Ethyl oxalacetate

The three-component reaction of sodium ethyl oxalacetate with ammonia or primary amines with an aromatic aldehyde in ethanol or acetic acid results in the... 

The synthesis of l-carbethoxy-2,3-dioxopyrrolizidine (cf. refs. 61 and 62) starting with d -pyrroline and ethyl oxalacetate has been reported.97... 

Several a-btomo-a,/3-olefinic ketones and esters have been prepared by an interesting cleavage of S-acyl or )3-carbethoxy-a-ketolactones. It is unnecessary to isolate the bromolactone. Bromination and cleavage take place readily at 0-20° over-all yields are 60-85%. The /6-acyl and /6-catbethoxy-a-ketolactones are prepared by aldol-type condensations of aldehydes with the active methylene groups of ethyl )3-acetyl-pyruvate, CHjCOCHjCOCO CjHs, and ethyl oxalacetate,... 

Method of manufacture phenylhydrazine p-sulfonic acid is condensed with sodium ethyl oxalacetate the product obtained from this reaction is then coupled with diazotized sulfanilic acid. 

Butyraldehyde added with vigorous stirring to a suspension of ethyl oxalacetate Na-enolate in abs. alcohol, whereby the temp, rises to ca. 40°, and worked up after 16 hrs. —a-keto-/ -carbethoxy-y-M-propyl-y-lactone (startg. m. f. 86). Y 71%. (F. e. s. H. Schinz and A. Rossi, Helv. 31,1953 (1948).)... 

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. 

This acetylpyridone diester 15 was conveniently synthesized in 60% yield by reacting acetoacetamide with ethoxy-methylene oxalacetic acid diethyl ester 14 in ethanol in the presence of sodium acetate (13). Compound 14 was prepared according to the procedure of R. G. Jones by condensing ethyl oxalacetate with ethyl orthoformate in the presence of acetic anhydride (14). It was found that purified compound 14 gave the best yield (60%) of acetylpyridone diester 15, but as a matter of convenience, crude 14 gave product 15 in up to 40% yield. Isolation of 15 was expedited by the precipitation of its sodium salt from the reaction mixture. 

The method of synthesis described for chloropyruvic acid is essentially that reported. This procedure affords the product in excellent yields from readily available materials by a short, convenient route. Other less acceptable methods involve chlorination of pyruvic acid with sulfur dichloride or hypochlorous acid and the treatment of ethyl chloro(l-hydroxyheptyl)- or (o -hydroxybenzyl)oxalacetate 7-lactone with 50% hydrochloric acid. ... 

Oxal-ither, oxalic ether (ethyl oxalate), -essigester, m. oxalacetic ester, -essigsaure, /, oxalacetic acid, -ester, m, oxalic ester (specif, ethyt oxalate),... 

These syntlieses give no indication as to the structure of aspartic acid, the constitutional formula of which is based upon Kolbe s work, that it is amino-succinic acid the only synthesis of aspartic acid which confirms this constitution appears to be that by Piutti in 1887. Sodium oxalacetic ester, prepared from oxalic ester and acetic ester in the presence of sodium ethylate —... 

It became of interest to see if we could obtain any indication of Schiff base formation with the polymer. Since spectroscopic probes would be obscured with the actual substrate, oxalacetate, because of the progress of the decarboxylation reaction (32), we have examined instead the spectra of oxalacetate-4-ethyl ester in solutions of the same modified poly-(ethylenimine) PEIQ—NH2. Such solutions develop a new absorption band at 290 nm. Furthermore, this band is essentially abolished if NaBH4 is added to the solution (Fig. 21). As is well known, NaBH4 reduces Schiff base linkages to amine groups.43-44... 

It has also been possible to confirm the presence of the reduction product of a Schiff base on the polymer by proton magnetic resonance. For this purpose we have used unmodified poly(ethylenimine), since it too catalyzes the decarboxylation of oxalacetate to its product, pyruvate. Unmodified polyethylenimine was mixed with oxalacetate-4-ethyl ester. One-half of this solution was treated with NaBH4 the second half was exposed to a similar environment but no NaBH4 was added. The borohydride-treated polymer exhibited a strong triplet in the nmr spectrum centered at 3.4 ppm upfield from the HOD resonance. This new feature would be expected from the terminal methyl protons of the oxalacetate ester attached to the polymer. Only a very weak triplet was found in the control sample not treated with borohydride. These observations are strong evidence for the formation of Schiff bases with the polymer primary amine groups. Evidently the mechanistic pathway for decarboxylation by the polymer catalyst is similar to that used enzymatically. 

Fig. 21. Changes in ultraviolet spectra on addition of NaBH4 to a mixture of oxalacetate-4-ethyl ester and PEIQ-NH2.

Tetracarboxy furan Condensation of ethyl sodio oxalacetate... 

Ethyl dnnamate occurs in small amounts in storax.1 It has been prepared by the action of ethyl alcohol on cinnamic acid in the presence of dry hydrochloric or sulfuric acid 2 by the distillation of the copper salt of the monoethyl ester of benzylidene oxalacetic acid3 and by the condensation of ethyl acetate and benzaldehyde in the presence of sodium.4 The method described in the procedure is a slight modification of the one originally described by Claisen.5... 

A route to hept-2-ulosonic acid derivatives is available by way of the reaction of 2,3 4,5-di-0-isopropylidene-L-arabinose and 2,4 3,5-di-0-ethylidene-L-xylose with ethyl nitrosoacetate. ° Isomerization of the intermediate nitroso derivatives with alcoholic sodium nitrite yielded the corresponding oximes, which can be deoximated with lead tetra-acetate in acetic acid. 3-Deoxy-D-manno-oct-2-ulosonic acid 5-(dihydrogen phosphate) and its D-gluco analogue have been obtained by base-catalysed condensation of o-arabinose 2-phosphate (obtained by way of phosphorylation of benzyl 3,4-0-isopropylidene-P-D-arabinopyrano-side) with oxalacetic and separation of the isomers by ion-exchange chromato-graphy. ... 

A soln. of 4-amino-3-hydroxy-5-methylacetophenone and the equivalent amount of diethyl oxalacetate refluxed 1 hr. ethyl 5-methyl-7-acetylbenz-l,4-oxazin-2-on-3-ylacetate. Y ca. 90%.—Because these benz-l,4-oxazin-2-ones crystallize well and can be cleaved by alkali, they are suitable for the separation of aminophenols and the identification of the o-isomers. Even isomeric o-aminophenols can be separated due to different reaction rates. F. e. s. A. Butenandt, E. Biekert, et al., B. 92, 2172 (1959). Condensed l,4-oxazin-2-ones may also be used for the identification of a-ketocarboxylic acid esters. E. s. B.94, 1664 (1961). 

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