Polypeptides with modified structures and uses thereof

Abstract

The present invention provides a series of polypeptides with modified structures that act on three targets, GLP-1, GIP, and GCG, and are expected to be developed as pharmaceuticals for preventing or treating metabolic diseases, the polypeptide sequences of which are shown in Formula Z-3. X5X0X6GT FTSDY SIX1X7X8KX9X 10 X 11 X0X4FX 12 X 13 X 14 LLX 15 GG PSSGA PPPS0 Z-3

Description

[Technical Field]

[0001] The present invention relates to a series of polypeptides with modified structures and uses thereof, in particular to a series of polypeptides with stapled structures, pharmaceutical compositions comprising the series of polypeptides, and their use in the treatment of metabolic disorders. [Background technology]

[0002] Glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) are incretins, and glucagon (GCG) is secreted from pancreatic islet α cells. These substances directly or indirectly affect glucose and / or lipid metabolism in humans. Therefore, compounds acting on GLP-1, GIP, and GCG are promising candidates for development as drugs to treat metabolic diseases. For example, compounds (polypeptides) acting on GLP-1, such as exenatide, liraglutide, and semaglutide, are currently available as drugs for the treatment of type 2 diabetes mellitus type 2 (T2DM) and / or obesity.

[0003] However, compounds that act on a single GLP-1, GIP, or GCG target typically have shortcomings in terms of therapeutic area, therapeutic efficacy, and metabolic behavior, which ultimately affect the compound's drug discovery potential and clinical application after launch. Therefore, efforts are being made to develop compounds that act on multiple targets, aiming to simultaneously intervene in multiple mechanisms and achieve better clinical efficacy. Tirzepatide, a GLP-1 / GIP dual agonist developed by Eli Lilly and Company, demonstrated superior efficacy compared to semaglutide in a head-to-head clinical trial and has currently been approved for marketing. LY3437943, a GLP-1 / GIP / GCG triple agonist also developed by Eli Lilly and Company, has also demonstrated favorable clinical efficacy in clinical trials and has good prospects for development.

[0004] GLP-1R / GIPR / GCGR multiple agonists can activate the molecular mechanisms of blood glucose-regulating receptors, thereby affecting food intake and satiety through different mechanisms and playing a role in maintaining weight homeostasis. Meanwhile, research has shown that GLP-1 receptor agonists can enhance the action of incretins by activating GLP-1 receptors, exerting excellent blood glucose lowering and weight loss effects, and can also treat NASH (non-alcoholic steatohepatitis) through multi-pathway synergistic effects. Therefore, compounds that act on this target or multiple targets may be developed as drugs for the prevention and / or treatment of a range of specific diseases associated with abnormal glucose metabolism and / or abnormal lipid metabolism. Summary of the Invention [Problem to be solved by the invention]

[0005] In order to overcome the drawbacks of the prior art, the present invention provides a series of polypeptides and pharmaceutically acceptable salts thereof having modified structures, which show favorable effects on GLP-1 receptor (GLP-1R), GIP receptor (GIPR) and GCG receptor (GCGR) in in vitro tests and have good prospects for drug discovery. [Means for solving the problem]

[0006] The present invention relates to a polypeptide having a polypeptide sequence shown in formula Z: X5X0X6GT X a TSDY SX b X1X7X8KX9X 10 X 11 X0X4FX 12 X 13 X 14 X c X d X 15 GG PSSGA PPPS0 formula Z where: X0 is TIFF2026503073000002.tif17170 or Aib or alanine (Ala, A), and the structure of Aib above is TIFF2026503073000003.tif17170X1 is independently selected from α-methyl-substituted leucine (α-MeLeu, α-MeL), tyrosine (Tyr, Y), or Aib, and the structure of α-MeL above is TIFF2026503073000004.tif17170X4 is selected from α-methyl substituted lysine (α-MeLys, α-MeK), D-lysine (dK), L-ornithine (L-Ornithine, L-Orn), alanine (Ala, A), lysine (Lys, K), glutamic acid (Glu, E), or leucine (Leu, L), and the structure of the above α-methyl substituted lysine is TIFF2026503073000005.tif23170The structure of D-lysine (dK) is The structure of L-ornithine (L-Orn) is TIFF2026503073000007.tif23170X5 is selected from tyrosine (Tyr, Y) or histidine (His, H), X6 is selected from glutamine (Gln, Q) or histidine (His, H); X7 is selected from leucine (Leu, L) or lysine (Lys, K); X8 is selected from aspartic acid (Asp, D) or glutamic acid (Glu, E); X9 is selected from lysine (Lys, K), glutamine (Gln, Q) or glutamic acid (Glu, E); X 10 is selected from alanine (Ala, A) or tyrosine (Tyr, Y), X 11 is selected from lysine (Lys, K), glutamine (Gln, Q) or alanine (Ala, A), X 12 is selected from valine (Val, V) or isoleucine (Ile, I), X 13 is selected from lysine (Lys, K), glutamine (Gln, Q) or glutamic acid (Glu, E), X 14is selected from lysine (Lys, K), tryptophan (Trp, W), tyrosine (Tyr, Y), glutamic acid (Glu, E) or phenylalanine (Phe, F); X 15 is selected from lysine (Lys, K) or glutamic acid (Glu, E), X a is selected from phenylalanine (Phe, F) or α-methyl-substituted phenylalanine (α-MePhe, α-MeF), and the α-methyl-substituted phenylalanine structure is TIFF2026503073000008.tif24170X b is selected from lysine (Lys, K) or isoleucine (Ile, I), X c is selected from leucine (Leu, L) or phenylalanine (Phe, F); X d is selected from leucine (Leu, L) or isoleucine (Ile, I), S0 is TIFF2026503073000009.tif23170 (i.e., the C-terminal amino acid is optionally amidated to a C-terminal primary amide); And the compound (polypeptide) is 1) amino acid side chains at positions i and i+j in a sequence can be linked by modifications to form a modified structure (staplebody) similar to a "staple" structure (peptide staple), where i is independently selected from 12, 14, 16, 17, 19, 21, 24, or 25, and j is independently selected from 2, 3, 4, 5, or 7; 2) The above modifications are carried out by modifying the amino or carboxyl groups on the side chains of the two amino acid unit structures. TIFF2026503073000010.tif15170 and modifications linked by condensation; Including, X2 is TIFF2026503073000011.tif42170 where "*" indicates the position linked to X3, and both ends are positions linked to the corresponding amino or carboxyl groups of the modified amino acid. X3 is selected from the group shown in TIFF2026503073000012.tif161170; R1 and R2 are independently selected from the groups shown in TIFF2026503073000013.tif17170; m is selected from 1, 2, or 3; p is selected from 1 or 2; The present invention provides a polypeptide having a modified structure, wherein n is selected from 8, 9, and 10, and a pharmaceutically acceptable salt thereof.

[0007] In some aspects of the present invention, a polypeptide or a pharmaceutically acceptable salt thereof having a modified structure has a polypeptide sequence represented by formula Z-1: X5X0X6GT FTSDY SX b X1X7X8KX9X 10 X 11 X0X4FX 12 X 13 X 14 X c X d X 15 GG PSSGA PPPS0 Formula Z-1 The above compound (polypeptide) is 1) amino acid side chains at positions i and i+j in the sequence can be linked by modifications to form a modified structure (staple body) similar to a "staple" (peptide staple) structure, where i is independently selected from 12, 14, 16, 17, 19, 21, 24, or 25, and j is independently selected from 2, 3, 4, 5, or 7; 2) The above modifications are carried out by modifying the amino or carboxyl groups on the side chains of the two amino acid unit structures. TIFF2026503073000014.tif14170 and modifications linked by condensation, with other variables as defined herein.

[0008] In some aspects of the present invention, a polypeptide or a pharmaceutically acceptable salt thereof having a modified structure has a polypeptide sequence represented by formula Z-2: X5X0X6GT FTSDY SIX1X7X8KX9X 10 X 11 X0X4FX 12 X 13 X 14 LLX 15 GG PSSGA PPPS0 Formula Z-2 The above compound (polypeptide) is 1) amino acid side chains at positions i and i+j in the sequence can be linked by modifications to form a modified structure (staple body) similar to a "staple" structure, where i is independently selected from 12, 14, 16, 17, 19, 21, 24, 25, and j is independently selected from 2, 3, 4, 5, 7; 2) The above modifications are carried out by modifying the amino or carboxyl groups on the side chains of the two amino acid unit structures. TIFF2026503073000015.tif14170 and modifications linked by condensation, with other variables as defined herein.

[0009] In some aspects of the present invention, the polypeptide or pharmaceutically acceptable salt thereof having a modified structure has a polypeptide sequence represented by formula Z-3: X5X0X6GT FTSDY SIX1X7X8KX9X 10 X 11 X0X4FX 12 X 13 X 14 LLX 15 GG PSSGA PPPS0 Formula Z-3 The polypeptide compound is 1) amino acid side chains at positions i and i+j in the sequence can be linked by modifications to form a modified structure (staple body) similar to a "staple" structure, where i is independently selected from 14, 17, 19, 21, 24, or 25, and j is independently selected from 3, 4, 5, or 7; 2) The above modifications are carried out by modifying the amino or carboxyl groups on the side chains of the two amino acid unit structures. TIFF2026503073000016.tif13170 and modifications linked by condensation, Including, X2 is TIFF2026503073000017.tif41170 where "*" indicates the position linked to X3, and both ends are positions linked to the corresponding amino or carboxyl groups of the modified amino acid. X3 is selected from the group shown in TIFF2026503073000018.tif173170; R1 and R2 are independently selected from the group represented by TIFF2026503073000019.tif20170; m is selected from 1, 2, or 3; p is selected from 1 or 2; n is selected from 8, 9, or 10, and the other variables are as defined herein.

[0010] In some aspects of the present invention, a polypeptide or a pharmaceutically acceptable salt thereof having a modified structure has a polypeptide sequence represented by formula Z-4: YX0QGT FTSDY SX b X1LD KKAQX0X4FX 12 X 13 X 14 X c X d X 15 GG PSSGA PPPS0 Formula Z-4 S0 is TIFF2026503073000020.tif23170 (i.e., the C-terminal amino acid is optionally amidated to a C-terminal primary amide); And the polypeptide compound is 1) amino acid side chains at positions i and i+j in the sequence can be linked by modifications to form a modified structure (staple body) similar to a "staple" structure, where i is independently selected from 12, 17, 21, or 25, and j is independently selected from 3, 4, or 7; 2) The above modifications are carried out by modifying the amino or carboxyl groups on the side chains of the two amino acid unit structures. TIFF2026503073000021.tif13170 and modifications linked by condensation, Including, X2 is TIFF2026503073000022.tif11170, wherein "*" indicates the position linked to X3, and both ends are positions linked to the corresponding amino group or carboxyl group of the modified amino acid; X3 is selected from the group shown in TIFF2026503073000023.tif44170; m is selected from 1, 2, or 3; p is selected from 1 or 2; n is selected from 8, 9, or 10, and the other variables are as defined herein.

[0011] In some aspects of the present invention, a polypeptide or a pharmaceutically acceptable salt thereof having a modified structure has a polypeptide sequence represented by formula Z-5: YX0QGT X a TSDY SIX1KD KKAQX0X4FIX 13 Y LLX 15 GG PSSGA PPPS0 Formula Z-5 The polypeptide compound is 1) amino acid side chains at positions i and i+j in the sequence can be linked by modifications to form modified structures similar to "staple" structures, where i is independently selected from 14 and j is independently selected from 3; 2) The above modifications are carried out by modifying the amino or carboxyl groups on the side chains of the two amino acid unit structures. TIFF2026503073000024.tif14170 and modifications linked by condensation, Including, X2 is TIFF2026503073000025.tif11170, wherein "*" indicates the position linked to X3, and both ends are positions linked to the corresponding amino group or carboxyl group of the modified amino acid; X3 is selected from the group shown in TIFF2026503073000026.tif66170; m is selected from 1, 2, or 3; p is selected from 1 or 2; n is selected from 8, 9, or 10, and the other variables are as defined herein.

[0012] In some aspects of the present invention, the polypeptides or pharmaceutically acceptable salts thereof having modified structures have polypeptide sequences represented by formulas Z-6, Z-7, Z-8, Z-9, Z-10, Z-11, Z-12, and Z-13, respectively: X5X0X6GT FTSDY SIX1LX8KKX 10 X 11 X0X4FX 12 X 13 X 14 LLX 15 GG PSSGA PPPS0 Formula Z-6 YX0QGT FTSDY SIX1LD KKAX 11 X0X4FIX 13 X 14 LLX 15 GG PSSGA PPPS0 Formula Z-7 YX0QGT FTSDY SIX1X7D KKAQX0X4FIX 13 Y LLX 15 GG PSSGA PPPS0 Formula Z-8 YX0QGT FTSDY SXbX1LD KKAQX0X4FX 12 EX 14 X c XdX 15 GG PSSGA PPPS0 Formula Z-9 YX0QGT FTSDY SX b X1LD KKAQX0KFX 12 EX 14 LX d X 15 GG PSSGA PPPS0 Formula Z-10 YX0QGT FTSDY SX b X1KD KKAQX0X4FIEY LLX 15 GG PSSGA PPPS0 Formula Z-11 YX0QGT FTSDY SIX1KD KKAQX0X4FIEY LLEGG PSSGA PPPS0 Formula Z-12 YX0QGT X a TSDY SIX1KD KKAQX0X4FIEY LLX 15 GG PSSGA PPPS0 Formula Z-13 The above compound (polypeptide) is 1) amino acid side chains at positions i and i+j in the sequence can be linked by modifications to form a modified structure (staple body) similar to a "staple" structure, where i is independently selected from 12, 14, 16, 17, 19, 21, 24, or 25, and j is independently selected from 2, 3, 4, 5, or 7; 2) The above modifications are carried out by modifying the amino or carboxyl groups on the side chains of the two amino acid unit structures. TIFF2026503073000027.tif14170 and modifications linked by condensation, Including, X2 is TIFF2026503073000028.tif40170, wherein "*" indicates the position linked to X3, and both ends are positions linked to the corresponding amino group or carboxyl group of the modified amino acid; X3 is selected from the group shown in TIFF2026503073000029.tif123170; R1 and R2 are independently selected from the group represented by TIFF2026503073000030.tif16170; m is selected from 1, 2, or 3; p is selected from 1 or 2; n is selected from 8, 9, or 10, and the other variables are as defined herein.

[0013] In some aspects of the present invention, S0 in the above polypeptide sequence is TIFF2026503073000031.tif23170, i.e., the C-terminal amino acid is amidated to a primary amide, and the other variables are as defined herein.

[0014] In some aspects of the invention, amino acid X0 at position 2 of the polypeptide sequence is Aib, and the other variables are as defined herein.

[0015] In some aspects of the invention, amino acid X0 at position 20 of the polypeptide sequence is Aib, and the other variables are as defined herein.

[0016] In some aspects of the invention, amino acids X0 at positions 2 and 20 of the polypeptide sequence are both Aib, and the other variables are as defined herein.

[0017] In some aspects of the invention, i is 12, j is 4, and i+j is 16, and the other variables are as defined herein.

[0018] In some aspects of the invention, i is 14, j is 3, and i+j is 17, and the other variables are as defined herein.

[0019] In some aspects of the invention, i is 16, j is 3, and i+j is 19, and the other variables are as defined herein.

[0020] In some aspects of the invention, i is 17, j is 4, and i+j is 21, and the other variables are as defined herein.

[0021] In some aspects of the invention, i is 17, j is 7, and i+j is 24, and the other variables are as defined herein.

[0022] In some aspects of the invention, i is 19, j is 5, and i+j is 24, and the other variables are as defined herein.

[0023] In some aspects of the invention, i is 21, j is 7, and i+j is 28, and the other variables are as defined herein.

[0024] In some aspects of the invention, i is 24, j is 4, and i+j is 28, and the other variables are as defined herein.

[0025] In some aspects of the invention, i is 25, j is 3, and i+j is 28, and the other variables are as defined herein.

[0026] In some aspects of the invention, amino acid X5 at position 1 of the polypeptide sequence is Y, and the other variables are as defined herein.

[0027] In some aspects of the invention, amino acid X5 at position 1 of the polypeptide sequence is H, and the other variables are as defined herein.

[0028] In some aspects of the invention, amino acid X6 at position 3 of the polypeptide sequence is Q, and the other variables are as defined herein.

[0029] In some aspects of the invention, amino acid X6 at position 3 of the polypeptide sequence is H, and the other variables are as defined herein.

[0030] In some aspects of the invention, amino acid X at position 6 of the polypeptide sequence a is F, and other variables are as defined herein.

[0031] In some aspects of the invention, amino acid X at position 6 of the polypeptide sequence a is α-MeF, and other variables are as defined herein.

[0032] In some aspects of the invention, amino acid X at position 12 of the polypeptide sequence b is I, and other variables are as defined herein.

[0033] In some aspects of the invention, amino acid X at position 12 of the polypeptide sequence b is K, and other variables are as defined herein.

[0034] In some aspects of the invention, amino acid X1 at position 13 of the polypeptide sequence is α-MeL, and the other variables are as defined herein.

[0035] In some aspects of the invention, amino acid X1 at position 13 of the polypeptide sequence is Y, and the other variables are as defined herein.

[0036] In some aspects of the invention, amino acid X1 at position 13 of the polypeptide sequence is Aib, and the other variables are as defined herein.

[0037] In some aspects of the invention, amino acid X7 at position 14 of the polypeptide sequence is L, and the other variables are as defined herein.

[0038] In some aspects of the invention, amino acid X7 at position 14 of the polypeptide sequence is K, and the other variables are as defined herein.

[0039] In some aspects of the invention, amino acid X8 at position 15 of the polypeptide sequence is D, and the other variables are as defined herein.

[0040] In some aspects of the invention, amino acid X8 at position 15 of the polypeptide sequence is E, and the other variables are as defined herein.

[0041] In some aspects of the invention, amino acid X9 at position 17 of the polypeptide sequence is K, and the other variables are as defined herein.

[0042] In some aspects of the invention, amino acid X9 at position 17 of the polypeptide sequence is Q, and the other variables are as defined herein.

[0043] In some aspects of the invention, amino acid X9 at position 17 of the polypeptide sequence is E, and the other variables are as defined herein.

[0044] In some aspects of the invention, amino acid X at position 18 of the polypeptide sequence 10 is A, and the other variables are as defined herein.

[0045] In some aspects of the invention, amino acid X at position 18 of the polypeptide sequence 10is Y, and other variables are as defined herein.

[0046] In some aspects of the invention, amino acid X at position 19 of the polypeptide sequence 11 is Q, and the other variables are as defined herein.

[0047] In some aspects of the invention, amino acid X at position 19 of the polypeptide sequence 11 is A, and the other variables are as defined herein.

[0048] In some aspects of the invention, amino acid X at position 19 of the polypeptide sequence 11 is K, and other variables are as defined herein.

[0049] In some aspects of the invention, amino acid X4 at position 21 of the polypeptide sequence is K, and the other variables are as defined herein.

[0050] In some aspects of the invention, amino acid X4 at position 21 of the polypeptide sequence is A, and the other variables are as defined herein.

[0051] In some aspects of the invention, amino acid X4 at position 21 of the polypeptide sequence is E, and the other variables are as defined herein.

[0052] In some aspects of the invention, amino acid X4 at position 21 of the polypeptide sequence is α-MeK, and the other variables are as defined herein.

[0053] In some aspects of the invention, amino acid X4 at position 21 of the polypeptide sequence is dK, and the other variables are as defined herein.

[0054] In some aspects of the invention, amino acid X4 at position 21 of the polypeptide sequence is L-Orn, and the other variables are as defined herein.

[0055] In some aspects of the invention, amino acid X4 at position 21 of the polypeptide sequence is L, and the other variables are as defined herein.

[0056] In some aspects of the invention, amino acid X at position 23 of the polypeptide sequence 12 is I, and other variables are as defined herein.

[0057] In some aspects of the invention, amino acid X at position 23 of the polypeptide sequence 12 is V, and other variables are as defined herein.

[0058] In some aspects of the invention, amino acid X at position 24 of the polypeptide sequence 13 is E, and the other variables are as defined herein.

[0059] In some aspects of the invention, amino acid X at position 24 of the polypeptide sequence 13 is K, and other variables are as defined herein.

[0060] In some aspects of the invention, amino acid X at position 24 of the polypeptide sequence 13 is Q, and the other variables are as defined herein.

[0061] In some aspects of the invention, amino acid X at position 25 of the polypeptide sequence 14 is Y, and other variables are as defined herein.

[0062] In some aspects of the invention, amino acid X at position 25 of the polypeptide sequence 14 is W, and other variables are as defined herein.

[0063] In some aspects of the invention, amino acid X at position 25 of the polypeptide sequence 14 is K, and other variables are as defined herein.

[0064] In some aspects of the invention, amino acid X at position 25 of the polypeptide sequence 14 is E, and the other variables are as defined herein.

[0065] In some aspects of the invention, amino acid X at position 25 of the polypeptide sequence 14 is F, and other variables are as defined herein.

[0066] In some aspects of the invention, amino acid X at position 26 of the polypeptide sequence c is L, and other variables are as defined herein.

[0067] In some aspects of the invention, amino acid X at position 26 of the polypeptide sequence c is F, and other variables are as defined herein.

[0068] In some aspects of the invention, amino acid X at position 27 of the polypeptide sequence d is L, and other variables are as defined herein.

[0069] In some aspects of the invention, amino acid X at position 27 of the polypeptide sequence d is I, and other variables are as defined herein.

[0070] In some aspects of the invention, amino acid X at position 28 of the polypeptide sequence 15 is E, and the other variables are as defined herein.

[0071] In some aspects of the invention, amino acid X at position 28 of the polypeptide sequence 15is K, and other variables are as defined herein.

[0072] In some aspects of the present invention, X3 is TIFF2026503073000032.tif122170, and other variables are as defined herein.

[0073] In some aspects of the invention, in the above X3 structure, m is selected from 1 or 2, and the other variables are as defined herein.

[0074] In some aspects of the invention, in the above X3 structure, p is selected from 1, and the other variables are as defined herein.

[0075] In some aspects of the invention, in the above X3 structure, n is selected from 9, and the other variables are as defined herein.

[0076] In some aspects of the present invention, X3 is TIFF2026503073000033.tif159170, and other variables are as defined herein.

[0077] In some aspects of the present invention, X3 is TIFF2026503073000034.tif148170, and other variables are as defined herein.

[0078] In some aspects of the present invention, The structural unit shown in TIFF2026503073000035.tif14170 is TIFF2026503073000036.tif224170, and other variables are as defined herein.

[0079] In some aspects of the present invention, The structural unit shown in TIFF2026503073000037.tif14170 is TIFF2026503073000038.tif223170TIFF2026503073000039.tif57170, and other variables are as defined herein.

[0080] The present invention is directed to a compound represented by Formula I: Formula I:X5X0X6GT FTSDY SIX1X7X8KX9X 10 X 11 X0X4FX 12 X 13 X 14 LLX 15 GG PSSGA PPPS0 where: X0 is TIFF2026503073000040.tif16170Aib or alanine (Ala, A) were independently selected, and the structure of Aib above was TIFF2026503073000041.tif16170X1 is independently selected from α-methyl-substituted leucine (α-MeLeu, α-MeL) or tyrosine (Tyr, Y), and the structure of α-MeL above is TIFF2026503073000042.tif17170X4 has the following structure: TIFF2026503073000043.tif24170α-Methyl-substituted lysine (α-MeLys, α-MeK), structure TIFF2026503073000044.tif25170D-lysine (d-K), structure TIFF2026503073000045.tif23170 selected from L-ornithine (L-Orn), alanine (Ala, A), lysine (Lys, K) or glutamic acid (Glu, E); X5 is selected from tyrosine (Tyr, Y) or histidine (His, H); X6 is selected from glutamine (Gln, Q) or histidine (His, H); X7 is selected from leucine (Leu, L) or lysine (Lys, K); X8 is selected from aspartic acid (Asp, D) or glutamic acid (Glu, E); X9 is selected from lysine (Lys, K), glutamine (Gln, Q) or glutamic acid (Glu, E); X 10 is selected from alanine (Ala, A) or tyrosine (Tyr, Y), X 11 is selected from lysine (Lys, K), glutamine (Gln, Q) or alanine (Ala, A), X 12 is selected from valine (Val, V) or isoleucine (Ile, I), X 13 is selected from lysine (Lys, K), glutamine (Gln, Q) or glutamic acid (Glu, E), X 14 is selected from lysine (Lys, K), tryptophan (Trp, W), tyrosine (Tyr, Y), glutamic acid (Glu, E) or phenylalanine (Phe, F); X 15 is selected from lysine (Lys, K) or glutamic acid (Glu, E), S0 is TIFF2026503073000046.tif21170 (i.e., the C-terminal amino acid is optionally amidated to a C-terminal primary amide); And the above compound is 1) amino acid side chains at positions i and i+j in the sequence can be linked by modifications to form a modified structure (staple body) similar to a "staple" structure, where i is independently selected from 12, 14, 16, 17, 19, 21, 24, or 25, and j is independently selected from 2, 3, 4, 5, or 7; 2) The above modifications are carried out by modifying the amino or carboxyl groups on the side chains of the two amino acid unit structures. TIFF2026503073000047.tif14170 Modifications linked by condensation, Including, X2 is TIFF2026503073000048.tif40170, wherein "*" indicates the position linked to X3, and both ends are positions linked to the corresponding amino group or carboxyl group of the modified amino acid; X3 is selected from the group shown in TIFF2026503073000049.tif135170; R1 and R2 are independently selected from the group represented by TIFF2026503073000050.tif17170; The present invention provides a polypeptide having a modified structure, or a pharmaceutically acceptable salt thereof, wherein m is selected from 1, 2, or 3; p is selected from 1 or 2; and n is selected from 8, 9, or 10.

[0081] In some aspects of the present invention, X3 is TIFF2026503073000051.tif46170, and other variables are as defined herein.

[0082] In some aspects of the present invention, X3 is TIFF2026503073000052.tif45170, and other variables are as defined herein.

[0083] In some aspects of the present invention, X3 is TIFF2026503073000053.tif42170, and other variables are as defined herein.

[0084] In some aspects of the present invention, The structural unit shown in TIFF2026503073000054.tif14170 is TIFF2026503073000055.tif30170, and other variables are as defined herein.

[0085] In some aspects of the present invention, The structural unit shown in TIFF2026503073000056.tif14170 is TIFF2026503073000057.tif29170, and other variables are as defined herein.

[0086] The present invention is directed to a compound represented by Formula I: Formula I:X5X0X6GT FTSDY SIX1X7X8KX9X 10 X 11 X0X4FX 12 X 13 X 14 LLX 15 GG PSSGA PPPS0 where: X0 is TIFF2026503073000058.tif16170 or Aib or alanine (Ala, A), and the structure of Aib above is TIFF2026503073000059.tif16170X1 is independently selected from α-methyl-substituted leucine (α-MeLeu, α-MeL) or tyrosine (Tyr, Y), and the structure of α-MeL above is TIFF2026503073000060.tif17170X4 has the following structure: α-methyl-substituted lysine (α-MeLys, α-MeK), a group represented by TIFF2026503073000061.tif22170, the structure of which is D-lysine (d-K), a group represented by TIFF2026503073000062.tif23170, has the structure TIFF2026503073000063.tif22170, selected from L-ornithine (L-Orn), alanine (Ala, A), lysine (Lys, K) or glutamic acid (Glu, E); X5 is selected from tyrosine (Tyr, Y) or histidine (His, H); X6 is selected from glutamine (Gln, Q) or histidine (His, H); X7 is selected from leucine (Leu, L) or lysine (Lys, K); X8 is selected from aspartic acid (Asp, D) or glutamic acid (Glu, E); X9 is selected from lysine (Lys, K), glutamine (Gln, Q) or glutamic acid (Glu, E); X 10 is selected from alanine (Ala, A) or tyrosine (Tyr, Y), X 11 is selected from lysine (Lys, K), glutamine (Gln, Q) or alanine (Ala, A), X 12 is selected from valine (Val, V) or isoleucine (Ile, I), X 13 is selected from lysine (Lys, K), glutamine (Gln, Q) or glutamic acid (Glu, E), X 14 is selected from lysine (Lys, K), tryptophan (Trp, W), tyrosine (Tyr, Y), glutamic acid (Glu, E) or phenylalanine (Phe, F); X 15 is selected from lysine (Lys, K) or glutamic acid (Glu, E), S0 is TIFF2026503073000064.tif20170 (i.e., the C-terminal amino acid is optionally amidated to a C-terminal primary amide); And the above compound is 1) amino acid side chains at positions i and i+j in the sequence can be linked by modifications to form a modified structure (staple body) similar to a "staple" structure, where i is independently selected from 12, 14, 16, 17, 19, 21, 24, or 25, and j is independently selected from 2, 3, 4, 5, or 7; 2) The above modifications are carried out by modifying the amino or carboxyl groups on the side chains of the two amino acid unit structures. a modification linked by condensation with a group represented by TIFF2026503073000065.tif13170; Including, X2 is TIFF2026503073000066.tif20170, wherein "*" indicates the position linked to X3, and both ends are positions linked to the corresponding amino group or carboxyl group of the modified amino acid; X3 is selected from the group shown in TIFF2026503073000067.tif123170; The present invention provides a polypeptide having a modified structure, or a pharmaceutically acceptable salt thereof, wherein m is selected from 1, 2, or 3; p is selected from 1 or 2; and n is selected from 8, 9, or 10.

[0087] In some aspects of the present invention, polypeptides having the above-described modified structures can be linked by modifying amino acids with the same superscript number in a peptide chain sequence to form a modified group (staple body) similar to a "staple" structure, i.e., the amino acid side chains at positions i and i+j in the sequence can be modified to form a modified structure (staple body) similar to a "staple" structure, where i is independently selected from any integer between 10 and 28, such as 10, 12, 14, 16, 17, 19, 21, 24, or 25, and j is independently selected from any integer between 1 and 8, such as 1, 2, 3, 4, 5, 7, or 8. The number of "staple" structures described above is 1 to 2. In some embodiments, the first amino acid is located at position 25 of the peptide and the second amino acid is located at position 28 of the peptide. In some embodiments, the first amino acid is located at position 24 of the peptide and the second amino acid is located at position 28 of the peptide. In some embodiments, the first amino acid is located at position 17 of the peptide and the second amino acid is located at position 21 of the peptide. In some embodiments, the first amino acid is located at position 16 of the peptide and the second amino acid is located at position 19 of the peptide. In some embodiments, the first amino acid is located at position 17 of the peptide and the second amino acid is located at position 24 of the peptide. In some embodiments, the first amino acid is located at position 19 of the peptide and the second amino acid is located at position 24 of the peptide. In some embodiments, the first amino acid is located at position 21 of the peptide and the second amino acid is located at position 28 of the peptide. In some embodiments, the first amino acid is located at position 19 of the peptide and the second amino acid is located at position 24 of the peptide.

[0088] In some aspects of the present invention, polypeptides having the above modified structures may have at most 0, 1, 2, 3, or 4 amino acid insertions, deletions, modifications, or substitutions in the peptide chain sequence. For example, isoleucine (I) at position 12 may be substituted with lysine (K), leucine (L) at position 26 or 27 may be substituted with isoleucine (I) or phenylalanine (F), X1 at position 13 may be substituted with X0, and X0 at position 20 may be substituted with a natural amino acid such as alanine (A).

[0089] The present invention relates to a polypeptide having a sequence as shown below: TIFF2026503073000068.tif118170

[0090] The superscripts (left superscripts) in the sequences indicate modified amino acid unit structures, and amino acids with the same superscript number are linked by a modifying group to form an amino acid unit structure similar to a "staple" structure (staple body), for example, 1 K and 1 E represents a modified lysine and glutamic acid, which are linked by a modification group (KE modification). 1 K and 1 K represents a modified lysine, and both are linked by a modifying group (K-K modification). 1 K and 1 X4 represents a modified lysine and X4, both of which are linked by a modifying group (K-X4 modification), where X0, X1, X4 and S0 and the modification scheme are as defined in the present invention.

[0091] The present invention has the sequence shown below: YX0QGT FTSDY SIX1LD K 1 KAQX0 1 KFIEF LLEGG PSSGA PPPS0 YX0QGT FTSDY SIX1LD K 1 KAQX0 1 KFIEF LIEGG PSSGA PPPS0 YX0QGT FTSDY SIX1LD K 1 KAQX0 1 KFVEF LIEGG PSSGA PPPS0 YX0QGT FTSDY SIX1LD KKAQX0AFIE 1 KFI 1 KGG PSSGA PPPS0 YX0QGT FTSDY SIX1LD KKAQX0 1 KFIEF LL 1 KGG PSSGA PPPS0 YX0QGT FTSDY SIX0LD K 1 KAQX0 1 KFIEF LLEGG PSSGA PPPS0 YX0QGT FTSDY S 1 KX1LD 1 KKAQX0AFIEF LLEGG PSSGA PPPS0

[0092] Here, X0, X1 and S0 and the modification schemes are defined as above to provide a series of polypeptides.

[0093] The present invention has the sequence shown below: YX0QGT FTSDY SIX1LD K 1 KAQX0 1 KFIEF LLEGG PSSGA PPPS‐NH2 YX0QGT FTSDY SIX1LD K 1 KAQX0 1 KFIEF LIEGG PSSGA PPPS‐NH2 YX0QGT FTSDY SIX1LD K 1 KAQX0 1 KFVEF LIEGG PSSGA PPPS‐NH2 YX0QGT FTSDY SIX1LD KKAQX0AFIE 1 KFI 1 KGG PSSGA PPPS‐NH2 YX0QGT FTSDY SIX1LD KKAQX0 1KFIEF LL 1 KGG PSSGA PPPS‐NH2 YX0QGT FTSDY SIX0LD K 1 KAQX0 1 KFIEF LLEGG PSSGA PPPS‐NH2 YX0QGT FTSDY S 1 KX1LD 1 KKAQX0AFIEF LLEGG PSSGA PPPS‐NH2

[0094] where S0 is The group shown in TIFF2026503073000069.tif21170 (i.e., the C-terminal amino acid is amidated to a C-terminal primary amide), and X0, X1, and S0 and the modification schemes were defined as above to provide a series of polypeptides.

[0095] The present invention relates to a method for producing a nucleic acid sequence having a sequence shown as follows, wherein a part of X0 is Aib, YX0QGT FTSDY SIX1LD K 1 KAQAib 1 KFIEF LLEGG PSSGA PPPS‐NH2 YX0QGT FTSDY SIX1LD K 1 KAQAib 1 KFIEF LIEGG PSSGA PPPS‐NH2 YX0QGT FTSDY SIX1LD K 1 KAQAib 1 KFVEF LIEGG PSSGA PPPS‐NH2 YX0QGT FTSDY SIX1LD KKAQAib AFIE 1 KFI 1 KGG PSSGA PPPS‐NH2 YX0QGT FTSDY SIX1LD KKAQAib 1 KFIEF LL 1 KGG PSSGA PPPS‐NH2 YX0QGT FTSDY SIAibLD K 1 KAQAib 1KFIEF LLEGG PSSGA PPPS‐NH2 YX0QGT FTSDY S 1 KX1LD 1 KKAQAib AFIEF LLEGG PSSGA PPPS‐NH2 The other variables provided a range of polypeptides as defined above.

[0096] The present invention relates to a method for producing a nucleotide sequence of a nucleotide analogue of a nucleotide analogue having a sequence shown as follows: YAibQGT FTSDY SIX1LD K 1 KAQAib 1 KFIEF LLEGG PSSGA PPPS‐NH2 YAibQGT FTSDY SIX1LD K 1 KAQAib 1 KFIEF LIEGG PSSGA PPPS‐NH2 YAibQGT FTSDY SIX1LD K 1 KAQAib 1 KFVEF LIEGG PSSGA PPPS‐NH2 YAibQGT FTSDY SIX1LD KKAQAib AFIE 1 KFI 1 KGG PSSGA PPPS‐NH2 YAibQGT FTSDY SIX1LD KKAQAib 1 KFIEF LL 1 KGG PSSGA PPPS‐NH2 YAibQGT FTSDY SIAibLD K 1 KAQAib 1 KFIEF LLEGG PSSGA PPPS‐NH2 YAibQGT FTSDY S 1 KX1LD 1 KKAQAib AFIEF LLEGG PSSGA PPPS‐NH2 The other variables provided a range of polypeptides as defined above.

[0097] The present invention relates to a polypeptide having a sequence as shown below: YX0QGT FTSDY SIX1 1 KDK 1 KAQX0AFIEY LLEGG PSSGA PPPS‐NH2 where: S0 is TIFF2026503073000070.tif22170 (i.e., the C-terminal amino acid is amidated to a C-terminal primary amide), X0 is TIFF2026503073000071.tif16170 or Aib, and the structure of Aib above is TIFF2026503073000072.tif16170X1 is α-methyl-substituted leucine (α-MeLeu, α-MeL), and its structure is TIFF2026503073000073.tif17170 The superscripts in the sequence refer to modified amino acid unit structures, and amino acids with the same superscript number are linked by modification to form amino acid unit structures similar to the "staple" structure, for example, 1 K and 1 K represents a modified lysine, and the two are linked by a modification group (K-K modification). The above modifications involve modifying the amino or carboxyl groups on the side chains of the two amino acid unit structures. TIFF2026503073000074.tif14170 and is linked by condensation with the group represented by the formula X2 is TIFF2026503073000075.tif40170, wherein "*" indicates the position linked to X3, and both ends are positions linked to the corresponding amino group or carboxyl group of the modified amino acid; X3 is selected from the group shown in TIFF2026503073000076.tif135170; A series of polypeptides were provided in which m is selected from 1, 2 or 3; p is selected from 1 or 2; and n is selected from 8, 9 or 10.

[0098] The present invention relates to a polypeptide having a sequence as shown below: TIFF2026503073000077.tif113170 where, S0 is TIFF2026503073000078.tif21170 (i.e., the C-terminal amino acid is amidated to a C-terminal primary amide), X0 is TIFF2026503073000079.tif16170 or Aib, and the structure of Aib above is TIFF2026503073000080.tif16170X1 has the following structure: α-methyl-substituted leucine (α-MeLeu, α-MeL), which is a group represented by TIFF2026503073000081.tif17170; X4 has a structure α-methyl-substituted lysine (α-MeLys, α-MeK), a group represented by TIFF2026503073000082.tif22170, the structure of which is D-lysine (d-K), a group represented by TIFF2026503073000083.tif22170, or the structure independently selected from L-ornithine (L-Orn), a group represented by TIFF2026503073000084.tif23170; The superscripts in the sequences refer to modified amino acid unit structures, where amino acids with the same superscript number are linked by a modifying group to form an amino acid unit structure similar to the "staple" structure, e.g., 1 K and 1 E represents a modified lysine and glutamic acid, which are linked by a modification group (KE modification). 1 K and 1 K represents a modified lysine, and both are linked by a modifying group (K-K modification). 1 K and 1X4 represents a modified lysine and X4, which are linked by a modification group (K-X4 modification); The above modifications involve modifying the amino or carboxyl groups on the side chains of the two amino acid unit structures. TIFF2026503073000085.tif14170 and is linked by condensation with the group represented by the formula X2 is TIFF2026503073000086.tif40170, wherein "*" indicates the position linked to X3, and both ends are positions linked to the corresponding amino group or carboxyl group of the modified amino acid; X3 is selected from the group shown in TIFF2026503073000087.tif130170; A series of polypeptides were provided in which m is selected from 1, 2 or 3; p is selected from 1 or 2; and n is selected from 8, 9 or 10.

[0099] The present invention relates to a polypeptide having a sequence as shown below: TIFF2026503073000088.tif69170 where, X0 is TIFF2026503073000089.tif16170 or Aib, and the structure of Aib above is TIFF2026503073000090.tif16170X1 has the following structure: α-methyl-substituted leucine (α-MeLeu, α-MeL), which is a group represented by TIFF2026503073000091.tif17170; The superscripts in the sequences refer to modified amino acid unit structures, where amino acids with the same superscript number are linked by a modifying group to form an amino acid unit structure similar to the "staple" structure, e.g., 1 K and 1 E represents a modified lysine and glutamic acid, which are linked by a modification group (KE modification). 1 K and 1K represents a modified lysine, and the two are linked by a modification group (K-K modification). The above modifications involve modifying the amino or carboxyl groups on the side chains of the two amino acid unit structures. TIFF2026503073000092.tif14170 and is linked by condensation with the group represented by the formula X2 is TIFF2026503073000093.tif40170, wherein "*" indicates the position linked to X3, and both ends are positions linked to the corresponding amino group or carboxyl group of the modified amino acid; X3 is selected from the group shown in TIFF2026503073000094.tif130170; Further provided is a series of polypeptides wherein m is selected from 1, 2 or 3; p is selected from 1 or 2; and n is selected from 8, 9 or 10.

[0100] In some aspects of the present invention, a polypeptide having the above modified structure has a peptide chain sequence shown below: TIFF2026503073000095.tif69170 The other variables are as defined herein.

[0101] In some aspects of the present invention, a polypeptide having the above modified structure has a peptide chain sequence shown below: YX0QGT FTSDY SIX1LD K 1 KAQAib 1 KFIEF LLEGG PSSGA PPPS‐NH2 YX0QGT FTSDY SIX1LD K 1 KAQAib 1 EFIEY LLEGG PSSGA PPPS‐NH2 YX0QGT FTSDY SIX1LD K 1 KAQAib AFI 1 KY LLEGG PSSGA PPPS‐NH2 YX0QGT FTSDY SIX1LD K1 KAQAib 1 KFIEY LLEGG PSSGA PPPS‐NH2 YX0QGT FTSDY SIX1LD KKA 1 KAib AFI 1 KY LLEGG PSSGA PPPS‐NH2 YX0QGT FTSDY SIX1LD KKAQAib 1 KFIEY LL 1 KGG PSSGA PPPS‐NH2 YX0QGT FTSDY SIX1LD K 1 KAQA 1 X4FIEY LLEGG PSSGA PPPS‐NH2 YX0QGT FTSDY SIX1LD K 1 KAQAib 1 X4FIEY LLEGG PSSGA PPPS‐NH2 YX0QGT FTSDY SIX1LD K 1 KAQAib 1 X4FIEY LLEGG PSSGA PPPS‐NH2 The other variables are as defined in the present invention.

[0102] In some aspects of the present invention, a polypeptide having the above modified structure has a peptide chain sequence shown below: YX0QGT FTSDY SIX1 1 KDK 1 KAQAib AFIEY LLEGG PSSGA PPPS-NH2 The other variables are as defined in the present invention.

[0103] In some aspects of the present invention, a polypeptide having the above-described modified structure has a peptide chain sequence shown in any one of the following: YX0QGT FTSDY SIX1 1 KDK 1 KAQAib EFIEY LLEGG PSSGA PPPS‐NH2 YX0QGT FTSDY SIX1 1KDK 1 KAQAib AFIEY LLKGG PSSGA PPPS‐NH2 The other variables are as defined in the present invention.

[0104] In some aspects of the present invention, the polypeptide having the above modified structure has all of X0 being Aib and X1 being α-MeL, i.e., the peptide chain sequence is shown in any of the following: YAibQGT FTSDY SIX1 1 KDK 1 KAQAib EFIEY LLEGG PSSGA PPPS‐NH2 YAibQGT FTSDY SIX1 1 KDK 1 KAQAib AFIEY LLKGG PSSGA PPPS‐NH2 The other variables are as defined in the present invention.

[0105] In some aspects of the present invention, the polypeptide having the above modified structure has all of X0 being Aib and X1 being α-MeL, i.e., the peptide chain sequence is as shown below: TIFF2026503073000096.tif74170

[0106] In some aspects of the present invention, the polypeptide having the above modified structure has all of X0's being Aib, and the peptide chain sequence is as shown below: YAibQGT FTSDY SIX1LD K 1 KAQAib 1 KFIEF LLEGG PSSGA PPPS‐NH2 YAibQGT FTSDY SIX1LD K 1 KAQAib 1 EFIEY LLEGG PSSGA PPPS‐NH2 YAibQGT FTSDY SIX1LD K 1 KAQAib AFI 1 KY LLEGG PSSGA PPPS‐NH2 YAibQGT FTSDY SIX1LD K 1 KAQAib 1 KFIEY LLEGG PSSGA PPPS‐NH2 YAibQGT FTSDY SIX1LD KKA 1 KAib AFI 1 KY LLEGG PSSGA PPPS‐NH2 YAibQGT FTSDY SIX1LD KKAQAib 1 KFIEY LL 1 KGG PSSGA PPPS‐NH2 YAibQGT FTSDY SIX1LD K 1 KAQA 1 X4KFIEY LLEGG PSSGA PPPS‐NH2 YAibQGT FTSDY SIX1LD K 1 KAQAib 1 X4FIEY LLEGG PSSGA PPPS‐NH2 YAibQGT FTSDY SIX1LD K 1 KAQAib 1 X4FIEY LLEGG PSSGA PPPS‐NH2 The other variables are as defined in the present invention.

[0107] In some aspects of the present invention, the polypeptide having the above modified structure is one in which X1 is α-MeL and the peptide chain sequence is as shown below: YAibQGT FTSDY SIX1LD K 1 KAQAib 1 KFIEF LLEGG PSSGA PPPS‐NH2 YAibQGT FTSDY SIX1LD K 1 KAQAib 1 EFIEY LLEGG PSSGA PPPS‐NH2 YAibQGT FTSDY SIX1LD K 1 KAQAib AFI 1 KY LLEGG PSSGA PPPS‐NH2 YAibQGT FTSDY SIX1LD K1 KAQAib 1 KFIEY LLEGG PSSGA PPPS‐NH2 YAibQGT FTSDY SIX1LD KKA 1 KAib AFI 1 KY LLEGG PSSGA PPPS‐NH2 YAibQGT FTSDY SIX1LD KKAQAib 1 KFIEY LL 1 KGG PSSGA PPPS‐NH2 YAibQGT FTSDY SIX1LD K 1 KAQA 1 α‐MeKFIEY LLEGG PSSGA PPPS‐NH2 YAibQGT FTSDY SIX1LD K 1 KAQAib 1 d‐KFIEY LLEGG PSSGA PPPS‐NH2 YAibQGT FTSDY SIX1LD K 1 KAQAib 1 L‐OrnFIEY LLEGG PSSGA PPPS‐NH2 The other variables are as defined in the present invention.

[0108] In some aspects of the present invention, the polypeptide having the above modified structure has all of X0's being Aib, and the peptide chain sequence is as shown below: YAibQGT FTSDY SIX1 1 KDK 1 KAQAib AFIEY LLEGG PSSGA PPPS-NH2 The other variables are as defined in the present invention.

[0109] The present invention provides a polypeptide having a series of modified structures or a pharmaceutically acceptable salt thereof, YX0QGT FTSDY SIX1LD KKAQX0 1 KFVEF LL 1 KGG PSSGA PPPS0 YX0QGT FTSDY SIX1LD KKAQX0 1 KFVEF LI 1 KGG PSSGA PPPS0 YX0QGT FTSDY SIX1LD K 1 KAQX0 1 KFIEF LLKGG PSSGA PPPS0 YX0QGT FTSDY SIX1LD K 1 KAQX0 1 KFIKF LLEGG PSSGA PPPS0 YX0QGT FTSDY S 1 KX1LD 1 KKAQX0KFIEF LLEGG PSSGA PPPS0 and the compound includes the following modifications: The above modifications involve modifying the amino or carboxyl groups on the side chains of the two amino acid unit structures. TIFF2026503073000097.tif14170 and is linked by condensation with the group represented by the formula X2 is TIFF2026503073000098.tif40170, wherein "*" indicates the position linked to X3, and both ends are positions linked to the corresponding amino group or carboxyl group of the modified amino acid; X3 is selected from the group shown in TIFF2026503073000099.tif128170; Further provided are polypeptides or pharmaceutically acceptable salts thereof having a series of modified structures, wherein m is selected from 1, 2, or 3, p is selected from 1, 2, and n is selected from 8, 9, or 10, and the other variables are as defined herein.

[0110] In some aspects of the present invention, the polypeptide or pharmaceutically acceptable salt thereof having the above-described modified structure has a peptide chain sequence as shown below: YX0QGT FTSDY SIX1LD KKAQX0 1 KFVEF LL 1KGG PSSGA PPPS‐NH2 YX0QGT FTSDY SIX1LD KKAQX0 1 KFVEF LI 1 KGG PSSGA PPPS‐NH2 YX0QGT FTSDY SIX1LD K 1 KAQX0 1 KFIEF LLKGG PSSGA PPPS‐NH2 YX0QGT FTSDY SIX1LD K 1 KAQX0 1 KFIKF LLEGG PSSGA PPPS‐NH2 YX0QGT FTSDY S 1 KX1LD 1 KKAQX0KFIEF LLEGG PSSGA PPPS‐NH2 The other variables are as defined in the present invention.

[0111] In some aspects of the present invention, for the polypeptide or pharmaceutically acceptable salt thereof having the above modified structure, a portion of X is Aib, that is, the peptide chain sequence is as shown below: YAibQGT FTSDY SIX1LD KKAQX0 1 KFVEF LL 1 KGG PSSGA PPPS‐NH2 YAibQGT FTSDY SIX1LD KKAQX0 1 KFVEF LI 1 KGG PSSGA PPPS‐NH2 YAibQGT FTSDY SIX1LD K 1 KAQX0 1 KFIEF LLKGG PSSGA PPPS‐NH2 YAibQGT FTSDY SIX1LD K 1 KAQX0 1 KFIKF LLEGG PSSGA PPPS‐NH2 YAibQGT FTSDY S 1 KX1LD 1 KKAQX0KFIEF LLEGG PSSGA PPPS‐NH2 The other variables are as defined in the present invention.

[0112] In some aspects of the present invention, for the polypeptide or pharmaceutically acceptable salt thereof having the above modified structure, all of X0 are Aib and X1 is α-MeL, i.e., the peptide chain sequence is as shown below: YAibQGT FTSDY SIX1LD KKAQAib 1 KFVEF LL 1 KGG PSSGA PPPS‐NH2 YAibQGT FTSDY SIX1LD KKAQAib 1 KFVEF LI 1 KGG PSSGA PPPS‐NH2 YAibQGT FTSDY SIX1LD K 1 KAQAib 1 KFIEF LLKGG PSSGA PPPS‐NH2 YAibQGT FTSDY SIX1LD K 1 KAQAib 1 KFIKF LLEGG PSSGA PPPS‐NH2 YAibQGT FTSDY S 1 KX1LD 1 KKAQAibKFIEF LLEGG PSSGA PPPS‐NH2 The other variables are as defined in the present invention.

[0113] In some aspects of the present invention, the polypeptide or pharmaceutically acceptable salt thereof having the above-described modified structure has a peptide chain sequence as shown below: YX0QGT FTSDY SIX1 1 KDK 1 KAQX0AFIQY LLEGG PSSGA PPPS‐NH2 The other variables are as defined in the present invention.

[0114] In some aspects of the present invention, in the polypeptide having the above modified structure or a pharmaceutically acceptable salt thereof, part of X0 is Aib. 、 The peptide chain sequence is shown below: YAibQGT FTSDY SIX1 1 KDK 1 KAQX0AFIQY LLEGG PSSGA PPPS‐NH2 The other variables are as defined in the present invention.

[0115] In some aspects of the present invention, in the polypeptide having the above-described modified structure or a pharmaceutically acceptable salt thereof, all of X0 are Aib, X1 is α-MeL, and the peptide chain sequence is as shown below: YAibQGT FTSDY SIX1 1 KDK 1 KAQAibAFIQY LLEGG PSSGA PPPS‐NH2 The other variables are as defined in the present invention.

[0116] In some aspects of the invention, m above is selected from 1 or 2, and the other variables are as defined herein.

[0117] In some aspects of the invention, p above is selected from 1, and the other variables are as defined herein.

[0118] In some aspects of the invention, n above is selected from 9, and the other variables are as defined herein.

[0119] In some aspects of the present invention, X3 is TIFF2026503073000100.tif98170, and other variables are as defined herein.

[0120] In some aspects of the present invention, The structural unit shown in TIFF2026503073000101.tif13170 is TIFF2026503073000102.tif26170, and other variables are as defined herein.

[0121] In some aspects of the present invention, The structural unit shown in TIFF2026503073000103.tif13170 is TIFF2026503073000104.tif29170, and other variables are as defined herein.

[0122] In some aspects of the present invention, The structural unit shown in TIFF2026503073000105.tif14170 is TIFF2026503073000106.tif29170, and other variables are as defined herein.

[0123] In some aspects of the present invention, The structural unit shown in TIFF2026503073000107.tif13170 is TIFF2026503073000108.tif31170, and other variables are as defined herein.

[0124] In some aspects of the present invention, The structural unit shown in TIFF2026503073000109.tif14170 is TIFF2026503073000110.tif32170, and other variables are as defined herein.

[0125] In some aspects of the present invention, The structural unit shown in TIFF2026503073000111.tif14170 is TIFF2026503073000112.tif30170, and other variables are as defined herein.

[0126] In some aspects of the present invention, The structural unit shown in TIFF2026503073000113.tif13170 is TIFF2026503073000114.tif23170, and other variables are as defined herein.

[0127] In some aspects of the present invention, The structural unit shown in TIFF2026503073000115.tif13170 is TIFF2026503073000116.tif24170, and other variables are as defined herein.

[0128] In some aspects of the present invention, The structural unit shown in TIFF2026503073000117.tif13170 is TIFF2026503073000118.tif28170, and other variables are as defined herein.

[0129] In some aspects of the present invention, the "staple" structure (staple body) in a polypeptide having the above modified structure is a group represented by any of the following formulas, wherein the other variables are as defined herein: TIFF2026503073000119.tif209170TIFF2026503073000120.tif174170

[0130] In some aspects of the present invention, the "staple" structure (staple body) in a polypeptide having the above modified structure is a group represented by any of the following formulas, wherein the other variables are as defined herein: TIFF2026503073000121.tif211170TIFF2026503073000122.tif81170

[0131] In some aspects of the present invention, the "staple" structure (staple body) in a polypeptide having the above modified structure is a group represented by any of the following formulas, wherein the other variables are as defined herein: TIFF2026503073000123.tif204170

[0132] In some aspects of the present invention, the "staple" structure (staple body) in a polypeptide having the above modified structure is a group represented by any of the following formulas, wherein the other variables are as defined herein: TIFF2026503073000124.tif147170

[0133] In some aspects of the present invention, the "staple" structure (staple body) in a polypeptide having the above modified structure is a group represented by any of the following formulas, wherein the other variables are as defined herein: TIFF2026503073000125.tif49170

[0134] In some aspects of the present invention, the "staple" structure (staple body) in a polypeptide having the above modified structure is a group represented by any of the following formulas, wherein the other variables are as defined herein: TIFF2026503073000126.tif151170

[0135] In some aspects of the present invention, the "staple" structure (staple body) in a polypeptide having the above modified structure is a group represented by the following formula, wherein the other variables are as defined herein: TIFF2026503073000127.tif56170

[0136] In some specific embodiments of the present invention, the structure of the polypeptide having the modified structure is shown in Table 1 below, and the structure of Aib above is TIFF2026503073000128.tif16170The above α-MeL is α-methyl-substituted leucine, and its structure is TIFF2026503073000129.tif17170The above α-MeK is an α-methyl-substituted lysine, and its structure is represented by the formula TIFF2026503073000130.tif23170Other variables are as defined herein, for example, superscripts in the sequence refer to modified amino acid unit structures, and indicate that amino acids with the same superscript number are linked by a modifying group to form an amino acid unit structure similar to the "staple" structure.

[0137] TIFF2026503073000131.tif225170TIFF2026503073000132.tif187170

[0138] In some specific embodiments of the present invention, the structure of the polypeptide having the modified structure is shown in Table 2 below, and the structure of Aib above is TIFF2026503073000133.tif16170The above α-MeL is α-methyl-substituted leucine, and its structure is TIFF2026503073000134.tif17170The above α-MeK is an α-methyl-substituted lysine, and its structure is TIFF2026503073000135.tif22170The above d-K is D-lysine, and its structure is TIFF2026503073000136.tif24170The above L-Ornithine or L-Orn is L-ornithine, and its structure is TIFF2026503073000137.tif23170Other variables are as defined herein, for example, superscripts in the sequence indicate modified amino acid unit structures, and indicate that amino acids with the same superscript number are linked by a modifying group to form an amino acid unit structure similar to the "staple" (staple body) structure.

[0139] TIFF2026503073000138.tif245170TIFF2026503073000139.tif228170TIFF2026503073000140.tif57170

[0140] In some specific embodiments of the present invention, the structure of the polypeptide having the modified structure is shown in Table 3 below, and the structure of Aib above is TIFF2026503073000141.tif16170The above α-MeL is α-methyl-substituted leucine, and its structure is TIFF2026503073000142.tif17170The above α-MeK is an α-methyl-substituted lysine, and its structure is TIFF2026503073000143.tif23170Other variables are as defined herein, for example, superscripts in the sequence refer to modified amino acid unit structures, and indicate that amino acids with the same superscript number are linked by a modifying group to form an amino acid unit structure similar to the "staple" structure.

[0141] TIFF2026503073000144.tif216170

[0142] In some specific embodiments of the present invention, X1 is α-MeL, and the structure of the polypeptide having the modified structure is shown in Table 4 below, and the structure of Aib above is TIFF2026503073000145.tif16170The above α-MeL is α-methyl-substituted leucine, and its structure is TIFF2026503073000146.tif17170Other variables are as defined herein, for example, superscripts in the sequence refer to modified amino acid unit structures, and indicate that amino acids with the same superscript number are linked by a modifying group to form an amino acid unit structure similar to the "staple" structure.

[0143] TIFF2026503073000147.tif238170TIFF2026503073000148.tif94170

[0144] In some specific embodiments of the present invention, X1 is α-MeL, and the structures of polypeptides with modified structures are shown in Table 5 below.

[0145] TIFF2026503073000149.tif229170TIFF2026503073000150.tif138170

[0146] In some specific embodiments of the present invention, X1 is α-MeL, and the structures of polypeptides with modified structures are shown in Table 6 below.

[0147] TIFF2026503073000151.tif199170TIFF2026503073000152.tif172170

[0148] In some aspects of the present invention, the "staple" structure (staple body) in a polypeptide having the above modified structure is a group represented by the following formula, wherein the other variables are as defined herein: TIFF2026503073000153.tif161170

[0149] In some specific embodiments of the present invention, X1 is α-MeL, and the structures of polypeptides with modified structures are shown in Table 7 below.

[0150] TIFF2026503073000154.tif200170

[0151] In some aspects of the present invention, the polypeptide or pharmaceutically acceptable salt thereof having the above-described modified structure has a peptide chain sequence as shown below: YX0QGT FTSDY SIX1 1 KDK 1 KAQX0KFIEY LLEGG PSSGA PPPS‐NH2 YX0QGT FTSDY SIX1 1 KDK 1 KAQX0LFIEY LLEGG PSSGA PPPS‐NH2 YX0QGT a‐MeFTSDY SIX1 1 KDK 1 KAQX0AFIEY LLEGG PSSGA PPPS‐NH2 YX0QGT a‐MeFTSDY SIX1 1 KDK 1 KAQX0AFIEY LLKGG PSSGA PPPS‐NH2 The other variables are as defined in the present invention.

[0152] In some aspects of the present invention, in the polypeptide having the above modified structure or a pharmaceutically acceptable salt thereof, part of X0 is Aib, and the peptide chain sequence is as shown below: YAibQGT FTSDY SIX1 1 KDK 1 KAQX0KFIEY LLEGG PSSGA PPPS‐NH2 YAibQGT FTSDY SIX1 1 KDK 1 KAQX0LFIEY LLEGG PSSGA PPPS‐NH2 YAibQGT a‐MeFTSDY SIX1 1 KDK 1 KAQX0AFIEY LLEGG PSSGA PPPS‐NH2 YAibQGT a‐MeFTSDY SIX1 1 KDK 1 KAQX0AFIEY LLKGG PSSGA PPPS‐NH2 The other variables are as defined in the present invention.

[0153] In some aspects of the present invention, in the polypeptide having the above modified structure or a pharmaceutically acceptable salt thereof, all of X0 are Aib, X1 is α-MeL, and the peptide chain sequence is as shown below: YAibQGT FTSDY SIX1 1 KDK 1 KAQAib KFIEY LLEGG PSSGA PPPS‐NH2 YAibQGT FTSDY SIX1 1 KDK 1 KAQAib LFIEY LLEGG PSSGA PPPS‐NH2 YAibQGT a‐MeFTSDY SIX1 1 KDK 1 KAQAib AFIEY LLEGG PSSGA PPPS-NH2 YAibQGT a‐MeF TSDY SIX1 1 KDK 1 KAQAib AFIEY LLKGG PSSGA PPPS‐NH2 The other variables are as defined in the present invention.

[0154] In some aspects of the present invention, the "staple" structure (staple body) in a polypeptide having the above modified structure is a group represented by the following formula, wherein the other variables are as defined herein: TIFF2026503073000155.tif147170

[0155] In some specific embodiments of the present invention, the structures of polypeptide compounds having modified structures are shown in Table 8 below.

[0156] TIFF2026503073000156.tif206170TIFF2026503073000157.tif236170TIFF2026503073000158.tif112170

[0157] The present invention further provides a pharmaceutical composition comprising, as an active ingredient, a therapeutically effective amount of the above polypeptide compound or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier.

[0158] In some aspects of the present invention, there is provided use of the above-mentioned polypeptide or a pharmaceutically acceptable salt thereof, or the above-mentioned pharmaceutical composition in the preparation of a medicament for preventing or treating metabolic diseases and their associated diseases.

[0159] In some aspects of the present invention, there is provided use of the above-mentioned polypeptide or a pharmaceutically acceptable salt thereof, or the above-mentioned pharmaceutical composition in the preparation of a medicament for preventing or treating diabetes and its related diseases.

[0160] In some aspects of the present invention, there is provided use of the above-mentioned polypeptide or a pharmaceutically acceptable salt thereof, or the above-mentioned pharmaceutical composition in the preparation of a medicament for preventing or treating obesity and its related diseases.

[0161] In some aspects of the present invention, there is provided use of the above-mentioned polypeptide or a pharmaceutically acceptable salt thereof, or the above-mentioned pharmaceutical composition in the preparation of a medicament for preventing or treating NASH (non-alcoholic steatohepatitis) and its related diseases. Technical effects

[0162] The polypeptides of the present invention have strong agonist activity against GLP-1R / GIPR / GCGR in vitro, and the compounds of the present invention have excellent in vitro and in vivo pharmacokinetic properties and have significant effects on weight loss, hypoglycemic effects, and hypolipidemic effects. Definitions and Explanations

[0163] Unless otherwise specified, the following terms and phrases used herein shall have the following meanings: A particular term or phrase should not be considered unclear or ambiguous unless specifically defined, and should be understood according to its ordinary meaning. When trade names are mentioned herein, it is intended to refer to the corresponding product or its active ingredients.

[0164] The terms "polypeptide", "peptide" and "polypeptide compound" used in the present invention can be understood to have the same meaning by those skilled in the art by referring to the context, unless otherwise specified.

[0165] The terms "polypeptide sequence" and "peptide chain" described in the present invention can be understood to have the same meaning by those skilled in the art by referring to the context, unless otherwise specified.

[0166] Unless otherwise specified, the terms "staple" and "staple body" described in the present invention can be understood to have the same meaning by those skilled in the art by referring to the context. Unless otherwise specified, the numbering of the examples of compounds in the present invention is the same as the numbering of the compounds described above. That is, the compounds shown as "Example 1" and "Compound 1" above are compounds of the same structure.

[0167] As used herein, the term "pharmaceutically acceptable" refers to compounds, materials, compositions and / or dosage forms that are, within the scope of sound medical judgment, suitable for use in contact with human and animal tissues and without undue toxicity, irritation, allergic response, other problem or complication, commensurate with a reasonable benefit / risk ratio.

[0168] The term "pharmaceutically acceptable salt" refers to a salt of a compound of the present invention prepared from a compound having certain substituents found in the present invention and a relatively non-toxic acid or base. When a compound of the present invention contains a relatively acidic functional group, a base addition salt can be obtained by contacting such a compound with a sufficient amount of base in a pure solution or in a suitable inert solvent. Pharmaceutically acceptable base addition salts include sodium salts, potassium salts, calcium salts, ammonium salts, organic amine or magnesium salts, or similar salts. When a compound of the present invention contains a relatively basic functional group, an acid addition salt can be obtained by contacting such a compound with a sufficient amount of acid in a pure solution or in a suitable inert solvent. Examples of pharmaceutically acceptable acid addition salts include inorganic acid salts such as hydrochloric acid, hydrobromic acid, nitric acid, carbonic acid, bicarbonate, phosphoric acid, monohydrogen phosphate, dihydrogen phosphate, sulfuric acid, hydrogen sulfate, hydroiodic acid, phosphorous acid, and the like, and organic acid salts such as acetic acid, trifluoroacetic acid, propionic acid, isobutyric acid, maleic acid, malonic acid, benzoic acid, succinic acid, suberic acid, fumaric acid, lactic acid, mandelic acid, phthalic acid, benzenesulfonic acid, p-toluenesulfonic acid, citric acid, tartaric acid, methanesulfonic acid, pamoic acid, and the like, as well as salts of amino acids (such as arginine) and organic acids such as glucuronic acid. Some specific compounds of the present invention contain both basic and acidic functional groups and can therefore be converted into either base or acid addition salts.

[0169] The pharmaceutically acceptable salts of the present invention can be synthesized from a parent compound containing an acid or base using conventional chemical methods. Generally, such salts are prepared by reacting the compound in its free acid or base form with a stoichiometric amount of the appropriate base or acid in water, an organic solvent, or a mixture thereof.

[0170] "Amino acid" refers to naturally occurring and synthetic amino acids, as well as amino acid analogs and amino acid mimetics that function similarly to naturally occurring amino acids. Naturally occurring amino acids are those encoded by the genetic code, as well as those amino acids that have been subsequently modified, such as hydroxyproline, γ-carboxyglutamine, and O-phosphoserine. Amino acid analogs refer to compounds that have the same basic chemical structure (e.g., an α-carbon bonded to a hydrogen, carboxyl group, amino group, and R group) as naturally occurring amino acids, such as homoserine, norleucine, methionine sulfoxide, and methionine methylsulfonium. Such analogs may have modified R groups (e.g., norleucine) or modified peptide backbones, but retain the same basic chemical structure as naturally occurring amino acids. Amino acid mimetics refer to chemical compounds that have a structure different from the general chemical structure of an amino acid, but that function similarly to a naturally occurring amino acid.

[0171] The natural amino acids and their various representations described herein are well known to those skilled in the art, and details thereof are provided in the table below. TIFF2026503073000159.tif247170TIFF2026503073000160.tif110170

[0172] Other unnatural amino acids, such as 2-aminoisobutyric acid (Aib), correspond to the table below. TIFF2026503073000161.tif124170

[0173] The term "treatment" includes inhibiting, slowing, halting or reversing the progression or severity of an existing condition or disease.

[0174] Unless otherwise specified, the term "isomer" is intended to include geometric isomers, cis-trans isomers, stereoisomers, enantiomers, optical isomers, diastereomers and tautomers.

[0175] The compounds of the present invention can exist in specific geometric or stereoisomeric forms. The present invention contemplates all of these compounds, including cis and trans isomers, (-)- and (+)-enantiomers, (R)- and (S)-enantiomers, diastereomers, (D)-isomers, (L)-isomers, and racemic and other mixtures thereof, such as enantiomerically or diastereomerically enriched mixtures, and all such mixtures are within the scope of the present invention. Substituents such as alkyl may have additional asymmetric carbon atoms. All of these isomers and mixtures thereof are within the scope of the present invention.

[0176] Unless otherwise specified, the terms "enantiomers" or "optical isomers" refer to stereoisomers that are mirror images of each other.

[0177] Unless otherwise specified, the term "cis-trans isomers" or "geometric isomers" refers to isomers resulting from the inability to freely rotate about a double bond or a single bond of a ring-forming carbon atom.

[0178] Unless otherwise specified, the term "diastereomer" means a stereoisomer whose molecules have two or more centers of chirality and which are not mirror-image related to one another.

[0179] Unless otherwise specified, "(+)" denotes dextrorotatory, "(-)" denotes levorotatory, and "(±)" denotes racemic.

[0180] Unless otherwise noted, TIFF2026503073000162.tif48170

[0181] Unless otherwise specified, the terms "enriched in one isomer," "enriched isomer," "enriched in one enantiomer," or "enantiomerically enriched" mean that the content of one isomer or enantiomer is less than 100% and is 60% or more, or 70% or more, or 80% or more, or 90% or more, or 95% or more, or 96% or more, or 97% or more, or 98% or more, or 99% or more, or 99.5% or more, or 99.6% or more, or 99.7% or more, or 99.8% or more, or 99.9% or more.

[0182] Unless otherwise specified, the terms "isomeric excess" or "enantiomeric excess" refer to the relative percentage difference between two isomers or two enantiomers. For example, if one isomer or enantiomer is 90% and the other isomer or enantiomer is 10%, the isomeric or enantiomeric excess (ee) is 80%.

[0183] Optically active (R)- and (S)-isomers and D- and L-isomers can be prepared using chiral synthesis, chiral reagents, or other conventional techniques. Single enantiomers of certain compounds of the invention can be prepared by asymmetric synthesis or derivatization with a chiral auxiliary, where the resulting diastereomeric mixture is separated and the auxiliary is cleaved to provide the desired pure enantiomer. Alternatively, if the molecule contains a basic (e.g., amino) or acidic (e.g., carboxy) functional group, the diastereomeric salt can be formed with an appropriate optically active acid or base, followed by separation of the diastereomers by conventional methods known in the art and subsequent recovery to provide the pure enantiomers. Separation of enantiomers and diastereomers is also typically accomplished by chromatographic methods using chiral stationary phases, optionally in combination with chemical derivatization (e.g., carbamate formation from an amine).

[0184] The compounds of the present invention may contain unnatural proportions of atomic isotopes at one or more of the atoms that constitute such compounds. For example, tritium ( 3H), iodine-125( 125 I) or C-14( 14 Compounds can be labeled with radioactive isotopes such as C). For example, hydrogen can be replaced with deuterium to form deuterated drugs. The bond between deuterium and carbon is stronger than the bond between normal hydrogen and carbon, and deuterated drugs have advantages over non-deuterated drugs, such as reduced toxicity and side effects, increased drug stability, enhanced therapeutic efficacy, and extended biological half-life. All isotopic variations of the compounds of the present invention, whether radioactive or not, are within the scope of the present invention.

[0185] In the case of the linking group listed, if the linking direction is not indicated, the linking direction is arbitrary, for example, When the linking group L in TIFF2026503073000163.tif15170 is -M-W-, -M-W- connects ring A and ring B in the same direction as the reading order from left to right. You can construct TIFF2026503073000164.tif17170 and concatenate rings A and B in the opposite left-to-right reading order. TIFF2026503073000165.tif17170. Combinations of the above linking groups, substituents and / or variants thereof are permissible only if such combinations result in stable compounds.

[0186] Unless otherwise specified, when a group has one or more linkable sites, any one or more of the sites of the group can be linked to other groups via chemical bonds.If the linking mode of the chemical bond is non-directional and there is an H atom at the linkable site, when the chemical bond is linked, the number of H atoms at the site will decrease according to the number of linked chemical bonds, forming a group with the corresponding valence.The chemical bond between the above site and other groups is: For example, the linear solid bond of -OCH3 represents a bond to another group via the oxygen atom of that group, The straight broken bond in the group shown in TIFF2026503073000167.tif9170 indicates that the nitrogen atom of the group is connected to other groups at both ends thereof. The wavy lines in the group shown in TIFF2026503073000168.tif17170 indicate that the phenyl group is linked to another group via the 1st and 2nd carbon atoms.

[0187] Unless otherwise specified, "C 1‐3 The term "alkyl" is used to denote a linear or branched saturated hydrocarbon group consisting of 1 to 3 carbon atoms. 1‐3 Alkyl is C 1‐2 and C 2‐3 alkyl, etc., and may be monovalent (e.g., methyl), divalent (e.g., methylene), or polyvalent (e.g., methylidyne). 1‐3 Examples of alkyl include, but are not limited to, methyl (Me), ethyl (Et), propyl (including n-propyl and isopropyl) groups, and the like.

[0188] The structure of the compound of the present invention can be confirmed by conventional methods known to those skilled in the art. If the present invention relates to the absolute configuration of a compound, the absolute configuration can be confirmed by conventional means in the art. For example, in the case of single crystal X-ray diffraction (SXRD), diffraction intensity data is collected from a cultivated single crystal using a Bruker D8 venture diffractometer with CuKα radiation as a light source in φ / ω scanning mode. After collecting relevant data, the absolute configuration can be confirmed by further analyzing the crystal structure by a direct method (Shelxs97).

[0189] The compounds of the present invention can be prepared by various synthetic methods known to those skilled in the art, including the specific embodiments listed below, embodiments in combination with other chemical synthetic methods, and equivalent alternative methods known to those skilled in the art, and preferred embodiments include, but are not limited to, the examples of the present invention.

[0190] The materials and solvents used in the present invention can be obtained commercially.

[0191] Compounds are named using conventional nomenclature in the art or ChemDraw® software; commercially available compounds are named according to the supplier's catalog name.

[0192] In the present invention, compound groups or reagents well known to those skilled in the art can be represented by abbreviations, and the above abbreviations include, but are not limited to, compound groups such as tert-butoxycarbonyl (BOC), benzyl (Bn), p-toluenesulfonyl (Tos), carbobenzyloxy (Cbz), fluorenylmethyloxycarbonyl (Fmoc), tosyl (Ts), allyloxycarbonyl (Alloc), dimethyl sulfoxide (DMSO), dichloromethane (DCM), N,N-dimethyl Formamide (DMF), tetrahydrofuran (THF), trifluoroacetic acid (TFA), N,N'-diisopropylcarbodiimide (DIC), 1-hydroxybenzotriazole (HOBt), benzotriazole-N,N,N',N'-tetramethyluronium-hexafluorophosphate (HBTU), 1-hydroxy-7-azabenzotriazole (HOAT), tetrakis(triphenylphosphine)palladium (Pd(PPh3)4), Fmoc-AEEA-OH TIFF2026503073000169.tif1617020‐(tert-butoxy)‐20‐oxoicosanoic acid TIFF2026503073000170.tif24170N‐Boc‐N'‐Fmoc‐Lys‐OH TIFF2026503073000171.tif2417019‐(bis(benzyloxy)phosphoryl)nonadecanoic acid These include, but are not limited to, conventional reagents such as TIFF2026503073000172.tif39170. DETAILED DESCRIPTION OF THE INVENTION

[0193] The present invention will be described in more detail below with reference to examples, but this is not intended to limit the present invention in any way. Although the present invention is described in detail herein, specific embodiments thereof are also disclosed, and it will be apparent to those skilled in the art that various modifications and improvements can be made to the specific embodiments of the present invention without departing from the spirit and scope of the present invention. The specific synthesis steps described in the present invention further include novel intermediates and methods for synthesizing the polypeptide compound of the present invention or a pharmaceutically acceptable salt thereof. In the specific synthesis steps of the following examples, a person skilled in the art can prepare the polypeptide compound of the present invention or a salt thereof by combining different methods.

[0194] Generally, the polypeptides with a series of modified structures described in this invention are prepared using solid-phase polypeptide synthesis, starting from MBHA resin and employing the Fmoc strategy to condense protected amino acids one by one from the C-terminus to the N-terminus of the peptide sequence (including cycles of condensation, deprotection, and elution, followed by removal of side chain protection to form a lactam ring), followed by cleavage, filtration, concentration, precipitation, filtration, and drying to obtain the crude branched cyclic peptide cleavage product, which is then purified, concentrated, and frozen to obtain the final product.

[0195] Example 1 TIFF2026503073000173.tif42170 The synthesis of peptide resins was carried out according to a conventional solid-phase synthesis process using a solid-phase reaction column equipped with a sintered filter at the bottom for bubbling nitrogen gas during the reaction, and MBHA The peptide backbone was synthesized from the C- to N-terminus by sequential condensation of amino acids using the starting resin, Lys-Lys(Mtt)-OH. After the backbone synthesis was completed, the ε-amino group of Fmoc-Lys(Mtt)-OH at position A-23 was deprotected by removing the -Mtt group. Next, the side chains 1 to 5 ((2-2-oxoethyl)-glycine, AEEA, AEEA, γGlu, and 20-(tert-butoxy)-20-oxoicosanoic acid) were sequentially condensed. Finally, the ε-amino protecting group of Lys at position A-19 and the carboxyl protecting group of (2-2-oxoethyl)-glycine at position 1 were removed. The lactam ring was then formed with the addition of a condensation agent to obtain the target peptide resin.

[0196] The specific steps are as follows: Step 1: Coupling of resin with Fmoc-Rink Linker 1. 10.2 g (5 mmol) of MBHA resin (S = 0.49 mmol / g) was added to a solid-phase reaction column, and 70 mL of DCM was added. The resin was left for 20 min to fully swell, and the DCM was drained. Next, 60 mL of DMF was added while bubbling nitrogen gas to wash the resin. This step was repeated once, and the solvent was drained. 10.8 g (20 mmol, 4.0 eq) of Fmoc-Rink Linker was weighed, dissolved in 40 mL of DMF, and added to the resin. 2.78 g (22 mmol, 4.4 eq) of DIC was added to the reaction column, and 10 mL of DMF was added while bubbling nitrogen gas. After complete dissolution, 2.70 g (20 mmol, 4.0 eq) of HOBt was added, and the reaction was continued while bubbling nitrogen. After reacting at 2.25°C for 2 hours or more, a sample was taken and detected with ninhydrin, which was negative (the resin was colorless or pale yellow), so the reaction was terminated. 3. The reaction solution was removed and washed five times with DMF (300 mL) for 1 minute each time, and the waste liquid was drained until no more liquid flowed out.

[0197] Step 2: Coupling of Fmoc-Ser(tBu)-OH 1. 20% piperidine / DMF (100 mL) was added to the reaction column, and the reaction was allowed to proceed for 10 minutes while bubbling nitrogen gas. The waste liquid was discharged until no more liquid flowed out. 20% piperidine / DMF (100 mL) was added to the reaction column again, and the reaction was allowed to proceed for 5 minutes while bubbling nitrogen gas. A sample was then taken and detected with ninhydrin, which showed that the resin was blue. 2. 7.66 g (4.0 eq) of Fmoc-Ser(tBu)-OH, 2.78 g (4.4 eq) of DIC, and 2.70 g (4.0 eq) of HOBt were weighed and dissolved in 60 mL of DMF. The solution was then added to a reaction column while bubbling nitrogen gas through it. The nitrogen was adjusted so that the resin swelled evenly. After reacting at 3.25°C for 2.0 hours, a sample was taken and detected with ninhydrin, revealing that the resin was colorless and transparent. 4. The reaction solution was removed and washed five times with DMF (300 mL) for 1 minute each time, and the waste liquid was drained until no more liquid flowed out.

[0198] Coupling steps for the remaining amino acids on the backbone Referring to the coupling method and input equivalents of Fmoc-Ser(tBu)-OH in Step 2, the amino acid sequence was sequentially coupled, and the order and the protecting group-containing amino acids used are shown below. TIFF2026503073000174.tif233170

[0199] Step 3: Branch Coupling 1. 300 mL of DMF and 300 mL of DCM were added to the reaction column in sequence, and the resin was washed alternately four times. After the solvent was drained, 300 mL of a 20% hexafluoroisopropanol (HFIP)-DCM solution was added, and the reaction was carried out twice, for 30 minutes each time, while bubbling nitrogen gas. 2. The waste liquid was drained until no more liquid flowed out, and a sample was taken. When detected with ninhydrin, the resin turned blue. 3. 300 mL of DCM and 300 mL of DMF were added successively to wash the resin alternately four times, and the waste liquid was discharged until no more liquid flowed out. 4. Weigh out 7.9 g (4.0 eq) of Fmoc-(2-(allyloxy)-2-oxoethyl)glycine (Fmoc-Ida(OAll)-OH), 2.78 g (4.4 eq) of DIC, and 2.70 g (4.0 eq) of HOBt, dissolve them in 100 mL of DMF, and then add them to a reaction column while bubbling nitrogen gas. Adjust the nitrogen so that the resin swells evenly. After reacting at 5.25°C for 2.0 hours, a sample was taken and detected with ninhydrin, revealing that the resin was colorless and transparent. 6. The reaction solution was removed and washed with DMF (300 mL) five times for 1 minute each time, and the waste liquid was drained until no more liquid flowed out.

[0200] Coupling steps for the remaining branches Referring to the coupling method and input equivalents of Fmoc-Ser(tBu)-OH in Step 2, the compounds shown in the table below were coupled sequentially. TIFF2026503073000175.tif35170

[0201] Step 4: Cyclization 1. 300 mL of DMF and 300 mL of DCM were added to the reaction column in this order to wash the resin alternately four times, and the waste liquid was discharged until no more liquid flowed out. 2. 400 ml of a mixed solvent of DCM, CH3CN, NMP, and DEA in a volume ratio of 3:3:2:2 was added, followed by 0.58 g (0.1 eq) of Pd(PPh3)4. The reaction was carried out for 10 minutes while bubbling nitrogen gas through the mixture, and the waste liquid was discharged until no more liquid flowed out. 3. Repeat the above steps once or twice. 4. A sample was taken and detected with ninhydrin, which revealed that the resin was blue in color. 5. 300 mL of DMF and 300 mL of DCM were added successively, and the resin was washed alternately eight times. 6. 2.78 g (4.4 eq) of DIC and 2.70 g (4.0 eq) of HOBt were dissolved in 150 mL of DMF and added to a reaction column. The reaction was allowed to proceed for 48 hours while bubbling nitrogen gas through the column. After that, a sample was taken and detected with ninhydrin. The resin was found to be colorless. 7. 300 mL of DMF and 300 mL of DCM were added successively, and the resin was washed alternately eight times. 8. 200 mL of MeOH and 300 mL of DCM were added successively, and the resin was washed four times alternately. 9. The resin was taken out and dried under vacuum until the weight no longer decreased, and the weight was measured, resulting in 17.8 g of peptide resin.

[0202] The structural formula of the obtained intermediate (peptide resin) is as follows: Boc‐Tyr(tBu)‐Aib‐Gln(Trt)‐Gly‐Thr(tBu)‐Phe‐Thr(tBu)‐Ser(tBu)‐Asp(OtBu)‐Tyr(tBu)‐Ser(tBu)‐Ile‐a‐MeLeu‐Leu‐Asp(OtBu)‐Lys(Boc)‐Lys 17 -Ala-Gln(Trt)-Aib-Lys 21 ‐Phe‐Ile‐Glu(OtBu)‐Tyr(tBu)‐Leu‐Leu‐Glu(OtBu)‐Gly‐Gly‐Pro‐Ser(tBu)‐Ser(tBu)‐Gly‐Ala‐Pro‐Pro‐Pro‐Ser(tBu)‐Rink Linker ‐MBHA Resin(17,21(Nε(Na‐OC‐(CH2) 18‐COOtBu)‐Glu(ε‐OtBu)‐AEEA‐AEEA)‐(2‐2‐oxoethyl)glycine))

[0203] Step 5: Cleavage of the peptide resin A 250 mL cleavage reagent was prepared from trifluoroacetic acid (TFA), purified water (HO), triisopropylsilane (TIS), 1,2-ethanedithiol (EDT), and phenol (ArOH) in a volume ratio of TFA:HO:EDT:TIS:ArOH = 86.5:5:2.5:1:5 and pre-cooled to 10±3°C. The resin was slowly added to the cleavage reagent while stirring until the reaction temperature stabilized. The reaction was allowed to proceed for 4 hours with stirring while controlling the temperature at 18±3°C. The cleavage solution was filtered, concentrated to a viscous solution, and precipitated with methyl tert-butyl ether in an amount 12-15 times the volume of the concentrate. The precipitate was filtered, washed, and dried under reduced pressure at room temperature to yield 7.9 g of crude cyclic peptide.

[0204] Step 6: Chromatographic purification 7.9 g of the crude cyclic peptide was dissolved in 10% acetonitrile and 10% acetic acid in water and purified by high-performance liquid chromatography using a C18 silica gel matrix packing. Fractions with a purity of >90% were collected and combined. The purification chromatography system is shown in the table below. TIFF2026503073000176.tif40170

[0205] Step 7: Concentration and freeze-drying The fractions obtained in the above steps were concentrated to remove acetonitrile, filtered through a 0.22 μm Millipore filter membrane, loaded into a vial freeze-dryer, and freeze-dried to obtain 0.93 g of the final target polypeptide product (purity: 94.97%). The molecular weight of the polypeptide was confirmed by ESI-MS, with the calculated value [M+4H] / 4 being 1258.7 and the detected value being 1258.7.

[0206] Example 2 The polypeptide shown in Example 2 was obtained with reference to the synthesis of the polypeptide in Example 1. The molecular weight of the polypeptide was confirmed by ESI-MS, and the calculated value [M+4H] / 4 was 1249.7, and the detected value was 1249.4.

[0207] Example 3 TIFF2026503073000178.tif64170Step 1: Coupling of resin with Fmoc-Rink Linker 1. 10.2 g (5 mmol) of MBHA resin (S = 0.49 mmol / g) was added to a solid-phase reaction column, and 70 mL of DCM was added. The resin was left for 20 min to fully swell, and the DCM was drained. Next, 60 mL of DMF was added while bubbling nitrogen gas to wash the resin. This step was repeated once, and the solvent was drained. 10.8 g (20 mmol, 4.0 eq) of Fmoc-Rink Linker was weighed, dissolved in 40 mL of DMF, and added to the resin. 2.78 g (22 mmol, 4.4 eq) of DIC was added to the reaction column, and 10 mL of DMF was added while bubbling nitrogen gas. After complete dissolution, 2.70 g (20 mmol, 4.0 eq) of HOBt was added, and the reaction was continued while bubbling nitrogen. After reacting at 2.25°C for 2 hours or more, a sample was taken and detected with ninhydrin, which was negative (the resin was colorless or pale yellow), so the reaction was terminated. 3. The reaction solution was removed and washed five times with DMF (300 mL) for 1 minute each time, and the waste liquid was drained until no more liquid flowed out.

[0208] Step 2: Coupling of Fmoc-Ser(tBu)-OH 1. 20% piperidine / DMF (100 mL) was added to the reaction column, and the reaction was allowed to proceed for 10 minutes while bubbling nitrogen gas. The waste liquid was discharged until no more liquid flowed out. 20% piperidine / DMF (100 mL) was added to the reaction column again, and the reaction was allowed to proceed for 5 minutes while bubbling nitrogen gas. A sample was then taken and detected with ninhydrin, which showed that the resin was blue. 2. 7.66 g (4.0 eq) of Fmoc-Ser(tBu)-OH, 2.78 g (4.4 eq) of DIC, and 2.70 g (4.0 eq) of HOBt were weighed and dissolved in 60 mL of DMF. The solution was then added to a reaction column while bubbling nitrogen gas through it. The nitrogen was adjusted so that the resin swelled evenly. After reacting at 3.25°C for 2.0 hours, a sample was taken and detected with ninhydrin, revealing that the resin was colorless and transparent. 4. The reaction solution was removed and washed five times with DMF (300 mL) for 1 minute each time, and the waste liquid was drained until no more liquid flowed out.

[0209] Coupling steps for the remaining amino acids on the backbone Referring to the coupling method and input equivalents of Fmoc-Ser(tBu)-OH in Step 2, the amino acid sequence was sequentially coupled, and the order and the protecting group-containing amino acids used are shown below. TIFF2026503073000179.tif233170

[0210] Step 3: Branch Coupling 1. 300 mL of DMF and 300 mL of DCM were added to the reaction column in sequence, and the resin was washed alternately four times. After the solvent was drained, 300 mL of a 20% hexafluoroisopropanol (HFIP)-DCM solution was added, and the reaction was carried out twice, for 30 minutes each time, while bubbling nitrogen gas. 2. The waste liquid was drained until no more liquid flowed out, and a sample was taken. When detected with ninhydrin, the resin turned blue. 3. 300 mL of DCM and 300 mL of DMF were added successively to wash the resin alternately four times, and the waste liquid was discharged until no more liquid flowed out. 4. 9.05 g (4.0 eq) of Alloc-Lys(Fmoc)-OH, 2.78 g (4.4 eq) of DIC, and 2.70 g (4.0 eq) of HOBt were weighed and dissolved in 100 mL of DMF. The solution was then added to a reaction column while bubbling nitrogen gas through it. The nitrogen was adjusted so that the resin swelled evenly. After reacting at 5.25°C for 2.0 hours, a sample was taken and detected with ninhydrin, revealing that the resin was colorless and transparent. 6. The reaction solution was removed and washed with DMF (300 mL) five times for 1 minute each time, and the waste liquid was drained until no more liquid flowed out.

[0211] Coupling steps for the remaining branches Referring to the coupling method and input equivalents of Fmoc-Ser(tBu)-OH in Step 2, the compounds shown in the table below were coupled sequentially. TIFF2026503073000180.tif29170

[0212] Step 4: Cyclization 1. 300 mL of DMF and 300 mL of DCM were added to the reaction column in this order to wash the resin alternately four times, and the waste liquid was discharged until no more liquid flowed out. 2. 400 mL of a mixed solvent of DCM, CH3CN, NMP, and DEA was prepared in a volume ratio of 3:3:2:2 and placed in a reaction column. 0.58 g (0.1 eq) of Pd(PPh3)4 was added, and the reaction was carried out for 10 minutes while bubbling nitrogen gas through the column. The waste liquid was discharged until no more liquid flowed out. 3. Repeat the above steps once or twice. 4. A sample was taken and detected with ninhydrin, which revealed that the resin was blue in color. 5. 300 mL of DMF and 300 mL of DCM were added successively, and the resin was washed alternately eight times. 6. 2.78 g (4.4 eq) of DIC and 2.70 g (4.0 eq) of HOBt were dissolved in 150 mL of DMF and placed in a reaction column. The reaction was carried out for 48 hours while bubbling nitrogen gas through the column. A sample was taken and detected with ninhydrin, revealing that the resin was colorless. 7. 300 mL of DMF and 300 mL of DCM were added successively, and the resin was washed alternately eight times. 8. 200 mL of MeOH and 300 mL of DCM were added successively, and the resin was washed four times alternately. 9. The resin was taken out and dried under vacuum until the weight no longer decreased, and the weight was measured, resulting in 19.2 g of peptide resin.

[0213] The structural formula of the obtained intermediate (peptide resin) is as follows: Boc‐Tyr(tBu)‐Aib‐Gln(Trt)‐Gly‐Thr(tBu)‐Phe‐Thr(tBu)‐Ser(tBu)‐Asp(OtBu)‐Tyr(tBu)‐Ser(tBu )‐Ile‐a‐MeLeu‐Leu‐Asp(OtBu)‐Lys(Boc)‐Lys(Boc)‐Ala‐Gln(Trt)‐Aib‐Ala‐Phe‐Ile‐Glu(OtBu)‐Lys 25 -Leu-Leu-Glu 28 ‐Gly‐Gly‐Pro‐Ser(tBu)‐Ser(tBu)‐Gly‐Ala‐Pro‐Pro‐Pro‐Ser(tBu)‐Rink Linker‐MBHA Resin(25,28(Nε(COOH‐(CH2) 18 ‐COOtBu)‐Glu(ε‐OtBu)‐AEEA)‐(2‐2‐oxoethyl)glycine))

[0214] Step 5: Cleavage of the peptide resin A 250 mL cleavage reagent was prepared from trifluoroacetic acid (TFA), purified water (HO), triisopropylsilane (TIS), 1,2-ethanedithiol (EDT), and phenol (ArOH) in a volume ratio of TFA:HO:EDT:TIS:ArOH = 86.5:5:2.5:1:5 and precooled to 10 ± 3 °C. The resin was slowly added to the cleavage reagent while stirring until the reaction temperature stabilized. The reaction was allowed to proceed for 4 h while maintaining the temperature at 18 ± 3 °C. The cleavage solution was filtered, concentrated to a viscous solution, and precipitated with 12–15 times the volume of the concentrate, methyl tert-butyl ether. The precipitate was filtered, washed, and dried under reduced pressure at room temperature to yield 8.2 g of crude cyclic peptide.

[0215] Step 6: Chromatographic purification 8.2 g of the crude cyclic peptide was dissolved in 10% acetonitrile and 10% acetic acid in water and purified by high-performance liquid chromatography using a C18 silica gel matrix packing. Fractions with a purity of >90% were collected and combined. The purification chromatography system is shown in the table below. TIFF2026503073000181.tif40170

[0216] Step 7: Concentration and freeze-drying The fractions obtained in the above steps were concentrated to remove acetonitrile, filtered through a 0.22 μm Millipore filter membrane, loaded into a vial freeze-dryer, and freeze-dried to obtain 1.01 g of the final product shown in Example 3 (purity: 94.97%). The molecular weight of the polypeptide was confirmed by ESI-MS, with the calculated value [M+4H] / 4 being 1202.6 and the detected value being 1202.6.

[0217] Example 4 The polypeptide shown in Example 4 was obtained with reference to the synthesis of the polypeptide in Example 1. The molecular weight of the polypeptide was confirmed by ESI-MS, and the calculated value [M+4H] / 4 was 1277.7, and the detected value was 1277.6.

[0218] Example 5 The polypeptide shown in Example 5 was obtained with reference to the synthesis of the polypeptide in Example 1. The molecular weight of the polypeptide was confirmed by ESI-MS, and the calculated value [M+4H] / 4 was 1277.7, and the detected value was 1277.5.

[0219] Example 6 The polypeptide shown in Example 6 was obtained with reference to the synthesis of the polypeptide in Example 1. The molecular weight of the polypeptide was confirmed by ESI-MS, and the calculated value [M+4H] / 4 was 1122.4, and the detected value was 1122.5.

[0220] Example 7 TIFF2026503073000185.tif50170 Referring to the synthesis of the polypeptide in Example 1, the polypeptide shown in Example 7 was obtained, in which the protecting groups of amino acids used for branched chain coupling were, in order, Fmoc-Ida(OAll)-OH, N-Boc-N'-Fmoc-Lys-OH, N-Boc-N'-Fmoc-Lys-OH, Fmoc-Glu-OtBu, and 20-(tert-butoxy)-20-oxoicosanoic acid. The molecular weight of the polypeptide was confirmed by ESI-MS, with a calculated value of [M+4H] / 4 of 1250.2 and a detected value of 1250.2.

[0221] Example 8 The polypeptide shown in Example 8 was obtained by referring to the synthesis of the polypeptide in Example 1, where the protecting group amino acids used for branched chain coupling were Fmoc-Glu(OAll)-OH, Fmoc-AEEA-OH, Fmoc-Glu-OtBu, and 20-(tert-butoxy)-20-oxoicosanoic acid, respectively. The molecular weight of the polypeptide was confirmed by ESI-MS, with a calculated value of [M+4H] / 4 of 1225.9 and a detected value of 1226.0.

[0222] Example 9 The polypeptide shown in Example 9 was obtained with reference to the synthesis of the polypeptide in Example 1. The molecular weight of the polypeptide was confirmed by ESI-MS, and the calculated value [M+4H] / 4 was 1218.4, and the detected value was 1218.3.

[0223] Example 10 The polypeptide shown in Example 10 was obtained by referring to the synthesis of the polypeptide in Example 3. The molecular weight of the polypeptide was confirmed by ESI-MS, and the calculated value [M+4H] / 4 was 1225.9, and the detected value was 1224.2.

[0224] Example 11 The polypeptide shown in Example 11 was obtained with reference to the synthesis of the polypeptide in Example 1. The molecular weight of the polypeptide was confirmed by ESI-MS, and the calculated value [M+4H] / 4 was 1244.2, and the detected value was 1242.7.

[0225] Example 12 TIFF2026503073000190.tif50170 Referring to the synthesis of the polypeptide in Example 1, the polypeptide shown in Example 12 was obtained, in which the protecting group amino acids used for branched chain coupling were, in order, Fmoc-Glu-OAll, Fmoc-AEEA-OH, Fmoc-AEEA-OH, Fmoc-Glu-OtBu, and 20-(tert-butoxy)-20-oxoicosanoic acid. The molecular weight of the polypeptide was confirmed by ESI-MS, with a calculated value of [M+4H] / 4 of 1262.2 and a detected value of 1262.2.

[0226] Example 13 The polypeptide shown in Example 13 was obtained with reference to the synthesis of the polypeptide in Example 1. The molecular weight of the polypeptide was confirmed by ESI-MS, and the calculated value [M+4H] / 4 was 1244.2, and the detected value was 1244.2.

[0227] Example 14 The polypeptide shown in Example 14 was obtained with reference to the synthesis of the polypeptide in Example 1. The molecular weight of the polypeptide was confirmed by ESI-MS, and the calculated value [M+4H] / 4 was 1258.5, and the detected value was 1258.4.

[0228] Example 15 The polypeptide shown in Example 15 was obtained with reference to the synthesis of the polypeptide in Example 1. The molecular weight of the polypeptide was confirmed by ESI-MS, and the calculated value [M+4H] / 4 was 1258.7, and the detected value was 1258.6.

[0229] Example 16 The polypeptide shown in Example 16 was obtained with reference to the synthesis of the polypeptide in Example 1. The molecular weight of the polypeptide was confirmed by ESI-MS, and the calculated value [M+4H] / 4 was 1258.7, and the detected value was 1258.6.

[0230] Example 17 The polypeptide shown in Example 17 was obtained with reference to the synthesis of the polypeptide in Example 1. The molecular weight of the polypeptide was confirmed by ESI-MS, and the calculated value [M+4H] / 4 was 1255.2, and the detected value was 1255.1.

[0231] Example 18 TIFF2026503073000196.tif49170 Referring to the synthesis of the polypeptide in Example 1, the polypeptide shown in Example 18 was obtained, in which the protecting groups of amino acids used for branched chain coupling were, in order, Fmoc-Ida(OAll)-OH, N-Boc-N'-Fmoc-Lys-OH, N-Boc-N'-Fmoc-Lys-OH, Fmoc-Glu-OtBu, and 20-(tert-butoxy)-20-oxoicosanoic acid. The molecular weight of the polypeptide was confirmed by ESI-MS, with a calculated value of [M+4H] / 4 of 1235.7 and a detected value of 1234.7.

[0232] Example 19 TIFF2026503073000197.tif50170 Referring to the synthesis of the polypeptide in Example 1, the polypeptide shown in Example 19 was obtained, in which the protecting groups of amino acids used for branched chain coupling were, in order, Fmoc-Ida(OAll)-OH, N-Boc-N'-Fmoc-Lys-OH, N-Boc-N'-Fmoc-Lys-OH, Fmoc-Glu-OtBu, and 20-(tert-butoxy)-20-oxoicosanoic acid. The molecular weight of the polypeptide was confirmed by ESI-MS, with a calculated value of [M+4H] / 4 of 1250.0 and a detected value of 1249.0.

[0233] Example 20 TIFF2026503073000198.tif47170 Referring to the synthesis of the polypeptide in Example 1, the polypeptide shown in Example 20 was obtained, in which the protecting groups of amino acids used for branched chain coupling were, in order, Fmoc-Ida(OAll)-OH, N-Boc-N'-Fmoc-Lys-OH, N-Boc-N'-Fmoc-Lys-OH, Fmoc-Glu-OtBu, and 20-(tert-butoxy)-20-oxoicosanoic acid. The molecular weight of the polypeptide was confirmed by ESI-MS, with a calculated value of [M+4H] / 4 of 1250.2 and a detected value of 1249.2.

[0234] Example 21 TIFF2026503073000199.tif63170 The synthesis of peptide resins was carried out according to the conventional solid-phase synthesis process using a solid-phase reaction column equipped with a sintered filter at the bottom for bubbling nitrogen gas during the reaction. MBHA resin was used as the starting resin, and conventional Fmoc-protected amino acids were added. The condensation agent used was a DIC / HOBt system using DMF as the main reaction solvent and 20% PIP-DMF solution as the Fmoc removal solvent. The peptide backbone was synthesized from the C-terminus to the N-terminus by sequentially condensing the amino acids. After the backbone synthesis was completed, the ε-amino group of Fmoc-Lys(Mtt)-OH at position A-26 was deprotected by removing the -Mtt. Next, side chains 1 to 4 ((2-2-oxoethyl)-glycine, AEEA, γ) were added. Glu, 20-(tert-butoxy)-20-oxoicosanoic acid) were sequentially condensed, and then the ε-amino protecting group of Lys at position A-23 and the carboxyl protecting group of (2-2-oxoethyl)-glycine at position 1 of the side chain were removed. After that, a condensing agent was added to form a lactam ring, and the target peptide resin was obtained.

[0235] The specific steps are as follows: Step 1: Resin activation and deprotection 1. 15 g (5.1 mmol) of MBHA resin (S = 0.34 mmol / g) was added to a solid-phase reaction column, and 225 mL of DCM was added. The resin was left for 20 min to completely swell. The DCM was then drained. Next, 150 mL of DMF was added while bubbling nitrogen gas to wash the resin. This step was repeated once, and the solvent was drained. 20% piperidine / DMF (150 mL) was added to the reaction column, and the reaction was continued for 5 min while bubbling nitrogen gas. The waste solution was drained until no more liquid flowed out. 20% piperidine / DMF (150 mL) was added again to the reaction column, and the reaction was continued for 15 min while bubbling nitrogen gas. A sample was taken, and when detected with ninhydrin, the resin turned gray-red. The reaction solution was removed and washed with 150 mL of DMF (7 times, adjusting the pH to 7), for 1 min each time. The waste solution was drained until no more liquid flowed out.

[0236] Step 2: Coupling of Fmoc-Ser(tBu)-OH 1. 5.75 g (3.0 eq) of Fmoc-Ser(tBu)-OH, 2.52 g (4.0 eq) of DIC, and 2.03 g (3.0 eq) of HOBt were weighed and dissolved in 80 mL of DMF. The solution was then added to a reaction column while bubbling nitrogen gas through it. The nitrogen was adjusted so that the resin swelled evenly. After reacting at 2.25°C for 2.0 hours, a sample was taken and detected with ninhydrin, revealing that the resin was colorless and transparent. 3. The reaction solution was removed and washed five times with DMF (150 mL) for 1 minute each time, and the waste liquid was drained until no more liquid flowed out.

[0237] Coupling steps for the remaining amino acids on the backbone Referring to the coupling method and input equivalents of Fmoc-Ser(tBu)-OH in Step 2, the amino acid sequence was sequentially coupled, and the order and the protecting group-containing amino acids used are shown below. TIFF2026503073000200.tif64170

[0238] The AA-11 peptide was obtained.

[0239] Step 3: Deprotection of the AA-11 peptide 1. The synthesized AA-11 peptide was added with DMF (80 mL) and activated for 10 minutes. The liquid was then discharged until no more liquid flowed out. 20% piperidine / DMF (80 mL) was added to the reaction column and reacted for 10 minutes while bubbling nitrogen gas. The waste liquid was then discharged until no more liquid flowed out. 20% piperidine / DMF (80 mL) was added to the reaction column again and the reaction continued for 10 minutes while bubbling nitrogen gas. A sample was taken and detected with ninhydrin. The resin was found to be dark yellow. The reaction solution was removed and washed with DMF (100 mL) 8 times, each time for 1 minute, to adjust the pH to about 7. The waste liquid was then discharged until no more liquid flowed out.

[0240] Step 4: Coupling of Fmoc-Glu(OtBu)-OH 1. 3.04 g (3.0 eq) of Fmoc-Glu(OtBu)-OH, 1.20 g (4.0 eq) of DIC, and 0.965 g (3.0 eq) of HOBt were weighed and dissolved in 50 mL of DMF. The solution was then added to a reaction column while bubbling nitrogen gas through it. The nitrogen was adjusted so that the resin swelled evenly. After reacting at 2.25°C for 3.0 hours, a sample was taken and detected with ninhydrin, revealing that the resin was colorless and transparent. 3. The reaction solution was removed and washed five times with DMF (80 mL) for 1 minute each time, and the waste liquid was drained until no more liquid flowed out.

[0241] Coupling steps for the remaining amino acids on the backbone The amino acid sequence was sequentially linked by referring to the coupling method and order of Fmoc-Glu(OtBu)-OH in Step 4, and the order and the protecting group-containing amino acids used are shown below. TIFF2026503073000201.tif165170

[0242] Step 5: Branched Chain Coupling 1. 300 mL of DCM was added to the reaction column to wash the resin four times. After the solvent was drained, 80 mL of a 20% hexafluoroisopropanol (HFIP)-DCM solution was added, and the reaction was carried out five times, for 30 minutes each time, while bubbling nitrogen gas. 2. The waste liquid was drained until no more liquid flowed out, and a sample was taken. When detected with ninhydrin, the resin appeared gray-green. 3. 80 mL of DCM and 80 mL of DMF were added successively to wash the resin alternately four times, and the waste liquid was discharged until no more liquid flowed out. 4. Weigh out 4.7 g (5.0 eq) of Fmoc-(2-(allyloxy)-2-oxoethyl)glycine (Fmoc-Ida(OAll)-OH), 1.67 g (6.0 eq) of DIC, and 1.49 g (5.0 eq) of HOBt, dissolve them in 100 mL of DMF, and then add them to a reaction column while bubbling nitrogen gas. Adjust the nitrogen so that the resin swells evenly. After reacting at 5.25°C for 5.0 hours, a sample was taken and detected with ninhydrin, revealing that the resin was colorless and transparent. 6. The reaction solution was removed and washed five times with DMF (80 mL) for 1 minute each time, and the waste liquid was drained until no more liquid flowed out.

[0243] Coupling steps for the remaining branches Referring to the coupling method and input equivalents of Fmoc-Glu(OtBu)-OH in Step 4, the compounds shown in the table below were coupled sequentially. TIFF2026503073000202.tif29170

[0244] Step 6: Cyclization 1. 80 mL of DMF and 80 mL of DCM were added to the reaction column in this order to wash the resin alternately four times, and the waste liquid was discharged until no more liquid flowed out. 2. 300 mL of a mixed solvent of DCM, CH3CN, NMP, and DEA was prepared in a volume ratio of 3:3:2:2 and placed in a reaction column. 0.74 g (0.27 eq) of Pd(PPh3)4 was added, and the reaction was carried out for 10 minutes while bubbling nitrogen gas through the column. The waste liquid was discharged until no more liquid flowed out. 3. A sample was taken and tested with ninhydrin, which revealed that the resin was purplish yellow. 4. 80 mL of DMF and 80 mL of DCM were added successively, and the resin was washed alternately eight times. 5. 1.67 g (6.0 eq) of DIC and 1.49 g (5.0 eq) of HOBt were dissolved in 80 mL of DMF and placed in a reaction column. The reaction was carried out for 22 hours while bubbling nitrogen gas through the column. A sample was taken and detected with ninhydrin, revealing that the resin was colorless. 6. 80 mL of DMF and 80 mL of DCM were added successively, and the resin was washed alternately eight times. 7. 80 mL of MeOH and 80 mL of DCM were added successively, and the resin was washed four times alternately. 8. The resin was taken out and dried under vacuum until the weight no longer decreased, and the weight was measured, resulting in 19.3 g of peptide resin.

[0245] The structural formula of the obtained intermediate (peptide resin) is as follows: Boc‐Tyr(tBu)‐Aib‐Gln(Trt)‐Gly‐Thr(tBu)‐Phe‐Thr(tBu)‐Ser(tBu)‐Asp(OtBu)‐Tyr(tBu)‐Ser(tBu)‐Ile‐a‐MeLeu‐Lys 14 -Asp(OtBu)-Lys(Boc)-Lys 17 ‐Ala‐Gln(Trt)‐Aib‐Ala‐Phe‐Ile‐Glu(OtBu)‐Tyr(tBu)‐Leu‐Leu‐Glu(OtBu)‐Gly‐Gly‐Pro‐Ser(tBu)‐Ser(tBu)‐Gly‐Ala‐Pro‐Pro‐Pro‐Ser(tBu)‐Rink Linker ‐MBHA Resin(14,17(Nε(HOOC‐(CH2) 18 ‐COOtBu)‐Glu(ε‐OtBu)‐AEEA)‐(2‐2‐oxoethyl)glycine))

[0246] Step 7: Cleavage of the peptide resin A 289 mL cleavage reagent was prepared using trifluoroacetic acid (TFA), purified water (HO), triisopropylsilane (TIS), 3-(tritylthio)propionic acid (Mpa(Trt)-OH, MRP), and phenol (ArOH) in a volume ratio of TFA:HO:Mpa(Trt)-OH:TIS:ArOH = 82.5:2.5:5:5:5 and precooled to 10 ± 3 °C. The resin was slowly added to the cleavage reagent while stirring until the reaction temperature stabilized. The reaction was allowed to proceed for 4 h while maintaining the temperature at 18 ± 3 °C. The cleavage solution was filtered, concentrated to a viscous solution, and precipitated with 12–15 times the volume of the concentrate, methyl tert-butyl ether. The precipitate was filtered, washed, and dried under reduced pressure at room temperature to yield 7.5 g of crude cyclic peptide.

[0247] Step 8. Chromatographic purification 2.1 g of the crude cyclic peptide was dissolved in 5% acetonitrile and 2% aqueous ammonia, and purified by high-performance liquid chromatography using a C8 silica gel matrix packing. Fractions with a purity of >90% were collected and combined. The purification chromatography system is shown in the table below. TIFF2026503073000203.tif40170

[0248] Step 9. Concentration and freeze-drying The fractions obtained in the above steps were concentrated to remove acetonitrile, filtered through a 0.22 μm Millipore filter membrane, loaded into a vial freeze-dryer, and freeze-dried to obtain 0.133 g of the final product of the target polypeptide (purity: 94.2%). The molecular weight of the polypeptide was confirmed by ESI-MS, and the calculated value [M+4H] / 4 was 1211.9, and the detected value was 1210.9.

[0249] Example 22 TIFF2026503073000204.tif46170 Referring to the synthesis of the polypeptide in Example 1, the polypeptide shown in Example 22 was obtained, in which the protecting groups of amino acids used for branched chain coupling were, in order, Fmoc-Ida(OAll)-OH, N-Boc-N'-Fmoc-Lys-OH, N-Boc-N'-Fmoc-Lys-OH, Fmoc-Glu-OtBu, and 20-(tert-butoxy)-20-oxoicosanoic acid. The molecular weight of the polypeptide was confirmed by ESI-MS, with a calculated value of [M+4H] / 4 of 1246.2 and a detected value of 1245.1.

[0250] Example 23 TIFF2026503073000205.tif47170 Referring to the synthesis of the polypeptide in Example 1, the polypeptide shown in Example 23 was obtained, in which the protecting groups of amino acids used for branched chain coupling were, in order, Fmoc-Ida(OAll)-OH, N-Boc-N'-Fmoc-Lys-OH, N-Boc-N'-Fmoc-Lys-OH, Fmoc-Glu-OtBu, and 20-(tert-butoxy)-20-oxoicosanoic acid. The molecular weight of the polypeptide was confirmed by ESI-MS, with a calculated value of [M+4H] / 4 of 1246.2 and a detected value of 1245.2.

[0251] Example 24 TIFF2026503073000206.tif46170 Referring to the synthesis of the polypeptide in Example 1, the polypeptide shown in Example 24 was obtained, in which the protecting groups of amino acids used for branched chain coupling were, in order, Fmoc-Ida(OAll)-OH, N-Boc-N'-Fmoc-Lys-OH, N-Boc-N'-Fmoc-Lys-OH, Fmoc-Glu-OtBu, and 20-(tert-butoxy)-20-oxoicosanoic acid. The molecular weight of the polypeptide was confirmed by ESI-MS, with a calculated value of [M+4H] / 4 of 1242.7 and a detected value of 1241.6.

[0252] Example 25 TIFF2026503073000207.tif59170 Referring to the synthesis of the polypeptide in Example 1, the polypeptide shown in Example 25 was obtained, in which the protecting groups of amino acids used for branched chain coupling were, in order, Fmoc-Ida(OAll)-OH, N-Boc-N'-Fmoc-Lys-OH, N-Boc-N'-Fmoc-Lys-OH, Fmoc-Glu-OtBu, and 20-(tert-butoxy)-20-oxoicosanoic acid. The molecular weight of the polypeptide was confirmed by ESI-MS, with a calculated value of [M+4H] / 4 of 1235.4 and a detected value of 1234.3.

[0253] Example 26 TIFF2026503073000208.tif46170 Referring to the synthesis of the polypeptide in Example 1, the polypeptide shown in Example 26 was obtained, in which the protecting groups of amino acids used for branched chain coupling were, in order, Fmoc-Ida(OAll)-OH, N-Boc-N'-Fmoc-Lys-OH, N-Boc-N'-Fmoc-Lys-OH, Fmoc-Glu-OtBu, and 20-(tert-butoxy)-20-oxoicosanoic acid. The molecular weight of the polypeptide was confirmed by ESI-MS, with a calculated value of [M+4H] / 4 of 1246.0 and a detected value of 1250.0.

[0254] Example 27 TIFF2026503073000209.tif46170 Referring to the synthesis of the polypeptide in Example 1, the polypeptide shown in Example 27 was obtained, in which the protecting groups of amino acids used for branched chain coupling were, in order, Fmoc-Ida(OAll)-OH, N-Boc-N'-Fmoc-Lys-OH, N-Boc-N'-Fmoc-Lys-OH, Fmoc-Glu-OtBu, and 20-(tert-butoxy)-20-oxoicosanoic acid. The molecular weight of the polypeptide was confirmed by ESI-MS, with a calculated value of [M+4H] / 4 of 1235.7 and a detected value of 1234.6.

[0255] Example 28 TIFF2026503073000210.tif48170 Referring to the synthesis of the polypeptide in Example 1, the polypeptide shown in Example 28 was obtained, in which the protecting groups of amino acids used for branched chain coupling were, in order, Fmoc-Ida(OAll)-OH, N-Boc-N'-Fmoc-Lys-OH, N-Boc-N'-Fmoc-Lys-OH, Fmoc-Glu-OtBu, and 20-(tert-butoxy)-20-oxoicosanoic acid. The molecular weight of the polypeptide was confirmed by ESI-MS, with a calculated value of [M+4H] / 4 of 1235.7 and a detected value of 1238.6.

[0256] Example 29 TIFF2026503073000211.tif45170 Referring to the synthesis of the polypeptide in Example 1, the polypeptide shown in Example 29 was obtained, in which the protecting groups of amino acids used for branched chain coupling were, in order, Fmoc-Ida(OAll)-OH, N-Boc-N'-Fmoc-Lys-OH, N-Boc-N'-Fmoc-Lys-OH, Fmoc-Glu-OtBu, and 20-(tert-butoxy)-20-oxoicosanoic acid. The molecular weight of the polypeptide was confirmed by ESI-MS, with a calculated value of [M+4H] / 4 of 1242.5 and a detected value of 1241.5.

[0257] Example 30 TIFF2026503073000212.tif46170 Referring to the synthesis of the polypeptide in Example 1, the polypeptide shown in Example 30 was obtained, in which the protecting groups of amino acids used for branched chain coupling were, in order, Fmoc-Ida(OAll)-OH, N-Boc-N'-Fmoc-Lys-OH, N-Boc-N'-Fmoc-Lys-OH, Fmoc-Glu-OtBu, and 20-(tert-butoxy)-20-oxoicosanoic acid. The molecular weight of the polypeptide was confirmed by ESI-MS, with a calculated value of [M+4H] / 4 of 1242.5 and a detected value of 1241.6.

[0258] Example 31 TIFF2026503073000213.tif46170 Referring to the synthesis of the polypeptide in Example 1, the polypeptide shown in Example 31 was obtained, in which the protecting groups of amino acids used for branched chain coupling were, in order, Fmoc-Ida(OAll)-OH, N-Boc-N'-Fmoc-Lys-OH, N-Boc-N'-Fmoc-Lys-OH, Fmoc-Glu-OtBu, and 20-(tert-butoxy)-20-oxoicosanoic acid. The molecular weight of the polypeptide was confirmed by ESI-MS, with a calculated value of [M+4H] / 4 of 1246.0 and a detected value of 1244.9.

[0259] Example 32 The polypeptide shown in Example 32 was obtained by referring to the synthesis of the polypeptide in Example 1. The molecular weight of the polypeptide was confirmed by ESI-MS, and the calculated value [M+4H] / 4 was 1218.2, and the detected value was 1217.4.

[0260] Example 33 TIFF2026503073000215.tif46170 Referring to the synthesis of the polypeptide in Example 1, the polypeptide shown in Example 33 was obtained, in which the protecting groups of amino acids used for branched chain coupling were, in order, Fmoc-Ida(OAll)-OH, N-Boc-N'-Fmoc-Lys-OH, N-Boc-N'-Fmoc-Lys-OH, Fmoc-Glu-OtBu, and 20-(tert-butoxy)-20-oxoicosanoic acid. The molecular weight of the polypeptide was confirmed by ESI-MS, with a calculated value of [M+4H] / 4 of 1246.0 and a detected value of 1245.9.

[0261] Example 34 The polypeptide shown in Example 34 was obtained by referring to the synthesis of the polypeptide in Example 1. The molecular weight of the polypeptide was confirmed by ESI-MS, and the calculated value [M+4H] / 4 was 1218.2, and the detected value was 1218.1.

[0262] Example 35 TIFF2026503073000217.tif46170 Referring to the synthesis of the polypeptide in Example 1, the polypeptide shown in Example 35 was obtained, in which the protecting groups of amino acids used for branched chain coupling were, in order, Fmoc-Ida(OAll)-OH, N-Boc-N'-Fmoc-Lys-OH, N-Boc-N'-Fmoc-Lys-OH, Fmoc-Glu-OtBu, and 20-(tert-butoxy)-20-oxoicosanoic acid. The molecular weight of the polypeptide was confirmed by ESI-MS, with a calculated value of [M+4H] / 4 of 1250.0 and a detected value of 1250.0.

[0263] Example 36 The polypeptide shown in Example 36 was obtained with reference to the synthesis of the polypeptide in Example 1. The molecular weight of the polypeptide was confirmed by ESI-MS, and the calculated value [M+4H] / 4 was 1222.2, and the detected value was 1222.1.

[0264] Example 37 The polypeptide shown in Example 37 was obtained by referring to the synthesis of the polypeptide in Example 1. The molecular weight of the polypeptide was confirmed by ESI-MS, and the calculated value [M+4H] / 4 was 1226.4, and the detected value was 1226.3.

[0265] Example 38 TIFF2026503073000220.tif63170 The same synthesis process as in Example 21 above was used. MBHA Resin was used as the starting resin. Conventional Fmoc-protected amino acids were added. The condensation agent used was a DIC / HOBt system using DMF as the main reaction solvent and 20% PIP-DMF solution as the Fmoc removal solvent. The peptide backbone was synthesized from the C-terminus to the N-terminus by sequentially condensing the amino acids. After the backbone synthesis was completed, the peptide was deprotected by removing the -Mtt from the ε-amino group of Fmoc-Lys(Mtt)-OH at position A-26. Next, side chains 1 to 4 ((2-2-oxoethyl)-glycine, AEEA, γ) were added. Glu, 20-(tert-butoxy)-20-oxoicosanoic acid) were sequentially condensed, and then the ε-amino protecting group of Lys at position A-23 and the carboxyl protecting group of (2-2-oxoethyl)-glycine at position 1 of the side chain were removed. After that, a condensing agent was added to form a lactam ring, and the target peptide resin was obtained.

[0266] The specific steps are as follows: Step 1: Resin activation and deprotection 1. 15 g (5.1 mmol) of MBHA resin (S = 0.34 mmol / g) was added to a solid-phase reaction column, and 225 mL of DCM was added. The resin was left for 20 min to completely swell. The DCM was then drained. Next, 150 mL of DMF was added while bubbling nitrogen gas to wash the resin. This step was repeated once, and the solvent was drained. 20% piperidine / DMF (150 mL) was added to the reaction column, and the reaction was continued for 10 min while bubbling nitrogen gas. The waste solution was drained until no more liquid flowed out. 20% piperidine / DMF (150 mL) was added again to the reaction column, and the reaction was continued for 10 min while bubbling nitrogen gas. A sample was taken, and when detected with ninhydrin, the resin turned gray-red. The reaction solution was then withdrawn and washed with 150 mL of DMF (8 times, 1 min each time, adjusting the pH to 7). The waste solution was drained until no more liquid flowed out.

[0267] Step 2: Coupling of Fmoc-Ser(tBu)-OH 1. 5.86 g (3.0 eq) of Fmoc-Ser(tBu)-OH, 2.57 g (4.0 eq) of DIC, and 2.07 g (3.0 eq) of HOBt were weighed and dissolved in 80 mL of DMF. The solution was then added to a reaction column while bubbling nitrogen gas through it. The nitrogen was adjusted so that the resin swelled evenly. After reacting at 2.25°C for 2.0 hours, a sample was taken and detected with ninhydrin, revealing that the resin was colorless and transparent. 3. The reaction solution was removed and washed five times with DMF (150 mL) for 1 minute each time, and the waste liquid was drained until no more liquid flowed out.

[0268] Coupling steps for the remaining amino acids on the backbone Referring to the coupling method and input equivalents of Fmoc-Ser(tBu)-OH in Step 2, the amino acid sequence was sequentially coupled, and the order and the protecting group-containing amino acids used are shown below. TIFF2026503073000221.tif64170

[0269] The AA-11 peptide was obtained.

[0270] Step 3: Deprotection of the AA-11 peptide 1. The synthesized AA-11 peptide was activated by adding DMF (150 mL) for 10 minutes, and then discharged until no more liquid flowed out. 20% piperidine / DMF (150 mL) was added to the reaction column, and the reaction was continued for 10 minutes while bubbling nitrogen gas. The waste liquid was discharged until no more liquid flowed out. 20% piperidine / DMF (150 mL) was added to the reaction column again, and the reaction was continued for 10 minutes while bubbling nitrogen gas. A sample was taken and detected with ninhydrin. The resin was found to be deep yellow. The reaction solution was removed and washed with DMF (150 mL) 8 times, for 1 minute each time, to adjust the pH to about 7. The waste liquid was discharged until no more liquid flowed out.

[0271] Step 4: Coupling of Fmoc-Lys(Boc)-OH 1. 7.17 g (3.0 eq) of Fmoc-Lys(Boc)-OH, 2.57 g (4.0 eq) of DIC, and 2.07 g (3.0 eq) of HOBt were weighed and dissolved in 150 mL of DMF. The solution was then added to a reaction column while bubbling nitrogen gas through it. The nitrogen was adjusted so that the resin swelled evenly. After reacting at 2.25°C for 3.0 hours, a sample was taken and detected with ninhydrin, revealing that the resin was colorless and transparent. 3. The reaction solution was removed and washed five times with DMF (150 mL) for 1 minute each time, and the waste liquid was drained until no more liquid flowed out.

[0272] Coupling steps for the remaining amino acids on the backbone The amino acid sequence was sequentially linked by referring to the coupling method and order of Fmoc-Lys(Boc)-OH in Step 4, and the order and the protecting group-containing amino acids used are shown below. TIFF2026503073000222.tif160170

[0273] Step 5: Branched Chain Coupling 1. 300 mL of DCM was added to the reaction column to wash the resin four times. After the solvent was drained, 150 mL of a 20% hexafluoroisopropanol (HFIP)-DCM solution was added, and the reaction was carried out five times, for 30 minutes each time, while bubbling nitrogen gas. 2. The waste liquid was drained until no more liquid flowed out, and a sample was taken. When detected with ninhydrin, the resin appeared gray-green. 3. 150 mL of DCM and 150 mL of DMF were added successively to wash the resin alternately four times, and the waste liquid was discharged until no more liquid flowed out. 4. 10.08 g (5.0 eq) of Fmoc-Ida(Oall)-OH, 3.86 g (6.0 eq) of DIC, and 3.45 g (5.0 eq) of HOBt were weighed and dissolved in 150 mL of DMF. The solution was then added to a reaction column while bubbling nitrogen gas. The nitrogen was adjusted so that the resin swelled evenly. After reacting at 5.25°C for 3.0 hours, a sample was taken and detected with ninhydrin, revealing that the resin was colorless and transparent. 6. The reaction solution was removed and washed five times with DMF (180 mL) for 1 minute each time, and the waste liquid was drained until no more liquid flowed out.

[0274] Coupling steps for the remaining branches Referring to the coupling method and input equivalents of Fmoc-Ida(Oall)-OH in Step 5, the compounds shown in the table below were coupled sequentially. TIFF2026503073000223.tif29170

[0275] Step 6: Cyclization 1. 250 mL of DMF and 250 mL of DCM were added to the reaction column in this order to wash the resin alternately four times, and the waste liquid was discharged until no more liquid flowed out. 2. 300 mL of a mixed solvent of DCM, CH3CN, NMP, and DEA was prepared in a volume ratio of 3:3:2:2 and placed in a reaction column. 1.59 g (0.27 eq) of Pd(PPh3)4 was added, and the reaction was carried out for 30 minutes while bubbling nitrogen gas through the column. The waste liquid was discharged until no more liquid flowed out. 3. A sample was taken and detected with ninhydrin, and the resin turned reddish purple. 4. 250 mL of DMF and 250 mL of DCM were added successively, and the resin was washed alternately eight times. 5. 3.86 g (6.0 eq) of DIC and 3.45 g (5.0 eq) of HOBt were dissolved in 250 mL of DMF and placed in a reaction column. The reaction was carried out for 22 hours while bubbling nitrogen gas through the column. A sample was taken and detected with ninhydrin, revealing that the resin was very pale purple. 6. 250 mL of DMF and 250 mL of DCM were added successively, and the resin was washed alternately eight times. 7. 200 mL of MeOH and 200 mL of DCM were added successively, and the resin was washed four times alternately. 8. The resin was taken out and dried under vacuum until the weight no longer decreased, and the weight was measured, resulting in 32.5 g of peptide resin.

[0276] The structural formula of the obtained intermediate (peptide resin) is as follows: Nε(Boc‐Tyr(tBu)‐Aib‐Gln(Trt)‐Gly‐Thr(tBu)‐Phe‐Thr(tBu)‐Ser(tBu)‐Asp(OtBu)‐Tyr(tBu)‐Ser(tBu)‐Ile‐a‐MeLeu‐Lys 14 -Asp(OtBu)-Lys(Boc)-Lys 17 ‐Ala‐Gln(Trt)‐Aib‐Ala‐Phe‐Ile‐Glu(OtBu)‐Tyr(tBu)‐Leu‐Leu‐ Lys(Boc)‐Gly‐Gly‐Pro‐Ser(tBu)‐Ser(tBu)‐Gly‐Ala‐Pro‐Pro‐Pro‐Ser(tBu)‐Rink Linker ‐MBHA Resin(14,17(Nε(HOOC‐(CH2) 18 ‐COOtBu)‐Glu(ε‐OtBu)‐(AEEA)‐(2‐2‐oxoethyl)glycine))

[0277] Step 7: Cleavage of the peptide resin A 500 mL cleavage reagent was prepared by mixing trifluoroacetic acid (TFA), purified water (HO), triisopropylsilane (TIS), 3-(tritylthio)propionic acid (Mpa(Trt)-OH), and phenol (ArOH) in a volume ratio of TFA:HO:Mpa(Trt)-OH:TIS:ArOH = 82.5:2.5:5:5:5, and then pre-cooled to 10±3°C. The resin was slowly added to the cleavage reagent while stirring until the temperature of the reaction system stabilized, and the reaction was allowed to proceed for 4 hours while stirring and controlling the temperature at 18±3°C. The cleavage solution was filtered, concentrated to a viscous solution, and precipitated with methyl tert-butyl ether in an amount 12 to 15 times the volume of the concentrate. The precipitate was filtered, washed, and then dried under reduced pressure at room temperature to obtain 9.8 g of crude cyclic peptide.

[0278] Step 8. Chromatographic purification One-sixth of the crude cyclic peptide (9.8 g) was dissolved in 5% acetonitrile and 2% aqueous ammonia, and purified by high-performance liquid chromatography (HPLC) using a C18 silica gel matrix packing. Fractions with a purity of >90% were collected and combined. The purification chromatography system is shown in the table below. TIFF2026503073000224.tif40170

[0279] Step 9. Concentration and freeze-drying The fractions obtained in the above steps were concentrated to remove acetonitrile, filtered through a 0.22 μm Millipore filter membrane, loaded into a vial freeze-dryer, and freeze-dried to obtain 144 mg of the final target polypeptide product (purity 96.69%). The molecular weight of the polypeptide was confirmed by ESI-MS, with the calculated value [M+4H] / 4 being 1211.6 and the detected value being 1211.5.

[0280] Example 39 TIFF2026503073000225.tif56170 Referring to the synthesis of the polypeptide in Example 21, the polypeptide shown in Example 39 was obtained, in which the protecting groups of amino acids used for branched chain coupling were, in order, Fmoc-Ida(OAll)-OH, N-Boc-N'-Fmoc-Lys-OH, N-Boc-N'-Fmoc-Lys-OH, Fmoc-Glu-OtBu, and 20-(tert-butoxy)-20-oxoicosanoic acid. The molecular weight of the polypeptide was confirmed by ESI-MS, with a calculated value of [M+4H] / 4 of 1239.7 and a detected value of 1239.7.

[0281] Example 40 The polypeptide shown in Example 40 was obtained by referring to the synthesis of the polypeptide in Example 21 (TIFF2026503073000226.tif56170). The protecting groups of the amino acids used for branched chain coupling were, in order, Fmoc-Ida(OAll)-OH, N-Boc-N'-Fmoc-Lys-OH, N-Boc-N'-Fmoc-Lys-OH, Fmoc-Glu-OtBu, and 20-(tert-butoxy)-20-oxoicosanoic acid. The molecular weight of the polypeptide was confirmed by ESI-MS, with a calculated value of [M+4H] / 4 of 1254.2 and a detected value of 1254.1.

[0282] Example 41 TIFF2026503073000227.tif56170 The polypeptide shown in Example 41 was obtained by referring to the synthesis of the polypeptide in Example 38. The protecting groups for the amino acids used in the branched-chain coupling were, in order, Fmoc-Ida(OAll)-OH, N-Boc-N'-Fmoc-Lys-OH, N-Boc-N'-Fmoc-Lys-OH, Fmoc-Glu-OtBu, and 20-(tert-butoxy)-20-oxoicosanoic acid. The molecular weight of the polypeptide was confirmed by ESI-MS, with a calculated value of [M+4H] / 4 of 1239.4 and a detected value of 1239.3.

[0283] Example 42 The polypeptide shown in Example 42 was obtained by referring to the synthesis of the polypeptide in Example 21. The molecular weight of the polypeptide was confirmed by ESI-MS, and the calculated value [M+4H] / 4 was 1211.6, and the detected value was 1211.5.

[0284] Example 43 TIFF2026503073000229.tif62170MBHA Resin was used as the starting resin, and conventional Fmoc-protected amino acids were added. The condensation agent used was a DIC / HOBt system using DMF as the main reaction solvent and 20% PIP-DMF solution as the Fmoc removal solvent. The peptide backbone was synthesized from the C-terminus to the N-terminus by sequentially condensing the amino acids. After the backbone synthesis was completed, the peptide was deprotected by removing the -Mtt from the ε-amino group of Fmoc-Lys(Mtt)-OH at position A-26. Next, the side chains 1 to 4 were deprotected by (2-2-oxoethyl)-glycine, AEEA, γ Glu, 19-(bis(benzyloxy)phosphoryl)nonadecanoic acid. After sequential condensation of the two peptides, the ε-amino protecting group of Lys at position A-23 and the carboxyl protecting group of (2-2-oxoethyl)-glycine at position 1 of the side chain were removed, followed by the addition of a condensing agent to form a lactam ring, yielding the target peptide resin.

[0285] The specific steps are as follows: Step 1: Resin activation and deprotection 1. 15 g (5.1 mmol) of MBHA resin (S = 0.34 mmol / g) was added to a solid-phase reaction column, and 225 mL of DCM was added. The resin was left for 20 min to completely swell. The DCM was then drained. Next, 150 mL of DMF was added while bubbling nitrogen gas to wash the resin. This step was repeated once, and the solvent was drained. 20% piperidine / DMF (150 mL) was added to the reaction column, and the reaction was continued for 10 min while bubbling nitrogen gas. The waste solution was drained until no more liquid flowed out. 20% piperidine / DMF (150 mL) was added again to the reaction column, and the reaction was continued for 10 min while bubbling nitrogen gas. A sample was taken and detected with ninhydrin. The resin was gray-red. The reaction solution was then withdrawn and washed with 150 mL of DMF (8 times, 1 min each time, adjusting the pH to 7). The waste solution was drained until no more liquid flowed out.

[0286] Step 2: Coupling of Fmoc-Ser(tBu)-OH 1. 5.86 g (3.0 eq) of Fmoc-Ser(tBu)-OH, 2.57 g (4.0 eq) of DIC, and 2.07 g (3.0 eq) of HOBt were weighed and dissolved in 80 mL of DMF. The solution was then added to a reaction column while bubbling nitrogen gas through it. The nitrogen was adjusted so that the resin swelled evenly. After reacting at 2.25°C for 2.0 hours, a sample was taken and detected with ninhydrin, revealing that the resin was colorless and transparent. 3. The reaction solution was removed and washed five times with DMF (150 mL) for 1 minute each time, and the waste liquid was drained until no more liquid flowed out.

[0287] Coupling steps for the remaining amino acids on the backbone Referring to the coupling method and input equivalents of Fmoc-Ser(tBu)-OH in Step 2, the amino acid sequence was sequentially coupled, and the order and the protecting group-containing amino acids used are shown below. TIFF2026503073000230.tif64170

[0288] The AA-11 peptide was obtained.

[0289] Step 3: Deprotection of the AA-11 peptide 1. The synthesized AA-11 peptide was activated by adding DMF (150 mL) for 10 minutes, and then discharged until no more liquid flowed out. 20% piperidine / DMF (150 mL) was added to the reaction column, and the reaction was continued for 10 minutes while bubbling nitrogen gas. The waste liquid was discharged until no more liquid flowed out. 20% piperidine / DMF (150 mL) was added to the reaction column again, and the reaction was continued for 10 minutes while bubbling nitrogen gas. A sample was taken and detected with ninhydrin. The resin was found to be deep yellow. The reaction solution was removed and washed with DMF (150 mL) 8 times, for 1 minute each time, to adjust the pH to about 7. The waste liquid was discharged until no more liquid flowed out.

[0290] Step 4: Coupling of Fmoc-Glu(tBu)-OH 1. Weigh out 6.51 g (3.0 eq) of Fmoc-Glu(tBu)-OH, 2.57 g (4.0 eq) of DIC, and 2.07 g (3.0 eq) of HOBt, dissolve them in 150 mL of DMF, and then add them to a reaction column while bubbling nitrogen gas. Adjust the nitrogen so that the resin swells evenly. After reacting at 2.25°C for 3.0 hours, a sample was taken and detected with ninhydrin, revealing that the resin was colorless and transparent. 3. The reaction solution was removed and washed five times with DMF (150 mL) for 1 minute each time, and the waste liquid was drained until no more liquid flowed out.

[0291] Coupling steps for the remaining amino acids on the backbone The amino acid sequence was sequentially linked by referring to the coupling method and order of Fmoc-Glu(tBu)-OH in Step 4, and the order and the protecting group-containing amino acids used are shown below. TIFF2026503073000231.tif154170

[0292] Step 5: Branched Chain Coupling 1. 300 mL of DCM was added to the reaction column to wash the resin four times. After the solvent was drained, 150 mL of a 20% hexafluoroisopropanol (HFIP)-DCM solution was added, and the reaction was carried out five times, for 30 minutes each time, while bubbling nitrogen gas. 2. The waste liquid was drained until no more liquid flowed out, and a sample was taken. When detected with ninhydrin, the resin appeared gray-green. 3. 150 mL of DCM and 150 mL of DMF were added successively to wash the resin alternately four times, and the waste liquid was discharged until no more liquid flowed out. 4. 10.08 g (5.0 eq) of Fmoc-Ida(Oall)-OH, 3.86 g (6.0 eq) of DIC, and 3.45 g (5.0 eq) of HOBt were weighed and dissolved in 150 mL of DMF. The solution was then added to a reaction column while bubbling nitrogen gas. The nitrogen was adjusted so that the resin swelled evenly. After reacting at 5.25°C for 3.0 hours, a sample was taken and detected with ninhydrin, revealing that the resin was colorless and transparent. 6. The reaction solution was removed and washed five times with DMF (180 mL) for 1 minute each time, and the waste liquid was drained until no more liquid flowed out.

[0293] Coupling steps for the remaining branches Referring to the coupling method and input equivalents of Fmoc-Ida(Oall)-OH in Step 5, the compounds shown in the table below were coupled sequentially. TIFF2026503073000232.tif29170

[0294] Step 6: Cyclization 1. 250 mL of DMF and 250 mL of DCM were added to the reaction column in this order to wash the resin alternately four times, and the waste liquid was discharged until no more liquid flowed out. 2. 300 mL of a mixed solvent of DCM, CH3CN, NMP, and DEA was prepared in a volume ratio of 3:3:2:2 and placed in a reaction column. 1.59 g (0.27 eq) of Pd(PPh3)4 was added, and the reaction was carried out for 30 minutes while bubbling nitrogen gas through the column. The waste liquid was discharged until no more liquid flowed out. 3. A sample was taken and tested with ninhydrin, which revealed that the resin was purplish yellow. 4. 250 mL of DMF and 250 mL of DCM were added successively, and the resin was washed alternately eight times. 5. 3.86 g (6.0 eq) of DIC and 3.45 g (5.0 eq) of HOBt were dissolved in 250 mL of DMF and placed in a reaction column. The reaction was carried out for 23 hours while bubbling nitrogen gas through the column. A sample was taken and detected with ninhydrin, revealing that the resin was colorless. 6. 250 mL of DMF and 250 mL of DCM were added successively, and the resin was washed alternately eight times. 7. 200 mL of MeOH and 200 mL of DCM were added successively, and the resin was washed four times alternately. 8. The resin was taken out and dried under vacuum until the weight no longer decreased, and the weight was measured, resulting in 33 g of peptide resin.

[0295] The structural formula of the obtained intermediate (peptide resin) is as follows: Nε(Tyr(tBu)‐Aib‐Gln(Trt)‐Gly‐Thr(tBu)‐Phe‐Thr(tBu)‐Ser(tBu)‐Asp(OtBu)‐Tyr(tBu)‐Ser(tBu)‐Ile‐a‐MeLeu‐Lys 14 -Asp(OtBu)-Lys(Boc)-Lys 17 ‐Ala‐Gln(Trt)‐Aib‐Ala‐Phe‐Ile‐Glu(OtBu)‐Tyr(tBu)‐Leu‐Leu‐Glu(OtBu)‐Gly‐Gly‐Pro‐Ser(tBu)‐Ser(tBu)‐Gly‐Ala‐Pro‐Pro‐Pro‐Ser(tBu)‐Rink Linker ‐MBHA Resin(14,17(Nε(HOOC‐(CH2) 18 ‐PO(OBn)2)‐Glu(ε‐OtBu)‐(AEEA)‐(2‐2‐oxoethyl)glycine))

[0296] Step 7: Cleavage of the peptide resin A 500 mL cleavage reagent was prepared from trifluoroacetic acid (TFA), purified water (HO), triisopropylsilane (TIS), 3-(tritylthio)propionic acid (Mpa(Trt)-OH), and phenol (ArOH) in a volume ratio of TFA:HO:Mpa(Trt)-OH:TIS:ArOH = 82.5:2.5:5:5:5 and precooled to 10 ± 3 °C. The resin was slowly added to the cleavage reagent while stirring until the reaction temperature stabilized. The reaction was allowed to proceed for 8 h while maintaining the temperature at 18 ± 3 °C. The cleavage solution was filtered, concentrated to a viscous solution, and precipitated with 12–15 times the volume of the concentrate, methyl tert-butyl ether. The precipitate was filtered, washed, and dried under reduced pressure at room temperature to yield 8.8 g of crude cyclic peptide.

[0297] Step 8. Chromatographic purification 2.0 g of the crude cyclic peptide was dissolved in 5% acetonitrile and 2% aqueous ammonia, and purified by high-performance liquid chromatography using a C18 silica gel matrix packing. Fractions with a purity of >90% were collected and combined. The purification chromatography system is shown in the table below. TIFF2026503073000233.tif40170

[0298] Step 9. Concentration and freeze-drying The fractions obtained in the above steps were concentrated to remove acetonitrile, filtered through a 0.22 μm Millipore filter membrane, loaded into a vial freeze-dryer, and freeze-dried to obtain 28 mg of the final product of the target polypeptide (purity: 97.67%). The molecular weight of the polypeptide was confirmed by ESI-MS, with a calculated value [M] of 1220.9 and a detected value [M+H] of 1219.8.

[0299] Example 44 The polypeptide shown in Example 44 was obtained by referring to the synthesis of the polypeptide in Example 1. The molecular weight of the polypeptide was confirmed by ESI-MS, and the calculated value [M+4H] / 4 was 1259.2, and the detected value was 1258.0.

[0300] Example 45 The polypeptide shown in Example 45 was obtained by referring to the synthesis of the polypeptide in Example 21. The molecular weight of the polypeptide was confirmed by ESI-MS, and the calculated value [M+4H] / 4 was 1248.2, and the detected value was 1248.1.

[0301] Example 46 TIFF2026503073000236.tif42170 Referring to the synthesis of the polypeptide in Example 1, the polypeptide shown in Example 46 was obtained, in which the protecting groups for the amino acids used in the branched chain coupling were, in order, Fmoc-Ida(Oall)-OH, Fmoc-AEEA-OH, Fmoc-AEEA-OH, Fmoc-Glu-OtBu, and 19-(bis(benzyloxy)phosphoryl)nonadecanoic acid. The molecular weight of the polypeptide was confirmed by ESI-MS, with a calculated value [M] of 5067.61 and a detected value of 5066.61.

[0302] Example 47 The polypeptide shown in Example 47 was obtained by referring to the synthesis of the polypeptide in Example 21. The molecular weight of the polypeptide was confirmed by ESI-MS, and the calculated value [M] was 4900.56, and the detected value was 4900.62.

[0303] Example 48 The polypeptide shown in Example 48 was obtained by referring to the synthesis of the polypeptide in Example 21. The molecular weight of the polypeptide was confirmed by ESI-MS, and the calculated value [M] was 4885.56, and the detected value was 4885.50.

[0304] Example 49 The polypeptide shown in Example 49 was obtained by referring to the synthesis of the polypeptide in Example 21. The molecular weight of the polypeptide was confirmed by ESI-MS, and the calculated value [M] was 4857.51, and the detected value was 4857.55.

[0305] Example 50 TIFF2026503073000240.tif53170 The polypeptide shown in Example 50 was obtained with reference to the synthesis of the polypeptide in Example 21. The molecular weight of the polypeptide was confirmed by ESI-MS, and the calculated value [M] was 5002.59, and the detected value was 5002.62.

[0306] Example 51 The polypeptide shown in Example 51 was obtained by referring to the synthesis of the polypeptide in Example 21. The molecular weight of the polypeptide was confirmed by ESI-MS, and the calculated value [M] was 4856.57, and the detected value was 4856.48.

[0307] Example 52 TIFF2026503073000242.tif55170MBHA Resin was used as the starting resin, and conventional Fmoc-protected amino acids were added. The condensation agent used was a DIC / HOBt system using DMF as the main reaction solvent and 20% PIP-DMF solution as the Fmoc removal solvent. The peptide backbone was synthesized from the C-terminus to the N-terminus by sequentially condensing the amino acids. After the backbone synthesis was completed, the peptide was deprotected by removing the -Mtt from the ε-amino group of Fmoc-Lys(Mtt)-OH at position A-26. Next, side chains 1 to 5 ((2-2-oxoethyl)-glycine, AEEA, N-Boc-N'-Fmoc-Lys-OH, γ- Glu, 20-(tert-butoxy)-20-oxoicosanoic acid) were sequentially condensed, and then the ε-amino protecting group of Lys at position A-23 and the carboxyl protecting group of (2-2-oxoethyl)-glycine at position 1 of the side chain were removed. After that, a condensing agent was added to form a lactam ring, and the target peptide resin was obtained.

[0308] The specific steps are as follows: Step 1: Resin activation and deprotection 1. 15 g (5.1 mmol) of MBHA resin (S = 0.34 mmol / g) was added to a solid-phase reaction column, and 225 mL of DCM was added. The resin was left for 20 min to completely swell. The DCM was then drained. Next, 150 mL of DMF was added while bubbling nitrogen gas to wash the resin. This step was repeated once, and the solvent was drained. 20% piperidine / DMF (150 mL) was added to the reaction column, and the reaction was continued for 10 min while bubbling nitrogen gas. The waste solution was drained until no more liquid flowed out. 20% piperidine / DMF (150 mL) was added again to the reaction column, and the reaction was continued for 10 min while bubbling nitrogen gas. A sample was taken, and detection with ninhydrin revealed that the resin was gray-red. The reaction solution was then withdrawn and washed with 150 mL of DMF (8 times, 1 min each time, adjusting the pH to 7). The waste solution was drained until no more liquid flowed out. Step 2: Coupling of Fmoc-Ser(tBu)-OH 1. 5.86 g (3.0 eq) of Fmoc-Ser(tBu)-OH, 2.57 g (4.0 eq) of DIC, and 2.07 g (3.0 eq) of HOBt were weighed and dissolved in 80 mL of DMF. The solution was then added to a reaction column while bubbling nitrogen gas through it. The nitrogen was adjusted so that the resin swelled evenly. After reacting at 2.25°C for 2.0 hours, a sample was taken and detected with ninhydrin, revealing that the resin was colorless and transparent. 3. The reaction solution was removed and washed five times with DMF (150 mL) for 1 minute each time, and the waste liquid was drained until no more liquid flowed out.

[0309] Coupling steps for the remaining amino acids on the backbone Referring to the coupling method and input equivalents of Fmoc-Ser(tBu)-OH in Step 2, the amino acid sequence was sequentially coupled, and the order and the protecting group-containing amino acids used are shown below. TIFF2026503073000243.tif64170

[0310] The AA-11 peptide was obtained.

[0311] Step 3: Deprotection of the AA-11 peptide 1. The synthesized AA-11 peptide was activated by adding DMF (150 mL) for 10 minutes, and then discharged until no more liquid flowed out. 20% piperidine / DMF (150 mL) was added to the reaction column, and the reaction was continued for 10 minutes while bubbling nitrogen gas. The waste liquid was discharged until no more liquid flowed out. 20% piperidine / DMF (150 mL) was added to the reaction column again, and the reaction was continued for 10 minutes while bubbling nitrogen gas. A sample was taken and detected with ninhydrin. The resin was found to be deep yellow. The reaction solution was removed and washed with DMF (150 mL) 8 times, for 1 minute each time, to adjust the pH to about 7. The waste liquid was discharged until no more liquid flowed out. Step 4: Coupling of Fmoc-Glu(tBu)-OH 1. Weigh out 6.51 g (3.0 eq) of Fmoc-Glu(tBu)-OH, 2.57 g (4.0 eq) of DIC, and 2.07 g (3.0 eq) of HOBt, dissolve them in 150 mL of DMF, and then add them to a reaction column while bubbling nitrogen gas. Adjust the nitrogen so that the resin swells evenly. After reacting at 2.25°C for 3.0 hours, a sample was taken and detected with ninhydrin, revealing that the resin was colorless and transparent. 3. The reaction solution was removed and washed five times with DMF (150 mL) for 1 minute each time, and the waste liquid was drained until no more liquid flowed out.

[0312] Coupling steps for the remaining amino acids on the backbone The amino acid sequence was sequentially linked by referring to the coupling method and order of Fmoc-Glu(tBu)-OH in Step 4, and the order and the protecting group-containing amino acids used are shown below. TIFF2026503073000244.tif154170

[0313] Step 5: Branched Chain Coupling 1. 300 mL of DCM was added to the reaction column to wash the resin four times. After the solvent was drained, 150 mL of a 20% hexafluoroisopropanol (HFIP)-DCM solution was added, and the reaction was carried out five times, for 30 minutes each time, while bubbling nitrogen gas. 2. The waste liquid was drained until no more liquid flowed out, and a sample was taken. When detected with ninhydrin, the resin appeared gray-green. 3. 150 mL of DCM and 150 mL of DMF were added successively to wash the resin alternately four times, and the waste liquid was discharged until no more liquid flowed out. 4. 10.08 g (5.0 eq) of Fmoc-Ida(Oall)-OH, 3.86 g (6.0 eq) of DIC, and 3.45 g (5.0 eq) of HOBt were weighed and dissolved in 150 mL of DMF. The solution was then added to a reaction column while bubbling nitrogen gas. The nitrogen was adjusted so that the resin swelled evenly. After reacting at 5.25°C for 3.0 hours, a sample was taken and detected with ninhydrin, revealing that the resin was colorless and transparent. 6. The reaction solution was removed and washed five times with DMF (180 mL) for 1 minute each time, and the waste liquid was drained until no more liquid flowed out.

[0314] Coupling steps for the remaining branches Referring to the coupling method and input equivalents of Fmoc-Ida(Oall)-OH in Step 5, the compounds shown in the table below were coupled sequentially. TIFF2026503073000245.tif35170

[0315] Step 6: Cyclization 1. 250 mL of DMF and 250 mL of DCM were added to the reaction column in this order to wash the resin alternately four times, and the waste liquid was discharged until no more liquid flowed out. 2. 300 mL of a mixed solvent of DCM, CH3CN, NMP, and DEA was prepared in a volume ratio of 3:3:2:2 and placed in a reaction column. 1.59 g (0.27 eq) of Pd(PPh3)4 was added, and the reaction was carried out for 30 minutes while bubbling nitrogen gas through the column. The waste liquid was discharged until no more liquid flowed out. 3. A sample was taken and tested with ninhydrin, which revealed that the resin was purplish yellow. 4. 250 mL of DMF and 250 mL of DCM were added successively, and the resin was washed alternately eight times. 5. 3.86 g (6.0 eq) of DIC and 3.45 g (5.0 eq) of HOBt were dissolved in 250 mL of DMF and placed in a reaction column. The reaction was carried out for 22 hours while bubbling nitrogen gas through the column. A sample was taken and detected with ninhydrin, revealing that the resin was colorless. 6. 250 mL of DMF and 250 mL of DCM were added successively, and the resin was washed alternately eight times. 7. 200 mL of MeOH and 200 mL of DCM were added successively, and the resin was washed four times alternately. 8. The resin was taken out and dried under vacuum until the weight no longer decreased, and the weight was measured, resulting in 25.5 g of peptide resin.

[0316] The structural formula of the obtained intermediate (peptide resin) is as follows: Nε(Boc‐Tyr(tBu)‐Aib‐Gln(Trt)‐Gly‐Thr(tBu)‐Phe‐Thr(tBu)‐Ser(tBu)‐Asp(OtBu)‐Tyr(tBu)‐Ser(tBu)‐Ile‐a‐MeLeu‐Lys 14 -Asp(OtBu)-Lys(Boc)-Lys 17 ‐Ala‐Gln(Trt)‐Aib‐Ala‐Phe‐Ile‐Glu(OtBu)‐Tyr(tBu)‐Leu‐Leu‐Glu(OtBu)‐Gly‐Gly‐Pro‐Ser(tBu)‐Ser(tBu)‐Gly‐Ala‐Pro‐Pro‐Pro‐Ser(tBu)‐Rink Linker ‐MBHA Resin(14,17(Nε(HOOC‐(CH2) 18 ‐COOtBu)‐Boc(Lys)‐Glu(ε‐OtBu)‐(AEEA)‐(2‐2‐oxoethyl)glycine))

[0317] Step 7: Cleavage of the peptide resin A 500 mL cleavage reagent was prepared from trifluoroacetic acid (TFA), purified water (HO), triisopropylsilane (TIS), 3-(tritylthio)propionic acid (Mpa(Trt)-OH), and phenol (ArOH) in a volume ratio of TFA:HO:Mpa(Trt)-OH:TIS:ArOH = 82.5:2.5:5:5:5 and precooled to 10 ± 3 °C. The resin was slowly added to the cleavage reagent while stirring until the reaction temperature stabilized. The reaction was allowed to proceed for 4 h while maintaining the temperature at 18 ± 3 °C. The cleavage solution was filtered, concentrated to a viscous solution, and precipitated with 12–15 times the volume of the concentrate, methyl tert-butyl ether. The precipitate was filtered, washed, and dried under reduced pressure at room temperature to yield 8.6 g of crude cyclic peptide.

[0318] Step 8. Chromatographic purification 8.6 g of the crude cyclic peptide was dissolved in 5% acetonitrile and 2% aqueous ammonia, and purified by high-performance liquid chromatography using a C18 silica gel matrix packing. Fractions with a purity of >90% were collected and combined. The purification chromatography system is shown in the table below. TIFF2026503073000246.tif40170

[0319] Step 9. Concentration and freeze-drying The fractions obtained in the above steps were concentrated to remove acetonitrile, filtered through a 0.22 μm Millipore filter membrane, loaded into a vial freeze-dryer, and freeze-dried to obtain 1.1 g of the final target polypeptide product (purity 99.12%). The molecular weight of the polypeptide was confirmed by ESI-MS, with a calculated value [M] of 4972.62 and a detected value of 4971.42.

[0320] Example 53 The polypeptide shown in Example 53 was obtained by referring to the synthesis of the polypeptide in Example 52. The molecular weight of the polypeptide was confirmed by ESI-MS, and the calculated value [M] was 4985.61, and the detected value was 4985.42.

[0321] Example 54 The polypeptide shown in Example 54 was obtained by referring to the synthesis of the polypeptide in Example 52. The molecular weight of the polypeptide was confirmed by ESI-MS, and the calculated value [M] was 4970.65, and the detected value was 4969.65.

[0322] Biological Test Data Test 1: In vitro GLP-1R / GIPR / GCGR agonist activity test Method 1: A: Main materials 1) Cell line This cell line was constructed by Koryu Chemical Co., Ltd. For details, see the table below. TIFF2026503073000249.tif22170

[0323] 2) Reagents and consumables TIFF2026503073000250.tif69170

[0324] 3)Equipment TIFF2026503073000251.tif24170

[0325] B. Method I) Experimental materials Experimental buffer TIFF2026503073000252.tif40170

[0326] Preparation of detection reagents TIFF2026503073000253.tif29170

[0327] II) Experimental Method a) Preparation of compound plates: Test compounds were diluted 5-fold in 10 points from an initial concentration of 200 nM. b) Preparation of cell suspension: 1) Each cell line was cultured in complete medium at 37°C in 5% CO2. 2) After digestion with TrypLE, the cells were resuspended in the respective experimental buffers and inoculated into CulturPlate-384 cell culture plates at an inoculation density of 2000 cells per well and an inoculation volume of 15 μL per well. c) Measurement of agonist activity 1) Eu-cAMP tracer was frozen and thawed and diluted 50-fold with detection buffer, and Ulight-anti-cAMP was frozen and thawed and diluted 150-fold with detection buffer. 2) 5 μL of the test compound was added to each experimental well of a CulturPlate-384 cell culture plate, centrifuged at 200 g for 30 seconds, and allowed to stand at 37° C. for 30 minutes. 3) 10 μL of Eu-cAMP tracer was added to each experimental well, followed by 10 μL of Ultra-anti-cAMP. 4) The reaction plate was centrifuged at 200 g at room temperature for 30 seconds and then left at 25°C for 1 hour. 5) Data were collected on an Envision 2105, with excitation at 340 nm and emission at 665 nm and 615 nm.

[0328] C. Experimental Results TIFF2026503073000254.tif245170TIFF2026503073000255.tif40170

[0329] Conclusion: The polypeptide compounds of the present invention exhibit strong agonistic activity against GLP-1R, GIPR, and GCGR, with activity generally superior or comparable to that of LY3437943. The introduction of the "staple" structure and position, in particular, affects the activity of the polypeptide. Furthermore, in repeated experiments, the results of tests on other compounds showed the same trend. In a preferred embodiment, compared to the activity of the control LY3437943, the agonistic activity of the compounds of the present invention against GLP-1R was 0.05-5 times that of LY3437943, the agonistic activity against GIPR was 0.1-5 times that of LY3437943, and the agonistic activity against GCGR was 0.2-5 times that of LY3437943.

[0330] From the above, the compounds of the present invention have excellent in vitro GLP-1R / GIPR / GCGR agonist activity, and are overall superior or non-inferior to the control LY3437943.

[0331] Study 2: Pharmacokinetic properties of the compound in cynomolgus monkeys A. Experimental Objective Testing the pharmacokinetic profile of the compound in cynomolgus monkeys

[0332] B. Experimental Procedure Non-juvenile male cynomolgus monkeys were used, with three monkeys per compound. Whole blood samples were collected at 1, 2, 4, 8, 16, 24, 48, 72, 120, 168, and 240 hours after administration. Plasma was prepared and the drug concentrations were analyzed by LC-MS / MS. Pharmacokinetic parameters were calculated using Phoenix WinNonlin software.

[0333] C. Experimental Results The experimental results are shown in the table below.

[0334] TIFF2026503073000256.tif50170

[0335] Conclusion: In cynomolgus monkeys, the compounds of the present invention have a half-life T 1 / 2 had a half-life T 1 / 2 and exposure were significantly better, with overall benefit non-inferior to LY-3437943.

[0336] Furthermore, in repeated experiments, the experimental results of other compounds tested showed similar trends. In a preferred embodiment, the compounds of the present invention have a half-life T 1 / 2 and exposure value AUC INF is 1.1 to 2.5 times that of LY3437943, and its overall properties are superior to those of LY3437943.

[0337] In further studies, the compound of the present invention was pharmacokinetically tested in C57BL / 6 mice and SD rats. The experimental results showed the same tendency as the pharmacokinetic properties in cynomolgus monkeys, and the compound showed excellent pharmacokinetic properties in both mice and rats, with a half-life T 1 / 2 and exposure was also better or similar.

[0338] Test 3: Metabolic stability test in human kidney S9 A. Experimental Objective The metabolic stability of compounds in the human kidney was assessed to determine whether drugs are degraded by metabolic enzymes in the kidney, affecting their therapeutic efficacy and pharmacokinetic profile.

[0339] B. Experimental Procedure 1. The relevant solutions were prepared. 2.a) In the case of coenzymes (NADPH & UDPGA): NADPH and UDPGA were added to the incubation process. The final concentrations of KS9 Fractions, NADPH, and UDPGA were 1 mg / mL, 1 mM, and 2 mM, respectively. b) In the case of no coenzymes (NADPH & UDPGA): H2O was added to the culture medium. The final concentration of KS9 Fractions was 1 mg / mL. The mixture was preheated at 37°C for 10 min. 3. The reaction was initiated by adding 20 μM of the control compound or 100 μM of the test compound solution. In this study, 7-hydroxycoumarin and raloxifene were used as positive controls. The final concentration of the positive control compound was 0.2 μM, and the final concentration of the test compound was 1 μM. The cultures were incubated in a 37°C water bath. 4. At 0, 5, 5, 15, 30, and 60 min, equal volumes of samples were dispensed from the reaction mixture and acetonitrile was added to stop the reaction. The samples were centrifuged for 30 min. The supernatant was collected, mixed with ultrapure water, and used for LC-MS / MS analysis. 5. Data analysis: All calculations were performed using Microsoft Excel. Peak areas were determined from the extracted ion chromatograms, and slope values ​​were calculated.

[0340] C. Experimental Results TIFF2026503073000257.tif88170

[0341] Conclusion: The compounds of the present invention have excellent in vitro pharmacokinetic properties.

[0342] Study 4: Study of the pharmacodynamics of compounds in the DIO obese mouse model Experimental purpose: To evaluate the effects of repeated administration of the test substance (compound) on body weight and glycolipid metabolism.

[0343] In this study, mice aged 4-5 weeks were fed a high-fat diet (Research Diets: D12492) for 8 weeks as test animals. They were divided into groups based on body weight and fasting blood glucose levels. The average body weight of the model animals was 47.2±0.3g, the average body weight of the control animals was 27.9±0.3g, the average fasting blood glucose level of the model animals was 8.8±0.2mmol / L, and the average fasting blood glucose level of the control animals was 6.0±0.2mmol / L. Immediately after grouping, mice were divided into six groups and subcutaneously injected once every three days for 22 consecutive days. Both the normal control group and the model group were given a vehicle (20 mM citrate buffer). Body weight and food intake were measured twice weekly. Fasting blood glucose was measured on days 10 and 20 after administration, and an OGTT test was performed on day 20. Blood was collected on day 23 to examine liver function indices (ALT, AST, ALP) and serum lipid metabolism indices (TC, TG, HDL, LDL). Liver tissue was collected to calculate organ indices and examine liver lipid metabolism indices (liver TC, TG). Liver tissue was also examined pathologically (HE, Oil Red). The effects of the test substance on body weight and glycolipid metabolism in high-fat diet-induced obesity model mice were evaluated.

[0344] The experimental data for each group of animals were expressed as mean ± standard error (X ± SEM). P < 0.05 indicated a statistically significant difference. All statistical analyses were performed using Graphpad 8.0 software.

[0345] TIFF2026503073000258.tif44170

[0346] Conclusion: From the results in the table, it can be seen that the compounds of the present invention have significant weight loss effects, and show weight loss effects equal to or greater than those of LY3437943. Furthermore, the experimental results of testing other compounds of the present invention also show weight loss effects equal to or greater than those of LY3437943.

[0347] TIFF2026503073000259.tif39170

[0348] Conclusion: From the results in the table, it can be seen that the compounds of the present invention have significant blood glucose lowering effects, and exhibit blood glucose lowering effects equal to or greater than those of LY3437943. Furthermore, the experimental results of testing other compounds of the present invention also show blood glucose lowering effects equal to or greater than those of LY3437943.

[0349] TIFF2026503073000260.tif36170

[0350] Conclusion: From the results in the table, it can be seen that the compounds of the present invention have a significant effect of improving the liver weight to body weight ratio, and show an effect of improving the liver weight to body weight ratio that is equal to or greater than that of LY3437943. Furthermore, the experimental results of testing other compounds of the present invention also show an effect of improving the liver weight to body weight ratio that is equal to or greater than that of LY3437943.

[0351] TIFF2026503073000261.tif84170

[0352] Conclusion: From the results in the table, it can be seen that the compounds of the present invention have significant hepatic triglyceride lowering effects. Furthermore, the experimental results of testing other compounds of the present invention also show that they have hepatic triglyceride lowering effects equal to or greater than those of LY3437943.

[0353] Furthermore, the compounds of Example 38 and Example 52 were tested using the same experimental protocol, and the effects on the body weight change of DIO mice were as follows: TIFF2026503073000262.tif40170

[0354] Conclusion: From the results in the table, it can be seen that the compounds of Example 38 and Example 52 of the present invention also have significant weight-reducing effects, and exhibit weight-reducing effects equal to or greater than those of LY3437943.

[0355] Furthermore, the results of the pharmacodynamic test of the compounds of the present invention in the IPGTT test showed that all of the compounds of the present invention exhibited superior hypoglycemic activity compared to the vehicle group, and exhibited hypoglycemic activity equivalent to or greater than that of LY3437943.

[0356] Based on the above, the present invention newly designed and synthesized polypeptide compounds with a series of modified structures. These polypeptides have strong in vitro agonist activity against GLP-1R / GIPR / GCGR, excellent in vitro and in vivo pharmacokinetic properties, good stability, and significant effects such as weight loss, hypoglycemia, and hypolipidemics. The polypeptide compounds of the present invention are promising candidates for the development of long-acting GLP-1 / GIP / GCG multiple agonists.

Claims

1. The polypeptide sequence is shown in formula Z-3 below: X 5 X 0 X 6 GT FTSDY SIX 1 X 7 X 8 KX 9 X 10 X 11 X 0 X 4 FX 12 X 13 X 14 LLX 15 GG PSSGA PPPS 0 Formula Z-3 where: X ５ is selected from tyrosine (Tyr, Y) or histidine (His, H); X ０ teeth or Aib or alanine (Ala, A), X ６ is selected from glutamine (Gln, Q) or histidine (His, H), X １ are independently selected from α-methyl substituted leucine (α-MeLeu, α-MeL) or tyrosine (Tyr, Y); X ７ is selected from leucine (Leu, L) or lysine (Lys, K); X ８ is selected from aspartic acid (Asp, D) or glutamic acid (Glu, E); X ９ is selected from lysine (Lys, K), glutamine (Gln, Q) or glutamic acid (Glu, E); X １０ is selected from alanine (Ala, A) or tyrosine (Tyr, Y); X １１ is selected from lysine (Lys, K), glutamine (Gln, Q) or alanine (Ala, A); X ４ is selected from α-methyl substituted lysine (α-MeLys, α-MeK), D-lysine (dK), L-ornithine (L-Ornithine, L-Orn), alanine (Ala, A), lysine (Lys, K) or glutamic acid (Glu, E); X １２ is selected from valine (Val, V) or isoleucine (Ile, I), X １３ is selected from lysine (Lys, K), glutamine (Gln, Q) or glutamic acid (Glu, E); X １４ is selected from lysine (Lys, K), tryptophan (Trp, W), tyrosine (Tyr, Y), glutamic acid (Glu, E) or phenylalanine (Phe, F); X １５ is selected from lysine (Lys, K) or glutamic acid (Glu, E); S ０ teeth (i.e., the C-terminal amino acid is optionally amidated to a C-terminal primary amide), and the polypeptide compound is 1) amino acid side chains at positions i and i+j in the sequence can be linked by modifications to form a modified structure (staple body) similar to a "staple" structure, where i is independently selected from 14, 17, 19, 21, 24, or 25, and j is independently selected from 3, 4, 5, or 7; 2) The modification is carried out by modifying the amino or carboxyl groups on the side chains of the two amino acid unit structures. and a modification linked by condensation to a group represented by Including, X ２ teeth where "*" is X ３ and both ends are positions where the modified amino acid is linked to the corresponding amino group or carboxyl group of the modified amino acid, X ３ teeth is selected from the group R １ and R ２ teeth wherein m is selected from 1, 2 or 3; p is selected from 1 or 2; and n is selected from 8, 9 or 10.

2. S in the polypeptide sequence ０ teeth, The polypeptide according to claim 1 or a pharmaceutically acceptable salt thereof, wherein the amino acid is a group represented by the formula:

3. Amino acid X at position 2 of the polypeptide sequence ０ The polypeptide according to claim 1 and its pharmaceutically acceptable salts, characterized in that: is selected from Aib.

4. Amino acid X at position 20 of the polypeptide sequence ０ The polypeptide according to claim 1, and a pharmaceutically acceptable salt thereof, wherein is selected from Aib or A.

5. The polypeptide sequence is the following sequence: YAibQGT FTSDY SIα‐MeLLD KKAQAib KFIEY LLEGG PSSGA PPPS‐NH 2 (SEQ ID NO:1) YAibQGT FTSDY SIα‐MeLLD KKAQAib AFIKW LLKGG PSSGA PPPS‐NH 2 (SEQ ID NO:2) YAibQGT FTSDY SIα‐MeLLD KKAQAib AFIEK LLEGG PSSGA PPPS‐NH 2 (SEQ ID NO:3) HAibHGT FTSDY SIYLE KKYAAib EFVKW LLKGG PSSGA PPPS‐NH 2 (SEQ ID NO:4) HAibHGT FTSDY SIYLE KKYAAib KFVQW LLEGG PSSGA PPPS‐NH 2 (SEQ ID NO:5) YAibQGT FTSDY SIα‐MeLLD KKAQAib KFIEF LLEGG PSSGA PPPS‐NH 2 (SEQ ID NO:15) YAibQGT FTSDY SIα‐MeLLD KKAQAib EFIEY LLEGG PSSGA PPPS‐NH 2 (SEQ ID NO:16) YAibQGT FTSDY SIα‐MeLLD KKAQAib AFIKY LLEGG PSSGA PPPS‐NH 2 (SEQ ID NO:17) YAibQGT FTSDY SIα‐MeLLD KKAQAib KFIEY LLEGG PSSGA PPPS‐NH 2 (SEQ ID NO:18) YAibQGT FTSDY SIα‐MeLLD KKAKAib AFIKY LLEGG PSSGA PPPS‐NH 2 (SEQ ID NO:19) YAibQGT FTSDY SIα‐MeLLD KKAQAib KFIEY LLKGG PSSGA PPPS‐NH 2 (SEQ ID NO:20) YAibQGT FTSDY SIα‐MeLLD KKAQA α‐MeKFIEY LLEGG PSSGA PPPS‐NH 2 (SEQ ID NO:21) YAibQGT FTSDY SIα‐MeLLD KKAQAib d‐KFIEY LLEGG PSSGA PPPS‐NH 2 (SEQ ID NO:22) YAibQGT FTSDY SIα‐MeLLD KKAQAib L‐OrnFIEY LLEGG PSSGA PPPS‐NH 2 (SEQ ID NO:23) YAibQGT FTSDY SIα‐MeLKD KKAQAib AFIEY LLEGG PSSGA PPPS‐NH 2 (SEQ ID NO:24) The polypeptide according to any one of claims 1 to 2, and a pharmaceutically acceptable salt thereof, characterized in that it is selected from the following:

6. The polypeptide according to claim 5, wherein i is 14 and j is 3, and a pharmaceutically acceptable salt thereof.

7. The polypeptide according to claim 5, wherein i is 17 and j is 4, and a pharmaceutically acceptable salt thereof.

8. The polypeptide according to claim 5, wherein i is 17 and j is 7, and a pharmaceutically acceptable salt thereof.

9. The polypeptide according to claim 5, wherein i is 19 and j is 5, and a pharmaceutically acceptable salt thereof.

10. The polypeptide according to claim 5, wherein i is 21 and j is 7, and a pharmaceutically acceptable salt thereof.

11. The polypeptide according to claim 5, wherein i is 24 and j is 4, and a pharmaceutically acceptable salt thereof.

12. The polypeptide according to claim 5, wherein i is 25 and j is 4, and a pharmaceutically acceptable salt thereof.

13. The polypeptide according to claim 1, wherein m is selected from 1 and 2, and a pharmaceutically acceptable salt thereof.

14. The polypeptide of claim 1, wherein p is selected from 1, and a pharmaceutically acceptable salt thereof.

15. 2. The polypeptide of claim 1, wherein n is selected from 9, and a pharmaceutically acceptable salt thereof.

16. X ３ teeth, is selected from the group More preferably, The polypeptide according to claim 1 and its pharmaceutically acceptable salts, characterized in that the polypeptide is selected from the group represented by the formula:

17. The structural unit represented by is selected from the group More preferably, The polypeptide according to claim 1 and its pharmaceutically acceptable salts, characterized in that the polypeptide is selected from the group represented by the formula:

18. The structure of the staple body is The polypeptide according to claim 1 and its pharmaceutically acceptable salts, characterized in that the polypeptide is selected from the group represented by the formula:

19. A polypeptide compound represented by the following formula and a pharmaceutically acceptable salt thereof: (Compound 1) (Compound 2) (Compound 3) (Compound 4) (Compound 5) (Compound 6) (Compound 7) (Compound 8) (Compound 9) (Compound 10) (Compound 11) (Compound 12) (Compound 13) (Compound 14) (Compound 15) (Compound 16) (Compound 17) (Compound 18) (Compound 19) (Compound 20) (Compound 21) (Compound 39) (Compound 43) (Compound 44) (Compound 45) (Compound 46) (Compound 52)

20. 21. The polypeptide according to any one of claims 1 to 20, and a pharmaceutically acceptable salt thereof, characterized in that the salt is a salt formed with the following acids: inorganic acids include hydrochloric acid, hydrobromic acid, nitric acid, carbonic acid, bicarbonate, phosphoric acid, monohydrogen phosphate, dihydrogen phosphate, sulfuric acid, hydrogen sulfate, hydroiodic acid, and phosphorous acid; and organic acids include acetic acid, trifluoroacetic acid, propionic acid, isobutyric acid, maleic acid, malonic acid, benzoic acid, succinic acid, suberic acid, fumaric acid, lactic acid, mandelic acid, phthalic acid, benzenesulfonic acid, p-toluenesulfonic acid, citric acid, tartaric acid, methanesulfonic acid, pamoic acid, arginine, and glucuronic acid.

21. A pharmaceutical composition comprising the polypeptide according to any one of claims 1 to 20 or a pharmaceutically acceptable salt thereof.

22. Use of the polypeptide according to any one of claims 1 to 20 or a pharmaceutically acceptable salt thereof, and the pharmaceutical composition according to claim 21, in the preparation of a medicament for treating metabolic diseases and their associated diseases.

23. 23. The use according to claim 22, characterized in that the metabolic diseases include diabetes, obesity, non-alcoholic steatohepatitis and related diseases.

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