Method for synthesizing liraglutide

The invention discloses a method for synthesizing liraglutide. The method comprises the steps of performing solid phase synthesis to obtain the first to fourth sites of amino acid of a liraglutide sequence as a first fragment; performing solid phase synthesis to obtain the fifth to thirty-first sites of amino acid of the liraglutide sequence, removing side chain protection groups of the twentiethsite of Lys and coupling Pal-gamma-Glu to be used as a second fragment; and coupling the first fragment and the second fragment, synthesizing full protection liraglutide, cracking and settling to obtain the liraglutide. The method for synthesizing the liraglutide improves the purity of crude peptide, greatly reduces material costs and purification costs, and is suitable for industrial large-scaleproduction. 本发明公开了种利拉鲁肽的合成方法，其步骤是：固相合成利拉鲁肽序列的第1-4位氨基酸作为第片段；固相合成利拉鲁肽序列的第5-31位氨基酸，脱除20位Lys的侧链保护基团并偶联Pal-γ-Glu，作为第二片段；第片段与第二片段偶联，合成全保护利拉鲁肽，经裂解沉淀，得到利拉鲁肽。本发明合成方法提高了粗肽纯度，极大降低了物料成本和纯化成本，利于进行工业化放大生产。