Method for preparing glp-1 agonist polypeptide compound

A method for preparing a GLP-1 agonist polypeptide compound, the GLP-1 agonist polypeptide compound having an amino acid sequence:

• HXaa1EGTFTSDVSSYLEXaa2QAAXaa3EFIAWLVRGRG (SEQ ID NO:
• 1);
• wherein:
• Xaa1 is:
• Xaa2 is G;
• R1 is a straight-chain or branched-chain alkyl containing 2-6 carbon atoms;
• R2 is H or CH3;
• X is O, S or N—CH3;
• R1 is optionally substituted by 1-5 halogen atoms in the case of 2 carbon atoms and 1-6 halogen atoms in the case of 3-6 carbon atoms;
• R2 is optionally substituted by 1-3 halogen atoms when R2 is CH3;
• Xaa3 is:
• the method comprising:
• 1. preparing a Fmoc-Gly31-Wang resin;
• 2. adding the Fmoc-Gly31-Wang resin to a solid-phase reactor;
• 3. coupling Fmoc-Arg30 (Pbf)-OH, Fmoc-Gly29-OH, Fmoc-Arg28 (Pbf)-OH, Fmoc-Val27-OH, Fmoc-Leu26-OH, Fmoc-Trp25 (Boc)-OH, Fmoc-Ala24-OH, Fmoc-Ile23-OH, Fmoc-Phe22-OH, Fmoc-Glu21 (OtBu)-OH, Fmoc-Lys20 (Xaa3)-OH, Fmoc-Ala19-OH, Fmoc-Ala18-OH, Fmoc-Gln17 (Trt)-OH, Fmoc-Gly16-OH, Fmoc-Glu15 (OtBu)-OH, Fmoc-Leu14-OH, Fmoc-Tyr13 (tBu)-OH, Fmoc-Ser12 (tBu)-OH, Fmoc-Ser11 (tBu)-OH, Fmoc-Val10-OH, Fmoc-Asp9 (OtBu)-OH, Fmoc-Ser8 (tBu)-OH, Fmoc-Thr7 (tBu)-OH, Fmoc-Phe6-OH, Fmoc-Thr5 (tBu)-OH, Boc-His1 (Trt)-Xaa1-Glu3 (OtBu)-Gly4-OH to the Fmoc-Gly31-Wang one by one by using a solid-phase synthesis method;
• wherein:
• the fragment Fmoc-Lys20 (Xaa3)-OH has a structural formula as follows:
• n is a natural number ranging from 12 to 20, and m is a natural number ranging from 0 to 3;
• and
• a condensing agent used is one or more of DIC/HOBt, DIC/Oxymapure, HBTU/HOBt/DIEA, PyBop/HOBt/DIEA;
• a reaction solvent used is one or a combination of more of DCM, DMF, NMP and DMSO;
• and an Fmoc removal agent used is a v/v 25% piperidine/DMF solution;
• 4. cleaving a resulting peptide resin to obtain a crude peptide, wherein a cleavage reagent is a composite reagent comprising trifluoroacetic acid (TFA) and a scavenger mixture in a volume ratio of 95:5, and the scavenger mixture comprises any combination of scavengers selected from the group consisting of thioanisole, triisopropylsilane (TIS), 1,2-ethanedithiol (EDT), phenol, and water.