...

Alcaligenes faecalis has a hydroxylamine-oxidizing enzyme which differs from the enzyme of other heterotrophic nitrifying bacteria. In this bacterium, hydroxylamine is oxidized through pyruvic oxime (Fig. 3.6). Pyruvic acid derived from lactate, succinate, and other carboxylates reacts nonenzymatically with hydroxylamine formed from ammonia to form pyruvic oxime. This compound is oxidized to nitrite and pyruvic acid by the catalysis of pyruvic oxime dioxygenase (Ono et al., 1996, 1999). 

Previously, a heterotrophic nitrifier, Achromobacter sp. was found to oxidize pyruvic oxime externally added to form nitrite (Quastel et al., 1952). However, as pyruvic oxime does not occur in Nature (Lang and Jagnow, 1986), the nitrification mechanism in which pyruvic oxime has to be acquired from the outside of the bacterial cells was denied. Ono et al. (1996) have shown that pyruvic oxime is formed inside the bacterial cells. Thus, an oxidation mechanism of hydroxylamine to nitrite in a heterotrophic nitrifier has been elucidated. 

Castignetti D, Petithory JR, Hollocher TC (1983) Pathway of oxidation of pyruvic oxime by a heterotrophic nitrifier of the genus Alcaligenes evidence against hydrolysis to pyruvate and hydroxylamine. Arch Biochem Biophys 224 587-593 Caughey WS (1971) Structure-function relationships in cytochrome c oxidase and other hemo-proteins. Adv Chem Ser 100 248-269... 

Ono Y, Enokiya A, Masuko D, Shoji K, Yamanaka T (1999) Pyruvic oxime dioxygenase from the heterotrophic nitrifier Alcaligenes faecalis purification, and molecular and enzymatic properties. Plant Cell Physiol 40 47-52... 

Ono Y, Makino N, Hoshino Y, Shoji K, Yamanaka T (1996) An iron dioxygenase from Alcaligenes faecalis catalyzing the oxidation of pyruvic oxime to nitrite. FEMS Microbiol Lett 139 103-108... 

Quastel JH, Scholefield PG, Stevenson JW (1952) Oxidation of pyruvic oxime by soil organisms. Biochem J 51 278-284... 

The use of the 4tt diene participation of vinylnitroso compounds in Diels-Alder reactions in the preparation of aryl pyruvate oximes,76a c e 8>h amino acids,76a,c 8 y-hydroxynitriles,76ad 8 y-lactones,76dg pyridine N-ox-ides,76f and pyrroles77 is summarized in Scheme 9-III. The intramolecular Diels-Alder reactions of in situ generated and unactivated vinylnitroso compounds have been shown to proceed readily employing electron-rich olefins, and the course of the reaction has been shown to proceed preferentially through an endo transition state [Eq. (36)].79... 

Glyoxylic oxime 19 Ethylmalonic 34 4-Hydroxyphenylacetic pyruvic oxime... 

Isonitrosoacetone (unfi-pyruvic aldehyde-l-oxime) [31915-82-9] M 87.1, m 69". Crystd from ether/pet ether or CCI4. 

Mn02, hexane or CH2CI2, it, 70-92% yield. " The oximes of pyruvates and O-alkyl oximes are not cleaved under these conditions. 

If, for example, the reaction at pH 7 between pyruvate anion (70) and hydroxylamine, NH2OH, is followed by monitoring the infra-red spectrum of the reaction mixture, then the absorption characteristic of C=0 (vmax 1710 cm-1)—in the starting material (70)—is found to disappear completely before any absorption characteristic of C=N (vmax 1400 cm-1)—in the product oxime (71)—appears at all. Clearly an intermediate must thus be formed, and it seems probable that this is a carbinolamine (72 such a species has actually been detected by n.m.r. spectroscopy, in the reaction of MeCHO with NH2OH) ... 

Nitrophenyl)-2-hydroxyiminopropanoic acid ( -N it rophcnyl pyruvic acid oxime)... 

Gronowitz adapted this technology to one-pot syntheses of indole-3-acetic acids and indole-3-pyruvic acid oxime ethers from A-BOC protected o-iodoanilines [328, 329]. Rawal employed the Pd-catalyzed cyclization of A-(o-bromoallyl)anilines to afford 4- and 6-hydroxyindoles, and a 4,6-dihydroxyindole [330], and Yang and co-workers have used a similar cyclization to prepare 8-carbolines 287 and 288 as illustrated by the two examples shown [331]. The apparent extraneous methyl group in 288 is derived from triethylamine. 

The second example was the pyruvate decarboxylase catalyzed formation of (ll )-l-hydroxy-l-phenyl-2-propanone (PAC) with benzaldehyde as substrate (Fig. 5 a) [64]. This second reaction shows one potential limitation of this method. Some compounds are too volatile for direct measurement by MALDl mass spectrometry or they do not ionize directly due to their nonpolar character. In this case, these compounds have to be derivatized prior to their measurement in order to reduce their volatihty and to introduce ionizable functions. This is, however, often very easy using well estabhshed quantitative reactions, e.g., formation of oximes from aldehydes and sugars (Fig. 5b). 

Fig. 5. a Pyruvate decarboxylase catalyzed formation of (lJl)-l-hydroxy-l-phenyl-2-pro-panone (PAG) using benzaldehyde (BzA) as substrate, b Derivatization of benzaldehyde by formation of an oxime... 

Recently Benkovic and Schrayl28b and Clark and Kirby,26c have investigated the hydrolysis of dibenzylphosphoenolpyruvic acid and mono-benzylphospho-enolpyruvic acid which proceed via stepwise loss of benzyl alcohol (90%) and the concomitant formation of minor amounts (10%) of dibenzylphosphate and monobenzylphosphate, respectively. The pH-rate profiles for release of benzyl alcohol reveal that the hydrolytically reactive species must involve a protonated carboxyl group or its kinetic equivalent. In the presence of hydroxylamine the course of the reaction for the dibenzyl ester is diverted to the formation of dibenzyl phosphate (98%) and pyruvic acid oxime hydroxamate but remains unchanged for the monobenzyl ester except for production of pyruvic acid oxime hydroxamate. The latter presumably arises from phosphoenolpyruvate hydroxamate. These facts were rationalized according to scheme (44) for the dibenzyl ester, viz. 

Reaction of benzo[6]thiophene-2-carboxaldehyde with pyruvic acid yields the keto acid (321), the oxime of which gives a-amino-y-(2-benzo[6]thienyl)butyric acid (322) on catalytic hydrogenation, and j9-(2-benzo[6]thienyl)acrylonitrile on treatment with acetic anhydride the latter yields 8-(2-benzo[6]thienyl)acrylic acid on hydro-... 

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