Preparation method of oligopeptide Fmoc-L-Ala-L-Ala-OH

The invention discloses a preparation method of short peptide Fmoc-L-Ala-L-Ala-OH, which adopts a liquid phase synthesis method and comprises the following steps: reacting N-fluorenylmethoxycarbonyl-L-alanine, namely Fmoc-L-Ala-OH, with an activator HOR in an organic solvent in the presence of a condensing agent to prepare active ester Fmoc-L-Ala-OR, coupling the active ester Fmoc-L-Ala-OR with trimethylsilyl, namely L-alanine, namely H-L-Ala-OH which is temporarily protected by TMS (Trimethylsilyl), and carrying out a reaction to obtain the short peptide Fmoc-L-Ala-L-Ala-OH. And the oligopeptide Fmoc-L-Ala-L-Ala-OH is prepared by the steps of carrying out According to the preparation method,-TMS temporary protection is creatively used for oligopeptide synthesis, the target oligopeptide with the purity higher than 90% can be simply and efficiently prepared without column chromatography purification, and the preparation method has the advantages of being short in step, easy to operate, high in product purity,