Process for the preparation of end-functionalized degradable polymers in one step and applications

Abstract

The application discloses a method for preparing a terminal functional degradable polymer in one step, and the method comprises the following steps: under an inert atmosphere, carrying out a polyester reaction on a borane, an alpha-amine group omega-hydroxyl initiator, a catalyst and a cyclic lactone in an organic solvent to prepare a terminal amine group degradable polymer. The application utilizes the characteristics of N-B interaction between the borane and the amine group to protect the amine group, realizes one-step preparation of the alpha-amine group omega-hydroxyl degradable aliphatic polymer, does not need to carry out complicated protection and deprotection steps like traditional methods, reduces solvent use, is green and environment-friendly, is low in cost, is mild in reaction condition, is high in production efficiency and is simple in post-treatment.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer synthesis, and more specifically, relates to a method and application for preparing terminal functionalized degradable polymers based on BN non-covalent interaction. Background Art

[0002] Aliphatic polyesters are highly favored due to their outstanding properties, such as biocompatibility and biodegradability. Typically, the primary method for synthesizing aliphatic polyesters is ring-opening polymerization (ROP). Amine-terminated polymers have a wide range of applications in the biopharmaceutical field, where their terminal amine groups can be used to link polymers to bioactive molecules. In the conventional organocatalytic synthesis of amine-terminated degradable polymers, α-terminated amine and ω-terminated hydroxyl initiators are typically used to introduce amine groups. However, because amine groups can initiate polymerization of cyclic monomers and result in greater dispersibility, a series of complex protection and deprotection procedures are often required for the terminal amine groups of the initiator, typically using Cbz or Boc groups. This protection and deprotection process consumes large amounts of organic solvents. Therefore, the development of a simple terminal amine protection system is of great significance. Summary of the Invention

[0003] In order to address the above-mentioned deficiencies and shortcomings of the prior art, the primary purpose of the present invention is to provide a method for preparing a degradable polymer based on BN non-covalent interaction.

[0004] The present invention has discovered that borane can complex with amine groups, protecting them through complexation. The borane-amine complex is suitable for the ring-opening polymerization reaction environment of cyclic aliphatic polyesters, and deprotection can be completed in diethyl ether. Through the non-covalent interaction between borane and amine groups, the complex can be synthesized in a single step during the synthesis of amino-terminated aliphatic polyesters without the complicated protection and deprotection steps.

[0005] The technical solution adopted in the present invention is as follows:

[0006] A one-step method for preparing a terminal functionalized degradable polymer, comprising:

[0007] Under an inert atmosphere, borane, an α-terminal amino group and an ω-terminal hydroxyl group initiator, a catalyst, and a cyclic lactone are reacted in an organic solvent to produce a polyester to obtain a terminal amino group degradable polymer, namely the terminal functionalized degradable polymer.

[0008] The α-terminated amino group and ω-terminated hydroxyl group initiator is one or more of ethanolamine, hexanolamine, 4-aminobenzyl alcohol, diethanolamine, and triethanolamine.

[0009] The borane is one or more of triethylboron, tributylboron, triphenylboron, triisopropylacetonate borane and tris(pentafluorophenyl)borane.

[0010] The cyclic lactone is one or more of lactide, caprolactone, valerolactone or trimethylene carbonate. The lactide is preferably L-lactide.

[0011] The molar ratio of the borane, the amino group in the α-terminated amino group and ω-terminated hydroxyl group initiator, and the cyclic lactone is (0.1-1.5): (0.1-1.0): (20-100).

[0012] The molar ratio of borane to the amino group in the α-terminated amino group and ω-terminated hydroxyl group initiator is preferably 1 to 1.5:1, more preferably 1.2 to 1.3:1.

[0013] The molar ratio of the cyclic lactone to the amino group in the α-terminated amino group and ω-terminated hydroxyl group initiator is preferably 20 to 80:1.

[0014] In the method of the present invention, the catalyst is one or more of DBU and t-Bu-P2 catalyst, preferably DBU catalyst. The molar ratio of the catalyst to the cyclic lactone is 1:20-50.

[0015] In the present invention, the organic solvent is generally one or more of dichloromethane, tetrahydrofuran, dioxane, and toluene.

[0016] The volume usage of the organic solvent is generally 0.1 to 10 mL / mmol based on the amount of the cyclic lactone.

[0017] The temperature of the polyester reaction is 25-75° C., preferably at room temperature.

[0018] The polyester reaction time is 0.5-6 hours, preferably 2-6 hours.

[0019] Furthermore, it is preferred that the method is carried out according to the following steps:

[0020] Under an inert atmosphere, borane, an α-terminal amino group and ω-terminal hydroxyl group initiator, and a catalyst are dissolved in an organic solvent to obtain a premixed solution; after the cyclic lactone is dissolved in the organic solvent, the premixed solution is added and a polyester reaction is carried out at room temperature to prepare a terminal amino group degradable polymer.

[0021] After the polyester reaction is completed, the reaction solution is post-treated to produce a terminal amine-group degradable polymer. The post-treatment method generally comprises the following steps: adding the resulting reaction product to a mixed solution of glacial methanol and diethyl ether to obtain a precipitate, filtering the precipitate, and vacuum drying the precipitate to produce the terminal amine-group degradable polymer. The volume ratio of glacial methanol to diethyl ether is preferably 1:1.

[0022] The inert atmosphere is generally nitrogen or argon.

[0023] The present invention also provides a terminal amino-degradable polymer prepared by the above method.

[0024] The present invention also provides applications of the terminal amine-degradable polymer in the biomedical field. Common applications include: using the terminal amine-degradable polymer as a reaction site to react with N-carboxyl cyclic anhydride to prepare a block copolymer that can be used for drug delivery.

[0025] The present invention utilizes NB non-covalent interaction to protect amino groups and directly prepare terminal functionalized degradable polymers. In the method, when the borane is triethylborane and the α-terminal amino group and ω-terminal hydroxyl group initiator is ethanolamine, the specific reaction process is shown in the following chemical formula:

[0026]

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] (1) The present invention only requires a one-step process to prepare terminal amino aliphatic polyesters, and does not require complicated protection and deprotection steps like traditional methods, thereby reducing the use of solvents, being environmentally friendly, and having low cost.

[0029] (2) The reaction of the present invention can be carried out at room temperature, and the reaction conditions are mild.

[0030] (3) Short reaction time, high production efficiency, and simple post-processing.

[0031] (4) In the post-treatment step, if diethyl ether is not added to remove triethyl boron, the complexation between the terminal amine group and triethyl boron can continue to protect the amine group. When triethyl boron needs to be removed, diethyl ether is simply added. The method for removing triethyl boron is simple and efficient. DETAILED DESCRIPTION

[0032] The present invention will be further described below in conjunction with specific examples, but should not be construed as limiting the present invention. Unless otherwise specified, the technical means used in the examples are conventional means well known to those skilled in the art. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0033] Example 1

[0034] Under the protection of high-purity argon, dichloromethane (DCM) (0.5 ml), ethanolamine (EA) (0.1 mmol, 5.5 μl, 1 eq), triethylboron (Et3B) (0.12 mmol, 120 μl, 1.2 eq) ([1 M] THF solution), and DBU (0.1 mmol, 14 μl) were pre-mixed. Monomer lactide (LA) (288 mg, 2 mmol) was added to a 10 ml Schlenk bottle. DCM (0.5 ml) was then added to dissolve the monomer. The pre-mixed solution was then added and reacted at room temperature for 2 h. After the polymerization reaction was completed, a sample was taken and the LA monomer conversion rate was 97.6% by nuclear magnetic resonance analysis. The remaining reaction mixture was precipitated with an excess of icy methanol / ether solution (volume ratio 1:1), filtered, and vacuum dried to obtain the polymerization product, polylactide (PLA) (M n =4800g / mol, ).

[0035] 1 H NMR (400MHz, DMSO): δ (ppm) 1.47 (3H,-CH-CH3-), 1.76 (2H, NH2-CH2-CH2-O-), 3.60 (2H, NH2-CH2-CH2-O-), 5.20 (1H, -CH-CH3).

[0036] Example 2

[0037] The difference from Example 1 is that ethanolamine was replaced with hexanolamine. After the reaction was completed, samples were taken and the conversion rate of LA monomer was calculated by nuclear magnetic resonance and was 96.8%. The obtained polymerization product was polylactide (M n =5000g / mol, ).

[0038] Example 3

[0039] The difference from Example 1 is that ethanolamine was replaced with 4-aminobenzyl alcohol. After the reaction, samples were taken and the conversion rate of LA monomer was calculated by NMR to be 93.8%. The obtained polymerization product was polylactide (M n =5400 g / mol, D=1.14).

[0040] Example 4

[0041] The difference from Example 1 is that ethanolamine was replaced with diethanolamine, and the molar ratio of LA: amine group: borane was maintained at 20:1:1.2. After the reaction was completed, samples were taken and the conversion rate of LA monomer was calculated by NMR to be 90.4%. The obtained polymerization product was polylactide (M n =8300g / mol, ).

[0042] Example 5

[0043] The difference from Example 1 is that ethanolamine was replaced with triethanolamine, and the molar ratio of LA: amine group: borane was maintained at 20:1:1.2. After the reaction was completed, samples were taken and the conversion rate of LA monomer was calculated by nuclear magnetic resonance to be 89.4%, which is lower than the catalytic efficiency of ethanolamine. The obtained polymerization product is polylactide (M n =13600 g / mol, ).

[0044] Different initiators were used to prepare terminal amino polylactide, and the obtained data are shown in Table 1 below.

[0045] Table 1

[0046]

[0047] Example 6

[0048] The difference from Example 1 is that triethylboron was replaced with tributylboron. After the reaction, samples were taken and the conversion rate of LA monomer was calculated by NMR to be 94.8%. The obtained polymerization product was polylactide (M n =4800g / mol, ).

[0049] Example 7

[0050] The difference from Example 1 is that triethylboron was replaced with triphenylboron. After the reaction was completed, samples were taken and the conversion rate of LA monomer was calculated by nuclear magnetic resonance and was 89.4%. The obtained polymerization product was poly (hexamethylenetetracycline) (M n =3900 g / mol, ).

[0051] Example 8

[0052] The difference from Example 1 is that triethylborane was replaced with triisopropylacetonato borane. After the reaction, samples were taken and the conversion rate of LA monomer was calculated by NMR to be 84.9%. The obtained polymerization product was polylactide (M n =3600g / mol, ).

[0053] Example 9

[0054] The difference from Example 1 is that triethylborane was replaced with tri(pentafluorophenyl)borane. After the reaction, samples were taken and the conversion rate of LA monomer was calculated by NMR to be 83.8%. The obtained polymerization product was polylactide (M n =3400 g / mol, ).

[0055] Amine-terminated polylactide was prepared using different boranes at different temperatures, and the obtained data are shown in Table 2 below.

[0056] Table 2

[0057]

[0058] From the data analysis of Example 1, Examples 6-9 and Table 2, it can be seen that as the steric hindrance of borane increases, the interaction between N-B decreases, which can lead to the deprotection of amino groups. The polymerization of monomers initiated by amino groups can lead to a larger dispersity.

[0059] Example 10

[0060] In this example, the difference from Example 1 is that the reaction temperature is changed from 25°C to 35°C, and the other conditions are the same as in Example 1. After the polymerization reaction is completed, sampling is performed, and nuclear magnetic resonance analysis shows that the conversion rate of lactide (LA) monomers is 98.2%.

[0061] Example 11

[0062] In this example, the difference from Example 1 is that the reaction temperature is changed from 25°C to 45°C, and the other conditions are the same as in Example 1. After the polymerization reaction is completed, sampling is performed, and nuclear magnetic resonance analysis shows that the conversion rate of lactide (LA) monomers is 98.8%.

[0063] Example 12

[0064] In this example, the difference from Example 1 is that the reaction temperature is changed from 25°C to 55°C, and the other conditions are the same as in Example 1. After the polymerization reaction is completed, sampling is performed, and nuclear magnetic resonance analysis shows that the conversion rate of lactide (LA) monomers is 99.5%.

[0065] Example 13

[0066] In this example, the difference from Example 1 is that the reaction temperature is changed from 25°C to 65°C, and the other conditions are the same as in Example 1. After the polymerization reaction is completed, sampling is performed, and nuclear magnetic resonance analysis shows that the conversion rate of lactide (LA) monomers is 99.9%.

[0067] Example 14

[0068] In this example, the difference from Example 1 is that the reaction temperature is changed from 25°C to 75°C, and the other conditions are the same as in Example 1. After the polymerization reaction is completed, sampling is performed, and nuclear magnetic resonance analysis shows that the conversion rate of lactide (LA) monomers is 99.9%.

[0069] Amine-terminated poly-lactide is prepared at different temperatures using N-B interaction, and the data obtained are shown in Table 3.

[0070] Table 3

[0071]

[0072] Analysis of the data in Examples 1, 10-14, and Table 3 indicates that reaction temperature has little effect on the ring-opening polymerization of lactide. At 25°C, the conversion of lactide (LA) monomer is already high, reaching 97.6%. Increasing the temperature can increase the conversion to 99.9%, but this also slightly increases the dispersion, resulting in an unsatisfactory effect. Therefore, a reaction temperature of 25°C is selected to conserve energy and achieve a more efficient reaction.

[0073] Example 15

[0074] This embodiment differs from embodiment 1 in that the reaction time is changed from 2 hours to 0.5 hours, and the rest is the same as embodiment 1. After the polymerization reaction, samples were taken and analyzed by nuclear magnetic resonance, and the conversion rate of lactide (LA) monomer was 10.1%.

[0075] Example 16

[0076] This embodiment differs from Embodiment 1 in that the reaction time is changed from 2 hours to 1 hour, and the rest is the same as Embodiment 1. After the polymerization reaction, samples were taken and analyzed by nuclear magnetic resonance, and the conversion rate of lactide (LA) monomer was 34.4%.

[0077] Example 17

[0078] This embodiment differs from embodiment 1 in that the reaction time is changed from 2 hours to 1.5 hours, and the rest is the same as embodiment 1. After the polymerization reaction, samples were taken and analyzed by nuclear magnetic resonance, and the conversion rate of lactide (LA) monomer was 88.2%.

[0079] Example 18

[0080] This embodiment differs from embodiment 1 in that the reaction time is changed from 2 hours to 2.5 hours, and the rest is the same as embodiment 1. After the polymerization reaction, samples were taken and analyzed by nuclear magnetic resonance, and the conversion rate of lactide (LA) monomer was 98.5%.

[0081] Example 19

[0082] This embodiment differs from embodiment 1 in that the reaction time is changed from 2 hours to 3 hours, and the rest is the same as embodiment 1. After the polymerization reaction, samples were taken and analyzed by nuclear magnetic resonance, and the conversion rate of lactide (LA) monomer was 99.1%.

[0083] Example 20

[0084] This embodiment differs from embodiment 1 in that the reaction time is changed from 2 hours to 4 hours, and the rest is the same as embodiment 1. After the polymerization reaction, samples were taken and analyzed by nuclear magnetic resonance, and the conversion rate of lactide (LA) monomer was 99.5%.

[0085] Example 21

[0086] This embodiment differs from embodiment 1 in that the reaction time is changed from 2 hours to 5 hours, and the rest is the same as embodiment 1. After the polymerization reaction, samples were taken and analyzed by nuclear magnetic resonance, and the conversion rate of lactide (LA) monomer was 99.7%.

[0087] Example 22

[0088] This embodiment differs from embodiment 1 in that the reaction time is changed from 2 hours to 6 hours, and the rest is the same as embodiment 1. After the polymerization reaction, samples were taken and analyzed by nuclear magnetic resonance, and the conversion rate of lactide (LA) monomer was 99.9%.

[0089] Amine-terminated polylactide was prepared using NB interaction at different reaction times, and the obtained data are shown in Table 4 below.

[0090] Table 4

[0091]

[0092] Analysis of the data in Examples 1, 15-22, and Table 4 demonstrates that reaction time significantly influences the conversion of lactide (LA) monomer. At a lactide (LA) to ethanolamine molar ratio of 20:1, the polymerization rate significantly increased after one hour of reaction. By the sixth hour, the lactide (LA) monomer was essentially completely ring-opened, achieving a monomer conversion of 99.9%.

[0093] Example 23

[0094] This example differed from Example 1 in that the molar ratio of lactide (LA) monomer to ethanolamine was changed from 20:1 to 30:1, and the reaction time was changed from 2 hours to 6 hours. All other aspects were the same as in Example 1. After the polymerization reaction, samples were collected, and nuclear magnetic resonance analysis revealed a lactide (LA) monomer conversion rate of 99.9%.

[0095] Example 24

[0096] This example differed from Example 1 in that the molar ratio of lactide (LA) monomer to ethanolamine was changed from 20:1 to 50:1, and the reaction time was changed from 2 hours to 6 hours. All other aspects were the same as in Example 1. After the polymerization reaction, samples were collected, and nuclear magnetic resonance analysis revealed a lactide (LA) monomer conversion rate of 99.9%.

[0097] Example 25

[0098] This example differed from Example 1 in that the molar ratio of lactide (LA) monomer to ethanolamine was changed from 20:1 to 80:1, and the reaction time was changed from 2 hours to 6 hours. All other aspects were the same as in Example 1. After the polymerization reaction, samples were collected, and nuclear magnetic resonance analysis revealed a lactide (LA) monomer conversion rate of 99.5%.

[0099] Example 26

[0100] This example differs from Example 1 in that the molar ratio of lactide (LA) monomer to ethanolamine is changed from 20:1 to 100:1, and the reaction time is changed from 2 hours to 6 hours. All other reactions are identical to those in Example 1. After the polymerization reaction, samples were collected, and nuclear magnetic resonance analysis revealed a lactide (LA) monomer conversion rate of 95.7%.

[0101] Example 27

[0102] This example differs from Example 1 in that the molar ratio of lactide (LA) monomer to ethanolamine is changed from 20:1 to 200:1, and the reaction time is changed from 2 hours to 6 hours. All other reactions are identical to those in Example 1. After the polymerization reaction, samples were collected, and nuclear magnetic resonance analysis revealed a lactide (LA) monomer conversion rate of 83.9%.

[0103] Example 28

[0104] This example differed from Example 1 in that the molar ratio of lactide (LA) monomer to ethanolamine was changed from 20:1 to 500:1, and the reaction time was changed from 2 hours to 6 hours. All other reactions were identical to Example 1. After the polymerization reaction, samples were collected, and nuclear magnetic resonance analysis revealed a lactide (LA) monomer conversion rate of 53.3%.

[0105] Example 29

[0106] This example differed from Example 1 in that the molar ratio of lactide (LA) monomer to ethanolamine was changed from 20:1 to 1000:1, and the reaction time was changed from 2 hours to 6 hours. All other reactions were identical to those in Example 1. After the polymerization reaction, samples were collected, and nuclear magnetic resonance analysis revealed a lactide (LA) monomer conversion rate of 33.9%.

[0107] Example 30

[0108] This embodiment differs from Embodiment 29 in that the reaction time is changed from 6 hours to 8 hours, and the rest is the same as Embodiment 29. After the polymerization reaction, samples were taken and analyzed by nuclear magnetic resonance, and the conversion rate of lactide (LA) monomer was 45.7%.

[0109] Example 31

[0110] This embodiment differs from Embodiment 29 in that the reaction time is changed from 6 hours to 12 hours, and the other aspects are the same as Embodiment 29. After the polymerization reaction, samples were taken and analyzed by nuclear magnetic resonance, and the conversion rate of lactide (LA) monomer was 60.1%.

[0111] Example 32

[0112] This embodiment differs from Embodiment 29 in that the reaction time is changed from 6 hours to 18 hours, and the other aspects are the same as Embodiment 29. After the polymerization reaction, samples were taken and analyzed by nuclear magnetic resonance, and the conversion rate of lactide (LA) monomer was 82.2%.

[0113] Example 33

[0114] This embodiment differs from Embodiment 29 in that the reaction time is changed from 6 hours to 24 hours, and the other aspects are the same as Embodiment 29. After the polymerization reaction, samples were taken and analyzed by nuclear magnetic resonance, and the conversion rate of lactide (LA) monomer was 83.9%.

[0115] The amino-terminated polylactide was prepared by NB interaction at different molar ratios of lactide (LA) monomer to ethanolamine, and the obtained data are shown in Table 5 below.

[0116] Table 5

[0117]

[0118]

[0119] Analysis of the data in Examples 23-33 and Table 5 indicates that when the molar ratio of lactide (LA) monomer to ethanolamine exceeds 200 and the reaction is continued for 6 hours (as in Examples 28-29), the conversion rate of lactide (LA) monomer decreases significantly, requiring a longer reaction time. When the molar ratio of lactide (LA) monomer to ethanolamine is 1000:1 (as in Examples 29-33), the conversion rate of lactide (LA) monomer does not continue to increase even after a 24-hour reaction.

[0120] Example 34

[0121] This example differs from Example 1 in that the monomer used was changed from lactide (288 mg, 2 mmol) to valerolactone (200 mg, 2 mmol), and the other reactions were the same as in Example 1. After the polymerization, samples were taken and analyzed by nuclear magnetic resonance (NMR), revealing a conversion rate of valerolactone of 99.9%.

[0122] Example 35

[0123] This embodiment differs from embodiment 1 in that the monomer used is changed from lactide (288 mg, 2 mmol) to caprolactone (228 mg, 2 mmol), and the other reactions are the same as those in embodiment 1. After the polymerization reaction, samples were taken and analyzed by nuclear magnetic resonance (NMR) to determine that the conversion rate of the valerolactone monomer was 78.9%.

[0124] Example 36

[0125] This example differs from Example 1 in that the monomer used was changed from lactide (288 mg, 2 mmol) to trimethylene carbonate (204 mg, 2 mmol), and the other reactions were the same as in Example 1. After the polymerization, samples were taken and analyzed by nuclear magnetic resonance (NMR) to determine that the conversion rate of the valerolactone monomer was 95.2%.

[0126] Under different monomer conditions, terminal amino polyester-based degradable polymers were prepared using NB interaction, and the obtained data are shown in Table 6 below.

[0127] Table 6

[0128]

[0129] Through the analysis of the data in Example 1, Examples 34 to 36 and Table 6, it can be seen that the above experimental results show that ethanolamine with amine groups protected by NB interaction can also effectively prepare ring-opening polymers of valerolactone, lactide and trimethylene carbonate with amino terminals to obtain the corresponding α-terminated amino group and ω-terminated hydroxyl polymers.

[0130] Example 37

[0131] The difference from Example 1 is that DBU was replaced with t-Bu-P2. After the reaction, samples were taken and the conversion rate of LA monomer was calculated by NMR to be 44.9%. The obtained polymerization product was polylactide (M n =2000g / mol, ).

[0132] Example 38

[0133] In this embodiment, the difference from Example 37 is that the reaction time is changed from 2 hours to 24 hours, and the other aspects are the same as in Example 37. After the reaction, a sample is taken and the conversion rate of LA monomer is calculated by NMR to be 62.4%. The obtained polymerization product is polylactide (M n =2500g / mol, ).

[0134] It can be seen from Examples 37 and 38 that t-Bu-P2 is less effective as a catalyst for the preparation of polycaprolactone by protecting the terminal amine groups through NB interaction. This may be because PB coordination occurs, resulting in the occupation of the active sites of the catalyst, a decrease in catalytic efficiency, and the occupation of the NB complexation sites, causing the deprotection of the amine groups, resulting in an increase in the molecular weight distribution.

[0135] Therefore, the present invention preferably uses DBU as the catalyst.

[0136] The above embodiments are preferred implementations of the present invention, but the implementations of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A one-step method for preparing a terminal functionalized degradable polymer, characterized in that: The method is: Under an inert atmosphere, borane, an α-terminal amino group and ω-terminal hydroxyl group initiator, a catalyst, and a cyclic lactone are reacted in an organic solvent to produce a terminal amino group degradable polymer. The molar ratio of the borane, the amino group in the α-terminal amino group and ω-terminal hydroxyl group initiator, and the cyclic lactone is (0.1-1.5):(0.1-1.0):(30-100); and the molar ratio of the catalyst to the cyclic lactone is 1:20-50.

2. The method according to claim 1, wherein The α-terminated amino group and ω-terminated hydroxyl group initiator is one or more of ethanolamine, hexanolamine, 4-aminobenzyl alcohol, diethanolamine, and triethanolamine.

3. The method according to claim 1, wherein The borane is one or more of triethylboron, tributylboron, triphenylboron, triisopropylacetonate borane and tris(pentafluorophenyl)borane.

4. The method according to claim 1, wherein The cyclic lactone is one or more of L-lactide, caprolactone, valerolactone or trimethylene carbonate.

5. The method according to claim 1, wherein The temperature of the polyester reaction is 25-75°C.

6. The method according to claim 1, wherein The catalyst is DBU, t -One or more of Bu-P2.

7. The method according to claim 1, wherein After the polyester reaction is completed, the reaction solution is post-treated to obtain a terminal amino-degradable polymer. The post-treatment method is as follows: after the reaction is completed, the obtained reaction product is added to a mixed solution of icy methanol and ether to obtain a precipitate, which is then filtered and vacuum-dried to obtain the terminal amino-degradable polymer.

8. The terminal amine-group degradable polymer prepared by the method according to any one of claims 1 to 7.

9. Use of the terminal amine-degradable polymer according to claim 8 in the biomedical field.

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