New Imidazoles Formed in Nonenzymatic Browning Reactions

ABSTRACT 1,3‐Bis(carboxymethyl)imidazole was identified in a model reaction mixture derived from glycine, glyoxal, and formaldehyde. The same compound was also found in the reaction of glycine with glyoxal. The structure of this compound was elucidated from the measured molecular, mass and 1 H‐NMR and 13 C‐NMR spectral data and confirmed by X‐ray crystallographic measurements. Similarly, a 2‐methyl‐, 4‐methyl‐, and 2,4‐dimethyl‐1,3‐bis(carboxymethyl)‐imidazole were formed in reactions of glycine with glyoxal or methylglyoxal and formaldehyde or acetaldehyde. These 1,3‐symmetrically substituted imidazoles represent quite a new group of N‐containing heterocyclic compounds originating in model systems containing amino acids and α‐dicarbonyl compounds and probably also in natural systems.