The Reaction of Glyoxylic Acid with Ammonia Revisited

Article abstract of DOI:10.1021/jo00040a035

Upon addition of ammonia or an alkylamine to glyoxylic acid an ammonium derivative of glyoxylic acid precipitates quantitatively.With the use of solid-state 13C and 15N NMR spectroscopy, it is shown that adducts of glyoxylic acid and ammonia or the alkylamine are obtained.These compounds are not stable in aqueous solution.The compositions of the aqueous solutions have been investigated by 1H, 13C, 15N, and 17O NMR.Under basic conditions hexahydro-s-triazine-2,4,6-tricarboxylate is the predominant species in a solution of the adduct of ammonia and glyoxylic acid, whereas upon acidification (pH < 6) glyoxylate is the only organic species.In a basic solution of the adduct of ethylamine and glyoxylic acid N-ethyliminoacetate is the only species.The N-methyl adduct shows an intermediate behavior: both the hexahydrotriazine and the imine are observed.Under acidic conditions deamination to glyoxylate always occurs.Intermediates in the reaction of glyoxylic acid and ammonia could be detected with 1H NMR, when the reaction was performed with an excess of ammonia.The mechanism of these reactions is discussed.