Synthesis of ‘difficult’ peptide sequences: application of a depsipeptide technique to the Jung–Redemann 10- and 26-mers and the amyloid peptide Aβ(1–42)

Recently a 26-mer peptide 1 incorporating Ser and Thr was described as a ‘difficult’ sequence that could not be synthesized by standard methods. If the first Ser residue was used to incorporate a depsipeptide unit, the resulting hybrid was readily assembled. The 26-mer ester was then converted to the native peptide by an O→N acyl shift. The technique may be general for other systems containing appropriate Ser and Thr units and was demonstrated here for the case of the amyloid peptide Aβ(1–42).