Scheme 1.

Synthetic route of P1-β-amino acid-based (A) and P2-β-amino acid-based (B) peptidomimetics. Reagents and conditions: a) HATU, HOAt, Hunig’s base, DMF; b) TFA in DCM (20%); c) Boc-Asp(OBn)OH, HATU, HOAt, Hünig’s base, DMF; d) Pd/C (10%), H₂, methanol; e) ^tBuNH₂, EDC, HOBt, Hünig’s base, DMF; f) R¹COOH, HATU, HOAt, Hünig’s base, DMF or R¹Cl, Et₃N, DCM; g) Et₃N, DCM, 0°C – RT; h) Boc-β-Glu(OBn)OH, HATU, HOAt, Hünig’s base, DMF; i) R²COOH, HATU, HOAt, Hünig’s base, DMF or R²Cl, Et₃N, DCM.