Peptides for use in synthesis of hypoglycemic elements

Abstract

Crystalline forms of peptide fragments, methods for their preparation and their use in the preparation of peptides are provided. The crystalline compound of the present invention can be used as an intermediate having improved purity and physical properties for peptide synthesis.

Description

[0001] Related Applications

[0002] This application claims priority to U.S. Provisional Patent Application No. 63 / 378,397, filed Oct. 5, 2022, and U.S. Provisional Patent Application No. 63 / 477,742, filed Dec. 29, 2022. The entire contents of these applications are incorporated herein by reference.

[0003] Sequence Listing

[0004] This application contains a Sequence Listing that has been electronically submitted in XML format and is hereby incorporated by reference in its entirety. An XML copy created on Oct. 3, 2023, is named 30267_WO.XML and is 51,063 bytes in size.

[0005] Disclosure

[0006] The present disclosure relates to peptides that can be used to prepare biopharmaceutical products, and methods for their preparation and use.

[0007] Diabetes is a chronic disorder characterized by hyperglycemia resulting from defects in insulin secretion, insulin action, or both. In type 2 diabetes (“T2D”), the combined effects of impaired insulin secretion and insulin resistance are associated with elevated blood glucose levels.

[0008] The GIP / GLP1 dual agonist tirzepatide (“TZP”) is described and claimed in U.S. Patent No. 9,474,780. Tirzepatide can be used to treat type 2 diabetes (“T2D”). Other processes for preparing tirzepatide and intermediates in those processes are described in U.S. Patent Application Publication 2022 / 0135639A1. Retatrutide (“GGG”), a GLP-1 / GIP / glucagon triple receptor agonist, is described in International Patent Publication Nos. WO 2019 / 125938 and WO 2021 / 034815. The GLP-1 / glucagon dual agonist mazdutide (“OXM”) is described and claimed in U.S. Patent No. 9,935,335 and International Patent Publication No. WO 2021 / 252829. Retatrutide and mazdutide can also be used to treat diabetes and promote weight loss. These patents and patent application publications are incorporated herein by reference in their entireties.

[0009] Other processes and intermediates are needed to improve the technology to simplify the production of peptides (such as tirzepatide, retatrutide, and marzodepeptide) with commercially desirable purity and volume. Similarly, efficient and environmentally friendly "green" processes, including stable intermediates, are needed to provide such peptides with fewer purification steps. There is also a need for improved environmentally friendly processes to provide peptide manufacturing processes that generate minimal waste streams, thereby enhancing environmental and operator safety. The preparation of large-scale, pharmaceutically excellent peptides presents many technical challenges that can affect the overall yield and purity. Processes that avoid the use of transition metals and / or harsh reaction conditions incompatible with peptide synthesis are needed.

[0010] The present disclosure seeks to meet these needs by providing novel intermediates and processes that can be used to manufacture peptides (such as tirzepatide, retatrutide, and marzodepeptide).

[0011] Tirzepatide ("TZP") has the structure of SEQ ID NO:1 as shown below:

[0012]

[0013] Retatrutide ("GGG") has the structure of SEQ ID NO:12 as shown below:

[0014]

[0015] Marzodepeptide ("OXM") has the structure of SEQ ID NO:16 as shown below:

[0016] SUMMARY OF THE INVENTION

[0018] The present disclosure describes peptide compounds that can be used to prepare tirzepatide (SEQ ID NO:1), retatrutide (SEQ ID NO:12), marzodepeptide (SEQ ID NO:16), and other peptides with improved efficiency.

[0019] In certain embodiments, the present disclosure describes a compound of formula (I) or a salt, solvate, or hydrate thereof,

[0020]

[0021] wherein R 1 is H or a protecting group; R 2 is H or a protecting group; R 3 is H or a protecting group; and R 4 is H or a protecting group; and wherein R 1 、R 2 、R 3 and R4 At least one of them is a protecting group. In certain embodiments, R 1 is H, Fmoc or Boc. In certain embodiments, R 2 is H or tert-butyl. In certain embodiments, R 4 is H or benzyl. In certain embodiments, R 3 is H, tert-butyl, benzyl, carboxybenzyl, methyl, allyl, cyclohexyl or trityl. In certain embodiments, at least two of R 1 , R 2 , R 3 and R 4 are H. In certain embodiments, at least two of R 1 , R 2 , R 3 and R 4 are protecting groups.

[0022] In certain embodiments, the compound of formula (I) is of the formula:

[0023]

[0024] In certain embodiments, the compound of formula (I) is of the formula:

[0025]

[0026] In certain embodiments, the compound of formula (I) is of the formula:

[0027]

[0028] In certain embodiments, the compound of formula (I) is of the formula:

[0029]

[0030] In certain embodiments, the compound of formula (I) is of the formula:

[0031]

[0032] In certain embodiments, the compound of formula (I) is a solvate. In certain embodiments, the solvate is produced by methyl tert-butyl ether (MTBE) or a mixture containing MTBE.

[0033] In certain embodiments, the compound of formula (I) is crystalline. In certain embodiments, the compound is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2θ of 5.2° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 8.4°, 8.8°, 10.4°, 15.5°, 17.1°, and 17.7°. In certain embodiments, the compound is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2θ of 6.1° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 10.3°, 14.9°, 16.8°, 18.1°, and 18.2°. In certain embodiments, the compound is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2θ of 6.2° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 8.9°, 12.3°, 14.9°, 15.4°, and 21.8°.

[0034] In certain embodiments, the present disclosure describes a method for synthesizing a compound of formula (I), the method comprising:

[0035] - reacting a compound of formula (Y prot )

[0036]

[0037] wherein R 1 and R 2 are protecting groups, with a compound of formula (Aib prot )

[0038] wherein R 5 is a protecting group, thereby forming a compound of formula (Y prot -Aib prot ),

[0039]

[0040] - removing the protecting group of R 5 and forming a compound of formula (Y prot -Aib)

[0041] - reacting a compound of formula (Y prot -Aib) with a compound of formula (E prot )

[0042] wherein R 3 is a protecting group, thereby forming a compound of formula (Y prot -Aib-E prot )

[0043]

[0044] - React the compound of formula (Y prot -Aib-E prot ) with the compound of formula (G prot )

[0045] wherein R 4 is a protecting group, thereby forming a compound of formula (Y prot -Aib-E prot -G prot )

[0046] and optionally

[0047] - Remove one or more of the protecting groups R 1 , R 2 , R 3 and R 4 .

[0048] In certain embodiments, the present disclosure describes a method for synthesizing the polypeptide of SEQ ID NO:1, the method comprising conjugating a compound of formula (I) to the N-terminus of the polypeptide of SEQ ID NO:2 through the C-terminus of the compound,

[0049] In certain embodiments, the present disclosure describes a method for synthesizing the polypeptide of SEQ ID NO:26, the method comprising conjugating a compound of formula (I) to the N-terminus of the polypeptide of SEQ ID NO:27 through the C-terminus of the compound.

[0050] In certain embodiments, the present disclosure describes a compound of formula (II) or a salt, solvate or hydrate thereof,

[0051]

[0052] wherein R 6 is H or a protecting group; R 7 is H or a protecting group; R 8 is H or a protecting group; R 9 is H or a protecting group; and R 10 is H or a protecting group. In certain embodiments, each protecting group is independently selected from Boc, Fmoc, tert-butyl and trityl groups. In certain embodiments, R 6 is H, Fmoc or Boc. In certain embodiments, R 7 is H or tert-butyl. In certain embodiments, R 8is H or tert-butyl. In certain embodiments, R 9 is H or tert-butyl. In certain embodiments, R 10 is H or benzyl. In certain embodiments, R 6 , R 7 , R 8 , R 9 and R 10 is at least one protecting group. In certain embodiments, R 6 , R 7 , R 8 , R 9 and R 10 is H.

[0053] In certain embodiments, the compound of formula (II) has the formula:

[0054]

[0055] In certain embodiments, the compound of formula (I) is a solvate. In certain embodiments, the solvate is produced by a solvent comprising heptane.

[0056] In certain embodiments, the compound of formula (I) is crystalline. In certain embodiments, the compound is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2θ of 7.7 - 7.9° ± 0.2 degrees and one or more peaks selected from 5.8°, 10.0°, 10.8 - 10.9°, 11.3 - 11.4°, 12.0 - 12.1°, 12.8°, 14.2 - 14.4° and 16.8 - 17.0° in the X-ray powder diffraction pattern. In certain embodiments, the compound is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2θ of 7.3° ± 0.2 degrees and one or more peaks selected from 5.1°, 5.7°, 7.6°, 9.5° and 12.4° in the X-ray powder diffraction pattern. In certain embodiments, the compound is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2θ of 7.8° ± 0.2 degrees and one or more peaks selected from 8.5°, 11.5°, 12.0°, 12.8°, 14.3°, 15.5°, 20.2° and 23.3° in the X-ray powder diffraction pattern. In certain embodiments, the compound is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2θ of 8.2 - 8.3° ± 0.2 degrees and one or more peaks selected from 5.9°, 7.7°, 9.2°, 10.2°, 11.3°, 13.8 - 13.9°, 15.5 - 15.7°, 17.1° and 18.5° in the X-ray powder diffraction pattern.

[0057] In certain embodiments, the present disclosure describes a method for synthesizing a polypeptide of SEQ ID NO:1, the method comprising (i) conjugating a compound of formula (II) to the C-terminus of a polypeptide of SEQ ID NO:3 through the N-terminus of the compound to form a polypeptide of SEQ ID NO:4; and (ii) conjugating the polypeptide of SEQ ID NO:4 to the N-terminus of a polypeptide of SEQ ID NO:5 through its C-terminus.

[0058] In certain embodiments, the present disclosure describes a compound of formula (III), or a salt, solvate or hydrate thereof,

[0059]

[0060] wherein R 11 is H or a protecting group; and R 12 is H or a protecting group. In certain embodiments, each protecting group is independently selected from Boc, Fmoc, tert-butyl and trityl groups. In certain embodiments, R 11 is H or tert-butyl. In certain embodiments, R 12 is H or tert-butyl. In certain embodiments, at least one of R 11 and R 12 is a protecting group. In certain embodiments, R 11 and R 12 are H.

[0061] In certain embodiments, the compound of formula (III) is a compound of the following formula:

[0062]

[0063] In certain embodiments, the compound of formula (III) is a solvate.

[0064] In certain embodiments, the compound of formula (III) is crystalline. In certain embodiments, the compound is in the form of a crystalline solid characterized by a peak at a diffraction angle 2θ of 8.0° ± 0.2 degrees in an X-ray powder diffraction pattern and one or more peaks selected from 7.0°, 10.3°, 14.1°, 15.2°, 16.7°, 18.0°, 19.0°, 19.7°, 20.8°, and 21.9°. In certain embodiments, the compound is in the form of a crystalline solid characterized by a peak at a diffraction angle 2θ of 9.0° ± 0.2 degrees in an X-ray powder diffraction pattern and one or more peaks selected from 5.7°, 9.9°, 16.2°, 17.1°, 17.9°, 18.1°, 18.4°, 18.8°, 19.9°, 20.1°, and 22.5°. In certain embodiments, the compound is in the form of a crystalline solid characterized by a peak at a diffraction angle 2θ of 10.5° ± 0.2 degrees in an X-ray powder diffraction pattern and one or more peaks selected from 5.6°, 11.9°, 13.3°, 15.4°, 15.6°, 18.1°, 19.9°, and 21.1°. In certain embodiments, the compound is in the form of a crystalline solid characterized by a peak at a diffraction angle 2θ of 10.7° ± 0.2 degrees in an X-ray powder diffraction pattern and one or more peaks selected from 4.9°, 14.8°, 20.3°, and 21.5°. In certain embodiments, the compound is in the form of a crystalline solid characterized by a peak at a diffraction angle 2θ of 10.5° ± 0.2 degrees in an X-ray powder diffraction pattern and one or more peaks selected from 5.9°, 10.5°, 10.9°, 12.1°, 13.1°, 15.9°, 17.5°, 20.9°, 21.1°, and 21.9°. In certain embodiments, the compound is in the form of a crystalline solid characterized by a peak at a diffraction angle 2θ of 7.8° ± 0.2 degrees in an X-ray powder diffraction pattern and one or more peaks selected from 11.3°, 11.5°, 15.4°, 15.6°, and 21.5°. In certain embodiments, the compound is in the form of a crystalline solid characterized by a peak at a diffraction angle 2θ of 10.0° ± 0.2 degrees in an X-ray powder diffraction pattern and one or more peaks selected from 8.1°, 12.5°, 13.5°, 14.7°, 17.8°, 18.8°, 20.0°, and 22.4°.In certain embodiments, the compound is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2θ of 21.1° ± 0.2 degrees in an X-ray powder diffraction pattern and one or more peaks selected from 5.6°, 10.5°, 10.8°, 11.9°, 15.4°, and 23.8°.

[0065] In certain embodiments, the present disclosure describes a method for synthesizing the polypeptide of SEQ ID NO:1, the method comprising (i) conjugating a compound of formula (III) to the C-terminus of the polypeptide of SEQ ID NO:6 through the N-terminus of the compound to form the polypeptide of SEQ ID NO:7; and (ii) conjugating the polypeptide of SEQ ID NO:7 to the N-terminus of the polypeptide of SEQ ID NO:8 through its C-terminus.

[0066] In certain embodiments, the present disclosure describes a compound of formula (IV), or a salt, solvate, or hydrate thereof,

[0067]

[0068] wherein R 13 is H or a protecting group; R 13* is H or a protecting group; R 14 is H or a protecting group; and R 15 is H or a protecting group. In certain embodiments, each protecting group is independently selected from Boc, Fmoc, tert-butyl, and trityl groups. In certain embodiments, R 13 is H, Fmoc, or Boc. In certain embodiments, R 13* is H. In certain embodiments, R 14 is H or tert-butyl. In certain embodiments, R 15 is H or tert-butyl. In certain embodiments, R 13 , R 13* , R 14 and R 15 in at least one of is a protecting group. In certain embodiments, R 13 , R 13* , R 14 and R 15 are H.

[0069] In certain embodiments, the compound of formula (IV) has the formula:

[0070]

[0071] In certain embodiments, the compound of formula (IV) is a solvate.

[0072] In certain embodiments, the compound of formula (IV) is crystalline. In certain embodiments, the compound is in the form of a crystalline solid characterized by a peak at a diffraction angle 2θ of 5.1° ± 0.2 degrees in an X-ray powder diffraction pattern and one or more peaks selected from 4.3°, 6.1°, 8.0°, 10.1°, and 18.7°. In certain embodiments, the compound is in the form of a crystalline solid characterized by a peak at a diffraction angle 2θ of 5.2° ± 0.2 degrees in an X-ray powder diffraction pattern and one or more peaks selected from 6.0°, 6.7°, 10.0°, 10.3°, 16.4°, 17.8°, 18.3°, 19.4°, and 22.4°.

[0073] In certain embodiments, the present disclosure describes a method for synthesizing the polypeptide of SEQ ID NO:1, the method comprising (i) conjugating the compound of formula (IV) to the C-terminus of the polypeptide of SEQ ID NO:9 through the N-terminus of the compound to form the polypeptide of SEQ ID NO:7; and (ii) conjugating the polypeptide of SEQ ID NO:7 to the N-terminus of the polypeptide of SEQ ID NO:8 through its C-terminus.

[0074] In certain embodiments, the compound of formula (IV) has the formula:

[0075]

[0076] wherein R 54 is H or a protecting group; R 55 is H or a protecting group; and R 56 is H or a protecting group. In certain embodiments, each protecting group is independently selected from Boc, Fmoc, tert-butyl, and trityl groups. In certain embodiments, R 54 is H or tert-butyl. In certain embodiments, R 55 is H or tert-butyl. In certain embodiments, R 56 is H or Boc. In certain embodiments, at least one of R 54 , R 55 , and R 56 is H. In certain embodiments, at least one of R 54 , R 55 , and R 56 is a protecting group.

[0077] In certain embodiments, the compound of formula (IV) has the structure of formula (IV-b):

[0078]

[0079] In certain embodiments, the compound of formula (IV-b) is a solvate. In certain embodiments, the compound is a solvate derived from acetone. In certain embodiments, the compound is a desolvate.

[0080] In certain embodiments, the compound of formula (IV-b) is crystalline. In certain embodiments, the compound is in the form of a crystalline solid characterized by peaks at diffraction angles 2-θ of 5.8° and 18.5° ± 0.2 degrees in an X-ray powder diffraction pattern and one or more peaks selected from 8.6°, 9.4°, 12.9°, 13.8°, 17.2°, and 19.4°. In certain embodiments, the compound is in the form of a crystalline solid characterized by peaks at diffraction angles 2-θ of 7.0 - 7.1° and 7.5 - 7.7° ± 0.2 degrees in an X-ray powder diffraction pattern and one or more peaks selected from 5.3 - 5.4°, 9.7 - 9.9°, and 14.7 - 14.9. In certain embodiments, the compound is in the form of a crystalline solid characterized by a peak at a diffraction angle 2-θ of 8.3° ± 0.2 degrees in an X-ray powder diffraction pattern and one or more peaks selected from 6.3°, 11.4°, 14.3°, and 16.6°. In certain embodiments, the compound is in the form of a crystalline solid characterized by a peak at a diffraction angle 2-θ of 7.2° ± 0.2 degrees in an X-ray powder diffraction pattern and one or more peaks selected from 6.8°, 8.6°, 15.8°, and 18.9°. In certain embodiments, the compound is in the form of a crystalline solid characterized by a peak at a diffraction angle 2-θ of 6.1° ± 0.2 degrees in an X-ray powder diffraction pattern and one or more peaks selected from 6.3°, 7.8°, 10.0°, and 12.4°.

[0081] In certain embodiments, the present disclosure describes a method for synthesizing a compound of formula (IV-b), the method comprising:

[0082] - reacting a compound of formula (Fmoc-G) with a compound of formula (P prot ) to form a compound of formula (Fmoc-G-P prot )

[0083]

[0084] wherein R 57 is a protecting group;

[0085] - removing the protecting group R 57 to form a compound of (Fmoc-G-P)

[0086]

[0087] - React the compound of formula (Fmoc-G-P) with the compound of formula (S prot2 ) to form a compound of formula (Fmoc-G-P-S prot2 )

[0088]

[0089] wherein R 54 and R 58 are protecting groups;

[0090] - Remove the protecting group R 58 to form a compound of (Fmoc-G-P-S prot1 )

[0091]

[0092] - React the compound of formula (Fmoc-G-P-S prot1 ) with the compound of formula (S prot2 ) to form a compound of formula (Fmoc-G-P-S prot1 -S prot2 )

[0093]

[0094] wherein R 55 and R 59 are protecting groups; and

[0095] - Remove the protecting group R 59 to form a compound of (Fmoc-F-G prot1 -S prot1 -S prot1 )

[0096]

[0097] - React the compound of formula (Fmoc-G-P-S prot1 -S prot1 ) with the compound of formula (G prot ) to form a compound of formula (Fmoc-G-P-S prot1 -S prot1 -G prot )

[0098]

[0099] wherein R 60 is a protecting group;

[0100] - React the compound of formula (Fmoc-G-P-Sprot1 -S prot1 -G prot ) the compound is converted into the compound as described in claim 36

[0101] and

[0102] - optionally removing one or more protecting groups R 54 、R 55 and R 56 。

[0103] In certain embodiments, each protecting group is independently selected from Boc, Fmoc, tert-butyl, and trityl groups.

[0104] In certain embodiments, the present disclosure describes a method for synthesizing the polypeptide of SEQ ID NO:12, the method comprising: (i) conjugating a compound of formula (IV-b) to the N-terminus of the polypeptide of SEQ ID NO:22 through the C-terminus of the compound, and (ii) conjugating the resulting compound to the C-terminus of the polypeptide of SEQ ID NO:23 through its N-terminus.

[0105] In certain embodiments, the present disclosure describes a method for synthesizing the polypeptide of SEQ ID NO:24, the method comprising conjugating a compound of formula (IV-b) to the N-terminus of the polypeptide of SEQ ID NO:22 through the C-terminus of the compound.

[0106] In certain embodiments, the present disclosure describes a method for synthesizing the polypeptide of SEQ ID NO:16, the method comprising conjugating a compound of formula (IV-b) to the C-terminus of the polypeptide of SEQ ID NO:25 through the N-terminus of the compound.

[0107] In certain embodiments, the present disclosure describes a method for synthesizing the polypeptide of SEQ ID NO:1, the method comprising: (i) conjugating a compound of formula (IV-b) to the N-terminus of the polypeptide of SEQ ID NO:8 through the C-terminus of the compound, and (ii) conjugating the resulting compound to the C-terminus of the polypeptide of SEQ ID NO:9 through its N-terminus.

[0108] In certain embodiments, the present disclosure describes a compound of formula (V), or a salt, solvate, or hydrate thereof,

[0109]

[0110] wherein R 16 is H or a protecting group; R 17 is H or a protecting group; R 18is H or a protecting group; R 19 is H or a protecting group; R 20 is H or a protecting group; and R 21 is H or a protecting group. In certain embodiments, each protecting group is independently selected from Boc, Fmoc, tert-butyl, and trityl groups. In certain embodiments, R 16 is H, Fmoc, or Boc. In certain embodiments, R 17 is H or tert-butyl. In certain embodiments, R 18 is H or tert-butyl. In certain embodiments, R 19 is H or tert-butyl. In certain embodiments, R 20 is H or tert-butyl. In certain embodiments, R 21 is H or benzyl. In certain embodiments, R 16 , R 17 , R 18 , R 19 , R 20 and R 21 in at least one is a protecting group. In certain embodiments, R 16 , R 17 , R 18 , R 19 , R 20 and R 21 are H.

[0111] In certain embodiments, the compound of formula (V) has the formula:

[0112]

[0113] In certain embodiments, the compound of formula (V) is a solvate.

[0114] In certain embodiments, the compound of formula (V) is crystalline. In certain embodiments, the compound is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2θ of 5.8 - 6.1° ± 0.2 degrees and one or more peaks selected from 6.7 - 7.1° and 8.8 - 9.0° in the X-ray powder diffraction pattern. In certain embodiments, the compound is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2θ of 5.0 - 5.2° ± 0.2 degrees and one or more peaks selected from 5.3 - 5.4°, 5.7 - 6.0°, 6.1 - 6.2°, 7.6 - 7.9°, and 8.7 - 9.1° in the X-ray powder diffraction pattern.

[0115] In certain embodiments, the present disclosure describes a method for synthesizing a polypeptide of SEQ ID NO:1, the method comprising (i) conjugating a compound of formula (V) to the C-terminus of a polypeptide of SEQ ID NO:3 through the N-terminus of the compound to form a polypeptide of SEQ ID NO:10; and (ii) conjugating the polypeptide of SEQ ID NO:10 to the N-terminus of a polypeptide of SEQ ID NO:11 through its C-terminus.

[0116] In certain embodiments, the present disclosure describes a compound of formula (VI), or a salt, solvate or hydrate thereof,

[0117]

[0118] wherein R 22 is H or a protecting group; R 23 is H or a protecting group; R 24 is H or a protecting group and R 25 is H or a protecting group. In certain embodiments, each protecting group is independently selected from Boc, Fmoc, tert-butyl and trityl groups. In certain embodiments, R 22 is H or Boc. In certain embodiments, R 23 is H or tert-butyl. In certain embodiments, R 24 is H or trityl. In certain embodiments, R 25 is H or tert-butyl. In certain embodiments, R 22 、R 23 、R 24 and R 25 at least one of is H. In certain embodiments, R 22 、R 23 、R 24 and R 25 at least one of is a protecting group.

[0119] In certain embodiments, the compound of formula (VI) is a compound of formula (VI-a):

[0120]

[0121] In certain embodiments, the compound of formula (VI) is a solvate. In certain embodiments, the compound is a solvate derived from amyl acetate, a mixture comprising amyl acetate, ethyl acetate, or a mixture comprising 2-methyltetrahydrofuran and tert-amyl methyl ether. In certain embodiments, the mixture comprising amyl acetate is selected from a mixture comprising amyl acetate and tert-butyl ethyl ether, a mixture comprising amyl acetate and tert-amyl methyl ether, or a mixture comprising amyl acetate and heptane. In certain embodiments, the compound is a desolvate or a partially desolvated compound.

[0122] In certain embodiments, the compound of formula (VI) is crystalline. In certain embodiments, the compound is in the form of a crystalline solid characterized by a peak at a diffraction angle 2-θ of 6.3 - 6.4° ± 0.2 degrees in an X-ray powder diffraction pattern and one or more peaks selected from 4.5°, 7.1°, 13.0 - 13.1°, 15.9 - 16.0°, and 18.4 - 18.6°. In certain embodiments, the compound is in the form of a crystalline solid characterized by a peak at a diffraction angle 2-θ of 7.0 - 7.2° ± 0.2 degrees in an X-ray powder diffraction pattern and one or more peaks selected from 5.0 - 5.4°, 7.6 - 7.7°, 8.8 - 8.9°, 9.4 - 9.5°, and 12.5 - 12.7°.

[0123] In certain embodiments, the present disclosure describes a method for synthesizing a compound of formula (VI), the method comprising:

[0124] - reacting a compound of formula (Y prot ) with a compound of formula (Aib prot ) to form a compound of formula (Y prot -Aib prot )

[0125]

[0126] wherein R 22 , R 23 and R 26 are protecting groups;

[0127] - removing the protecting group R 26 to form a compound of (Y prot -Aib)

[0128]

[0129] - reacting a compound of formula (Y prot -Aib) with a compound of formula (Q prot2 ) to form a compound of formula (Y prot-Aib-Q prot2 compound of

[0130]

[0131] wherein R 24 and R 27 are protecting groups;

[0132] - Remove the protecting group R 27 to form (Y prot -Aib-Q prot1 ) compound of

[0133]

[0134] - React the compound of formula (Y prot -Aib-Q prot1 ) with the compound of formula (G prot ) to form a compound of formula (VI)

[0135]

[0136] wherein R 25 is a protecting group; and

[0137] - Optionally remove one or more protecting groups R 22 , R 23 , R 24 and R 25 .

[0138] In certain embodiments, each protecting group is independently selected from Boc, Fmoc, tert-butyl, and trityl groups.

[0139] In certain embodiments, the present disclosure describes a method for synthesizing a polypeptide of SEQ ID NO:12, the method comprising conjugating a compound of formula (VI) to the N-terminus of a polypeptide of SEQ ID NO:13 through the C-terminus of the compound.

[0140] In certain embodiments, the present disclosure describes a method for synthesizing a polypeptide of SEQ ID NO:14, the method comprising conjugating a compound of formula (VI) to the N-terminus of a polypeptide of SEQ ID NO:15 through the C-terminus of the compound.

[0141] In certain embodiments, the present disclosure describes a compound of formula (VII), or a salt, solvate, or hydrate thereof,

[0142]

[0143] wherein R 28 is H or a protecting group; R29 is H or a protecting group, and R 30 is H or a protecting group. In certain embodiments, each protecting group is independently selected from Boc, Fmoc, tert-butyl, and trityl groups. In certain embodiments, R 28 is H or Boc. In certain embodiments, R 29 is H or trityl. In certain embodiments, R 30 is H or tert-butyl. In certain embodiments, R 28 , R 29 and R 30 in at least one of them is H. In certain embodiments, R 28 , R 29 and R 30 in at least one of them is a protecting group.

[0144] In certain embodiments, the compound of formula (VII) is a compound of formula (VII-a):

[0145]

[0146] In certain embodiments, the compound of formula (VII) is a solvate. In certain embodiments, the solvate is produced from any one of the following: a mixture of acetonitrile and methyl tert-butyl ether, a mixture of nitromethane and methyl tert-butyl ether, a mixture of tetrahydrofuran and methyl tert-butyl ether, methyl acetate, and ethyl acetate.

[0147] In certain embodiments, the compound of formula (VII) is crystalline. In certain embodiments, the compound is in the form of a crystalline solid, and the crystalline solid is characterized by a peak at a diffraction angle 2-θ of 4.8° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 5.6°, 6.2°, 14.8°, and 15.6°. In certain embodiments, the compound is in the form of a crystalline solid, and the crystalline solid is characterized by a peak at a diffraction angle 2-θ of 5.3° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 7.7°, 10.5°, 11.3°, 11.6°, and 14.4°. In certain embodiments, the compound is in the form of a crystalline solid, and the crystalline solid is characterized by peaks at diffraction angles 2-θ of 6.2° and 6.9° ± 0.2 degrees in the X-ray powder diffraction pattern.

[0148] In certain embodiments, the present disclosure describes a method for synthesizing a compound of formula (VII), the method comprising:

[0149] - reacting a compound of formula (H(dnp) prot ) with a compound of formula (Aib prot) The compound reacts to form a compound of formula (H(dnp) prot -Aib prot ) compound

[0150]

[0151] wherein R 28 and R 31 are protecting groups;

[0152] - Remove the protecting group R 31 to form (H(dnp) prot -Aib) compound

[0153]

[0154] - React the compound of formula (H(dnp) prot -Aib) with a compound of formula (Q prot2 ) to form a compound of formula (H(dnp) prot -Aib-Q prot2 ) compound

[0155]

[0156] wherein R 29 and R 32 are protecting groups;

[0157] - Remove the protecting group R 32 to form (H(dnp) prot -Aib-Q prot1 ) compound

[0158]

[0159] - React the compound of formula (H(dnp) prot -Aib-Q prot1 ) with a compound of formula (G prot ) to form a compound of formula (VII)

[0160]

[0161] wherein R 30 is a protecting group; and

[0162] - Optionally remove one or more protecting groups R 28 、R 29 and R 30 .

[0163] In certain embodiments, each protecting group is independently selected from Boc, Fmoc, tert-butyl, and trityl groups.

[0164] In certain embodiments, the present disclosure describes a method for synthesizing the polypeptide of SEQ ID NO:16, the method comprising conjugating a compound of formula (VII) to the N-terminus of a polypeptide of SEQ ID NO:17 through the C-terminus of said compound.

[0165] In certain embodiments, the present disclosure describes a compound of formula (VIII), or a salt, solvate or hydrate thereof,

[0166]

[0167] wherein R 33 is H or a protecting group; R 34 is H or a protecting group; and R 35 is H or a protecting group. In certain embodiments, each protecting group is independently selected from Boc, Fmoc, tert-butyl and trityl groups. In certain embodiments, R 33 is H or Boc. In certain embodiments, R 34 is H or trityl. In certain embodiments, R 35 is H or tert-butyl. In certain embodiments, at least one of R 33 , R 34 and R 35 is H. In certain embodiments, at least one of R 33 , R 34 and R 35 is a protecting group.

[0168] In certain embodiments, the compound of formula (VIII) is a compound of formula (VIII-a):

[0169]

[0170] In certain embodiments, the compound of formula (VIII) is a solvate. In certain embodiments, the solvate is produced from any one of the following: a mixture of tetrahydrofuran and methyl tert-butyl ether, a mixture of tetrahydrofuran and heptane, a mixture of 1,4-dioxane and water, a mixture of ethyl acetate and methyl tert-butyl ether, and a mixture of acetonitrile and methyl tert-butyl ether.

[0171] In certain embodiments, the compound of formula (VIII) is crystalline. In certain embodiments, the compound is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2-θ of 4.7° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 5.5°, 8.2°, 10.1°, 11.8°, 13.3°, 13.6°, and 18.9°. In certain embodiments, the compound is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2-θ of 5.8° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 5.3°, 8.9°, 9.2°, 15.2°, 18.6°, and 19.5°.

[0172] In certain embodiments, the present disclosure describes a method for synthesizing a compound of formula (VIII), the method comprising:

[0173] - reacting a compound of formula (H(trt) prot ) with a compound of formula (Aib prot ) to form a compound of formula (H(trt) prot -Aib prot )

[0174]

[0175] wherein R 33 and R 36 are protecting groups;

[0176] - removing the protecting group R 36 to form a compound of (H(trt) prot -Aib)

[0177]

[0178] - reacting a compound of formula (H(trt) prot -Aib) with a compound of formula (Q prot2 ) to form a compound of formula (H(trt) prot -Aib-Q prot2 )

[0179]

[0180] wherein R 33 and R 37 are protecting groups;

[0181] - removing the protecting group R 37 to form a compound of (H(trt) prot -Aib-Q prot1 )

[0182]

[0183] - React a compound of formula (H(trt) prot -Aib-Q prot1 ) with a compound of formula (G prot ) to form a compound of formula (VIII)

[0184]

[0185] wherein R 35 is a protecting group; and

[0186] - Optionally remove one or more protecting groups R 33 , R 34 and R 35 .

[0187] In certain embodiments, each protecting group is independently selected from Boc, Fmoc, tert-butyl, and trityl groups.

[0188] In certain embodiments, the present disclosure describes a method for synthesizing a polypeptide of SEQ ID NO:16, the method comprising conjugating a compound of formula (VIII) to the N-terminus of a polypeptide of SEQ ID NO:17 through the C-terminus of the compound.

[0189] In certain embodiments, the present disclosure describes a compound of formula (IX), or a salt, solvate, or hydrate thereof,

[0190]

[0191] wherein R 38 is H or a protecting group; R 39 is H or a protecting group; R 40 is H or a protecting group; R 41 is H or a protecting group; R 42 is H or a protecting group; and R 43 is H or a protecting group. In certain embodiments, each protecting group is independently selected from Boc, Fmoc, tert-butyl, and trityl groups. In certain embodiments, R 38 is H or Fmoc. In certain embodiments, R 39 is H or tert-butyl. In certain embodiments, R 40 is H or tert-butyl. In certain embodiments, R 41 is H or tert-butyl. In certain embodiments, R 42 is H or Boc. In certain embodiments, R 43 is H or tert-butyl. In certain embodiments, R38 , R 39 , R 40 , R 41 , R 42 and R 43 At least one of and R is H. In certain embodiments, R 38 , R 39 , R 40 , R 41 , R 42 and R 43 At least one of and R is a protecting group.

[0192] In certain embodiments, the compound of formula (IX) is a compound of formula (IX-a):

[0193]

[0194] In certain embodiments, the compound of formula (IX) is a solvate. In certain embodiments, the solvate is produced from any one of the following: a mixture of methyl acetate and dibutyl ether, a mixture of acetone and dibutyl ether, a mixture of acetonitrile and dibutyl ether, a mixture of ethyl acetate and dibutyl ether, a mixture of methyl acetate and heptane, and a mixture of methyl ethyl ketone and dibutyl ether. In certain embodiments, the compound is a desolvate or is anhydrous.

[0195] In certain embodiments, the compound of formula (IX) is crystalline. In certain embodiments, the compound is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2-θ of 5.3° ± 0.2 degrees and one or more peaks selected from 6.0°, 6.9°, 7.2°, 8.0°, 12.2° and 15.6° in the X-ray powder diffraction pattern. In certain embodiments, the compound is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2-θ of 5.8° ± 0.2 degrees and one or more peaks selected from 4.4°, 6.6°, 10.1°, 11.4°, 13.4° and 15.5° in the X-ray powder diffraction pattern. In certain embodiments, the compound is in the form of a crystalline solid, the crystalline solid being characterized by peaks at diffraction angles 2-θ of 4.5° and 5.5° ± 0.2 degrees and one or more peaks selected from 6.0° and 7.3° in the X-ray powder diffraction pattern.

[0196] In certain embodiments, the present disclosure describes a method for synthesizing a compound of formula (IX), the method comprising:

[0197] - reacting a compound of formula (D prot ) with a compound of formula (Y prot2 ) to form a compound of formula (Dprot -Y prot2 compound of

[0198]

[0199] wherein R 38 and R 39 and R 40 and R 44 are protecting groups;

[0200] - Remove the protecting group R 44 to form a compound of (D prot -Y prot1 )

[0201]

[0202] - React the compound of formula (D prot -Y prot1 ) with a compound of formula (S prot2 ) to form a compound of formula (D prot -Y prot1 -S prot2 )

[0203]

[0204] wherein R 41 and R 45 are protecting groups;

[0205] - Remove the protecting group R 45 to form a compound of (D prot -Y prot1 -S prot1 )

[0206]

[0207] - React the compound of formula (D prot -Y prot1 -S prot1 ) with a compound of formula (K prot2 ) to form a compound of formula (IX)

[0208]

[0209] wherein R 42 and R 43 are protecting groups; and

[0210] - Optionally remove one or more protecting groups R 38 and R 39 and R 40 and R 41 and R 42and R 43 。

[0211] In certain embodiments, the protecting group is selected from Boc, Fmoc, tert-butyl, and trityl groups.

[0212] In certain embodiments, the present disclosure describes a method for synthesizing the polypeptide of SEQ ID NO:16, the method comprising: (i) conjugating a compound of formula (IX) to the N-terminus of the polypeptide of SEQ ID NO:18 through the C-terminus of the compound, and (ii) conjugating the compound to the C-terminus of the polypeptide of SEQ ID NO:19 through its N-terminus.

[0213] In certain embodiments, the present disclosure describes a compound of formula (X), or a salt, solvate, or hydrate thereof,

[0214]

[0215] wherein R 46 is H or a protecting group; R 47 is H or a protecting group; R 48 is H or a protecting group; R 49 is H or a protecting group; R 50 is H or a protecting group; and R 51 is H or a protecting group. In certain embodiments, each protecting group is independently selected from Boc, Fmoc, tert-butyl, and trityl groups. In certain embodiments, R 46 is H or tert-butyl. In certain embodiments, R 47 is H or tert-butyl. In certain embodiments, R 48 is H or Boc. In certain embodiments, R 49 is H or Fmoc. In certain embodiments, R 50 is H or tert-butyl. In certain embodiments, R 51 is H or tert-butyl. In certain embodiments, R 46 、R 47 、R 48 、R 49 、R 50 and R 51 is at least one of H. In certain embodiments, R 46 、R 47 、R 48 、R 49 、R 50 and R 51 is at least one of a protecting group.

[0216] In certain embodiments, the compound of formula (X) is a compound of formula (X-a):

[0217]

[0218] In certain embodiments, the compound of formula (X) is a solvate. In certain embodiments, the compound is a solvate derived from ethanol or isopropanol. In certain embodiments, the compound is a desolvate.

[0219] In certain embodiments, the compound of formula (X) is crystalline. In certain embodiments, the compound is in the form of a crystalline solid, the crystalline solid being characterized by peaks at diffraction angles 2-θ of 18.1° and 18.7° ± 0.2 degrees in an X-ray powder diffraction pattern and one or more peaks selected from 5.7°, 8.7°, 13.7°, 14.3°, 15.9° and 16.2°. In certain embodiments, the compound is in the form of a crystalline solid, the crystalline solid being characterized by peaks at diffraction angles 2-θ of 5.9° and 10.5° ± 0.2 degrees in an X-ray powder diffraction pattern and one or more peaks selected from 7.1°, 8.9°, 14.6° and 16.6°. In certain embodiments, the compound is in the form of a crystalline solid, the crystalline solid being characterized by peaks at diffraction angles 2-θ of 7.8° and 20.3° ± 0.2 degrees in an X-ray powder diffraction pattern and one or more peaks selected from 5.8°, 15.5° and 19.5°. In certain embodiments, the compound is in the form of a crystalline solid, the crystalline solid being characterized by peaks at diffraction angles 2-θ of 5.9° and 7.4° ± 0.2 degrees in an X-ray powder diffraction pattern and one or more peaks selected from 6.5°, 6.9° and 14.8°.

[0220] In certain embodiments, the present disclosure describes a method for synthesizing a compound of formula (X), the method comprising:

[0221] - reacting a compound of formula (Y prot ) with a compound of formula (S prot2 ) to form a compound of formula (Y prot -S prot2 )

[0222]

[0223] wherein R 46 , R 47 , R 48 and R 52 are protecting groups;

[0224] - removing the protecting group R 52 to form a compound of (Y prot -S prot1 )

[0225]

[0226] - React the compound of formula (Y prot -S prot1 ) with the compound of formula (K prot2 ) to form a compound of formula (Y prot -S prot1 -K prot2 )

[0227]

[0228] wherein R 49 and R 53 are protecting groups;

[0229] - Remove the protecting group R 53 to form (Y prot -S prot1 -K prot1 ) compound

[0230]

[0231] - React the compound of formula (Y prot -S prot1 -K prot1 ) with the compound of formula (Y prot2 ) to form a compound of formula (X)

[0232]

[0233] wherein R 50 and R 51 are protecting groups; and

[0234] - Optionally remove one or more protecting groups R 46 , R 47 , R 48 , R 49 , R 50 and R 51 .

[0235] In certain embodiments, the protecting group is selected from Boc, Fmoc, tert-butyl and trityl groups.

[0236] In certain embodiments, the present disclosure describes a method for synthesizing the polypeptide of SEQ ID NO:16, the method comprising: (i) conjugating the compound of formula (X) to the N-terminus of the polypeptide of SEQ ID NO:20 through the C-terminus of the compound, and (ii) conjugating the resulting compound to the C-terminus of the polypeptide of SEQ ID NO:21 through its N-terminus.

[0237] In certain embodiments, the present disclosure describes a compound of formula (XI), or a salt, solvate, or hydrate thereof,

[0238]

[0239] wherein R 64 is H or a protecting group; R 65 is H or a protecting group; and R 66 is H or a protecting group. In certain embodiments, each protecting group is independently selected from Boc, Fmoc, tert-butyl, and trityl groups. In certain embodiments, at least one of R 64 , R 65 , and R 66 is H. In certain embodiments, at least one of R 64 , R 65 , and R 66 is a protecting group.

[0240] In certain embodiments, the compound of formula (XI) is a compound of the following formula:

[0241]

[0242] In certain embodiments, the compound of formula (XI) is a solvate.

[0243] In certain embodiments, the compound of formula (XI) is crystalline. In certain embodiments, the compound is in the form of a crystalline solid, the crystalline solid being characterized by peaks at diffraction angles 2-θ ± 0.2 degrees at 6.1° and 8.5° and one or more peaks selected from 5.8°, 16.9°, 18.5°, 18.8°, 19.3°, and 20.9 in the X-ray powder diffraction pattern.

[0244] In certain embodiments, the present disclosure describes a compound of formula (XII), or a salt, solvate, or hydrate thereof,

[0245]

[0246] wherein R 61 is H or a protecting group; R 62 is H or a protecting group; and R 63 is H or a protecting group. In certain embodiments, each protecting group is independently selected from Boc, Fmoc, tert-butyl, and trityl groups. In certain embodiments, R 61 is H or tert-butyl. In certain embodiments, R 62 is H or tert-butyl. In certain embodiments, R 63is H or tert-butyl. In certain embodiments, R 61 , R 62 and R 63 is at least one of H. In certain embodiments, R 61 , R 62 and R 63 is at least one of a protecting group.

[0247] In certain embodiments, the compound of formula (XII) is a compound of formula (XII-a):

[0248]

[0249] In certain embodiments, the compound of formula (XII) is a solvate. In certain embodiments, the compound is a desolvate or is anhydrous.

[0250] In certain embodiments, the compound of formula (XII) is crystalline. In certain embodiments, the compound is in the form of a crystalline solid characterized by a peak at a diffraction angle 2-θ of 11.4° ± 0.2 degrees in an X-ray powder diffraction pattern and one or more peaks selected from 6.0°, 8.9°, 12.7°, 13.6°, 14.6°, 17.0°, and 18.8°. In certain embodiments, the compound is in the form of a crystalline solid characterized by a peak at a diffraction angle 2-θ of 10.6° ± 0.2 degrees in an X-ray powder diffraction pattern and one or more peaks selected from 7.1°, 12.1°, 13.6°, 14.2°, 15.2°, 16.0°, and 16.8°. In certain embodiments, the compound is in the form of a crystalline solid characterized by peaks at diffraction angles 2-θ of 10.1° and 15.5° ± 0.2 degrees in an X-ray powder diffraction pattern and one or more peaks selected from 6.1°, 8.7°, 11.4°, 16.6°, and 19.2°.

[0251] In certain embodiments, the present disclosure describes a compound of formula (XIII), or a salt, solvate, or hydrate thereof,

[0252]

[0253] wherein R 67 is H or a protecting group; R 68 is H or a protecting group; and R 69 is H or a protecting group. In certain embodiments, each protecting group is independently selected from Boc, Fmoc, tert-butyl, and trityl groups. In certain embodiments, R 67 is H or tert-butyl. In certain embodiments, R68 is H or tert-butyl. In certain embodiments, R 69 is H or tert-butyl. In certain embodiments, R 67 , R 68 and R 69 in at least one of them is H. In certain embodiments, R 67 , R 68 and R 69 in at least one of them is a protecting group.

[0254] In certain embodiments, the compound of formula (XIII) is a compound of the following formula:

[0255]

[0256] In certain embodiments, the compound of formula (XIII) is a solvate. In certain embodiments, the compound is a desolvate or is anhydrous.

[0257] In certain embodiments, the compound of formula (XIII) is crystalline. In certain embodiments, the compound is in the form of a crystalline solid, and the crystalline solid is characterized by a peak at a diffraction angle 2-θ of 5.0° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 8.3, 9.7, and 11.2°. In certain embodiments, the compound is in the form of a crystalline solid, and the crystalline solid is characterized by a peak at a diffraction angle 2-θ of 7.2° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 5.3, 8.1, 14.4, and 16.2°.

[0258] In certain embodiments, the present disclosure describes a compound of formula (XIV), or a salt, solvate, or hydrate thereof,

[0259]

[0260] wherein R 70 is H or a protecting group; R 71 is H or a protecting group; R 72 is H or a protecting group; R 73 is H or a protecting group; and R 74 is H or a protecting group. In certain embodiments, each protecting group is independently selected from Boc, Fmoc, tert-butyl, and trityl groups. In certain embodiments, R 70 is H, Fmoc, or tert-butyl. In certain embodiments, R 71 is H or tert-butyl. In certain embodiments, R 72 is H or tert-butyl. In certain embodiments, R 73is H or tert-butyl. In certain embodiments, R 74 is H, Fmoc or tert-butyl. In certain embodiments, R 70 , R 71 , R 72 , R 73 and R 74 in at least one of them is H. In certain embodiments, R 70 , R 71 , R 72 , R 73 and R 74 in at least one of them is a protecting group.

[0261] In certain embodiments, the compound of formula (XIV) is a compound of the following formula:

[0262]

[0263] In certain embodiments, the compound of formula (XIV) is a solvate. In certain embodiments, the compound is a desolvate or is anhydrous

[0264] In certain embodiments, the compound of formula (XIV) is crystalline. In certain embodiments, the compound is in the form of a crystalline solid, and the crystalline solid is characterized by a peak at a diffraction angle 2-θ of 7.5° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 6.1, 8.7, 10.6, 15.0, 16.1 and 18.6°. Brief Description of the Drawings

[0266] Figure 1A , Figure 1B and Figure 1C respectively show the representative X-ray powder diffraction ("XRPD") patterns of the Y-Aib-E-G tetramer in Form A, Form B and Form C.

[0267] Figure 2A , Figure 2B , Figure 2C and Figure 2D respectively show the representative XRPD patterns of the T-F-T-S tetramer in Form A, Form B, Form C and Form D.

[0268] Figure 3 shows the polymorphic relationship diagram of various crystalline solid forms of P-S-S-G-NH2.

[0269] Figure 4A , Figure 4B , Figure 4C , Figure 4D , Figure 4E , Figure 4F ,Figure 4G and Figure 4H show the representative XRPD patterns of the P-S-S-G-NH2 tetramer in Forms A, B, C, D, E, F, G, and H, respectively.

[0270] Figure 5A and Figure 5B show the representative XRPD patterns of the G-P-S-S-G-NH2 pentamer in Forms A and B, respectively.

[0271] Figure 6A and Figure 6B show the representative XRPD patterns of the T-F-T-S-D pentamer in Forms A and B, respectively. In Figure 6A and Figure 6B the traces show the results of the products obtained in various experiments.

[0272] Figure 7A and Figure 7B show the representative XRPD patterns of the Y-Aib-Q-G tetramer in Forms A and B, respectively.

[0273] Figure 8A , Figure 8B and Figure 8C show the representative XRPD patterns of the H(dnp)-Aib-Q-G tetramer in Forms A, B, and C, respectively.

[0274] Figure 9A and Figure 9B show the representative XRPD patterns of the H(trt)-Aib-Q-G tetramer in Forms A and B, respectively.

[0275] Figure 10A , Figure 10B and Figure 10C show the representative XRPD patterns of the D-Y-S-K tetramer in Forms A, B, and C, respectively.

[0276] Figure 11 shows the polymorph relationship diagram of the various crystalline solid forms of Y-S-K-Y.

[0277] Figure 12A , Figure 12B , Figure 12C and Figure 12D show the representative XRPD patterns of the Y-S-K-Y in Forms A, B, C, and D, respectively.

[0278] Figure 13 shows the polymorph relationship diagram of the various crystalline solid forms of Fmoc-G-P-S-S-G-NH2.

[0279] Figure 14A , Figure 14B , Figure 14C , Figure 14D and Figure 14E respectively show the representative XRPD patterns of the Fmoc-G-P-S-S-G-NH2 pentamer in Form A, Form B, Form C, Form D, and Form E.

[0280] Figure 15A and Figure 15B respectively show the representative XRPD patterns of the Fmoc-G-P-S-S-G-OH tetramer in Form A and Form B.

[0281] Figure 16A , Figure 16B and Figure 16C respectively show the representative XRPD patterns of the GGG side chain in Form A, Form B, and Form C.

[0282] Figure 17A and Figure 17C respectively show the representative XRPD patterns of the H-A-P-P-P-S-NH2 HCl tetramer in Form A and Form B. Figure 17B shows the representative XRPD pattern of the dry form of the H-A-P-P-P-S-NH2 HCl tetramer in Form A.

[0283] Figure 18 shows the representative XRPD pattern of the H-A Fmoc-S-S-G-A-P-P-P-S-NH2 tetramer in Form A.

[0284] Figure 19 shows the LCMS analysis results of the coupling agent study.

[0285] Figure 20 shows the UPLC-MS results of the Fmoc-Y-Aib-E-G compound.

[0286] DETAILED DESCRIPTION

[0287] The present disclosure relates to crystalline forms of peptide compounds having high purity and desirable physical properties (such as hygroscopicity), and can be used for the preparation of biopharmaceutical compounds. The crystalline peptide compounds provided herein can be used to prepare biopharmaceutical peptides such as tirzepatide (SEQ ID NO:1), retatrutide (SEQ ID NO:12), and marstacimab (SEQ ID NO:16) with increased efficiency.

[0288] Formula (I)

[0289] In one aspect, the present disclosure provides a compound of formula (I), or a salt, solvate, or hydrate thereof,

[0290]

[0291] wherein R 1 is H or a protecting group; R 2 is H or a protecting group; R 3 is H or a protecting group; and R 4 is H or a protecting group.

[0292] In certain embodiments, each protecting group is independently selected from Boc, Fmoc, tert-butyl, benzyl, carboxybenzyl, methyl, allyl, cyclohexyl, and trityl groups.

[0293] In another aspect, the present disclosure provides a crystalline compound of formula (I), or a salt, solvate, or hydrate thereof,

[0294]

[0295] wherein R 1 is H or a protecting group; R 2 is H or a protecting group; R 3 is H or a protecting group; and R 4 is H or a protecting group.

[0296] In certain embodiments, R 1 is H, Fmoc, or Boc. In certain embodiments, R 2 is H or tert-butyl. In certain embodiments, R 3 is H or tert-butyl. In certain embodiments, R 4 is H or benzyl.

[0297] In certain embodiments, at least one of R 1 , R 2 , R 3 , and R 4 is a protecting group. In certain embodiments, R 1 , R 2 , R 3 , and R 4 are H.

[0298] In certain embodiments, R 3 is tert-butyl. In certain embodiments, R 3 is benzyl. In certain embodiments, R 3 is carboxybenzyl. In certain embodiments, R 3 is methyl. In certain embodiments, R 3 is allyl. In certain embodiments, R 3 is cyclohexyl. In certain embodiments, R 3 is trityl.

[0299] In certain embodiments, the crystalline form of formula (I) is Boc-l-Tyr(tBu)-Aib-Glu(OtBu)-Gly-OH having the structure of formula (I-a).

[0300]

[0301] In certain embodiments, the compound of formula (I) or (I-a) is crystalline. In certain embodiments, the compound of formula (I) or (I-a) is a solvate. In certain embodiments, the solvated compound of formula (I) or (I-a) is crystalline. In certain embodiments, the compound of formula (I) or (I-a) is a solvate derived from methyl tert-butyl ether (MTBE) or a mixture containing MTBE.

[0302] In certain embodiments, the compound of formula (I-a) is in the form of a crystalline solid characterized by a peak at a diffraction angle 2θ of 5.2°±0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 8.4°, 8.8°, 10.4°, 15.5°, 17.1° and 17.7°.

[0303] In certain embodiments, the compound of formula (I-a) is in the form of a crystalline solid characterized by a peak at a diffraction angle 2θ of 6.1°±0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 10.3°, 14.9°, 16.8°, 18.1° and 18.2°.

[0304] In certain embodiments, the compound of formula (I-a) is in the form of a crystalline solid characterized by a peak at a diffraction angle 2θ of 6.2°±0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 8.9°, 12.3°, 14.9°, 15.4° and 21.8°.

[0305] In certain embodiments, the compound of formula (I-a) is in the form of a crystalline solid characterized by peaks at diffraction angles 2θ of 5.2°, 8.4°, 8.8°, 10.4°, 15.5°, 17.1° and 17.7°±0.2 degrees in the X-ray powder diffraction pattern.

[0306] In certain embodiments, the compound of formula (I) is

[0307]

[0308] In certain embodiments, the compound of formula (I) is

[0309]

[0310] In certain embodiments, the compound of formula (I) is

[0311]

[0312] In certain embodiments, the compound of formula (I) is

[0313]

[0314] The present disclosure also provides a method for synthesizing a compound of formula (I), the method comprising: (i) reacting a compound of formula (Y prot )

[0315]

[0316] wherein R 1 and R 2 are protecting groups, with a compound of formula (Aib prot )

[0317] wherein R 5 is a protecting group, thereby forming a compound of formula (Y prot -Aib prot ),

[0318]

[0319] removing the protecting group of R 5 and forming a compound of formula (Y prot -Aib),

[0320] (ii) reacting the compound of formula (Y prot -Aib) with a compound of formula (E prot )

[0321]

[0322] wherein R 3 is a protecting group, thereby forming a compound of formula (Y prot -Aib-E prot ),

[0323]

[0324] (iii) reacting the compound of formula (Y prot -Aib-E prot ) with a compound of formula (G prot ),

[0325]

[0326] wherein R 4 is a protecting group, thereby forming a compound of formula (Y prot -Aib-E prot -G prot ).

[0327]

[0328] and optionally (iv) removing one or more of the protecting groups R 1 , R 2 , R 3 and R 4 .

[0329] In certain embodiments, R 5 is tert-butyl.

[0330] In certain embodiments, R 1 is Fmoc, R 2 is tert-butyl, R 3 is tert-butyl, R 4 is tert-butyl, and R 5 is tert-butyl.

[0331] Formula (II)

[0332] In another aspect, the present disclosure provides a compound of formula (II), or a salt, solvate or hydrate thereof

[0333]

[0334] wherein R 6 is H or a protecting group; R 7 is H or a protecting group; R 8 is H or a protecting group; R 9 is H or a protecting group; and R 10 is H or a protecting group.

[0335] In certain embodiments, each protecting group is independently selected from Boc, Fmoc, tert-butyl, benzyl, carboxybenzyl, methyl, allyl, cyclohexyl and trityl groups. In certain embodiments, the protecting group is Boc or Fmoc.

[0336] In certain embodiments, R 6 is H, Fmoc or Boc. In certain embodiments, R 7 is H or tert-butyl. In certain embodiments, R 8 is H or tert-butyl. In certain embodiments, R 9 is H or tert-butyl. In certain embodiments, R 10is H or benzyl. In certain embodiments, R 6 , R 7 , R 8 , R 9 and R 10 is at least one protecting group. In certain embodiments, R 6 , R 7 , R 8 , R 9 and R 10 is H.

[0337] In certain embodiments, formula (II) is Fmoc-Thr(tBu)-Phe-Thr(tBu)-Ser(tBu)-OH having the structure of formula (II-a)

[0338]

[0339] In certain embodiments, the compound of formula (II) or (II-a) is crystalline. In certain embodiments, the compound of formula (II) or (II-a) is a solvate. In certain embodiments, the compound of formula (II) or (II-a) is a solvate formed from a solvent comprising heptane. In certain embodiments, the solvate of the compound of formula (II) or (II-a) is crystalline.

[0340] In certain embodiments, the compound of formula (II-a) is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2θ of 7.7 - 7.9° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 5.8°, 10.0°, 10.8 - 10.9°, 11.3 - 11.4°, 12.0 - 12.1°, 12.8°, 14.2 - 14.4° and 16.8 - 17.0°.

[0341] In certain embodiments, the compound of formula (II-a) is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2θ of 7.3° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 5.1°, 5.7°, 7.6°, 9.5° and 12.4°.

[0342] In certain embodiments, the compound of formula (II-a) is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2θ of 7.8° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 8.5°, 11.5°, 12.0°, 12.8°, 14.3°, 15.5°, 20.2° and 23.3°.

[0343] In certain embodiments, the compound of formula (II-a) is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2θ of 8.2 - 8.3° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 5.9°, 7.7°, 9.2°, 10.2°, 11.3°, 13.8 - 13.9°, 15.5 - 15.7°, 17.1°, and 18.5°.

[0344] Formula (III)

[0345] In another aspect, the present disclosure provides a compound of formula (III), or a salt, solvate, or hydrate thereof,

[0346]

[0347] wherein R 11 is H or a protecting group; and R 12 is H or a protecting group.

[0348] In certain embodiments, each protecting group is independently selected from Boc, Fmoc, tert-butyl, benzyl, carboxybenzyl, methyl, allyl, cyclohexyl, and trityl groups.

[0349] In certain embodiments, R 11 is H or tert-butyl. In certain embodiments, R 12 is H or tert-butyl. In certain embodiments, at least one of R 11 and R 12 is a protecting group. In certain embodiments, R 11 and R 12 are H.

[0350] In certain embodiments, formula (III) is Pro-Ser(tBu)-Ser(tBu)-Gly-NH2 having the structure of formula (III-a).

[0351]

[0352] In certain embodiments, the compound of formula (III) or (III-a) is crystalline. In certain embodiments, the compound of formula (III) or (III-a) is a solvate. In certain embodiments, the solvated form of formula (III) or (III-a) is crystalline.

[0353] In certain embodiments, the compound of formula (III-a) is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2θ of 8.0° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 7.0°, 10.3°, 14.1°, 15.2°, 16.7°, 18.0°, 19.0°, 19.7°, 20.8°, and 21.9°.

[0354] In certain embodiments, the compound of formula (III-a) is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2θ of 9.0° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 5.7°, 9.9°, 16.2°, 17.1°, 17.9°, 18.1°, 18.4°, 18.8°, 19.9°, 20.1°, and 22.5°.

[0355] In certain embodiments, the compound of formula (III-a) is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2θ of 10.5° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 5.6°, 11.9°, 13.3°, 15.4°, 15.6°, 18.1°, 19.9°, and 21.1°.

[0356] In certain embodiments, the compound of formula (III-a) is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2θ of 10.7° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 4.9°, 14.8°, 20.3°, and 21.5°.

[0357] In certain embodiments, the compound of formula (III-a) is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2θ of 10.5° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 5.9°, 10.5°, 10.9°, 12.1°, 13.1°, 15.9°, 17.5°, 20.9°, 21.1°, and 21.9°.

[0358] In certain embodiments, the compound of formula (III-a) is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2θ of 7.8° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 11.3°, 11.5°, 15.4°, 15.6°, and 21.5°.

[0359] In certain embodiments, the compound of formula (III-a) is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2θ of 10.0° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 8.1°, 12.5°, 13.5°, 14.7°, 17.8°, 18.8°, 20.0° and 22.4°.

[0360] In certain embodiments, the compound of formula (III-a) is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2θ of 21.1° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 5.6°, 10.5°, 10.8°, 11.9°, 15.4° and 23.8°.

[0361] Formula (IV)

[0362] In another aspect, the present disclosure provides a compound of formula (IV), or a salt, solvate or hydrate thereof,

[0363]

[0364] wherein R 13 is H or a protecting group; R 13* is H or a protecting group; R 14 is H or a protecting group; and R 15 is H or a protecting group.

[0365] In certain embodiments, each protecting group is independently selected from Boc, Fmoc, tert-butyl, benzyl, carboxybenzyl, methyl, allyl, cyclohexyl and trityl groups.

[0366] In certain embodiments, R 13 is H, Fmoc or Boc. In certain embodiments, R 13* is H. In certain embodiments, R 14 is H or tert-butyl. In certain embodiments, R 15 is H or tert-butyl. In certain embodiments, R 13 , R 14 and R 15 in at least one is a protecting group. In certain embodiments, R 13 , R 13* , R 14 and R 15 are H.

[0367] In certain embodiments, formula (IV) is Gly-Pro-Ser(tBu)-Ser(tBu)-Gly-NH2 having the structure of formula (IV-a)

[0368]

[0369] In certain embodiments, the compound of formula (IV) or (IV-a) is crystalline. In certain embodiments, the compound of formula (IV) or (IV-a) is a solvate. In certain embodiments, the solvated compound of formula (IV) or (IV-a) is crystalline.

[0370] In certain embodiments, the compound of formula (IV-a) is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2θ of 5.1° ± 0.2 degrees and one or more peaks selected from 4.3°, 6.1°, 8.0°, 10.1° and 18.7° in the X-ray powder diffraction pattern.

[0371] In certain embodiments, the compound of formula (IV-a) is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2θ of 5.2° ± 0.2 degrees and one or more peaks selected from 6.0°, 6.7°, 10.0°, 10.3°, 16.4°, 17.8°, 18.3°, 19.4° and 22.4° in the X-ray powder diffraction pattern.

[0372] In certain embodiments, formula (IV) has the structure of formula (IV-b):

[0373]

[0374] wherein R 54 is H or a protecting group; R 55 is H or a protecting group; and R 56 is H or a protecting group.

[0375] In certain embodiments, the protecting group is selected from Boc, Fmoc, tert-butyl and trityl groups. In certain embodiments, R 54 is H or tert-butyl. In certain embodiments, R 55 is H or tert-butyl. In certain embodiments, R 56 is H or Boc. In certain embodiments, R 54 , R 55 and R 56 in at least one of which is H. In certain embodiments, R 54 , R 55 and R 56 in at least one of which is a protecting group.

[0376] In certain embodiments, Formula (IV) is Fmoc-Gly-Pro-Ser(tBu)-Ser(tBu)-Gly-NH2 having the structure of Formula (IV-c):

[0377]

[0378] In certain embodiments, the compound of Formula (IV-c) is a solvate.

[0379] In certain embodiments, the solvate is produced from acetone.

[0380] In certain embodiments, the compound of Formula (IV-c) is a desolvate.

[0381] In certain embodiments, the compound of Formula (IV-c) is crystalline.

[0382] In certain embodiments, the compound of Formula (IV-c) is in the form of a crystalline solid, the crystalline solid being characterized by peaks at diffraction angles 2-θ of 5.8° and 18.5° ± 0.2 degrees in an X-ray powder diffraction pattern and one or more peaks selected from 8.6°, 9.4°, 12.9°, 13.8°, 17.2° and 19.4°.

[0383] In certain embodiments, the compound of Formula (IV-c) is in the form of a crystalline solid, the crystalline solid being characterized by peaks at diffraction angles 2-θ of 7.0 - 7.1° and 7.5 - 7.7° ± 0.2 degrees in an X-ray powder diffraction pattern and one or more peaks selected from 5.3 - 5.4°, 9.7 - 9.9° and 14.7 - 14.9°.

[0384] In certain embodiments, the compound of Formula (IV-c) is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2-θ of 8.3° ± 0.2 degrees in an X-ray powder diffraction pattern and one or more peaks selected from 6.3°, 11.4°, 14.3° and 16.6°.

[0385] In certain embodiments, the compound of Formula (IV-c) is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2-θ of 7.2° ± 0.2 degrees in an X-ray powder diffraction pattern and one or more peaks selected from 6.8°, 8.6°, 15.8° and 18.9°.

[0386] In certain embodiments, the compound of formula (IV-c) is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2-θ of 6.1°±0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 6.3°, 7.8°, 10.0° and 12.4°.

[0387] The present disclosure also provides a method for synthesizing a compound of formula (IV-b), the method comprising:

[0388] (i) reacting a compound of formula (Fmoc-G) with a compound of formula (P prot ) to form a compound of formula (Fmoc-G-P prot )

[0389]

[0390] wherein R 57 is a protecting group;

[0391] (ii) removing the protecting group R 57 to form a compound of (Fmoc-G-P)

[0392]

[0393] (iii) reacting a compound of formula (Fmoc-G-P) with a compound of formula (S prot2 ) to form a compound of formula (Fmoc-G-P-S prot2 )

[0394]

[0395] wherein R 54 and R 58 are protecting groups;

[0396] (iv) removing the protecting group R 58 to form a compound of (Fmoc-G-P-S prot1 )

[0397]

[0398] (v) reacting a compound of formula (Fmoc-G-P-S prot1 ) with a compound of formula (S prot2 ) to form a compound of formula (Fmoc-G-P-S prot1 -S prot2 )

[0399]

[0400] wherein R 55 and R59 is a protecting group; and

[0401] (vi) removing the protecting group R 59 to form (Fmoc-F-G prot1 -S prot1 -S prot1 ) compound

[0402]

[0403] (vii) reacting a compound of formula (Fmoc-G-P-S prot1 -S prot1 ) with a compound of formula (G prot ) to form a compound of formula (Fmoc-G-P-S prot1 -S prot1 -G prot ) compound

[0404]

[0405] wherein R 60 is a protecting group;

[0406] (viii) converting a compound of formula (Fmoc-G-P-S prot1 -S prot1 -G prot ) into a compound of formula (IV-b)

[0407]

[0408] (ix) optionally removing one or more protecting groups R 54 , R 55 and R 56 .

[0409] In certain embodiments, the protecting group is selected from Boc, Fmoc, tert-butyl and trityl groups.

[0410] The present disclosure also provides a method for synthesizing a polypeptide of SEQ ID NO:12, the method comprising conjugating a compound of formula (IV-b) to the N-terminus of a polypeptide of SEQ ID NO:22 through its C-terminus, and conjugating a compound of formula (IV-b) to the C-terminus of a polypeptide of SEQ ID NO:23 through its N-terminus.

[0411] The present disclosure also provides a method for synthesizing a polypeptide of SEQ ID NO:24, the method comprising conjugating a compound of formula (IV-b) to the N-terminus of a polypeptide of SEQ ID NO:22 through its C-terminus.

[0412] The present disclosure also provides a method for synthesizing the polypeptide of SEQ ID NO:16, the method comprising conjugating a compound of formula (IV-b) to the C-terminus of the polypeptide of SEQ ID NO:25 through its N-terminus.

[0413] The present disclosure also provides a method for synthesizing the polypeptide of SEQ ID NO:1, the method comprising conjugating a compound of formula (IV-b) to the N-terminus of the polypeptide of SEQ ID NO:8 through its C-terminus, and conjugating a compound of formula (IV-b) to the C-terminus of the polypeptide of SEQ ID NO:9 through its N-terminus.

[0414] Formula (V)

[0415] In yet another aspect, the present disclosure provides a compound of formula (V), or a salt, solvate or hydrate thereof,

[0416]

[0417] wherein R 16 is H or a protecting group; R 17 is H or a protecting group; R 18 is H or a protecting group; R 19 is H or a protecting group; R 20 is H or a protecting group; and R 21 is H or a protecting group.

[0418] In certain embodiments, each protecting group is independently selected from Boc, Fmoc, tert-butyl, benzyl, carboxybenzyl, methyl, allyl, cyclohexyl and trityl groups.

[0419] In certain embodiments, R 16 is H, Fmoc or Boc. In certain embodiments, R 17 is H or tert-butyl. In certain embodiments, R 18 is H or tert-butyl. In certain embodiments, R 19 is H or tert-butyl. In certain embodiments, R 20 is H or tert-butyl. In certain embodiments, R 21 is H or benzyl. In certain embodiments, R 16 , R 17 , R 18 , R 19 , R 20 and R 21 is at least one protecting group. In certain embodiments, R 16 , R 17 , R 18 , R 19 , R20 and R 21 is H.

[0420] In certain embodiments, Formula (V) is Fmoc-Thr(tBu)-Phe-Thr(tBu)-Ser(tBu)-Asp(OtBu)-OH having the structure of Formula (V-a).

[0421]

[0422] In certain embodiments, the compound of Formula (V) or (V-a) is crystalline.

[0423] In certain embodiments, the compound of Formula (V-a) is in the form of a crystalline solid characterized by a peak at a diffraction angle 2θ of 5.8 - 6.1° ± 0.2 degrees and one or more peaks selected from 6.7 - 7.1° and 8.8 - 9.0° in an X-ray powder diffraction pattern.

[0424] In certain embodiments, the compound of Formula (V-a) is in the form of a crystalline solid characterized by a peak at a diffraction angle 2θ of 5.0 - 5.2° ± 0.2 degrees and one or more peaks selected from 5.3 - 5.4°, 5.7 - 6.0°, 6.1 - 6.2°, 7.6 - 7.9° and 8.7 - 9.1° in an X-ray powder diffraction pattern.

[0425] In certain embodiments, the polypeptide compounds described herein can be used to synthesize the bioactive polypeptide TZP (SEQ ID NO: 1, 39 amino acids). In certain embodiments, some of the compounds disclosed herein are conjugated to other polypeptide fragments to form full-length TZP. In certain embodiments, the crystalline compounds of the invention (such as the Y-Aib-E-G tetramer of Formula (I-a)) can be used as pure, stable, and easy-to-use intermediates for high-yield TZP synthesis. In certain embodiments, crystallization of the compounds of the invention may help remove impurities from crude materials. Compared to amorphous crude materials, the crystalline compounds may exhibit increased purity (e.g., as measured by UPLC-MS analysis). In certain embodiments, crystallization of the crude compound reduces the necessary solvent flow, thus providing a "greener", more ecologically friendly process. In certain embodiments, crystallization of a crude compound admixed with 1% dimer (an impurity) may produce a crystalline compound with almost complete removal of the dimer. In certain embodiments, crystallization also improves physical properties, e.g., hygroscopicity. In certain embodiments, compared to amorphous compounds, the crystalline compounds (such as the Y-Aib-E-G tetramer of Formula (I-a)) may exhibit a significantly reduced weight gain due to water absorption.

[0426] A variety of synthetic routes can be selected using peptide synthesis techniques known in the art. In any given synthetic route, one or more of the compounds described in the present disclosure can be employed.

[0427] In certain embodiments, a method for synthesizing the polypeptide of SEQ ID NO:1 (TZP) is disclosed, the method comprising conjugating a compound of formula (I) to the N-terminus of the polypeptide of SEQ ID NO:2 (TZP amino acids 5-39) through its C-terminus.

[0428] In certain embodiments, a method for synthesizing the polypeptide of SEQ ID NO:26 (TZP 1-14 amino acids, which is TyrXaa Glu Gly ThrPhe ThrSerAsp Tyr SerIle Xaa Leu, where Xaa is Aib) is disclosed, the method comprising conjugating a compound of formula (I) to the N-terminus of the polypeptide of SEQ ID NO:27 (TZP 5-14, which is ThrPhe ThrSer Asp Tyr SerIle Xaa Leu, where Xaa is Aib) through its C-terminus.

[0429] Formula (VI)

[0430] In another aspect, the present disclosure provides a compound of formula (VI), or a salt, solvate or hydrate thereof,

[0431]

[0432] wherein R 22 is H or a protecting group; R 23 is H or a protecting group; R 24 is H or a protecting group, and R 25 is H or a protecting group.

[0433] In certain embodiments, each protecting group is independently selected from Boc, Fmoc, tert-butyl, benzyl, carboxybenzyl, methyl, allyl, cyclohexyl and trityl groups. In certain embodiments, R 22 is H or Boc. In certain embodiments, wherein R 23 is H or tert-butyl. In certain embodiments, R 24 is H or trityl. In certain embodiments, R 25 is H or tert-butyl. In certain embodiments, at least one of R 22 , R 23 , R 24 and R 25 is H. In certain embodiments, R 22 , R 23 , R24 and R 25 is at least one protecting group.

[0434] In certain embodiments, formula (VI) is Boc-Tyr(tBu)-Aib-Gln(trt)-Gly-OH having the structure of formula (VI-a):

[0435]

[0436] In certain embodiments, the compound of formula (VI) or (VI-a) is a solvate. In certain embodiments, the compound is a solvate derived from amyl acetate, a mixture comprising amyl acetate, ethyl acetate, or a mixture comprising 2-methyltetrahydrofuran and tert-amyl methyl ether.

[0437] In certain embodiments, the mixture comprising amyl acetate is selected from the group consisting of a mixture comprising amyl acetate and tert-butyl ethyl ether, a mixture comprising amyl acetate and tert-amyl methyl ether, or a mixture comprising amyl acetate and heptane.

[0438] In certain embodiments, the compound of formula (VI) or (VI-a) is a desolvate or a partial desolvate.

[0439] In certain embodiments, the compound of formula (VI) or (VI-a) is crystalline.

[0440] In certain embodiments, the compound of formula (VI-a) is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2-θ of 6.3 - 6.4° ± 0.2 degrees in an X-ray powder diffraction pattern and one or more peaks selected from 4.5°, 7.1°, 13.0 - 13.1°, 15.9 - 16.0°, and 18.4 - 18.6°.

[0441] In certain embodiments, the compound of formula (VI-a) is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2-θ of 7.0 - 7.2° ± 0.2 degrees in an X-ray powder diffraction pattern and one or more peaks selected from 5.0 - 5.4°, 7.6 - 7.7°, 8.8 - 8.9°, 9.4 - 9.5°, and 12.5 - 12.7°.

[0442] The present disclosure also provides a method for synthesizing a compound of formula (VI), the method comprising:

[0443] (i) reacting a compound of formula (Y prot ) with a compound of formula (Aib prot ) to form a compound of formula (Y prot -Aib prot )

[0444]

[0445] wherein R 22 、R 23 and R 26 are protecting groups;

[0446] (ii) removing the protecting group R 26 to form a compound of (Y prot -Aib);

[0447]

[0448] (iii) reacting the compound of formula (Y prot -Aib) with a compound of formula (Q prot2 ) to form a compound of formula (Y prot -Aib-Q prot2 );

[0449]

[0450] wherein R 24 and R 27 are protecting groups;

[0451] (iv) removing the protecting group R 27 to form a compound of (Y prot -Aib-Q prot1 );

[0452]

[0453] (v) reacting the compound of formula (Y prot -Aib-Q prot1 ) with a compound of formula (G prot ) to form a compound of formula (VI);

[0454]

[0455] wherein R 25 is a protecting group; and

[0456] (vi) optionally removing one or more of the protecting groups R 22 、R 23 、R 24 and R 25 .

[0457] In certain embodiments, the protecting group is selected from Boc, Fmoc, tert-butyl and trityl groups.

[0458] The present disclosure further provides a method for synthesizing a polypeptide of SEQ ID NO:12, the method comprising conjugating the C-terminus of a compound of formula (VI-a) to the N-terminus of a polypeptide of SEQ ID NO:13.

[0459] The present disclosure also provides a method for synthesizing a polypeptide of SEQ ID NO:14, the method comprising conjugating the C-terminus of a compound of formula (VI-a) to the N-terminus of a polypeptide of SEQ ID NO:15.

[0460] Formula (VII)

[0461] In another aspect, the present disclosure provides a compound of formula (VII), or a salt, solvate or hydrate thereof,

[0462]

[0463] wherein R 28 is H or a protecting group; R 29 is H or a protecting group, and R 30 is H or a protecting group.

[0464] In certain embodiments, each protecting group is independently selected from Boc, Fmoc, tert-butyl, benzyl, carboxybenzyl, methyl, allyl, cyclohexyl and trityl groups. In certain embodiments, R 28 is H or Boc. In certain embodiments, R 29 is H or trityl. In certain embodiments, R 30 is H or tert-butyl. In certain embodiments, at least one of R 28 , R 29 and R 30 is H. In certain embodiments, at least one of R 28 , R 29 and R 30 is a protecting group.

[0465] In certain embodiments, formula (VII) is Boc-His(dnp)-Aib-Gln(trt)-Gly-OH having the structure of formula (VII-a):

[0466]

[0467] In certain embodiments, the compound of formula (VII) or (VII-a) is a solvate. In certain embodiments, the solvate is formed from any one of the following: a mixture of acetonitrile and methyl tert-butyl ether, a mixture of nitromethane and methyl tert-butyl ether, a mixture of tetrahydrofuran and methyl tert-butyl ether, methyl acetate, and ethyl acetate.

[0468] In certain embodiments, the compound of formula (VII) or (VII-a) is crystalline.

[0469] In certain embodiments, the compound of formula (VII) or (VII-a) is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2-θ of 4.8°±0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 5.6°, 6.2°, 14.8°, and 15.6°.

[0470] In certain embodiments, the compound of formula (VII-a) is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2-θ of 5.3°±0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 7.7°, 10.5°, 11.3°, 11.6°, and 14.4°.

[0471] In certain embodiments, the compound of formula (VII-a) is in the form of a crystalline solid, the crystalline solid being characterized by peaks at diffraction angles 2-θ of 6.2° and 6.9°±0.2 degrees in the X-ray powder diffraction pattern.

[0472] The present disclosure also provides a method for synthesizing a compound of formula (VII), the method comprising:

[0473] (i) reacting a compound of formula (H(dnp) prot ) with a compound of formula (Aib prot ) to form a compound of formula (H(dnp) prot -Aib prot )

[0474]

[0475] wherein R 28 and R 31 are protecting groups;

[0476] (ii) removing the protecting group R 31 to form a compound of (H(dnp) prot -Aib)

[0477]

[0478] (iii) reacting a compound of formula (H(dnp) prot -Aib) with a compound of formula (Q prot2 ) to form a compound of formula (H(dnp) prot -Aib-Q prot2 )

[0479]

[0480] wherein R 29 and R 32 are protecting groups;

[0481] (iv) Removing the protecting group R 32 to form the compound of (H(dnp) prot -Aib-Q prot1 )

[0482]

[0483] (v) Reacting the compound of formula (H(dnp) prot -Aib-Q prot1 ) with a compound of formula (G prot ) to form a compound of formula (VII)

[0484]

[0485] wherein R 30 is a protecting group; and

[0486] (vi) Optionally removing one or more protecting groups R 28 、R 29 and R 30 .

[0487] The present disclosure also provides a method for synthesizing the polypeptide of SEQ ID NO:16, the method comprising conjugating a compound of formula (VII) or formula (VII-a) to the N-terminus of the polypeptide of SEQ ID NO:17 through its C-terminus.

[0488] Formula (VIII)

[0489] In another aspect, the present disclosure provides a compound of formula (VIII), or a salt, solvate or hydrate thereof,

[0490]

[0491] wherein R 33 is H or a protecting group; R 34 is H or a protecting group; and R 35 is H or a protecting group.

[0492] In certain embodiments, each protecting group is independently selected from Boc, Fmoc, tert-butyl, benzyl, carboxybenzyl, methyl, allyl, cyclohexyl and trityl groups. In certain embodiments, R 33 is H or Boc. In certain embodiments, R 34is H or trityl. In certain embodiments, R 35 is H or tert-butyl. In certain embodiments, R 33 , R 34 and R 35 in at least one is H. In certain embodiments, R 33 , R 34 and R 35 in at least one is a protecting group.

[0493] In certain embodiments, formula (VIII) is Boc-His(trt)-Aib-Gln(trt)-Gly-OH having the structure of formula (VIII-a):

[0494]

[0495] In certain embodiments, the compound of formula (VIII) or (VIII-a) is a solvate. In certain embodiments, the solvate is produced by any one of the following: a mixture of tetrahydrofuran and methyl tert-butyl ether, a mixture of tetrahydrofuran and heptane, a mixture of 1,4-dioxane and water, a mixture of ethyl acetate and methyl tert-butyl ether, and a mixture of acetonitrile and methyl tert-butyl ether.

[0496] In certain embodiments, the compound of formula (VIII) or (VIII-a) is crystalline.

[0497] In certain embodiments, the compound of formula (VIII-a) is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2-θ of 4.7° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 5.5°, 8.2°, 10.1°, 11.8°, 13.3°, 13.6°, and 18.9°.

[0498] In certain embodiments, the compound of formula (VIII-a) is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2-θ of 5.8° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 5.3°, 8.9°, 9.2°, 15.2°, 18.6°, and 19.5°.

[0499] The present disclosure also provides a method for synthesizing a compound of formula (VIII), the method comprising:

[0500] (i) reacting a compound of formula (H(trt) prot ) with a compound of formula (Aib prot ) to form a compound of formula (H(trt) prot -Aib prot )

[0501]

[0502] wherein R 33 and R 36 are protecting groups;

[0503] (ii) removing the protecting group R 36 to form a compound of (H(trt) prot -Aib);

[0504]

[0505] (iii) reacting the compound of formula (H(trt) prot -Aib) with a compound of formula (Q prot2 ) to form a compound of formula (H(trt) prot -Aib-Q prot2 );

[0506]

[0507] wherein R 33 and R 37 are protecting groups;

[0508] (iv) removing the protecting group R 37 to form a compound of (H(trt) prot -Aib-Q prot1 );

[0509]

[0510] (v) reacting the compound of formula (H(trt) prot -Aib-Q prot1 ) with a compound of formula (G prot ) to form a compound of formula (VIII);

[0511]

[0512] wherein R 35 is a protecting group; and

[0513] (vi) optionally removing one or more of the protecting groups R 33 , R 34 and R 35 .

[0514] In certain embodiments, the protecting group is selected from Boc, Fmoc, tert-butyl and trityl groups.

[0515] The present disclosure also provides a method for synthesizing the polypeptide of SEQ ID NO:16, the method comprising conjugating a compound of formula (VIII-a) to the N-terminus of the polypeptide of SEQ ID NO:17 through its C-terminus.

[0516] Formula (IX)

[0517] In another aspect, the present disclosure provides a compound of formula (IX), or a salt, solvate or hydrate thereof,

[0518]

[0519] wherein R 38 is H or a protecting group; R 39 is H or a protecting group; R 40 is H or a protecting group; R 41 is H or a protecting group; R 42 is H or a protecting group; and R 43 is H or a protecting group.

[0520] In certain embodiments, each protecting group is independently selected from Boc, Fmoc, tert-butyl, benzyl, carboxybenzyl, methyl, allyl, cyclohexyl and trityl groups.

[0521] In certain embodiments, R 38 is H or Fmoc. In certain embodiments, R 39 is H or tert-butyl. In certain embodiments, R 40 is H or tert-butyl. In certain embodiments, R 41 is H or tert-butyl. In certain embodiments, R 42 is H or Boc. In certain embodiments, R 43 is H or tert-butyl. In certain embodiments, at least one of R 38 , R 39 , R 40 , R 41 , R 42 and R 43 is H. In certain embodiments, at least one of R 38 , R 39 , R 40 , R 41 , R 42 and R 43 is a protecting group.

[0522] In certain embodiments, formula (IX) is Fmoc-Asp(tBu)-Tyr(tBu)-Ser(TBu)-(TBu)Lys-OH having the structure of formula (IX-a):

[0523]

[0524] In certain embodiments, the compound of formula (IX) or (IX-a) is a solvate.

[0525] In certain embodiments, the solvate is formed from any of the following: a mixture of methyl acetate and dibutyl ether, a mixture of acetone and dibutyl ether, a mixture of acetonitrile and dibutyl ether, a mixture of ethyl acetate and dibutyl ether, a mixture of methyl acetate and heptane, and a mixture of methyl ethyl ketone and dibutyl ether.

[0526] In certain embodiments, the compound of formula (IX) or (IX-a) is a desolvate or is anhydrous.

[0527] In certain embodiments, the compound of formula (IX-a) is crystalline.

[0528] In certain embodiments, the compound of formula (IX-a) is in the form of a crystalline solid characterized by a peak at a diffraction angle 2-θ of 5.3° ± 0.2 degrees in an X-ray powder diffraction pattern and one or more peaks selected from 6.0°, 6.9°, 7.2°, 8.0°, 12.2°, and 15.6°.

[0529] In certain embodiments, the compound of formula (IX-a) is in the form of a crystalline solid characterized by a peak at a diffraction angle 2-θ of 5.8° ± 0.2 degrees in an X-ray powder diffraction pattern and one or more peaks selected from 4.4°, 6.6°, 10.1°, 11.4°, 13.4°, and 15.5°.

[0530] In certain embodiments, the compound of formula (IX-a) is in the form of a crystalline solid characterized by peaks at diffraction angles 2-θ of 4.5° and 5.5° ± 0.2 degrees in an X-ray powder diffraction pattern and one or more peaks selected from 6.0° and 7.3°.

[0531] The present disclosure also provides a method for synthesizing a compound of formula (IX), the method comprising:

[0532] (i) reacting a compound of formula (D prot ) with a compound of formula (Y prot2 ) to form a compound of formula (D prot -Y prot2 )

[0533]

[0534] wherein R 38 、R 39, R 40 and R 44 are protecting groups;

[0535] (ii) Remove the protecting group R 44 to form a compound of (D prot -Y prot1 )

[0536]

[0537] (iii) React the compound of formula (D prot -Y prot1 ) with a compound of formula (S prot2 ) to form a compound of formula (D prot -Y prot1 -S prot2 )

[0538]

[0539] wherein R 41 and R 45 are protecting groups;

[0540] (iv) Remove the protecting group R 45 to form a compound of (D prot -Y prot1 -S prot1 )

[0541]

[0542] (v) React the compound of formula (D prot -Y prot1 -S prot1 ) with a compound of formula (K prot2 ) to form a compound of formula (IX)

[0543]

[0544] wherein R 42 and R 43 are protecting groups; and

[0545] (vi) Optionally remove one or more of the protecting groups R 38 , R 39 , R 40 , R 41 , R 42 and R 43 .

[0546] In certain embodiments, the protecting groups are selected from Boc, Fmoc, tert-butyl, and trityl groups.

[0547] The present disclosure also provides a method for synthesizing the polypeptide of SEQ ID NO: 16, the method comprising conjugating a compound of formula (IX-a) to the N-terminus of a polypeptide of SEQ ID NO: 18 via its C-terminus, and conjugating a compound of formula (IX-a) to the C-terminus of a polypeptide of SEQ ID NO: 19 via its N-terminus.

[0548] Formula (X)

[0549] In another aspect, the present disclosure provides a compound of formula (X), or a salt, solvate or hydrate thereof,

[0550]

[0551] Where R 46 is H or a protecting group; R 47 is H or a protecting group; R 48 is H or a protecting group; R 49 is H or a protecting group; R 50 is H or a protecting group; and R 51 is H or a protecting group.

[0552] In certain embodiments, each protecting group is independently selected from Boc, Fmoc, tert-butyl, benzyl, carboxybenzyl, methyl, allyl, cyclohexyl, and trityl groups.

[0553] In certain embodiments, R 46 is H or tert-butyl. In certain embodiments, R 47 is H or tert-butyl. In certain embodiments, R 48 is H or Boc. In certain embodiments, R 49 is H or Fmoc. In certain embodiments, R 50 is H or tert-butyl. In certain embodiments, R 51 is H or tert-butyl. In certain embodiments, R 46 , R 47 , R 48 , R 49 , R 50 and R 51 At least one of is H. In certain embodiments, R 46 , R 47 , R 48 , R 49 , R 50 and R 51 At least one of the groups is a protecting group.

[0554] In certain embodiments, Formula (X) is Fmoc-Tyr(tBu)-Ser(tBu)-Lys(Boc)-(tBu)Tyr-OH having the structure of Formula (X-a):

[0555]

[0556] In certain embodiments, the compound of Formula (X) or (X-a) is a solvate.

[0557] In certain embodiments, the solvate is formed from ethanol or isopropanol.

[0558] In certain embodiments, the compound of Formula (X) or (X-a) is a desolvate.

[0559] In certain embodiments, the compound of Formula (X) or (X-a) is crystalline.

[0560] In certain embodiments, the compound of Formula (X-a) is in the form of a crystalline solid, the crystalline solid being characterized by peaks at diffraction angles 2-θ of 18.1° and 18.7° ± 0.2 degrees in an X-ray powder diffraction pattern and one or more peaks selected from 5.7°, 8.7°, 13.7°, 14.3°, 15.9°, and 16.2°.

[0561] In certain embodiments, the compound of Formula (X-a) is in the form of a crystalline solid, the crystalline solid being characterized by peaks at diffraction angles 2-θ of 5.9° and 10.5° ± 0.2 degrees in an X-ray powder diffraction pattern and one or more peaks selected from 7.1°, 8.9°, 14.6°, and 16.6°.

[0562] In certain embodiments, the compound of Formula (X-a) is in the form of a crystalline solid, the crystalline solid being characterized by peaks at diffraction angles 2-θ of 7.8° and 20.3° ± 0.2 degrees in an X-ray powder diffraction pattern and one or more peaks selected from 5.8°, 15.5°, and 19.5°.

[0563] In certain embodiments, the compound of Formula (X-a) is in the form of a crystalline solid, the crystalline solid being characterized by peaks at diffraction angles 2-θ of 5.9° and 7.4° ± 0.2 degrees in an X-ray powder diffraction pattern and one or more peaks selected from 6.5°, 6.9°, and 14.8°.

[0564] The present disclosure also provides a method for synthesizing a compound of Formula (X), the method comprising:

[0565] (i) reacting a compound of Formula (Y prot ) with a compound of Formula (S prot2) The compound reacts to form a compound of formula (Y prot -S prot2 )

[0566]

[0567] wherein R 46 、R 47 、R 48 and R 52 are protecting groups;

[0568] (ii) Remove the protecting group R 52 to form a compound of (Y prot -S prot1 )

[0569]

[0570] (iii) React the compound of formula (Y prot -S prot1 ) with a compound of formula (K prot2 ) to form a compound of formula (Y prot -S prot1 -K prot2 )

[0571]

[0572] wherein R 49 and R 53 are protecting groups;

[0573] (iv) Remove the protecting group R 53 to form a compound of (Y prot -S prot1 -K prot1 )

[0574]

[0575] (v) React the compound of formula (Y prot -S prot1 -K prot1 ) with a compound of formula (Y prot2 ) to form a compound of formula (X)

[0576]

[0577] wherein R 50 and R 51 are protecting groups; and

[0578] (vi) Optionally remove one or more protecting groups R 46 、R 47 、R 48, R 49 , R 50 and R 51 .

[0579] In certain embodiments, the protecting group is selected from Boc, Fmoc, tert-butyl, and trityl groups.

[0580] The present disclosure also provides a method for synthesizing the polypeptide of SEQ ID NO:16, the method comprising conjugating a compound of formula (X-a) to the N-terminus of the polypeptide of SEQ ID NO:20 through its C-terminus, and conjugating a compound of formula (X-a) to the C-terminus of the polypeptide of SEQ ID NO:21 through its N-terminus.

[0581] Formula (XI)

[0582] In another aspect, the present disclosure provides a compound of formula (XI), or a salt, solvate, or hydrate thereof,

[0583]

[0584] wherein R 64 is H or a protecting group; R 65 is H or a protecting group; and R 66 is H or a protecting group. In certain embodiments, R 64 and R 65 are protecting groups; and R 66 is H or a protecting group. In certain embodiments, R 64 and R 65 are protecting groups; and R 66 is H.

[0585] In certain embodiments, each protecting group is independently selected from Boc, Fmoc, tert-butyl, benzyl, carboxybenzyl, methyl, allyl, cyclohexyl, and trityl groups.

[0586] In certain embodiments, formula (XI) is Fmoc-Gly-Pro-Ser(tBu)-Ser(tBu)-Gly-OH having the structure of formula (XI-a):

[0587]

[0588] In certain embodiments, the compound of formula (XI-a) is crystalline.

[0589] In certain embodiments, the compound of formula (XI-a) is in the form of a crystalline solid, the crystalline solid being characterized by peaks at diffraction angles 2-θ of 6.1° and 8.5° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 5.8°, 16.9°, 18.5°, 18.8°, 19.3° and 20.9°.

[0590] Formula (XII)

[0591] In another aspect, the present disclosure provides a compound of formula (XII), or a salt, solvate or hydrate thereof,

[0592]

[0593] wherein R 61 is H or a protecting group; R 62 is H or a protecting group; and R 63 is H or a protecting group.

[0594] In certain embodiments, each protecting group is independently selected from Boc, Fmoc, tert-butyl, carboxybenzyl, methyl, allyl, cyclohexyl and trityl groups. In certain embodiments, R 61 is H or tert-butyl. In certain embodiments, R 62 is H or tert-butyl. In certain embodiments, R 63 is H or tert-butyl. In certain embodiments, R 61 , R 62 and R 63 at least one of which is H. In certain embodiments, R 61 , R 62 and R 63 at least one of which is a protecting group.

[0595] In certain embodiments, formula (XII) is a GGG side chain having the structure of formula (XII-a):

[0596]

[0597] In certain embodiments, the compound of formula (XII) or (XII-a) is a desolvate or is anhydrous.

[0598] In certain embodiments, the compound of formula (XII) or (XII-a) is crystalline.

[0599] In certain embodiments, the compound of formula (XII-a) is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2-θ of 11.4° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 6.0°, 8.9°, 12.7°, 13.6°, 14.6°, 17.0° and 18.8°.

[0600] In certain embodiments, the compound of formula (XII-a) is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2-θ of 10.6° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 7.1°, 12.1°, 13.6°, 14.2°, 15.2°, 16.0° and 16.8°.

[0601] In certain embodiments, the compound of formula (XII-a) is in the form of a crystalline solid, the crystalline solid being characterized by peaks at diffraction angles 2-θ of 10.1° and 15.5° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 6.1°, 8.7°, 11.4°, 16.6° and 19.2°.

[0602] Formula (XIII)

[0603] In another aspect, the present disclosure provides a compound of formula (XIII), or a salt, solvate or hydrate thereof,

[0604]

[0605] wherein R 67 is H or a protecting group; R 68 is H or a protecting group; and R 69 is H or a protecting group.

[0606] In certain embodiments, each protecting group is independently selected from Boc, Fmoc, tert-butyl, carboxybenzyl, methyl, allyl, cyclohexyl and trityl groups.

[0607] In certain embodiments, R 67 is H or tert-butyl. In certain embodiments, R 68 is H or tert-butyl. In certain embodiments, R 69 is H or tert-butyl. In certain embodiments, R 67 , R 68 and R 69 in at least one is H. In certain embodiments, R 67 , R 68 and R 69 in at least one is a protecting group. In certain embodiments, R67 and R 69 is H, and R 68 is a protecting group.

[0608] In certain embodiments, formula (XIII) is H-Ala-Pro-Pro-Pro-Ser(tBu)-NH2 (H-A-P-P-P-S-NH2) having the structure of formula (XIII-a):

[0609]

[0610] In certain embodiments, the compound of formula (XIII) or (XIII-a) is a desolvate or is anhydrous.

[0611] In certain embodiments, the compound of formula (XIII) or (XIII-a) is crystalline.

[0612] In certain embodiments, the compound of formula (XIII-a) is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2-θ of 5.0° ± 0.2 degrees and one or more peaks selected from 8.3, 9.7 and 11.2°.

[0613] In certain embodiments, the compound of formula (XIII-a) is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2-θ of 7.2° ± 0.2 degrees and one or more peaks selected from 5.3, 8.1, 14.4 and 16.2°.

[0614] Formula (XIV)

[0615] In another aspect, the present disclosure provides a compound of formula (XIV), or a salt, solvate or hydrate thereof,

[0616]

[0617] wherein R 70 is H or a protecting group; R 71 is H or a protecting group; R 72 is H or a protecting group; R 73 is H or a protecting group; and R 74 is H or a protecting group.

[0618] In certain embodiments, each protecting group is independently selected from Boc, Fmoc, tert-butyl, carboxybenzyl, methyl, allyl, cyclohexyl and trityl groups.

[0619] In certain embodiments, R 70is H, Fmoc or tert-butyl. In certain embodiments, R 71 is H or tert-butyl. In certain embodiments, R 72 is H or tert-butyl. In certain embodiments, R 73 is H or tert-butyl. In certain embodiments, R 74 is H, Fmoc or tert-butyl. In certain embodiments, R 70 , R 71 , R 72 , R 73 and R 74 is at least one of H. In certain embodiments, R 70 , R 71 , R 72 , R 73 and R 74 is at least one of a protecting group. In certain embodiments, R 71 , R 72 and R 73 are tert-butyl. In certain embodiments, R 74 is H. In certain embodiments, R 70 is Fmoc.

[0620] In certain embodiments, formula (XIV) is Fmoc-Ser(tBu)-Ser(tBu)-Gly-Ala-Pro-Pro-Pro-Ser(tBu)-NH2 (Fmoc-S-S-G-A-P-P-P-S-NH2) having the structure of formula (XIV-a):

[0621]

[0622] In certain embodiments, the compound of formula (XIV) or (XIV-a) is a desolvate or is anhydrous.

[0623] In certain embodiments, the compound of formula (XIV) or (XIV-a) is crystalline.

[0624] In certain embodiments, the compound of formula (XIV-a) is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2-θ of 7.5° ± 0.2 degrees and one or more peaks selected from 6.1, 8.7, 10.6, 15.0, 16.1 and 18.6°.

[0625] Use

[0626] In certain embodiments, polypeptide compounds as described herein can be used to synthesize the bioactive polypeptide GGG (SEQ ID NO: 12, 39 amino acids). In certain embodiments, some of the compounds disclosed herein are conjugated to other polypeptide fragments to form full-length GGG. In certain embodiments, the crystalline compounds of the invention (such as the Y-Aib-Q-G tetramer of formula (VI-a) and the Fmoc-G-P-S-S-G-NH2 pentamer of formula (XI-a)) can be used as pure, stable, and easy-to-use intermediates for high-yield GGG synthesis. In certain embodiments, crystallization of the compounds of the invention may help remove impurities from the crude material. The crystalline compounds may exhibit improved purity (e.g., as measured by UPLC-MS analysis) compared to the amorphous crude material. In certain embodiments, crystallization of the crude compound reduces the necessary solvent flow, thus providing a "greener", more ecologically compliant process. In certain embodiments, crystallization of a crude compound doped with 1% dimer (an impurity) may produce a crystalline compound with almost complete removal of the dimer. In certain embodiments, crystallization also improves physical properties, e.g., hygroscopicity. In certain embodiments, the crystalline compounds (such as the Y-Aib-Q-G tetramer of formula (VI-a) and the Fmoc-G-P-S-S-G-NH2 pentamer of formula (XI-a)) may exhibit significantly reduced weight gain due to water absorption compared to the amorphous compounds.

[0627] In certain embodiments, polypeptide compounds as described herein can be used to synthesize the bioactive polypeptide OXM (SEQ ID NO: 16, 34 amino acids). In certain embodiments, some of the compounds disclosed herein are conjugated to other polypeptide fragments to form full-length OXM. In certain embodiments, the crystalline compounds of the present invention (such as the H(dnp)-Aib-Q-G tetramer of formula (VII-a), the H(trt)-Aib-Q-G tetramer of formula (VIII-a), the D-Y-S-K tetramer of formula (IX-a), the Y-S-K-Y tetramer of formula (X-a), and the Fmoc-G-P-S-S-G-NH2 pentamer of formula (XI-a)) can be used as pure, stable, and easy-to-use intermediates for high-yield OXM synthesis. In certain embodiments, the crystallization of the compounds of the present invention may help to remove impurities from crude materials. The crystalline compounds may exhibit improved purity (e.g., as measured by UPLC-MS analysis) compared to amorphous crude materials. In certain embodiments, the crystallization of the crude compounds reduces the necessary solvent flow, thereby providing a "greener", more environmentally friendly process. In certain embodiments, the crystallization of a crude compound doped with 1% dimer (impurity) may produce a crystalline compound with almost complete removal of the dimer. In certain embodiments, crystallization also improves physical properties, e.g., hygroscopicity. In certain embodiments, the crystalline compounds (such as the H(dnp)-Aib-Q-G tetramer of formula (VII-a), the H(trt)-Aib-Q-G tetramer of formula (VIII-a), the D-Y-S-K tetramer of formula (IX-a), the Y-S-K-Y tetramer of formula (X-a), and the Fmoc-G-P-S-S-G-NH2 pentamer of formula (XI-a)) may exhibit significantly reduced weight gain due to water absorption compared to amorphous compounds.

[0628] In certain embodiments, the compounds of formula (I), (II), (III), (IV), (V), (VI), (VII), (VIII), (IX), (X), (XI) and (XII) contain one or more protecting groups. In certain embodiments, the one or more protecting groups are selected from Fmoc, Boc, tert-butyl, benzyl, carboxybenzyl, methyl, allyl, cyclohexyl and trityl groups or combinations thereof. In certain embodiments, the one or more protecting groups are Fmoc. In certain embodiments, the one or more protecting groups are Boc. In certain embodiments, the one or more protecting groups are tert-butyl. In certain embodiments, the one or more protecting groups are trityl. In certain embodiments, the one or more protecting groups are benzyl. In certain embodiments, the one or more protecting groups are carboxybenzyl. In certain embodiments, the one or more protecting groups are methyl. In certain embodiments, the one or more protecting groups are allyl. In certain embodiments, the one or more protecting groups are cyclohexyl. In certain embodiments, the compound is protected by Fmoc, Boc, tert-butyl, benzyl, carboxybenzyl, methyl, allyl, cyclohexyl and trityl groups. In certain embodiments, the compound is protected by Fmoc group. In certain embodiments, the compound is protected by Fmoc and Boc groups. In certain embodiments, the compound is protected by Fmoc and tert-butyl groups. In certain embodiments, the compound is protected by Fmoc and trityl groups. In certain embodiments, the compound is protected by Fmoc and benzyl groups. In certain embodiments, the compound is protected by Boc group. In certain embodiments, the compound is protected by Boc and tert-butyl groups. In certain embodiments, the compound is protected by Boc and trityl groups. In certain embodiments, the compound is protected by Boc and benzyl groups. In certain embodiments, the compound is protected by tert-butyl group. In certain embodiments, the compound is protected by tert-butyl and trityl groups. In certain embodiments, the compound is protected by tert-butyl and benzyl groups. In certain embodiments, the compound is protected by trityl group. In certain embodiments, the compound is protected by trityl and benzyl groups. In certain embodiments, the compound is protected by benzyl group. In certain embodiments, the compound is protected by Fmoc, Boc and tert-butyl groups. In certain embodiments, the compound is protected by Fmoc, Boc and trityl groups. In certain embodiments, the compound is protected by Fmoc, Boc and benzyl groups. In certain embodiments, the compound is protected by Fmoc, tert-butyl and trityl groups. In certain embodiments, the compound is protected by Fmoc, tert-butyl and benzyl groups.In certain embodiments, the compound is protected by Fmoc, trityl, and benzyl groups. In certain embodiments, the compound is protected by Boc, tert-butyl, and trityl groups. In certain embodiments, the compound is protected by Boc, tert-butyl, and benzyl groups. In certain embodiments, the compound is protected by Fmoc, tert-butyl, and trityl groups.

[0629] The following abbreviations used herein have the meanings set forth herein: "API" means active pharmaceutical ingredient, "DCM" means dichloromethane, "DIC" means diisopropylcarbodiimide, "Oxyma" means ethyl cyanooxymate, "DTT" means dithiothreitol, "Fmoc" means fluorenylmethyloxycarbonyl chloride, "GGG" means retatrutide, "IPA" means isopropyl alcohol, "MTBE" means methyl tert-butyl ether, "OXM" means exenatide mecasermin, "Pip" means piperidine, "PyBOP" means (benzotriazol-1-yloxy)tris(pyrrolidino)phosphonium hexafluorophosphate, "SPPS" means solid phase peptide synthesis, "TFA" means trifluoroacetic acid, "TNTU" means 2-(5-norbornene-2,3-dicarboximido)-1,1,3,3-tetramethyluronium tetrafluoroborate, "TZP" means tizepatide, and "UPLC" means ultra performance liquid chromatography.

[0630] In certain embodiments, amino acid single letter abbreviations are printed in bold to distinguish from single letter amino acid abbreviations, while atoms are in non-bold text. In certain embodiments, amino acids are represented by their three letter abbreviations. As used herein, when an amino acid abbreviation appears with a number above the amino acid, the number represents the corresponding amino acid position in the final product. The numbers are provided for convenience, and the presence or absence of such numbers in a sequence does not affect the amino acid sequence or peptide indicated in such sequence.

[0631] The term "protect" as used herein means that a protecting group is attached at a specified position.

[0632] The term "crystalline" as used herein includes all crystalline forms having a discernible X-ray pattern.

[0633] "Amino acid" as used herein refers to naturally occurring and non-naturally occurring synthetic amino acids, as well as amino acid analogs and amino acid mimetics that act in a manner similar to naturally occurring amino acids. Naturally occurring amino acids are those encoded by the genetic code. Amino acids may be represented herein by their commonly known three letter symbols or by the single letter symbols recommended by the IUPAC-IUB Biochemical Nomenclature Commission. Amino acids include side chains and polypeptide backbone moieties.

[0634] "Peptide" or "polypeptide" refers to a contiguous sequence of two or more amino acids linked by peptide bonds. The polypeptide may be natural, synthetic, or a modification or combination of natural and synthetic.

[0635] As used herein, the term "protecting group" or "amino acid protecting group" refers to a group that protects the acid or amine moiety of an amino acid or a reactive moiety on the side chain of an amino acid. The "acid moiety" includes, for example, a carboxylic acid group (-COOH). The "amine moiety" includes, for example, a primary amine group (-NH2), a secondary amine group (-NH-), an amide group (-C(O)-NH2), and a guanidino group ([-NHC(NH2)-NH2] + ). The acid moiety or amine moiety may be part of a terminal amino acid in a peptide or polypeptide, or part of the side chain of a non-terminal amino acid in a peptide or polypeptide. Other reactive moieties on the amino acid side chain include, for example, a hydroxyl group (-OH) and a thiol group (-SH).

[0636] A protecting group may be a removable group that is known in the art to (i) protect a reactive group (such as an amine group or a carboxylic acid group) from undergoing an undesired reaction during a synthetic procedure, e.g., blocking or protecting the functionality of the reactive group while performing a reaction involving other functional sites of a compound, and (ii) be selectively deprotected in a multiple protection structure without affecting other protecting groups. Suitable protecting groups and methods for introducing and removing such groups include those known in the art, such as those described in the following: T.W. Green and P.G.M. Wuts, Greene’s Protective Groups in Organic Synthesis, John Wiley and Sons, 2007, and Isidro-Llobet et al., Amino Acid-Protecting Groups, Chem. Rev, 2009, 109(6), 2455-2504, which are incorporated herein by reference in their entirety.

[0637] Suitable protecting groups for aspartic acid (Asp) include, but are not limited to, tert-butyl (t-Bu), 3-methyl-3-pentyl (mpe), allyl, and 4-{N-[1-(4,4-dimethyl-2,6-dioxocyclohexyl)-3-methylbutyl]amino}benzyl (DMAB). In certain embodiments, the protecting group for aspartic acid (Asp) is t-Bu or mpe.

[0638] Suitable protecting groups for serine (Ser), threonine (Thr) or tyrosine (Tyr) include, but are not limited to, t-Bu and triphenylmethyl (trityl or trt). In certain embodiments, the protecting group for serine (Ser), threonine (Thr) or tyrosine (Tyr) is t-Bu or TRT.

[0639] Suitable protecting groups for glutamic acid (Glu) include, but are not limited to, t-Bu, trt, allyl and DMAB. In certain embodiments, the protecting group for glutamic acid (Glu) is t-Bu or trt.

[0640] Suitable protecting groups for glutamine (Gln) include, but are not limited to, trt, 4-methoxytrityl (4-methyltrityl or MTT), acetamidomethyl (ACM) and trimethoxybenzyl (TMOB). In certain embodiments, the protecting group for glutamine (Gln) is TRT.

[0641] Suitable protecting groups for lysine (Lys) include, but are not limited to, tert-butoxycarbonyl (Boc), allyloxycarbonyl (Alloc), 4-phenylacetoxybenzyloxycarbonyl (PhAc), MTT, 1-(4,4-dimethyl-2,6-dioxocyclohex-1-yl)ethyl (ivDde) and 2-(4,4-dimethyl-2,6-dioxocyclohexyl)ethyl (Dde). In certain embodiments, the protecting group for lysine (Lys) is Boc, MTT or Alloc.

[0642] Suitable protecting groups for tryptophan (Trp) include, but are not limited to, Boc and formyl. In certain embodiments, the protecting group for tryptophan (Trp) is Boc.

[0643] Suitable protecting groups for histidine (His) include, but are not limited to, Boc, trt and 2,4-dinitrophenyl (dnp). In certain embodiments, the protecting group for histidine (His) is Boc, trt or dnp.

[0644] Exemplary acid protecting groups include esters such as substituted and unsubstituted C1-C8 lower alkyl groups (e.g., methyl, ethyl, tert-butyl), methoxymethyl, methylthiomethyl, 2,2,2-trichloroethyl, tetrahydropyranyl, substituted and unsubstituted phenylalkyl groups (e.g., benzyl) and their substituted derivatives (e.g., alkoxybenzyl, nitrobenzyl), cinnamyl, dialkylaminoalkyl groups (e.g., dimethylaminoethyl), trimethylsilyl, substituted and unsubstituted amides and hydrazides (e.g., amides and hydrazides of N,N-dimethylamine), 7-nitroindole, hydrazine, N-phenylhydrazine, acyloxyalkyl groups (e.g., pivaloyloxymethyl, propionyloxymethyl), aromatic acyloxyalkyl groups (e.g., benzoyloxyethyl), alkoxycarbonylalkyl groups (e.g., methoxycarbonylmethyl), cyclohexyloxycarbonylmethyl, alkoxycarbonyloxyalkyl groups (e.g., tert-butoxycarbonyloxymethyl), alkoxycarbonylaminoalkyl groups (e.g., tert-butoxycarbonylaminomethyl), alkylaminocarbonylaminoalkyl groups (e.g., methylaminocarbonylaminomethyl), acylaminoalkyl groups (e.g., acetylaminomethyl), heterocyclic carbonyloxyalkyl groups (e.g., 4-methylpiperazinyl-carbonyloxymethyl), dialkylaminocarbonylalkyl groups (e.g., dimethylaminocarbonyl-methyl), (5-(lower alkyl)-2-oxo-1,3-dioxol-4-yl)alkyl groups (e.g., (5-tert-butyl-2-oxo-1,3-dioxol-4-yl)methyl) and (5-phenyl-2-oxo-1,3-dioxol-4-yl)alkyl groups (e.g., (5-phenyl-2-oxo-1,3-dioxol-4-yl)methyl).

[0645] Exemplary amine and / or amide protecting groups include, but are not limited to, acyl groups (e.g., formyl, acetyl, chloroacetyl, trichloroacetyl, o-nitrophenylacetyl, o-nitrophenoxy-acetyl, trifluoroacetyl, acetoacetyl, 4-chlorobutyryl, isobutyryl, o-nitrocinnamoyl, picolinoyl, acyl isothiocyanate, aminohexanoyl, benzoyl), acyloxy groups (e.g., methoxy-carbonyl, 9-fluorenylmethoxycarbonyl, 2,2,2-trifluoroethoxycarbonyl, 2-trimethylsilylethoxy-carbonyl, vinyloxycarbonyl, allyloxycarbonyl, tert-butoxycarbonyl (Boc), 1,1-dimethyl-propynyloxycarbonyl, benzyloxycarbonyl (Cbz), p-nitrobenzyloxycarbonyl, 2,4-dichloro-benzyloxycarbonyl), 9-xanthenyl, and trityl. Additional exemplary amide protecting groups include, but are not limited to, o-nitrocinnamoyl, picolinoyl, aminohexanoyl, benzoyl, acyloxy groups (e.g., methoxy-carbonyl, 9-fluorenylmethoxycarbonyl, 2,2,2-trifluoroethoxycarbonyl, 2-trimethylsilylethoxy-carbonyl, vinyloxycarbonyl, allyloxycarbonyl, tert-butoxycarbonyl (Boc), 1,1-dimethyl-propynyloxycarbonyl, benzyloxycarbonyl (Cbz), p-nitrobenzyloxycarbonyl, and 2,4-dichloro-benzyloxycarbonyl). Exemplary indole protecting groups include, but are not limited to, formyl (For) and tert-butoxycarbonyl (Boc). Exemplary imidazole protecting groups include, but are not limited to, tosyl (Tos), benzyloxymethyl (Bom), trityl (Trt), and tert-butoxycarbonyl (Boc). Exemplary guanidinium protecting groups include, but are not limited to, 2,2,4,6,7-pentamethyl-2,3-dihydrobenzofuran-5-sulfonyl (Pbf) and tert-butoxycarbonyl (Boc).

[0646] Exemplary hydroxy protecting groups include, but are not limited to, unsubstituted or substituted alkyl groups (e.g., tert-butyl, allyl, benzyl, methoxymethyl, tetrahydropyranyl, o-nitrobenzyl), silyl groups (e.g., tert-butyldimethylsilyl (TBDMS), tert-butyldiphenylsilyl (TBDPS)), acyl groups (e.g., acetyl, benzoyl, pivaloyl). Exemplary thiol protecting groups include, but are not limited to, p-methylbenzyl (Meb), acetamidomethyl (Acm), and trityl (Trt).

[0647] Enumerated embodiments

[0648] Embodiment 1. A compound of formula (I), or a salt, solvate or hydrate thereof,

[0649]

[0650] wherein R 1 is H or a protecting group; R2 is H or a protecting group; R 3 is H or a protecting group; and R 4 is H or a protecting group; and wherein R 1 、R 2 、R 3 and R 4 and at least one of R

[0651] Embodiment 2. The compound of Embodiment 1, wherein R 1 is H, Fmoc or Boc.

[0652] Embodiment 3. The compound of any one of Embodiments 1-2, wherein R 2 is H or tert-butyl.

[0653] Embodiment 4. The compound of any one of Embodiments 1-3, wherein R 4 is H or benzyl.

[0654] Embodiment 5. The compound of any one of Embodiments 1-4, wherein R 3 is H, tert-butyl, benzyl, carboxybenzyl, methyl, allyl, cyclohexyl or trityl.

[0655] Embodiment 6. The compound of any one of Embodiments 1-5, wherein at least two of R 1 、R 2 、R 3 and R 4 are H.

[0656] Embodiment 7. The compound of any one of Embodiments 1-6, wherein at least two of R 1 、R 2 、R 3 and R 4 are protecting groups.

[0657] Embodiment 8. The compound of Embodiment 1, wherein the compound is of the formula:

[0658]

[0659] Embodiment 9. The compound of Embodiment 1, wherein the compound is of the formula:

[0660]

[0661] Embodiment 10. The compound of Embodiment 1, wherein the compound is of the formula:

[0662]

[0663] Embodiment 11. The compound of Embodiment 1, wherein the compound is of the formula:

[0664]

[0665] Embodiment 12. The compound of Embodiment 1, wherein the compound is of the formula:

[0666]

[0667] Embodiment 13. The compound of any one of Embodiments 1-12, wherein the compound is a solvate.

[0668] Embodiment 14. The compound of Embodiment 13, wherein the solvate is produced from methyl tert-butyl ether (MTBE) or a mixture comprising MTBE.

[0669] Embodiment 15. The compound of any one of Embodiments 1-12, wherein the compound is crystalline.

[0670] Embodiment 16. The compound of Embodiment 15, wherein the compound is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2θ of 5.2° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 8.4°, 8.8°, 10.4°, 15.5°, 17.1°, and 17.7°.

[0671] Embodiment 17. The compound of Embodiment 15, wherein the compound is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2θ of 6.1° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 10.3°, 14.9°, 16.8°, 18.1°, and 18.2°.

[0672] Embodiment 18. The compound of Embodiment 15, wherein the compound is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2θ of 6.2° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 8.9°, 12.3°, 14.9°, 15.4°, and 21.8°.

[0673] Embodiment 19. A method for synthesizing the compound of Embodiment 1, the method comprising: - reacting a compound of formula (Y prot )

[0674]

[0675] wherein R 1 and R 2 are protecting groups, with a compound of formula (Aib prot) with a compound

[0676] wherein R 5 is a protecting group, thereby forming a compound of formula (Y prot -Aib prot ).

[0677]

[0678] - Remove the protecting group of R 5 and form a compound of formula (Y prot -Aib).

[0679] - React the compound of formula (Y prot -Aib) with a compound of formula (E prot ).

[0680] wherein R 3 is a protecting group, thereby forming a compound of formula (Y prot -Aib-E prot ).

[0681]

[0682] - React the compound of formula (Y prot -Aib-E prot ) with a compound of formula (G prot ).

[0683]

[0684] wherein R 4 is a protecting group, thereby forming a compound of formula (Y prot -Aib-E prot -G prot ).

[0685] and optionally

[0686] - Remove one or more of the protecting groups R 1 , R 2 , R 3 and R 4 .

[0687] Embodiment 20. A method for synthesizing a polypeptide of SEQ ID NO:1, the method comprising conjugating a compound of any one of Embodiments 1-12 to the N-terminus of a polypeptide of SEQ ID NO:2 through the C-terminus of the compound.

[0688] Embodiment 21. A method for synthesizing a polypeptide of SEQ ID NO: 26, the method comprising conjugating a compound of any one of Embodiments 1-12 to the N-terminus of a polypeptide of SEQ ID NO: 27 through the C-terminus of the compound.

[0689] Embodiment 22. A compound of formula (II), or a salt, solvate or hydrate thereof,

[0690]

[0691] wherein R 6 is H or a protecting group; R 7 is H or a protecting group; R 8 is H or a protecting group; R 9 is H or a protecting group; and R 10 is H or a protecting group.

[0692] Embodiment 23. The compound of Embodiment 22, wherein each protecting group is independently selected from Boc, Fmoc, tert-butyl and trityl groups.

[0693] Embodiment 24. The compound of any one of Embodiments 22-23, wherein R 6 is H, Fmoc or Boc.

[0694] Embodiment 25. The compound of any one of Embodiments 22-24, wherein R 7 is H or tert-butyl.

[0695] Embodiment 26. The compound of any one of Embodiments 22-25, wherein R 8 is H or tert-butyl.

[0696] Embodiment 27. The compound of any one of Embodiments 22-26, wherein R 9 is H or tert-butyl.

[0697] Embodiment 28. The compound of any one of Embodiments 22-27, wherein R 10 is H or benzyl.

[0698] Embodiment 29. The compound of any one of Embodiments 22-28, wherein at least one of R 6 , R 7 , R 8 , R 9 and R 10 is a protecting group.

[0699] Embodiment 30. The compound of any one of Embodiments 22-29, wherein R 6 , R 7 , R8 , R 9 and R 10 is H.

[0700] Embodiment 31. A compound according to Embodiment 22, wherein the compound has the formula:

[0701]

[0702] Embodiment 32. A compound according to any one of Embodiments 22 - 31, wherein the compound is a solvate.

[0703] Embodiment 33. A compound according to Embodiment 32, wherein the solvate is produced by a solvent comprising heptane.

[0704] Embodiment 34. A compound according to any one of Embodiments 22 - 31, wherein the compound is crystalline.

[0705] Embodiment 35. A compound according to Embodiment 34, wherein the compound is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2θ of 7.7 - 7.9° ± 0.2 degrees in an X - ray powder diffraction pattern and one or more peaks selected from 5.8°, 10.0°, 10.8 - 10.9°, 11.3 - 11.4°, 12.0 - 12.1°, 12.8°, 14.2 - 14.4° and 16.8 - 17.0°.

[0706] Embodiment 36. A compound according to Embodiment 34, wherein the compound is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2θ of 7.3° ± 0.2 degrees in an X - ray powder diffraction pattern and one or more peaks selected from 5.1°, 5.7°, 7.6°, 9.5° and 12.4°.

[0707] Embodiment 37. A compound according to Embodiment 34, wherein the compound is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2θ of 7.8° ± 0.2 degrees in an X - ray powder diffraction pattern and one or more peaks selected from 8.5°, 11.5°, 12.0°, 12.8°, 14.3°, 15.5°, 20.2° and 23.3°.

[0708] Embodiment 38. A compound according to Embodiment 34, wherein the compound is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2θ of 8.2 - 8.3° ± 0.2 degrees in an X - ray powder diffraction pattern and one or more peaks selected from 5.9°, 7.7°, 9.2°, 10.2°, 11.3°, 13.8 - 13.9°, 15.5 - 15.7°, 17.1° and 18.5°.

[0709] Embodiment 39. A method for synthesizing a polypeptide of SEQ ID NO:1, the method comprising (i) conjugating a compound of any one of Embodiments 22-31 through the N-terminus of the compound to the C-terminus of a polypeptide of SEQ ID NO:3 to form a polypeptide of SEQ ID NO:4; and (ii) conjugating the polypeptide of SEQ ID NO:4 through its C-terminus to the N-terminus of a polypeptide of SEQ ID NO:5.

[0710] Embodiment 40. A compound of formula (III), or a salt, solvate or hydrate thereof,

[0711]

[0712] wherein R 11 is H or a protecting group; and R 12 is H or a protecting group.

[0713] Embodiment 41. The compound of Embodiment 40, wherein each protecting group is independently selected from Boc, Fmoc, tert-butyl and trityl groups.

[0714] Embodiment 42. The compound of any one of Embodiments 40-41, wherein R 11 is H or tert-butyl.

[0715] Embodiment 43. The compound of any one of Embodiments 40-42, wherein R 12 is H or tert-butyl.

[0716] Embodiment 44. The compound of any one of Embodiments 40-43, wherein at least one of R 11 and R 12 is a protecting group.

[0717] Embodiment 45. The compound of any one of Embodiments 40-43, wherein R 11 and R 12 are H.

[0718] Embodiment 46. The compound of Embodiment 40, wherein the compound is a compound of the following formula:

[0719]

[0720] Embodiment 47. The compound of any one of Embodiments 40-46, wherein the compound is a solvate.

[0721] Embodiment 48. The compound of any one of Embodiments 40-46, wherein the compound is crystalline.

[0722] Embodiment 49. The compound of Embodiment 48, wherein the compound is in the form of a crystalline solid, and the crystalline solid is characterized by a peak at a diffraction angle 2θ of 8.0° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 7.0°, 10.3°, 14.1°, 15.2°, 16.7°, 18.0°, 19.0°, 19.7°, 20.8°, and 21.9°.

[0723] Embodiment 50. The compound of Embodiment 48, wherein the compound is in the form of a crystalline solid, and the crystalline solid is characterized by a peak at a diffraction angle 2θ of 9.0° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 5.7°, 9.9°, 16.2°, 17.1°, 17.9°, 18.1°, 18.4°, 18.8°, 19.9°, 20.1°, and 22.5°.

[0724] Embodiment 51. The compound of Embodiment 48, wherein the compound is in the form of a crystalline solid, and the crystalline solid is characterized by a peak at a diffraction angle 2θ of 10.5° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 5.6°, 11.9°, 13.3°, 15.4°, 15.6°, 18.1°, 19.9°, and 21.1°.

[0725] Embodiment 52. The compound of Embodiment 48, wherein the compound is in the form of a crystalline solid, and the crystalline solid is characterized by a peak at a diffraction angle 2θ of 10.7° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 4.9°, 14.8°, 20.3°, and 21.5°.

[0726] Embodiment 53. The compound of Embodiment 48, wherein the compound is in the form of a crystalline solid, and the crystalline solid is characterized by a peak at a diffraction angle 2θ of 10.5° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 5.9°, 10.5°, 10.9°, 12.1°, 13.1°, 15.9°, 17.5°, 20.9°, 21.1°, and 21.9°.

[0727] Embodiment 54. The compound of Embodiment 48, wherein the compound is in the form of a crystalline solid, and the crystalline solid is characterized by a peak at a diffraction angle 2θ of 7.8° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 11.3°, 11.5°, 15.4°, 15.6°, and 21.5°.

[0728] Embodiment 55. The compound of Embodiment 48, wherein the compound is in the form of a crystalline solid, and the crystalline solid is characterized by a peak at a diffraction angle 2θ of 10.0° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 8.1°, 12.5°, 13.5°, 14.7°, 17.8°, 18.8°, 20.0° and 22.4°.

[0729] Embodiment 56. The compound of Embodiment 48, wherein the compound is in the form of a crystalline solid, and the crystalline solid is characterized by a peak at a diffraction angle 2θ of 21.1° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 5.6°, 10.5°, 10.8°, 11.9°, 15.4° and 23.8°.

[0730] Embodiment 57. A method for synthesizing the polypeptide of SEQ ID NO:1, the method comprising (i) conjugating the compound of any one of Embodiments 40 - 46 to the C-terminus of the polypeptide of SEQ ID NO:6 through the N-terminus of the compound to form the polypeptide of SEQ ID NO:7; and (ii) conjugating the polypeptide of SEQ ID NO:7 to the N-terminus of the polypeptide of SEQ ID NO:8 through its C-terminus.

[0731] Embodiment 58. A compound of formula (IV), or a salt, solvate or hydrate thereof,

[0732]

[0733] wherein R 13 is H or a protecting group; R 13* is H or a protecting group; R 14 is H or a protecting group; and R 15 is H or a protecting group

[0734] Embodiment 59. The compound of Embodiment 58, wherein each protecting group is independently selected from Boc, Fmoc, tert-butyl and trityl groups.

[0735] Embodiment 60. The compound of any one of Embodiments 58 - 59, wherein R 13 is H, Fmoc or Boc.

[0736] Embodiment 61. The compound of any one of Embodiments 58 - 60, wherein R 13* is H.

[0737] Embodiment 62. The compound of any one of Embodiments 58 - 61, wherein R 14 is H or tert-butyl.

[0738] Compound of any one of embodiments 63. Embodiments 58 - 62, wherein R 15 is H or tert - butyl.

[0739] Compound of any one of embodiments 64. Embodiments 58 - 63, wherein R 13 , R 13 *, R 14 and R 15 in at least one of them is a protecting group.

[0740] Compound of any one of embodiments 65. Embodiments 58 - 63, wherein R 13 , R 13* , R 14 and R 15 are H.

[0741] Compound of embodiment 66. Embodiment 58, wherein the compound has the formula:

[0742]

[0743] Compound of any one of embodiments 67. Embodiments 58 - 66, wherein the compound is a solvate.

[0744] Compound of any one of embodiments 68. Embodiments 58 - 66, wherein the compound is crystalline.

[0745] Compound of embodiment 69. Embodiment 68, wherein the compound is in the form of a crystalline solid, and the crystalline solid is characterized by a peak at a diffraction angle 2θ of 5.1° ± 0.2 degrees in the X - ray powder diffraction pattern and one or more peaks selected from 4.3°, 6.1°, 8.0°, 10.1° and 18.7°.

[0746] Compound of embodiment 70. Embodiment 68, wherein the compound is in the form of a crystalline solid, and the crystalline solid is characterized by a peak at a diffraction angle 2θ of 5.2° ± 0.2 degrees in the X - ray powder diffraction pattern and one or more peaks selected from 6.0°, 6.7°, 10.0°, 10.3°, 16.4°, 17.8°, 18.3°, 19.4° and 22.4°.

[0747] Method for synthesizing the polypeptide of SEQ ID NO:1, the method comprising (i) conjugating the compound of any one of claims 58 - 66 through the N - terminus of the compound to the C - terminus of the polypeptide of SEQ ID NO:9 to form the polypeptide of SEQ ID NO:7; and (ii) conjugating the polypeptide of SEQ ID NO:7 through its C - terminus to the N - terminus of the polypeptide of SEQ ID NO:8.

[0748] Embodiment 72. A compound of Embodiment 58, wherein the compound has the formula:

[0749]

[0750] wherein R 54 is H or a protecting group; R 55 is H or a protecting group; and R 56 is H or a protecting group.

[0751] Embodiment 73. A compound of Embodiment 72, wherein each protecting group is independently selected from Boc, Fmoc, tert-butyl, and trityl groups.

[0752] Embodiment 74. A compound of any one of Embodiments 72-73, wherein R 54 is H or tert-butyl.

[0753] Embodiment 75. A compound of any one of Embodiments 72-74, wherein R 55 is H or tert-butyl.

[0754] Embodiment 76. A compound of any one of Embodiments 72-75, wherein R 56 is H or Boc.

[0755] Embodiment 77. A compound of any one of Embodiments 72-76, wherein at least one of R 54 , R 55 , and R 56 is H.

[0756] Embodiment 78. A compound of any one of Embodiments 72-77, wherein at least one of R 54 , R 55 , and R 56 is a protecting group.

[0757] Embodiment 79. A compound of Embodiment 72, wherein the compound has the formula:

[0758]

[0759] Embodiment 80. A compound of any one of Embodiments 72-79, wherein the compound is a solvate.

[0760] Embodiment 81. A compound of Embodiment 80, wherein the compound is a solvate derived from acetone.

[0761] Embodiment 82. A compound of any one of Embodiments 72-79, wherein the compound is a desolvate.

[0762] Embodiment 83. A compound of any one of Embodiments 72-79, wherein the compound is crystalline.

[0763] Embodiment 84. The compound of Embodiment 83, wherein the compound is in the form of a crystalline solid, and the crystalline solid is characterized by peaks at diffraction angles 2-θ of 5.8° and 18.5° ± 0.2 degrees in an X-ray powder diffraction pattern and one or more peaks selected from 8.6°, 9.4°, 12.9°, 13.8°, 17.2°, and 19.4°.

[0764] Embodiment 85. The compound of Embodiment 83, wherein the compound is in the form of a crystalline solid, and the crystalline solid is characterized by peaks at diffraction angles 2-θ of 7.0-7.1° and 7.5-7.7° ± 0.2 degrees in an X-ray powder diffraction pattern and one or more peaks selected from 5.3-5.4°, 9.7-9.9°, and 14.7-14.9°.

[0765] Embodiment 86. The compound of Embodiment 83, wherein the compound is in the form of a crystalline solid, and the crystalline solid is characterized by a peak at a diffraction angle 2-θ of 8.3° ± 0.2 degrees in an X-ray powder diffraction pattern and one or more peaks selected from 6.3°, 11.4°, 14.3°, and 16.6°.

[0766] Embodiment 87. The compound of Embodiment 83, wherein the compound is in the form of a crystalline solid, and the crystalline solid is characterized by a peak at a diffraction angle 2-θ of 7.2° ± 0.2 degrees in an X-ray powder diffraction pattern and one or more peaks selected from 6.8°, 8.6°, 15.8°, and 18.9°.

[0767] Embodiment 88. The compound of Embodiment 83, wherein the compound is in the form of a crystalline solid, and the crystalline solid is characterized by a peak at a diffraction angle 2-θ of 6.1° ± 0.2 degrees in an X-ray powder diffraction pattern and one or more peaks selected from 6.3°, 7.8°, 10.0°, and 12.4°.

[0768] Embodiment 89. A method for synthesizing the compound of Embodiment 72, the method comprising:

[0769] - reacting a compound of formula (Fmoc-G) with a compound of formula (P prot ) to form a compound of formula (Fmoc-G-P prot )

[0770]

[0771] wherein R57 is a protecting group;

[0772] - Remove the protecting group R 57 to form a compound of (Fmoc-G-P)

[0773]

[0774] - React the compound of formula (Fmoc-G-P) with a compound of formula (S prot2 ) to form a compound of formula (Fmoc-G-P-S prot2 )

[0775]

[0776] wherein R 54 and R 58 are protecting groups;

[0777] - Remove the protecting group R 58 to form a compound of (Fmoc-G-P-S prot1 )

[0778]

[0779] - React the compound of formula (Fmoc-G-P-S prot1 ) with a compound of formula (S prot2 ) to form a compound of formula (Fmoc-G-P-S prot1 -S prot2 )

[0780]

[0781] wherein R 55 and R 59 are protecting groups; and

[0782] - Remove the protecting group R 59 to form a compound of (Fmoc-F-G prot1 -S prot1 -S prot1 )

[0783]

[0784] - React the compound of formula (Fmoc-G-P-S prot1 -S prot1 ) with a compound of formula (G prot ) to form a compound of formula (Fmoc-G-P-S prot1 -S prot1 -G prot )

[0785]

[0786] wherein R 60 is a protecting group;

[0787] - converting a compound of formula (Fmoc-G-P-S prot1 -S prot1 -G prot ) into the compound according to claim 36

[0788] and

[0789] - optionally removing one or more protecting groups R 54 、R 55 and R 56 .

[0790] Embodiment 90. The method of Embodiment 89, wherein each protecting group is independently selected from Boc, Fmoc, tert-butyl and trityl groups.

[0791] Embodiment 91. A method for synthesizing the polypeptide of SEQ ID NO:12, the method comprising: (i) conjugating a compound of any one of Embodiments 72-79 to the N-terminus of the polypeptide of SEQ ID NO:22 through the C-terminus of the compound, and (ii) conjugating the resulting compound to the C-terminus of the polypeptide of SEQ ID NO:23 through its N-terminus.

[0792] Embodiment 92. A method for synthesizing the polypeptide of SEQ ID NO:24, the method comprising conjugating a compound of any one of Embodiments 72-79 to the N-terminus of the polypeptide of SEQ ID NO:22 through the C-terminus of the compound.

[0793] Embodiment 93. A method for synthesizing the polypeptide of SEQ ID NO:16, the method comprising conjugating a compound of any one of Embodiments 72-79 to the C-terminus of the polypeptide of SEQ ID NO:25 through the N-terminus of the compound.

[0794] Embodiment 94. A method for synthesizing the polypeptide of SEQ ID NO:1, the method comprising: (i) conjugating a compound of any one of Embodiments 72-79 to the N-terminus of the polypeptide of SEQ ID NO:8 through the C-terminus of the compound, and (ii) conjugating the resulting compound to the C-terminus of the polypeptide of SEQ ID NO:9 through its N-terminus.

[0795] Embodiment 95. A compound of formula (V), or a salt, solvate or hydrate thereof,

[0796]

[0797] wherein R 16 is H or a protecting group; R 17 is H or a protecting group; R 18 is H or a protecting group; R 19 is H or a protecting group; R 20 is H or a protecting group; and R 21 is H or a protecting group.

[0798] Embodiment 96. A compound according to Embodiment 95, wherein each protecting group is independently selected from Boc, Fmoc, tert-butyl and trityl groups.

[0799] Embodiment 97. A compound according to any one of Embodiments 95-96, wherein R 16 is H, Fmoc or Boc.

[0800] Embodiment 98. A compound according to any one of Embodiments 95-97, wherein R 17 is H or tert-butyl.

[0801] Embodiment 99. A compound according to any one of Embodiments 95-98, wherein R 18 is H or tert-butyl.

[0802] Embodiment 100. A compound according to any one of Embodiments 95-99, wherein R 19 is H or tert-butyl.

[0803] Embodiment 101. A compound according to any one of Embodiments 95-100, wherein R 20 is H or tert-butyl.

[0804] Embodiment 102. A compound according to any one of Embodiments 95-101, wherein R 21 is H or benzyl.

[0805] Embodiment 103. A compound according to any one of Embodiments 95-102, wherein at least one of R 16 , R 17 , R 18 , R 19 , R 20 and R 21 is a protecting group.

[0806] Embodiment 104. A compound according to any one of Embodiments 95-102, wherein R 16 , R 17 , R 18 , R 19 , R 20 and R21 is H.

[0807] Embodiment 105. A compound of Embodiment 95, wherein the compound has the formula:

[0808]

[0809] Embodiment 106. A compound of any one of Embodiments 95 - 105, wherein the compound is a solvate.

[0810] Embodiment 107. A compound of any one of Embodiments 95 - 105, wherein the compound is crystalline.

[0811] Embodiment 108. A compound of Embodiment 107, wherein the compound is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2θ of 5.8 - 6.1° ± 0.2 degrees in the X - ray powder diffraction pattern and one or more peaks selected from 6.7 - 7.1° and 8.8 - 9.0°.

[0812] Embodiment 109. A compound of Embodiment 107, wherein the compound is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2θ of 5.0 - 5.2° ± 0.2 degrees in the X - ray powder diffraction pattern and one or more peaks selected from 5.3 - 5.4°, 5.7 - 6.0°, 6.1 - 6.2°, 7.6 - 7.9° and 8.7 - 9.1°.

[0813] Embodiment 110. A method for synthesizing the polypeptide of SEQ ID NO:1, the method comprising (i) conjugating a compound of any one of Embodiments 95 - 105 to the C - terminus of the polypeptide of SEQ ID NO:3 through the N - terminus of the compound to form the polypeptide of SEQ ID NO:10; and (ii) conjugating the polypeptide of SEQ ID NO:10 to the N - terminus of the polypeptide of SEQ ID NO:11 through its C - terminus.

[0814] Embodiment 111. A compound of formula (VI), or a salt, solvate or hydrate thereof,

[0815]

[0816] wherein R 22 is H or a protecting group; R 23 is H or a protecting group; R 24 is H or a protecting group, and R 25 is H or a protecting group.

[0817] Embodiment 112. The compound of Embodiment 111, wherein each protecting group is independently selected from Boc, Fmoc, tert-butyl, and trityl groups.

[0818] Embodiment 113. The compound of any one of Embodiments 111-112, wherein R 22 is H or Boc.

[0819] Embodiment 114. The compound of any one of Embodiments 111-113, wherein R 23 is H or tert-butyl.

[0820] Embodiment 115. The compound of any one of Embodiments 111-114, wherein R 24 is H or trityl.

[0821] Embodiment 116. The compound of any one of Embodiments 111-115, wherein R 25 is H or tert-butyl.

[0822] Embodiment 117. The compound of any one of Embodiments 111-116, wherein at least one of R 22 , R 23 , R 24 , and R 25 is H.

[0823] Embodiment 118. The compound of any one of Embodiments 111-117, wherein at least one of R 22 , R 23 , R 24 , and R 25 is a protecting group.

[0824] Embodiment 119. The compound of Embodiment 111, wherein the compound is of formula (VI-a):

[0825]

[0826] Embodiment 120. The compound of any one of Embodiments 111-119, wherein the compound is a solvate.

[0827] Embodiment 121. The compound of Embodiment 120, wherein the compound is a solvate derived from amyl acetate, a mixture containing amyl acetate, ethyl acetate, or a mixture containing 2-methyltetrahydrofuran and tert-amyl methyl ether.

[0828] Embodiment 122. The compound of Embodiment 121, wherein the mixture containing amyl acetate is selected from the mixture containing amyl acetate and tert-butyl ethyl ether, the mixture containing amyl acetate and tert-amyl methyl ether, or the mixture containing amyl acetate and heptane.

[0829] Embodiment 123. The compound of any one of Embodiments 111-119, wherein the compound is a desolvate or a partial desolvate.

[0830] Embodiment 124. The compound of any one of Embodiments 111-119, wherein the compound is crystalline.

[0831] Embodiment 125. The compound of Embodiment 124, wherein the compound is in the form of a crystalline solid, and the crystalline solid is characterized by a peak at a diffraction angle 2-θ of 6.3-6.4° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 4.5°, 7.1°, 13.0-13.1°, 15.9-16.0°, and 18.4-18.6°.

[0832] Embodiment 126. The compound of Embodiment 124, wherein the compound is in the form of a crystalline solid, and the crystalline solid is characterized by a peak at a diffraction angle 2-θ of 7.0-7.2° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 5.0-5.4°, 7.6-7.7°, 8.8-8.9°, 9.4-9.5°, and 12.5-12.7°.

[0833] Embodiment 127. A method for synthesizing the compound of Embodiment 111, the method comprising:

[0834] - Reacting a compound of formula (Y prot ) with a compound of formula (Aib prot ) to form a compound of formula (Y prot -Aib prot )

[0835]

[0836] wherein R 22 , R 23 and R 26 are protecting groups;

[0837] - Removing the protecting group R 26 to form a compound of (Y prot -Aib)

[0838]

[0839] - Reacting a compound of formula (Yprot -Aib) compounds react with compounds of formula (Q prot2 ) to form compounds of formula (Y prot -Aib-Q prot2 ) compounds

[0840]

[0841] wherein R 24 and R 27 are protecting groups;

[0842] - Remove the protecting group R 27 to form (Y prot -Aib-Q prot1 ) compounds

[0843]

[0844] - React the compound of formula (Y prot -Aib-Q prot1 ) with a compound of formula (G prot ) to form a compound of formula (VI)

[0845]

[0846] wherein R 25 is a protecting group; and

[0847] - Optionally remove one or more protecting groups R 22 , R 23 , R 24 and R 25 .

[0848] Embodiment 128. The method of Embodiment 127, wherein each protecting group is independently selected from Boc, Fmoc, tert-butyl, and trityl groups.

[0849] Embodiment 129. A method for synthesizing a polypeptide of SEQ ID NO:12, the method comprising conjugating a compound of any one of Embodiments 111-119 to the N-terminus of a polypeptide of SEQ ID NO:13 through the C-terminus of the compound.

[0850] Embodiment 130. A method for synthesizing a polypeptide of SEQ ID NO:14, the method comprising conjugating a compound of any one of Embodiments 111-119 to the N-terminus of a polypeptide of SEQ ID NO:15 through the C-terminus of the compound.

[0851] Embodiment 131. A compound of formula (VII), or a salt, solvate, or hydrate thereof,

[0852]

[0853] wherein R 28 is H or a protecting group; R 29 is H or a protecting group, and R 30 is H or a protecting group.

[0854] Embodiment 132. A compound according to Embodiment 131, wherein each protecting group is independently selected from Boc, Fmoc, tert-butyl, and trityl groups.

[0855] Embodiment 133. A compound according to any one of Embodiments 131-132, wherein R 28 is H or Boc.

[0856] Embodiment 134. A compound according to any one of Embodiments 131-133, wherein R 29 is H or trityl.

[0857] Embodiment 135. A compound according to any one of Embodiments 131-134, wherein R 30 is H or tert-butyl.

[0858] Embodiment 136. A compound according to any one of Embodiments 131-135, wherein at least one of R 28 , R 29 and R 30 is H.

[0859] Embodiment 137. A compound according to any one of Embodiments 131-136, wherein at least one of R 28 , R 29 and R 30 is a protecting group.

[0860] Embodiment 138. A compound according to Embodiment 131, wherein the compound is of formula (VII-a):

[0861]

[0862] Embodiment 139. A compound according to any one of Embodiments 131-137, wherein the compound is a solvate.

[0863] Embodiment 140. A compound according to Embodiment 139, wherein the compound is a solvate generated from any one of the following: a mixture of acetonitrile and methyl tert-butyl ether, a mixture of nitromethane and methyl tert-butyl ether, a mixture of tetrahydrofuran and methyl tert-butyl ether, methyl acetate, and ethyl acetate.

[0864] Embodiment 141. A compound of any one of Embodiments 131-137, wherein the compound is crystalline.

[0865] Embodiment 142. The compound of Embodiment 141, wherein the compound is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2-θ of 4.8° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 5.6°, 6.2°, 14.8°, and 15.6°.

[0866] Embodiment 143. The compound of Embodiment 141, wherein the compound is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2-θ of 5.3° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 7.7°, 10.5°, 11.3°, 11.6°, and 14.4°.

[0867] Embodiment 144. The compound of Embodiment 141, wherein the compound is in the form of a crystalline solid, the crystalline solid being characterized by peaks at diffraction angles 2-θ of 6.2° and 6.9° ± 0.2 degrees in the X-ray powder diffraction pattern.

[0868] Embodiment 145. A method for synthesizing the compound of Embodiment 131, the method comprising:

[0869] - Reacting a compound of formula (H(dnp) prot ) with a compound of formula (Aib prot ) to form a compound of formula (H(dnp) prot -Aib prot )

[0870]

[0871] wherein R 28 and R 31 are protecting groups;

[0872] - Removing the protecting group R 31 to form a compound of (H(dnp) prot -Aib)

[0873]

[0874] - Reacting a compound of formula (H(dnp) prot -Aib) with a compound of formula (Q prot2 ) to form a compound of formula (H(dnp) prot -Aib-Q prot2 )

[0875]

[0876] wherein R 29 and R 32 are protecting groups;

[0877] - Removing the protecting group R 32 to form the compound of (H(dnp) prot -Aib-Q prot1 )

[0878]

[0879] - Reacting the compound of formula (H(dnp) prot -Aib-Q prot1 ) with the compound of formula (G prot ) to form the compound of formula (VII)

[0880]

[0881] wherein R 30 is a protecting group; and

[0882] - Optionally removing one or more protecting groups R 28 , R 29 and R 30 .

[0883] Embodiment 146. The method of embodiment 145, wherein each protecting group is independently selected from Boc, Fmoc, tert-butyl and trityl groups.

[0884] Embodiment 147. A method for synthesizing the polypeptide of SEQ ID NO:16, the method comprising conjugating the C-terminus of the compound of any one of embodiments 131-137 to the N-terminus of the polypeptide of SEQ ID NO:17.

[0885] Embodiment 148. A compound of formula (VIII), or a salt, solvate or hydrate thereof,

[0886]

[0887] wherein R 33 is H or a protecting group; R 34 is H or a protecting group; and R 35 is H or a protecting group.

[0888] Embodiment 149. The compound of embodiment 148, wherein each protecting group is independently selected from Boc, Fmoc, tert-butyl and trityl groups.

[0889] Embodiment 150. A compound according to any one of Embodiments 148 - 149, wherein R 33 is H or Boc.

[0890] Embodiment 151. A compound according to any one of Embodiments 148 - 150, wherein R 34 is H or trityl.

[0891] Embodiment 152. A compound according to any one of Embodiments 148 - 151, wherein R 35 is H or tert - butyl.

[0892] Embodiment 153. A compound according to any one of Embodiments 148 - 152, wherein at least one of R 33 R 34 and R 35 is H.

[0893] Embodiment 154. A compound according to any one of Embodiments 148 - 153, wherein at least one of R 33 R 34 and R 35 is a protecting group.

[0894] Embodiment 155. A compound according to Embodiment 148, wherein the compound is of formula (VIII - a):

[0895]

[0896] Embodiment 156. A compound according to any one of Embodiments 148 - 155, wherein the compound is a solvate.

[0897] Embodiment 157. A compound according to Embodiment 156, wherein the compound is a solvate derived from any one of the following: a mixture of tetrahydrofuran and methyl tert - butyl ether, a mixture of tetrahydrofuran and heptane, a mixture of 1,4 - dioxane and water, a mixture of ethyl acetate and methyl tert - butyl ether, and a mixture of acetonitrile and methyl tert - butyl ether.

[0898] Embodiment 158. A compound according to any one of Embodiments 148 - 155, wherein the compound is crystalline.

[0899] Embodiment 159. A compound according to Embodiment 158, wherein the compound is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2 - θ of 4.7° ± 0.2 degrees and one or more peaks selected from 5.5°, 8.2°, 10.1°, 11.8°, 13.3°, 13.6°, and 18.9° in the X - ray powder diffraction pattern; or

[0900] Embodiment 160. The compound of Embodiment 158, wherein the compound is in the form of a crystalline solid, and the crystalline solid is characterized by a peak at a diffraction angle 2-θ of 5.8° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 5.3°, 8.9°, 9.2°, 15.2°, 18.6°, and 19.5°.

[0901] Embodiment 161. A method for synthesizing the compound of Embodiment 148, the method comprising:

[0902] - reacting a compound of formula (H(trt) prot ) with a compound of formula (Aib prot ) to form a compound of formula (H(trt) prot -Aib prot )

[0903]

[0904] wherein R 33 and R 36 are protecting groups;

[0905] - removing the protecting group R 36 to form a compound of (H(trt) prot -Aib)

[0906]

[0907] - reacting a compound of formula (H(trt) prot -Aib) with a compound of formula (Q prot2 ) to form a compound of formula (H(trt) prot -Aib-Q prot2 )

[0908]

[0909] wherein R 33 and R 37 are protecting groups;

[0910] - removing the protecting group R 37 to form a compound of (H(trt) prot -Aib-Q prot1 )

[0911]

[0912] - reacting a compound of formula (H(trt) prot -Aib-Q prot1 ) with a compound of formula (G prot) The compound of () reacts to form a compound of formula (VIII).

[0913]

[0914] Wherein R 35 is a protecting group; and

[0915] - Optionally removing one or more protecting groups R 33 、R 34 and R 35 .

[0916] Embodiment 162. The method of Embodiment 161, wherein each protecting group is independently selected from Boc, Fmoc, tert - butyl and trityl groups.

[0917] Embodiment 163. A method for synthesizing the polypeptide of SEQ ID NO:16, the method comprising conjugating the C - terminus of the compound of any one of Embodiments 148 - 155 to the N - terminus of the polypeptide of SEQ ID NO:17.

[0918] Embodiment 164. A compound of formula (IX), or a salt, solvate or hydrate thereof,

[0919]

[0920] Wherein R 38 is H or a protecting group; R 39 is H or a protecting group; R 40 is H or a protecting group; R 41 is H or a protecting group; R 42 is H or a protecting group; and R 43 is H or a protecting group.

[0921] Embodiment 165. The compound of Embodiment 164, wherein each protecting group is independently selected from Boc, Fmoc, tert - butyl and trityl groups.

[0922] Embodiment 166. The compound of any one of Embodiments 164 - 165, wherein R 38 is H or Fmoc.

[0923] Embodiment 167. The compound of any one of Embodiments 164 - 166, wherein R 39 is H or tert - butyl.

[0924] Embodiment 168. The compound of any one of Embodiments 164 - 167, wherein R 40 is H or tert - butyl.

[0925] Embodiment 169. A compound of any one of Embodiments 164-168, wherein R 41 is H or tert-butyl.

[0926] Embodiment 170. A compound of any one of Embodiments 164-169, wherein R 42 is H or Boc.

[0927] Embodiment 171. A compound of any one of Embodiments 164-170, wherein R 43 is H or tert-butyl.

[0928] Embodiment 172. A compound of any one of Embodiments 164-171, wherein at least one of R 38 , R 39 , R 40 , R 41 , R 42 and R 43 is H.

[0929] Embodiment 173. A compound of any one of Embodiments 164-172, wherein at least one of R 38 , R 39 , R 40 , R 41 , R 42 and R 43 is a protecting group.

[0930] Embodiment 174. A compound of Embodiment 164, wherein the compound is of formula (IX-a):

[0931]

[0932] Embodiment 175. A compound of any one of Embodiments 164-174, wherein the compound is a solvate.

[0933] Embodiment 176. A compound of Embodiment 175, wherein the compound is a solvate produced from any one of the following: a mixture of methyl acetate and dibutyl ether, a mixture of acetone and dibutyl ether, a mixture of acetonitrile and dibutyl ether, a mixture of ethyl acetate and dibutyl ether, a mixture of methyl acetate and heptane, and a mixture of methyl ethyl ketone and dibutyl ether.

[0934] Embodiment 177. A compound of any one of Embodiments 164-174, wherein the compound is a desolvate or is anhydrous.

[0935] Embodiment 178. A compound of any one of Embodiments 164-174, wherein the compound is crystalline.

[0936] Embodiment 179. The compound of Embodiment 178, wherein the compound is in the form of a crystalline solid, and the crystalline solid is characterized by a peak at a diffraction angle 2-θ of 5.3° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 6.0°, 6.9°, 7.2°, 8.0°, 12.2°, and 15.6°;

[0937] Embodiment 180. The compound of Embodiment 178, wherein the compound is in the form of a crystalline solid, and the crystalline solid is characterized by a peak at a diffraction angle 2-θ of 5.8° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 4.4°, 6.6°, 10.1°, 11.4°, 13.4°, and 15.5°.

[0938] Embodiment 181. The compound of Embodiment 178, wherein the compound is in the form of a crystalline solid, and the crystalline solid is characterized by peaks at diffraction angles 2-θ of 4.5° and 5.5° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 6.0° and 7.3°.

[0939] Embodiment 182. A method for synthesizing the compound of Embodiment 164, the method comprising:

[0940] - Reacting a compound of formula (D prot ) with a compound of formula (Y prot2 ) to form a compound of formula (D prot -Y prot2 )

[0941]

[0942] wherein R 38 , R 39 , R 40 and R 44 are protecting groups;

[0943] - Removing the protecting group R 44 to form a compound of (D prot -Y prot1 )

[0944]

[0945] - Reacting a compound of formula (D prot -Y prot1 ) with a compound of formula (S prot2 ) to form a compound of formula (D prot -Y prot1 -S prot2 )

[0946]

[0947] wherein R 41 and R 45 are protecting groups;

[0948] - Removing the protecting group R 45 to form the compound of (D prot -Y prot1 -S prot1 )

[0949]

[0950] - Reacting the compound of formula (D prot -Y prot1 -S prot1 ) with the compound of formula (K prot2 ) to form the compound of formula (IX)

[0951]

[0952] wherein R 42 and R 43 are protecting groups; and

[0953] - Optionally removing one or more of the protecting groups R 38 , R 39 , R 40 , R 41 , R 42 and R 43 . Embodiment 183. The method of embodiment 182, wherein the protecting group is selected from Boc, Fmoc, tert-butyl and trityl groups.

[0954] Embodiment 184. A method for synthesizing the polypeptide of SEQ ID NO:16, the method comprising: (i) conjugating the C-terminus of the compound of any one of embodiments 164-174 to the N-terminus of the polypeptide of SEQ ID NO:18, and (ii) conjugating the N-terminus of the compound to the C-terminus of the polypeptide of SEQ ID NO:19.

[0955] Embodiment 185. A compound of formula (X), or a salt, solvate or hydrate thereof,

[0956]

[0957] wherein R 46 is H or a protecting group; R 47 is H or a protecting group; R 48 is H or a protecting group; R 49 is H or a protecting group; R50 is H or a protecting group; and R 51 is H or a protecting group.

[0958] Embodiment 186. The compound of Embodiment 185, wherein each protecting group is independently selected from Boc, Fmoc, tert-butyl and trityl groups.

[0959] Embodiment 187. The compound of any one of Embodiments 185-186, wherein R 46 is H or tert-butyl.

[0960] Embodiment 188. The compound of any one of Embodiments 185-187, wherein R 47 is H or tert-butyl.

[0961] Embodiment 189. The compound of any one of Embodiments 185-188, wherein R 48 is H or Boc.

[0962] Embodiment 190. The compound of any one of Embodiments 185-189, wherein R 49 is H or Fmoc.

[0963] Embodiment 191. The compound of any one of Embodiments 185-190, wherein R 50 is H or tert-butyl.

[0964] Embodiment 192. The compound of any one of Embodiments 185-191, wherein R 51 is H or tert-butyl.

[0965] Embodiment 193. The compound of any one of Embodiments 185-192, wherein at least one of R 46 R 47 R 48 R 49 R 50 R 51 and R

[0966] Embodiment 194. The compound of any one of Embodiments 185-193, wherein at least one of R 46 R 47 R 48 R 49 R 50 R 51 and R

[0967] Embodiment 195. The compound of Embodiment 185, wherein the compound is of formula (X-a):

[0968]

[0969] Embodiment 196. A compound according to any one of embodiments 185 - 195, wherein the compound is a solvate.

[0970] Embodiment 197. The compound of embodiment 196, wherein the compound is a solvate derived from ethanol or isopropanol.

[0971] Embodiment 198. A compound according to any one of embodiments 185 - 195, wherein the compound is a desolvate.

[0972] Embodiment 199. A compound according to any one of embodiments 185 - 195, wherein the compound is crystalline.

[0973] Embodiment 200. The compound of embodiment 199, wherein the compound is in the form of a crystalline solid, the crystalline solid being characterized by peaks at diffraction angles 2 - θ of 18.1° and 18.7° ± 0.2 degrees in an X - ray powder diffraction pattern and one or more peaks selected from 5.7°, 8.7°, 13.7°, 14.3°, 15.9°, and 16.2°;

[0974] Embodiment 201. The compound of embodiment 199, wherein the compound is in the form of a crystalline solid, the crystalline solid being characterized by peaks at diffraction angles 2 - θ of 5.9° and 10.5° ± 0.2 degrees in an X - ray powder diffraction pattern and one or more peaks selected from 7.1°, 8.9°, 14.6°, and 16.6°.

[0975] Embodiment 202. The compound of embodiment 199, wherein the compound is in the form of a crystalline solid, the crystalline solid being characterized by peaks at diffraction angles 2 - θ of 7.8° and 20.3° ± 0.2 degrees in an X - ray powder diffraction pattern and one or more peaks selected from 5.8°, 15.5°, and 19.5°.

[0976] Embodiment 203. The compound of embodiment 199, wherein the compound is in the form of a crystalline solid, the crystalline solid being characterized by peaks at diffraction angles 2 - θ of 5.9° and 7.4° ± 0.2 degrees in an X - ray powder diffraction pattern and one or more peaks selected from 6.5°, 6.9°, and 14.8°.

[0977] Embodiment 204. A method for synthesizing the compound of embodiment 185, the method comprising:

[0978] - reacting a compound of formula (Y prot ) with a compound of formula (S prot2 ) to form a compound of formula (Y prot-S prot2 compound of

[0979]

[0980] wherein R 46 and R 47 and R 48 and R 52 are protecting groups;

[0981] - Remove the protecting group R 52 to form a compound of (Y prot -S prot1 )

[0982]

[0983] - React the compound of formula (Y prot -S prot1 ) with a compound of formula (K prot2 ) to form a compound of formula (Y prot -S prot1 -K prot2 )

[0984]

[0985] wherein R 49 and R 53 are protecting groups;

[0986] - Remove the protecting group R 53 to form a compound of (Y prot -S prot1 -K prot1 )

[0987]

[0988] - React the compound of formula (Y prot -S prot1 -K prot1 ) with a compound of formula (Y prot2 ) to form a compound of formula (X)

[0989]

[0990] wherein R 50 and R 51 are protecting groups; and

[0991] - Optionally remove one or more protecting groups R 46 and R 47 and R 48 and R 49 and R 50 and R51 。

[0992] Embodiment 205. The method of Embodiment 204, wherein the protecting group is selected from Boc, Fmoc, tert-butyl and trityl groups.

[0993] Embodiment 206. A method for synthesizing the polypeptide of SEQ ID NO:16, the method comprising: (i) conjugating a compound of any one of Embodiments 185-195 to the N-terminus of the polypeptide of SEQ ID NO:20 through the C-terminus of the compound, and (ii) conjugating the resulting compound to the C-terminus of the polypeptide of SEQ ID NO:21 through its N-terminus.

[0994] Embodiment 207. A compound of formula (XI), or a salt, solvate or hydrate thereof,

[0995]

[0996] wherein R 64 is H or a protecting group; R 65 is H or a protecting group; and R 66 is H or a protecting group.

[0997] Embodiment 208. The compound of Embodiment 207, wherein each protecting group is independently selected from Boc, Fmoc, tert-butyl and trityl groups.

[0998] Embodiment 209. The compound of any one of Embodiments 207-208, wherein at least one of R 64 , R 65 and R 66 is H.

[0999] Embodiment 210. The compound of any one of Embodiments 207-209, wherein at least one of R 64 , R 65 and R 66 is a protecting group.

[1000] Embodiment 211. The compound of Embodiment 207, wherein the compound has the formula:

[1001]

[1002] Embodiment 212. The compound of any one of Embodiments 207-211, wherein the compound is a solvate.

[1003] Embodiment 213. The compound of any one of Embodiments 207-211, wherein the compound is crystalline.

[1004] Embodiment 214. The compound of Embodiment 213, wherein the compound is in the form of a crystalline solid, and the crystalline solid is characterized by peaks at diffraction angles 2-θ of 6.1° and 8.5° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 5.8°, 16.9°, 18.5°, 18.8°, 19.3° and 20.9.

[1005] Embodiment 215. A compound of formula (XII), or a salt, solvate or hydrate thereof,

[1006]

[1007] wherein R 61 is H or a protecting group; R 62 is H or a protecting group; and R 63 is H or a protecting group.

[1008] Embodiment 216. The compound of Embodiment 215, wherein each protecting group is independently selected from Boc, Fmoc, tert-butyl and trityl groups.

[1009] Embodiment 217. The compound of any one of Embodiments 215-216, wherein R 61 is H or tert-butyl.

[1010] Embodiment 218. The compound of any one of Embodiments 215-217, wherein R 62 is H or tert-butyl.

[1011] Embodiment 219. The compound of any one of Embodiments 215-218, wherein R 63 is H or tert-butyl.

[1012] Embodiment 220. The compound of any one of Embodiments 215-219, wherein at least one of R 61 , R 62 and R 63 is H.

[1013] Embodiment 221. The compound of any one of Embodiments 215-220, wherein at least one of R 61 , R 62 and R 63 is a protecting group.

[1014] Embodiment 222. The compound of Embodiment 215, wherein the compound is of formula (XII-a):

[1015]

[1016] Embodiment 223. A compound of any one of Embodiments 215-222, wherein the compound is a solvate.

[1017] Embodiment 224. A compound of any one of Embodiments 215-222, wherein the compound is a desolvate or is anhydrous.

[1018] Embodiment 225. A compound of any one of Embodiments 215-222, wherein the compound is crystalline.

[1019] Embodiment 226. The compound of Embodiment 225, wherein the compound is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2-θ of 11.4° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 6.0°, 8.9°, 12.7°, 13.6°, 14.6°, 17.0°, and 18.8°.

[1020] Embodiment 227. The compound of Embodiment 225, wherein the compound is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2-θ of 10.6° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 7.1°, 12.1°, 13.6°, 14.2°, 15.2°, 16.0°, and 16.8°.

[1021] Embodiment 228. The compound of Embodiment 225, wherein the compound is in the form of a crystalline solid, the crystalline solid being characterized by peaks at diffraction angles 2-θ of 10.1° and 15.5° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 6.1°, 8.7°, 11.4°, 16.6°, and 19.2°.

[1022] Embodiment 229. A compound of formula (XIII), or a salt, solvate, or hydrate thereof,

[1023]

[1024] wherein R 67 is H or a protecting group; R 68 is H or a protecting group; and R 69 is H or a protecting group.

[1025] Embodiment 230. The compound of Embodiment 229, wherein each protecting group is independently selected from Boc, Fmoc, tert-butyl, and trityl groups.

[1026] Embodiment 231. The compound of any one of Embodiments 229-230, wherein R 67 is H or tert-butyl.

[1027] Embodiment 232. A compound of any one of Embodiments 229-231, wherein R 68 is H or tert-butyl.

[1028] Embodiment 233. A compound of any one of Embodiments 229-232, wherein R 69 is H or tert-butyl.

[1029] Embodiment 234. A compound of any one of Embodiments 229-233, wherein at least one of R 67 , R 68 and R 69 is H.

[1030] Embodiment 235. A compound of any one of Embodiments 229-234, wherein at least one of R 67 , R 68 and R 69 is a protecting group.

[1031] Embodiment 236. A compound of Embodiment 229, wherein the compound has the formula:

[1032]

[1033] Embodiment 237. A compound of any one of Embodiments 229-236, wherein the compound is a solvate.

[1034] Embodiment 238. A compound of any one of Embodiments 229-236, wherein the compound is a desolvate or is anhydrous.

[1035] Embodiment 239. A compound of any one of Embodiments 229-236, wherein the compound is crystalline.

[1036] Embodiment 240. A compound of Embodiment 239, wherein the compound is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2-θ of 5.0° ± 0.2 degrees and one or more peaks selected from 8.3, 9.7 and 11.2°.

[1037] Embodiment 241. A compound of Embodiment 239, wherein the compound is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2-θ of 7.2° ± 0.2 degrees and one or more peaks selected from 5.3, 8.1, 14.4 and 16.2°.

[1038] Embodiment 242. A compound of formula (XIV), or a salt, solvate or hydrate thereof,

[1039]

[1040] wherein R 70 is H or a protecting group; R 71 is H or a protecting group; R 72 is H or a protecting group; R 73 is H or a protecting group; and R 74 is H or a protecting group.

[1041] Embodiment 243. The compound of Embodiment 242, wherein each protecting group is independently selected from Boc, Fmoc, tert-butyl and trityl groups.

[1042] Embodiment 244. The compound of any one of Embodiments 242-243, wherein R 70 is H, Fmoc or tert-butyl.

[1043] Embodiment 245. The compound of any one of Embodiments 242-244, wherein R 71 is H or tert-butyl.

[1044] Embodiment 246. The compound of any one of Embodiments 242-245, wherein R 72 is H or tert-butyl.

[1045] Embodiment 247. The compound of any one of Embodiments 242-246, wherein R 73 is H or tert-butyl.

[1046] Embodiment 248. The compound of any one of Embodiments 242-247, wherein R 74 is H, Fmoc or tert-butyl.

[1047] Embodiment 249. The compound of any one of Embodiments 242-248, wherein at least one of R 70 , R 71 , R 72 , R 73 and R 74 is H.

[1048] Embodiment 250. The compound of any one of Embodiments 242-249, wherein at least one of R 70 , R 71 , R 72 , R 73 and R 74 is a protecting group.

[1049] Embodiment 251. A compound according to Embodiment 242, wherein the compound has the formula:

[1050]

[1051] Embodiment 252. A compound according to any one of Embodiments 242 - 251, wherein the compound is a solvate.

[1052] Embodiment 253. A compound according to any one of Embodiments 242 - 251, wherein the compound is a desolvate or is anhydrous

[1053] Embodiment 254. A compound according to any one of Embodiments 242 - 251, wherein the compound is crystalline.

[1054] Embodiment 255. A compound according to Embodiment 254, wherein the compound is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2-θ of 7.5° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 6.1, 8.7, 10.6, 15.0, 16.1, and 18.6°. Example

[1055] Example 1: Boc-l-Tyr(tBu)-Aib-Glu(OtBu)-Gly-OH

[1056]

[1057] Compound 1 ((S)-3-(4-(tert-butoxy)phenyl)-2-((tert-butoxycarbonyl)amino)propanoic acid) was added to 10 volumes (vol) of EtOAc and the temperature was adjusted to -10 to 0 °C. BOP (1.3 equivalents) was added portionwise at -10 to 0 °C. 1.3 equivalents of Compound 2 (benzyl 2-amino-2-methylpropanoate) was added at -10 to 0 °C. DIPEA was added dropwise at -10 to 0 °C and the mixture was stirred at -10 to 0 °C for 16 - 20 hours. The mixture was warmed to 0 - 20 °C and washed 5 times with 10 volumes at 0 - 20 °C. The aqueous layers were combined. The organic layer was washed 2 times with 0.5 mol / L Na2CO3 (5 volumes) at 0 - 20 °C. The organic layer was washed with water (10 volumes) at 0 - 20 °C and the aqueous layers were combined. The organic layer was concentrated to dryness below 40 °C. EtOAc (2 volumes) was added at 15 - 25 °C, the mixture was stirred for 1 hour, and then filtered to obtain a wet filter cake. The filtrate was concentrated to dryness below 40 °C. 5 volumes of EtOH was added to form a clear solution and the temperature was adjusted to 5 - 15 °C. 1 - 2 volumes of water was added dropwise to the mixture, seeds (0.5% w / w) were added to the mixture, and the mixture was stirred for 1 - 2 hours. 3 - 4 volumes of water was added dropwise to the mixture, the mixture was stirred for 16 - 24 hours, and then filtered. The wet filter cake was washed with EtOH / water (1 / 1 volume / volume). The wet filter cake was dried in vacuo at 35 - 45 °C for 20 - 24 hours to afford Preparation 1.

[1058] 1 equivalent of Preparation 1 was mixed with Pd / C (0.1×). MeOH (10.5×, 13.3 volumes) was added to the mixture and the argon was exchanged 3 times, then the hydrogen was exchanged 3 times. The pressure was adjusted to 45 psi with hydrogen, the mixture was heated to 40 °C, and stirred for 18 - 24 hours. The mixture was cooled to 20 - 30 °C, the argon was exchanged 3 times, and the mixture was filtered. The wet filter cake was washed with MeOH (1 volume) and the filtrate was transferred into a container and concentrated to below 2 volumes (-2 vol) below 45 °C. EA (300 ml, 3 volumes) was added and the mixture was concentrated to below 2 volumes (-2 vol) below 45 °C, EA (300 ml, 3 volumes) was added and the mixture was concentrated to below 2 volumes (-2 vol) below 45 °C. Heptane (8 volumes) was added dropwise, the mixture was stirred at 20 - 35 °C for 20 - 24 hours, and then the mixture was filtered. The wet filter cake was washed with heptane (1 volume) and then dried in vacuo at 40 to 50 °C for 20 - 24 hours to afford Preparation 2.

[1059] Add THF to Container 1 and cool to 0 °C. Mix IBCF (1.3 eq, 0.42×) with Preparation 2 (1.0×). Add 3 volumes of THF to another Container 2 and add NMM (1.35 eq, 0.325×), then add this mixture to the mixture containing Preparation 2 and stir for 4 - 6 hours. Add 3 volumes of THF to Container 2, then add 3 volumes of water, and stir the mixture at 15 - 20 °C for 30 min. Add the content of Container 2 to Container 1 at 0 - 5 °C. Heat the content of Container 1 to 20 °C over 3 - 4 hours and stir for 16 - 20 hours. Add 15 volumes of EA to Container 1 and separate the organic layer. Add 5% aqueous KHSO4 solution (16 volumes) to the organic layer at 15 - 25 °C, stir the mixture for 1 - 2 hours and separate the organic layer, and wash it twice with 5% NaCl (10 volumes). Concentrate the mixture in Container 1 to less than 1 volume (-1 vol) below 45 °C, add THF (5 volumes) and concentrate the mixture to less than 1 volume (-1 vol). Add IPA / H2O 1:2 (10.5 volumes) and stir the mixture at 15 - 25 °C for 48 hours. Then filter the mixture, wash the wet cake twice with IPA / H2O 1:2 (1 volume), and dry the wet cake in vacuo at 40 - 45 °C for 20 - 24 hours to produce Preparation 3.

[1060] Add Preparation 3 (1.0×) to benzyl glycinate (1.3 eq, 0.44×) and then add 10 volumes of ACN. Add 2,6 - dimethylpyridine (3.0 eq, 0.53×) and adjust the temperature to -10 °C. Add COMU (1.3 eq, 0.86×) at -10 °C and stir the mixture for 2 - 4 hours. Concentrate the mixture to less than 1 volume (-1 vol) below 45 °C, add EA (10 volumes), and stir the mixture at 15 - 20 °C for 0.5 - 1 hour. Then filter the mixture and wash the wet cake with EA (1 volume). Add the filtrate and concentrate it to less than 1 volume (-1 vol) below 45 °C. Add MTBE (10 volumes) and stir the mixture at 15 - 20 °C for 0.5 - 1 hour. Then filter the mixture and wash the wet cake with MTBE (1 volume). Wash the filtrate twice with 0.5 ml / L aqueous Na2CO3 solution (10 volumes) at 15 - 25 °C, twice with 5% aqueous KHSO4 solution (10 volumes) at 15 - 25 °C, and with water (10 volumes) at 15 - 25 °C. Separate the organic layer and concentrate it to 1 - 2 volumes below 45 °C. Add MTBE (10 volumes) and heat the mixture to 40 °C and cool to 10 °C over 2 hours. Filter the mixture, and dry the cake at 45 °C for 16 - 24 hours to produce Preparation 4.

[1061] Preparation 4 (1×, 1 equivalent) was added to IPA (7.92×, 10 volumes), Pd / C (0.1×) was added, the argon was exchanged 3 times, then the hydrogen was exchanged 3 times, the pressure was adjusted to 45 psi with hydrogen, and the mixture was heated to 40 °C and stirred for 18 - 24 hours. The mixture was cooled to 20 - 30 °C, the argon was exchanged 3 times, the mixture was filtered, the wet cake was washed with IPA (1 volume), and the filtrate was concentrated to less than 1 volume (-1 vol) below 45 °C. MTBE (3 volumes) was added, and the mixture was concentrated to less than 1 volume (-1 vol) below 45 °C. MTBE (10 volumes) and IPA (0.5 volume) were added to the mixture, and the mixture was heated to 40 °C, cooled to 20 °C over 2 hours, and stirred at 20 °C for 2 - 6 hours. The solid was filtered, the wet cake was washed with 1 volume of MTBE, and the wet cake was dried under vacuum at 40 - 50 °C for 16 - 24 hours to produce Y-Aib-E-G.

[1062] Preparation of Forms A, B, and C of Y-Aib-E-G

[1063] Three solid forms of the Y-Aib-E-G tetramer were prepared: Form A, Form B, and Form C. Y-Aib-E-G Form A is a solvated form produced from MTBE or a mixture containing MTBE (such as MTBE / IPA, MTBE / heptane, etc.). Y-Aib-E-G Form B is a desolvated form produced from Form A by drying at high temperature / vacuum, heating to 110 °C, or exposure to 75% RH, etc. Y-Aib-E-G Form C is a hydrate that contains different amounts of water in the unit cell, including the case of zero water content.

[1064] Crystallization of Y-Aib-E-G helps to remove impurities from the crude material. The crystalline Y-Aib-E-G showed higher purity based on UPLC-MS analysis compared to amorphous crude Y-Aib-E-G. Crystallization of crude Y-Aib-E-G doped with 1% dimer (impurity) produced crystalline Y-Aib-E-G with almost complete removal of the dimer. Crystallization also improves physical properties, such as hygroscopicity. By dynamic vapor sorption (DVS) analysis, amorphous Y-Aib-E-G showed a 4.1 wt% absorption increase from 0% to 95% RH, while Y-Aib-E-G Form B showed only a 1.4 wt% increase under the same conditions.

[1065] XRPD patterns of the crystalline TZP tetramer were obtained on a Bruker D8 Endeavor X-ray powder diffractometer equipped with CuKα A source and a Linxeye detector were used, operating at 40 kV and 40 mA. The sample was scanned between 4 and 42 2θ°, with a step size of 0.009 2θ°, and a scan rate of 0.5 seconds per step, using a 0.3° primary slit opening and a 3.9° PSD opening. In some cases, the sample was scanned between 4 and 30 2θ° at a scan rate of 0.25 seconds per step. The powder was packed in a quartz sample holder, and a glass slide was used to obtain a smooth surface. Diffraction patterns of the crystal form were collected at ambient temperature and relative humidity. The crystal peak positions were determined in MDI-Jade v7.9.9. In the field of crystallography, it is well known that for any given crystal form, the relative intensities of the diffraction peaks may vary due to preferred orientation caused by factors such as crystal morphology and habit. In the presence of preferred orientation effects, the peak intensities are altered, but the characteristic peak positions of the polymorphs remain unchanged. See, for example, The United States Pharmacopeia #23, National Formulary #18, pages 1843 - 1844, 1995. Additionally, in the field of crystallography, it is also well known that for any given crystal form, the angular peak positions may vary slightly.

[1066] For example, the peak positions may shift due to changes in temperature during analysis of the sample, sample displacement, or the presence or absence of an internal standard. In this case, a peak position variability of ±0.2 2θ° was assumed to account for these potential variations without preventing the clear identification of the indicated crystal form. The crystal form can be confirmed based on any unique combination of distinguishable peaks.

[1067] Y-Aib-E-G Form A

[1068] 0.2 mL of MTBE was added to 110.9 mg of amorphous solid of Y-Aib-E-G and the sample was stirred under ambient conditions. After 4 days, an additional 0.4 mL of MTBE was added to the mixture and the sample was stirred for another day. A white slurry was obtained, which was transferred to a 0.45 μm nylon centrifuge tube filter and centrifuged at ambient temperature for 5 minutes, and the resulting white solid was consistent with Y-Aib-E-G Form A.

[1069] The prepared sample of Y-Aib-E-G Form A was characterized by XRPD patterns using CuKα radiation as having diffraction peaks (2-θ values) as shown in Table 1 below, and particularly having a peak at 5.2° 2-θ and one or more peaks selected from 9.9, 10.4, 15.5, and 17.1° 2-θ; the tolerance of the diffraction angle is 0.2 degrees. A representative XRPD pattern of Y-Aib-E-G Form A is shown in Figure 1A in.

[1070] Table 1. X-ray powder diffraction peaks of Y-Aib-E-G Form A

[1071]

[1072] Y-Aib-E-G Form B

[1073] 6 mL of MTBE was added to 1.01 g of the amorphous solid of Y-Aib-E-G and the sample was stirred for 5 days under ambient conditions, which produced a white slurry. The slurry was transferred to a 0.45 μm nylon centrifuge tube filter and centrifuged for 5 minutes at ambient temperature, and the resulting white solid (0.78 g) was substantially identical to Y-Aib-E-G Form A. 81.6 mg of such white solid was dried under vacuum at about 50 °C for 1 day. The resulting white solid was identical to Y-Aib-E-G Form B.

[1074] The sample of the prepared Y-Aib-E-G Form B was characterized by XRPD patterns using CuKα radiation as having the diffraction peaks (2-θ values) described in Table 2 below, and particularly having a peak at 6.1° 2-θ and one or more peaks selected from 10.3, 16.8 and 18.1° 2-θ; the tolerance of the diffraction angle was 0.2 degrees. A representative XRPD pattern of Y-Aib-E-G Form B is shown in Figure 1B in.

[1075] Table 2. X-ray powder diffraction peaks of Y-Aib-E-G Form B

[1076]

[1077] Y-Aib-E-G Form C

[1078] 285.8 mg of amorphous Y-Aib-E-G was stirred overnight in 1 mL of water under ambient conditions, producing a thick slurry; an additional amount of water (2 × 0.5 mL) and IPA (2 × 0.1 mL) were added to the slurry and the sample was stirred for an additional 6 days under ambient conditions. An off-white slurry was obtained, which was transferred to a 0.45 μm nylon centrifuge tube filter and centrifuged for 5 minutes at ambient temperature. The separated solid was white and moist, and it was dried under vacuum at 70 - 78 °C for 2 hours. The resulting white solid was identical to Y-Aib-E-G Form C.

[1079] The sample of the prepared Y-Aib-E-G Form C was characterized by XRPD patterns using CuKα radiation as having the diffraction peaks (2-θ values) described in Table 3 below, and particularly having a peak at 6.2° 2-θ and one or more peaks selected from 9.5, 13.6 and 21.8° 2-θ; the tolerance of the diffraction angle was 0.2 degrees. A representative XRPD pattern of Y-Aib-E-G Form C is shown in Figure 1C in.

[1080] Table 3. X-ray powder diffraction peaks of the Y-Aib-E-G tetramer form C

[1081]

[1082] The Y-Aib-E-G tetramer is coupled with the 10-mer for TZP synthesis

[1083]

[1084] Crystalline Y-Aib-E-G can be used as a starting material to generate the TZP fragment (amino acids 1-14) through a coupling reaction with the fragment 10-mer (amino acids 5-14). The TZP fragment (amino acids 1-14) can then be coupled with other fragments to produce the protected TZP as an active pharmaceutical ingredient (API).

[1085] The protected TZP fragment 10-mer (amino acids 5-14) on resin (1.2518 g, 0.500 mmol) in a 45 ml automated synthesizer reactor was swollen with 3×15 ml of DMF for 15 minutes each, deprotected with 3×15 ml of 20% piperidine / DMF for 30 minutes each, and washed with 5×15 ml of DMF for 1 minute each. A solution of the TZP tetramer (1.055 g, 1.500 mmol, 94.53 mass %) and ethyl cyanoacetate-2-oxime (214.3 mg, 1.500 mmol, 99 mass %) in 9 ml of DMF was prepared. N,N'-Diisopropylcarbodiimide (258 μL, 1.650 mmol, 100 mass %) was added, and the resulting yellow solution was allowed to stand for 30 minutes with occasional shaking, then the solution was added to the reactor containing the resin. The reactants were mixed at ambient temperature for 18 hours and then drained. The resin was washed with 5×15 ml of DMF for 1 minute each, 5×15 ml of DCM for 1 minute each, and then drained and dried for 4 hours to a constant weight of 1.4077 g.

[1086] For analysis, approximately 300 mg of resin was treated with 5 mL of a solution composed of trifluoroacetic acid (4.64 mL, 61.4 mmol, 100 mass %), triisopropylsilane (125 μL, 0.609 mmol, 100 mass %), water (125 μL, 6.93874 mmol, 100 mass %), and DTT (125 mg, 0.810357 mmol, 100 mass %). The mixture was stirred on a rotary mixer for 2 hours, filtered, and washed with trifluoroacetic acid (2 mL, 26.45 mmol, 100 mass %). The combined filtrate and washings were added to 35 mL of cold MTBE in a centrifuge tube. After 30 minutes in the refrigerator, the mixture was centrifuged and the supernatant was decanted. The residual solid was washed on a centrifuge with 2 x 30 mL of room temperature MTBE and dried overnight in a vacuum drying oven at 35 °C. The yield of the solid was 154.7 mg.

[1087] Analysis of the isolated solid by LC / MS indicated that the 10-mer was fully coupled to the tetramer to yield the TZP fragment 14-mer (amino acids 1 - 14).

[1088] Example 2: Fmoc-Thr(tBu)-Phe-Thr(tBu)-Ser(tBu)-OH

[1089]

[1090] Swelling of the resin: The resin (0.500 mmol) was added to a reactor and swollen with DMF (3 x 10 mL x 20 min).

[1091] Washing after de-Fmoc: After deprotection, the resin was washed with DMF (5 x 10 mL x 2 min).

[1092] Washing after coupling: After coupling, the resin was washed with DMF (5 x 10 mL x 2 min).

[1093] Washing and drying of the resin: After the final coupling or deprotection, the resin was washed with DMF (5 x 10 mL x 2 min), then with DCM (5 x 10 mL x 2 min), and then drained and dried to constant weight under a N2 atmosphere.

[1094] Preparation 33 procedure

[1095]

[1096] Four crystalline solid forms of the T-F-T-S tetramer were identified: Form A, Form B, Form C, and Form D. T-F-T-S Form A is a crystalline material produced from organic solvent / heptane mixtures such as IPA / heptane, EtOAc / heptane, MEK / heptane, iPrOAc / heptane, and THF / heptane. It represents a class of isostructural solvates. T-F-T-S Form B is a semi-disordered crystalline material produced from MTBE. T-F-T-S Form C is a semi-disordered crystalline material produced from ACN or 1:1 ACN / H2O. T-F-T-S Form D is crystalline and is a desolvated or partially desolvated material of T-F-T-S Form A with a variable amount of solvent in the unit cell.

[1097] XRPD patterns of the crystalline T-F-T-S tetramer were obtained on a Bruker D8 Endeavor X-ray powder diffractometer equipped with a CuKα source and a Linxeye detector, operating at 40 kV and 40 mA. The sample was scanned between 4 and 30 2θ°, with a step size of 0.009 2θ° and a scan rate of 0.25 seconds / step, and using a 0.3° primary slit opening and a 3.9° PSD opening. The powder was packed in a quartz or silicon sample holder, and a glass slide was used to obtain a smooth surface. Diffraction patterns of the crystal forms were collected at ambient temperature and relative humidity. Crystal peak positions were determined in MDI-Jade v7.9.9. In the field of crystallography, it is well known that for any given crystal form, the relative intensities of the diffraction peaks may vary due to preferred orientation caused by factors such as crystal morphology and habit. In the presence of a preferred orientation effect, the peak intensities are altered, but the characteristic peak positions of the polymorphs remain unchanged. See, e.g., The United States Pharmacopeia #23, National Formulary #18, pages 1843 - 1844, 1995. Additionally, in the field of crystallography, it is also well known that for any given crystal form, the angular peak positions may vary slightly. For example, the peak positions may shift due to changes in temperature during analysis of the sample, sample displacement, or the presence or absence of an internal standard. In this case, a peak position variability of ±0.2 2θ° is assumed to account for these potential variations without hindering the unambiguous identification of the indicated crystal forms. The crystal forms can be confirmed based on any unique combination of distinguishing peaks.

[1098] T-F-T-S Form A

[1099] In one experiment, Form A of T-F-T-S was prepared by adding 0.5 mL of a 1:1 volume / volume IPA / heptane mixture to 104.8 mg of amorphous T-F-T-S, followed by the addition of an additional 0.5 mL of heptane. The sample was stirred overnight under ambient conditions to produce a thin slurry. The sample was uncapped and left under ambient conditions for 3 days to evaporate the solvent. The resulting white solid was consistent with Form A of T-F-T-S.

[1100] In another experiment, Form A of T-F-T-S was prepared by stirring 62.1 mg of amorphous T-F-T-S in 300 μL of a 10:90 volume / volume MEK / heptane mixture at 5 °C. A thick white slurry was obtained. After 5 days, the sample was centrifuged under ambient conditions, the liquid phase was decanted, and the resulting white solid was consistent with Form A of T-F-T-S.

[1101] Samples of the prepared Form A of T-F-T-S were characterized by XRPD patterns using CuKα radiation as having the diffraction peaks (2-θ values) described in Table 4 below, and particularly having peaks at 4.3 and 12.8° 2-θ and one or more peaks selected from 5.8, 7.7 - 7.9, 10.0, 10.8 - 10.9, 11.3 - 11.4, 12.0 - 12.1, and 21.8° 2-θ; the tolerance for the diffraction angle was 0.2 degrees. A representative XRPD pattern of Form A of T-F-T-S is shown in Figure 2A in.

[1102] Table 4. X-Ray Powder Diffraction Peaks of Form A of T-F-T-S

[1103]

[1104] T-F-T-S Tetramer Form B

[1105] 2 × 0.2 mL of MTBE was added to 100.2 mg of amorphous T-F-T-S and the sample was capped and stirred / vortexed under ambient conditions to produce a thick white slurry. The wet solid from the slurry was consistent with Form B of T-F-T-S.

[1106] Samples of the prepared Form B of T-F-T-S were characterized by XRPD patterns using CuKα radiation as having the diffraction peaks (2-θ values) described in Table 5 below, and particularly having peaks at 5.7 and 7.3° 2-θ and one or more peaks selected from 5.1, 7.6, 9.5, and 12.4° 2-θ; the tolerance for the diffraction angle was 0.2 degrees. A representative XRPD pattern of Tetramer Form B of T-F-T-S is shown in Figure 2B in.

[1107] Table 5. X-Ray Powder Diffraction Peaks of Form B of T-F-T-S

[1108]

[1109] T-F-T-S Form C

[1110] In one experiment, 0.25 mL of 1:1 volume / volume ACN / H2O was added to 89.6 mg of amorphous T-F-T-S, and the sample was capped and stirred overnight under ambient conditions to produce a thick white slurry. The slurry was centrifuged for about 5 minutes under ambient conditions and the liquid phase was decanted; the resulting wet solid was consistent with T-F-T-S Form C.

[1111] In another experiment, 3 × 0.1 mL of ACN was added to 56.6 mg of amorphous T-F-T-S, and the sample was capped and stirred for about 3 hours under ambient conditions. The wet solid produced from the resulting thick white slurry was consistent with T-F-T-S Form C.

[1112] Samples of the prepared T-F-T-S Form C were characterized by XRPD patterns using CuKα radiation as having the diffraction peaks (2-θ values) described in Table 6 below, and specifically having a peak at 7.8° 2-θ and one or more peaks selected from 8.5, 12.0, 15.5, 20.2, and 23.3° 2-θ; the tolerance for the diffraction angle was 0.2 degrees. A representative XRPD pattern of T-F-T-S Form C is shown in Figure 2C in.

[1113] Table 6. X-ray powder diffraction peaks of T-F-T-S Form C

[1114]

[1115] T-F-T-S Form D

[1116] The solid of T-F-T-S Form A was air-dried for 7 days or longer under ambient conditions to obtain T-F-T-S Form D.

[1117] Samples of the prepared T-F-T-S Form D were characterized by XRPD patterns using CuKα radiation as having the diffraction peaks (2-θ values) described in Table 7 below, and specifically having peaks at 4.2 and 8.2 - 8.3° 2-θ and one or more peaks selected from 5.9, 7.7, 9.2, 10.2, 11.3, 13.8 - 13.9, 15.5 - 15.7, 17.1, and 18.5° 2-θ; the tolerance for the diffraction angle was 0.2 degrees. A representative XRPD pattern of T-F-T-S Form D is shown in Figure 2D in.

[1118] Table 7. X-ray powder diffraction peaks of T-F-T-S Form D

[1119]

[1120] Example 3: Pro-Ser(tBu)-Ser(tBu)-Gly-NH2

[1121]

[1122] Exact mass: 457.2900

[1123] Example 3 was prepared substantially by the procedure described in Example 4 below.

[1124] Swelling of the resin: The resin (0.500 mmol) was charged into a reactor and swollen with DMF (3 × 10 mL × 20 min).

[1125] Washing after de-Fmoc: After deprotection, the resin was washed with DMF (5 × 10 mL × 2 min).

[1126] Washing after coupling: After coupling, the resin was washed with DMF (5 × 10 mL × 2 min).

[1127] Washing and drying of the resin: After the final coupling or deprotection, the resin was washed with DMF (5 × 10 mL × 2 min), then with DCM (5 × 10 mL × 2 min), and drained and dried to constant weight under N2 atmosphere.

[1128] Seven crystalline solid forms of P-S-S-G-NH2 were identified, including Forms A to H of P-S-S-G-NH2. The polymorph diagram describing their relationship is shown in Figure 3 the scheme of.

[1129] Among these forms, P-S-S-G-NH2 Forms B and G are anhydrous / unsolvated, while C, D, E, F, and H are solvated. Forms A, E, and H are disordered crystalline materials.

[1130] The XRPD pattern of crystalline P-S-S-G-NH2 was obtained on a Bruker D8 Endeavor X-ray powder diffractometer equipped with CuKα A source and a Linxeye detector were operated at 40 kV and 40 mA. The sample was scanned between 4 and 42 2θ°, with a step size of 0.009 2θ°, a scan rate of 0.5 seconds / step, and using a 0.3° primary slit opening and a 3.9° PSD opening. In some cases, the sample was scanned between 4 and 30 2θ° at a scan rate of 0.25 seconds / step. The powder was packed onto a quartz or silicon sample holder, and a glass slide was used to obtain a smooth surface. Diffraction patterns of the crystal form were collected at ambient temperature and relative humidity. Crystal peak positions were determined in MDI-Jade v7.9.9. In the field of crystallography, it is well known that for any given crystal form, the relative intensities of the diffraction peaks may vary due to preferred orientation caused by factors such as crystal morphology and habit. In the presence of a preferred orientation effect, the peak intensities are altered, but the characteristic peak positions of the polymorphs do not change. See, for example, The United States Pharmacopeia #23, National Formulary #18, pages 1843 - 1844, 1995. Additionally, in the field of crystallography, it is also well known that for any given crystal form, the angular peak positions may vary slightly. For example, the peak positions can be shifted due to changes in temperature during analysis of the sample, sample displacement, or the presence or absence of an internal standard. In this case, a peak position variability of ±0.2 2θ° was assumed to account for these potential variations without preventing the unambiguous identification of the indicated crystal form. The crystal form can be confirmed based on any unique combination of distinguishing peaks.

[1131] P-S-S-G-NH2 Form A

[1132] 12.7549 g of the solid-phase peptide synthesis resin for P-S-S-G-NH2 tetramer was loaded into a 150 mL sintered reactor equipped with an overhead stirrer. 128 mL of a 5% TFA / DCM cleavage mixture (6.4 mL TFA, 121.6 mL DCM) was loaded into the reactor and the resulting solution was stirred for 30 minutes. The reactor was emptied and washed with DCM (2 × 120 mL). MTBE was added to the filtrate to precipitate the tetramer. The resulting precipitate was filtered through a Buchner funnel and allowed to air dry under vacuum suction overnight, and then dried in a vacuum drying oven at 35 °C overnight to remove residual solvent. The resulting solid was consistent with P-S-S-G-NH2 Form A.

[1133] The prepared sample of P-S-S-G-NH2 Form A was characterized by XRPD patterns using CuKα radiation as having the diffraction peaks (2-θ values) described in Table 8 below, and particularly having peaks at 7.0 and 8.0° 2-θ and one or more peaks selected from 10.3, 14.1, 16.7, and 19.0° 2-θ; the tolerance for the diffraction angle was 0.2 degrees. A representative XRPD pattern of P-S-S-G-NH2 Form A is shown in Figure 4A in.

[1134] Table 8. X-ray powder diffraction peaks of P-S-S-G-NH2 Form A

[1135]

[1136]

[1137] P-S-S-G-NH2 Form B

[1138] In one experiment, 80.9 mg of the solid of P-S-S-G-NH2 Form A was stirred in 0.8 mL of ACN under ambient conditions to produce a white suspension. After 8 days, the slurry was separated by centrifuging the mixture for 5 minutes using a centrifuge tube filter under ambient conditions. The resulting white solid was consistent with P-S-S-G-NH2 Form B.

[1139] In another experiment, 5.3 mg of the solid of P-S-S-G-NH2 Form A was added to a clean TGA pan, heated to 150 °C on the TGA and held at that temperature for 60 minutes. The resulting off-white solid was consistent with P-S-S-G-NH2 Form B.

[1140] In yet another experiment, 7.0 mg of the solid of P-S-S-G-NH2 Form C was added to a clean TGA pan, heated to 165 °C on the TGA and held at that temperature for 5 minutes. The resulting white solid was consistent with P-S-S-G-NH2 Form B.

[1141] The prepared sample of P-S-S-G-NH2 Form B was characterized by XRPD patterns using CuKα radiation as having the diffraction peaks (2-θ values) described in Table 9 below, and particularly having a peak at 9.0° 2-θ and one or more peaks selected from 5.7, 9.9, 16.2, 18.1 and 18.4° 2-θ; the tolerance of the diffraction angle was 0.2 degrees. A representative XRPD pattern of P-S-S-G-NH2 Form B is shown in Figure 4B in.

[1142] Table 9. X-ray powder diffraction peaks of P-S-S-G-NH2 Form B

[1143]

[1144]

[1145] P-S-S-G-NH2 Form C

[1146] In one experiment, 83.6 mg of the solid of P-S-S-G-NH2 Form A was stirred in 0.8 mL of wet EtOAc under ambient conditions to produce a white suspension. After 8 days, the slurry was separated by centrifuging the mixture for 5 minutes using a centrifuge tube filter under ambient conditions. The resulting white solid was consistent with P-S-S-G-NH2 Form C.

[1147] In another experiment, a mixture containing P-S-S-G-NH2 Forms C and D was air-dried overnight under ambient conditions to produce a single phase of P-S-S-G-NH2 Form C.

[1148] The prepared sample of P-S-S-G-NH2 Form C was characterized by XRPD patterns using CuKα radiation as having the diffraction peaks (2-θ values) described in Table 10 below, and particularly having peaks at 5.6 and 10.5° 2-θ and one or more peaks selected from 11.9, 13.3, and 21.1° 2-θ; the tolerance of the diffraction angle was 0.2 degrees. A representative XRPD pattern of P-S-S-G-NH2 Form C is shown in Figure 4C in.

[1149] Table 10. X-ray powder diffraction peaks of P-S-S-G-NH2 Form C

[1150]

[1151] P-S-S-G-NH2 Form D

[1152] 76.0 mg of the solid of P-S-S-G-NH2 Form A was stirred in 0.8 mL of EtOAc under ambient conditions to produce a thick white slurry. Another 0.5 mL of EtOAc was added the next day, and the sample was stirred for an additional 7 days under ambient conditions. The mixture was then transferred to a centrifuge tube filter and centrifuged for 5 minutes under ambient conditions, and the solid was air-dried under ambient conditions for about 4 hours. A mixture of a white solid and a translucent mass was obtained. As determined by XRPD, the sample consisted of Forms C and D.

[1153] The prepared sample of P-S-S-G-NH2 Form D was characterized by XRPD patterns using CuKα radiation as having the diffraction peaks (2-θ values) described in Table 11 below, and particularly having a peak at 4.9° 2-θ and one or more peaks selected from 10.7, 14.8, and 20.3° 2-θ; the tolerance of the diffraction angle was 0.2 degrees. A representative XRPD pattern of P-S-S-G-NH2 Form D is shown in Figure 4D in.

[1154] Table 11. X-ray powder diffraction peaks of P-S-S-G-NH2 Form D

[1155]

[1156] P-S-S-G-NH2 Form E

[1157] 66.9 mg of the solid of P-S-S-G-NH2 Form A was stirred in 0.8 mL of MeOAc under ambient conditions to produce a white suspension. After 8 days, the slurry was separated by centrifuging the mixture for 5 minutes using a centrifuge tube filter under ambient conditions. The solid was air-dried under ambient conditions for about 4 hours to produce a mixture of a white solid and translucent chunks, which showed an XRPD pattern consistent with P-S-S-G-NH2 Form E.

[1158] The prepared sample of P-S-S-G-NH2 Form E was characterized by XRPD pattern using CuKα radiation as having the diffraction peaks (2-θ values) described in Table 12 below, and particularly having peaks at 13.1 and 17.5° 2-θ and one or more peaks selected from 5.9, 10.5, 10.9, and 15.9° 2-θ; the tolerance of the diffraction angle was 0.2 degrees. A representative XRPD pattern of P-S-S-G-NH2 Form E is shown in Figure 4E in.

[1159] Table 12. X-ray powder diffraction peaks of P-S-S-G-NH2 Form E

[1160]

[1161]

[1162] P-S-S-G-NH2 Form F

[1163] 71.1 mg of the solid of P-S-S-G-NH2 Form A was stirred in 0.8 mL of THF under ambient conditions to produce a white suspension. After 8 days, the slurry was separated by centrifuging the mixture for 5 minutes using a centrifuge tube filter under ambient conditions, and the material was air-dried under ambient conditions for about 4 hours. The resulting white solid was consistent with P-S-S-G-NH2 Form F.

[1164] The prepared sample of P-S-S-G-NH2 Form F was characterized by XRPD pattern using CuKα radiation as having the diffraction peaks (2-θ values) described in Table 13 below, and particularly having a peak at 7.8° 2-θ and one or more peaks selected from 11.3, 11.5, 15.4, and 15.6° 2-θ; the tolerance of the diffraction angle was 0.2 degrees. A representative XRPD pattern of P-S-S-G-NH2 Form F is shown in Figure 4F in.

[1165] Table 13. X-ray powder diffraction peaks of P-S-S-G-NH2 Form F

[1166]

[1167] P-S-S-G-NH2 Form G

[1168] 12.2 mg of the solid of P-S-S-G-NH2 Form F was added to a clean TGA pan, heated to 125 °C on the TGA and held at that temperature for 5 minutes. The resulting white solid was consistent with P-S-S-G-NH2 Form G.

[1169] The prepared sample of P-S-S-G-NH2 Form G was characterized by XRPD patterns using CuKα radiation as having diffraction peaks (2-θ values) described in Table 14 below, and particularly having peaks at 10.0 and 12.5° 2-θ and one or more peaks selected from 8.1, 14.7, 18.8 and 22.4° 2-θ; the tolerance of the diffraction angle was 0.2 degrees. A representative XRPD pattern of P-S-S-G-NH2 Form G is shown in Figure 4G in.

[1170] Table 14. X-ray powder diffraction peaks of P-S-S-G-NH2 Form G

[1171]

[1172] P-S-S-G-NH2 Form H

[1173] 71.6 mg of the solid of P-S-S-G-NH2 Form A was stirred in 0.8 mL of IPA under ambient conditions to produce a thick white slurry. Another 0.5 mL of IPA was added the next day, and the sample was stirred for an additional 7 days under ambient conditions. The mixture was then transferred to a centrifuge tube filter and centrifuged for 5 minutes under ambient conditions, and the solid was air-dried for about 4 hours under ambient conditions. A mixture of a white solid and translucent chunks was obtained, which showed an XRPD pattern consistent with P-S-S-G-NH2 Form H.

[1174] The prepared sample of P-S-S-G-NH2 Form H was characterized by XRPD patterns using CuKα radiation as having diffraction peaks (2-θ values) described in Table 15 below, and particularly having peaks at 10.8 and 21.1° 2-θ and one or more peaks selected from 5.6, 10.5, 11.9 and 15.4° 2-θ; the tolerance of the diffraction angle was 0.2 degrees. A representative XRPD pattern of P-S-S-G-NH2 Form H is shown in Figure 4H in.

[1175] Table 15. X-ray powder diffraction peaks of the P-S-S-G-NH2 form H

[1176]

[1177] Example 4: Gly-Pro-Ser(tBu)-Ser(tBu)-Gly-NH2

[1178]

[1179] Swelling of the resin: The resin (0.500 mmol) was charged into a reactor and swollen with DMF (3 × 10 mL × 20 min).

[1180] Washing after de-Fmoc: After deprotection, the resin was washed with DMF (5 × 10 mL × 2 min).

[1181] Washing after coupling: After coupling, the resin was washed with DMF (5 × 10 mL × 2 min).

[1182] Washing and drying of the resin: After the final coupling or deprotection, the resin was washed with DMF (5 × 10 mL × 2 min), then washed with DCM (5 × 10 mL × 2 min), and drained and dried to constant weight under a N2 atmosphere.

[1183] Preparation 1 procedure

[1184]

[1185] Cleavage from the resin:

[1186] 5% TFA / DCM (10 volumes) was added to the resin and the reactor was stirred for 30 minutes. The reactor was emptied and the resin was washed with DCM (2 × 5 volumes). The filtrate was added to pre-cooled MTBE: heptane (1:1, 10 volumes relative to the cleavage solution), and then centrifuged (3000 rpm × 10 min). The supernatant was discarded and fresh cold MTBE: heptane (5 volumes) was added and the mixture was centrifuged (3000 rpm × 5 min). The supernatant was discarded and the process was repeated one more time with fresh MTBE: heptane. The supernatant was discarded and the resulting material was placed in a vacuum drying oven at 34 °C for 14 hours to give Preparation 1.

[1187] Two crystalline solid forms of the G-P-S-S-G-NH2 pentamer were identified, including the G-P-S-S-G-NH2 form A and form B. The G-P-S-S-G-NH2 form A is a crystalline solvate that is physically unstable and readily converts to form B during isolation or upon air drying. The G-P-S-S-G-NH2 form B is a crystalline anhydrous / unsolvated form.

[1188] The XRPD pattern of crystalline G-P-S-S-G-NH2 pentamer was obtained on a Bruker D8 Endeavor X-ray powder diffractometer equipped with a CuKα source and a Linxeye detector, operating at 40 kV and 40 mA. The sample was scanned between 4 and 42 2θ°, with a step size of 0.009 2θ° and a scan rate of 0.5 seconds / step, and using a 0.3° primary slit opening and a 3.9° PSD opening. For the case of G-P-S-S-G-NH2 Form A, the sample was scanned between 4 and 25 2θ°, with a scan rate of 0.1 seconds / step. The powder was packed in a quartz or silicon sample holder, and a glass slide was used to obtain a smooth surface. The diffraction pattern of the crystal form was collected at ambient temperature and relative humidity. The crystal peak positions were determined in MDI-Jade v7.9.9. It is well known in the field of crystallography that for any given crystal form, the relative intensities of the diffraction peaks may vary due to preferred orientation caused by factors such as crystal morphology and habit. In the presence of a preferred orientation effect, the peak intensities will be altered, but the characteristic peak positions of the polymorphs do not change. See, for example, The United States Pharmacopeia #23, National Formulary #18, pages 1843-1844, 1995. In addition, it is also well known in the field of crystallography that for any given crystal form, the angular peak positions may vary slightly. For example, the peak positions may be shifted due to changes in temperature during analysis of the sample, sample displacement, or the presence or absence of an internal standard. In this case, a peak position variability of ±0.2 2θ° is assumed to account for these potential variations without hindering the clear identification of the indicated crystal form. The crystal form can be confirmed based on any unique combination of distinguishing peaks.

[1189] G-P-S-S-G-NH2 Form A

[1190] G-P-S-S-G-NH2 Form A was prepared in methanol (MeOH) / tetrahydrofuran (THF). At ambient temperature, 71.0 mg of amorphous G-P-S-S-G-NH2 was dissolved in 0.2 mL of MeOH; 3 × 0.2 mL of THF was added to the solution and the sample was stirred overnight under ambient conditions, yielding a soft white solid that was consistent with G-P-S-S-G-NH2 Form A when analyzed in the wet state.

[1191] The prepared sample of G-P-S-S-G-NH2 Form A was characterized by XRPD pattern using CuKα radiation as having the diffraction peaks (2-θ values) described in Table 16 below, and particularly having a peak at 4.3° 2-θ and one or more peaks selected from 5.1, 6.1, 8.0, 10.1, and 18.7° 2-θ; the tolerance for the diffraction angle is 0.2 degrees. A representative XRPD pattern of G-P-S-S-G-NH2 Form A is shown inFigure 5A in

[1192] Table 16. X-ray powder diffraction peaks of G-P-S-S-G-NH2 form A

[1193]

[1194] G-P-S-S-G-NH2 form B

[1195] In the above example of G-P-S-S-G-NH2 form A, an additional 3 × 0.2 mL of THF and 1 × 0.2 mL of MeOH were added to the sample; the white slurry was stirred for 9 days under ambient conditions and then separated by centrifugation using a centrifuge tube filter. The resulting solid was consistent with G-P-S-S-G-NH2 form B and remained in form B after drying in vacuo at 32 - 33 °C for 1 day.

[1196] The prepared sample of G-P-S-S-G-NH2 form B was characterized by XRPD patterns using CuKα radiation as having the diffraction peaks (2-θ values) described in Table 17 below, and particularly having peaks at 5.2 and 9.0° 2-θ and one or more peaks selected from 6.7, 10.0, 10.3, 16.4, 17.8, 18.3, and 19.4° 2-θ; the tolerance for the diffraction angle was 0.2 degrees. A representative XRPD pattern of G-P-S-S-G-NH2 form B is shown in Figure 5B in

[1197] Table 17. X-ray powder diffraction peaks of G-P-S-S-G-NH2 form B

[1198]

[1199] Example 5 Fmoc-Thr(tBu)-Phe-Thr(tBu)-Ser(tBu)-Asp(OtBu)-OH

[1200]

[1201] Swelling of the resin: The resin (0.500 mmol) was loaded into a reactor and swollen with DMF (3 × 10 mL × 20 min).

[1202] Washing after de-Fmoc: After deprotection, the resin was washed with DMF (5 × 10 mL × 2 min).

[1203] Washing after coupling: After coupling, the resin was washed with DMF (5 × 10 mL × 2 min).

[1204] Washing and Drying of Resin: After the final coupling or deprotection, the resin was washed with DMF (5 × 10 mL × 2 min), then washed with DCM (5 × 10 mL × 2 min), and drained and dried to constant weight under a N2 atmosphere.

[1205] Preparation 35 Procedure

[1206]

[1207] Two crystalline solid forms of the T-F-T-S-D pentamer were identified, including T-F-T-S-D Form A and Form B. T-F-T-S-D Form B is a semi-disordered crystalline material observed under various solvent conditions. It represents a class of isostructural solvates. T-F-T-S-D Form A is also a semi-disordered crystalline material that is produced by the desolvation or partial desolvation of T-F-T-S-D Form B and thus represents another class of desolvated or partially desolvated isostructural forms.

[1208] XRPD patterns of crystalline T-F-T-S-D pentamer were obtained on a Bruker D8 Endeavor X-ray powder diffractometer equipped with a CuKα source and a Linxeye detector, operating at 40 kV and 40 mA. The sample was scanned between 4 and 30 2θ°, with a step size of 0.009 2θ° and a scan rate of 0.25 seconds / step, and using a 0.3° primary slit opening and a 3.9° PSD opening. In some cases, the scan range was 4 and 25 2θ°, with a step size of 0.0092θ° and a scan rate of 0.1 seconds / step. The sample was filled in a quartz or silicon sample holder, and a glass slide was used to obtain a smooth surface. Diffraction patterns of the crystal forms were collected at ambient temperature and relative humidity. Crystal peak positions were determined in MDI-Jade v7.9.9. It is well known in the field of crystallography that for any given crystal form, the relative intensities of diffraction peaks may vary due to preferred orientation caused by factors such as crystal morphology and habit. In the presence of a preferred orientation effect, the peak intensities will change, but the characteristic peak positions of the polymorphs do not change. See, for example, The United States Pharmacopeia #23, National Formulary #18, pages 1843-1844, 1995. Additionally, it is well known in the field of crystallography that for any given crystal form, the angular peak positions may vary slightly. For example, the peak positions may shift due to changes in temperature during analysis of the sample, sample displacement, or the presence or absence of an internal standard. In this case, a peak position variability of ±0.2 2θ° was assumed to account for these potential variations without preventing the clear identification of the indicated crystal forms. Crystal forms can be confirmed based on any unique combination of distinguishing peaks.

[1209] T-F-T-S-D Form A

[1210] In one experiment, 171.5 mg of amorphous T-F-T-S-D pentamer was dissolved in 0.7 mL of EtOAc under ambient conditions; with stirring, 0.7 mL of heptane was slowly added to the sample and a precipitate formed immediately. After adding an additional 0.7 mL of heptane, the sample was stirred for 4 days under ambient conditions to produce a white slurry. The white solid isolated from the sample was consistent with T-F-T-S-D Form A.

[1211] In another experiment, 45.7 mg of amorphous T-F-T-S-D pentamer was dissolved in 100 μL of MEK to form a clear solution, and 200 μL of n-propyl ether was added to the solution, and then the sample was stirred for 4 days under ambient conditions to produce a white slurry. T-F-T-S-D Form A was produced by taking a wet aliquot from the slurry and air-drying it for 1 day under ambient conditions.

[1212] The samples of prepared T-F-T-S-D Form A were characterized by XRPD patterns using CuKα radiation as having the diffraction peaks (2-θ values) described in Table 18 below, and specifically having a peak at 6.7 - 7.1° 2-θ and one or more peaks selected from 5.8 - 6.1 and 8.8 - 9.0° 2-θ; the tolerance for the diffraction angle was 0.2 degrees. Representative XRPD patterns of T-F-T-S-D Form A are shown in Figure 6A in.

[1213] Table 18. X-ray powder diffraction peaks of T-F-T-S-D Form A

[1214]

[1215] T-F-T-S-D Form B

[1216] In one experiment, 195.8 mg of amorphous T-F-T-S-D pentamer was dissolved in 0.4 mL of THF under ambient conditions; with stirring, 0.4 mL of heptane was slowly added to the sample and a precipitate formed immediately. The sample was stirred for 4 days under ambient conditions and a white slurry was observed. The wet solid from the slurry was consistent with T-F-T-S-D Form B.

[1217] In another experiment, 45.7 mg of amorphous T-F-T-S-D pentamer was dissolved in 100 μL of MeOAc to form a clear solution, and 100 μL of heptane was added to the solution to immediately produce a white precipitate. The sample was stirred for 4 days under ambient conditions, and the wet sample from the resulting white slurry was consistent with T-F-T-S-D Form B.

[1218] The prepared sample of T-F-T-S-D Form B was characterized by XRPD patterns using CuKα radiation as having the diffraction peaks (2-θ values) described in Table 19 below, and specifically having a peak at 5.0 - 5.2° 2-θ and one or more peaks selected from 5.3 - 5.4, 5.7 - 6.0, 7.6 - 7.9, and 8.7 - 9.1° 2-θ; the tolerance of the diffraction angle was 0.2 degrees. A representative XRPD pattern of T-F-T-S-D Form B is shown in Figure 6B as follows.

[1219] Table 19. X-ray powder diffraction peaks of T-F-T-S-D Form B

[1220]

[1221]

[1222] Example 6: Boc-Tyr(tBu)-Aib-Gln(trt)-Gly-OH

[1223]

[1224] Conventional SPPS

[1225] A tetramer was synthesized by conventional SPPS.

[1226] Fmoc-Gly-OH was loaded onto CTC resin

[1227] The CTC resin was swollen with DMF, and Fmoc-Gly-OH was loaded onto the CTC resin by using 1.5 molar equivalents of Gly and 4.0 equivalents of DIEA (relative to the loading factor of the CTC resin). The loading was carried out at 25 °C for 4 hours, and after washing the resin, the unreacted sites on the resin were covered with a solution of 0.5 volume of MeOH, 1.6 volumes of DIEA, and 8 volumes of DMF (relative to the weight of the resin used).

[1228] Coupled with Fmoc-L-Gln(trt)-OH

[1229] The Fmoc group was removed by treating with 10 volumes of 20% piperidine / DMF for one hour, and the resin was washed with isopropyl acetate until the residual piperidine was less than 500 ppm. A solution of Fmoc-L-Gln(trt)-OH (2.0 equivalents) and Oxyma (2.0 equivalents) in 5.3 volumes of DMF was prepared. DIC (2.2 equivalents) was added, and the amino acid was allowed to preactivate for 90 minutes at 20 °C. The activated ester solution was added to the resin, and the reaction mixture was stirred at 20 °C for 12 hours and then drained. The resin was washed with isopropyl acetate and subjected to the next coupling treatment.

[1230] Coupling with Fmoc-Aib-OH

[1231] The Fmoc group was removed by treating with 10 volumes of 20% piperidine / DMF for one hour, and the resin was washed with isopropyl acetate until the residual piperidine was less than 500 ppm. A solution of Fmoc-Aib-OH (2.0 equivalents) and Oxyma (2.0 equivalents) in 5.3 volumes of DMF was prepared. DIC (2.2 equivalents) was added, and the amino acid was allowed to preactivate for 15 minutes at 20 °C. The activated ester solution was added to the resin, and the reaction mixture was stirred at 20 °C for 12 hours and then drained. The resin was washed with isopropyl acetate and subjected to the next coupling treatment.

[1232] Coupling with Boc-L-Tyr(tBu)-OH

[1233] The Fmoc group was removed by treating with 10 volumes of 20% piperidine / DMF for one hour, and the resin was washed with isopropyl acetate until the residual piperidine was less than 500 ppm. A solution of Boc-L-Tyr(tBu)-OH (2.0 equivalents) and Oxyma (2.0 equivalents) in 5.3 volumes of DMF was prepared. DIC (2.2 equivalents) was added, and the amino acid was allowed to preactivate for 15 minutes at 20 °C. The activated ester solution was added to the resin, and the reaction mixture was stirred at 20 °C for 12 hours and then drained. The resin was washed with isopropyl acetate and dried to constant weight at 35 °C and under vacuum.

[1234] Cleavage

[1235] All cleavage operations were carried out at 15 - 25 °C; the tetramers on the resin material were placed in a cleavage filtration reactor; 5 L of DCM / kg resin was added, the material was stirred for no less than 10 min, and the solvent was drained to waste; then 5 L of a 0.5% (v / v) solution of TFA in DCM / kg resin was added to the cleavage filtration reactor, and the mixture was stirred for no more than 60 min. The product solution was drained into a product collection container and neutralized with 1 equivalent of pyridine; then 5 L of a 0.5% (v / v) solution of TFA in DCM / kg resin was added to the cleavage filtration reactor and stirred for no more than 60 min. The product solution was drained into a product collection container and neutralized with 1 equivalent of pyridine. Then 5 L of DCM / kg was added to the cleavage filtration reactor and stirred for no more than 10 min. The product solution was drained into a product collection container and 5 L of DCM / kg was added to the cleavage filtration reactor and stirred for no more than 10 min. The product solution was drained into a product collection container.

[1236] Workup

[1237] Concentrate the product solution to 5 L / kg of resin at a pressure not exceeding 0.4 bar and a jacket temperature of 15 - 25 °C; add 10 L of pure water / kg of resin and stir the mixture for not less than 30 min, and allow it to settle until clear. Collect the bottom organic layer and conduct Karl Fischer (KF) titration, as well as the specifications during the processes of pyridine and TFA. If KF is greater than 0.35 wt%, add 0.4 kg of Na2SO4 / kg of resin for re-slurry drying. If pyridine is greater than 0.2 wt%, add the corresponding equivalent of a 0.5% solution of TFA in DCM to titrate the excess pyridine. Stir the mixture for not less than 10 min, add 10 L of water / kg of resin, and stir the mixture for not less than 30 min. Collect the organic layer. Once the in-process specifications are passed, add 2 L of amyl acetate / kg of resin, apply a 40 °C jacket and 0.1 bar, and concentrate the mixture to 2.5 L of solution / kg of resin. Check if the solution IPC on DCM is less than 7 wt%; add another 2 L of amyl acetate / kg of resin.

[1238] LPPS

[1239] Alternatively, synthesize the tetramer via LPPS.

[1240] Step 1:

[1241]

[1242] Aib protection -- In a container, charge H-Aib-OH (1.3 equivalents relative to Boc-Tyr(But)-OH) and MeCN (3V), then slowly add bis(trimethylsilyl)acetamide (BSA) (1 equivalent). Stir the mixture at 20 - 30 °C for 16 h.

[1243] Coupling reaction -- In another container, charge Boc-Tyr(But)-OH, MeCN (7V), and 2,6-dimethylpyridine (3 equivalents). Set the container temperature to -25 °C. Stir the mixture for 0.5 h. Slowly charge PivCl (1.1 equivalents) into the container. Stir the mixture for 2 h. Analyze the sample for complete activation. Charge the contents of the first container (Aib protected) into this reaction container. Stir at -25 °C for 16 h. Analyze the sample at the end of the reaction.

[1244] Quenching and work-up– Add acetic acid (2 eq) and water (10V). Concentrate to remove MeCN. Extract twice with EtOAc (10V). Wash the organic layer with 5% citric acid (10V) and water (10V). Concentrate the organic layer to 2 volumes. Slowly add heptane (16V), then filter the solid. Redissolve the solid in EtOAc (6V) and heat to 40 °C. Slowly add heptane (24V), then slowly cool to 20 °C and mix for 16 h. Filter and dry the wet cake under vacuum at 35 - 45 °C for 24 h.

[1245] Step 2:

[1246]

[1247] Coupling reaction -- Add a solution of the dimer intermediate (C18070201 - B) in THF (3V) and NMM (1.35 eq) to a solution of IBCF (1.05 eq) in THF (7V) at 0 °C. Stir at 0 °C for 4 - 6 h. Check the sample for complete activation. In another reaction vessel, dissolve H - Gln(Trt)-OH (1.4 eq) in THF (10V) and water (3V) and stir for 0.5 h, then add to the solution containing the dimer intermediate B at 0 °C. Add DIPEA (3.0 eq) and stir at 0 °C for 4 - 6 h. Raise the temperature to 20 °C over 3 - 4 h, then stir for 12 - 20 h. Check the sample for the end of the reaction. Concentrate to 1 - 2V under vacuum below 45 °C. Add MTBE (20V), then wash the organic layer 4 times with a 10:1 solution of 5% aqueous KHSO4:DMF (15V). Wash the organic layer 4 times with a 10:1 solution of 5% aqueous Na2CO3:DMF (10:1). Wash the organic layer once with 5% aqueous KHSO4 (10V). Concentrate to 1 - 2V.

[1248] Salt formation purification – Add EtOAc (2.67V) to the solution and heat to 50 °C. Add (1S)-1 - phenylpropan - 1 - amine (1.5 eq), then slowly add MeCN (5.33V). Stir at 50 °C for 2 h, then slowly cool to 25 °C. Filter and wash the cake with 1:2 EtOAc:MeCN (1V). Add MTBE (20V), then wash twice with 5% KHSO4. Concentrate to dryness and sample for analysis. If necessary, repeat the salt - formation purification.

[1249] Separation – Add MTBE (1.2V) to the solid. Add heptane (6V) and stir at 25 °C for 16 h. Filter and wash the wet cake with heptane (2V). Dry the wet cake at 40 °C for 18 h.

[1250] Step 3:

[1251]

[1252] Add the trimer intermediate (C18070201-EA), H-Gly-OBzl (1.3 equivalents), and MeCN (10V) to a reaction vessel and cool the temperature to -20°C. Add 2,6-dimethylpyridine (3.0 equivalents) and COMU (1.3 equivalents) and stir at -20°C for 2 - 4 hours. Analyze the sample to check the end of the reaction. Concentrate to 1V at below 46°C. Add EtOAc (5V) and stir for 0.5 - 1 hour. Add MTBE (5V), then filter the mixture. Wash the filter cake with 1:1 EtOAc:MTBE (5V). Wash the filtrate 4 times with 5% NaHCO3 (10V), 4 times with KHSO4 (10V), and then 1 time with water (10V). Concentrate the organic layer to 1 - 2V at below 45°C. Add DMF (2.5V) and stir at 15 - 20°C to form a clear solution. Slowly add water (7.5V). Stir the mixture at 15 - 20°C for 2 - 6 hours. Filter and wash the filter cake with water (2 - 3V). Repulp the filter cake with water (10V) at 15 - 20°C for 2 - 6 hours and filter. Wash the filter cake with water (2 - 3V), then dry at 45°C for 16 - 48 hours. Check for residual DMF and water. If necessary, repulp with water again or further dry.

[1253] Step 4:

[1254]

[1255] Benzyl deprotection – Add the tetramer ester intermediate (C18070201-CA) and IPA (10V) to a reaction vessel. Add Pd / C (0.1x, 50 wt%) to the reaction vessel and exchange the atmosphere with argon 3 times. Exchange the atmosphere with hydrogen 3 times. Pressurize the vessel with hydrogen to 45 psi and heat the reactor to 40°C. Stir the reactants at 45 psi and 40°C for 16 - 20 hours. Take a sample for analysis. Cool the reaction vessel to 20 - 30°C and exchange the atmosphere with argon 3 times. Filter the mixture and wash the wet filter cake (Pd / C) with IPA (2V). Concentrate the filtrate to 1V at below 45°C.

[1256] Crystallization– Charge amyl acetate (5V) and then concentrate to 1V below 45 °C. Repeat this process three times in total. Charge amyl acetate (5V) and stir at 20 °C for 0.5 - 1 hour. Charge heptane (1V) over 1 hour. Stir the mixture at 20 °C for 3 - 5 hours. Apply a heat cycle (heat to 35 °C over 1 hour, stir for 3 - 5 hours, cool to 20 °C over 1 hour, stir at 20 °C for 3 - 5 hours) twice. Charge 5V heptane over 1 hour. Stir at 20 °C for 3 - 5 hours. Filter the solid and wash the wet cake with heptane (2V). Dry the wet cake under vacuum at 40 - 50 °C for 16 - 24 hours. Take a sample and determine if repulping is needed.

[1257] Crystallization

[1258] After solvent exchange by distillation, the tetramer is in 5 volumes of amyl acetate (L / kg resin, tetramer concentration 80 - 100 mg / mL). Hold the solution at 20 °C for 12 hours for primary nucleation. If solids are observed, the mixture goes into a heat cycle. If no solids are observed, cool the mixture to 5 °C and hold for 12 hours. If solids are observed, the mixture goes into a heat cycle. If no solids are observed, add 1 volume of heptane and hold the mixture for 12 hours. If solids are observed, the mixture goes into a heat cycle. If no solids are observed, add 1 volume of heptane and repeat the process.

[1259] The heat cycle is used to convert the amorphous to the crystalline form and grow the crystalline particles. Heat the mixture to 30 °C, hold for 1 hour, then cool to 20 °C and hold for 1 hour. Repeat the heat cycle five times.

[1260] After the heat cycle, add 5 volumes of heptane to reduce solubility and increase yield. Then, filter the slurry. Wash it once with 5 volumes of 1:1 heptane:amyl acetate to remove impurities. Wash it twice with 5 volumes of heptane in the repulping wash liquor to remove amyl acetate. Finally, dry the solid at 50 °C.

[1261] Two solid forms of the Y-Aib-Q-G tetramer were identified, including Form A and Form B of Y-Aib-Q-G. Form A of Y-Aib-Q-G is the crystalline form. The solvated form is initially produced from amyl acetate or a mixture containing amyl acetate (such as amyl acetate / ETBE, amyl acetate / TAME, amyl acetate / heptane, etc.).

[1262] Form A of Y-Aib-Q-G represents a class of isostructural solvates and can also be generated from other solvent conditions (such as EtOAc and 2-Me THF / TAME).

[1263] Y-Aib-Q-G Form B is a semi-disordered crystalline material that is produced by the desolvation or partial desolvation of Y-Aib-Q-G Form A and thus represents another class of desolvated or partially desolvated polymorphic forms.

[1264] Preparation of Y-Aib-Q-G Form A

[1265] Y-Aib-Q-G Form A was obtained by adding 1 mL of amyl acetate to 210.0 mg of amorphous Y-Aib-Q-G tetramer. The sample was stirred under ambient conditions to produce a clear solution. 3 mL of ETBE (tert-butyl ethyl ether) was added to the solution, and the sample was capped and stirred under ambient conditions. After the sample had been stirred for 2 days, a thick white slurry was obtained and an additional 2 mL of ETBE was added to the slurry. The sample was stirred for an additional 3 days under ambient conditions, and the wet sample from the resulting white slurry was consistent with Y-Aib-Q-G Form A.

[1266] Y-Aib-Q-G Form A was also obtained by dissolving 55.5 mg of amorphous Y-Aib-Q-G tetramer in 250 μL of amyl acetate. 0.5 mL of heptane was added to the solution to produce a white suspension. The sample was stirred in a capped vial under ambient conditions for 1 day and a white slurry was obtained. The XRPD of the wet sample from the slurry was consistent with Y-Aib-Q-G Form A.

[1267] Preparation of Y-Aib-Q-G Form B

[1268] Form B solid was obtained by drying Y-Aib-Q-G Form A. The wet solid from the first example above was separated by vacuum filtration, and the resulting material was rinsed on the filter with 0.5 mL of ETBE, air-dried on the filter under continuous vacuum for approximately 5 minutes, collected, and then dried under vacuum at approximately 30 °C for 1 day. The XRPD of the resulting white solid was consistent with Y-Aib-Q-G Form B.

[1269] The XRPD pattern of the crystalline Y-Aib-Q-G tetramer was obtained on a Bruker D8 Endeavor X-ray powder diffractometer equipped with CuKα A source and a Linxeye detector were used, operating at 40 kV and 40 mA. The sample was scanned between 4 and 30 2θ°, with a step size of 0.009 2θ°, a scan rate of 0.25 seconds per step, and using a 0.3° primary slit opening and a 3.9° PSD opening. The powder was filled onto a quartz or silicon sample holder, and a glass slide was used to obtain a smooth surface. Diffraction patterns of the crystal form were collected at ambient temperature and relative humidity. The crystal peak positions were determined in MDI-Jade v7.9.9. In the field of crystallography, it is well known that for any given crystal form, the relative intensities of the diffraction peaks may vary due to preferred orientation caused by factors such as crystal morphology and habit. In the presence of a preferred orientation effect, the peak intensities are altered, but the characteristic peak positions of the polymorphs remain unchanged. See, for example, The United States Pharmacopeia #23, National Formulary #18, pages 1843-1844, 1995. Additionally, in the field of crystallography, it is also well known that for any given crystal form, the angular peak positions may vary slightly. For example, the peak positions may shift due to changes in temperature during analysis of the sample, sample displacement, or the presence or absence of an internal standard. In this case, a peak position variability of ±0.2 2θ° was assumed to account for these potential variations without hindering the unambiguous identification of the indicated crystal form. The crystal form can be confirmed based on any unique combination of distinguishing peaks.

[1270] XRPD of Y-Aib-Q-G Form A

[1271] The prepared sample of Y-Aib-Q-G Form A was characterized by XRPD patterns using CuKα radiation as having the diffraction peaks (2-θ values) described in Table 20 below, and particularly having a peak at 6.3-6.4° 2-θ and one or more peaks selected from 4.5, 7.1, 13.0-13.1, 15.9-16.0, and 18.4-18.6° 2-θ; the tolerance of the diffraction angle is 0.2 degrees. A representative XRPD pattern of Y-Aib-Q-G Form A is shown in Figure 7A .

[1272] Table 20. X-ray Powder Diffraction Peaks of Y-Aib-Q-G Form A

[1273]

[1274]

[1275] XRPD of Y-Aib-Q-G Form B

[1276] The prepared sample of Y-Aib-Q-G Form B was characterized by XRPD patterns using CuKα radiation as having the diffraction peaks (2-θ values) described in Table 21 below, and particularly having a peak at 2-θ of 7.0 - 7.2° and one or more peaks selected from 2-θ of 5.0 - 5.4, 7.6 - 7.7, 8.8 - 8.9, 9.4 - 9.5, and 12.5 - 12.7°; the tolerance of the diffraction angle was 0.2 degrees. A representative XRPD pattern of Y-Aib-Q-G Form B is shown in Figure 7B .

[1277] Table 21. X-ray powder diffraction peaks of Y-Aib-Q-G Form B

[1278]

[1279] Example 7: (Boc)-His(dnp)-Aib-Gln(trt)-Gly

[1280]

[1281] Three crystalline solid forms of H(DNP)-Aib-Q-G tetramer were identified, including H(DNP)-Aib-Q-G Form A, Form B, and Form C.

[1282] H(DNP)-Aib-Q-G Form A is a crystalline and unstable solvate and readily converts to H(DNP)-Aib-Q-G Form C (during isolation or after drying).

[1283] H(DNP)-Aib-Q-G Form B is a crystalline material produced from a variety of solvent conditions. It represents a class of isostructural solvates.

[1284] H(DNP)-Aib-Q-G Form C is a semi-disordered crystalline material observed from a variety of solvent conditions.

[1285] H(DNP)-Aib-Q-G Form A

[1286] H(DNP)-Aib-Q-G Form A was prepared from acetonitrile (ACN) / methyl tert-butyl ether (MTBE). Approximately 50 mg of amorphous H(DNP)-Aib-Q-G tetramer was dissolved in 0.2 mL of 1:5 (v / v) ACN / MTBE at ambient conditions to form a clear yellow solution. With stirring, 0.1 mL of MTBE was added to the solution to produce a pale yellow slurry. The sample was stirred at ambient conditions for 5 days, and the wet solid was consistent with H(DNP)-Aib-Q-G Form A.

[1287] H(DNP)-Aib-Q-G Form B

[1288] Approximately 50 mg of amorphous H(DNP)-Aib-Q-G tetramer was dissolved in 0.2 mL of methyl acetate (MeOAc) under ambient conditions to form a clear yellow solution. Five 0.2 mL portions of cyclopentyl methyl ether (CPME) were added to the sample. The solution was stirred overnight under ambient conditions and then placed in a 2 - 8 °C refrigerator for approximately 6 weeks. A white solid was produced from the solution and was consistent with H(DNP)-Aib-Q-G Form B.

[1289] Following a similar procedure, H(DNP)-Aib-Q-G Form B was also produced at 2 - 8 °C from a 1:10 (volume / volume) nitromethane / MTBE solution.

[1290] Approximately 50 mg of amorphous H(DNP)-Aib-Q-G tetramer was dissolved in 0.2 mL of ethyl acetate (EtOAc) under ambient conditions to form a clear yellow solution. With stirring, 0.2 mL of heptane was added to the solution to produce a yellow viscous material. The sample was stirred at 36 °C for 7 days to produce a pale yellow slurry. The resulting solid was consistent with H(DNP)-Aib-Q-G Form B.

[1291] H(DNP)-Aib-Q-G Form C

[1292] H(DNP)-Aib-Q-G Form C was prepared from tetrahydrofuran (THF) / MTBE. Approximately 50 mg of amorphous H(DNP)-Aib-Q-G tetramer was dissolved in 0.1 mL of THF under ambient conditions to form a clear yellow solution. With stirring, five 0.1 mL portions of MTBE were added and the sample was stirred overnight under ambient conditions and then at 36 °C for 7 days to produce a pale yellow slurry. The sample was separated by centrifugation using a centrifuge tube filter under ambient conditions. The resulting solid was consistent with H(DNP)-Aib-Q-G Form C.

[1293] Following a similar procedure, H(DNP)-Aib-Q-G Form C can be produced from different MTBE-containing solvent systems such as EtOAc / MTBE, methyl ethyl ketone (MEK) / MTBE, etc.

[1294] The XRPD pattern of crystalline H(DNP)-Aib-Q-G tetramer was obtained on a Bruker D8 Endeavor X-ray powder diffractometer equipped with CuKα A source and a Linxeye detector were used, operating at 40 kV and 40 mA. The sample was scanned between 4 and 42 2θ°, with a step size of 0.009 2θ°, a scan rate of 0.5 seconds / step, and using a 0.3° primary slit opening and a 3.9° PSD opening. For Form A, the sample was scanned between 4 and 25 2θ° at a scan rate of 0.1 seconds / step. The powder was packed on a quartz or silicon sample holder, and a glass slide was used to obtain a smooth surface. The diffraction patterns of the crystal forms were collected at ambient temperature and relative humidity. The crystal peak positions were determined in MDI-Jade v7.9.9. In the field of crystallography, it is well known that for any given crystal form, the relative intensities of the diffraction peaks may vary due to preferred orientation caused by factors such as crystal morphology and habit. In the presence of a preferred orientation effect, the peak intensities are altered, but the characteristic peak positions of the polymorphs remain unchanged. See, for example, The United States Pharmacopeia #23, The National Formulary #18, pages 1843 - 1844, 1995. Additionally, in the field of crystallography, it is also well known that for any given crystal form, the angular peak positions may vary slightly. For example, the peak positions may shift due to changes in temperature during analysis of the sample, sample displacement, or the presence or absence of an internal standard. In this case, a peak position variability of ±0.2 2θ° was assumed to account for these potential variations without preventing the clear identification of the indicated crystal form. The crystal form can be confirmed based on any unique combination of distinguishable peaks.

[1295] XRPD of H(DNP)-Aib-Q-G Form A

[1296] The prepared sample of H(DNP)-Aib-Q-G Form A was characterized by XRPD patterns using CuKα radiation as having the diffraction peaks (2-θ values) described in Table 22 below, and particularly having a peak at 4.8° 2-θ and one or more peaks selected from 5.6, 6.2, 14.8, and 15.6° 2-θ; the tolerance of the diffraction angle was 0.2 degrees. A representative XRPD pattern of H(dnp)-Aib-Q-G Form A is shown in Figure 8A in.

[1297] Table 22. X-ray powder diffraction peaks of H(DNP)-Aib-Q-G Form A

[1298]

[1299]

[1300] XRPD of H(DNP)-Aib-Q-G Form B

[1301] The prepared sample of H(DNP)-Aib-Q-G Form B was characterized by XRPD patterns using CuKα radiation as having diffraction peaks (2-θ values) described in Table 23 below, and particularly having a peak at 5.3° 2-θ and one or more peaks selected from 7.7, 10.5, 11.3, 11.6, and 14.4° 2-θ; the tolerance for the diffraction angle was 0.2 degrees. A representative XRPD pattern of H(dnp)-Aib-Q-G Form B is shown in Figure 8B in.

[1302] Table 23. X-Ray Powder Diffraction Peaks of H(DNP)-Aib-Q-G Form B

[1303]

[1304]

[1305] XRPD of H(DNP)-Aib-Q-G Form C

[1306] The prepared sample of H(DNP)-Aib-Q-G Form C was characterized by XRPD patterns using CuKα radiation as having diffraction peaks (2-θ values) at 6.2 and 6.9° 2-θ, and the tolerance for the diffraction angle was 0.2 degrees. A representative XRPD pattern of H(dnp)-Aib-Q-G Form C is shown in Figure 8C in.

[1307] Example 8: (Boc)His(trt)-Aib-Gln(trt)-Gly

[1308]

[1309] Two crystalline solid forms of H(trt)-Aib-Q-G tetramer were identified, including H(trt)-Aib-Q-G Form A and Form B.

[1310] H(trt)-Aib-Q-G Form A is a crystalline material produced from various organic mixtures. It represents a class of isostructural solvates with variable solvent content in the unit cell.

[1311] H(trt)-Aib-Q-G Form B is a crystalline material produced from EtOH / H2O. It is a solvated form.

[1312] H(trt)-Aib-Q-G Form A

[1313] Preparation of H(trt)-Aib-Q-G Form A from tetrahydrofuran (THF) / methyl tert-butyl ether (MTBE). 50.3 mg of amorphous H(trt)-Aib-Q-G tetramer was stirred in 0.2 mL of 1:3 (v / v) THF / MTBE for 5 days under ambient conditions to yield a thick white slurry; 0.2 mL of 1:3 (v / v) THF / MTBE was added and the sample was stirred for an additional 3 days under ambient conditions and then isolated. The white solid (wet or isolated) obtained from the slurry was consistent with H(trt)-Aib-Q-G Form A.

[1314] Following a similar procedure, H(trt)-Aib-Q-G Form A can also be prepared from other organic solvent mixtures such as THF / heptane and 1,4-dioxane / H2O, acetonitrile (ACN) / MTBE, and ethyl acetate / MTBE, etc.

[1315] H(trt)-Aib-Q-G Form B

[1316] 50.3 mg of amorphous H(trt)-Aib-Q-G tetramer was stirred in 0.2 mL of 1:1 (v / v) ethanol / H2O under ambient conditions and after 5 days a mixture of white granules and pale yellow gel was produced. A 50 μL aliquot obtained from this slurry was added as a seed to a sample containing 311.2 mg of amorphous H(trt)-Aib-Q-G tetramer in 1 mL of 1:1 (v / v) ethanol / H2O. The sample was stirred for 5 days under ambient conditions. The undried solid isolated from the sample was consistent with H(trt)-Aib-Q-G Form B.

[1317] The XRPD pattern of crystalline H(trt)-Aib-Q-G tetramer was obtained on a Bruker D8 Endeavor X-ray powder diffractometer equipped with CuKα The source and Linxeye detector were operated at 40 kV and 40 mA. The sample was scanned between 4 and 42 2θ°, with a step size of 0.009 2θ°, and a scan rate of 0.5 seconds / step, and a 0.3° primary slit opening and 3.9° PSD opening were used. In some cases, the sample was scanned between 4 and 30 2θ° at a scan rate of 0.25 seconds / step. The powder was packed in a quartz or silicon sample holder, and a glass slide was used to obtain a smooth surface. The diffraction pattern of the crystal form was collected at ambient temperature and relative humidity. The crystal peak positions were determined in MDI-Jade v7.9.9. In the field of crystallography, it is well known that for any given crystal form, the relative intensities of the diffraction peaks may vary due to preferred orientation caused by factors such as crystal morphology and habit. In the presence of a preferred orientation effect, the peak intensities are altered, but the characteristic peak positions of the polymorphs do not change. See, for example, The United States Pharmacopeia #23, The National Formulary #18, pages 1843-1844, 1995. Additionally, in the field of crystallography, it is also well known that for any given crystal form, the angular peak positions may vary slightly. For example, the peak positions may shift due to changes in temperature during analysis of the sample, sample displacement, or the presence or absence of an internal standard. In this case, a peak position variability of ±0.2 2θ° was assumed to account for these potential variations without preventing the unambiguous identification of the indicated crystal form. The crystal form can be confirmed based on any unique combination of distinguishing peaks.

[1318] XRPD of H(trt)-Aib-Q-G Form A

[1319] The prepared sample of H(trt)-Aib-Q-G Form A was characterized by XRPD pattern using CuKα radiation as having the diffraction peaks (2-θ values) described in Table 24 below, and particularly having a peak at 4.7° 2-θ and one or more peaks selected from 5.5, 8.2, 10.1, 11.8, 13.3, 13.6, and 18.9° 2-θ; the tolerance of the diffraction angle was 0.2 degrees. A representative XRPD pattern of H(trt)-Aib-Q-G Form A is shown in Figure 9A in.

[1320] Table 24. X-ray Powder Diffraction Peaks of H(trt)-Aib-Q-G Form A

[1321]

[1322] XRPD of H(trt)-Aib-Q-G Form B

[1323] The prepared sample of H(trt)-Aib-Q-G Form B was characterized by XRPD patterns using CuKα radiation as having the diffraction peaks (2-θ values) described in Table 25 below, and specifically having a peak at 5.8° 2-θ and one or more peaks selected from 5.3, 8.9, 9.2, 15.2, 18.6 and 19.5° 2-θ; the tolerance for the diffraction angle was 0.2 degrees. A representative XRPD pattern of H(trt)-Aib-Q-G Form B is shown in Figure 9B as follows.

[1324] Table 25. X-ray powder diffraction peaks of H(trt)-Aib-Q-G Form B

[1325]

[1326] Example 9: (Fmoc)Asp(t-Bu)-Tyr(t-Bu)-Ser(t-Bu)-Lys

[1327]

[1328] Three crystalline solid forms of the OXM D-Y-S-K tetramer were identified, including D-Y-S-K Forms A, B and C.

[1329] D-Y-S-K Form A is a crystalline material produced from a variety of organic mixtures. It is a solvated form in the presence of wet conditions.

[1330] D-Y-S-K Form B is an anhydrous / unsolvated crystalline material.

[1331] D-Y-S-K Form C is a semi-disordered crystalline material and is produced from an MTBE / ETBE mixture. It is a solvated material.

[1332] D-Y-S-K Form A

[1333] D-Y-S-K Form A was prepared from methyl acetate (MeOAc) / dibutyl ether. 0.2 mL of MeOAc was added to 40.8 mg of amorphous D-Y-S-K tetramer to produce a clear solution; 3 x 0.2 mL of dibutyl ether was added to the solution and the slurry was left overnight under ambient conditions to form a white gel. The gel was broken into a viscous liquid and stirred for 1 day under ambient conditions and then stirred at about 36 °C for 5 days to produce a thick white slurry. The wet solid from the slurry was consistent with D-Y-S-K Form A.

[1334] Following a similar procedure, D-Y-S-K Form A can also be prepared from other organic solvent mixtures (such as acetone / dibutyl ether, acetonitrile (ACN) / dibutyl ether, ethyl acetate (EtOAc) / dibutyl ether, MeOAc / heptane and methyl ethyl ketone (MEK) / dibutyl ether, etc.).

[1335] D - Y - S - K Form B

[1336] D - Y - S - K Form B was prepared from methyl acetate (MeOAc) / ethyl tert - butyl ether (ETBE). 0.2 mL of MeOAc was added to 40.8 mg of amorphous D - Y - S - K tetramer to produce a clear solution; 3×0.2 mL of ETBE was added to the solution, and then the mixture was stirred for a total of 7 days under ambient conditions. A white gel was observed during stirring, which slowly transformed into a thick white slurry. The solid (wet or separated) from the slurry was consistent with D - Y - S - K Form B.

[1337] Following a similar procedure, D - Y - S - K Form B can also be prepared from other organic solvent mixtures such as ethyl acetate (EtOAc) / ETBE, methyl ethyl ketone (MEK) / ETBE, MEK / heptane, and amyl acetate / ETBE, etc.

[1338] D - Y - S - K Form B was also observed from the slurry of D - Y - S - K Form A when the solid was separated using a centrifuge tube filter and then air - dried for 4 hours or longer under ambient conditions.

[1339] D - Y - S - K Form C

[1340] 40.4 mg of amorphous D - Y - S - K solid was dissolved in 0.2 mL of MTBE by briefly heating the mixture at 62 °C. 3×0.2 mL of ETBE was added to the clear solution under ambient conditions, and a white gel formed after the slurry was left overnight under ambient conditions. The gel was broken into a viscous liquid and stirred for an additional 6 days under ambient conditions to produce a thick white slurry. The wet solid from the slurry was consistent with D - Y - S - K Form C.

[1341] The XRPD pattern of the crystalline T - F - T - S tetramer was obtained on a Bruker D8 Endeavor X - ray powder diffractometer equipped with CuKα A source and a Linxeye detector were used, operating at 40 kV and 40 mA. The sample was scanned between 4 and 42 2θ°, with a step size of 0.009 2θ°, a scan rate of 0.5 seconds per step, and using a 0.3° primary slit opening and a 3.9° PSD opening. For Forms A and C, the sample was scanned between 4 and 25 2θ°, with a scan rate of 0.1 seconds per step. The powder was packed on a quartz or silicon sample holder, and a glass slide was used to obtain a smooth surface. The diffraction patterns of the crystal forms were collected at ambient temperature and relative humidity. The crystal peak positions were determined in MDI-Jade v7.9.9. In the field of crystallography, it is well known that for any given crystal form, the relative intensities of the diffraction peaks may vary due to preferred orientation caused by factors such as crystal morphology and habit. In the presence of a preferred orientation effect, the peak intensities are altered, but the characteristic peak positions of the polymorphs do not change. See, for example, The United States Pharmacopeia #23, The National Formulary #18, pages 1843 - 1844, 1995. Additionally, in the field of crystallography, it is also well known that for any given crystal form, the angular peak positions may vary slightly. For example, the peak positions may shift due to changes in temperature during analysis of the sample, sample displacement, or the presence or absence of an internal standard. In this case, a peak position variability of ±0.2 2θ° was assumed to account for these potential variations without hindering the unambiguous identification of the indicated crystal forms. The crystal forms can be confirmed based on any unique combination of distinguishable peaks.

[1342] XRPD of D - Y - S - K Form A

[1343] The prepared sample of D - Y - S - K Form A was characterized by XRPD patterns using CuKα radiation as having the diffraction peaks (2 - θ values) described in Table 26 below, and particularly having a peak at 5.3° 2 - θ and one or more peaks selected from 6.0, 6.9, 7.2, 8.0, 12.2, and 15.6° 2 - θ; the tolerance of the diffraction angle was 0.2 degrees. A representative XRPD pattern of D - Y - S - K Form A is shown in Figure 10A in.

[1344] Table 26. X - ray powder diffraction peaks of D - Y - S - K Form A

[1345]

[1346]

[1347] XRPD of D - Y - S - K Form B

[1348] The prepared sample of D-Y-S-K Form B was characterized by XRPD patterns using CuKα radiation as having diffraction peaks (2-θ values) described in Table 27 below, and particularly having a peak at 5.8° 2-θ and one or more peaks selected from 4.4, 6.6, 10.1, 11.4, 13.4, and 15.5° 2-θ; the tolerance of the diffraction angle was 0.2 degrees. A representative XRPD pattern of D-Y-S-K Form B is shown in Figure 10B as follows.

[1349] Table 27. X-ray powder diffraction peaks of D-Y-S-K Form B

[1350]

[1351]

[1352] XRPD of D-Y-S-K Form C

[1353] The prepared sample of D-Y-S-K Form C was characterized by XRPD patterns using CuKα radiation as having diffraction peaks (2-θ values) described in Table 28 below, and particularly having peaks at 4.5 and 5.5° 2-θ and one or more peaks selected from 6.0 and 7.3° 2-θ; the tolerance of the diffraction angle was 0.2 degrees. A representative XRPD pattern of D-Y-S-K Form C is shown in Figure 10C as follows.

[1354] Table 28. X-ray powder diffraction peaks of D-Y-S-K Form C

[1355]

[1356] Example 10: (Fmoc)Tyr-Ser(t-Bu)-Lys(Boc)-Tyr(t-Bu)

[1357]

[1358] Multiple crystalline solid forms of the OXM Y-S-K-Y tetramer were identified, including Y-S-K-Y Forms A to E. A polymorph diagram describing their relationships is shown in Figure 11 as follows. It is a desolvated solvate generated from the solvated forms from EtOH (Form B) or IPA (Form C). Form A converts to Form D upon heating to 150 °C; Form D was also observed from MEK.

[1359] Y-S-K-Y Form A

[1360] Dissolve 50.3 mg of the Y-S-K-Y amorphous solid in 0.8 mL of EtOH at 50 °C. Then remove the solution from the 50 °C hot plate and place it in the refrigerator. The solid was observed the next day, separated, and air-dried under ambient conditions. The resulting white solid was consistent with Y-S-K-Y Form A.

[1361] Dissolve 50.4 mg of the Y-S-K-Y amorphous solid in 0.75 mL of IPA at 50 °C. Then remove the solution from the 50 °C hot plate and place it in the refrigerator. The solid was observed the next day, separated, and air-dried under ambient conditions. The resulting white solid was consistent with Y-S-K-Y Form A.

[1362] Y-S-K-Y Form B

[1363] Dissolve 297.0 mg of the Y-S-K-Y amorphous solid in 2.5 mL of EtOH at 54 °C to produce a slightly turbid solution. With stirring, allow the solution to cool slowly to ambient temperature on a hot plate and turn off the heater. A white suspension was obtained, and the solid was consistent with Y-S-K-Y Form B when analyzed in the wet state.

[1364] Y-S-K-Y Form C

[1365] Stir 50.4 mg of the Y-S-K-Y amorphous solid in 1 mL of IPA overnight under ambient conditions to produce a clear solution. Allow the solution to evaporate from a de-capped vial (covered with perforated Al foil) under ambient conditions. The resulting moist solid was consistent with Y-S-K-Y Form C.

[1366] Dissolve 223.6 mg of the Y-S-K-Y amorphous solid in 1 mL of IPA at 54 °C to form a slightly turbid solution. With stirring, allow the solution to cool slowly to ambient temperature on a hot plate and turn off the heater. A white solid was obtained in the solution and was consistent with Y-S-K-Y Form C when analyzed in the wet state.

[1367] Y-S-K-Y Form D

[1368] Heat 11.1 mg of the Y-S-K-Y Form A solid on a TGA to 150 °C and hold at that temperature for 5 minutes. Then remove the sample from the TGA instrument and analyze it by XRPD under ambient conditions. The resulting sample was a white solid and was consistent with Y-S-K-Y Form D.

[1369] At ambient temperature, 50.4 mg of the Y-S-K-Y amorphous solid was dissolved in 0.5 mL of dioxane to form a clear solution. With stirring, 2 × 0.25 mL of water was added to the solution to produce a gel. The sample was vortexed to break up the gel and the sample was stirred for 1 day under ambient conditions. An aliquot was taken from the white slurry into a clean silicon XRPD sample holder and air-dried overnight on the sample holder under ambient conditions. The resulting solid was consistent with Y-S-K-Y Form D.

[1370] The XRPD pattern of crystalline Y-S-K-Y tetramer was obtained on a Bruker D8 Endeavor X-ray powder diffractometer equipped with a CuKα source and a Linxeye detector, operating at 40 kV and 40 mA. The sample was scanned between 4 and 42 2θ°, with a step size of 0.009 2θ° and a scan rate of 0.5 seconds / step, and using a 0.3° primary slit opening and a 3.9° PSD opening. The sample was also scanned between 4 and 30 2θ° at a scan rate of 0.25 seconds / step, or between 4 and 25 2θ° at a scan rate of 0.1 seconds / step. The powder was packed onto a silicon sample holder, and a glass slide was used to obtain a smooth surface. Diffraction patterns of the crystal form were collected at ambient temperature and relative humidity. Crystal peak positions were determined in MDI-Jade v7.9.9. It is well known in the field of crystallography that for any given crystal form, the relative intensities of diffraction peaks may vary due to preferred orientation resulting from factors such as crystal morphology and habit. In the presence of a preferred orientation effect, the peak intensities are altered, but the characteristic peak positions of the polymorphs do not change. See, for example, The United States Pharmacopeia #23, National Formulary #18, pages 1843-1844, 1995. Additionally, it is well known in the field of crystallography that for any given crystal form, the angular peak positions may vary slightly. For example, the peak positions may shift due to changes in temperature during analysis of the sample, sample displacement, or the presence or absence of an internal standard. In the present case, a peak position variability of ±0.2 2θ° was assumed to account for these potential variations without precluding the unambiguous identification of the indicated crystal form. The crystal form can be confirmed based on any unique combination of distinguishing peaks.

[1371] XRPD of Y-S-K-Y Form A

[1372] The prepared sample of Y-S-K-Y Form A was characterized by XRPD patterns using CuKα radiation as having diffraction peaks (2-θ values) described in Table 29 below, and particularly having peaks at 18.1 and 18.7° 2-θ and one or more peaks selected from 5.7, 8.7, 13.7, 14.3, 15.9 and 16.2° 2-θ; the tolerance of the diffraction angle was 0.2 degrees. A representative XRPD pattern of Y-S-K-Y Form A is shown in Figure 12A .

[1373] Table 29. X-ray powder diffraction peaks of Y-S-K-Y Form A

[1374]

[1375] XRPD of Y-S-K-Y Form B

[1376] The prepared sample of Y-S-K-Y Form B was characterized by XRPD patterns using CuKα radiation as having diffraction peaks (2-θ values) described in Table 30 below, and particularly having peaks at 5.9 and 10.5° 2-θ and one or more peaks selected from 7.1, 8.9, 14.6 and 16.6° 2-θ; the tolerance of the diffraction angle was 0.2 degrees. A representative XRPD pattern of Y-S-K-Y Form B is shown in Figure 12B ..

[1377] Table 30. X-ray powder diffraction peaks of Y-S-K-Y Form B

[1378]

[1379] XRPD of Y-S-K-Y Form C

[1380] The prepared sample of Y-S-K-Y Form C was characterized by XRPD patterns using CuKα radiation as having diffraction peaks (2-θ values) described in Table 31 below, and particularly having peaks at 7.8 and 20.3° 2-θ and one or more peaks selected from 5.8, 15.5 and 19.5° 2-θ; the tolerance of the diffraction angle was 0.2 degrees. A representative XRPD pattern of Y-S-K-Y Form C is shown in Figure 12C ..

[1381] Table 31. X-ray powder diffraction peaks of Y-S-K-Y Form C

[1382]

[1383] XRPD of Y-S-K-Y Form D

[1384] The prepared sample of Y-S-K-Y form D was characterized by XRPD patterns using CuKα radiation as having the diffraction peaks (2-θ values) described in Table 32 below, and particularly having peaks at 5.9 and 7.4° 2-θ and one or more peaks selected from 6.5, 6.9, and 14.8° 2-θ; the tolerance of the diffraction angle was 0.2 degrees. A representative XRPD pattern of Y-S-K-Y form D is shown in Figure 12D as follows.

[1385] Table 32. X-ray powder diffraction peaks of Y-S-K-Y form D

[1386]

[1387] Example 11: Fmoc-G-P-S-S-G-NH2 pentamer

[1388]

[1389] Fmoc-G-P-S-S-G-NH2 crystalline form

[1390] Multiple crystalline solid forms of the OXM Fmoc-protected G-P-S-S-G-NH2 pentamer were identified, including Fmoc-G-P-S-S-G-NH2 forms A to E. A polymorph diagram describing their relationship is shown in Figure 13 as follows. Among them, form B is a variable solvate from acetone, while form A is a desolvated solvate from acetonitrile, and form D is a desolvated solvate from MEK.

[1391] Fmoc-G-P-S-S-G-NH2 forms A and C

[1392] Fmoc-G-P-S-S-G-NH2 form C was prepared from acetonitrile (ACN). 159.9 mg of amorphous Fmoc-G-P-S-S-G-NH2 solid was stirred in 0.5 mL of ACN under ambient conditions, resulting in gel formation. Another 0.5 mL of ACN was added to the sample to facilitate stirring, and a white slurry was observed the next day. Another 0.8 mL of ACN was added, and the sample was stirred under ambient conditions for a total of 3 weeks. The resulting white solid was consistent with Fmoc-G-P-S-S-G-NH2 form C when analyzed in the wet state.

[1393] The above white slurry was transferred to a 0.45 μm nylon centrifuge tube filter and centrifuged at ambient temperature for 5 minutes to separate the solid and liquid. The separated solid was dried overnight in a vacuum drying oven at ambient temperature. The resulting white solid was consistent with Fmoc-G-P-S-S-G-NH2 form A.

[1394] Fmoc-G-P-S-S-G-NH2 form B

[1395] Preparation of Fmoc-G-P-S-S-G-NH2 Form B from acetone. 150.1 mg of the solid of amorphous Fmoc-G-P-S-S-G-NH2 was stirred in 0.5 mL of acetone under ambient conditions to cause gel formation. Another 0.5 mL of acetone was added to the sample to facilitate stirring, and a white slurry was observed the next day. Another 0.3 mL of acetone was added, and the sample was stirred under ambient conditions for a total of 3 weeks. The resulting white solid (wet or dry) was Fmoc-G-P-S-S-G-NH2 Form B.

[1396] Fmoc-G-P-S-S-G-NH2 Forms D and E

[1397] Preparation of Fmoc-G-P-S-S-G-NH2 Form E from methyl ethyl ketone (MEK). 110.4 mg of the solid of amorphous Fmoc-G-P-S-S-G-NH2 was stirred in 0.5 mL of MEK under ambient conditions to cause gel formation. Another 2 × 0.5 mL of MEK was added to the sample to facilitate stirring, which produced a mixture of white solid and gel in the sample the next day. The sample was sonicated in a water bath and manually stirred with a spatula to break the gel, and a white slurry was obtained. The sample was stirred under ambient conditions for a total of 3 weeks. The resulting white solid was consistent with Fmoc-G-P-S-S-G-NH2 Form E when analyzed in the wet state.

[1398] The above white slurry was transferred to a 0.45 μm nylon centrifuge tube filter and centrifuged at ambient temperature for 5 minutes to separate the solid and the liquid. The separated solid was dried overnight in a vacuum drying oven at ambient temperature. The resulting white solid was consistent with Fmoc-G-P-S-S-G-NH2 Form D.

[1399] The XRPD pattern of the crystalline Fmoc-G-P-S-S-G-NH2 pentamer was obtained on a Bruker D8 Endeavor X-ray powder diffractometer equipped with CuKα The source and the Linxeye detector were operated at 40 kV and 40 mA. The sample was scanned between 4 and 42 2θ°, with a step size of 0.009 2θ°, and a scan rate of 0.5 seconds / step, and a 0.3° primary slit opening and a 3.9° PSD opening were used. For Fmoc-G-P-S-S-G-NH2 Form C and Form E, the sample was scanned between 4 and 25 2θ°, with a scan rate of 0.1 seconds / step. The powder was packed on a quartz or silicon sample holder, and a glass slide was used to obtain a smooth surface. The diffraction patterns of the crystal forms were collected at ambient temperature and relative humidity. The crystal peak positions were determined in MDI-Jade v7.9.9. It is well known in the field of crystallography that for any given crystal form, the relative intensities of the diffraction peaks may vary due to preferred orientation caused by factors such as crystal morphology and habit. In the presence of preferred orientation effects, the peak intensities are altered, but the characteristic peak positions of the polymorphs do not change. See, for example, The United States Pharmacopeia #23, National Formulary #18, pages 1843 - 1844, 1995. Additionally, it is well known in the field of crystallography that for any given crystal form, the angular peak positions may vary slightly. For example, the peak positions may shift due to changes in temperature during analysis of the sample, sample displacement, or the presence or absence of an internal standard. In this case, a peak position variability of ±0.2 2θ° is assumed to account for these potential variations without hindering the unambiguous identification of the indicated crystal forms. The crystal forms can be confirmed based on any unique combination of distinguishing peaks.

[1400] XRPD of Fmoc-G-P-S-S-G-NH2 Form A

[1401] The prepared sample of Fmoc-G-P-S-S-G-NH2 Form A was characterized by XRPD patterns using CuKα radiation as having the diffraction peaks (2-θ values) described in Table 33 below, and particularly having peaks at 5.8 and 18.5° 2-θ and one or more peaks selected from 8.6, 9.4, 12.9, 13.8, 17.2, and 19.4° 2-θ; the tolerance for the diffraction angle is 0.2 degrees. A representative XRPD pattern of Fmoc-G-P-S-S-G-NH2 Form A is shown in Figure 14A in.

[1402] Table 33. X-ray powder diffraction peaks of Fmoc-G-P-S-S-G-NH2 Form A

[1403]

[1404]

[1405] XRPD of Fmoc-G-P-S-S-G-NH2 Form B

[1406] The prepared sample of Fmoc-G-P-S-S-G-NH2 Form B was characterized by XRPD patterns using CuKα radiation as having diffraction peaks (2-θ values) described in Table 34 below, and particularly having peaks at 7.0 - 7.1 and 7.5 - 7.7° 2-θ and one or more peaks selected from 5.3 - 5.4, 9.7 - 9.9, and 14.7 - 14.9° 2-θ; the tolerance for the diffraction angle was 0.2 degrees. A representative XRPD pattern of Fmoc-G-P-S-S-G-NH2 Form B is shown in Figure 14B the

[1407] Table 34. X-ray powder diffraction peaks of Fmoc-G-P-S-S-G-NH2 Form B

[1408]

[1409] XRPD of Fmoc-G-P-S-S-G-NH2 Form C

[1410] The prepared sample of Fmoc-G-P-S-S-G-NH2 Form C was characterized by XRPD patterns using CuKα radiation as having diffraction peaks (2-θ values) described in Table 35 below, and particularly having a peak at 8.3° 2-θ and one or more peaks selected from 6.3, 11.4, 14.3, and 16.6° 2-θ; the tolerance for the diffraction angle was 0.2 degrees. A representative XRPD pattern of Fmoc-G-P-S-S-G-NH2 Form C is shown in Figure 14C the

[1411] Table 35. X-ray powder diffraction peaks of Fmoc-G-P-S-S-G-NH2 Form C

[1412]

[1413] XRPD of Fmoc-G-P-S-S-G-NH2 Form D

[1414] The prepared sample of Fmoc-G-P-S-S-G-NH2 Form D was characterized by XRPD patterns using CuKα radiation as having diffraction peaks (2-θ values) described in Table 36 below, and particularly having a peak at 7.2° 2-θ and one or more peaks selected from 6.8, 8.6, 15.8, and 18.9° 2-θ; the tolerance for the diffraction angle was 0.2 degrees. A representative XRPD pattern of Fmoc-G-P-S-S-G-NH2 Form D is shown in Figure 14D the

[1415] Table 36. X-ray powder diffraction peaks of Fmoc-G-P-S-S-G-NH2 Form D

[1416]

[1417] XRPD of Fmoc-G-P-S-S-G-NH2 Form E

[1418] The prepared sample of Fmoc-G-P-S-S-G-NH2 Form E was characterized by XRPD patterns using CuKα radiation as having the diffraction peaks (2-θ values) described in Table 37 below, and specifically having a peak at 6.1° 2-θ and one or more peaks selected from 6.3, 7.8, 10.0 and 12.4° 2-θ; the tolerance of the diffraction angle was 0.2 degrees. A representative XRPD pattern of Fmoc-G-P-S-S-G-NH2 Form E is shown in Figure 14E in.

[1419] Table 37. X-ray powder diffraction peaks of Fmoc-G-P-S-S-G-NH2 Form E

[1420]

[1421] Example 12: Fmoc-Gly-Pro-Ser(tBu)-Ser(tBu)-Gly-OH

[1422]

[1423] Crystallization screening of Fmoc-G-P-S-S-G-OH free form was performed using various solvents and solvent mixtures. Different crystallization methods were employed, including solvent-based techniques such as slurry, cooling, ambient temperature and sub-ambient temperature holding, solvent / anti-solvent addition or combinations of techniques, and non-solvent-based techniques such as thermal stress.

[1424] Two solid forms were identified: Fmoc-G-P-S-S-G-OH Form A and Fmoc-G-P-S-S-G-OH Form B. Form A is a solvated form generated from 1-propanol (1-PrOH) or a mixture containing 1-PrOH such as 1-PrOH / heptane. Form B is the desolvated product of Form A.

[1425] Fmoc-G-P-S-S-G-OH Form A

[1426] Preparation 1:

[1427] Preparation of Fmoc-G-P-S-S-G-OH Form A in 1-propanol (1-PrOH). 16 mL of 1-PrOH was added to 4.06 grams of the amorphous solid of Fmoc-G-P-S-S-G-OH and the sample was stirred under ambient conditions, which produced an orange-red solution. The solution was inoculated with 2.8 mg of Fmoc-G-P-S-S-G-OH Form A and then stirring was continued for 2 days under ambient conditions. A light orange suspension was obtained and the solid was separated by vacuum filtration using a 10 μm disposable filter, rinsed twice on the filter with 0.5 mL of fresh 1-PrOH, and then collected and dried under vacuum at 30 °C for approximately 3 - 4 hours. The resulting white solid (3.2 grams) was consistent with Fmoc-G-P-S-S-G-OH Form A.

[1428] Preparation 2:

[1429] Preparation of Fmoc-G-P-S-S-G-OH Form A in 1-propanol (1-PrOH) and heptane. Approximately 50 mg of amorphous Fmoc-G-P-S-S-G-OH was dissolved in 0.6 mL of 1-PrOH to form a clear yellow solution. The solution in 30 μL aliquots was added to 0.6 mL of heptane to produce a clear light yellow solution. With stirring, an additional 0.6 mL of heptane was added to the solution and the sample was capped and stirred for 2 days under ambient conditions. A suspension was obtained and the solid was consistent with Fmoc-G-P-S-S-G-OH Form A.

[1430] Preparation 3:

[1431] Preparation of Fmoc-G-P-S-S-G-OH Form A in 1-propanol (1-PrOH). Approximately 10 mg of amorphous Fmoc-G-P-S-S-G-OH was dissolved in 0.1 mL of 1-PrOH to form a clear yellow solution. The solution was stored in a capped vial under ambient conditions for 1 day and then transferred to the refrigerator for 3 days. The solid observed in the solution was consistent with Fmoc-G-P-S-S-G-OH Form A.

[1432] Fmoc-G-P-S-S-G-OH Form B

[1433] The solid of Fmoc-G-P-S-S-G-OH Form A was loaded onto a clean TGA pan, heated to 120 °C in a TGA furnace and held at that temperature for 3 minutes. The resulting white solid was consistent with Fmoc-G-P-S-S-G-OH Form B.

[1434] XRPD of Fmoc-G-P-S-S-G-OH Form A

[1435] The XRPD pattern of crystalline Fmoc-G-P-S-S-G-OH Form A was obtained on a Bruker D8 Endeavor X-ray powder diffractometer equipped with a CuKα source and a Linxeye detector, operating at 40 kV and 40 mA. The sample was scanned between 4 and 42 2θ°, with a step size of 0.009 2θ° and a scan rate of 0.5 s / step, and using a 0.3° primary slit opening and a 3.9° PSD opening. The powder was filled into a quartz sample holder, and a glass slide was used to obtain a smooth surface. The diffraction pattern was collected at ambient temperature and relative humidity. The crystal peak positions were determined in MDI-Jade v7.9.9.

[1436] The prepared sample of Fmoc-G-P-S-S-G-OH Form A was characterized by XRPD pattern using CuKα radiation as having diffraction peaks (2-θ values) described in Table 38 below, and particularly having a peak at 6.1° 2-θ and one or more peaks selected from 8.5, 11.7, 12.3, and 16.9° 2-θ; the tolerance of the diffraction angle was 0.2 degrees. A representative XRPD pattern of Y-Aib-Q-G Form A is shown in Figure 15A in.

[1437] Table 38. X-ray powder diffraction peaks of Fmoc-G-P-S-S-G-OH Form A

[1438]

[1439] XRPB of Fmoc-G-P-S-S-G-OH Form B

[1440] Using the same procedure as for Fmoc-G-P-S-S-G-OH Form A, but scanning the Fmoc-GPSSG-OH Form B sample between 4 and 30 2θ° at a scan rate of 0.25 s / step, the XRPD pattern of crystalline Fmoc-G-P-S-S-G-OH Form B was obtained.

[1441] The prepared sample of Fmoc-G-P-S-S-G-OH Form B was characterized by XRPD pattern using CuKα radiation as having diffraction peaks (2-θ values) described in Table 39 below, and particularly having a peak at 7.2° 2-θ and one or more peaks selected from 5.3, 8.1, 14.4, and 16.2° 2-θ; the tolerance of the diffraction angle was 0.2 degrees. A representative XRPD pattern of Fmoc-G-P-S-S-G-OH Form B is shown in Figure 15B in.

[1442] Table 39. X-ray powder diffraction peaks of Fmoc-G-P-S-S-G-OH Form B

[1443]

[1444] Example 13: GGG side chain

[1445]

[1446] Preparation method, crystallization and use

[1447] Charge 2-(2-(2-aminoethoxy)ethoxy)acetic acid (1.16 equivalents) and 5 volumes of acetonitrile into a jacketed reactor. Slowly add N-methyl-N-trimethylsilylacetamide (2.56 equivalents) thereto. Stir it at 20 - 25 °C for about 2 - 3 hours. The reaction mixture is clear, and 1 equivalent of (O1-tert-butyl O5-(2,5-dioxopyrrolidin-1-yl) (2S)-2-[(20-tert-butoxy-20-oxo-eicosanoyl)amino]pentanedioate) is added to the reaction mixture. Stir the reaction mixture at about 20 - 25 °C for 4 - 5 hours. Add about 9 volumes of 2-methyltetrahydrofuran (2-Me-THF) to the reaction mixture, followed by extraction with 3 x 4 volumes of 2% aqueous KHSO4 and 1% NaCl solution. Then wash the organic solution with 4 x 4 volumes of 2% aqueous NaCl solution. Concentrate the organic solution under vacuum to reduce acetonitrile (<0.1%) and water (KF <0.5%). Add 1 volume of DMF to prepare a DMF solution of (2-[2-[2-[[(4S)-5-tert-butoxy-4-[(20-tert-butoxy-20-oxo-eicosanoyl)amino]-5-oxo-valeryl]amino]ethoxy]ethoxy]acetic acid). Concentrate the organic mixture under vacuum to reduce 2-Me-THF to less than 5%. Prepare a DMF feed solution of (2-[2-[2-[[(4S)-5-tert-butoxy-4-[(20-tert-butoxy-20-oxo-eicosanoyl)amino]-5-oxo-valeryl]amino]ethoxy]ethoxy]acetic acid) containing 2.4 equivalents of DIEA; a DMF solution of TNTU and a DMF solution of (((9H-fluoren-9-yl)methoxy)carbonyl)-L-lysine hydrochloride. Also prepare feed tanks for 2-MeTHF and 3% aqueous KHSO4 and 5% NaCl. Adjust the flow rates of the (2-[2-[2-[[(4S)-5-tert-butoxy-4-[(20-tert-butoxy-20-oxo-eicosanoyl)amino]-5-oxo-valeryl]amino]ethoxy]ethoxy]acetic acid (containing 2.4 equivalents of DIEA) solution and the TNTU solution to add 0.97 equivalents of TNTU relative to (2-[2-[2-[[(4S)-5-tert-butoxy-4-[(20-tert-butoxy-20-oxo-eicosanoyl)amino]-5-oxo-valeryl]amino]ethoxy]ethoxy]acetic acid). Warm the reaction mixture in the reactor coil at about 30 °C and then introduce it into the DMF solution stream of (((9H-fluoren-9-yl)methoxy)carbonyl)-L-lysine hydrochloride to react with 1.15 equivalents of (((9H-fluoren-9-yl)methoxy)carbonyl)-L-lysine hydrochloride in the reactor coil at about 30 °C to produce the GGG side chain product. Then, dilute the reaction solution with 30 volumes of 2-MeTHF and quench it with 20 volumes of 3% aqueous KHSO4 and 5% NaCl solution.Then cool the organic solution to 10 - 20 °C and separate the aqueous phase. Concentrate the organic solution to 11 - 13 volumes, add 2.3 - 2.7 volumes of DMF, and then extract with 5 volumes of 3% aqueous KHSO4 and 5% NaCl solution. Dilute the organic phase with 2.3 - 2.7 volumes of DMF and extract with 5 volumes of 3% aqueous KHSO4 and 5% NaCl solution. Then, add 2.5 - 3.2 volumes of 2-MeTHF and 2.3 - 2.7 volumes of DMF, and extract the organic phase with 5 volumes of 3% aqueous KHSO4 and 5% NaCl solution. Repeat the cycle of diluting with DMF, extracting with 3% KHSO4 and 5% NaCl solution, then diluting with 2-MeTHF and DMF, and subsequently extracting with 3% KHSO4 and 5% NaCl solution one more time. Then add 2.5 - 3.2 volumes of 2-MeTHF, and extract the organic solution with 5% aqueous NaCl solution 4 times. Then concentrate the 2-MeTHF solution, and exchange 2-MeTHF with acetonitrile by repeatedly adding acetonitrile and concentrating the solution under vacuum to reduce 2-MeTHF to below 10%.

[1448] Crystallization

[1449] After solvent exchange by distillation, add ACN to 30 volumes. Heat the solution to 55 °C to completely dissolve all side chain materials. Cool the solution to 5 °C over 4 hours, and then hold for 4 hours for primary nucleation. Primary nucleation occurs reliably during the holding at 5 °C, and a mixture of amorphous and crystalline materials is produced. This is not desired, so the next step is designed to convert to crystalline material.

[1450] Warm the solution to 30 °C and hold for 8 hours to dissolve the amorphous material. Next, add 6 volumes of MEK, and hold the solution for an additional 3 hours to dissolve additional amorphous material, and then cool to 20 °C. Convert the amorphous material to crystalline material using four heat cycles: in each cycle, heat the mixture to 30 °C, hold for 3 hours, then cool to 20 °C and hold for 3 hours.

[1451] After the heat cycles, cool the mixture to 5 °C over 1 hour and hold for 1 hour. Collect the supernatant sample and examine the side chain efficacy by HPLC. If the side chain concentration is 5 mg / mL or lower, it indicates that the solid form is a low solubility crystalline form. Then filter the slurry, wash three times with 10 volumes of ACN at 5 °C and dry at 30 °C.

[1452] GGG side chain crystalline form

[1453] Three crystalline solid forms of the GGG side chain were identified, including GGG SC form A, form B, and form C.

[1454] Form A is a crystalline anhydrous / unsolvated form and has been observed at ambient temperature from various solvent conditions.

[1455] Form B is a crystalline material and has been observed in water.

[1456] Form C is a crystalline anhydrous / unsolvated form and has been observed at elevated temperature.

[1457] GGG SC Form A

[1458] 241.2 mg of the solid of the GGG side chain was added to 2 mL of 1:3 volume / volume MEK / ACN, and the mixture was heated at about 75 °C for 10 minutes to produce a clear solution. The solution remained clear after being slowly cooled to ambient temperature.

[1459] Approximately half of the volume of the above solution was seeded with the disordered Form A and then stirred under ambient conditions, which first produced gel particles and then a thick white paste with no flowable liquid. After adding an additional 0.5 mL of 1:3 volume / volume MEK / ACN, the sample was stirred for 2 days under ambient conditions to produce a thick white slurry. The white solid separated from the sample by vacuum filtration was consistent with GGG side chain Form A.

[1460] GGG side chain Form A was also obtained by stirring the above solution under ambient conditions without seeding. The sample also formed gel particles and a thick white paste, which required the addition of an additional volume of 1:3 volume / volume MEK / ACN to become a slurry.

[1461] GGG side chain Form B

[1462] Approximately 20 mg of the disordered GGG side chain solid was slurried in water at 60 °C to produce birefringent white particles. The sample was separated and dried on a Whatman filter under a nitrogen stream. And the resulting white solid was consistent with GGG side chain Form B.

[1463] GGG side chain Form C

[1464] GGG side chain Form A was heated to 93 °C and the resulting solid was consistent with GGG side chain Form C.

[1465] XRPD patterns of the crystalline GGG side chain (Form A or Form B) were obtained on a Bruker D8 Endeavor X-ray powder diffractometer equipped with CuKα The source and Linxeye detector were operated at 40 kV and 40 mA. The sample was scanned between 4 and 42 2θ°, with a step size of 0.009 2θ° and a scan rate of 0.5 seconds per step, and a 0.3° primary slit opening and 3.9° PSD opening were used. In some cases, the scan range was 4 and 30 2θ°, with a step size of 0.009 2θ° and a scan rate of 0.25 seconds per step. The sample was loaded in a quartz or silicon sample holder, and a glass slide was used to obtain a smooth surface. Diffraction patterns of the crystal form were collected at ambient temperature and relative humidity. Crystal peak positions were determined in MDI-Jade v7.9.9. It is well known in the field of crystallography that for any given crystal form, the relative intensities of diffraction peaks can vary due to preferred orientation caused by factors such as crystal morphology and habit. In the presence of a preferred orientation effect, the peak intensities are altered, but the characteristic peak positions of the polymorphs do not change. See, for example, The United States Pharmacopeia #23, National Formulary #18, pages 1843 - 1844, 1995. Additionally, it is well known in the field of crystallography that for any given crystal form, the angular peak positions can vary slightly. For example, the peak positions can shift due to changes in temperature during analysis of the sample, sample displacement, or the presence or absence of an internal standard. In this case, a peak position variability of ±0.2 2θ° was assumed to account for these potential variations without preventing the unambiguous identification of the indicated crystal form. The crystal form can be confirmed based on any unique combination of distinguishing peaks.

[1466] Using a PANalytical X'Pert PRO MPD diffractometer, an incident beam of Cu Kα radiation generated by a long fine focus source and a nickel filter was used to obtain the XRPD pattern of crystalline GGG side chain form C. The diffractometer was configured using symmetric Bragg - Brentano geometry. Data was collected and analyzed using Data Collector software v.2.2b. Prior to analysis, a silicon sample (NIST SRM 640e) was analyzed to verify that the observed Si111 peak position was consistent with the NIST - certified position.

[1467] The sample of the sample was filled into a nickel-coated copper well. An anti-scattering slit (SS) was used to minimize the background generated by air scattering. Soller slits for the incident beam and the diffracted beam were used to minimize the broadening caused by axial divergence. A scanning position-sensitive detector (X'Celerator) located 240 mm from the sample was used to collect the diffraction pattern. The data collection range was 3.5° - 30° 2θ, with a step size of 0.017 2θ°. The crystal peak positions were determined in MDI-Jade v7.9.9. In the field of crystallography, it is well known that for any given crystal form, the relative intensities of the diffraction peaks may vary due to preferred orientation caused by factors such as crystal morphology and habit. In the presence of a preferred orientation effect, the peak intensities will change, but the characteristic peak positions of the polymorphs do not change. See, for example, The United States Pharmacopeia #23, National Formulary #18, pages 1843 - 1844, 1995. Additionally, in the field of crystallography, it is also well known that for any given crystal form, the angular peak positions may vary slightly. For example, the peak positions may shift due to changes in temperature during analysis of the sample, sample displacement, or the presence or absence of an internal standard. In this case, a peak position variability of ±0.2 2θ° was assumed to account for these potential variations without preventing the clear identification of the indicated crystal form. The crystal form can be confirmed based on any unique combination of distinguishing peaks.

[1468] XRPD of GGG side chain form A

[1469] The prepared sample of GGG side chain form A was characterized by XRPD patterns using CuKα radiation as having the diffraction peaks (2-θ values) described in Table 40 below, and particularly having a peak at 11.4° 2-θ and one or more peaks selected from 6.0, 8.9, 12.7, 13.6, 14.6, 17.0, and 18.8° 2-θ; the tolerance for the diffraction angle was 0.2 degrees. A representative XRPD pattern of GGG side chain form A is shown in Figure 16A .

[1470] Table 40. X-ray powder diffraction peaks of GGG side chain form A

[1471]

[1472]

[1473] XRPD of GGG side chain form B

[1474] The prepared sample of GGG side chain form B was characterized by XRPD patterns using CuKα radiation as having diffraction peaks (2-θ values) described in Table 41 below, and particularly having a peak at 10.6° 2-θ and one or more peaks selected from 7.1, 12.1, 13.6, 14.2, 15.2, 16.0 and 16.8° 2-θ; the tolerance of the diffraction angle was 0.2 degrees. The representative XRPD pattern of GGG side chain form B is shown in Figure 16B .

[1475] Table 41. X-ray powder diffraction peaks of GGG side chain form B

[1476]

[1477]

[1478] XRPD of GGG side chain form C

[1479] The prepared sample of GGG side chain form C was characterized by XRPD patterns using CuKα radiation as having diffraction peaks (2-θ values) described in Table 42 below, and particularly having peaks at 10.1 and 15.5° 2-θ and one or more peaks selected from 6.1, 8.7, 11.4, 16.6 and 19.2° 2-θ; the tolerance of the diffraction angle was 0.2 degrees. The representative XRPD pattern of GGG side chain form C is shown in Figure 16C .

[1480] Table 42. X-ray powder diffraction peaks of GGG side chain form C

[1481]

[1482]

[1483] Example 14: H-Ala-Pro-Pro-Pro-Ser(tBu)-NH2

[1484]

[1485] Crystallization studies were carried out on the free form (free base) and H-Ala-Pro-Pro-Pro-Ser(tBu)-NH2 (H-A-P-P-P-S-NH2) by salt / eutectic formation.

[1486] Attempts were made to crystallize the free form in various solvents and solvent mixtures. Different techniques were employed, such as slurry, cooling, and holding at ambient temperature and below ambient temperature. Crystalline H-A-P-P-P-S-NH2 was not identified under the conditions examined.

[1487] Crystallization also occurs through salt formation. A total of 96 conditions were examined at a ratio of approximately 1:1.2 moles / mole (peptide / acid), including 12 counterions, each in 8 different solvents. The counterions and solvents employed in the screening are listed in Table 43 below. Crystalline mono-HCl salts were observed in ACN (only under wet conditions) and acetone.

[1488] Table 43. Counterions and Solvents

[1489] Counterion Solvent Benzenesulfonic acid Water Citric acid ACN Ethane-1,2-disulfonic acid 95% ethanol Ethanesulfonic acid IPA Hydrochloric acid Acetone L-Malic acid 88% Acetone Methanesulfonic acid Ethyl acetate Phosphoric acid CPME Saccharin Sulfuric acid L-Tartaric acid p-Toluenesulfonic acid

[1490] Crystallization through eutectic formation was carried out in CPME. The amorphous H-A-P-P-P-S-NH2 solid was stirred overnight in a CPME solution saturated with a co-crystallizing agent under ambient conditions. 96 co-crystallizing agents listed in Table 44 below were examined. No crystalline H-A-P-P-P-S-NH2 eutectics were identified under the conditions examined.

[1491] Table 44. Amorphous H-A-P-P-P-S-NH2 Solid

[1492]

[1493]

[1494] Two crystalline solid forms of the HCl salt of the H-A-P-P-P-S-NH2 tetramer were identified, including H-A-P-P-P-S-NH2 HCl Form A and Form B.

[1495] H-A-P-P-P-S-NH2 HCl Form A was generated through a salt reaction in acetonitrile, which became amorphous after separation / drying. H-A-P-P-P-S-NH2 HCl Form B was generated through a salt reaction in acetone. Based on ion chromatography analysis, both are mono-HCl salts.

[1496] H-A-P-P-P-S-NH2 HCl Form A

[1497] Batch 1

[1498] Under ambient conditions, 1 mL of acetonitrile (ACN) was added to 79.4 mg of the amorphous solid of H-A-P-P-P-S-NH2, which produced a clear colorless solution. With stirring, a solution of 183 μL of 1 N HCl in EtOAc (approx. 1:1.2 molar / molar of peptide:HCl) was added to the peptide solution. The sample was stirred under ambient conditions and soon the whole sample was filled with white solid, which appeared as fine hairlike birefringent needles under a polarized light microscope. An additional 3 mL of ACN was added to the sample, producing a white slurry. The wet solid from the slurry was consistent with H-A-P-P-P-S-HCl Form A, which lost crystallinity after isolation / drying.

[1499] Batch 2

[1500] 3.1 grams of amorphous H-A-P-P-P-S-NH2 TFA salt was dissolved in 50 mL of ACN to form a clear yellow solution. With stirring, a solution of 8 mL of 1 N HCl in EtOAc was added to the peptide solution. The sample was stirred under ambient conditions and a white precipitate appeared soon after stirring until the whole sample became an off-white thick slurry. An additional 150 mL of ACN was added to the sample and stirred under ambient conditions for 2 days. The wet solid from the slurry was consistent with H-A-P-P-P-S-HCl Form A.

[1501] The solid from the slurry was separated by vacuum filtration using a stream of N2 on top of the filter, rinsed on the filter with fresh ACN, and then collected and dried overnight under vacuum at 30 °C. The resulting white solid was amorphous.

[1502] H-A-P-P-P-S-NH2 HCl Form B

[1503] Under ambient conditions, 1 mL of acetone was added to 89.3 mg of the amorphous solid of H-A-P-P-P-S-NH2, which produced a clear colorless solution. With stirring, a solution of 205 μL of 1 N HCl in EtOAc (approx. 1:1.2 molar / molar of peptide:HCl) was added to the peptide solution, which produced a white thick slurry. An additional 2 mL of acetone was added and the sample was stirred under ambient conditions for 2 days. The solid from the slurry was separated by vacuum filtration using a stream of N2 on top of the filter, and the resulting white solid (55 mg) was consistent with HH-A-P-P-P-S-HCl Form B.

[1504] XRPD of H-A-P-P-P-S-NH2 HCl Form A

[1505] The XRPD pattern of crystalline H-A-P-P-P-S-NH2 HCl on a wet sample was obtained using a PANalytical Empyrean diffractometer equipped with a CuKα source and a PIXcel3D 1x1 detector, operating at 45 kV and 40 mA. The sample was scanned between 2 and 40 2θ°, with a step size of 0.0065652 2θ°, for a total of 5788 steps in 3725 seconds. The sample was sandwiched between Etnom films in a sample holder to prevent solvent evaporation, and the analysis was carried out using transmission geometry. The diffraction pattern was collected at ambient temperature.

[1506] The prepared sample of H-A-P-P-P-S-NH2 HCl Form A was characterized by XRPD pattern using CuKα radiation as described above. The sample has the diffraction peaks (2-θ values) described in Table 45 and Figure 17A shown, and particularly has a peak at 5.0° 2-θ and one or more peaks selected from 8.3, 9.7, and 11.2° 2-θ; the tolerance of the diffraction angle is 0.2 degrees.

[1507] Table 45. X-ray powder diffraction peaks of H-A-P-P-P-S-NH2 HCl Form A

[1508]

[1509]

[1510] XRPD from the dry solid of H-A-P-P-P-S-NH2 HCl Form A

[1511] H-A-P-P-P-S-NH2 HCl Form A loses crystallinity after separation / drying. The dried sample exhibits an XRPD pattern with broad halos, with or without broad peaks at low angles, as shown in Figure 17B as shown.

[1512] XRPD of H-A-P-P-P-S-NH2 HCl Form B

[1513] The prepared sample of H-A-P-P-P-S-NH2 HCl Form B was characterized by XRPD pattern using CuKα radiation as described above. The sample has the diffraction peaks (2-θ values) described in Table 46 and Figure 17C shown, and particularly has a peak at 7.2° 2-θ and one or more peaks selected from 5.3, 8.1, 14.4, and 16.2° 2-θ; the tolerance of the diffraction angle is 0.2 degrees.

[1514] Table 46. X-ray powder diffraction peaks of H-A-P-P-P-S-NH2 HCl Form B

[1515]

[1516]

[1517] Example 15: Fmoc-Ser(tBu)-Ser(tBu)-Gly-Ala-Pro-Pro-Pro-Ser(tBu)-NH2

[1518]

[1519] Crystallization studies of Fmoc-Ser(tBu)-Ser(tBu)-Gly-Ala-Pro-Pro-Pro-Ser(tBu)-NH2 (Fmoc-S-S-G-A-P-P-P-S-NH2) were carried out by salt / eutectic formation. A solid form, Fmoc-S-S-G-A-P-P-P-S-NH2 Form A, was identified. Form A represents a class of isostructural solvates and can be generated from a variety of solvent conditions such as acetone, acetonitrile (ACN), methyl acetate (MeOAc), and methyl ethyl ketone (MEK).

[1520] Batch 1

[1521] 0.4 mL of acetone was added to approximately 60 mg of amorphous Fmoc-S-S-G-A-P-P-P-S-NH2 solid, resulting in a clear yellow solution. The solution was stirred for 2 days under ambient conditions, which produced a white slurry. The solid separated from the slurry was consistent with Fmoc-S-S-G-A-P-P-P-S-NH2 Form A. Following a similar procedure, Fmoc-S-S-G-A-P-P-P-S-NH2 Form A was also prepared from other organic solvents including acetonitrile (ACN), methyl acetate (MeOAc), and methyl ethyl ketone (MEK).

[1522] Batch 2

[1523] 3.09 grams of amorphous Fmoc-S-S-G-A-P-P-P-S-NH2 solid was dissolved in 15 mL of MeOAc. The solution was inoculated with Fmoc-S-S-G-A-P-P-P-S-NH2 Form A solid and stirred for 2 days under ambient conditions. An additional 12 mL of MeOAc was added during the process to facilitate stirring. The white solid was separated from the slurry by vacuum filtration using whatman filter paper, rinsed 4 times with 3 mL of fresh MeOAc on the filter, and then collected and dried under vacuum at 30 °C for approximately 3 hours. The resulting white solid (2.4 grams) was consistent with Fmoc-S-S-G-A-P-P-P-S-NH2 Form A.

[1524] XRPD of Fmoc-S-S-G-A-P-P-P-S-NH2 Form A

[1525] The XRPD pattern of crystalline Fmoc-S-S-G-A-P-P-P-S-NH2 Form A was obtained on a Bruker D8 Endeavor X-ray powder diffractometer equipped with a CuKα source and a Linxeye detector, operating at 40 kV and 40 mA. The sample was scanned between 4 and 42 2θ°, with a step size of 0.009 2θ° and a scan rate of 0.5 seconds / step, and using a 0.3° primary slit opening and a 3.9° PSD opening. The powder was filled into a quartz sample holder, and a smooth surface was obtained using a glass slide. The diffraction pattern was collected at ambient temperature and relative humidity. The crystal peak positions were determined in MDI-Jade v7.9.9.

[1526] The prepared sample of Fmoc-S-S-G-A-P-P-P-S-NH2 Form A was characterized by XRPD pattern using CuKα radiation as described above. The sample has the diffraction peaks (2-θ values) described and Figure 18 shown in Table 47, and particularly has a peak at 7.5° 2-θ and one or more peaks selected from 6.1, 8.7, 10.6, 15.0, 16.1, and 18.6° 2-θ; the tolerance of the diffraction angle is 0.2 degrees.

[1527] Table 47. X-ray powder diffraction peaks of Fmoc-S-S-G-A-P-P-P-S-NH2 Form A

[1528]

[1529]

[1530] Example 16: Liquid Phase Peptide Synthesis (LPPS) of Tirzepatide (TZP) Fragment 1

[1531] Tirzepatide fragment 1 (TZP fragment 1) is a peptide consisting of ten amino acids (GPSSGAPPPS). Using the TFA salt of the compound (TFANH2-G-P-S-S-G-A-P-P-S-CONH2), a liquid-phase peptide synthesis (LPPS) strategy for preparing TZP fragment 1 was investigated. The LPPS synthesis of TZP fragment 1 was achieved as follows: coupling Fmoc-GP-OH and NH2-G-P-S-S-G-A-P-P-S-CONH2, followed by deprotection of the Fmoc group and precipitation of the product with a known amount of trifluoroacetic acid.

[1532] Materials

[1533] Fmoc-GP-OH, EDC.HCl, oxyma, diisopropylethylamine (DIPEA), acetonitrile (ACN), isopropyl acetate (IPAc), trifluoroacetic acid (TFA), ethyl acetate (EtOAc), sodium bicarbonate (NaHCO3), diethylamine (DEA), methyl tert-butyl ether (MTBE), heptane, and sodium sulfate were purchased and used without any purification. NH2-G-P-S-S-G-A-P-P-S-CONH2 was synthesized by solid-phase peptide synthesis (SPPS).

[1534] Synthesis of Fmoc-G-P-S-S-G-A-P-P-S-CONH2-Fmoc coupling

[1535] The synthesis of Fmoc-G-P-S-S-G-A-P-P-S-CONH2 (protected TZP fragment 1) was achieved by coupling Fmoc-GP-OH with NH2-G-P-S-S-G-A-P-P-S-CONH2 in acetonitrile / isopropyl acetate (ACN / IPAc).

[1536]

[1537]

[1538] While stirring, 20 ml (20V) of ACN / IPAc (1:3), Fmoc-GP-OH (1.00 equivalent, 1.16 mmol, 456 mg), and oxyma (1.12 equivalents, 1.29 mmol, 184 mg) were added to a round-bottom flask containing a stir bar at room temperature. EDC.HCl (1.26 equivalents, 1.46 mmol, 279 mg) and DIPEA (1.0 equivalent, 1.16 mmol, 199 μL) were added, and the mixture was stirred at room temperature for 10 minutes for pre-activation (the reactants turned yellow). The reaction flask was sonicated for 1 minute, then NH2-G-P-S-S-G-A-P-P-S-CONH2 (1.00 equivalent, 1.16 mmol, 1.00 g) was added all at once, and the mixture was stirred for 1 hour. The pH of the reactants was maintained between 3.5 - 5.5. After completion, the crude mixture was transferred to a separatory funnel, and the flask was rinsed with 2 ml of ethyl acetate (EtOAc) and transferred to the separatory funnel. The mixture was washed twice with 7 ml (7V) of 1M aqueous HCl solution, and the aqueous layer was separated into conical flask 1. Thereafter, it was washed twice with 7 ml (7V) of saturated aqueous NaHCO3 solution each time, and the aqueous layer was drained into conical flask 2. Then it was washed twice with 7 ml of deionized water, and the aqueous layer was drained into conical flask 2. The organic layer was transferred to conical flask 3.

[1539] 20 mL (20 V) of fresh ethyl acetate was added to a separatory funnel to back-extract the aqueous acid and base layers. The organic layers were combined, dried over Na2SO4, and filtered into a flask. The solvent was removed by rotary evaporation to afford 1.032 g (70% yield) of solid Fmoc-G-P-S-S-G-A-P-P-S-CONH2.

[1540] Synthesis of F1-NH2·TFA - Fmoc Deprotection and Subsequent TFA Salification

[1541]

[1542] Fmoc-G-P-S-S-G-A-P-P-S-CONH2 (1.0 equiv, 0.79 mmol, 0.98 g) was dissolved in ACN (3 V, 2.92 mL) in a flask equipped with a stir bar at room temperature. Diethylamine (10 equiv, 0.812 mL) was added and the mixture was stirred at room temperature for 1 h. The solvent was reduced to 2 mL (ca. 2 V) by rotary evaporation and 15 mL (ca. 15 V) of cooled 1:1 MTBE:heptane was added slowly with vortexing to precipitate the product, which was then filtered. The flask was rinsed with more cooled 1:1 MTBE:heptane and filtered.

[1543] The combined solids were dissolved in 2 mL of ACN and transferred to a round-bottom flask and dried completely by rotary evaporation. 2 mL of ACN and a stir bar were added to the material in the round-bottom flask and trifluoroacetic acid (15 equiv, 11.8 mmol, 0.904 mL) was added in one portion at room temperature. The reaction mixture was stirred for 50 min, the stir bar was removed, and 15 mL of cooled 1:1 MTBE:heptane was added slowly with vortexing to give a suspension, which was filtered to afford the solid product. The combined solids were dried by rotary evaporation to give 0.87 g (77% yield) of white solid F1-NH2·TFA.

[1544] Screening of Coupling Agents

[1545] Different coupling agents were screened for the synthesis of Fmoc-G-P-S-S-G-A-P-P-S-CONH2 by coupling Fmoc-GP-OH with NH2-G-P-S-S-G-A-P-P-S-CONH2. Table 48 lists a summary of the coupling agents screened for the reaction.

[1546] Table 48

[1547] 1 2 3 4 5 6 A EEDQ TPTU HATU CDMT TCTU HBTU B HDMA PyBOP T3P HOPO / EDCI TATU TNTU C TOTU PyOxim TCFH COMU PyAOP TSTU D TBTU PyClock DEPBT TOTT HCTU CITU

[1548] In the experiment, a total of 24 coupling agents were screened for the reaction to study which coupling agent was most suitable for the complete conversion of starting materials to products in the shortest time, reducing impurity formation, easy removal of impurities by extraction, being cost-effective and having minimal health hazards.

[1549]

[1550]

[1551] Coupling agent screening was carried out using the 'Dreadnought' equipment set. Fmoc-GP-OH and each coupling agent were dispensed into appropriate wells using Quantos. Stock solutions of 2,4,6-trimethylpyridine in ACN, DEPBT / 2,4,6-trimethylpyridine in ACN, and T3P / 2,4,6-trimethylpyridine in ACN were prepared and dispensed into the corresponding wells in the glove box. The plate was sealed and removed from the glove box, stirred at 800 rpm on a polymer block for 30 minutes, and then moved back into the glove box where a stock solution of NH2-G-P-S-S-G-A-P-P-S-CONH2 was prepared and 1.1 equivalents were dispensed into each vial.

[1552] The plate was removed from the glove box and stirred at room temperature for four hours. LCMS analysis samples were harvested from each vial at 1-hour and 4-hour intervals respectively, diluted and the percentage of conversion at the 1-hour and 4-hour time points was analyzed by LCMS. The results are shown in Figure 19 in.

[1553] Among the 24 coupling agents screened for the reaction, 15 coupling agents showed 100% product formation (100% conversion of the limiting starting material to the product) at the 1-hour interval, while 2 coupling agents showed 100% product formation only at the 4-hour interval. 7 coupling agents did not achieve complete conversion of the limiting starting material to the product even within 4 hours of reaction time.

[1554] Example 17: Solvent Screening Study

[1555] Screen the crystal stability of peptide samples in several organic solvents. For the study, the following four peptide tetramers were used: (i) Boc-Y(tBu)-Aib-E(Me)-G-COOH; (ii) Boc-Y(tBu)-Aib-E(All)-G-COOH; (iii) Boc-Y(tBu)-Aib-E(cHx)-G-COOH; and (iv) Boc-Y(tBu)-Aib-E(Bzl)-G-COOH. The following organic solvents were used for the study: acetone, ACN, MeOH, EtOH, IPA, BuOH, EtOAc, MTBE, THF, MEK, toluene, and water.

[1556] Use an automatic dispenser to dispense 30 mg samples of each peptide tetramer into sample vials (one vial per peptide, tested with each solvent). Then add the solvent to the vial and vortex, adding solvent until the peptide is observed to dissolve or until the solution remains turbid after adding 1000 μL of solvent. Then let the sample stand for 24 hours or longer. The results are shown in Tables 49 - 52, including an indication of which solvent formed crystals of each peptide sample.

[1557] Table 49 - Boc-Y(tBu)-Aib-E(Me)-G-COOH

[1558] Weight (mg) Solvent Total Volume (mL) Solubility (mg / mL) Crystal Formation 30.02 Acetone 0.03 1001 No 30.21 ...

Claims

1. A compound of formula (I), or a salt, solvate or hydrate thereof, wherein R 1 is H or a protecting group; R 2 is H or a protecting group; R 3 is H or a protecting group; and R 4 is H or a protecting group; and wherein R 1 、R 2 、R 3 and R 4 at least one of which is a protecting group.

2. The compound according to claim 1, wherein: a) R1 is H, Fmoc or Boc; b) R2 is H or tert-butyl; c) R4 is H or benzyl; or d) Any combination of (a)-(c).

3. The compound according to any one of claims 1 to 2, wherein R 3 is H, tert-butyl, benzyl, carboxybenzyl, methyl, allyl, cyclohexyl or trityl.

4. A compound according to any one of claims 1 to 3, wherein (a) at least two of R 1 , R 2 , R 3 and R 4 are H; (b) at least two of R 1 , R 2 , R 3 and R 4 are protecting groups; or (c) (a) and (b).

5. The compound according to claim 1, wherein the compound is of a formula selected from:

6. The compound according to any one of claims 1 to 5, wherein: (i) The compound is a solvate, optionally wherein the solvate is produced by methyl tert-butyl ether (MTBE) or a mixture containing MTBE; or (ii) The compound is crystalline, optionally wherein: a) The compound is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2θ of 5.2° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 8.4°, 8.8°, 10.4°, 15.5°, 17.1° and 17.7°; b) The compound is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2θ of 6.1° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 10.3°, 14.9°, 16.8°, 18.1° and 18.2°; or c) The compound is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2θ of 6.2° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 8.9°, 12.3°, 14.9°, 15.4° and 21.8°.

7. A method for synthesizing the compound according to claim 1, the method comprising: - To make a compound of formula (Y prot ) wherein R 1 and R 2 are protecting groups and react with the compound of formula (Aib prot ) wherein R 5 is a protecting group, thereby forming a compound of formula (Y prot -Aib prot ), - Remove the protecting group of R 5 and form a compound of formula (Y prot -Aib) - React a compound of formula (Y prot -Aib) with a compound of formula (E prot ) wherein R 3 is a protecting group, thereby forming a compound of formula (Y prot -Aib-E prot ) - React the compound of formula (Y prot -Aib-E prot ) with the compound of formula (G prot ) wherein R 4 is a protecting group, thereby forming a compound of formula (Y prot -Aib-E prot -G prot ) and optionally - Removal of the protecting group R 1 , R 2 , R 3 and R 4 one or more of.

8. A method for synthesizing a polypeptide, wherein: (i) The polypeptide is SEQ ID NO:1, the method comprising conjugating the compound according to any one of claims 1-5 to the N-terminus of the polypeptide of SEQ ID NO:2 through the C-terminus of the compound; or (ii) The polypeptide is SEQ ID NO:26, the method comprising conjugating the compound according to any one of claims 1-5 to the N-terminus of the polypeptide of SEQ ID NO:27 through the C-terminus of the compound.

9. A compound of formula (II), or a salt, solvate or hydrate thereof, wherein R 6 is H or a protecting group; R 7 is H or a protecting group; R 8 is H or a protecting group; R 9 is H or a protecting group; and R 10 is H or a protecting group; optionally wherein each protecting group is independently selected from Boc, Fmoc, tert-butyl and trityl groups.

10. The compound according to claim 9, wherein a) R 6 is H, Fmoc or Boc; b) R 7 is H or tert-butyl; c) wherein R 8 is H or tert-butyl; d) R 9 is H or tert-butyl; e) R 10 is H or benzyl; or f) Any combination of (a)-(e).

11. The compound according to any one of claims 9 to 10, wherein: (a)R 6 , R 7 , R 8 , R 9 and R 10 at least one of which is a protecting group; or (b) R 6 , R 7 , R 8 , R 9 and R 10 It's H.

12. The compound according to claim 9, wherein the compound has the formula:

13. The compound according to any one of claims 9 to 12, wherein: (i) The compound is a solvate, optionally wherein the solvate is produced by a solvent containing heptane; or (ii) The compound is crystalline, optionally wherein: a) The compound is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2θ of 7.7-7.9° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 5.8°, 10.0°, 10.8-10.9°, 11.3-11.4°, 12.0-12.1°, 12.8°, 14.2-14.4° and 16.8-17.0°; b) The compound is in the form of a crystalline solid, and the crystalline solid is characterized by a peak at a diffraction angle 2θ of 7.3° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 5.1°, 5.7°, 7.6°, 9.5° and 12.4°; c) The compound is in the form of a crystalline solid, and the crystalline solid is characterized by a peak at a diffraction angle 2θ of 7.8° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 8.5°, 11.5°, 12.0°, 12.8°, 14.3°, 15.5°, 20.2° and 23.3°; or d) The compound is in the form of a crystalline solid, and the crystalline solid is characterized by a peak at a diffraction angle 2θ of 8.2 - 8.3° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 5.9°, 7.7°, 9.2°, 10.2°, 11.3°, 13.8 - 13.9°, 15.5 - 15.7°, 17.1° and 18.5°.

14. A method for synthesizing the polypeptide of SEQ ID NO:1, the method comprising (i) conjugating the compound according to any one of claims 9 - 12 to the C-terminus of the polypeptide of SEQ ID NO:3 through the N-terminus of the compound to form the polypeptide of SEQ ID NO:4; and (ii) conjugating the polypeptide of SEQ ID NO:4 to the N-terminus of the polypeptide of SEQ ID NO:5 through its C-terminus.

15. A compound of formula (III), or a salt, solvate or hydrate thereof, wherein R 11 is H or a protecting group; and R 12 is H or a protecting group; optionally wherein each protecting group is independently selected from Boc, Fmoc, tert-butyl and trityl groups.

16. The compound according to claim 15, wherein: a) R 11 is H or tert-butyl; b) R 12 is H or tert-butyl; or c) (a) and (b).

17. A compound according to any one of claims 15 to 16, wherein (a) at least one of R 11 and R 12 is a protecting group; or (b) R 11 and R 12 are H.

18. The compound according to claim 15, wherein the compound is a compound of the following formula: The compound according to any one of claims 15 to 18, wherein: (i) The compound is a solvate; or (ii) The compound is crystalline, optionally wherein: a) The compound is in the form of a crystalline solid, and the crystalline solid is characterized by a peak at a diffraction angle 2θ of 8.0° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 7.0°, 10.3°, 14.1°, 15.2°, 16.7°, 18.0°, 19.0°, 19.7°, 20.8° and 21.9°; b) The compound is in the form of a crystalline solid, and the crystalline solid is characterized by a peak at a diffraction angle 2θ of 9.0° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 5.7°, 9.9°, 16.2°, 17.1°, 17.9°, 18.1°, 18.4°, 18.8°, 19.9°, 20.1° and 22.5°; c) The compound is in the form of a crystalline solid, and the crystalline solid is characterized by a peak at a diffraction angle 2θ of 10.5° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 5.6°, 11.9°, 13.3°, 15.4°, 15.6°, 18.1°, 19.9° and 21.1°; d) The compound is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2θ of 10.7° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 4.9°, 14.8°, 20.3° and 21.5°; e) The compound is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2θ of 10.5° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 5.9°, 10.5°, 10.9°, 12.1°, 13.1°, 15.9°, 17.5°, 20.9°, 21.1° and 21.9°; f) The compound is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2θ of 7.8° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 11.3°, 11.5°, 15.4°, 15.6° and 21.5°; g) The compound is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2θ of 10.0° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 8.1°, 12.5°, 13.5°, 14.7°, 17.8°, 18.8°, 20.0° and 22.4°; or h) The compound is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2θ of 21.1° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 5.6°, 10.5°, 10.8°, 11.9°, 15.4° and 23.8°.

20. A method for synthesizing the polypeptide of SEQ ID NO:1, the method comprising (i) conjugating the compound according to any one of claims 15 - 18 to the C-terminus of the polypeptide of SEQ ID NO:6 through the N-terminus of the compound to form the polypeptide of SEQ ID NO:7; and (ii) conjugating the polypeptide of SEQ ID NO:7 to the N-terminus of the polypeptide of SEQ ID NO:8 through its C-terminus.

21. A compound of formula (IV), or a salt, solvate or hydrate thereof, wherein R 13 is H or a protecting group; R 13* is H or a protecting group; R 14 is H or a protecting group; and R 15 is H or a protecting group; optionally wherein each protecting group is independently selected from Boc, Fmoc, tert-butyl and trityl groups.

22. The compound according to claim 21, wherein a)R 13 is H, Fmoc or Boc; b)R 13* is H; c) R 14 is H or tert-butyl; d) R 15 is H or tert-butyl; or e) Any combination of (a) - (d).

23. A compound according to any one of claims 21 to 22, wherein (a) at least one of R 13 , R 13 *, R 14 and R 15 is a protecting group; or (b) R 13 , R 13* , R 14 and R 15 are H.

24. The compound according to claim 21, wherein the compound has the formula: The compound according to any one of claims 21 to 24, wherein: (i) The compound is a solvate; (ii) The compound is crystalline, optionally wherein: a) The compound is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2θ of 5.1° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 4.3°, 6.1°, 8.0°, 10.1° and 18.7°; or b) The compound is in the form of a crystalline solid, and the crystalline solid is characterized by a peak at a diffraction angle 2θ of 5.2° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 6.0°, 6.7°, 10.0°, 10.3°, 16.4°, 17.8°, 18.3°, 19.4° and 22.4°.

26. A method for synthesizing the polypeptide of SEQ ID NO:1, the method comprising: (i) conjugating the compound according to any one of claims 21-24 to the C-terminus of the polypeptide of SEQ ID NO:9 through the N-terminus of the compound to form the polypeptide of SEQ ID NO:7; and (ii) conjugating the polypeptide of SEQ ID NO:7 to the N-terminus of the polypeptide of SEQ ID NO:8 through its C-terminus.

27. The compound according to claim 21, wherein the compound has the formula: wherein R 54 is H or a protecting group; R 55 is H or a protecting group; and R 56 is H or a protecting group; optionally wherein each protecting group is independently selected from Boc, Fmoc, tert-butyl and trityl groups.

28. The compound according to claim 27, wherein: a) R 54 is H or tert-butyl; b) R 55 is H or tert-butyl; c) R 56 is H or Boc; or d) Any combination of (a)-(c).

29. The compound according to any one of claims 27 to 28, wherein: (a)R 54 , R 55 and R 56 At least one of them is H; (b) R 54 , R 55 and R 56 At least one of (a) and (b) is a protecting group; or (c) (a) and (b).

30. The compound according to claim 27, wherein the compound has the formula: The compound according to any one of claims 27 to 30, wherein: (i) The compound is a solvate, optionally wherein the compound is a solvate generated from acetone; (ii) the compound is a desolvate; or (iii) the compound is crystalline, optionally wherein: a) The compound is in the form of a crystalline solid, and the crystalline solid is characterized by a peak at diffraction angles 2-θ of 5.8° and 18.5° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 8.6°, 9.4°, 12.9°, 13.8°, 17.2° and 19.4°; b) The compound is in the form of a crystalline solid, and the crystalline solid is characterized by peaks at diffraction angles 2-θ of 7.0-7.1° and 7.5-7.7° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 5.3-5.4°, 9.7-9.9° and 14.7-14.9; c) The compound is in the form of a crystalline solid, and the crystalline solid is characterized by a peak at a diffraction angle 2-θ of 8.3° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 6.3°, 11.4°, 14.3° and 16.6°; d) The compound is in the form of a crystalline solid, and the crystalline solid is characterized by a peak at a diffraction angle 2-θ of 7.2° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 6.8°, 8.6°, 15.8° and 18.9°; or e) The compound is in the form of a crystalline solid, and the crystalline solid is characterized by a peak at a diffraction angle 2-θ of 6.1° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 6.3°, 7.8°, 10.0° and 12.4°.

32. A method for synthesizing the compound according to claim 27, the method comprising: - React a compound of formula (Fmoc-G) with a compound of formula (P prot ) to form a compound of formula (Fmoc-G-P prot ) wherein R 57 is a protecting group; - Remove the protecting group R 57 to form the compound of (Fmoc-G-P) - React a compound of formula (Fmoc-G-P) with a compound of formula (S prot2 ) to form a compound of formula (Fmoc-G-P-S prot2 ) wherein R 54 and R 58 are protecting groups; - Removal of the protecting group R 58 to form the compound of (Fmoc-G-P-S prot1 ) -React a compound of formula (Fmoc-G-P-S prot1 ) with a compound of formula (S prot2 ) to form a compound of formula (Fmoc-G-P-S prot1 -S prot2 ) wherein R 55 and R 59 are protecting groups; and - Remove the protecting group R 59 to form (Fmoc-F-G prot1 -S prot1 -S prot1 ) compound - React a compound of formula (Fmoc-G-P-S prot1 -S prot1 ) with a compound of formula (G prot ) to form a compound of formula (Fmoc-G-P-S prot1 -S prot1 -G prot ) wherein R 60 is a protecting group; - Convert the compound of formula (Fmoc-G-P-S prot1 -S prot1 -G prot ) into the compound according to claim 27 - optionally removing one or more protecting groups R 54 , R 55 and R 56 .

33. The method according to claim 32, wherein each protecting group is independently selected from Boc, Fmoc, tert-butyl and trityl groups.

34. A method for synthesizing a polypeptide, wherein: (i) the polypeptide is SEQ ID NO:12, and the method comprises: (i.1) conjugating the compound according to any one of claims 27-30 to the N-terminus of the polypeptide of SEQ ID NO:22 through the C-terminus of the compound, and (i.2) conjugating the resulting compound to the C-terminus of the polypeptide of SEQ ID NO:23 through its N-terminus; (ii) the polypeptide is SEQ ID NO:24, and the method comprises conjugating the compound according to any one of claims 27-30 to the N-terminus of the polypeptide of SEQ ID NO:22 through the C-terminus of the compound; (iii) the polypeptide is SEQ ID NO:16, and the method comprises conjugating the compound according to any one of claims 27-30 to the C-terminus of the polypeptide of SEQ ID NO:25 through the N-terminus of the compound; or (iv) the polypeptide is SEQ ID NO:1, and the method comprises: (iv.1) conjugating the compound according to any one of claims 27-30 to the N-terminus of the polypeptide of SEQ ID NO:8 through the C-terminus of the compound, and (iv.2) conjugating the resulting compound to the C-terminus of the polypeptide of SEQ ID NO:9 through its N-terminus.

35. A compound of formula (V), or a salt, solvate or hydrate thereof, wherein R 16 is H or a protecting group; R 17 is H or a protecting group; R 18 is H or a protecting group; R 19 is H or a protecting group; R 20 is H or a protecting group; and R 21 is H or a protecting group; optionally wherein each protecting group is independently selected from Boc, Fmoc, tert-butyl and trityl groups.

36. The compound according to claim 35, wherein: a)R 16 is H, Fmoc or Boc; b) R 17 is H or tert-butyl; c) R 18 is H or tert-butyl; d) R 19 is H or tert-butyl; e) R 20 is H or tert-butyl; f) R 21 is H or benzyl; or g) Any combination of (a)-(g). The compound according to any one of claims 35 to 36, wherein: (a) R 16 、R 17 、R 18 、R 19 、R 20 and R 21 is at least one protecting group; or (b) wherein R 16 、R 17 、R 18 、R 19 、R 20 and R 21 is H.

38. The compound according to claim 35, wherein the compound has the formula: The compound according to any one of claims 35 to 38, wherein: (i) The compound is a solvate; or (ii) the compound is crystalline, optionally wherein: a) The compound is in the form of a crystalline solid, which is characterized by a peak at a diffraction angle 2θ of 5.8-6.1° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 6.7-7.1° and 8.8-9.0°; or b) The compound is in the form of a crystalline solid, which is characterized by a peak at a diffraction angle 2θ of 5.0-5.2° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 5.3-5.4°, 5.7-6.0°, 6.1-6.2°, 7.6-7.9° and 8.7-9.1°.

40. A method for synthesizing the polypeptide of SEQ ID NO:1, the method comprising (i) conjugating the compound according to any one of claims 35-38 to the C-terminus of the polypeptide of SEQ ID NO:3 through the N-terminus of the compound to form the polypeptide of SEQ ID NO:10; and (ii) conjugating the polypeptide of SEQ ID NO:10 to the N-terminus of the polypeptide of SEQ ID NO:11 through its C-terminus.

41. A compound of formula (VI), or a salt, solvate or hydrate thereof, wherein R 22 is H or a protecting group; R 23 is H or a protecting group; R 24 is H or a protecting group, and R 25 is H or a protecting group; optionally each protecting group is independently selected from Boc, Fmoc, tert-butyl and trityl groups.

42. The compound according to claim 41, wherein a) R 22 is H or Boc; b) R 23 is H or tert-butyl; c) R 24 is H or trityl; d) R 25 is H or tert-butyl; or e) Any combination of (a)-(d). The compound according to any one of claims 41 to 42, wherein: (a) R 22 、R 23 、R 24 and R 25 at least one of which is H; (b) R 22 、R 23 、R 24 and R 25 at least one of which is a protecting group; or (c) (a) and (b).

44. The compound according to claim 41, wherein the compound is of formula (VI-a): The compound according to any one of claims 41 to 44, wherein: (i) The compound is a solvate, optionally wherein the compound is a solvate derived from amyl acetate, a mixture comprising amyl acetate, ethyl acetate or a mixture comprising 2-methyltetrahydrofuran and tert-amyl methyl ether; optionally wherein the mixture comprising amyl acetate is selected from the group consisting of a mixture of amyl acetate and tert-butyl ethyl ether, a mixture of amyl acetate and tert-amyl methyl ether or a mixture of amyl acetate and heptane; (ii) The compound is a desolvate or a partially desolvated compound; or (iii) The compound is crystalline, optionally wherein: a) The compound is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2-θ of 6.3-6.4° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 4.5°, 7.1°, 13.0-13.1°, 15.9-16.0° and 18.4-18.6°; or b) The compound is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2-θ of 7.0-7.2° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 5.0-5.4°, 7.6-7.7°, 8.8-8.9°, 9.4-9.5° and 12.5-12.7°.

46. A method for synthesizing the compound according to claim 41, the method comprising: - React a compound of formula (Y prot ) with a compound of formula (Aib prot ) to form a compound of formula (Y prot -Aib prot ) wherein R 22 , R 23 and R 26 are protecting groups; - Removal of the protecting group R 26 to form a compound of (Y prot -Aib) -Reacting a compound of formula (Y prot -Aib) with a compound of formula (Q prot2 ) to form a compound of formula (Y prot -Aib-Q prot2 ) wherein R 24 and R 27 are protecting groups; - Removal of the protecting group R 27 to form (Y prot -Aib-Q prot1 ) compound - React a compound of formula (Y prot -Aib-Q prot1 ) with a compound of formula (G prot ) to form a compound of formula (VI) wherein R 25 is a protecting group; and - optionally removing one or more protecting groups R 22 , R 23 , R 24 and R 25 .

47. The method according to claim 46, wherein each protecting group is independently selected from Boc, Fmoc, tert-butyl and trityl groups.

48. A method for synthesizing a polypeptide, wherein: (i) the polypeptide is SEQ ID NO:12, the method comprising conjugating the compound according to any one of claims 56 to 59 to the N-terminus of the polypeptide of SEQ ID NO:13 through the C-terminus of the compound; or (ii) the polypeptide is SEQ ID NO:14, the method comprising conjugating the compound according to any one of claims 56 to 59 to the N-terminus of the polypeptide of SEQ ID NO:15 through the C-terminus of the compound.

49. A compound of formula (VII), or a salt, solvate or hydrate thereof, wherein R 28 is H or a protecting group; R 29 is H or a protecting group, and R 30 is H or a protecting group; optionally each protecting group is independently selected from Boc, Fmoc, tert-butyl and trityl groups.

50. The compound according to claim 49, wherein a) R 28 is H or Boc; b) R 29 is H or trityl; c) R 30 is H or tert-butyl; or d) Any combination of (a)-(c). The compound according to any one of claims 49 to 50, wherein: (a)R 28 , R 29 and R 30 At least one of them is H; (b) R 28 , R 29 and R 30 At least one of (a) and (b) is a protecting group; or (c) (a) and (b).

52. The compound according to claim 49, wherein the compound is of formula (VII-a): The compound according to any one of claims 49 to 52, wherein: (i) The compound is a solvate, optionally wherein the compound is a solvate derived from any one of the following: a mixture of acetonitrile and methyl tert-butyl ether, a mixture of nitromethane and methyl tert-butyl ether, a mixture of tetrahydrofuran and methyl tert-butyl ether, methyl acetate, and ethyl acetate; or (ii) The compound is crystalline, optionally wherein: a) The compound is in the form of a crystalline solid, and the crystalline solid is characterized by a peak at a diffraction angle 2-θ of 4.8° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 5.6°, 6.2°, 14.8°, and 15.6°; b) The compound is in the form of a crystalline solid, and the crystalline solid is characterized by a peak at a diffraction angle 2-θ of 5.3° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 7.7°, 10.5°, 11.3°, 11.6°, and 14.4°; or c) The compound is in the form of a crystalline solid, and the crystalline solid is characterized by peaks at diffraction angles 2-θ of 6.2° and 6.9° ± 0.2 degrees in the X-ray powder diffraction pattern.

54. A method for synthesizing the compound of claim 49, the method comprising: - React a compound of formula (H(dnp) prot ) with a compound of formula (Aib prot ) to form a compound of formula (H(dnp) prot -Aib prot ) wherein R 28 and R 31 are protecting groups; - Removal of the protecting group R 31 to form the compound of (H(dnp) prot -Aib) - React a compound of formula (H(dnp) prot -Aib) with a compound of formula (Q prot2 ) to form a compound of formula (H(dnp) prot -Aib-Q prot2 ) where R 29 and R 32 are protecting groups; - Remove the protecting group R 32 to form (H(dnp) prot -Aib-Q prot1 ) compound -Reacting a compound of formula (H(dnp) prot -Aib-Q prot1 ) with a compound of formula (G prot ) to form a compound of formula (VII) wherein R 30 is a protecting group; and - optionally removing one or more protecting groups R 28 , R 29 and R 30 .

55. The method of claim 54, wherein each protecting group is independently selected from Boc, Fmoc, tert-butyl, and trityl groups.

56. A method for synthesizing the polypeptide of SEQ ID NO:16, the method comprising conjugating the compound of any one of claims 49-52 to the N-terminus of the polypeptide of SEQ ID NO:17 through the C-terminus of the compound.

57. A compound of formula (VIII), or a salt, solvate, or hydrate thereof, wherein R 33 is H or a protecting group; R 34 is H or a protecting group; and R 35 is H or a protecting group; optionally wherein each protecting group is independently selected from Boc, Fmoc, tert-butyl and trityl groups.

58. The compound of claim 57, wherein: a) R 33 is H or Boc; b) R 34 is H or trityl; c) R 35 is H or tert-butyl; or d) Any combination of (a)-(c). The compound according to any one of claims 57 or 58, wherein: (a) R 33 、R 34 and R 35 at least one of them is H; (b) R 33 、R 34 and R 35 at least one of them is a protecting group; or (c) (a) and (b).

60. The compound of claim 57, wherein the compound is of formula (VIII-a): The compound according to any one of claims 57 to 60, wherein: (i) The compound is a solvate, optionally a solvate produced from any one of the following: a mixture of tetrahydrofuran and methyl tert-butyl ether, a mixture of tetrahydrofuran and heptane, a mixture of 1,4-dioxane and water, a mixture of ethyl acetate and methyl tert-butyl ether, and a mixture of acetonitrile and methyl tert-butyl ether; or (ii) The compound is crystalline, optionally wherein: a) The compound is in the form of a crystalline solid, and the crystalline solid is characterized by a peak at a diffraction angle 2-θ of 4.7° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 5.5°, 8.2°, 10.1°, 11.8°, 13.3°, 13.6°, and 18.9°; or b) The compound is in the form of a crystalline solid, and the crystalline solid is characterized by a peak at a diffraction angle 2-θ of 5.8° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 5.3°, 8.9°, 9.2°, 15.2°, 18.6°, and 19.5°.

62. A method for synthesizing the compound of claim 57, the method comprising: -Reacting a compound of formula (H(trt) prot ) with a compound of formula (Aib prot ) to form a compound of formula (H(trt) prot -Aib prot ) wherein R 33 and R 36 are protecting groups; - Removal of the protecting group R 36 to form the compound of (H(trt) prot -Aib) - React a compound of formula (H(trt) prot -Aib) with a compound of formula (Q prot2 ) to form a compound of formula (H(trt) prot -Aib-Q prot2 ) wherein R 33 and R 37 are protecting groups; - Removal of the protecting group R 37 to form (H(trt) prot -Aib-Q prot1 ) compound -React a compound of formula (H(trt) prot -Aib-Q prot1 ) with a compound of formula (G prot ) to form a compound of formula (VIII) wherein R 35 is a protecting group; and - optionally removing one or more protecting groups R 33 , R 34 and R 35 .

63. The method of claim 62, wherein each protecting group is independently selected from Boc, Fmoc, tert-butyl, and trityl groups.

64. A method for synthesizing a polypeptide of SEQ ID NO:16, the method comprising conjugating a compound as described in any one of claims 57-60 to the N-terminus of a polypeptide of SEQ ID NO:17 through the C-terminus of the compound.

65. A compound of formula (IX), or a salt, solvate or hydrate thereof, wherein R 38 is H or a protecting group; R 39 is H or a protecting group; R 40 is H or a protecting group; R 41 is H or a protecting group; R 42 is H or a protecting group; and R 43 is H or a protecting group; optionally wherein each protecting group is independently selected from Boc, Fmoc, tert-butyl and trityl groups.

66. The compound according to claim 65, wherein: a) R 38 is H or Fmoc; b) R 39 is H or tert-butyl; c) R 40 is H or tert-butyl; d) R 41 is H or tert-butyl; e) R 42 is H or Boc; f) R 43 is H or tert-butyl; or g) Any combination of (a)-(f). The compound according to any one of claims 65 to 66, wherein: (a) R 38 、R 39 、R 40 、R 41 、R 42 and R 43 is at least one of H; (b) R 38 、R 39 、R 40 、R 41 、R 42 and R 43 is at least one of a protecting group; or (c) (a) and (b).

68. The compound according to claim 65, wherein the compound is of formula (IX-a): The compound according to any one of claims 65 to 68, wherein: (i) The compound is a solvate, optionally a solvate produced from any one of the following: a mixture of methyl acetate and dibutyl ether, a mixture of acetone and dibutyl ether, a mixture of acetonitrile and dibutyl ether, a mixture of ethyl acetate and dibutyl ether, a mixture of methyl acetate and heptane, and a mixture of methyl ethyl ketone and dibutyl ether; (ii) The compound is a desolvated or anhydrous compound; or (iii) The compound is crystalline, optionally wherein: a) The compound is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2-θ of 5.3° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 6.0°, 6.9°, 7.2°, 8.0°, 12.2° and 15.6°; b) The compound is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2-θ of 5.8° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 4.4°, 6.6°, 10.1°, 11.4°, 13.4° and 15.5°; or the compound is in the form of a crystalline solid, the crystalline solid being characterized by peaks at diffraction angles 2-θ of 4.5° and 5.5° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 6.0° and 7.3°.

70. A method for synthesizing the compound according to claim 65, the method comprising: - React the compound of formula (D prot ) with the compound of formula (Y prot2 ) to form a compound of formula (D prot -Y prot2 ) wherein R 38 、R 39 、R 40 and R 44 are protecting groups; - Remove the protecting group R 44 to form the compound of (D prot -Y prot1 ) - React a compound of formula (D prot -Y prot1 ) with a compound of formula (S prot2 ) to form a compound of formula (D prot -Y prot1 -S prot2 ) wherein R 41 and R 45 are protecting groups; - Removal of the protecting group R 45 to form the compound of (D prot - Y prot1 - S prot1 ) - React the compound of formula (D prot -Y prot1 -S prot1 ) with the compound of formula (K prot2 ) to form a compound of formula (IX) wherein R 42 and R 43 are protecting groups; and - optionally removing one or more protecting groups R 38 , R 39 , R 40 , R 41 , R 42 and R 43 .

71. The method according to claim 70, wherein the protecting group is selected from Boc, Fmoc, tert-butyl and trityl groups.

72. A method for synthesizing a polypeptide of SEQ ID NO:16, the method comprising: (i) conjugating a compound as described in any one of claims 65-68 to the N-terminus of a polypeptide of SEQ ID NO:18 through the C-terminus of the compound, and (ii) conjugating the compound according to claim 132 to the C-terminus of a polypeptide of SEQ ID NO:19 through its N-terminus.

73. A compound of formula (X), or a salt, solvate or hydrate thereof, wherein R 46 is H or a protecting group; R 47 is H or a protecting group; R 48 is H or a protecting group; R 49 is H or a protecting group; R 50 is H or a protecting group; and R 51 is H or a protecting group; optionally wherein each protecting group is independently selected from Boc, Fmoc, tert-butyl and trityl groups.

74. The compound according to claim 73, wherein: a) R 46 is H or tert-butyl; b) R 47 is H or tert-butyl; c) R 48 is H or Boc; d) R 49 is H or Fmoc; e) R 50 is H or tert-butyl; f) R 51 is H or tert-butyl; or g) Any combination of (a)-(f). The compound according to any one of claims 73 to 74, wherein: (a) R 46 、R 47 、R 48 、R 49 、R 50 and R 51 is at least one of H; (b) R 46 、R 47 、R 48 、R 49 、R 50 and R 51 is at least one of a protecting group; or (c) (a) and (b).

76. The compound according to claim 73, wherein the compound is of formula (X-a): The compound according to any one of claims 73 to 76, wherein: (i) The compound is a solvate, optionally wherein the compound is a solvate derived from ethanol or isopropanol; (ii) The compound is a desolvate; or (iii) The compound is crystalline, optionally wherein: a) The compound is in the form of a crystalline solid, the crystalline solid being characterized by peaks at diffraction angles 2-θ of 18.1° and 18.7° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 5.7°, 8.7°, 13.7°, 14.3°, 15.9° and 16.2°; b) The compound is in the form of a crystalline solid, the crystalline solid being characterized by peaks at diffraction angles 2-θ of 5.9° and 10.5° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 7.1°, 8.9°, 14.6° and 16.6°; c) The compound is in the form of a crystalline solid, the crystalline solid being characterized by peaks at diffraction angles 2-θ of 7.8° and 20.3° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 5.8°, 15.5° and 19.5°; or d) The compound is in the form of a crystalline solid, the crystalline solid being characterized by peaks at diffraction angles 2-θ of 5.9° and 7.4° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 6.5°, 6.9° and 14.8°.

78. A method for synthesizing the compound according to claim 73, the method comprising: - React the compound of formula (Y prot ) with the compound of formula (S prot2 ) to form a compound of formula (Y prot -S prot2 ) wherein R 46 , R 47 , R 48 and R 52 are protecting groups; - Removal of the protecting group R 52 to form the compound of (Y prot -S prot1 ) - React a compound of formula (Y prot -S prot1 ) with a compound of formula (K prot2 ) to form a compound of formula (Y prot -S prot1 -K prot2 ) wherein R 49 and R 53 are protecting groups; - Remove the protecting group R 53 to form a compound of (Y prot - S prot1 - K prot1 ) - React a compound of formula (Y prot -S prot1 -K prot1 ) with a compound of formula (Y prot2 ) to form a compound of formula (X) wherein R 50 and R 51 are protecting groups; and - optionally removing one or more protecting groups R 46 , R 47 , R 48 , R 49 , R 50 and R 51 .

79. The method according to claim 78, wherein the protecting group is selected from Boc, Fmoc, tert-butyl and trityl groups.

80. A method for synthesizing the polypeptide of SEQ ID NO:16, the method comprising: (i) conjugating the compound according to any one of claims 73-76 to the N-terminus of the polypeptide of SEQ ID NO:20 through the C-terminus of the compound, and (ii) conjugating the resulting compound to the C-terminus of the polypeptide of SEQ ID NO:21 through its N-terminus.

81. A compound of formula (XI), or a salt, solvate or hydrate thereof, wherein R 64 is H or a protecting group; R 65 is H or a protecting group; and R 66 is H or a protecting group; optionally wherein each protecting group is independently selected from Boc, Fmoc, tert-butyl and trityl groups.

82. The compound according to claim 81, wherein: (a) (a) R 64 、R 65 and R 66 and at least one of R b)(b)R 64 , R 65 and R 66 At least one of is a protecting group; or c)(c)(a) and (b).

83. The compound according to claim 81, wherein the compound has the formula: A compound according to any one of claims 81 to 83, wherein: (i) The compound is a solvate; or (ii) The compound is crystalline, optionally wherein the compound is in the form of a crystalline solid, the crystalline solid being characterized by peaks at diffraction angles 2-θ of 6.1° and 8.5° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 5.8°, 16.9°, 18.5°, 18.8°, 19.3° and 20.

9.

85. A compound of formula (XII), or a salt, solvate or hydrate thereof, wherein R 61 is H or a protecting group; R 62 is H or a protecting group; and R 63 is H or a protecting group; optionally wherein each protecting group is independently selected from Boc, Fmoc, tert-butyl and trityl groups.

86. The compound according to claim 85, wherein: a) R 61 is H or tert-butyl; b) R 62 is H or tert-butyl; c) R 63 is H or tert-butyl; d) Any combination of (a)-(c). The compound according to any one of claims 85 to 86, wherein: (a)R 61 , R 62 and R 63 At least one of them is H; (b) R 61 , R 62 and R 63 At least one of (a) and (b) is a protecting group; or (c) (a) and (b).

88. The compound according to claim 85, wherein the compound is of formula (XII-a): The compound according to any one of claims 85 to 88, wherein: (i) The compound is a solvate; (ii) The compound is a desolvate or anhydrous; or (iii) The compound is crystalline, optionally wherein: a) The compound is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2-θ of 11.4° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 6.0°, 8.9°, 12.7°, 13.6°, 14.6°, 17.0° and 18.8°; b) The compound is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2-θ of 10.6° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 7.1°, 12.1°, 13.6°, 14.2°, 15.2°, 16.0° and 16.8°; or c) The compound is in the form of a crystalline solid, the crystalline solid being characterized by peaks at diffraction angles 2-θ of 10.1° and 15.5° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 6.1°, 8.7°, 11.4°, 16.6° and 19.2°.

90. A compound of formula (XIII), or a salt, solvate or hydrate thereof, wherein R 67 is H or a protecting group; R 68 is H or a protecting group; and R 69 is H or a protecting group; optionally wherein each protecting group is independently selected from Boc, Fmoc, tert-butyl and trityl groups.

91. The compound according to claim 90, wherein: a) R 67 is H or tert-butyl; b) R 68 is H or tert-butyl; c) R 69 is H or tert-butyl; d) Any combination of (a)-(c). The compound according to any one of claims 90 to 91, wherein: (a) R 67 , R 68 and R 69 in at least one of them is H; (b) R 67 , R 68 and R 69 in at least one of them is a protecting group; or (c) (a) and (b).

93. The compound according to claim 90, wherein the compound has the formula: The compound according to any one of claims 90 to 93, wherein: (i) The compound is a solvate; (ii) The compound is a desolvate or anhydrous; or (iii) The compound is crystalline, optionally wherein: a) The compound is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2-θ of 5.0° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 8.3, 9.7 and 11.2°; or b) The compound is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2-θ of 7.2° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 5.3, 8.1, 14.4 and 16.2°.

95. A compound of formula (XIV), or a salt, solvate or hydrate thereof, wherein R 70 is H or a protecting group; R 71 is H or a protecting group; R 72 is H or a protecting group; R 73 is H or a protecting group; and R 74 is H or a protecting group; optionally wherein each protecting group is independently selected from Boc, Fmoc, tert-butyl and trityl groups.

96. The compound according to claim 95, wherein: a) R 70 is H, Fmoc or tert-butyl; b) R 71 is H or tert-butyl; c) R 72 is H or tert-butyl; d) R 73 is H or tert-butyl; e) R 74 is H, Fmoc or tert-butyl; f) Any combination of (a)-(e). The compound according to any one of claims 95 to 96, wherein: (a) R 70 、R 71 、R 72 、R 73 and R 74 is at least one of H; (b) R 70 、R 71 、R 72 、R 73 and R 74 is at least one of a protecting group; or (c) (a) and (b).

98. The compound according to claim 95, wherein the compound has the formula: The compound according to any one of claims 95 to 98, wherein: (i) The compound is a solvate; (ii) The compound is a desolvate or anhydrous; or (iii) The compound is crystalline, optionally wherein the compound is in the form of a crystalline solid, the crystalline solid being characterized by a peak at a diffraction angle 2-θ of 7.5° ± 0.2 degrees in the X-ray powder diffraction pattern and one or more peaks selected from 6.1, 8.7, 10.6, 15.0, 16.1 and 18.6°.

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