Sodium thiosulfate efficiently removed copper from amino acid-copper complexes. This new method was suitable for the synthesis of N^δ-benzyloxycarbonyl-L-ornithine, N^δ-tert-butyloxycarbonyl-L-ornithine, N^δ-fluorenylmethyloxycarbonyl-L-ornithine, N^δ-acetyl-L-ornithine, N^δ-phthalyl-L-ornithine, N^δ-benzyloxycarbonyl-L-lysine, N^δ-tert-butyloxycarbonyl-L-lysine, N^δ-fluorenylmethyloxycarbonyl-L-lysine, N^δ-acetyl-L-lysine, N^δ-phthalyl-L-lysine, γ-benzyl-glutamate, β-benzyl-aspartate and their molecular structures were confirmed by elemental analysis and ¹H NMR. The effects of reaction remperature, time, materials propor-tion and solvent on copper-removing reaction were studied. It was shown that when N^δ-protective ornithine copper complexes and sodium thiosulfate were reacted with the molar ratio of 1∶1 or 1∶2 at 60 ℃ for 1.5～2.0 h, the product yield and purity were high. The method is rapid, convenient in operation and environment friendly.

Key words: sodium thiosulfate, copper removal, copper-amino acid complex, protected amino acid