Ethyl oxamate

Works on the oxidation of uric acid has unequivocally established the triazine structure > ° (9) of oxonic acid. This is further confirmed by the straightforward synthesis described by Piskala and Gut. ° The reaction of biuret (11) with potassium ethyloxalate yielded a potassium salt (24), that with ethyl oxamate, the amide of oxonic acid (25). Both these compounds were converted to 5-azauracil. An analogous reaction with diethyloxalate which should produce an ester of oxonic acid resulted in a mixture of urethane and parabanic acid, however. 

Theoretical evidence for the thermal decomposition mechanism for ethyl oxam-ate, ethyl oxanilate, and ethyl A,A-dimethyl oxamate have been provided.27 Ethyl oxamate and ethyl oxanilate undergo rapid decarbonylation to give the corresponding carbamates. Ethyl A,lV-dimethyloxamate elimination reaction yields in one step, through a six-membered cyclic transition state, dimethyloxamic acid and ethylene gas. 

The gas-phase elimination kinetics of ethyl oxamate, ethyl N,N-dimethyloxamate and ethyl oxanilate have been determined in a static reactor system, seasoned with allyl bromide and in the presence of a free radical inhibitor.12 These reactions are homogeneous, unimolecular and appear to proceed through moderately polar cyclic transition states. 

Adachi and Sato (483) have prepared six dihydroxypyrazines (103, R and R = H, Me, Ph) by condensation of a-aminoketals (100) with ethyl oxamate (101) to oxamoylamino ketones (102), which were subsequently cyclized in acetic acid to give excellent yields of the 23-dihydroxypyrazines. 

The formula of ethyl oxamate similarly shows that firom one point of view it appears as an amide, firom the other as an ether... 

Interchanging functionalities of the reacting species in the aforementioned reaction, that is, reacting sugar amidrazones (694) with acid derivatives such as ethyl oxamate, has also been used to synthesize 1,2,4-triazole C-nucleosides such as 6% (91MI26) (Scheme 186). 

Convenient routes to methyl-2-oxalylimino- and 2-(phosphonoformimido)-3,3,3-trifluoropropanoates (165) have been elaborated, based on the reaction of methyl trifluoropyruvate (166) with ethyl oxamate or diethyl carbomoylphosphonate, respectively, followed by dehydration and then alkylation. ... 

The IR spectrum of Cu(stpy)2(0Ac)2(H20)2,where stpy = trans-4-styryl-pyridine, includes bands from unidentate acetato ligands. Raman and IR spectra of the copper complex CuL2, where HL = N-ethyl oxamate, EtH-NCOCOOH, are consistent with bidentate coordination, through C = 0 and a unidentate carboxylate. ... 

A soln. of aminoacetaldehyde ethylene acetal and ethyl oxamate in ethanol refluxed 6 hrs. N-oxamoylaminoacetaldehyde diethyl acetal (Y 91.5%) dissolved in glacial acetic acid, and refluxed 6 hrs. under Ng 2,3-dihydroxypyrazine... 

Ethyl malonate as nitrous acid scavenger 26, 361 Ethyl oxamate... 

Ethyl oxamate 114 gives p-bromo-deriv., 167. Hot aniline gives oxanilide. 

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