CN110862434A

CN110862434A - Compound capable of promoting targeted degradation of TGF- β 1 protein and preparation method and application thereof

Info

Publication number: CN110862434A
Application number: CN201911031379.1A
Authority: CN
Inventors: 卜宪章; 李运之; 粟慧; 冯艳巧; 周斌华
Original assignee: National Sun Yat Sen University
Current assignee: Sun Yat Sen University; National Sun Yat Sen University
Priority date: 2019-10-28
Filing date: 2019-10-28
Publication date: 2020-03-06
Anticipated expiration: 2039-10-28
Also published as: CN110862434B

Abstract

The invention discloses a compound capable of promoting TGF- β 1 protein targeted degradation and a preparation method and application thereof, wherein the compound capable of promoting TGF- β 1 protein targeted degradation is synthesized into thalidomide derivatives by a chemical synthesis method, and then a target compound is synthesized by a standard Fmoc/tBu solid-phase polypeptide synthesis method.

Description

Compound capable of promoting targeted degradation of TGF- β 1 protein and preparation method and application thereof

Technical Field

The invention relates to the field of pharmaceutical chemistry, in particular to a compound capable of promoting TGF- β 1 protein targeted degradation and a preparation method and application thereof.

Background

Transforming growth factor- β (TGF- β) is a secreted cytokine with pleiotropic functions, including regulating Cell proliferation and differentiation, regulating extracellular matrix production and angiogenesis, inducing Cell motility and cellular immunity (see J.Massague, Cell,2008,134,215-230.Y.Yu and X. -H.Feng, Current Opinion in Cell biology,2019,61, 56-63.). TGF- β is thus involved in many physiological and pathological processes such as tumorigenesis, immunosuppression and fibrogenesis (see Y.yue, K.Meng., Y.Pu and X.Zhang, Diabetes research and clinical practice,2017,133,124-130.Y.Hao, D.Baker and P.Ten jke, International J.of tumor sciences,2019,20. TGF-7, TGF-J.J.J.J.J.Cheng, and J.Cheng, and TGF-7, TGF-J.J.J.Cheng, TGF-7, TGF-J.J.J.J.Zhang, TGF-7, TGF-J.J.J.J.Zhang, TGF-J.J.J.J.J.A, TGF-J.Zhang, TGF-7, TGF-J.J.J.J.J.J.A, TGF-7, TGF-J.A, TGF-7, a tumor Cell, a tumor Cell, a tumor Cell, a Cell, a tumor Cell, a Cell.

Molecules targeting TGF- β and its signaling pathway currently have been mainly antisense molecules, antibodies, small molecule kinase inhibitors (y. chen, c.di, x.zhang, j.wang, f.wang, j.f.yan, c.xu, j.zhang, q.zhang, h.li, h.yang and h.zhang, Journal of cellular physiology,2019, DOI:10.1002/jcp.29108.) that act primarily through three strategies, inhibition of TGF- β synthesis, interference with TGF- β binding to the receptor and inhibition of TGF- β mediated downstream gene transduction although these strategies against TGF- β hold promise, many challenges remain, such as affinity for RNA binding, immune related adverse events and drug resistance.

Disclosure of Invention

The invention aims to overcome at least one defect of the prior art and provides a compound capable of promoting TGF- β 1 protein targeted degradation, which plays a role by directly degrading TGF- β 1, has anti-fibrosis and anti-tumor effects theoretically, and is expected to become a new medicine for treating cancer, treating tissue fibrosis and removing skin scar.

Another object of the present invention is to provide a method for preparing the compound capable of promoting the targeted degradation of the TGF- β 1 protein.

Another object of the present invention is to provide the use of the compounds for promoting the targeted degradation of TGF- β 1 protein.

The technical scheme adopted by the invention is as follows:

a compound capable of promoting targeted degradation of TGF- β 1 protein has a structure shown in formula (1):

wherein n is 5,6, 7.

The compound capable of promoting TGF- β 1 protein targeted degradation is structurally divided into three parts, namely a 14 peptide region combined with TGF- β 1, a thalidomide region combined with E3 ubiquitin ligase Cereblon (CRBN) and an alkyl linker region, the molecule is combined with TGF- β 1 and CRBN through two ends respectively, so that the traditional E3 ubiquitin ligase CRBN is pulled to the periphery of TGF- β 1 protein, the recognition of E3 ubiquitin ligase on the target protein TGF- β 1 is enhanced, and the TGF- β 1 is subjected to targeted ubiquitination and is finally degraded through an intracellular ubiquitin-proteasome degradation pathway.

Preferably, n is 5.

The invention firstly synthesizes thalidomide derivatives by a chemical synthesis method, and then synthesizes target compounds by a standard Fmoc/tBu solid-phase polypeptide synthesis method, wherein the preparation method of the compounds capable of promoting TGF- β 1 protein targeted degradation comprises the following steps:

(1) synthesis of thalidomide derivatives:

① adding 1.0eq of 3-hydroxyphthalic anhydride and 1.0eq of 3-aminopyridine-2, 6-dione hydrochloride into a reaction vessel, adding toluene, stirring uniformly, then adding 1.1eq of triethylamine, refluxing at 110 ℃ for 12-18 h, cooling to room temperature after the reaction is finished, spin-drying, passing through a silica gel column dichloromethane/methanol (DCM/MeOH), and finally obtaining an intermediate A;

② intermediate A1.0 eq is dissolved in N, N-Dimethylformamide (DMF) and potassium iodide (KI)0.1eq and potassium bicarbonate (KHCO) are added₃)1.5eq, finally dropwise adding 1.2eq of bromoacetic acid tert-butyl ester, reacting for 3-5 h at 60 ℃, extracting the reaction liquid by using ethyl acetate (EtOAc) and saturated salt water, reserving an ethyl acetate layer, spin-drying, passing through a silica gel column petroleum ether/ethyl acetate (PE/EA), and finally obtaining an intermediate B;

③ dissolving intermediate B1.0eq in trifluoroacetic acid (TFA), stirring at room temperature, reacting for 1.5-2.5 h, and directly spin-drying to obtain intermediate C, namely a thalidomide derivative;

(2) synthesis of target compound:

① the method comprises the steps of taking an O-chloro-trityl chloride resin as a solid support, dissolving 3.0eq of fluorenylmethoxycarbonyl (Fmoc) protected asparagine and 10.0eq of N, N-Diisopropylethylamine (DIEA) in Dichloromethane (DCM), adding the mixture into the resin, reacting at room temperature for 1.5-2.5 h, blocking unreacted sites on the resin with dichloromethane/methanol/N, N-diisopropylethylamine, removing protecting groups with a 5% piperidine N, N-dimethylformamide solution, starting from glutamine, repeatedly condensing and deprotecting 3.0eq of fluorenylmethoxycarbonyl (Fmoc) protected amino acid, 3.0eq of O-benzotriazol-tetramethyluronium Hexafluorophosphate (HBTU), 3.0eq of 1-hydroxybenzotriazole (HOBt) and 6.0eq of N, N-Diisopropylethylamine (DIEA) in a DMF solution until the final synthesis of threonine is completely deprotected;

② linking, namely adding 3.0eq of Fmoc protected 6-aminocaproic acid or 7-aminoheptanoic acid or 3.0eq of 8-aminocaprylic acid, 3.0eq of O-benzotriazole-tetramethylurea hexafluorophosphate, 3.0eq of 1-hydroxybenzotriazole and 10eq of N, N-diisopropylethylamine into a peptide chain combined on resin, reacting at room temperature for 1.5-2.5 h, and deprotecting;

③ Synthesis of target compound, adding thalidomide derivative 3.0eq, O-benzotriazole-tetramethylurea hexafluorophosphate 3.0eq, 1-hydroxybenzotriazole 3.0eq and N, N-diisopropylethylamine 10eq into the resin, reacting at room temperature for 1.5-2.5 h, deprotecting, and finally adding excision liquid trifluoroacetic acid/Phenol/triisopropylsilane/water (TFA/Phenol/i-Pr)₃SiH/H₂O) reacting at room temperature for 2.5-3.5 h, collecting reaction liquid, and concentrating under reduced pressure to obtain a crude product.

Preferably, there is a purification step after the crude product is obtained: purifying by reversed phase high performance liquid chromatography, and freeze drying to obtain pure product.

Preferably, the cleavage solution is TFA/Phenol/i-Pr₃SiH/H₂The volume ratio of O is 88:5:5: 2.

The compound capable of promoting the targeted degradation of the TGF- β 1 protein is applied to tumor treatment.

The compound capable of promoting the targeted degradation of the TGF- β 1 protein is applied to the treatment of tissue fibrosis diseases.

The compound capable of promoting targeted degradation of TGF- β 1 protein is applied to treatment of skin scars.

Compared with the prior art, the compound capable of promoting TGF- β 1 protein targeted degradation is provided, the compound capable of being specifically combined with TGF- β 1 protein targeted ubiquitination degradation TGF- β 1 protein is constructed by applying the targeted ubiquitination degradation protein technology, and the ubiquitination degradation TGF- β 1 protein targeted is proved to be capable of being degraded by TGF- β protein targeted, and TGF- β plays an important role in fibrosis and tumor occurrence and development, so that the compound theoretically has anti-fibrosis and anti-cancer effects, is expected to become a new medicine for treating cancer, treating tissue fibrosis and removing skin scars, and has great scientific value and social value.

Drawings

FIG. 1 is a synthetic scheme of compounds of the present invention that promote targeted degradation of TGF- β 1 protein.

FIG. 2 is an HPLC chromatogram of compound DT-6 of the present invention that promotes the targeted degradation of TGF- β 1 protein.

FIG. 3 is a high-resolution mass spectrum of compound DT-6 of the present invention, which can promote the targeted degradation of TGF- β 1 protein.

FIG. 4 shows H of DT-6, a compound of the invention, which promotes the targeted degradation of TGF- β 1 protein¹NMR spectrum.

FIG. 5 is a graph showing the experimental results of targeted degradation of TGF- β 1 in HepG2 cells by the compound DT-6 capable of promoting targeted degradation of TGF- β 1 protein.

FIG. 6 is a graph showing the results of an Enzyme-Linked ImmunoSorbent Assay (ELISA) Assay for verifying that DT-6 inhibits TGF- β 1 secretion from M2-type macrophages.

FIG. 7 is a recording of Compound DT-6 reversal of M2 macrophage conditioned medium induced HepG2 cell epithelial-mesenchymal transition (EMT) using the EVOS FL color imaging system.

FIG. 8 is a Western Blot procedure demonstrating that Compound DT-6 reverses M2-type macrophage conditioned medium-induced epithelial-mesenchymal transition (EMT) in HepG2 cells.

Detailed Description

The invention is further illustrated by the following specific examples. The following examples are illustrative only and are not to be construed as unduly limiting the invention which may be embodied in many different forms as defined and covered by the summary of the invention. Reagents, compounds and apparatus employed in the present invention are conventional in the art unless otherwise indicated.

The compound capable of promoting TGF- β 1 protein targeted degradation is prepared by firstly synthesizing thalidomide derivatives by a chemical synthesis method and then synthesizing target compounds by a standard Fmoc/tBu solid-phase polypeptide synthesis method, wherein the synthesis route is shown in figure 1, and the structure and the preparation process are explained in detail by combining specific embodiments.

Example 1

A compound DT-6 capable of promoting targeted degradation of TGF- β 1 protein has a structure shown in formula (2):

the specific preparation process of the compound DT-6 capable of promoting the targeted degradation of the TGF- β 1 protein comprises the following steps:

(1) synthesis of thalidomide derivatives:

①, adding 3-hydroxyphthalic anhydride (200mg,1.2mmol,1.0eq) and 3-aminopyridine-2, 6-dione hydrochloride (200mg,1.2mmol,1.0eq) into a round-bottom flask, adding toluene (10mL), stirring uniformly, adding triethylamine (183 uL, 1.32mmol,1.1eq), refluxing at 110 ℃ for 15h, cooling to room temperature, spin-drying, passing through a silica gel column (DCM/MeOH), and finally obtaining an intermediate A;

② intermediate A (196mg,0.71mmol,1.0eq) was dissolved in DMF (5mL) and KI (11.6mg,0.07mmol,0.1eq) and KHCO were added₃(106.6mg,1.06mmol,1.5eq), and finally tert-butyl bromoacetate (124. mu.L, 0.85mmol,1.2eq) was added dropwise and reacted at 60 ℃ for 4 h. Extracting the reaction solution with EtOAc and saturated saline water, reserving an EA layer, spin-drying, and passing through a silica gel column (PE/EA) to finally obtain an intermediate B;

③ intermediate B (195mg,0.5mmol,1.0eq) was dissolved in TFA (2mL), stirred at room temperature, reacted for 2h, and directly spin-dried to give intermediate C, a thalidomide derivative.

(2) Synthesis of target Compound DT-6:

① using o-chloro-trityl chloride resin as solid support, adding Fmoc protected asparagine (3.0eq) and 10.0eq DIEA (N, N-diisopropylethylamine) dissolved in Dichloromethane (DCM) to o-chloro-trityl chloride resin, reacting at room temperature for 2h, blocking unreacted sites on the resin with DCM/MeOH/DIEA (16:3:1), removing protecting groups with 5% piperidine solution in DMF, starting with glutamine, repeating the condensation and deprotection processes with Fmoc protected amino acid (3.0eq), HBTU (3.0eq), HOBt (3.0eq) and DIEA (6.0eq) in DMF until the last amino acid threonine is synthesized;

② Linker ligation of Fmoc protected 6-aminocaproic acid (3.0eq), HBTU (3.0eq), HOBt (3.0eq) and DIEA (10eq) to a resin bound peptide chain, reaction at room temperature for 2h, deprotection;

③ Synthesis of target Compound comprises adding thalidomide derivative (3.0eq), HBTU (3.0eq), HOBt (3.0eq) and DIEA (10eq) into the above resin, reacting at room temperature for 2H, removing protection, adding excision liquid TFA/Phenol/i-Pr3SiH/H2O (88:5:5:2), reacting at room temperature for 3H, collecting reaction solution, concentrating under reduced pressure to obtain crude product, purifying with RP-HPLC (HPLC spectrogram is shown in figure 2), and freeze drying to obtain pure product.

The prepared compound DT-6 capable of promoting the targeted degradation of TGF- β 1 protein is subjected to high resolution mass spectrometry (see figure 3) and H¹Compound confirmation was performed by NMR (see fig. 4).

The specific results of fig. 2, 3 and 4 are as follows:

DT-6,HPLC purity:98.29％,tR＝20.058min。

Exact mass:2006.8754,found[M+2H]²⁺:1004.9431。

¹H NMR(600MHz,DMSO)δ11.13(s,1H),10.76(s,1H),8.14-7.69(m,16H),7.52(dd,J＝22.4,7.6Hz,2H),7.39(d,J＝8.7Hz,2H),7.31(d,J＝8.1Hz,1H),7.17(s,1H),7.13(s,1H),7.04(t,J＝7.5Hz,1H),6.96(t,J＝7.4Hz,1H),6.92(s,1H),6.75(s,1H),5.13(dd,J＝12.9,5.4Hz,1H),4.77(s,2H),4.52-4.48(m,3H),4.34-4.23(m,9H),4.16-3.97(m,3H),3.68-3.56(m,3H),3.15-3.10(m,3H),2.99-2.87(m,2H),2.72(dd,J＝16.5,5.0Hz,1H),2.62-2.55(m,2H),2.53-2.38(m,4H),2.23-2.17(m,2H),2.14-2.09(m,2H),2.06-2.00(m,7H),1.97-1.56(m,9H),1.52-1.34(m,9H),1.23(m,11H),1.05-1.00(m,5H),0.86(d,J＝6.6Hz,3H),0.82(d,J＝6.5Hz,3H),0.80-0.67(m,12H)。

example 2

In order to demonstrate the activity of the compound DT-6 which can promote targeted degradation of the TGF- β 1 protein, the Western Blot method is adopted to verify that the compound DT-6 can degrade TGF- β 1 in HepG2 cells.

HepG2 cells according to 2X 10⁴Cells were seeded in 6-well plates per well, and after 12 hours of cell attachment, cells were treated with DT-6 to give final concentrations of 0.01. mu.M, 0.05. mu.M, 0.1. mu.M, 0.5. mu.M, 1. mu.M compound at 37 ℃ with 5% CO₂After culturing for 12 hours in the incubator, the cells are collected, proteins are extracted by the RIPA method, loading buffer is added after quantification until denaturation, and then the expression of TGF- β 1 is detected by the WesternBlot method.

The experimental result of TGF- β 1 in targeted degradation HepG2 cells of a compound DT-6 capable of promoting targeted degradation of TGF- β 1 protein is shown in a graph in FIG. 5. from FIG. 5, after DT-6 can degrade TGF- β 1, 0.01 mu M, 0.05 mu M, 0.1 mu M, 0.5 mu M and 1 mu M in HepG2 cells and acts on HepG2 cells for 12h, compared with a control group, the content of TGF- β 1 in a DT-6 acting group with 0.1 mu M, 0.5 mu M and 1 mu M is obviously reduced, and the activity of the TGF- β 1 protein targeted degradation compound is proved.

Example 3

In order to prove the activity of the compound DT-6 for promoting the targeted degradation of the TGF- β 1 protein to target and degrade the TGF- β 1 protein compound, when DT-6 is proved to degrade intracellular TGF- β 1, the amount of TGF- β 1 secreted to the outside of the cell is also reduced, the example adopts Enzyme-Linked ImmunoSorbent Assay (ELISA) to verify that the compound DT-6 inhibits the secretion of TGF- β 1 in M2 type macrophages, and the specific steps are as follows:

macrophage M2 at 4X 10⁶Cells were seeded per well in 6-well plates and after 12h adherence, compound treatment M2 typeMacrophages with final concentrations of 50 μ M and 20 μ M compound and 50 μ M compound P144, control group without drug treatment at 37 deg.C 5% CO₂After 24 hours of culture in the incubator, cell supernatants were collected and assayed for TGF- β 1 content in each group of supernatants according to the ELISA kit instructions.

The experimental result of the compound DT-6 inhibiting TGF- β 1 secretion by M2 type macrophages through enzyme linked immunosorbent assay verification in the embodiment is shown in figure 6. from figure 6, the content of TGF- β 1 of the DT-6 action group is obviously reduced and has concentration dependence, and the DT-6 can reduce the content of TGF- β 1 secreted outside cells.

Example 4

To demonstrate that the compound DT-6 capable of promoting the targeted degradation of TGF- β 1 protein can reverse the tumor cell EMT (epithelial-mesenchymal transition) caused by TGF- β 1 after targeted degradation of TGF- β 1, the EVOS FL color imaging system was used in this example to record that compound DT-6 reverses M2 macrophage conditioned medium-induced HepG2 cell epithelial-mesenchymal transition (EMT) as follows:

macrophage M2 at 4X 10⁶Cells were seeded per well in 6-well plates and 12h after adherence M2-type macrophages were treated with compound to final concentrations of 50. mu.M and 20. mu.M and compound P144 to 50. mu.M, control groups were left untreated with 5% CO at 37 ℃ with no drug treatment₂After 24 hours of culture in the incubator of (1), cell supernatants were collected to obtain conditioned medium, and HepG2 cells were cultured at 2X 10 in advance for 12 hours⁴Inoculating each cell in 6-well plate, treating HepG2 cells with conditioned medium after adherence, adding culture medium with corresponding volume to blank control group, adding 10ng/mL human recombinant TGF- β 1 protein to positive control group, and adding 5% CO at 37 deg.C₂After 48 hours of incubation in the incubator of (1), the cell status was recorded by the EVOS FL color imaging system.

The results of this example using the EVOS FL color imaging system to record that Compound DT-6 reversed the epithelial-to-mesenchymal transition (EMT) of HepG2 cells induced by M2-type macrophage conditioned medium are shown in FIG. 7. from FIG. 7, it can be seen that HepG2 cells cultured from the supernatant of the above M2-type macrophages showed fusiform and slender morphology of the supernatant without compound treatment and of the HepG2 cells treated with TGF- β 1, indicating that EMT occurred in the cells, while the morphology of HepG2 cells cultured from the supernatant containing DT-6 treatment showed circular shape, indicating that Compound DT-6 reversed the EMT of tumor cells induced by TGF- β 1.

Example 5

To further demonstrate that the compound can reverse the tumor cell EMT caused by TGF- β 1 after targeting and degrading TGF- β 1, the example utilizes a western blot method to detect a marker protein of the HepG2 intracellular EMT, which is described in the following

Macrophage M2 at 4X 10⁶Cells were seeded per well in 6-well plates and 12h after attachment M2-type macrophages were treated with compound to give final concentrations of 50. mu.M, 20. mu.M and 5. mu.M compound P144 of 50. mu.M, and no drug treatment was given to the control group at 37 ℃ with 5% CO₂After 24 hours of culture in the incubator of (1), cell supernatants were collected to obtain conditioned medium, and HepG2 cells were cultured at 2X 10 in advance for 12 hours⁴Inoculating each cell in 6-well plate, treating HepG2 cells with conditioned medium after adherence, adding culture medium with corresponding volume to blank control group, adding 10ng/mL human recombinant TGF- β 1 protein to positive control group, and adding 5% CO at 37 deg.C₂After culturing for 48 hours in the incubator, collecting cells, extracting proteins by a RIPA method, adding a loading buffer after quantification, boiling until the cells are denatured, and detecting the expression of EMT marker protein E-cadherin (marker protein of epithelial cells) and Vimentin (marker protein of interstitial cells) by a Western Blot method.

The result of this example using Western Blot to verify that Compound DT-6 reverses epithelial-mesenchymal transition (EMT) of HepG2 cells induced by M2 type macrophage conditioned medium is shown in FIG. 8. from FIG. 8, it can be seen that when HepG2 cells were cultured with supernatant of M2 type macrophage treated without compound, E-cadherin decreased and vimentin increased, indicating that HepG2 cells develop EMT, and when HepG2 cells were cultured with supernatant of M2 type macrophage treated with DT-6 compound, E-cadherin increased and vimentin decreased, and there was concentration dependence, further demonstrating that pGDT-6 can reverse the EMT of tumor cells induced by TGF- β 1 after targeted degradation of TGF- β 1.

It is worth to be noted that the compound capable of promoting the targeted degradation of the TGF- β 1 protein is not limited to GT-6, but includes compounds with the structure shown in formula (1), specifically:

the processes for preparing DT-6, DT-7 and DT-8 are all in the linking step of ② Linker synthesis of the target compound in step (2), except that Fmoc protected 6-aminocaproic acid or 7-aminoheptanoic acid or 8-aminocaprylic acid is added to the peptide chain bound to the resin, and the structure is shown in formula (3):

DT-6, DT-7 and DT-8 were prepared with the difference that n was different. Based on the experimental results of DT-6, DT-7 and DT-8 have similar performances, and the invention does not further verify the performances of DT-7 and DT-8.

It should be understood that the above-mentioned embodiments of the present invention are only examples for clearly illustrating the technical solutions of the present invention, and are not intended to limit the specific embodiments of the present invention. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention claims should be included in the protection scope of the present invention claims.

Claims

1. A compound capable of promoting targeted degradation of TGF- β 1 protein is characterized by having a structure shown in formula (1):

wherein n is 5,6, 7.

2. The compound for promoting targeted degradation of a TGF- β 1 protein according to claim 1, wherein n is 5.

3. The method for preparing a compound capable of promoting targeted degradation of TGF- β 1 protein according to claim 1 or 2, comprising the steps of:

(1) synthesis of thalidomide derivatives:

① adding 1.0eq of 3-hydroxyphthalic anhydride and 1.0eq of 3-aminopyridine-2, 6-dione hydrochloride into a reaction vessel, adding toluene, stirring uniformly, then adding 1.1eq of triethylamine, refluxing and reacting at 110 ℃ for 12-18 h, cooling to room temperature after the reaction is finished, spin-drying, passing through a silica gel column dichloromethane/methanol, and finally obtaining an intermediate A;

② dissolving the intermediate A1.0 eq in N, N-dimethylformamide, adding potassium iodide 0.1eq and potassium bicarbonate 1.5eq, finally dropwise adding tert-butyl bromoacetate 1.2eq, reacting at 60 ℃ for 3-5 h, extracting the reaction solution with ethyl acetate and saturated salt water, reserving an ethyl acetate layer, spin-drying, passing through a silica gel column petroleum ether/ethyl acetate, and finally obtaining an intermediate B;

③ dissolving the intermediate B1.0eq in trifluoroacetic acid, stirring at room temperature, reacting for 1.5-2.5 h, and directly carrying out spin drying to obtain an intermediate C, namely a thalidomide derivative;

(2) synthesis of target compound:

① using O-chloro-trityl chloride resin as solid support, 3.0eq fluorenylmethoxycarbonyl protected asparagine and 10.0eq N, N-diisopropylethylamine dissolved in dichloromethane and then added into O-chloro-trityl chloride resin, reacting at room temperature for 1.5-2.5 h, sealing unreacted sites on the resin with dichloromethane/methanol/N, N-diisopropylethylamine, removing protective groups with 5% piperidine N, N-dimethylformamide solution, repeating condensation and deprotection processes with fluorenylmethoxycarbonyl protected amino acid 3.0eq, O-benzotriazol-tetramethylurea hexafluorophosphate 3.0eq, 1-hydroxybenzotriazole 3.0eq and N, N-diisopropylethylamine 6.0eq N, N-dimethylformamide solution from glutamine until the final amino acid threonine synthesis is finished;

② linking, namely adding 3.0eq of 6-aminocaproic acid or 7-aminoheptanoic acid or 8-aminocaprylic acid protected by fluorenylmethoxycarbonyl into a peptide chain combined on resin, 3.0eq of O-benzotriazole-tetramethylurea hexafluorophosphate, 3.0eq of 1-hydroxybenzotriazole and 10eq of N, N-diisopropylethylamine at room temperature, reacting for 1.5-2.5 h, and deprotecting;

③ Synthesis of a target compound, adding 3.0eq of thalidomide derivative, 3.0eq of O-benzotriazole-tetramethylurea hexafluorophosphate, 3.0eq of 1-hydroxybenzotriazole and 10eq of N, N-diisopropylethylamine into the resin, reacting at room temperature for 1.5-2.5 h, deprotecting, finally adding excision liquid trifluoroacetic acid/phenol/triisopropylsilane/water, reacting at room temperature for 2.5-3.5 h, collecting reaction liquid, and concentrating under reduced pressure to obtain a crude product.

4. The process of claim 3, wherein the crude product is obtained followed by a purification step comprising: purifying by reversed phase high performance liquid chromatography, and freeze drying to obtain pure product.

5. The method according to claim 3, wherein the volume ratio of the cutting solution trifluoroacetic acid/phenol/triisopropylsilane/water is 88:5:5: 2.

6. The use of a compound according to claim 1 or 2 which promotes targeted degradation of the TGF- β 1 protein in the treatment of tumours.

7. Use of a compound according to claim 1 or claim 2 which promotes targeted degradation of the TGF- β 1 protein in the treatment of a tissue fibrotic disease.

8. Use of a compound according to claim 1 or claim 2 which promotes targeted degradation of the TGF- β 1 protein in the treatment of skin scarring.