The traditional peptide drugs are unstable in vivo conditions due to hydrolysis. The β-peptide that composed of β-amino acids has improved pharmacokinetic parameters than α-peptide and is valuable in drug development. The conformation restricted β-amino acids can form the β-peptidomimetics in order to improve its biological activity and metabolic stability. The restricted β-peptidomimetics can form fixed secondary structure and fold with specific way, then it has an ideal three-dimensional structure and embed in specific enzymes or receptors eventually. This review describes the methods of conformational restriction and the changes of biological activity or physical and chemical parameters after conformational restriction for β-peptidomimetics. Two kinds of conformationally restricted β-peptidomimetics including the local conformational restriction and the overall cyclization of β-peptidomimetics are reviewed. This paper could provide guidance for the rational design of β-peptide drugs.

Contents
1 Introduction
2 Local conformational restriction of β-peptides
2.1 Monoalkylating β² or β³-amino acids
2.2 Dialkylating β^2,3-amino acids
2.3 C^α-fluorinated β-amino acids
2.4 N-substituted β-amino acids
2.5 Ring substituted β-amino acids
3 The overall cyclization of β-peptides
3.1 Cyclization between the head and tail
3.2 Cyclization between the side chains
4 Research methods of the conformational restriction
4.1 Circular dichroism spectroscopy
4.2 Infrared spectroscopy
4.3 X-ray diffraction analysis
4.4 Nuclear magnetic resonance
4.5 Theoretical calculations
5 Conclusion