A new synthesis of α-amino acids—III Amidoalkylation of active methylene compounds with glyoxylic acid derivatives

Abstract 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 acid derivatives ( 4, 5 ) were further converted to the corresponding butenolides ( 6, 7 ) and to pyrazolylglycine ( 12 ).