The synthesis of N-acyl derivatives of γ - keto - α - amino acids (3, 4, 5) by the amidoalkylation of 1,3-dicarbonyl compounds with glyoxylic acid-amide adducts (1, 2) is described. The γ - keto - α - amino acidderivatives (4, 5) were further converted to the corresponding butenolides (6, 7) and to pyrazolylglycine (12).