Synthesis of a cyclic pseudopeptide containing a flexible β-Alaψ[CH2NH]unit

The target cyclic pseudopeptide, cyclo(Tyr-Gly-β-Alaψ[CH2NH]Ala-Phe-Leu), was efficiently synthesized using a methodology combining solid phase synthesis of the linear pseudopeptide and solution phase cyclization of the linear pseudopeptide.