Oxobutyrates

L-3-metliylvaline 3, 3-dimethyl-2-oxobutyric acid + Asp transaminase Cryptococcus leurentii 197... 

Majima et al. prepared ethyl y-(3-indolyl)-y-oxobut3rrate (250) in a similar manner by the condensation of the indole Grignard reagent with -ethoxycarboiiylpropionyl chloride.Methyl y-(3-indolyl)-y-oxobutyrate (251) has been obtained by the action of mcthoxycarbonylpropionyl chloride on indole magnesium iodide in ether. Ballantine et al. prepared methyl y-(5-methoxy-3-... 

Chemical Name 3 chloro-4-cyclohexyl-a-oxo-ben2enebutanoic acid Common Name 4-(4 cvclohexvl-3-chlorophenyl)-4 oxobutyric acid Structural Formula ... 

Acylation of 270 with certain cyclic anhydrides 433 in acetic acid affords 4-oxobutyric acid derivatives 434. Cyclocondensation of these acids with acetic anhydride gives pyridazino[l,2- ]indazole-6,9,ll-triones 435 (Scheme 70) <2003MI1>. 

Diazo-1,3-dicarbonyl compounds such as alkyl 2-diazo-3-oxobutyrates 57a, b and 3-diazo-2,4-pentanedione 57 c behave like the diazopyruvate 56, as far as their carbenoid cycloaddition behavior is concerned 114,130). 

From the copper-catalyzed reaction of methyl 2-diazo-3-oxobutyrate 57 a with Z-3-methoxystyrene, dihydrofuran 59 (formed with retention of olefin configuration) and butadienol 60 result130). Such an acyclic by-product also occurs when benzofuran is the cycloaddition partner. In that case, however, regioisomers 61 and 62, arising from the connection of the former diazo carbon with either the 2- or 3-position of the heterocycle, are obtained similarly, two isomeric dihydrofurans 63 and 64 are formed under Cu(hfacac)2 catalysis130). 

The copper-catalyzed decomposition of methyl 2-diazo-3-oxobutyrate 57 a in the presence of aldehydes gives ready excess to l,3-dioxole-4-carboxylates 275). Copper(II)... 

Fig. 8.1 Proposed synthetic pathways for dimethylsulfoniopropionate from methionine for three algal and plant species. DMSHB 4-dimethylsulfio-2-hydroxy-butyrate, MTHB 4-methylthio-2-hydroxybutyrate, MTOB 4-methylthio-2-oxobutyrate, SMM S-methylmethionine...

A mechanistic study of acetophenone keto-enol tautomerism has been reported, and intramolecular and external factors determining the enol-enol equilibria in the cw-enol forms of 1,3-dicarbonyl compounds have been analysed. The effects of substituents, solvents, concentration, and temperature on the tautomerization of ethyl 3-oxobutyrate and its 2-alkyl derivatives have been studied, and the keto-enol tautomerism of mono-substituted phenylpyruvic acids has been investigated. Equilibrium constants have been measured for the keto-enol tautomers of 2-, 3- and 4-phenylacetylpyridines in aqueous solution. A procedure has been developed for the acylation of phosphoryl- and thiophosphoryl-acetonitriles under phase-transfer catalysis conditions, and the keto-enol tautomerism of the resulting phosphoryl(thiophosphoryl)-substituted acylacetonitriles has been studied. The equilibrium (388) (389) has been catalysed by acid, base and by iron(III). Whereas... 

Acrylonitrile, 1,1-Dichloroethylene, Ethyl acrylate. Methyl acrylate. Methyl methacrylate Y-Hydroxy-y-o-hydroxyphenyl-a-oxobutyrate, see Carbaryl... 

This enzyme [EC 1.2.7.2], also known as 2-oxobutyrate synthase, catalyzes the reaction of o -ketobutyrate (or,... 

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. 

Scheme 2. Enantio-differentiating hydrogenation of methyl 2-methyl-3-oxobutyrate.

Enantio-Differentiating Hydrogenation of Methyl 2-Methyl-3-oxobutyrate (8) with Various Modified Nickel Catalysts ... 

Ketoacid standard (3-methyl-2-oxobutyric acid, 2-ketoisovaleric) mix 50 mg in 25 ml (2 mg/ml) deionized water. Store the solution at 4°C. 

S phosphoenolpyruvate -I- histidine-containing protein <1-9, 13-15> (<1,6> in a first reaction step phosphate is transferred to the N-3 position of the imidazole ring of histidine [4, 9, 13] <6> in a second reaction step phosphate is transferred to the N-1 position of the imidazole ring of the histidine containing-protein (i.e. HPr), the phospho group of the intermediate phospho-enzyme I can also be transferred to pyruvate or 2-oxobutyrate... 

The isomeric l,2,4-triazin-5-ones also have herbicidal activity, and of these the 4-amino compounds stand out. Metribuzin (3) and metamitron (4) (68SAP6804409) possess excellent selectivity, the former being manufactured on a very large scale. Metribuzin can be synthesized from 3,3-dimethyl-2-oxobutyric acid (Scheme 3). 

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