Synthesis of oligopeptides consisting of L ‐leucyl‐ L ‐leucyl‐ L ‐ananyl and L ‐methionyl‐ L ‐methionyl‐ L ‐leucyl repeating units with an improved preparation of Nps‐amino acids

Two series of peptides with hydrophobic side chains, Nps‐(L‐Leu‐L‐Leu‐L‐Ala)n‐OEt and Nps‐(L‐Met‐L‐Met‐LLeu)n‐OEt (n = 1–6), were synthesized by the fragment condensation method using dicyclohexylcarbodiimide in the presence of N‐hydroxysuccinimide. The tripeptide fragments were prepared stepwise by dicyclohexylcarbodiimide‐mediated reaction of Nps‐amino acids, which were synthesized by an improved rapid procedure.