Oxytocin receptor antagonist or pharmaceutically acceptable salt thereof, and preparation and use thereof

Abstract

Disclosed in the present invention are an atosiban derivative or a pharmaceutically acceptable salt thereof, and the preparation and the use thereof. The structure of the atosiban derivative or the pharmaceutically acceptable salt thereof is as shown in general formula (I) or (II). On the basis of the present invention, fatty acid acylation is performed on an ornithine residue in an atosiban peptide sequence to prepare the derivative, which can effectively improve the antagonistic effect of a parent nucleus. The oxytocin antagonistic effect of the atosiban derivative prepared in the present invention is obviously higher than that of atosiban acetate, and the effect can be effectively used for preventing and / or treating premature delivery when used as an oxytocin antagonist to prepare a drug.

Description

An oxytocin receptor antagonist or a pharmaceutically acceptable salt thereof, and its preparation and application. Technical Field

[0001] This invention relates to an oxytocin antagonist and its preparation and application, and more particularly to an atosiban derivative or its pharmaceutically acceptable salt and its preparation and application. Background Technology

[0002] Currently, the main drugs used to treat premature labor and inhibit uterine contractions include β2-adrenergic receptor agonists, calcium channel blockers, magnesium sulfate, prostaglandin inhibitors, and atosiban derivatives.

[0003] Atosiban acetate is a selective oxytocin receptor antagonist that inhibits uterine contractions by competitively binding to oxytocin receptors on the cell membranes and decidua of uterine smooth muscle cells. Although atosiban acetate has mild side effects and no clear contraindications, its efficacy is relatively weak, requiring hospitalization and continuous high-dose intravenous infusion, resulting in high treatment costs. Summary of the Invention

[0004] Objective of the Invention: The objective of this invention is to provide an atosiban derivative or a pharmaceutically acceptable salt thereof with higher oxytocin antagonistic efficacy. Another objective of this invention is to provide a method for preparing an atosiban derivative or a pharmaceutically acceptable salt thereof, thus solving the problem of how to prepare atosiban derivatives. A third objective of this invention is to provide an application of an atosiban derivative or a pharmaceutically acceptable salt thereof in the preparation of oxytocin antagonists or in the preparation of drugs for the prevention and / or treatment of preterm labor, thus solving the problem of weak antagonistic efficacy of atosiban acetate.

[0005] Technical solution: The present invention provides an atosiban derivative or its pharmaceutically acceptable salt, the compound structural formula of which is as follows:

[0006] The L1 group is one of the following groups:

[0007] The R1, R2, R3, R4, R5, R6, R7, and R8 groups are all independently selected from C 1-6 Directly connected alkyl group, m = 1-10, n = 0 or 1, p = 0 or 1;

[0008] The L2 group is selected from at least one of the following amino acid residues: γ-Glu, α-Glu, β-Asp, α-Asp, γ-D-Glu, α-D-Glu, β-D-Asp, or α-D-Asp;

[0009] The L3 group is selected from C 12-20 Aliphatic monoacid or diacid residues; ornithine residues, L1, L2, and L3 are all linked by amide bonds.

[0010] Preferably, the L1 group is any one of the following groups:

[0011] -HN-(CH2)2-O-(CH2)2-O-CH2-CO-;

[0012] -HN-(CH2)2-O-(CH2)2-O-(CH2)2-O-(CH2)2-O-(CH2)2-CO-;

[0013] -HN-(CH2)2-O-(CH2)2-O-(CH2)2-O-(CH2)2-O-(CH2)2-O-(CH2)2-O-(CH2)2-CO-;

[0014] -HN-(CH2)2-O-(CH2)2-O-(CH2)2-O-(CH2)2-O-(CH2)2-O-(CH2)2-O-(CH2)2-O-(CH2)2-O-(CH2)2-CO-;

[0015] -HN-(CH2)3-O-(CH2)4-O-(CH2)3-NH-CO-;

[0016] -HN-(CH2)3-O-(CH2)4-O-(CH2)3-NH-CO-CH2-O-CH2-CO-;

[0017] -HN-(CH2)3-O-(CH2)4-O-(CH2)3-NH-CO-(CH2)2-CO-;

[0018] -HN-(CH2)2-O-(CH2)2-O-CH2–NH-CO-CH2-O-CH2-CO-;

[0019] -HN-(CH2)3-O-(CH2)2-O-(CH2)2-O-(CH2)3-NH-CO-(CH2)2-CO-;

[0020] -HN-(CH2)3-O-(CH2)2-O-(CH2)2-O-(CH2)3-NH-CO-CH2-O-CH2-CO-;

[0021] -HN-(CH2)2-O-(CH2)2-O-(CH2)2-NH-CO-(CH2)2-CO-;

[0022] -HN-(CH2)2-O-(CH2)2-O-(CH2)2-NH-CO-CH2-O-CH2-CO-;

[0023] -HN-(CH2)3-O-(CH2)2-O-(CH2)2-O-(CH2)2-NH-CO-CH2-O-CH2-CO-;

[0024] -HN-(CH2)3-O-(CH2)2-O-(CH2)3-O-CH2-CO-;

[0025] -HN-(CH2)4-O-(CH2)4-O-CH2-CO-.

[0026] Preferably, the L1 group is -HN-(CH2)2-O-(CH2)2-O-CH2-CO-.

[0027] Preferably, the L2 group is a γ-Glu residue or a β-Asp residue.

[0028] Preferably, the L3 group is C 14 C 16 C 18 Or C 20 Fatty acid or diacid residues.

[0029] In some embodiments, the atosiban derivative comprises any of the following compounds:

[0030] c[Mpa-D-Tyr(OEt)-Ile-Thr-Asn-Cys]-Pro-[Orn-γGlu-CO-(CH2) 12 -CH3]-Gly-NH2, c[Mpa-D-Tyr(OEt)-Ile-Thr-Asn-Cys]-Pro-[Orn-γGlu-CO-(CH2) 14 -CH3]-Gly-NH2, c[Mpa-D-Tyr(OEt)-Ile-Thr-Asn-Cys]-Pro-[Orn-γGlu-CO-(CH2) 16 -CH3]-Gly-NH2, c[Mpa-D-Tyr(OEt)-Ile-Thr-Asn-Cys]-Pro-[Orn-γGlu-CO-(CH2) 18 -CH3]-Gly-NH2, c[Mpa-D-Tyr(OEt)-Ile-Thr-Asn-Cys]-Pro-[Orn-γGlu-CO-(CH2) 12 -COOH]-Gly-NH2, c[Mpa-D-Tyr(OEt)-Ile-Thr-Asn-Cys]-Pro-[Orn-γGlu-CO-(CH2) 14-COOH]-Gly-NH2, c[Mpa-D-Tyr(OEt)-Ile-Thr-Asn-Cys]-Pro-[Orn-γGlu-CO-(CH2) 16 -COOH]-Gly-NH2, c[Mpa-D-Tyr(OEt)-Ile-Thr-Asn-Cys]-Pro-[Orn-γGlu-CO-(CH2) 18 -COOH]-Gly-NH2, c[Mpa-D-Tyr(OEt)-Ile-Thr-Asn-Cys]-Pro-[Orn-2×OEG-γGlu-CO-(CH2) 12 -CH3]-Gly-NH2, c[Mpa-D-Tyr(OEt)-Ile-Thr-Asn-Cys]-Pro-[Orn-2×OEG-γGlu-CO-(CH2) 14 -CH3]-Gly-NH2, c[Mpa-D-Tyr(OEt)-Ile-Thr-Asn-Cys]-Pro-[Orn-2×OEG-γGlu-CO-(CH2) 16 -CH3]-Gly-NH2, c[Mpa-D-Tyr(OEt)-Ile-Thr-Asn-Cys]-Pro-[Orn-2×OEG-γGlu-CO-(CH2) 18 -CH3]-Gly-NH2, c[Mpa-D-Tyr(OEt)-Ile-Thr-Asn-Cys]-Pro-[Orn-2×OEG-γGlu-CO-(CH2) 12 -COOH]-Gly-NH2, c[Mpa-D-Tyr(OEt)-Ile-Thr-Asn-Cys]-Pro-[Orn-2×OEG-γGlu-CO-(CH2) 14 -COOH]-Gly-NH2, c[Mpa-D-Tyr(OEt)-Ile-Thr-Asn-Cys]-Pro-[Orn-2×OEG-γGlu-CO-(CH2) 16 -COOH]-Gly-NH2, c[Mpa-D-Tyr(OEt)-Ile-Thr-Asn-Cys]-Pro-[Orn-2×OEG-γGlu-CO-(CH2) 18 -COOH]-Gly-NH2.

[0031] To obtain the above-mentioned derivatives, the present invention provides a method for preparing an atosiban derivative or a pharmaceutically acceptable salt thereof, comprising any one of the following methods:

[0032] Method 1:

[0033] Method 2:

[0034] Among them, R 10 C 11-19 Straight-chain alkyl or C 11-19 Fatty acid tert-butyl ester group; R 11 It can be methyl or ethyl.

[0035] The molar ratio of compound III to atosiban was 1.0–2.6; the molar ratio of compound IV to atosiban was 1.2–2.7.

[0036] Preferably, the preparation method of compound III is as follows:

[0037] The compound V is either H-Glu-OtBu or H-Asp-OtBu.

[0038] Preferably, the preparation method of compound IV is as follows:

[0039] Compound V is H-Glu-OtBu or H-Asp-OtBu; compound VI is selected from:

[0040] The R 12 The radical group is selected from:

[0041] The R1, R2, R3, R4, R5, R6, R7, and R8 groups are all independently selected from C 1-6 Directly connected alkyl group, m = 1-10, n = 0 or 1, p = 0 or 1.

[0042] The present invention further applies the above-mentioned atosiban derivatives or their pharmaceutically acceptable salts to the preparation of oxytocin antagonists or to the preparation of drugs for the prevention and / or treatment of preterm birth.

[0043] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: The present invention prepares derivatives by fatty acid acylation of ornithine residues in the atosiban peptide sequence, which can effectively improve the antagonistic efficacy of the parent nucleus. The oxytocin antagonistic efficacy of the atosiban derivative prepared by the present invention is significantly higher than that of atosiban acetate. When used as an oxytocin antagonist in the preparation of drugs, it can effectively prevent and / or treat preterm birth. Detailed Implementation

[0044] The technical solution of the present invention will be further described below.

[0045] Methods for the identification, characterization, and purity determination of compounds:

[0046] 1. MS: The mass spectra of the compounds in this invention were obtained using an Agilent LC / MS-6120 single bar mass spectrometer with ESI ionization and molecular weight accurate to one decimal place.

[0047] 2. Purity Determination: The purity of the compounds in this invention was determined using a Thermo Fisher Scientific high-performance liquid chromatograph. The test conditions were as follows: Agilent C18 column (4.6*250mm, 5µm), mobile phase A: 0.1% triethylamine (pH adjusted to 6.8 with phosphoric acid), mobile phase B: acetonitrile, diluent: 50% acetonitrile, flow rate: 1.0 ml / min; detection wavelength: 220 nm; column temperature: 30 °C; injection volume: 20 μl, gradient elution was performed, and purity was characterized by area ratio (%), accurate to two decimal places.

[0048] The abbreviations used in this invention have the following meanings:

[0049] Example 1: c[Mpa-D-Tyr(OEt)-Ile-Thr-Asn-Cys]-Pro-[Orn-γGlu-CO-(CH2)] 12 The structure of [-CH3]-Gly-NH2 (compound 1) is as follows:

[0050] The peptide sequence of atosiban acetate is: c[Mpa-D-Tyr(OEt)-Ile-Thr-Asn-Cys]-Pro-Orn]-Gly-NH2, and its structural formula is as follows:

[0051] Compound 1 was prepared using starting material 1-1 and atosiban acetate via the following route:

[0052] (1) Weigh 500 mg of compound 1-1 and add it to a flask. Add 10 ml of dichloromethane, 310 mg of H-Glu-OtBu, and 310 mg of triethylamine. Stir at 25 ± 5 °C for 2–4 h. TLC analysis shows that almost no raw material remains. Add citric acid aqueous solution to adjust the pH to 5. Separate the liquid and dry the organic phase with anhydrous sodium sulfate. Concentrate to dryness at 25 °C to obtain 610 mg of compound 1-2.

[0053] (2) Weigh 610 mg of compound 1-2 and add it to a flask. Add 5 ml of tetrahydrofuran, 170 mg of NHS, and 335 mg of DCC. Stir at 25 ± 5 °C for 12–17 h. TLC analysis shows that almost no raw material remains. Filter the solution and concentrate the filtrate at 30 °C until no liquid drips out. Add 10 ml of dichloromethane and 10 ml of purified water. Separate the liquid and dry the organic phase with anhydrous sodium sulfate. Concentrate at 30 °C to obtain 700 mg of compound 1-3.

[0054] (3) Weigh 700 mg of compound 1-3 and add it to a flask. Add 10 ml of dichloromethane, 1000 mg of atosiban acetate, and 550 mg of triethylamine. Stir at 25 ± 5 °C for 2–4 h. HPLC analysis shows that almost no raw material remains. Concentrate to dryness at 30 °C to obtain compound 1-4.

[0055] (4) Add 25 mL of trifluoroacetic acid to compounds 1-4 obtained in step (3), stir at 25 ± 5 °C for 24 h, and check the reaction by HPLC to confirm its completeness. Column chromatography purification yielded compound 1 60 mg with a purity of 97.06% and molecular formula C. 62 H 100 N 12 O 16 S2, MS(ESI+) theoretical values: (M / 2+1) + =667.3, measured value: 667.0.

[0056] Example 2: c[Mpa-D-Tyr(OEt)-Ile-Thr-Asn-Cys]-Pro-[Orn-γGlu-CO-(CH2)] 14 The structure of [-CH3]-Gly-NH2 (compound 2) is as follows:

[0057] Compound 2 was prepared using starting material 2-1 and atosiban acetate via the following route:

[0058] (1) Weigh 834 mg of compound 2-1 and add it to a flask. Add 14 mL of dimethyl sulfoxide, 1400 mg of atosiban acetate, and 570 mg of triethylamine. Stir at 25 °C for 2–4 h. HPLC analysis shows that the reaction of the starting material is complete. Column chromatography purification yields 1500 mg of compound 2-2.

[0059] (2) Weigh 500 mg of compound 2-2, add 6 mL of trifluoroacetic acid in an ice bath, stir at 25 °C for 24 h, and check the reaction is complete by HPLC. Column chromatography purification yields 403 mg of compound 2, with a purity of 96.31% and a molecular formula of C2. 64 H 104 N 12 O 16S2, MS(ESI+) theoretical values: (M / 2+1) + =681.3, measured value: 681.4.

[0060] Example 3: c[Mpa-D-Tyr(OEt)-Ile-Thr-Asn-Cys]-Pro-[Orn-γGlu-CO-(CH2)] 16 The structure of [-CH3]-Gly-NH2 (compound 3) is as follows:

[0061] Compound 3 was prepared using starting material 3-1 and atosiban acetate via the following route:

[0062] (1) Weigh 0.5 g of compound 3-1 and add it to a flask. Add 10 ml of dichloromethane, 293 mg of H-Glu-OtBu, and 265 mg of triethylamine. Stir at 25 ± 5 °C for 2–4 h. TLC analysis shows that almost no raw material remains. Adjust the pH to 5 with citric acid aqueous solution, separate the liquids, and dry the organic phase with anhydrous sodium sulfate. Concentrate to dryness at 25 °C to obtain 500 mg of compound 3-2.

[0063] (2) Weigh 490 mg of compound 3-2 and add it to a flask. Add 10 mL of tetrahydrofuran, 134 mg of NHS, and 241 mg of DCC. Stir at 25 ± 5 °C for 12–17 h. TLC analysis shows that almost no raw material remains. Filter the solution and concentrate the filtrate at 30 °C until no liquid drips out. Add 10 mL of dichloromethane and wash the organic phase with 10 mL of purified water and 10 mL of saturated brine. Dry the organic phase with anhydrous sodium sulfate. Concentrate at 30 °C to obtain 550 mg of compound 3-3.

[0064] (3) Weigh 550 mg of compound 3-3 and add it to a flask. Add 10 ml of dichloromethane, 1 ml of dimethyl sulfoxide, 682 mg of atosiban acetate, and 261 mg of triethylamine. Stir at 25 ± 5 °C for 2–4 h. HPLC analysis shows that almost no raw material remains. Concentrate to dryness at 30 °C to obtain compound 3-4.

[0065] (4) Add 10 mL of trifluoroacetic acid to compounds 3-4 obtained in step 3, stir at 25±5℃ for 24 h, and check the reaction by HPLC to confirm its completeness. Column chromatography purification yielded compound 3 350 mg with a purity of 98.95% and a molecular formula of C3. 66 H 108 N 12 O 16 S2, MS(ESI+) theoretical values: (M / 2+1) + =695.4, measured value: 695.0.

[0066] Example 4: c[Mpa-D-Tyr(OEt)-Ile-Thr-Asn-Cys]-Pro-[Orn-γGlu-CO-(CH2)] 18 The structure of [-CH3]-Gly-NH2 (compound 4) is as follows:

[0067] Compound 4 was prepared using starting material 4-1 and atosiban acetate via the following route:

[0068] (1) Weigh 0.5 g of compound 4-1 and add it to a flask. Add 10 ml of tetrahydrofuran, 203 mg of NHS, and 363 mg of DCC. Stir at 25 ± 5 °C for 12–17 h. TLC analysis shows that almost no raw material remains. Filter the solution and concentrate it at 30 °C until no liquid drips out. Add 10 ml of dichloromethane, wash the organic phase with 10 ml of purified water, and wash the organic phase with 10 mL of saturated brine. Dry the organic phase with anhydrous sodium sulfate. Concentrate at 30 °C to obtain 550 mg of compound 4-2.

[0069] (2) Weigh 550 mg of compound 4-2 and add it to a flask. Add 10 ml of dichloromethane, 300 mg of H-Glu-OtBu, and 271 mg of triethylamine. Stir at 25 ± 5 °C for 2–4 h. TLC analysis shows that almost no raw material remains. Adjust the pH to 5 with 10% citric acid aqueous solution, separate the liquids, and dry the organic phase with anhydrous sodium sulfate. Concentrate to dryness at 25 °C to obtain 500 mg of compound 4-3.

[0070] (3) Weigh 500 mg of compound 4-3 and add it to a flask. Add 10 ml of tetrahydrofuran, 127 mg of NHS, and 228 mg of DCC. Stir at 25 ± 5 °C for 12–17 h. TLC analysis shows that almost no raw material remains. Filter the solution and concentrate it at 30 °C until no liquid drips out. Add 10 ml of dichloromethane. Wash the organic phase with 10 ml of purified water and 10 ml of saturated brine. Dry the organic phase with anhydrous sodium sulfate. Concentrate at 30 °C to obtain 470 mg of compound 4-4.

[0071] (4) Weigh 470 mg of compound 4-4 and add it to a flask. Add 10 ml of dichloromethane, 1 ml of dimethyl sulfoxide, 595 mg of atosiban acetate, and 228 mg of triethylamine. Stir at 25 ± 5 °C for 2–4 h. HPLC analysis shows that almost no raw material remains. Concentrate to dryness at 30 °C to obtain compound 4-5.

[0072] (5) Add 10 mL of trifluoroacetic acid to compounds 4-5 obtained in step (4), stir at 25±5℃ for 24 h, and check the reaction by HPLC to confirm its completeness. Column chromatography purification yielded 100 mg of compound 4 with a purity of 98.11% and molecular formula C4. 68 H 112 N 12 O 16 S2, MS(ESI+) theoretical values: (M / 2+1) + =709.4, measured value: 709.2.

[0073] Example 5: c[Mpa-D-Tyr(OEt)-Ile-Thr-Asn-Cys]-Pro-[Orn-γGlu-CO-(CH2)] 12 The structure of [-COOH]-Gly-NH2 (compound 5) is as follows:

[0074] Compound 5 was prepared using starting material 5-1 and atosiban acetate via the following route:

[0075] (1) Weigh 500 mg of compound 5-1 and add it to a flask. Add 10 mL of tetrahydrofuran, 193 mg of NHS, and 360 mg of DCC. Stir at 25 °C for 12–17 h. TLC analysis shows that almost no raw material remains. Filter the solution and concentrate it to dryness. Add 10 mL of dichloromethane and wash the organic phase with 10 mL of purified water and 10 mL of saturated brine. Dry the organic phase with anhydrous sodium sulfate. Concentrate to dryness at 25 °C to obtain 650 mg of compound 5-2.

[0076] (2) Weigh 650 mg of compound 5-2 and add it to a flask. Add 10 mL of dichloromethane, 323 mg of H-Glu-OtBu, and 320 mg of triethylamine. Stir at 25 °C for 2–4 h. TLC analysis shows that almost no raw material remains. Wash the organic phase with 10 mL of 10% citric acid aqueous solution, separate the layers, and dry the organic phase with anhydrous sodium sulfate. Concentrate to dryness at 25 °C to obtain 700 mg of compound 5-3.

[0077] (3) Weigh 700 mg of compound 5-3 and add it to a flask. Add 10 mL of tetrahydrofuran, 163 mg of NHS, and 318 mg of DCC. Stir at 25 °C for 12–17 h. TLC analysis shows that almost no raw material remains. Filter the solution and concentrate it to dryness. Add 10 mL of dichloromethane and wash the organic phase with 10 mL of purified water and 10 mL of saturated brine. Dry the organic phase with anhydrous sodium sulfate. Concentrate to dryness at 25 °C to obtain 750 mg of compound 5-4.

[0078] (4) Weigh 750 mg of compound 5-4 and add it to a flask. Add 10 mL of dichloromethane, 1 mL of dimethyl sulfoxide, 0.81 g of atosiban acetate, and 0.47 g of triethylamine. Stir at 25 °C for 2–4 h. TLC analysis shows that almost no raw material remains. Concentrate to dryness at 25 °C to obtain compound 5-5.

[0079] (5) Under ice-water bath conditions, 110 mL of trifluoroacetic acid was added to compound 5-5 obtained in step (4), and the mixture was stirred at 25 °C for 24 h. The reaction was confirmed to be complete by HPLC, and compound 5 was purified by column chromatography to obtain 330 mg of compound 5 with a purity of 94.94% and a molecular formula of C. 62 H 98 N 12 O 18 S2, MS(ESI+) theoretical values: (M / 2+1) + =682.3, measured value: 682.0.

[0080] Example 6: c[Mpa-D-Tyr(OEt)-Ile-Thr-Asn-Cys]-Pro-[Orn-γGlu-CO-(CH2)] 14 The structure of [-COOH]-Gly-NH2 (compound 6) is as follows:

[0081] Compound 6 was prepared using starting material 6-1 and atosiban acetate via the following route.

[0082] (1) Weigh 500 mg of compound 6-1 and add it to a flask. Add 10 mL of tetrahydrofuran, 177 mg of NHS, and 330 mg of DCC. Stir at 25 °C for 12–17 h. TLC analysis shows that almost no raw material remains. Filter the solution and concentrate it to dryness. Add 10 mL of dichloromethane and wash the organic phase with 10 mL of purified water and 10 mL of saturated brine. Dry the organic phase with anhydrous sodium sulfate. Concentrate to dryness at 25 °C to obtain 500 mg of compound 6-2.

[0083] (2) Weigh 500 mg of compound 6-2 and add it to a flask. Add 10 mL of dichloromethane, 208 mg of H-Glu-OtBu, and 230 mg of triethylamine. Stir at 25 °C for 2–4 h. TLC analysis shows that almost no raw material remains. Wash the organic phase with 10 mL of 10% citric acid aqueous solution, separate the layers, and dry the organic phase with anhydrous sodium sulfate. Concentrate to dryness at 25 °C to obtain 650 mg of compound 6-3.

[0084] (3) Weigh 650 mg of compound 6-3 and add it to a flask. Add 10 mL of tetrahydrofuran, 145 mg of NHS, and 280 mg of DCC. Stir at 25 °C for 12–17 h. TLC analysis shows that almost no raw material remains. Filter the solution and concentrate it to dryness. Add 10 mL of dichloromethane and wash the organic phase with 10 mL of purified water and 10 mL of saturated brine. Dry the organic phase with anhydrous sodium sulfate. Concentrate to dryness at 25 °C to obtain 750 mg of compound 6-4.

[0085] (4) Weigh 700 mg of compound 6-4 and add it to a flask. Add 10 mL of dichloromethane, 1 mL of dimethyl sulfoxide, 780 mg of atosiban acetate, and 450 mg of triethylamine. Stir at 25 °C for 2–4 h. TLC analysis shows that almost no raw material remains. Concentrate to dryness at 25 °C to obtain compound 6-5.

[0086] (5) Under ice-water bath conditions, 110 mL of trifluoroacetic acid was added to compounds 6-5 obtained in step (4), and the mixture was stirred at 25 °C for 24 h. The reaction was confirmed to be complete by HPLC, and compound 6 was purified by column chromatography to obtain 360 mg of compound 6 with a purity of 97.05% and a molecular formula of C. 64 H 102 N 12 O 18 S2, MS(ESI+) theoretical values: (M / 2+1) + =696.3, measured value: 696.0.

[0087] Example 7: c[Mpa-D-Tyr(OEt)-Ile-Thr-Asn-Cys]-Pro-[Orn-γGlu-CO-(CH2)] 16 The structure of [-COOH]-Gly-NH2 (compound 7) is as follows:

[0088] Compound 7 was prepared using starting material 7-1 and atosiban acetate via the following route:

[0089] (1) Weigh 500 mg of compound 7-1 and add it to a flask. Add 10 mL of tetrahydrofuran, 160 mg of NHS, and 307 mg of DCC. Stir at 25 °C for 12–17 h. TLC analysis shows that almost no raw material remains. Filter the solution and concentrate it to dryness. Add 10 mL of dichloromethane and wash the organic phase with 10 mL of purified water and 10 mL of saturated brine. Dry the organic phase with anhydrous sodium sulfate. Concentrate to dryness at 25 °C to obtain 1200 mg of compound 7-2.

[0090] (2) Weigh 600 mg of compound 7-2 and add it to a flask. Add 10 mL of dichloromethane, 235 mg of H-Glu-OtBu, and 260 mg of triethylamine. Stir at 25 °C for 2–4 h. TLC analysis shows that almost no raw material remains. Wash the organic phase with 10 mL of 10% citric acid aqueous solution, separate the layers, and dry the organic phase with anhydrous sodium sulfate. Concentrate to dryness at 25 °C to obtain 750 mg of compound 7-3.

[0091] (3) Weigh 750 mg of compound 7-3 and add it to a flask. Add 10 mL of tetrahydrofuran, 155 mg of NHS, and 326 mg of DCC. Stir at 25 °C for 12–17 h. TLC analysis shows that almost no raw material remains. Filter the solution and concentrate it to dryness. Add 10 mL of dichloromethane and wash the organic phase with 10 mL of purified water and 10 mL of saturated brine. Dry the organic phase with anhydrous sodium sulfate. Concentrate to dryness at 25 °C to obtain 850 mg of compound 7-4.

[0092] (4) Weigh 850 mg of compound 7-4 and add it to a flask. Add 10 mL of dichloromethane, 1 mL of dimethyl sulfoxide, 780 mg of atosiban acetate, and 530 mg of triethylamine. Stir at 25 °C for 2–4 h. TLC analysis shows that almost no raw material remains. Concentrate to dryness at 25 °C to obtain compound 7-5.

[0093] (5) Under ice-water bath conditions, 110 mL of trifluoroacetic acid was added to compound 7-5 obtained in step (4), and the mixture was stirred at 25 °C for 24 h. The reaction was confirmed to be complete by HPLC, and compound 7 was purified by column chromatography to obtain 200 mg of compound 7 with a purity of 96.56% and a molecular formula of C. 66 H 106 N 12 O 18 S2, MS(ESI+) theoretical values: (M / 2+1) + =710.4, measured value: 710.0.

[0094] Example 8: c[Mpa-D-Tyr(OEt)-Ile-Thr-Asn-Cys]-Pro-[Orn-γGlu-CO-(CH2)] 18 The structure of [-COOH]-Gly-NH2 (compound 8) is as follows:

[0095] Compound 8 was prepared using starting material 8-1 and atosiban acetate via the following route:

[0096] (1) Weigh 500 mg of compound 8-1 and add it to a flask. Add 10 mL of tetrahydrofuran, 152 mg of NHS, and 285 mg of DCC. Stir at 25 °C for 12–17 h. TLC analysis shows that almost no raw material remains. Filter the solution and concentrate it to dryness. Add 10 mL of dichloromethane and wash the organic phase with 10 mL of purified water and 10 mL of saturated brine. Dry the organic phase with anhydrous sodium sulfate. Concentrate to dryness at 25 °C to obtain 500 mg of compound 8-2.

[0097] (2) Weigh 500 mg of compound 8-2 and add it to a flask. Add 10 mL of dichloromethane, 185 mg of H-Glu-OtBu, and 210 mg of triethylamine. Stir at 25 °C for 2–4 h. TLC analysis shows that almost no raw material remains. Wash the organic phase with 10 mL of 10% citric acid aqueous solution, separate the layers, and dry the organic phase with anhydrous sodium sulfate. Concentrate to dryness at 25 °C to obtain 650 mg of compound 8-3.

[0098] (3) Weigh 650 mg of compound 8-3 and add it to a flask. Add 10 mL of tetrahydrofuran, 128 mg of NHS, and 253 mg of DCC. Stir at 25 °C for 12–17 h. TLC analysis shows that almost no raw material remains. Filter the solution and concentrate it to dryness. Add 10 mL of dichloromethane and wash the organic phase with 10 mL of purified water and 10 mL of saturated brine. Dry the organic phase with anhydrous sodium sulfate. Concentrate to dryness at 25 °C to obtain 850 mg of compound 8-4.

[0099] (4) Weigh 850 mg of compound 8-4 and add it to a flask. Add 10 mL of dichloromethane, 1 mL of dimethyl sulfoxide, 750 mg of atosiban acetate, and 510 mg of triethylamine. Stir at 25 °C for 2–4 h. TLC analysis shows that almost no raw material remains. Concentrate to dryness at 25 °C to obtain compound 8-5.

[0100] (5) Under ice-water bath conditions, 110 mL of trifluoroacetic acid was added to compound 8-5 obtained in step (4), and the mixture was stirred at 25 °C for 24 h. The reaction was confirmed to be complete by HPLC, and compound 8 was purified by column chromatography to obtain 160 mg of compound 8 with a purity of 97.17% and a molecular formula of C. 68 H 110 N 12 O 18 S2, MS(ESI+) theoretical values: (M / 2+1) + =724.4, measured value: 724.0.

[0101] Example 9: c[Mpa-D-Tyr(OEt)-Ile-Thr-Asn-Cys]-Pro-[Orn-2xOEG-γGlu-CO-(CH2)] 12The structure of [-CH3]-Gly-NH2 (compound 9) is as follows:

[0102] Compound 9 was prepared using starting materials 9-1, 9-4, and atosiban acetate via the following route:

[0103] (1) Weigh 1.5 g of compound 9-1 and add it to a flask. Add 30 ml of dichloromethane, 1.0 g of H-Glu-OtBu, and 0.9 g of triethylamine. Stir at 25 ± 5 °C for 2–4 h. TLC analysis shows that almost no raw material remains. Adjust the pH to 5 with 10% citric acid aqueous solution. Separate the liquid and dry the organic phase with anhydrous sodium sulfate. Concentrate to dryness at 25 °C to obtain 1.5 g of compound 9-2.

[0104] (2) Weigh 0.5 g of compound 9-2 and add it to a flask. Add 10 ml of tetrahydrofuran, 153 mg of NHS, and 274 mg of DCC. Stir at 25 ± 5 °C for 12–17 h. TLC analysis shows that almost no raw material remains. Filter the solution and concentrate the filtrate at 30 °C until no liquid drips out. Add 10 ml of dichloromethane and wash the organic phase with 10 mL of purified water and 10 mL of saturated brine. Dry the organic phase with anhydrous sodium sulfate. Concentrate to dryness at 30 °C to obtain 550 mg of compound 9-3.

[0105] (3) Weigh 550 mg of compound 9-3 and add it to a flask. Add 10 ml of dichloromethane, 365 mg of compound 9-4, and 218 mg of triethylamine. Stir at 25 ± 5 °C for 2–4 h. TLC analysis shows that almost no raw material remains. Adjust the pH to 5 with 10% citric acid aqueous solution, separate the liquids, and dry the organic phase with anhydrous sodium sulfate. Concentrate to dryness at 30 °C to obtain 300 mg of compound 9-5.

[0106] (4) Weigh 300 mg of compound 9-5 and add it to a flask. Add 10 mL of tetrahydrofuran, 58 mg of NHS, and 97 mg of DCC. Stir at 25 ± 5 °C for 12–17 h. TLC analysis shows that almost no raw material remains. Filter the solution and concentrate the filtrate at 30 °C until no liquid drips out. Add 10 mL of dichloromethane and wash the organic phase with 10 mL of purified water and 10 mL of saturated brine. Dry the organic phase with anhydrous sodium sulfate. Concentrate to dryness at 30 °C to obtain 220 mg of compound 9-6.

[0107] (5) Weigh 220 mg of compound 9-6 and add it to a flask. Add 10 ml of dichloromethane, 1 ml of dimethyl sulfoxide, 223 mg of atosiban acetate, and 85 mg of triethylamine. Stir at 25 ± 5 °C for 2–4 h. HPLC analysis shows that almost no raw material remains. Concentrate to dryness at 30 °C to obtain compound 9-7.

[0108] (6) Under ice-water bath conditions, 110 mL of trifluoroacetic acid was added to compounds 9-7 obtained in step 5, and the mixture was stirred at 25 °C for 24 h. HPLC analysis confirmed the completeness of the reaction. Column chromatography purification yielded compound 9, 410 mg, with a purity of 93.54% and a molecular formula of C2. 74 H 122 N 14 O 22 S2, MS(ESI+) theoretical values: (M / 2+1) + =812.4, measured value: 812.0.

[0109] Example 10: c[Mpa-D-Tyr(OEt)-Ile-Thr-Asn-Cys]-Pro-[Orn-2xOEG-γGlu-CO-(CH2)] 14 The structure of [-CH3]-Gly-NH2 (compound 10) is as follows:

[0110] Compound 10 was prepared using starting materials 10⁻¹, 10⁻², and atosiban acetate via the following route:

[0111] (1) Weigh 0.5 g of compound 10⁻¹ and add it to a flask. Add 10 ml of dichloromethane, 315 mg of compound 10⁻², and 187 mg of triethylamine. Stir at 25 ± 5 °C for 2–4 h. TLC analysis shows that almost no raw material remains. Adjust the pH to 5 with 10% citric acid aqueous solution, separate the liquids, and dry the organic phase with anhydrous sodium sulfate. Concentrate to dryness at 25 °C to obtain 550 mg of compound 10⁻³.

[0112] (2) Weigh 10⁻³ 550 mg of compound and add it to a flask. Add 10 mL of tetrahydrofuran, 95 mg of NH₂S, and 170 mg of DCC. Stir at 25 ± 5 °C for 12–17 h. TLC analysis shows that almost no raw material remains. Filter the solution and concentrate the filtrate at 30 °C until no liquid drips out. Add 10 mL of dichloromethane and wash the organic phase with 10 mL of purified water and 10 mL of saturated brine. Dry the organic phase with anhydrous sodium sulfate. Concentrate to dryness at 30 °C to obtain 10⁻⁴ 500 mg of compound.

[0113] (3) Weigh 500 mg of compound 10⁻⁴ and add it to a flask. Add 10 ml of dichloromethane, 1 ml of dimethyl sulfoxide, 454 mg of atosiban acetate, and 174 mg of triethylamine. Stir at 25 ± 5 °C for 2–4 h. HPLC analysis shows that almost no raw material remains. Concentrate to dryness at 30 °C to obtain compound 10⁻⁵.

[0114] (4) Under ice-water bath conditions, 10 mL of trifluoroacetic acid was added to compound 10-5 obtained in step 3, and the mixture was stirred at 25±5℃ for 24 h. HPLC analysis confirmed the completeness of the reaction. Column chromatography purification yielded compound 10 420 mg with a purity of 99.19% and a molecular formula of C10. 76 H 126 N 14 O 22 S2, MS(ESI+) theoretical values: (M / 2+1) + =826.4, measured value: 826.1.

[0115] Example 11: c[Mpa-D-Tyr(OEt)-Ile-Thr-Asn-Cys]-Pro-[Orn-2xOEG-γGlu-CO-(CH2)] 16 The structure of [-CH3]-Gly-NH2 (compound 11) is as follows:

[0116] Compound 11 was prepared using starting materials 11-1, 11-2 and atosiban acetate via the following route:

[0117] (1) Weigh 0.5 g of compound 11-1 and add it to a flask. Add 10 ml of dichloromethane, 293 mg of H-Glu-OtBu, and 265 mg of triethylamine. Stir at 25 ± 5 °C for 2–4 h. TLC analysis shows that almost no raw material remains. Adjust the pH to 5 with 10% citric acid aqueous solution, separate the liquids, and dry the organic phase with anhydrous sodium sulfate. Concentrate to dryness at 25 °C to obtain 500 mg of compound 11-2.

[0118] (2) Weigh 490 mg of compound 11-2 and add it to a flask. Add 10 mL of tetrahydrofuran, 134 mg of NHS, and 241 mg of DCC. Stir at 25 ± 5 °C for 12–17 h. TLC analysis shows that almost no raw material remains. Filter the solution and concentrate the filtrate at 30 °C until no liquid drips out. Add 10 mL of dichloromethane and wash the organic phase with 10 mL of purified water and 10 mL of saturated brine. Dry the organic phase with anhydrous sodium sulfate. Concentrate to dryness at 30 °C to obtain 550 mg of compound 11-3.

[0119] (3) Weigh 430 mg of compound 11-3 and add it to a flask. Add 10 ml of dichloromethane, 234 mg of compound 11-4, and 153 mg of triethylamine. Stir at 25 ± 5 °C for 2–4 h. TLC analysis shows that almost no raw material remains. Adjust the pH to 5 with 10% citric acid aqueous solution, separate the liquids, and dry the organic phase with anhydrous sodium sulfate. Concentrate to dryness at 25 °C to obtain 390 mg of compound 11-5.

[0120] (4) Weigh 390 mg of compound 11-5 and add it to a flask. Add 10 mL of tetrahydrofuran, 65 mg of NHS, and 116 mg of DCC. Stir at 25 ± 5 °C for 12–17 h. TLC analysis shows that almost no raw material remains. Filter the solution and concentrate the filtrate at 30 °C until no liquid drips out. Add 10 mL of dichloromethane and wash the organic phase with 10 mL of purified water and 10 mL of saturated brine. Dry the organic phase with anhydrous sodium sulfate. Concentrate to dryness at 30 °C to obtain 390 mg of compound 11-6.

[0121] (5) Weigh 390 mg of compound 11-6 and add it to a flask. Add 10 ml of dichloromethane, 1 ml of dimethyl sulfoxide, 354 mg of atosiban acetate, and 136 mg of triethylamine. Stir at 25 ± 5 °C for 2–4 h. HPLC analysis shows that almost no raw material remains. Concentrate to dryness at 30 °C to obtain compound 11-7.

[0122] (6) Under ice-water bath conditions, 10 mL of trifluoroacetic acid was added to compound 11-7 obtained in step 3, and the mixture was stirred at 25±5℃ for 24 h. HPLC analysis confirmed the completeness of the reaction. Column chromatography purification yielded 250 mg of compound 11 with a purity of 92.80% and a molecular formula of C1. 78 H 130 N 14 O 22 S2, MS(ESI+) theoretical values: (M / 2+1) + =840.4, measured value: 840.0.

[0123] Example 12: c[Mpa-D-Tyr(OEt)-Ile-Thr-Asn-Cys]-Pro-[Orn-2xOEG-γGlu-CO-(CH2)] 18 The structure of [-CH3]-Gly-NH2 (compound 12) is as follows:

[0124] Compound 12 was prepared using starting materials 12-1, 12-5 and atosiban acetate via the following route:

[0125] (1) Weigh 1.0 g of compound 12-1 and add it to a flask. Add 10 ml of tetrahydrofuran, 410 mg of NHS, and 730 mg of DCC. Stir at 25 ± 5 °C for 12–17 h. TLC analysis shows that almost no raw material remains. Filter the solution and concentrate the filtrate at 30 °C until no liquid drips out. Add 10 ml of dichloromethane and wash the organic phase with 10 mL of purified water and 10 mL of saturated brine. Dry the organic phase with anhydrous sodium sulfate. Concentrate to dryness at 30 °C to obtain 1200 mg of compound 12-2.

[0126] (2) Weigh 1200 mg of compound 12-2 and add it to a flask. Add 10 ml of dichloromethane, 655 mg of H-Glu-OtBu, and 592 mg of triethylamine. Stir at 25 ± 5 °C for 2–4 h. TLC analysis shows that almost no raw material remains. Adjust the pH to 5 with 10% citric acid aqueous solution, separate the liquids, and dry the organic phase with anhydrous sodium sulfate. Concentrate to dryness at 25 °C to obtain 1350 mg of compound 12-3.

[0127] (3) Weigh 1350 mg of compound 12-3 and add it to a flask. Add 20 mL of tetrahydrofuran, 341 mg of NHS, and 621 mg of DCC. Stir at 25 ± 5 °C for 12–17 h. TLC analysis shows that almost no raw material remains. Filter the solution and concentrate it at 30 °C until no liquid drips out. Add 20 mL of dichloromethane and wash the organic phase with 10 mL of purified water and 10 mL of saturated brine. Dry the organic phase with anhydrous sodium sulfate. Concentrate to dryness at 30 °C to obtain 1.6 g of compound 12-4.

[0128] (4) Weigh 1.6 g of compound 12-4 and add it to a flask. Add 10 ml of dichloromethane, 829 mg of compound 12-5, and 543 mg of triethylamine. Stir at 25 ± 5 °C for 2–4 h. TLC analysis shows that almost no raw material remains. Adjust the pH to 5 with 10% citric acid aqueous solution, separate the liquids, and dry the organic phase with anhydrous sodium sulfate. Concentrate to dryness at 25 °C to obtain 1.83 g of compound 12-6.

[0129] (5) Weigh 1.83 g of compound 12-6 and add it to a flask. Add 10 ml of tetrahydrofuran, 294 mg of NHS, and 527 mg of DCC. Stir at 25 ± 5 °C for 12–17 h. TLC analysis shows that almost no raw material remains. Filter the solution and concentrate it at 30 °C until no liquid drips out. Add 20 ml of dichloromethane and wash the organic phase with 10 mL of purified water and 10 mL of saturated brine. Dry the organic phase with anhydrous sodium sulfate. Concentrate to dryness at 30 °C to obtain 1.34 g of compound 12-7.

[0130] (6) Weigh 1.34 g of compound 12-7 and add it to a flask. Add 10 ml of dichloromethane, 1 ml of dimethyl sulfoxide, 1.06 g of atosiban acetate, and 410 mg of triethylamine. Stir at 25 ± 5 °C for 2–4 h. HPLC analysis shows that almost no raw material remains. Concentrate to dryness at 30 °C to obtain compound 12-8.

[0131] (7) Under ice-water bath conditions, 10 mL of trifluoroacetic acid was added to compound 12-8 obtained in step six, and the mixture was stirred at 25±5℃ for 24 h. HPLC analysis confirmed the completeness of the reaction. Column chromatography purification yielded compound 12 380 mg with a purity of 92.13% and a molecular formula of C2. 80 H134 N 14 O 22 S2, MS(ESI+) theoretical values: (M / 2+1) + =854.5, measured value: 854.0.

[0132] Example 13: c[Mpa-D-Tyr(OEt)-Ile-Thr-Asn-Cys]-Pro-[Orn-2xOEG-γGlu-CO-(CH2)] 12 The structure of [-COOH]-Gly-NH2 (compound 13) is as follows:

[0133] Compound 13 was prepared using starting materials 13-1, 13-5 and atosiban acetate via the following route:

[0134] (1) Weigh 500 mg of compound 13-1 and add it to a flask. Add 10 mL of tetrahydrofuran, 193 mg of NHS, and 360 mg of DCC. Stir at 25 °C for 12–17 h. TLC analysis shows that almost no raw material remains. Filter the solution and concentrate it to dryness. Add 10 mL of dichloromethane and wash the organic phase with 10 mL of purified water and 10 mL of saturated brine. Dry the organic phase with anhydrous sodium sulfate. Concentrate to dryness at 25 °C to obtain 650 mg of compound 13-2.

[0135] (2) Weigh 650 mg of compound 13-2 and add it to a flask. Add 10 mL of dichloromethane, 323 mg of H-Glu-OtBu, and 320 mg of triethylamine. Stir at 25 °C for 2–4 h. TLC analysis shows that almost no raw material remains. Wash the organic phase with 10 mL of 10% citric acid aqueous solution, separate the layers, and dry the organic phase with anhydrous sodium sulfate. Concentrate to dryness at 25 °C to obtain 700 mg of compound 13-3.

[0136] (3) Weigh 700 mg of compound 13-3 and add it to a flask. Add 10 mL of tetrahydrofuran, 163 mg of NHS, and 318 mg of DCC. Stir at 25 °C for 12–17 h. TLC analysis shows that almost no raw material remains. Filter the solution and concentrate it to dryness. Add 10 mL of dichloromethane and wash the organic phase with 10 mL of purified water and 10 mL of saturated brine. Dry the organic phase with anhydrous sodium sulfate. Concentrate to dryness at 25 °C to obtain 750 mg of compound 13-4.

[0137] (4) Weigh 750 mg of compound 13-4 and add it to a flask. Add 10 mL of dichloromethane, 0.36 g of compound 13-5, and 0.47 g of triethylamine. Stir at 25 °C for 2–4 h. TLC analysis shows that almost no raw material remains. Wash the organic phase with 10 mL of 10% citric acid aqueous solution, separate the layers, and dry the organic phase with anhydrous sodium sulfate. Concentrate to dryness at 25 °C to obtain 850 mg of compound 13-6.

[0138] (5) Weigh 850 mg of compound 13-6 and add it to a flask. Add 10 mL of tetrahydrofuran, 221 mg of NHS, and 123 mg of DCC. Stir at 25 °C for 12–17 h. TLC analysis shows that almost no raw material remains. Filter the solution and concentrate it to dryness. Add 10 mL of dichloromethane and wash the organic phase with 10 mL of purified water and 10 mL of saturated brine. Dry the organic phase with anhydrous sodium sulfate. Concentrate to dryness at 25 °C to obtain 900 mg of compound 13-7.

[0139] (6) Weigh 900 mg of compound 13-7 and add it to a flask. Add 10 mL of dichloromethane, 1 mL of dimethyl sulfoxide, 400 mg of atosiban acetate, and 400 mg of triethylamine. Stir at 25 °C for 2–4 h. TLC analysis shows that almost no raw material remains. Concentrate to dryness at 25 °C to obtain compound 13-8.

[0140] (7) Under ice-water bath conditions, 10 mL of trifluoroacetic acid was added to compound 13-8 obtained in step six, and the mixture was stirred at 25±5℃ for 24 h. HPLC analysis confirmed the completeness of the reaction. Column chromatography purification yielded compound 13 250 mg with a purity of 95.53% and a molecular formula of C13. 74 H 120 N 14 O 24 S2, MS(ESI+) theoretical values: (M / 2+1) + =827.4, measured value: 827.0.

[0141] Example 14: c[Mpa-D-Tyr(OEt)-Ile-Thr-Asn-Cys]-Pro-[Orn-2xOEG-γGlu-CO-(CH2)] 14 The structure of [-COOH]-Gly-NH2 (compound 14) is as follows:

[0142] Compound 14 was prepared using starting materials 14-1, 14-5 and atosiban acetate via the following route:

[0143] (1) Weigh 500 mg of compound 14-1 and add it to a flask. Add 10 mL of tetrahydrofuran, 177 mg of NHS, and 330 mg of DCC. Stir at 25 °C for 12–17 h. TLC analysis shows that almost no raw material remains. Filter the solution and concentrate it to dryness. Add 10 mL of dichloromethane and wash the organic phase with 10 mL of purified water and 10 mL of saturated brine. Dry the organic phase with anhydrous sodium sulfate. Concentrate to dryness at 25 °C to obtain 500 mg of compound 14-2.

[0144] (2) Weigh 500 mg of compound 14-2 and add it to a flask. Add 10 mL of dichloromethane, 208 mg of H-Glu-OtBu, and 230 mg of triethylamine. Stir at 25 °C for 2–4 h. TLC analysis shows that almost no raw material remains. Wash the organic phase with 10 mL of 10% citric acid aqueous solution, separate the layers, and dry the organic phase with anhydrous sodium sulfate. Concentrate to dryness at 25 °C to obtain 650 mg of compound 14-3.

[0145] (3) Weigh 650 mg of compound 14-3 and add it to a flask. Add 10 mL of tetrahydrofuran, 145 mg of NHS, and 280 mg of DCC. Stir at 25 °C for 12–17 h. TLC analysis shows that almost no raw material remains. Filter the solution and concentrate it to dryness. Add 10 mL of dichloromethane and wash the organic phase with 10 mL of purified water and 10 mL of saturated brine. Dry the organic phase with anhydrous sodium sulfate. Concentrate to dryness at 25 °C to obtain 800 mg of compound 14-4.

[0146] (4) Weigh 800 mg of compound 14-4 and add it to a flask. Add 10 mL of dichloromethane, 345 mg of compound 14-5, and 450 mg of triethylamine. Stir at 25 °C for 2–4 h. TLC analysis shows that almost no raw material remains. Wash the organic phase with 10 mL of 10% citric acid aqueous solution, separate the layers, and dry the organic phase with anhydrous sodium sulfate. Concentrate to dryness at 25 °C to obtain 900 mg of compound 14-6.

[0147] (5) Weigh 900 mg of compound 14-6 and add it to a flask. Add 10 mL of tetrahydrofuran, 125 mg of NHS, and 227 mg of DCC. Stir at 25 °C for 12–17 h. TLC analysis shows that almost no raw material remains. Filter the solution and concentrate it to dryness. Add 10 mL of dichloromethane and wash the organic phase with 10 mL of purified water and 10 mL of saturated brine. Dry the organic phase with anhydrous sodium sulfate. Concentrate to dryness at 25 °C to obtain 950 mg of compound 14-7.

[0148] (6) Weigh 950 mg of compound 14-7 and add it to a flask. Add 10 mL of dichloromethane, 1 mL of dimethyl sulfoxide, 400 mg of atosiban acetate, and 400 mg of triethylamine. Stir at 25 °C for 2–4 h. TLC analysis shows that almost no raw material remains. Concentrate to dryness at 25 °C to obtain compound 14-8.

[0149] (7) Under ice-water bath conditions, 10 mL of trifluoroacetic acid was added to compound 14-8 obtained in step six, and the mixture was stirred at 25±5℃ for 24 h. HPLC analysis confirmed the completeness of the reaction. Column chromatography purification yielded compound 14 220 mg, with a purity of 97.44% and a molecular formula of C14. 76 H 124 N 14 O 24 S2, MS(ESI+) theoretical values: (M / 2+1) + =841.4, measured value: 841.0.

[0150] Example 15: c[Mpa-D-Tyr(OEt)-Ile-Thr-Asn-Cys]-Pro-[Orn-2xOEG-γGlu-CO-(CH2)] 16 The structure of [-COOH]-Gly-NH2 (compound 15) is as follows:

[0151] Compound 15 was prepared using starting materials 15-1, 15-5, and atosiban acetate via the following route:

[0152] (1) Weigh 500 mg of compound 15-1 and add it to a flask. Add 5 mL of dimethyl sulfoxide, 500 mg of atosiban acetate, and 203 mg of triethylamine. Stir at 25 °C for 2–4 h. HPLC analysis shows that the reaction of the starting material is complete. Column chromatography purification yields 850 mg of compound 15-2.

[0153] (2) Weigh 850 mg of compound 15-2 and add it to a flask. Add 64 mL of dichloromethane and 18 mL of trifluoroacetic acid. Stir at 25 °C for 24 h. HPLC detection showed that the reaction was complete. Column chromatography purification yielded 440 mg of compound 15 with a purity of 99.47% and molecular formula C. 78 H 128 N 14 O 24 S2, MS(ESI+) theoretical values: (M / 2+1) + =855.4, measured value: 855.0.

[0154] Example 16: c[Mpa-D-Tyr(OEt)-Ile-Thr-Asn-Cys]-Pro-[Orn-2xOEG-γGlu-CO-(CH2)] 18 The structure of [-COOH]-Gly-NH2 (compound 16) is as follows:

[0155] Compound 16 was prepared using starting materials 16-1, 16-5, and atosiban acetate via the following route:

[0156] (1) Weigh 500 mg of compound 16-1 and add it to a flask. Add 10 mL of tetrahydrofuran, 152 mg of NHS, and 285 mg of DCC. Stir at 25 °C for 12–17 h. TLC analysis shows that almost no raw material remains. Filter the solution and concentrate it to dryness. Add 10 mL of dichloromethane and wash the organic phase with 10 mL of purified water and 10 mL of saturated brine. Dry the organic phase with anhydrous sodium sulfate. Concentrate to dryness at 25 °C to obtain 500 mg of compound 16-2.

[0157] (2) Weigh 500 mg of compound 16-2 and add it to a flask. Add 10 mL of dichloromethane, 185 mg of H-Glu-OtBu, and 210 mg of triethylamine. Stir at 25 °C for 2–4 h. TLC analysis shows that almost no raw material remains. Wash the organic phase with 10 mL of 10% citric acid aqueous solution, separate the layers, and dry the organic phase with anhydrous sodium sulfate. Concentrate to dryness at 25 °C to obtain 650 mg of compound 16-3.

[0158] (3) Weigh 650 mg of compound 16-3 and add it to a flask. Add 10 mL of tetrahydrofuran, 128 mg of NHS, and 253 mg of DCC. Stir at 25 °C for 12–17 h. TLC analysis shows that almost no raw material remains. Filter the solution and concentrate it to dryness. Add 10 mL of dichloromethane and wash the organic phase with 10 mL of purified water and 10 mL of saturated brine. Dry the organic phase with anhydrous sodium sulfate. Concentrate to dryness at 25 °C to obtain 950 mg of compound 16-4.

[0159] (4) Weigh 950 mg of compound 16-4 and add it to a flask. Add 10 mL of dichloromethane, 385 mg of compound 16-5, and 510 mg of triethylamine. Stir at 25 °C for 2–4 h. TLC analysis shows that almost no raw material remains. Wash the organic phase with 10 mL of 10% citric acid aqueous solution. Dry the organic phase with anhydrous sodium sulfate. Concentrate to dryness at 25 °C to obtain 950 mg of compound 16-6.

[0160] (5) Weigh 950 mg of compound 16-6 and add it to a flask. Add 10 mL of tetrahydrofuran, 125 mg of NHS, and 225 mg of DCC. Stir at 25 °C for 12–17 h. TLC analysis shows that almost no raw material remains. Filter the solution and concentrate it to dryness. Add 10 mL of dichloromethane and wash the organic phase with 10 mL of purified water and 10 mL of saturated brine. Dry the organic phase with anhydrous sodium sulfate. Concentrate to dryness at 25 °C to obtain 900 mg of compound 16-7.

[0161] (6) Weigh 900 mg of compound 16-7 and add it to a flask. Add 10 mL of dichloromethane, 1 mL of dimethyl sulfoxide, 400 mg of atosiban acetate, and 400 mg of triethylamine. Stir at 25 °C for 2–4 h. TLC analysis shows that almost no raw material remains. Concentrate to dryness at 25 °C to obtain compound 16-8.

[0162] (7) Under ice-water bath conditions, 110 mL of trifluoroacetic acid was added to compound 16-8 obtained in step six, and the mixture was stirred at 25±5℃ for 24 h. The reaction was confirmed to be complete by HPLC, and compound 16 was purified by column chromatography to obtain 130 mg of compound 16 with a purity of 97.51% and a molecular formula of C16. 80 H 132 N 14 O 24 S2, MS(ESI+) theoretical values: (M / 2+1) + =869.4, measured value: 869.0.

[0163] The oxytocin receptor functionality of compounds 1-16 synthesized in Examples 1-16 was tested.

[0164] I. Experimental Materials

[0165] II. Cell Information

[0166] 1. This invention utilizes stable transgenic cells expressing the OXTR receptor, incubates them with different concentrations of test compounds, and determines the inhibitory effect of the compounds on the OXTR receptor using the FLIPR CALCIUM 6ASSAY KIT kit.

[0167] 2. The OXTR-CHO cell line was cultured in F12 medium containing 10% fetal bovine serum and 0.2 mg / mL Hygromycin B at a temperature of 37°C and a carbon dioxide concentration of 5%.

[0168] 3. Cell passage: Cell passage, resuscitation, and cryopreservation were all performed according to standard methods.

[0169] 4. To maintain the physiological activity of the cells, the degree of cell fusion in the experiment was controlled at around 80%.

[0170] III. Determination of the inhibitory activity of the compound on the OXTR receptor:

[0171] 1. Cell seeding: OXTR-CHO cells were digested and collected, resuspended, counted, and seeded into 384-well cell plates at a density of 1.2 × 10⁻⁶ cells / well. 4 cells / 25μL / well. Incubate at 37℃ in a 5% CO2 incubator for approximately 16-20 hours.

[0172] 2. Day 2: Prepare the Assay Buffer according to the FLIPR Calcium 6 Assay Kit instructions. Freeze-thaw 20×Component A to room temperature, dilute it with Assay Buffer to 1×Loading Buffer, and store at room temperature.

[0173] 3. Remove the culture medium from the cell plate, quickly add 35 μL of 1× loading buffer to each well, centrifuge, and incubate the cell plate at 37°C in the dark for 120 min; prepare the working solutions of the positive compound and the test compound, and transfer 5 μL to the corresponding cell wells, and incubate at 37°C in the dark for 30 min; prepare the agonist, and transfer 20 μL / well to the 384-well compound source plate;

[0174] 4. Place the cell plate, source plate, and pipette tip into the corresponding positions on the FLIPR instrument. Use the FLIPR Tetra to add 10 μL of the diluted compound from step 5 into each well and collect data at wavelengths of 515 nm to 575 nm.

[0175] 5. By plotting the signal value against the compound concentration, curve fitting (IC) is performed using a software nonlinear regression method. 50 calculate.

[0176] 6. Data Analysis

[0177] (1)Z'factor=1-3*(SD Max+SD Min) / (AVG Max-AVG Min);

[0178] (2)CV Max=(SD Max / AVG Max)*100%;

[0179] (3)CV Min=(SD Min / AVG Min)*100%;

[0180] (4) S / B = Signal / Background;

[0181] (5) Calculate the compound IC using the GraphPad nonlinear fitting formula. 50 :

[0182] Y=Bottom+(Top-Bottom) / (1+10^((LogIC50-X)*HillSlope));

[0183] (6)% Inhibition rate formula:

[0184] Mean value of positive controls (atosiban); The mean value of the negative control (DMSO).

[0185] IV. Experimental Results

[0186] Table 1. Results of the test on the oxytocin receptor activity of the compounds of the present invention.

[0187] Table 1 shows the "Test Compound IC" 50 / Atosiban IC 50 "is the IC50 of this compound" 50 Value and Atosiban IC 50 The ratios of the values, as shown in Table 1, are the IC50 values ​​for all tested compounds. 50 The values ​​were all lower than the IC of Atosiban. 50 Values, including the IC50 values ​​of some compounds. 50 The value was significantly lower than that of atosimb, indicating that the oxytocin antagonistic activity of the compound of the present invention was significantly superior to that of atosimb.

Claims

1. An atosiban derivative or a pharmaceutically acceptable salt thereof, characterized in that, The structural formula of the compound is as follows: The L1 group is one of the following groups: The R1, R2, R3, R4, R5, R6, R7, and R8 groups are all independently selected from C 1-6 Directly connected alkyl group, m = 1-10, n = 0 or 1, p = 0 or 1; The L2 group is selected from at least one of the following amino acid residues: γ-Glu, α-Glu, β-Asp, α-Asp, γ-D-Glu, α-D-Glu, β-D-Asp, or α-D-Asp; The L3 group is selected from C 12-20 Aliphatic monoacid or diacid residues; ornithine residues, L1, L2, and L3 are all linked by amide bonds.

2. The atosiban derivative or its pharmaceutically acceptable salt according to claim 1, characterized in that, The L1 group is any one of the following groups: -HN-(CH2)2-O-(CH2)2-O-CH2-CO-; -HN-(CH2)2-O-(CH2)2-O-(CH2)2-O-(CH2)2-O-(CH2)2-CO-; -HN-(CH2)2-O-(CH2)2-O-(CH2)2-O-(CH2)2-O-(CH2)2-O-(CH2)2-O-(CH2)2-CO-; -HN-(CH2)2-O-(CH2)2-O-(CH2)2-O-(CH2)2-O-(CH2)2-O-(CH2)2-O-(CH2)2-O-(CH2)2-O-(CH2)2-CO-; -HN-(CH2)3-O-(CH2)4-O-(CH2)3-NH-CO-; -HN-(CH2)3-O-(CH2)4-O-(CH2)3-NH-CO-CH2-O-CH2-CO-; -HN-(CH2)3-O-(CH2)4-O-(CH2)3-NH-CO-(CH2)2-CO-; -HN-(CH2)2-O-(CH2)2-O-CH2–NH-CO-CH2-O-CH2-CO-; -HN-(CH2)3-O-(CH2)2-O-(CH2)2-O-(CH2)3-NH-CO-(CH2)2-CO-; -HN-(CH2)3-O-(CH2)2-O-(CH2)2-O-(CH2)3-NH-CO-CH2-O-CH2-CO-; -HN-(CH2)2-O-(CH2)2-O-(CH2)2-NH-CO-(CH2)2-CO-; -HN-(CH2)2-O-(CH2)2-O-(CH2)2-NH-CO-CH2-O-CH2-CO-; -HN-(CH2)3-O-(CH2)2-O-(CH2)2-O-(CH2)2-NH-CO-CH2-O-CH2-CO-; -HN-(CH2)3-O-(CH2)2-O-(CH2)3-O-CH2-CO-; -HN-(CH2)4-O-(CH2)4-O-CH2-CO-.

3. The atosiban derivative or its pharmaceutically acceptable salt according to claim 2, characterized in that, The L1 group is -HN-(CH2)2-O-(CH2)2-O-CH2-CO-.

4. The atosiban derivative or its pharmaceutically acceptable salt according to claim 1, characterized in that, The L2 group is a γ-Glu residue or a β-Asp residue.

5. The atosiban derivative or its pharmaceutically acceptable salt according to claim 1, characterized in that, The L3 group is C 14 C 16 C 18 Or C 20 Fatty acid or diacid residues.

6. The atosiban derivative or its pharmaceutically acceptable salt according to claim 1, characterized in that, The atosiban derivatives include any of the following compounds: c[Mpa-D-Tyr(OEt)-Ile-Thr-Asn-Cys]-Pro-[Orn-γGlu-CO-(CH2) 12 -CH3]-Gly-NH2、 c[Mpa-D-Tyr(OEt)-Ile-Thr-Asn-Cys]-Pro-[Orn-γGlu-CO-(CH2) 14 -CH3]-Gly-NH2、 c[Mpa-D-Tyr(OEt)-Ile-Thr-Asn-Cys]-Pro-[Orn-γGlu-CO-(CH2) 16 -CH3]-Gly-NH2、 c[Mpa-D-Tyr(OEt)-Ile-Thr-Asn-Cys]-Pro-[Orn-γGlu-CO-(CH2) 18 -CH3]-Gly-NH2、 c[Mpa-D-Tyr(OEt)-Ile-Thr-Asn-Cys]-Pro-[Orn-γGlu-CO-(CH2) 12 -COOH]-Gly-NH2、 c[Mpa-D-Tyr(OEt)-Ile-Thr-Asn-Cys]-Pro-[Orn-γGlu-CO-(CH2) 14 -COOH]-Gly-NH2、 c[Mpa-D-Tyr(OEt)-Ile-Thr-Asn-Cys]-Pro-[Orn-γGlu-CO-(CH2) 16 -COOH]-Gly-NH2、 c[Mpa-D-Tyr(OEt)-Ile-Thr-Asn-Cys]-Pro-[Orn-γGlu-CO-(CH2) 18 -COOH]-Gly-NH2、 c[Mpa-D-Tyr(OEt)-Ile-Thr-Asn-Cys]-Pro-[Orn-2×OEG-γGlu-CO-(CH2) 12 -CH3]-Gly-NH2、 c[Mpa-D-Tyr(OEt)-Ile-Thr-Asn-Cys]-Pro-[Orn-2×OEG-γGlu-CO-(CH2) 14 -CH3]-Gly-NH2、 c[Mpa-D-Tyr(OEt)-Ile-Thr-Asn-Cys]-Pro-[Orn-2×OEG-γGlu-CO-(CH2) 16 -CH3]-Gly-NH2、 c[Mpa-D-Tyr(OEt)-Ile-Thr-Asn-Cys]-Pro-[Orn-2×OEG-γGlu-CO-(CH2) 18 -CH3]-Gly-NH2、 c[Mpa-D-Tyr(OEt)-Ile-Thr-Asn-Cys]-Pro-[Orn-2×OEG-γGlu-CO-(CH2) 12 -COOH]-Gly-NH2、 c[Mpa-D-Tyr(OEt)-Ile-Thr-Asn-Cys]-Pro-[Orn-2×OEG-γGlu-CO-(CH2) 14 -COOH]-Gly-NH2、 c[Mpa-D-Tyr(OEt)-Ile-Thr-Asn-Cys]-Pro-[Orn-2×OEG-γGlu-CO-(CH2) 16 -COOH]-Gly-NH2、 c[Mpa-D-Tyr(OEt)-Ile-Thr-Asn-Cys]-Pro-[Orn-2×OEG-γGlu-CO-(CH2) 18 -COOH]-Gly-NH2。 7. A method for preparing an atosiban derivative or a pharmaceutically acceptable salt thereof according to any one of claims 1-6, characterized in that, Including any of the following methods: Method 1: Method 2: Among them, R 10 C 11-19 Straight-chain alkyl or C 11-19 Fatty acid tert-butyl ester group; R 11 It can be methyl or ethyl.

8. The method for preparing the atosiban derivative or its pharmaceutically acceptable salt according to claim 7, characterized in that, The preparation method of compound III is as follows: The compound V is either H-Glu-OtBu or H-Asp-OtBu.

9. The method for preparing the atosiban derivative or its pharmaceutically acceptable salt according to claim 7, characterized in that, The preparation method of compound IV is as follows: Compound V is H-Glu-OtBu or H-Asp-OtBu; compound VI is selected from: The R 12 The radical group is selected from: The R1, R2, R3, R4, R5, R6, R7, and R8 groups are all independently selected from C 1-6 Directly connected alkyl group, m = 1-10, n = 0 or 1, p = 0 or 1.

10. The use of an atosiban derivative or a pharmaceutically acceptable salt thereof as described in any one of claims 1-6 in the preparation of an oxytocin antagonist or in the preparation of a medicament for the prevention and / or treatment of preterm labor.

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