Synthesis of γ-glutamyl derivatives of sulfur-containing amino acids in a multigram scale via a two-step, one-pot procedure

γ-Glutamyl derivatives of sulfur amino acids have been prepared in multigram scale starting from readily available starting materials. The synthesis comprises two one-pot operations, both consisting of two reactions. In the first operation, N-phtaloyl-l-glutamic acid anhydride is obtained from l-glutamic acid and phtalic anhydride. In the second one, N-phtaloyl-l-glutamic acid anhydride is used to acylate amino acids and the N-phtaloyl protecting group is removed. The described approach offers a viable entry to γ-glutamyl derivatives of sulfur-containing amino acids with flavor-enhancer and nutraceutical properties.