Solid-State Conformation of a Hybrid Tripeptide between β-Amino Acid; 8-Aminocyclooct-4-enecarboxylic Acid and 2-Aminoisobutyric Acid

Abstract

An eight-membered cyclic β-amino acid, 8-aminocyclooct-4-enecarboxylic acid, was designed as a conformationally restricted non-proteinogenic amino acid. A hybrid tripeptide containing this eight-membered cyclic β-amino acid and 2-aminoisobutyric acids was synthesized by conventional solution methods. The conformation of the tripeptide was studied using X-ray analysis and was shown to form an eleven-membered hydrogen-bonded turn (3₁₁-helical structure) in the solid state.