Ethyl oxaloacetate

Preparation o the key intermediate for the chloroquinoline series starts with Shiff base formation of metachloroaniline with ethyl oxaloacetate (66). Heating of the intermediate leads to cyclization into the aromatic ring and consequent formation of the quinoline ring (67). Saponification of the ester to the acid... 

Synthesis of nl -asparagine starting with ethyl oxaloacetate Cocker, J. Chem. Soc, 1940, 1489. Configuration Timmermans el al. Butt. Soc. Chim. Belg. 40, 33 (1939). Structure Steward, Thompson, Nature 169, 739 (1952). 

Oxoglutaric acid (2-oxopentane-l,5-dioic, a-ketoglutaric acid) [328-50-7] M 146.1, m 114 , 115-117 , (pK ,( see oxaloacetic acid above). Crystd repeatedly from Me2CO/ benzene, EtOAc or ethyl propionate. 

The second method of preparing of 4,7-dichloroquinoline (37.1.1.1) consists of reacting 3-chloroaniline with the diethyl ester of oxaloacetic acid in the presence of acetic acid to give the corresponding enamine (37.1.1.8), which when heated to 250 °C undergoes heterocyclization to the ethyl ester of 7-chloro-4-hydrozyquinolin-2-carboxylic acid (37.1.1.9) accompanied with a small amount of 5-chloro-4-hydroxyquinolin-2-carboxylic acid... 

The reaction of aroylhydrazines with DMAD gives rise to the hydrazones of oxaloacetic ester, which undergo thermal transformation to the corresponding diaroylhydrazines. b. Hydrazones. Ethyl l,3,5-triphenylpyrazole-4-carboxylate has been reported to be formed in the reaction of benzaldehyde phenylhydrazone with ethyl phenylpropiolate. In a detailed investigation, George and co-workers have shown that aldehyde phenylhydrazones react with DMAD, yielding a mixture of pyrazoles and pyrazolines. Thus, in the reaction of benzaldehyde phenylhydrazone with DMAD, products such as dimethyl l,3-diphenylpyrazoline-4,5-dicarboxylate (129), dimethyl... 

Condensation of 3-amino-2-(methylamino)pyridine 647 with diethyl 2-oxomalonate in boiling ethanol afforded 2-carbethoxy-4-methylpyrido[2,3- ]pyrazin-3(4//)-one 213 <1996JHC1737>. On the other hand, condensation of 647 with diethyl oxaloacetate gave ethyl [2(l//)-oxopyrido[2,3- ]pyrazine-3(4//)-ylidene]carboxylate 648 in addition to the formation of pyridodiazepine 649 as a by-product <1996JHC1737>. However, the condensation of 647 with diethyl 2-oxoadipate gave the 2-ethoxycarbonylpropyl analogue 650 (Scheme 30) <1994FA259>. 

Oxaloacetic acid [328-42-7] M 132.1, m 160°(decarboxylates). Crystd from boiling ethyl acetate, or from hot acetone by addition of hot benzene. 

When an a-chloroaldehyde or an a-chloroketone is condensed with a /3-ketoester, in the presence of aqueous base, a furan is produced bearing an ester substituent at the /3-position. It is thought that the reaction is of the aldol type intermediate dihydrofurans (256) have been isolated in certain cases (Scheme 70) (74BSF519). The condensation of ethyl bromopyru-vate and sodium oxaloacetate follows a similar mechanism (54JOC1671). The one-pot synthesis of 2,4,5-trisubstituted furans (257) from ketones and ethyl 3,4-dibromo-2-butenoate is a useful addition to a well known route (80S52). The analogous reaction of cyclic /3-diketones, i.e. cyclohexane-1,3-dione and 5,5-dimethylcyclohexane-l,3-dione, results in the formation of the condensed furans (258) and (259). These reactions are preformed either in ethanol with sodium ethoxide or in DMF with potassium carbonate. 

Decarboxylation of /3-ketodicarboxylic acids - approximations to the overall rate expression deduced from the mechanism, 341-342 Decarboxylation of oxaloacetic acid - contributions to the overall rate, 342-343 Glycine ethyl ester, metal ion catalysed hydrolysis, formulation of the rate expression, 344-346... 

A convenient synthesis of pyridazine-3,4-dicarboxylic acid based on [4 + 2] cycloaddition of an electron deficient diazadiene has been developed (Scheme 102) and carried out on a molar scale. The azadiene is generated in situ from the precursor (124) (prepared from diethyl oxaloacetate and methyl carbazate followed by chlorination with sulfuryl chloride) and trapped with ethyl vinyl ether. The regiospecific cycloaddition gives the tetrahydropyridazine (125) as a mixture of cis and trans isomers which, with bromine in acetic acid, are transformed into diethyl pyridazine-3,4-dicar-boxylate. Saponification gives the diacid in an overall yield of 52% <90JHC579>. In a similar approach from the readily available ethyl 2-chloro-3-oxobutanoate, an efficient route to ethyl 3-methylpyridazine-4-carboxylate has been developed which gives the product in 56% overall yield. This route is claimed to be a practical alternative to the radical ethoxycarbonylation of pyridazines <91JHC1043>. 

Ethyl Oxalacetate. Oxobutanedioie add diethyl ester diethyl oxalacetate oxaloacetic ester. C Hl2Os mol wt 188.18. C 51,06%, H 6,43%. O 42.51%. C OOCCH CO-COOCjHj. Obtained by the action of sodium on a mixture of ethyl oxalate and ethyl acetate. 

Ethyl 2-(aminomethylene)oxaloacetate 1089 18% Anhydrous alcoholic ammonia solution (26 g, 0.27 mole of NH3) is added in one portion to a stirred solution of 2-(ethoxymethylene)-oxaloacetate (61 g, 0.25 mole) in dry ether (250 ml) that is cooled in ice-salt. The mixture is shaken and set aside for 20 h in a closed vessel. The gelatinous precipitate is then filtered off and washed thoroughly with dry ether. Evaporating the combined filtrates in a vacuum affords a syrup, which soon crystallizes [45-49 g, 84-91% m.p. 68-69° (from ether-light petroleum)]. 

In the oxidative deamination reaction, the enzyme was active toward N-[l-D-(carboxyl)ethyl]-L-methionine, N-[l-D-(carboxyl)ethyl]-L-phenylalanine, etc. The substrate specificity for amino donors of ODH in the reductive secondary amine-forming reaction was examined with pyruvate as a fixed amino acceptor [15,24]. The enzyme utilized L-norvaline, L-2-aminobutyric acid, L-norleucine, P-chloro-L-alanine, o-acetyl-L-serine, L-methionine, L-isoleucine, L-valine, L-phenylalanine, L-homophenylalanine, L-leucine, L-alanine, etc. 3-Aminobutyric acid and L-phenylalaninol also acted as substrates for the enzyme. Other amino compounds, such as P-amino acids, amino acid esters and amides, amino alcohols, organic amines, hydroxylamines, and hydrazines, were inactive as substrates. Pyruvate, oxaloacetate, glyoxylate, and a-ketobutyrate were good amino acceptors. We named the enzyme as opine... 

Ethyl picolinate failed to undergo condensation with diethyl oxaloacetate (XI-46) (using Claisen conditions) to give the desired product XI-47. ... 

Diethyl oxaloacetate, condensation with ethyl picollnate, 343... 

Numerous CH insertion reactions of isocyanates involve substrates with a CH2CO group. For example, dialkyl malonates, malonitrile , ethyl cyanoacetate and oxaloacetic esters react with alkyl and aryl isocyanates at room temperature, in the presence of triethylamine, to give products resulting from insertion into the activated C-H bond as... 

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