The invention relates to the field of
drug synthesis, and discloses a method for preparing semeglutide through fragment condensation, which comprises the following steps: taking 1-4 amino acids of a semeglutide
amino acid sequence as a fragment I, 1-16 amino acids of the
amino acid sequence as a fragment II, 17-29 amino acids of the
amino acid sequence as a fragment III, and 30-31 amino acids of the amino acid sequence as a fragment IV; preparing the first fragment, the second fragment, the third fragment and the fourth fragment into a semeglutide product by adopting a
solid-liquid
combination method; the fragment I of the method can effectively inhibit
racemization impurities of His; the C-terminal amino acids of the second fragment, the third fragment and the fourth fragment in the method are all Gly, and
racemization impurities cannot be generated when the three fragments are condensed. In addition, the fragment synthesized by the fragment II, the fragment III and the fragment IV is high in purity and good in
solubility, the
condensation reaction efficiency of the polypeptide fragment is high, the fragment
utilization rate is high, the cost is low, the unutilized fragment can be extracted and separated, and the post-treatment is simple.