Incorporation of the α-mercapto acid unit into peptides

Incorporation of α-mercapto acid units into the backbone of potential drug candidates improves the metal ion complexing properties. So far, only the methodology for the N-terminal incorporation of mercapto acid units into peptides has been described. Now, we report on a modified strategy for the incorporation of the α-mercapto acid unit into any position of a peptide backbone starting from hexafluoroacetone-protected thiomalic acid. Concomitantly with the incorporation of the α-mercapto unit the direction of the peptide chain is inverted.