Finally, cyclo(-Ab7-Aib-Phe(2-Me)-D-Pro-) is successfully prepared by using liquid phase peptide synthesis with Boc protection.

• Boc-Ab7-Aib-Phe(2-Me)-D-Pro-OBzl脱除两端保护得到线性肽链经过环化得到目标产物cyclo(-Ab7-Aib-Phe(2-Me)-D-Pro-)，收率0.；8%25。