A method for preparing high-purity monodisperse polyethylene glycol derivatives

Abstract

The present invention discloses a method for preparing high-purity monodisperse polyethylene glycol derivatives. This method uses monodisperse oligoethylene glycol derivatives and vinyl sulfate or substituted vinyl sulfate as raw materials, and prepares high-purity long-chain monodisperse polyethylene glycol derivatives through click chain growth under mild conditions, providing high-quality modifiers for the polyethylene glycol modification of biomedicines. The advantages of the method of the present invention are as follows: 1) The raw materials used, oligoethylene glycol derivatives and vinyl sulfate, are cheap and easily available and non-toxic; 2) The reaction conditions are mild, the reaction speed is fast, and the homolog impurities can be effectively controlled; 3) The product does not need to be purified by column chromatography, is easy to scale up for preparation, the obtained product has a purity greater than 99%, and the single impurity is less than 0.5%. The method of the present invention has significant advantages such as simple process, low cost, high yield, and high purity, is suitable for large-scale preparation of high-purity monodisperse polyethylene glycol derivatives for medicinal use, and has good industrial application prospects and economic and social value.

Description

Technical Field

[0001] The present invention belongs to the technical fields of fine organic synthesis and polyethylene glycol modified biomedicine, and particularly relates to an efficient preparation method of high-purity monodisperse polyethylene glycol derivatives. Background Art

[0002] Polyethylene glycol (PEG) has excellent water solubility and biocompatibility, and has developed into the preferred polymer for covalently modifying the surfaces of bioactive molecules, liposomes, and lipid nanoparticles, etc. The application fields of polyethylene glycol modification are extensive, mainly involving six major fields such as the creation of biomedicines such as polypeptides and proteins, the preparation of drug delivery carriers such as liposomes and nanoparticles, the linkers of antibody-drug conjugates and proteolysis-targeting chimeras, the creation of fluorescent labels and diagnostic reagents, the modification of oligonucleotides, and the modification of material surfaces. By covalently modifying polypeptides and proteins with polyethylene glycol to form an "invisible coat" on their surfaces, the half-life of the original drug can be significantly extended, and the pharmacokinetics and efficacy can be improved. It has developed into an indispensable golden technology for modifying biomedicines. For example, polyethylene glycol recombinant human growth hormone injection (Jinsai Zeng), polyethylene glycol interferon, semaglutide, tirzepatide, etc. Goldman Sachs expects the market size of PEGylated drugs and drug delivery carriers to reach $100 billion in 2030.

[0003] Polyethylene glycol can be divided into two major categories according to its molecular composition, namely polydisperse polyethylene glycol with mixture characteristics and monodisperse polyethylene glycol with pure substance characteristics. Using polydisperse polyethylene glycol to covalently modify biomedicines, its mixture characteristics result in complex drug-forming components and irregular surface structures of the modified proteins and lipid nanoparticles, increasing the non-specific binding sites in vivo of protein drugs, liposomes or nanoparticles, leading to a large range of anti-polyethylene glycol antibodies being produced, and the safety risks are becoming increasingly prominent. Over the past 30 years, anti-polyethylene glycol antibodies have increased by 360 times. High-purity monodisperse polyethylene glycol is not only an ideal choice for modifying active molecules, but also an effective way to relieve the pain points of the anti-polyethylene glycol antibody industry. However, high-purity monodisperse polyethylene glycol is difficult to prepare on a large scale, and its high price severely restricts its widespread use in the biomedical field.

[0004] The Williamson ether synthesis method is a commonly used method for synthesizing the main chain of monodisperse polyethylene glycol. Under strong base and heating conditions, the monodisperse polyethylene glycol raw material forms a polyethylene glycol sodium salt intermediate, which then reacts with an electrophilic reagent to obtain a chain growth product. At the same time, this sodium salt intermediate will undergo intramolecular cleavage to generate a sodium salt with one less ethylene glycol unit, and the latter participates in competitive chain growth to obtain a homolog impurity with one less ethylene glycol unit. Their properties are similar, making it very difficult to remove by-products and difficult to obtain high-purity products. This is a huge challenge faced in the preparation of high-purity monodisperse polyethylene glycol.

[0005]

[0006] The methods for synthesizing monodisperse polyethylene glycol reported in existing literature or patents all require heating, and chain breakage is difficult to avoid. The starting materials are mainly divided into two categories: one is synthesized from chain-like sulfonic acid esters as raw materials; the other is synthesized based on macrocyclic sulfate esters as raw materials. Both synthesis schemes require the purification of products by column chromatography, and the separation cost is high. Even with high separation costs, the product purity is still difficult to meet the pharmaceutical requirements of greater than 99% and a single impurity of homologues less than 0.5%. The representative literature is as follows:

[0007] 1) In 2004, Hill et al. (J. Org. Chem. 2004, 69, 639 - 647.) reported a method for synthesizing asymmetric monodisperse polyethylene glycol derivatives. This method extends the PEG chain through a chain growth - selective deprotection - iterative chain growth progressive mode, and prepared PEG 6 、PEG 9 、PEG 12 、PEG 15 、PEG 18 and PEG 24 and a series of monodisperse polyethylene glycols with different chain lengths, and the yields were between 60% and 98%.

[0008]

[0009] 2) In 2006, Tanaka et al. (J. Org. Chem. 2006, 71, 9884 - 9886.) reported a method for synthesizing glycol. Two molecules of compound 4 and one molecule of tetraethylene glycol underwent two Williamson ether syntheses to obtain dibenzyl-protected dodecaglycol with a yield of 73%. After deprotection, dodecaglycol was obtained with a yield of 97%. Iterating three times gave 36-glycol 5. Two molecules of compound 4 reacted with one molecule of 5 to obtain dibenzyl-protected 44-glycol 6. After debenzylation protection, 44-glycol 7 was obtained with a two-step yield of 67.6%.

[0010]

[0011] 3) In 2008, Springer et al. (Bioconjug. Chem. 2008, 19, 973 - 981.) synthesized nonacosaglycol using a method similar to that reported by Tanaka et al. Hexaglycol reacted with benzyl bromide to obtain monobenzyl-protected compound 8. Using NaH as the base, compound 8 and p-toluenesulfonate 9 derived from pentaglycol were refluxed in tetrahydrofuran for 24 hours to obtain the chain growth product 10. Compound 10 was debenzylated to obtain 17-glycol 11. After a similar process, nonacosaglycol 12 was finally obtained. Springer et al. found that such long-chain glycols can precipitate in a dichloromethane - cold ether mixed solvent system.

[0012]

[0013] 4) In 2009, Davis et al. (Angew. Chem. Int. Ed. 2009, 48, 1248 - 1252.) made adjustments and designs in the feeding method and sequence to reduce the generation of chain cleavage by-products. First, the raw materials were dissolved in DMF, and then NaH or potassium tert-butoxide was slowly added to reduce the real-time concentration of the base in the system, thereby inhibiting chain cleavage. This scheme used cheap and readily available high-purity tetraethylene glycol as the starting material, and through single-end benzyl protection - sulfonation - single-end chain amplification, repeating iteratively, triacontadiol and octatetracontadiol were obtained with purities of 98.9% and 98.0% respectively. Davis et al. inhibited the cleavage of the PEG chain to a certain extent by changing the feeding sequence, but could not completely avoid it.

[0014]

[0015] 5) In 2015, Jiang Zhongxing et al. (Angew. Chem. Int. Ed. 2015, 54, 3763 - 3767.) developed a new strategy for the efficient synthesis of monodisperse polyethylene glycol using glycol-based macrocyclic sulfate as the raw material. This strategy could use the sulfonate twice, avoiding the protection and activation of hydroxyl groups and improving the efficiency of synthesizing long-chain glycols. Taking the synthesis of monomethyl ether series products as an example, sodium methoxide was used to nucleophilically ring-open compound 15 to obtain octaethylene glycol monomethyl ether 16. Compound 16 then reacted with macrocyclic sulfate 15, repeating 7 times, and hexatetracontadiol monomethyl ether 17 was obtained with an overall yield of 15%. This method significantly improved the efficiency of chain growth, but the synthesis cost of macrocyclic sulfate was relatively high, and it was also difficult to avoid the cleavage problem.

[0016] Summary of the Invention

[0017] The object of the present invention is to provide a method for preparing high-purity monodisperse polyethylene glycol derivatives for medicinal use with simple process, low price, high product purity, mild conditions and good yield to meet the urgent needs of the polyethylene glycol modification in the biomedical industry.

[0018] For the above object, the present invention uses monodisperse oligoethylene glycol R 1 -PEG n -OH (n≥2) and vinyl sulfate or substituted vinyl sulfate as raw materials, and efficiently prepares a high-purity monodisperse polyethylene glycol main chain R 1 -PEG n+1 -OH with one more ethylene glycol unit under the conditions of corresponding base, solvent, temperature and reaction time; and R 1 -PEG n+1-OH can be used to perform multiple iterative reactions in the same method to prepare long-chain monodisperse polyethylene glycol derivatives with more ethylene glycol units. The specific method includes the following steps:

[0019] Step 1: React the monodisperse oligomeric polyethylene glycol derivative R 1 -PEG n -OH and vinyl sulfate or substituted vinyl sulfate in the presence of a base in a solvent to undergo a nucleophilic substitution reaction to obtain a sulfonate intermediate; after extraction of the sulfonate intermediate, it is hydrolyzed by refluxing with concentrated sulfuric acid in tetrahydrofuran to obtain a high-purity chain growth product R 1 -PEG n+1 -OH with one more ethylene glycol unit; the reaction formula is as follows:

[0020]

[0021] In the formula, R 1 represents any one of -N 3 , -Cl, C 1 ~C 4 alkoxy, aryloxy, amide, sulfonamide, C 2 ~C 4 alkynyloxy, C 2 ~C 4 alkenyloxy; n is an integer ≥ 2; R represents -H, -F, -Cl, -CH 3 , -CH 2 CH 3 , -Bn, -Ph, -CH 2 Cl, -CH 2 OBn, -CH 2 OTBS, -CH 2 N 3 , -CH 2 NBn 2 any one of them.

[0022] Step 2: Perform multiple iterative reactions on the chain growth product according to the method of Step 1 to obtain a long-chain high-purity monodisperse polyethylene glycol derivative with more ethylene glycol units.

[0023] In the above Step 1, R 1 further represents any one of alkoxy such as -N 3 , -Cl, -OCH 3 , -OtBu, aryloxy such as -OBn, -OPh, amide such as -NHBoc, -NHCbz, -NHCOPh, sulfonamide such as -NHTs, alkynyloxy such as -OCH 2 C≡CH, alkenyloxy such as -OCH 2 CH=CH 2 any one of them.

[0024] In the above step 1, the structures of ethylene sulfate and substituted ethylene sulfate are as follows:

[0025]

[0026] In the above step 1, it is preferred that the molar ratio of the monodisperse oligoethylene glycol R 1 -PEG n -OH to ethylene sulfate or substituted ethylene sulfate and base is 1:1.2 - 2.0:1.2 - 1.5.

[0027] In the above step 1, it is preferred that the base is any one of NaOH, KOH, NaH, NaOtBu, and KOtBu.

[0028] In the above step 1, it is preferred that the solvent is any one of tetrahydrofuran, ethylene glycol dimethyl ether, dioxane, N,N-dimethylformamide, and dichloromethane.

[0029] In the above step 1, it is preferred that the temperature of the nucleophilic substitution reaction is -20 to 20 °C.

[0030] In the above step 1, it is preferred that the time of the nucleophilic substitution reaction is 1 to 2 hours.

[0031] In the above step 1, it is preferred that the molar ratio of the monodisperse oligoethylene glycol R 1 -PEG n -OH to concentrated sulfuric acid is 1:0.2 - 1.2.

[0032] In the above step 1, it is preferred that the time of hydrolysis under reflux is 2 to 4 hours.

[0033] In the above step 2, during the iterative reaction process, the monodisperse polyethylene glycol main chain is stable, and related single impurities can be effectively controlled. During the iterative reaction process, ethylene sulfate and substituted ethylene sulfate can also be alternately used to prepare monodisperse polyethylene glycol main chains with diverse structures to meet different functions.

[0034] The beneficial effects of the present invention are as follows:

[0035] 1. The present invention uses ethylene sulfate and its derivatives with ring strain as raw materials to achieve the chain growth of polyethylene glycol under mild conditions, providing a new route for the large-scale preparation of high-purity monodisperse polyethylene glycol derivatives for medicinal use at low cost.

[0036] 2. The starting material oligoethylene glycol derivative R used in the present invention 1 -PEG n-OH (n≤4) and vinylene sulfate (DTD), etc. are all commercially available and inexpensive raw materials. Through iterative chain growth reactions, high-purity products of various lengths can be efficiently prepared; during the iterative reaction process, vinylene sulfate and substituted vinylene sulfate can be alternately used to prepare monodisperse polyethylene glycol main chains with diverse structures and meeting different functions.

[0037] 3. The preparation method of the present invention can effectively control the side reaction of chain cleavage, and monodisperse polyethylene glycol derivatives with a purity greater than 99% and a single impurity content of related homologues less than 0.5% can be obtained without column chromatography purification. Description of the Drawings

[0038] Figure 1 is the GC chromatogram of MPEG 5 -OH.

[0039] Figure 2 is the 5 HNMR (400 MHz, CDCl 1 ) chromatogram of MPEG 3 -OH.

[0040] Figure 3 is the GC chromatogram of MPEG 6 -OH.

[0041] Figure 4 is the 6 HNMR (400 MHz, CDCl 1 ) chromatogram of MPEG 3 -OH.

[0042] Figure 5 is the GC chromatogram of MPEG 7 -OH.

[0043] Figure 6 is the 7 HNMR (400 MHz, CDCl 1 ) chromatogram of MPEG 3 -OH.

[0044] Figure 7 is the UPLC-ELSD chromatogram of MPEG 8 -OH.

[0045] Figure 8 is the 8 HNMR (400 MHz, CDCl 1 ) chromatogram of MPEG 3 -OH.

[0046] Figure 9 is the UPLC-ELSD chromatogram of MPEG 9 -OH.

[0047] Figure 10 is MPEG 9 of -OH 1 HNMR(600 MHz, CDCl 3 ) spectrum.

[0048] Figure 11 is MPEG 10 UPLC-ELSD spectrum of -OH.

[0049] Figure 12 is MPEG 10 of -OH 1 HNMR(600 MHz, CDCl 3 ) spectrum.

[0050] Figure 13 is N 3 -PEG 5 GC spectrum of -OH.

[0051] Figure 14 is N 3 -PEG 5 of -OH 1 HNMR(600 MHz, CDCl 3 ) spectrum.

[0052] Figure 15 is N 3 -PEG 6 of -OH 1 HNMR(600 MHz, CDCl 3 ) spectrum.

[0053] Figure 16 is N 3 -PEG 7 of -OH 1 HNMR(600 MHz, CDCl 3 ) spectrum.

[0054] Figure 17 is N 3 -PEG 8 of -OH 1 HNMR(600 MHz, CDCl 3 ) spectrum.

[0055] Figure 18 is BnO-PEG 5 GC spectrum of -OH.

[0056] Figure 19 is BnO-PEG 5 of -OH 1 HNMR(600 MHz, CDCl 3)Figure.

[0057] Figure 20 is the GC chromatogram of propargyloxy-PEG 5 -OH.

[0058] Figure 21 is the 5 GC chromatogram of propargyloxy-PEG 1 -OH in 3 HNMR (600 MHz, CDCl

[0059] Figure 22 is the GC chromatogram of BocNH-PEG 3 -OH.

[0060] Figure 23 is the 3 GC chromatogram of BocNH-PEG 1 -OH in 3 HNMR (600 MHz, CDCl

[0061] Figure 24 is the GC chromatogram of CbzNH-PEG 3 -OH.

[0062] Figure 25 is the 3 GC chromatogram of CbzNH-PEG 1 -OH in 3 HNMR (600 MHz, CDCl

[0063] Figure 26 is the GC chromatogram of 2,5,8,11,14-pentaoxaheptadecan-16-ol.

[0064] Figure 27 is the 1 HNMR (600 MHz, CDCl 3 ) chromatogram of 2,5,8,11,14-pentaoxaheptadecan-16-ol.

[0065] Figure 28 is the GC chromatogram of (R)-2,5,8,11,14-pentaoxaheptadecan-16-ol.

[0066] Figure 29 is the 1 HNMR (600 MHz, CDCl 3 ) chromatogram of (R)-2,5,8,11,14-pentaoxaheptadecan-16-ol.

[0067] Figure 30 is the GC chromatogram of 2,5,8,11,14-pentaoxaoctadecan-16-ol.

[0068] Figure 31 is of 2,5,8,11,14-pentaoxaoctadecan-16-ol 1 HNMR(600MHz,CDCl 3 ) graph.

[0069] Figure 32 is the GC graph of MPEG 5 -NH 2 .

[0070] Figure 33 is the 5 -NH 2 of MPEG 1 HNMR(600MHz,CDCl 3 ) graph. Specific Embodiments

[0071] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments, but the protection scope of the present invention is not limited to these embodiments only.

[0072] Example 1: Preparation of Methoxy-Terminated Monodisperse Polyethylene Glycol

[0073] 1. Preparation of MPEG 4 -OH from MPEG 5 -OH

[0074]

[0075] Under a nitrogen atmosphere, MPEG 4 -OH(2000.0 g, 9.6 mol, 1.0 eq.), THF(16.0 L), and vinyl sulfate(1668.6 g, 13.4 mol, 1.4 eq.) were successively added to a 20 L reaction kettle. After stirring and dissolving, the system was cooled to -20 °C, and then NaH(60% in oil, 576.2 g, 14.4 mol, 1.5 eq.) was added. After addition, the reaction was continued to stir at -20 °C for 1 hour. The reaction was monitored by TLC to be complete (TLC condition: DCM / MeOH = 20 / 1). Methanol(233.0 mL, 0.6 eq.) was added to the system to quench the reaction. THF was removed by concentration. The obtained concentrate was diluted with water(16.0 L), and the aqueous phase was extracted with EA(4.0 L × 2 times). The aqueous phases were combined and concentrated; the aqueous phase concentrate was dissolved in THF(16.0 L), and concentrated H 2 SO 4 (98%, 520.0 mL, 1.0 eq.) was slowly added, and the mixture was refluxed and hydrolyzed for 2 hours. The hydrolysis of the intermediate was monitored by TLC to be complete (TLC condition: DCM / MeOH = 20 / 1). The reaction solution was cooled and concentrated. The obtained concentrate was saturated with NaHCO 3In an aqueous solution, the aqueous phase was successively extracted with PE and DCM, and the DCM phases were combined. The combined DCM phase was dried over anhydrous Na 2 SO 4 and filtered. The resulting filtrate was concentrated to obtain 2222.0 g of pale yellow oily liquid MPEG 5 -OH, with a yield of 91.7%. The purity of the product was determined by GC to be 99.82% (see Figure 1 ), and the structural characterization data were as follows: 1 HNMR(CDCl 3 , 400 MHz): δ 3.74 - 3.70 (m, 2H), 3.66 - 3.59 (m, 16H), 3.54 (t, J = 4.0 Hz, 2H), 3.37 (s, 3H), 2.55 (t, J = 4.0 Hz, 1H), see Figure 2 ; 13 CNMR(CDCl 3 , 150 MHz): δ 72.41, 71.77, 70.47, 70.45, 70.41, 70.35, 70.21, 61.52, 58.87.

[0076] 2. Preparation of MPEG 5 -OH from MPEG 6 -OH

[0077]

[0078] Under a nitrogen atmosphere, MPEG 5 -OH (100.0 g, 396.4 mmol, 1.0 eq.), THF (660.0 mL), and ethylene sulfate (69.0 g, 555.0 mmol, 1.4 eq.) were successively added to a 2 L three-necked flask. After stirring to dissolve, the system was cooled to -20 °C, and then NaH (60% in oil, 24.0 g, 594.6 mmol, 1.5 eq.) was added. After addition, the reaction was continued to stir at -20 °C for 1 hour. The reaction was monitored by TLC to be complete (TLC condition: DCM / MeOH = 20 / 1). Methanol (10.0 mL, 0.6 eq.) was added to the system to quench the reaction, and THF was removed by concentration. The resulting concentrate was diluted with water (600.0 mL), and the aqueous phase was extracted with EA (100.0 mL × 2 times). The aqueous phases were combined and concentrated; the aqueous phase concentrate was dissolved in THF (660.0 mL), and concentrated H 2 SO 4 (98%, 21.0 mL, 1.0 eq.) was slowly added, and the mixture was refluxed and hydrolyzed for 2 hours. The hydrolysis of the intermediate was monitored by TLC to be complete (TLC condition: DCM / MeOH = 20 / 1). The reaction solution was cooled and concentrated, and the resulting concentrate was washed with saturated NaHCO 3In an aqueous solution, the aqueous phase was successively extracted with PE and DCM, and the DCM phases were combined. After drying with anhydrous Na 2 SO 4 and filtering, the obtained filtrate was concentrated to obtain 107.3 g of pale yellow oily liquid MPEG 6 -OH, with a yield of 91.3%. The purity of the product determined by GC was 99.75% (see Figure 3 ), and the structure characterization data were as follows: 1 HNMR(CDCl 3 , 400 MHz): δ 3.74 - 3.70 (m, 2H), 3.65 - 3.59 (m, 20H), 3.54 (t, J = 4.0 Hz, 2H), 3.37 (s, 3H), 2.56 (t, J = 4.0 Hz, 1H), see Figure 4 ; 13 CNMR(CDCl 3 , 150 MHz): δ 72.39, 71.76, 70.45, 70.43, 70.41, 70.39, 70.34, 70.19, 61.50, 58.85.

[0079] 3. Preparation of MPEG 6 -OH from MPEG 7 -OH

[0080]

[0081] Under a nitrogen atmosphere, MPEG 6 -OH (100.0 g, 337.4 mmol, 1.0 eq.), THF (482.0 mL), and ethylene sulfate (58.6 g, 472.4 mmol, 1.4 eq.) were successively added to a 1 L three-necked flask. After stirring and dissolving, the system was cooled to -20 °C, and then NaH (60% in oil, 20.2 g, 506.1 mmol, 1.5 eq.) was added. After addition, the reaction was continued to stir at -20 °C for 1 hour. The reaction was monitored by TLC to be complete (TLC condition: DCM / MeOH = 20 / 1). Methanol (8.2 mL, 0.6 eq.) was added to the system to quench the reaction, and THF was removed by concentration. The obtained concentrate was diluted with water (500.0 mL), and the aqueous phase was extracted with EA (100.0 mL × 2 times). The aqueous phases were combined and concentrated; the aqueous phase concentrate was dissolved in THF (482.0 mL), and concentrated H 2 SO 4 (98%, 22.0 mL, 1.2 eq.) was slowly added, and the mixture was refluxed and hydrolyzed for 2 hours. The hydrolysis of the intermediate was monitored by TLC to be complete (TLC condition: DCM / MeOH = 20 / 1). The reaction solution was cooled and concentrated, and the obtained concentrate was saturated with NaHCO 3In an aqueous solution, the aqueous phase was successively extracted with PE and DCM, and the DCM phases were combined. The combined DCM phase was dried over anhydrous Na 2 SO 4 and filtered. The resulting filtrate was concentrated to obtain a pale yellow oily liquid MPEG 7 -OH, 97.4 g, with a yield of 84.8%. The purity of the product was determined by GC to be 99.69% (see Figure 5 ), and the structure characterization data were as follows: 1 HNMR (CDCl 3 , 400 MHz): δ 3.74 - 3.70 (m, 2H), 3.65 - 3.59 (m, 24H), 3.54 (t, J = 4.0 Hz, 2H), 3.37 (s, 3H), 2.59 (t, J = 8.0 Hz, 1H), see Figure 6 ; 13 CNMR (CDCl 3 , 150 MHz): δ 72.41, 71.77, 70.46, 70.45, 70.41, 70.34, 70.19, 61.51, 58.87.

[0082] 4. Preparation of MPEG 7 -OH from MPEG 8 -OH

[0083]

[0084] Under a nitrogen atmosphere, MPEG 7 -OH (100.0 g, 293.8 mmol, 1.0 eq.), THF (490.0 mL), and ethylene sulfate (72.9 g, 587.6 mmol, 2.0 eq.) were successively added to a 1 L three-necked flask. After stirring to dissolve, the system was cooled to -20 °C, and then NaH (60% in oil, 17.6 g, 440.7 mmol, 1.5 eq.) was added. After addition, the reaction was continued by stirring at -20 °C for 1 h. The reaction was monitored by TLC to completion (TLC condition: DCM / MeOH = 20 / 1). Methanol (7.0 mL, 0.6 eq.) was added to the system to quench the reaction. THF was removed by concentration. The resulting concentrate was diluted with water (490.0 mL), and the aqueous phase was extracted with EA (100.0 mL × 2 times). The aqueous phases were combined and concentrated; the aqueous phase concentrate was dissolved in THF (490.0 mL), and concentrated H 2 SO 4 (98%, 19.2 mL, 1.2 eq.) was slowly added, and the mixture was refluxed and hydrolyzed for 2 h. The hydrolysis of the intermediate was monitored by TLC to completion (TLC condition: DCM / MeOH = 20 / 1). The reaction solution was cooled and concentrated. The resulting concentrate was washed with saturated NaHCO 3In the aqueous solution, the aqueous phase was successively extracted with PE and DCM, and the DCM phases were combined. The combined DCM phase was dried over anhydrous Na 2 SO 4 and then filtered. The obtained filtrate was concentrated to give a pale yellow oily liquid MPEG 8 -OH, 88.6 g, with a yield of 78.4%. The purity of the product was determined by UPLC-ELSD to be 99.94% (see Figure 7 ), and the structure characterization data were as follows: 1 1H NMR (CDCl 3 , 400 MHz): δ 3.74 - 3.70 (m, 2H), 3.66 - 3.60 (m, 28H), 3.54 (t, J = 4.0 Hz, 2H), 3.37 (s, 3H), 2.54 (t, J = 4.0 Hz, 1H), see Figure 8 ; 13 13C NMR (CDCl 3 , 150 MHz): δ 72.42, 71.80, 70.49, 70.47, 70.44, 70.38, 70.22, 61.55, 58.90.

[0085] 5. Preparation of MPEG 8 -OH to MPEG 9 -OH

[0086]

[0087] Under a nitrogen atmosphere, MPEG 8 -OH (100.0 g, 260.1 mmol, 1.0 eq.), THF (650.0 mL), and ethylene sulfate (64.6 g, 520.2 mmol, 2.0 eq.) were successively added to a 1 L three-necked flask. After stirring to dissolve, the system was cooled to -20 °C, and then NaH (60% in oil, 15.6 g, 390.2 mmol, 1.5 eq.) was added. After the addition, the reaction was continued to stir at -20 °C for 1 h. The reaction was monitored by TLC to be complete (TLC condition: DCM / MeOH = 20 / 1). Methanol (6.0 mL, 0.6 eq.) was added to the system to quench the reaction. THF was removed by concentration. The obtained concentrate was diluted with water (650.0 mL), and the aqueous phase was extracted with EA (200.0 mL × 2 times). The aqueous phases were combined and concentrated; the aqueous phase concentrate was dissolved in THF (650.0 mL), and concentrated H 2 SO 4 (98%, 14.0 mL, 1.0 eq.) was added, and the mixture was refluxed and hydrolyzed for 2 h. The hydrolysis of the intermediate was monitored by TLC to be complete (TLC condition: DCM / MeOH = 20 / 1). The reaction solution was cooled and concentrated. The obtained concentrate was washed with saturated NaHCO 3In an aqueous solution, the aqueous phase was successively extracted with PE and DCM. The DCM phases were combined and dried over anhydrous Na 2 SO 4 After drying, it was filtered, and the obtained filtrate was concentrated to obtain a pale yellow oily liquid MPEG 9 -OH 81.9 g, with a yield of 73.5%. The purity of the product was determined by UPLC-ELSD to be 99.55% (see Figure 9 ), and the structural characterization data were as follows: 1 HNMR(CDCl 3 , 600 MHz): δ 3.72 (t, J = 6.0 Hz, 2H), 3.67 - 3.65 (m, 30H), 3.61 (t, J = 6.0 Hz, 2H), 3.54 (t, J = 6.0 Hz, 2H), 3.38 (s, 3H), 2.23 (s, 1H), see Figure 10 ; 13 CNMR(CDCl 3 , 150 MHz): δ 72.42, 71.81, 70.49, 70.48, 70.45, 70.39, 70.23, 61.56, 58.90.

[0088] 6. Preparation of MPEG 9 -OH to MPEG 10 -OH

[0089]

[0090] Under a nitrogen atmosphere, MPEG 9 -OH (100.0 g, 233.3 mmol, 1.0 eq.), THF (583.0 mL), and ethylene sulfate (57.9 g, 466.6 mmol, 2.0 eq.) were successively added to a 1 L three-necked flask. After stirring and dissolving, the system was cooled to -20 °C, and then NaH (60% in oil, 0.7 g, 17.6 mmol, 1.5 eq.) was added. After addition, the reaction was continued to stir at -20 °C for 1 hour. The reaction was monitored by TLC to be complete (TLC condition: DCM / MeOH = 20 / 1). Methanol (6.0 mL, 0.6 eq.) was added to the system to quench the reaction, and THF was removed by concentration. The obtained concentrate was diluted with water (583.0 mL), and the aqueous phase was extracted with EA (100.0 mL × 2 times). The aqueous phases were combined and concentrated; the aqueous phase concentrate was dissolved in THF (583.0 mL), and concentrated H 2 SO 4 (98%, 13.0 mL, 1.0 eq.) was slowly added, and the mixture was refluxed and hydrolyzed for 2 hours. The hydrolysis of the intermediate was monitored by TLC to be complete (TLC condition: DCM / MeOH = 20 / 1). The reaction solution was cooled and concentrated, and the obtained concentrate was treated with saturated NaHCO 3In an aqueous solution, the aqueous phase was successively extracted with PE and DCM. The DCM phases were combined and dried over anhydrous Na 2 SO 4 After drying, the mixture was filtered, and the obtained filtrate was concentrated to give a colorless oily liquid MPEG 10 -OH, 78.2 g, with a yield of 70.9%. The purity of the product was determined by UPLC-ELSD to be 98.73% (see Figure 11 ), and the structure characterization data were as follows: 1 HNMR(CDCl 3 , 600 MHz): δ 3.72 (t, J = 6.0 Hz, 2H), 3.67 - 3.65 (m, 30H), 3.61 (t, J = 6.0 Hz, 2H), 3.54 (t, J = 6.0 Hz, 2H), 3.38 (s, 3H), 2.23 (s, 1H), see Figure 12 ; 13 CNMR(CDCl 3 , 150 MHz): δ 72.42, 71.81, 70.49, 70.48, 70.45, 70.39, 70.23, 61.56, 58.90.

[0091] Example 2: Preparation of azide-terminated monodisperse polyethylene glycol

[0092] 1. Preparation of N 3 -PEG 4 -OH from N 3 -PEG 5 -OH

[0093]

[0094] Using the feeding method and feeding ratio for preparing MPEG 4 -OH from MPEG 5 -OH in Example 1, 1000.0 g of N 3 -PEG 4 -OH was used for click chain growth to obtain the product N 3 -PEG 5 -OH, which was 1083.5 g of a pale yellow oily liquid with a yield of 90.2%. The purity of the product was determined by GC to be 99.16% (see Figure 13 ), and the structure characterization data were as follows: 1 HNMR(CDCl 3 , 600 MHz): δ 3.72 (t, J = 6.0 Hz, 2H), 3.68 - 3.66 (m, 14H), 3.60 (t, J = 6.0 Hz, 2H), 3.39 (t, J = 6.0 Hz, 2H), 2.34 (s, 1H), see Figure 14 ; 13CNMR(CDCl 3 , 150 MHz): δ 72.47, 70.59, 70.53, 70.50, 70.35, 70.46, 70.22, 69.94, 61.59, 50.57。

[0095] 2. Preparation of N 3 -PEG 5 -OH to N 3 -PEG 6 -OH

[0096]

[0097] Using the feeding method and feeding ratio for preparing MPEG 4 -OH to MPEG 5 -OH in Example 1, 100.0 g of N 3 -PEG 5 -OH was used for click chain growth to obtain the product N 3 -PEG 6 -OH, which is 102.1 g of pale yellow oily liquid with a yield of 87.5%. The purity of the product was determined by GC to be 99.75%. The structure characterization data are as follows: 1 H NMR(CDCl 3 , 600 MHz): δ 3.73 - 3.69 (m, 2H), 3.68 - 3.65 (m, 18H), 3.60 (t, J = 6.0 Hz, 2H), 3.38 (t, J = 6.0 Hz, 2H), 2.71 (t, J = 6.0 Hz, 1H), see Figure 15 ; 13 CNMR(CDCl 3 , 150 MHz): δ 72.43, 70.56, 70.50, 70.46, 70.43, 70.23, 69.92, 61.58, 50.56。

[0098] 3. Preparation of N 3 -PEG 6 -OH to N 3 -PEG 7 -OH

[0099]

[0100] Using the feeding method and feeding ratio for preparing MPEG 4 -OH to MPEG 5 -OH in Example 1, 100.0 g of N 3 -PEG 6 -OH was used for click chain growth to obtain the product N 3 -PEG7 -OH, namely 104.6 g of light yellow oily liquid, with a yield of 91.5%, and the purity of the product determined by GC was 99.14%. The structural characterization data are as follows: 1 HNMR(CDCl 3 , 600 MHz): δ 3.73 - 3.71 (m, 2H), 3.68 - 3.65 (m, 22H), 3.61 (t, J = 6.0 Hz, 2H), 3.39 (t, J = 6.0 Hz, 2H), 2.70 (t, J = 6.0 Hz, 1H), see Figure 16 ; 13 CNMR(CDCl 3 , 150 MHz): δ 72.43, 70.54, 70.50, 70.48, 70.46, 70.42, 70.39, 70.18, 69.89, 61.53, 50.54.

[0101] 4. Preparation of benzyl - terminated monodisperse polyethylene glycol 3 -PEG 7 -OH was used to prepare N 3 -PEG 8 -OH

[0102]

[0103] The feeding method and feeding ratio for preparing MPEG 4 -OH from MPEG 5 -OH in Example 1 were adopted. 100.0 g of N 3 -PEG 7 -OH was used for click - chain growth to obtain the product N 3 -PEG 8 -OH, namely 100.5 g of light yellow oily liquid, with a yield of 89.3%, and the purity of the product determined by GC was 99.13%. The structural characterization data are as follows: 1 HNMR(CDCl 3 , 600 MHz): δ 3.74 - 3.70 (m, 2H), 3.68 - 3.64 (m, 26H), 3.60 (t, J = 6.0 Hz, 2H), 3.38 (t, J = 6.0 Hz, 2H), 2.63 (t, J = 6.0 Hz, 1H), see Figure 17 ; 13 CNMR(CDCl 3 , 150 MHz): δ 72.41, 70.51, 70.49, 70.46, 70.44, 70.39, 70.37, 70.16, 69.87, 61.50, 50.50.

[0104] Example 3: Preparation of benzyl - terminated monodisperse polyethylene glycol

[0105] From BnO-PEG 4 -OH to prepare BnO-PEG 5 -OH

[0106]

[0107] Adopt the feeding method and feeding ratio of preparing MPEG 4 -OH from MPEG 5 -OH in Example 1. Use 100.0 g of BnO-PEG 4 -OH for click chain growth to obtain the product BnO-PEG 5 -OH, that is, 104.0 g of pale yellow oily liquid, with a yield of 90.0%. The purity of the product determined by GC is 99.61% (see Figure 18 ), and the structure characterization data are as follows: 1 HNMR(CDCl 3 , 600 MHz): δ 7.34 - 7.27 (m, 5H), 4.56 (s, 2H), 3.71 (t, J = 6.0 Hz, 2H), 3.68 - 3.66 (m, 16H), 3.59 (t, J = 6.0 Hz, 2H), 2.72 (s, 1H), see Figure 19 ; 13 C NMR(CDCl 3 , 150 MHz): δ 138.11, 128.22, 127.61, 127.45, 73.07, 72.40, 70.48, 70.44, 70.41, 70.17, 69.26, 61.51.

[0108] Example 4: Preparation of propargyl-capped monodisperse polyethylene glycol

[0109] From propargyloxy-PEG 4 -OH to prepare propargyloxy-PEG 5 -OH

[0110]

[0111] Adopt the feeding method and feeding ratio of preparing MPEG 4 -OH from MPEG 5 -OH in Example 1. Use 100.0 g of propargyloxy-PEG 4 -OH for click chain growth to obtain the product propargyloxy-PEG 5 -OH, that is, 102.1 g of pale yellow oily liquid, with a yield of 85.8%. The purity of the product determined by GC is 99.56% (see Figure 20 ), and the structure characterization data are as follows: 1 HNMR(CDCl3 , 600 MHz): δ 4.20 (s, 2H), 3.73 - 3.66 (m, 18H), 3.60 (t, J = 6.0 Hz, 2H), 2.62 (s, 1H), 2.43 (s, 1H), see Figure 21 ; 13 C NMR (CDCl 3 , 150 MHz): δ 79.59, 74.50, 72.48, 70.51, 70.46, 70.29, 70.23, 69.00, 61.58, 58.28.

[0112] Example 5: Preparation of tert-Butyl Carbamate-Terminated Monodisperse Polyethylene Glycol

[0113] From BocNH-PEG 2 -OH to prepare BocNH-PEG 3 -OH

[0114]

[0115] Under a nitrogen atmosphere, BocNH-PEG 2 -OH (100.0 g, 487.1 mmol, 1.0 eq.), THF (811.0 mL), and vinyl sulfate (84.6 g, 681.9 mmol, 1.4 eq.) were successively added to a 2 L three-necked flask. After stirring and dissolving, the system was cooled to -20 °C, and then NaH (60% in oil, 23.4 g, 584.5 mmol, 1.2 eq.) was added. After addition, the reaction was continued to stir at -20 °C for 1 hour. The reaction was monitored by TLC to be complete (TLC condition: DCM / MeOH = 20 / 1). Methanol (6.0 mL, 0.3 eq.) was added to the system to quench the reaction, and THF was removed by concentration. The obtained concentrate was diluted with water (800.0 mL), and the aqueous phase was extracted with EA (300.0 mL × 2 times). The aqueous phases were combined and concentrated; the aqueous phase concentrate was dissolved in THF (811.0 mL), and concentrated H 2 SO 4 (98%, 26.0 mL, 0.3 eq.) was slowly added, and the mixture was refluxed and hydrolyzed for 4 hours. The hydrolysis of the intermediate was monitored by TLC to be complete (TLC condition: DCM / MeOH = 20 / 1). The reaction solution was cooled and concentrated. The obtained concentrate was neutralized with saturated NaHCO 3 aqueous solution, and the aqueous phase was successively extracted with PE and DCM. The DCM phases were combined and dried over anhydrous Na 2 SO 4 and filtered. The obtained filtrate was concentrated to obtain 97.0 g of the product BocNH-PEG 3 -OH, with a yield of 80% and a GC purity of 99.41% (see Figure 22), and the structural characterization data are as follows: 1 HNMR(CDCl 3 , 400 MHz): δ 3.75 - 3.74 (m, 2H), 3.66 - 3.61 (m, 6H), 3.56 (t, J = 6.0 Hz, 2H), 3.32 (s, 2H), 2.06 (s, 1H), 1.45 (s, 9H), see Figure 23 ; 13 CNMR(CDCl 3 , 150 MHz): δ 156.01, 79.17, 72.56, 70.32, 70.22, 70.16, 61.57, 40.27, 28.35.

[0116] Example 6: Preparation of Benzyloxycarbonylamino-Terminated Monodisperse Polyethylene Glycol

[0117] From CbzNH-PEG 2 -OH to prepare CbzNH-PEG 3 -OH

[0118]

[0119] Under a nitrogen atmosphere, CbzNH-PEG 2 -OH (100.0 g, 417.9 mmol, 1.0 eq.), THF (1044.0 mL), and vinyl sulfate (72.6 g, 585.1 mmol, 1.4 eq.) were successively added to a 2 L three-necked flask. After stirring and dissolving, the system was cooled to -20 °C, and then NaH (60% in oil, 21.7 g, 543.3 mmol, 1.3 eq.) was added. After addition, the reaction was continued to stir at -20 °C for 1 hour. The reaction was monitored by TLC to be complete (TLC condition: DCM / MeOH = 20 / 1). Methanol (7.0 mL, 0.4 eq.) was added to the system to quench the reaction, and THF was removed by concentration. The obtained concentrate was diluted with water (1000.0 mL), and the aqueous phase was extracted with EA (200.0 mL × 2 times). The aqueous phases were combined and concentrated; the aqueous phase concentrate was dissolved in THF (1044.0 mL), and concentrated H 2 SO 4 (98%, 27.0 mL, 0.2 eq.) was slowly added, and the reaction was refluxed and hydrolyzed for 4 hours. The hydrolysis of the intermediate was monitored by TLC to be complete (TLC condition: DCM / MeOH = 20 / 1). The reaction solution was cooled and concentrated. The obtained concentrate was neutralized with a saturated NaHCO 3 aqueous solution, and the aqueous phase was successively extracted with PE and DCM. The DCM phases were combined and dried over anhydrous Na 2 SO 4 and filtered. The obtained filtrate was concentrated to obtain a pale yellow oily liquid CbzNH-PEG3 -OH 98.6 g, with a yield of 83.3% and a GC purity of 99.88% (see Figure 24 ), and the structural characterization data are as follows: 1 HNMR(CDCl 3 , 600 MHz): δ 7.36 - 7.31 (m, 5H), 5.40 (s, 1H), 5.10 (s, 2H), 3.71 (s, 2H), 3.63 - 3.58 (m, 8H), 3.40 (s, 2H), 2.15 - 2.09 (m, 1H), see Figure 25 ; 13 CNMR(CDCl 3 , 150 MHz): δ 156.50, 136.58, 128.49, 128.13, 128.09, 72.56, 70.37, 70.30, 70.11, 66.67, 61.66, 40.85.

[0120] Example 7: Preparation of Monodisperse Polyethylene Glycol with Main Chain Methyl Substitution

[0121] Preparation of 2,5,8,11,14 - pentaoxaheptadecan - 16 - ol from MPEG 4 -OH

[0122]

[0123] Under a nitrogen atmosphere, MPEG 4 -OH (100.0 g, 480.1 mmol, 1.0 eq.), THF (800.0 mL), and 4 - methyl - 1,3,2 - dioxathiane - 2,2 - dioxide (92.8 g, 672.1 mmol, 1.4 eq.) were successively added to a 2 L three - necked flask. After stirring and dissolving, the system was cooled to -20 °C, and then NaH (60% in oil, 28.8 g, 720.2 mmol, 1.5 eq.) was added. After addition, the reaction was continued by stirring at -20 °C for 1 hour. The reaction was monitored by TLC to be complete (TLC condition: DCM / MeOH = 20 / 1). Methanol (12.0 mL, 0.6 eq.) was added to the system for reaction, and THF was removed by concentration. The obtained concentrate was diluted with water (800.0 mL), and the aqueous phase was extracted with EA (200.0 mL × 2 times). The aqueous phases were combined and concentrated; the aqueous phase concentrate was dissolved in THF (800.0 mL), and concentrated H 2 SO 4 (98%, 26.0 mL, 1.0 eq.) was slowly added, and the mixture was refluxed for hydrolysis for 2 hours. The hydrolysis of the intermediate was monitored by TLC to be complete (TLC condition: DCM / MeOH = 20 / 1). The reaction solution was cooled and concentrated, and the obtained concentrate was washed with saturated NaHCO 3In the aqueous solution, the aqueous phase was successively extracted with PE and DCM, and the DCM phases were combined. After drying with anhydrous Na 2 SO 4 and filtering, the obtained filtrate was concentrated to obtain 106.1 g of a pale yellow oily liquid, 2,5,8,11,14-pentaoxaheptadecan-16-ol, with a yield of 83.0%. The purity of the product was determined by GC to be 96.04% (see Figure 26 ), and the by-product was an isomer. The structure characterization data of the target product are as follows: 1 HNMR(CDCl 3 , 600 MHz): δ 3.99 - 3.93 (m, 1H), 3.68 - 3.63 (m, 14H), 3.54 (t, J = 6.0 Hz, 2H), 3.49 (dd, J 大 = 1.2 Hz, J 小 = 6.0 Hz, 1H), 3.37 (s, 3H), 3.25 (t, J = 6.0 Hz, 1H), 2.70 (s, 1H), 1.12 (d, J = 6.0 Hz, 3H), see Figure 27 ; 13 CNMR(CDCl 3 , 150 MHz): δ 76.74, 71.72, 70.40, 70.37, 70.34, 70.31, 66.00, 58.84, 18.39.

[0124] Example 8: Preparation of Optically Active Main Chain Methyl Substituted Monodisperse Polyethylene Glycol

[0125] (R)-2,5,8,11,14-Pentaoxaheptadecan-16-ol was prepared from MPEG 4 -OH

[0126]

[0127] In this example, the racemic 4-methyl-1,3,2-dioxathiane-2,2-dioxide in Example 7 was replaced with the optically active (R)-4-methyl-1,3,2-dioxathiane-2,2-dioxide to obtain 108.2 g of a pale yellow oily liquid, (R)-2,5,8,11,14-pentaoxaheptadecan-16-ol, with a yield of 84.7%. The purity of the product was determined by GC to be 96.09% (see Figure 28 ), and the by-product was an isomer. The structure characterization data of the target product are as follows: 1 HNMR(CDCl 3 , 600 MHz): δ 4.00 - 3.93 (m, 1H), 3.69 - 3.62 (m, 14H), 3.54 (t, J = 6.0 Hz, 2H), 3.49 (dd, J 大 = 1.2 Hz, J小 = 6.0 Hz, 1H), 3.37 (s, 3H), 3.23 (t, J = 1.2 Hz, 1H), 2.87 (s, 1H), 1.11 (d, J = 6.0 Hz, 3H), see Figure 29 ; 13 C NMR (CDCl 3 , 150 MHz): δ 76.93, 71.81, 70.49, 70.45, 70.43, 70.41, 70.39, 66.10, 58.91, 18.43.

[0128] Example 9: Preparation of Main Chain Ethyl Substituted Monodisperse Polyethylene Glycol

[0129] From MPEG 4 -OH to prepare 2,5,8,11,14-pentaoxaoctadec-16-ol

[0130]

[0131] In this example, 4-ethyl-1,3,2-dioxathiane-2,2-dioxide was used to replace 4-methyl-1,3,2-dioxathiane-2,2-dioxide in Example 7 in an equimolar amount. The other steps were the same as those in Example 7. 114.5 g of 2,5,8,11,14-pentaoxaoctadec-16-ol was obtained as a pale yellow oily liquid, with a yield of 85.1%. The purity of the product determined by GC was 98.46% (see Figure 30 ), and the by-product was an isomer. The structure characterization data of the target product are as follows: 1 H NMR (CDCl 3 , 600 MHz): δ 3.71 - 3.63 (m, 15H), 3.55 - 3.52 (m, 3H), 3.37 (s, 3H), 3.30 (t, J = 6.0 Hz, 1H), 2.59 (s, 1H), 1.49 - 1.42 (m, 2H), 0.95 (t, J = 6.0 Hz, 3H), see Figure 31 ; 13 C NMR (CDCl 3 , 150 MHz): δ 75.30, 71.68, 71.25, 70.33, 70.27, 58.79, 25.79, 9.76.

[0132] Example 10

[0133] From MPEG 4 -OH to prepare MPEG 5 -NH 2

[0134]

[0135] In this example, 1,2,3-oxathiazolidine-3-carboxylic acid tert-butyl ester 2,2-dioxide was used to replace 4-methyl-1,3,2-dioxythiazolidine-2,2-dioxide in Example 7. The other steps were the same as those in Example 7 to obtain a light yellow oily liquid MPEG. 5 -NH 2 89.6g, yield 74.2%, GC determination of product purity 99.56% (see Figure 32 ), the structural characterization data is: 1 HNMR (CDCl 3 ,600MHz): δ5.32(s,2H),3.88(t,J=6.0Hz,2H),3.74(t,J=6.0Hz,2H),3.69 -3.63(m,12H),3.56(t,J=6.0Hz,2H),3.39(s,3H),3.10(t,J=6.0Hz,2H), see Figure 33 ; 13 CNMR (CDCl 3 ,150MHz): δ71.45,70.27,70.01,69.97,69.94,69.83,69.77,67.44,58.84,40.16.

[0136] In the above examples, monodisperse polyethylene glycol containing representative end-capping groups such as methoxy, benzyloxy, azido, propargyloxy, tert-butyl carbamate, benzyl carbamate, etc. is listed as the click chain growth raw material, which does not limit the substrate of the present invention in any form. All variations that can be directly derived or associated with the contents disclosed by ordinary or professional technicians in this field should be considered as the protection scope of the present invention.

Claims

1. A method for preparing high-purity monodisperse polyethylene glycol derivatives, characterized in that The method comprises the following steps: Step 1: Monodisperse oligoethylene glycol derivative R1-PEG n -OH and vinyl sulfate or substituted vinyl sulfate undergo nucleophilic substitution reaction in a solvent under the action of a base to obtain a sulfonate intermediate, wherein the temperature of the nucleophilic substitution reaction is -20°C and the reaction time is 1 to 2 hours; after extraction, the sulfonate intermediate is refluxed and hydrolyzed with concentrated sulfuric acid in tetrahydrofuran to obtain a high-purity chain extension product R1-PEG with one more ethylene glycol unit. n+1 -OH; the reaction formula is as follows: In the formula, R1 represents any one of -N3, -Cl, C1-C4 alkoxy, -OBn, -OPh, -NHBoc, -NHCbz, -NHCOPh, -NHTs, C2-C4 alkynyloxy, and C2-C4 alkenyloxy; n is an integer ≥ 2; R represents any one of -H, -F, -Cl, -CH3, -CH2CH3, -Bn, -Ph, -CH2Cl, -CH2OBn, -CH2OTBS, -CH2N3, and -CH2NBn2; Step 2: subjecting the chain-extended product to multiple iterative reactions according to the method of step 1 to obtain a long-chain high-purity monodisperse polyethylene glycol derivative having more ethylene glycol units.

2. The method for preparing high-purity monodisperse polyethylene glycol derivatives according to claim 1, characterized in that: The R1 represents any one of -N3, -Cl, -OCH3, -OtBu, -OBn, -OPh, -NHBoc, -NHCbz, -NHCOPh, -NHTs, -OCH2C≡CH, and -OCH2CH=CH2.

3. The method for preparing high-purity monodisperse polyethylene glycol derivatives according to claim 1, characterized in that: In step 1, the monodisperse oligoethylene glycol derivative R1-PEG n The molar ratio of -OH to vinyl sulfate or substituted vinyl sulfate and base is 1: 1.2-2.0: 1.2-1.

5.

4. The method for preparing high-purity monodisperse polyethylene glycol derivatives according to claim 1 or 3, characterized in that: In step 1, the base is any one of NaOH, KOH, NaH, NaOtBu, and KOtBu.

5. The method for preparing high-purity monodisperse polyethylene glycol derivatives according to claim 1, characterized in that: In step 1, the solvent is tetrahydrofuran, ethylene glycol dimethyl ether, dioxane, N,N - Either dimethylformamide or dichloromethane.

6. The method for preparing high-purity monodisperse polyethylene glycol derivatives according to claim 1, characterized in that: In step 1, the monodisperse oligoethylene glycol derivative R1-PEG n The molar ratio of -OH to concentrated sulfuric acid is 1:0.2~1.

2.

7. The method for preparing high-purity monodisperse polyethylene glycol derivatives according to claim 1, characterized in that: In step 1, the reflux hydrolysis time is 2 to 4 hours.

Images