阅读说明：本技术 一种双重响应二肽超分子聚合物及其制备方法和应用 (Dual-response dipeptide supramolecular polymer and preparation method and application thereof ) 是由 王军 杨中兴 刘景� 王守信 孔令栋 李正澳 耿晓晴 宋豪杰 于 2021-09-01 设计创作，主要内容包括：本发明属于高分子化合物技术领域。本发明提供了一种双重响应二肽超分子聚合物,采用液相合成法,通过色氨酸甘氨酸二肽在N端修饰乏氧响应基元对硝基氯甲酸苄酯或2-(2-硝基咪唑-1-基)乙酸,在C端修饰温敏基元树枝状烷氧醚,在水溶液中经自组装形成双重敏感的超分子聚合物。该超分子聚合物制备简单,通过色氨酸荧光特征,在乏氧条件下荧光强度大大增强,同时该聚合物可以对药物的包覆,在乏氧条件下聚合物解组装实现药物的释放,为新型纳米药物的载体方面的研发提供了研究基础。(The invention belongs to the technical field of high molecular compounds. The invention provides a double-response dipeptide supramolecular polymer, which is formed by adopting a liquid phase synthesis method, modifying hypoxic response element p-nitro benzyl chloroformate or 2- (2-nitroimidazole-1-yl) acetic acid at an N end through tryptophan glycine dipeptide, modifying temperature-sensitive element dendritic alkoxy ether at a C end, and performing self-assembly in an aqueous solution. The supramolecular polymer is simple to prepare, the fluorescence intensity is greatly enhanced under the hypoxic condition through the tryptophan fluorescence characteristic, meanwhile, the polymer can coat the medicine, the release of the medicine is realized by the disassembly of the polymer under the hypoxic condition, and a research basis is provided for the research and development of a carrier of a novel nano medicine.)

1. A dual-response dipeptide supramolecular polymer is characterized in that the dual-response dipeptide supramolecular polymer is obtained by self-assembling a dual-response dipeptide supramolecular monomer in water;

the mass concentration of the dipeptide supramolecular polymer is 0.05-2 mg/mL;

the dual-response dipeptide supramolecular monomer has a structure shown in a formula 1:

r is

R' is hydrogen, methyl or isopropyl;

x is methyl, ethyl or

2. A monomer for preparing a dual-response dipeptide supramolecular polymer is characterized by having a structure shown in a formula 1:

r is

R' is hydrogen, methyl or isopropyl;

x is methyl, ethyl or

3. A method for the preparation of supramolecular monomers as claimed in claim 2, comprising the steps of:

(1) mixing tryptophan, 1-hydroxybenzotriazole, glycine methyl ester hydrochloride, dichloromethane, N-diisopropylethylamine and 1-ethyl- (3-dimethylaminopropyl) carbonyl diimine hydrochloride for condensation reaction to obtain a compound A;

(2) mixing the compound A, hydrated lithium hydroxide and a methanol aqueous solution, and carrying out substitution reaction to obtain a compound B;

(3) mixing the compound B, dendritic alkoxy ether, dichloromethane, 4-dimethylaminopyridine and 1-ethyl- (3-dimethylaminopropyl) carbonyl diimine hydrochloride, and carrying out esterification reaction to obtain a compound C;

(4) mixing the compound C, dichloromethane and trifluoroacetic acid, and carrying out substitution reaction to obtain a compound D;

(5) and (2) under an alkaline condition, mixing the compound D, the monomer and the reactant, and carrying out amidation reaction to obtain the dual-response dipeptide supramolecular monomer.

4. The method according to claim 3, wherein the tryptophan in the step (1) is Boc-L-tryptophan;

the molar ratio of tryptophan to 1-hydroxybenzotriazole to glycine methyl ester hydrochloride is 0.8-1.2: 1-1.4: 0.9 to 1.3;

the molar ratio of the tryptophan to the N, N-diisopropylethylamine is 1: 2 to 2.4;

the molar ratio of tryptophan to 1-ethyl- (3-dimethylaminopropyl) carbonyldiimine hydrochloride is 1: 1.2 to 1.4;

the dosage ratio of the tryptophan to the dichloromethane is 1 mmol: 3-10 mL;

the temperature of the condensation reaction in the step (1) is 20-30 ℃, and the time of the condensation reaction is 10-12 h.

5. The method according to claim 3 or 4, wherein the volume fraction of methanol in the aqueous methanol solution in the step (2) is 30 to 40%;

the molar ratio of the compound A to the hydrated lithium hydroxide is 1: 2-2.2;

the dosage ratio of the compound A to the methanol aqueous solution is 1 mmol: 5-10 g;

the temperature of the substitution reaction in the step (2) is 20-30 ℃, and the time of the substitution reaction is 2-3 h.

6. The process according to claim 5, wherein in step (3), the molar ratio between the dendrolated alkoxy ether and compound B is 1:1.3 to 1.5;

the dosage ratio of the compound B to dichloromethane is 1 mmol: 10-20 mL;

the molar ratio of the compound B to the 4-dimethylaminopyridine is 1: 0.3 to 0.5;

the molar ratio of the compound B to the 1-ethyl- (3-dimethylaminopropyl) carbonyldiimine hydrochloride is 1: 1.2 to 1.4;

the temperature of the esterification reaction in the step (3) is 20-30 ℃, and the time of the esterification reaction is 12-14 h.

7. The method according to claim 3 or 6, wherein the compound C and dichloromethane are used in a ratio of 1 mmol: 7-13 mL;

the molar ratio of the compound C to the trifluoroacetic acid is 1: 20 to 22;

the temperature of the substitution reaction in the step (4) is 20-30 ℃, and the time of the substitution reaction is 2.5-3.5 h.

8. The method according to claim 7, wherein the alkaline condition in the step (5) has a pH of 9 to 10;

the monomer is p-nitro benzyl chloroformate or 2- (2-nitroimidazole-1-yl) acetic acid;

the temperature of the amidation reaction in the step (5) is 20-30 ℃, and the time of the amidation reaction is 10-14 h.

9. The method of claim 8, wherein when the monomer is benzyl p-nitrochloroformate, the reactants comprise dichloromethane, and the compound D and dichloromethane are used in a ratio of 1 mmol: 35-45 mL;

the molar ratio of the compound D to the p-nitro benzyl chloroformate is 1: 1.1 to 1.2;

when the monomer is 2- (2-nitroimidazol-1-yl) acetic acid, the reactants comprise dichloromethane, 1-hydroxybenzotriazole and 1-ethyl- (3-dimethylaminopropyl) carbodiimides hydrochloride;

the molar ratio of the compound D to the 2- (2-nitroimidazol-1-yl) acetic acid is 1:1 to 1.1;

the molar ratio of the compound D to the 1-hydroxybenzotriazole is 1: 1.2 to 1.3;

the dosage ratio of the compound D to the dichloromethane is 1 mmol: 45-55 mL;

the molar ratio of the compound D to the 1-ethyl- (3-dimethylaminopropyl) carbonyldiimine hydrochloride is 1: 1.4 to 1.6.

10. Use of the supramolecular polymer in claim 1 for controlled release of fluorescent probes and drugs.

Technical Field

The invention relates to the technical field of high molecular compounds, in particular to a dual-response dipeptide supramolecular polymer and a preparation method and application thereof.

Background

Hypoxia is one of the prominent features of solid tumors, and tumor cell overgrowth and proliferation lead to failure of oxygen demand or reduced ability to transport oxygen to other sites, thereby causing a hypoxic environment inside the cell. The hypoxic environment is closely related to the growth, metastasis, drug resistance and the like of tumors. And due to the special physiochemical response to the outside, the advantages of biocompatibility, biodegradability and easy regulation and control through outside stimulation of the polypeptide are combined, and the like, the hypoxic response group (such as nitroimidazole, azobenzene and 4-nitrobenzyl ester) is introduced into the polypeptide structure to prepare the hypoxic response self-assembly polypeptide for the treatment and diagnosis of the targeted tumor, so that people are more and more concerned. However, when assembling, the polypeptide chain is generally long, and a solid-phase synthesis method is generally adopted, which has the disadvantages of small synthesis dosage, long separation and purification period and high synthesis cost.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provides a dual-response dipeptide supramolecular polymer and a preparation method and application thereof.

In order to achieve the above object, the present invention provides the following technical solutions:

a dual-response dipeptide supramolecular polymer is obtained by self-assembling dual-response dipeptide supramolecular monomers in water;

the mass concentration of the dipeptide supramolecular polymer is 0.05-2 mg/mL;

the dual-response dipeptide supramolecular monomer has a structure shown in a formula 1:

r is

R' is hydrogen, methyl or isopropyl;

x is methyl, ethyl or

The invention provides a monomer for preparing a dual-response dipeptide supramolecular polymer, which has a structure shown in a formula 1:

r is

R' is hydrogen, methyl or isopropyl;

x is methyl, ethyl or

The invention also provides a preparation method of the supramolecular monomer, which comprises the following steps:

(1) mixing tryptophan, 1-hydroxybenzotriazole, glycine methyl ester hydrochloride, dichloromethane, N-diisopropylethylamine and 1-ethyl- (3-dimethylaminopropyl) carbonyl diimine hydrochloride for condensation reaction to obtain a compound A;

(2) mixing the compound A, hydrated lithium hydroxide and a methanol aqueous solution, and carrying out substitution reaction to obtain a compound B;

(3) mixing the compound B, dendritic alkoxy ether, dichloromethane, 4-dimethylaminopyridine and 1-ethyl- (3-dimethylaminopropyl) carbonyl diimine hydrochloride, and carrying out esterification reaction to obtain a compound C;

(4) mixing the compound C, dichloromethane and trifluoroacetic acid, and carrying out substitution reaction to obtain a compound D;

(5) and (2) under an alkaline condition, mixing the compound D, the monomer and the reactant, and carrying out amidation reaction to obtain the dual-response dipeptide supramolecular monomer.

Preferably, the tryptophan in the step (1) is Boc-L-tryptophan;

the molar ratio of tryptophan to 1-hydroxybenzotriazole to glycine methyl ester hydrochloride is 0.8-1.2: 1-1.4: 0.9 to 1.3;

the molar ratio of the tryptophan to the N, N-diisopropylethylamine is 1: 2 to 2.4;

the molar ratio of tryptophan to 1-ethyl- (3-dimethylaminopropyl) carbonyldiimine hydrochloride is 1: 1.2 to 1.4;

the dosage ratio of the tryptophan to the dichloromethane is 1 mmol: 3-10 mL;

the temperature of the condensation reaction in the step (1) is 20-30 ℃, and the time of the condensation reaction is 10-12 h.

Preferably, the volume fraction of methanol in the methanol aqueous solution in the step (2) is 30-40%;

the molar ratio of the compound A to the hydrated lithium hydroxide is 1: 2-2.2;

the dosage ratio of the compound A to the methanol aqueous solution is 1 mmol: 5-10 g;

the temperature of the substitution reaction in the step (2) is 20-30 ℃, and the time of the substitution reaction is 2-3 h.

Preferably, the molar ratio of the dendritic alkoxylated alkoxy ether to the compound B in step (3) is 1:1.3 to 1.5;

the dosage ratio of the compound B to dichloromethane is 1 mmol: 10-20 mL;

the molar ratio of the compound B to the 4-dimethylaminopyridine is 1: 0.3 to 0.5;

the molar ratio of the compound B to the 1-ethyl- (3-dimethylaminopropyl) carbonyldiimine hydrochloride is 1: 1.2 to 1.4;

the temperature of the esterification reaction in the step (3) is 20-30 ℃, and the time of the esterification reaction is 12-14 h.

Preferably, the amount ratio of the compound C to the dichloromethane in the step (4) is 1 mmol: 7-13 mL;

the molar ratio of the compound C to the trifluoroacetic acid is 1: 20 to 22;

the temperature of the substitution reaction in the step (4) is 20-30 ℃, and the time of the substitution reaction is 2.5-3.5 h.

Preferably, the pH value of the alkaline condition in the step (5) is 9-10;

the monomer is p-nitro benzyl chloroformate or 2- (2-nitroimidazole-1-yl) acetic acid;

the temperature of the amidation reaction in the step (5) is 20-30 ℃, and the time of the amidation reaction is 10-14 h.

Preferably, when the monomer is benzyl p-nitrochloroformate, the reactants comprise dichloromethane, and the ratio of the amount of the compound D to the amount of dichloromethane is 1 mmol: 35-45 mL;

the molar ratio of the compound D to the p-nitro benzyl chloroformate is 1: 1.1 to 1.2;

when the monomer is 2- (2-nitroimidazol-1-yl) acetic acid, the reactants comprise dichloromethane, 1-hydroxybenzotriazole and 1-ethyl- (3-dimethylaminopropyl) carbodiimides hydrochloride;

the molar ratio of the compound D to the 2- (2-nitroimidazol-1-yl) acetic acid is 1:1 to 1.1;

the molar ratio of the compound D to the 1-hydroxybenzotriazole is 1: 1.2 to 1.3;

the dosage ratio of the compound D to the dichloromethane is 1 mmol: 45-55 mL;

the molar ratio of the compound D to the 1-ethyl- (3-dimethylaminopropyl) carbonyldiimine hydrochloride is 1: 1.4 to 1.6.

The invention also provides application of the supramolecular polymer in fluorescent probes and controlled release of drugs.

The invention provides a double-response dipeptide supramolecular polymer, which is formed by adopting a liquid phase synthesis method, modifying hypoxic response element p-nitro benzyl chloroformate or 2- (2-nitroimidazole-1-yl) acetic acid at an N end through tryptophan glycine dipeptide, modifying temperature-sensitive element dendritic alkoxy ether at a C end, and performing self-assembly in an aqueous solution. The supramolecular polymer is simple to prepare, the fluorescence intensity is greatly enhanced under the hypoxic condition through the tryptophan fluorescence characteristic, meanwhile, the polymer can coat the medicine, the release of the medicine is realized by the disassembly of the polymer under the hypoxic condition, and a research basis is provided for the research and development of a carrier of a novel nano medicine.

Drawings

FIG. 1 is a NMR spectrum of BocWG-OMe in example 1;

FIG. 2 is a NMR spectrum of BocWG-OH in example 1;

FIG. 3 is BocWG-G of example 1₁The nuclear magnetic resonance hydrogen spectrum of (a);

FIG. 4 shows the dual response dipeptide supramolecular monomer NA-WG-G prepared in example 1₁The nuclear magnetic resonance hydrogen spectrum of (a);

FIG. 5 shows the dual response dipeptide supramolecular monomer NA-WG-G prepared in example 1₁High resolution mass spectrograms of (a);

fig. 6 is a graph of the critical assembly concentration of the dual response dipeptide supramolecular polymer prepared in example 1:

FIG. 7 is a temperature-sensitive reversible diagram of the dual response dipeptide supramolecular polymer in example 1;

FIG. 8 is a temperature-sensitive graph of the dual response dipeptide supramolecular polymer in example 1;

FIG. 9 is a graph showing the change of fluorescence intensity with time after the reduction of the dual response dipeptide supramolecular polymer in example 1;

FIG. 10 is a graph showing the change of the peak fluorescence intensity of the dual-response dipeptide supramolecular polymer in example 1 with respect to time;

FIG. 11 is a graph of the coating effect of the dual response dipeptide supramolecular polymer in example 1 on naproxen under hypoxic conditions;

FIG. 12 is the dual response dipeptide supramolecular monomer NI-WG-G prepared in example 2₁The nuclear magnetic resonance hydrogen spectrum of (a);

FIG. 13 is a temperature-sensitive graph of the dual response dipeptide supramolecular polymer in example 2;

FIG. 14 is a graph of fluorescence intensity versus time after reduction of the dual response dipeptide supramolecular polymer in example 2;

FIG. 15 is a graph showing the peak fluorescence intensity versus time for the dual response dipeptide supramolecular polymers in example 2;

fig. 16 is a graph of the effect of dual response dipeptide supramolecular polymers on naproxen encapsulation under hypoxic conditions in example 2.

Detailed Description

The invention provides a dual-response dipeptide supramolecular polymer, which is obtained by self-assembling dual-response dipeptide supramolecular monomers in water;

the mass concentration of the dipeptide supramolecular polymer is 0.05-2 mg/mL;

the dual-response dipeptide supramolecular monomer has a structure shown in a formula 1:

r is

R' is hydrogen, methyl or isopropyl;

x is methyl, ethyl or

In the invention, the dual-response dipeptide supramolecular monomer is prepared into an aqueous solution and then stands still, and the dual-response dipeptide supramolecular polymer is obtained under the action of water through the self-assembly; the mass concentration of the dipeptide supramolecular polymer is 0.05-2 mg/mL, preferably 0.1-1 mg/mL, and more preferably 0.4-0.6 mg/mL; the standing time is preferably 8-24 h, more preferably 12-20 h, and even more preferably 14-18 h.

The invention provides a monomer for preparing a dual-response dipeptide supramolecular polymer, which has a structure shown in a formula 1:

r is

R' is hydrogen, methyl or isopropyl;

x is methyl, ethyl or

The invention also provides a preparation method of the supramolecular monomer, which comprises the following steps:

(1) mixing tryptophan, 1-hydroxybenzotriazole, glycine methyl ester hydrochloride, dichloromethane, N-diisopropylethylamine and 1-ethyl- (3-dimethylaminopropyl) carbonyl diimine hydrochloride for condensation reaction to obtain a compound A;

(2) mixing the compound A, hydrated lithium hydroxide and a methanol aqueous solution, and carrying out substitution reaction to obtain a compound B;

(3) mixing the compound B, dendritic alkoxy ether, dichloromethane, 4-dimethylaminopyridine and 1-ethyl- (3-dimethylaminopropyl) carbonyl diimine hydrochloride, and carrying out esterification reaction to obtain a compound C;

(4) mixing the compound C, dichloromethane and trifluoroacetic acid, and carrying out substitution reaction to obtain a compound D;

(5) and (2) under an alkaline condition, mixing the compound D, the monomer and the reactant, and carrying out amidation reaction to obtain the dual-response dipeptide supramolecular monomer.

In the present invention, the tryptophan in the step (1) is preferably Boc-L-tryptophan.

In the invention, the molar ratio of tryptophan, 1-hydroxybenzotriazole and glycine methyl ester hydrochloride is preferably 0.8-1.2: 1-1.4: 0.9 to 1.3, more preferably 0.9 to 1.1: 1.1-1.3: 1.0 to 1.2, more preferably 0.95 to 1.05: 1.15-1.25: 1.05 to 1.15.

In the present invention, the molar ratio of tryptophan to N, N-diisopropylethylamine is preferably 1: 2 to 2.4, and more preferably 1: 2.1 to 2.3, more preferably 1: 2.15 to 2.25.

In the present invention, the molar ratio of tryptophan to 1-ethyl- (3-dimethylaminopropyl) carbonyldiimine hydrochloride is preferably 1: 1.2 to 1.4, and more preferably 1: 1.24-1.36, more preferably 1: 1.28 to 1.32.

In the present invention, the ratio of the amounts of tryptophan and dichloromethane is preferably 1 mmol: 3-10 mL, more preferably 1 mmol: 4-9 mL, more preferably 1 mmol: 5-8 mL.

In the invention, tryptophan, 1-hydroxybenzotriazole, glycine methyl ester hydrochloride and dichloromethane are mixed in an inert atmosphere, and then N, N-diisopropylethylamine is added for preliminary reaction to obtain a reaction system. The temperature of the primary reaction is preferably-3 ℃, more preferably-2 ℃, and more preferably-1 ℃; the time of the primary reaction is preferably 15-25 min, more preferably 16-24 min, and even more preferably 18-22 min; the preliminary reaction is carried out under the condition of stirring, and the rotation speed of the stirring is preferably 300-400 rpm, more preferably 320-380 rpm, and even more preferably 340-360 rpm.

In the invention, after the primary reaction is finished, the reaction system and 1-ethyl- (3-dimethylaminopropyl) carbodiimide hydrochloride are mixed in an inert atmosphere to carry out a secondary reaction, so as to obtain a mixed system. The temperature of the secondary reaction is preferably-3 ℃, more preferably-2 ℃, and more preferably-1 ℃; the time of the secondary reaction is preferably 15-25 min, more preferably 16-24 min, and more preferably 18-22 min, the secondary reaction is carried out under the condition of stirring, and the rotation speed of the stirring is preferably 300-400 rpm, more preferably 320-380 rpm, and more preferably 340-360 rpm. After the secondary reaction, the next condensation reaction is carried out.

In the invention, the condensation reaction temperature in the step (1) is preferably 20-30 ℃, more preferably 22-28 ℃, and more preferably 24-26 ℃; the time of the condensation reaction is preferably 10 to 12 hours, more preferably 10.5 to 11.5 hours, and even more preferably 10.8 to 11.2 hours.

In the invention, TLC detection is carried out on the reaction solution obtained after the condensation reaction in the step (1) is finished; the mobile phase for TLC detection preferably comprises petroleum ether and ethyl acetate, and the volume ratio of the petroleum ether to the ethyl acetate is preferably 1.5-2.5: 2.5 to 3.5, and more preferably 1.6 to 2.4: 2.6 to 3.4, more preferably 1.8 to 2.2: 2.8 to 3.2; after the detection reaction is completed, extraction is carried out, wherein the extraction is potassium bisulfate extraction and dichloromethane extraction which are sequentially carried out, and the mass concentration of a potassium bisulfate solution in the potassium bisulfate extraction is preferably 8-12%, more preferably 9-11%, and more preferably 9.5-10.5%; the volume ratio of the reaction solution to the potassium hydrogen sulfate solution is preferably 1: 1.2 to 1.5, and more preferably 1:1.3 to 1.4, more preferably 1: 1.34 to 1.36; the number of extraction times of dichloromethane is preferably 2-3, and the volume ratio of the reaction solution to dichloromethane is preferably 1: 1.2 to 1.5, and more preferably 1:1.3 to 1.4, more preferably 1: 1.34-1.36. Combining organic phases obtained by two extraction modes, and drying by adopting anhydrous sodium sulfate, wherein the dosage ratio of the organic phase to the anhydrous sodium sulfate is preferably 10-15 mL: 1g, more preferably 11 to 14 mL: 1g, more preferably 12-13 mL: 1g of a compound; the drying time is preferably 30-40 min, more preferably 32-38 min, and still more preferably 34-36 min.

In the present invention, after the completion of the drying, column chromatography purification is performed. The mobile phase for column chromatographic purification preferably comprises petroleum ether and ethyl acetate, and the volume ratio of the petroleum ether to the ethyl acetate is preferably 1.5-2.5: 2.5 to 3.5, and more preferably 1.6 to 2.4: 2.6 to 3.4, more preferably 1.8 to 2.2: 2.8 to 3.2. And purifying by column chromatography to obtain a white solid, namely the compound A.

In the present invention, the reaction of the step (1) is as follows:

in the present invention, the volume fraction of methanol in the methanol aqueous solution in the step (2) is preferably 30 to 40%, more preferably 32 to 38%, and even more preferably 34 to 36%.

In the present invention, the molar ratio of the compound a to the hydrated lithium hydroxide is preferably 1: 2 to 2.2, and more preferably 1: 2.05-2.15, more preferably 1: 2.08 to 2.12.

In the present invention, the ratio of the amount of the compound a to the aqueous methanol solution is preferably 1 mmol: 5-10 g, more preferably 1 mmol: 6-9 g, more preferably 1 mmol: 7-8 g.

In the invention, the temperature of the substitution reaction in the step (2) is preferably 20-30 ℃, more preferably 22-28 ℃, and more preferably 24-26 ℃; the time of the substitution reaction is preferably 2 to 3 hours, more preferably 2.2 to 2.8 hours, and even more preferably 2.4 to 2.6 hours.

In the invention, a mixed system is obtained after the substitution reaction in the step (2), and the mixed system is subjected to TLC detection; the mobile phase for TLC detection preferably comprises dichloromethane and methanol, and the volume ratio of the dichloromethane to the methanol is preferably 25-35: 1, more preferably 26 to 34: 1, more preferably 28 to 32: 1. TLC was checked to ensure that the substitution was complete.

In the invention, the TLC detection is preferably carried out after the TLC detection is finished, the drying temperature is preferably 80-140 ℃, more preferably 90-130 ℃, and more preferably 100-120 ℃, the drying is to remove methanol in the system, and the pH value is adjusted after the drying is carried out to constant weight. The pH value of the pH value is preferably 2-4, and more preferably 3; the reagent for adjusting the pH value is preferably a potassium hydrogen sulfate solution, and the mass fraction of the potassium hydrogen sulfate solution is preferably 8-12%, more preferably 9-11%, and even more preferably 9.5-10.5%.

In the invention, ethyl acetate is adopted for extraction after the pH value is adjusted, and the extraction mode is the extraction method commonly used in the field. Extraction showed no uv absorption of the aqueous phase on GF254 thin layer plates and no ninhydrin colour reaction and extraction was stopped. Collecting an extracted organic phase, and drying the organic phase by using anhydrous sodium sulfate, wherein the preferable dosage ratio of the organic phase to the anhydrous sodium sulfate is 5-10 mL: 1g, more preferably 6-9 mL: 1g, more preferably 7-8 mL: 1g, dried to constant weight. And after drying, sequentially carrying out filtration and secondary drying, wherein the temperature of the secondary drying is preferably 80-140 ℃, more preferably 90-130 ℃, and more preferably 100-120 ℃. And drying for the second time to constant weight to obtain a white solid, namely the compound B.

In the present invention, the reaction of the step (2) is as follows:

in the present invention, the molar ratio of the dendritic alkoxylated ether and the compound B in the step (3) is preferably 1:1.3 to 1.5, and more preferably 1: 1.35-1.45, more preferably 1: 1.38 to 1.42.

In the present invention, the amount ratio of the compound B and dichloromethane is preferably 1 mmol: 10 to 20mL, more preferably 1 mmol: 12-18 mL, more preferably 1 mmol: 14-16 mL.

In the present invention, the molar ratio of the compound B and 4-dimethylaminopyridine is preferably 1: 0.3 to 0.5, and more preferably 1: 0.35 to 0.45, more preferably 1: 0.38 to 0.42.

In the present invention, the molar ratio of the compound B and 1-ethyl- (3-dimethylaminopropyl) carbonyldiimine hydrochloride is preferably 1: 1.2 to 1.4, and more preferably 1: 1.25 to 1.35, more preferably 1: 1.28 to 1.32.

In the present invention, compound B, dendronized alkoxy ether, 4-dimethylaminopyridine and dichloromethane are mixed under an inert atmosphere to carry out a preliminary reaction. The temperature of the primary reaction is preferably-3 ℃, more preferably-2 ℃, and more preferably-1 ℃; the time of the primary reaction is preferably 15-25 min, more preferably 16-24 min, and even more preferably 18-22 min. And obtaining a reaction system after the preliminary reaction is finished.

In the present invention, the reaction system and 1-ethyl- (3-dimethylaminopropyl) carbodiimide hydrochloride are mixed under an inert atmosphere to carry out a secondary reaction. The temperature of the secondary reaction is preferably-3 ℃, more preferably-2 ℃, and more preferably-1 ℃; the time of the secondary reaction is preferably 15-25 min, more preferably 16-24 min, and even more preferably 18-22 min. After the secondary reaction is finished, the next esterification reaction is carried out.

In the invention, the temperature of the esterification reaction in the step (3) is preferably 20-30 ℃, more preferably 22-28 ℃, and more preferably 24-26 ℃; the esterification reaction time is preferably 12-14 h, more preferably 12.5-13.5 h, and even more preferably 12.8-13.2 h.

In the invention, a mixed system is obtained after the esterification reaction in the step (3), and the mixed system is subjected to TLC detection; the mobile phase for TLC detection preferably comprises dichloromethane and methanol, and the volume ratio of the dichloromethane to the methanol is preferably 15-25: 1, more preferably 16 to 24: 1, more preferably 18 to 32: 1. TLC detection was performed to ensure complete esterification.

In the present invention, after the TLC detection is finished, the mixed system is extracted, and the extraction reagent is preferably saturated aqueous sodium chloride solution. The volume ratio of the saturated sodium chloride aqueous solution to the mixed system is preferably 1: 1.2 to 1.5, and more preferably 1:1.3 to 1.4, more preferably 1: 1.34-1.36. The number of times of extraction is preferably 2-3. Collecting an extracted organic phase, and drying the organic phase by using anhydrous sodium sulfate, wherein the preferable dosage ratio of the organic phase to the anhydrous sodium sulfate is 5-10 mL: 1g, more preferably 6-9 mL: 1g, more preferably 7-8 mL: 1g, dried to constant weight. After drying, filtration and column chromatography purification are carried out in sequence.

In the present invention, column chromatography purification is performed after filtration. The mobile phase for column chromatography purification preferably comprises dichloromethane and methanol, and the volume ratio of the dichloromethane to the methanol is preferably 15-25: 1, more preferably 16 to 24: 1, more preferably 18 to 22: 1. and drying after column chromatography purification, wherein the drying temperature is preferably 70-80 ℃, more preferably 72-78 ℃, and more preferably 74-76 ℃. Drying until the solvent is completely volatilized to obtain a light yellow oily liquid, namely the compound C.

In the present invention, the reaction of the step (3) is as follows:

in the present invention, the ratio of the amount of the compound C and dichloromethane in the step (4) is preferably 1 mmol: 7-13 mL, more preferably 1 mmol: 8-12 mL, more preferably 1 mmol: 9-11 mL.

In the present invention, the molar ratio of the compound C and trifluoroacetic acid is preferably 1: 20 to 22, and more preferably 1: 20.5 to 21.5, more preferably 1: 20.8 to 21.2.

In the invention, after the compound C and dichloromethane are mixed, trifluoroacetic acid is dripped into a reaction system for preliminary reaction. The dropping rate is preferably 0.5-1 drop/second. The temperature of the primary reaction is preferably-3 ℃, more preferably-2 ℃, and more preferably-1 ℃; the time of the primary reaction is preferably 10-20 min, more preferably 12-18 min, and even more preferably 14-16 min. After the primary reaction is finished, the next substitution reaction is carried out.

In the invention, the temperature of the substitution reaction in the step (4) is preferably 20-30 ℃, more preferably 22-28 ℃, and more preferably 24-26 ℃; the time of the substitution reaction is preferably 2.5 to 3.5 hours, more preferably 2.6 to 3.4 hours, and even more preferably 2.8 to 3.2 hours.

In the invention, TLC detection is carried out after the substitution reaction in the step (4) is finished; the mobile phase for TLC detection preferably comprises dichloromethane and methanol, and the volume ratio of the dichloromethane to the methanol is preferably 15-25: 1, more preferably 16 to 24: 1, more preferably 18 to 32: 1. TLC was checked to ensure that the substitution was complete.

In the invention, after TLC detection is finished, methanol is added into a reaction system for quenching, wherein the volume of the methanol is preferably 20-30 mL, more preferably 22-28 mL, and more preferably 24-26 mL. And adding methanol, and then stirring, wherein the rotation speed of stirring is preferably 300-400 rpm, more preferably 320-380 rpm, and more preferably 340-360 rpm, and the stirring time is preferably 20-40 min, more preferably 24-36 min, and more preferably 28-32 min. After the stirring was completed, the methanol was evaporated to dryness by a method commonly used in the art.

In the invention, after methanol is evaporated to dryness, the next post-treatment is carried out, wherein the post-treatment is to add dichloromethane and evaporate the methanol to dryness sequentially; the volume of the dichloromethane is preferably 10-15 mL, more preferably 11-14 mL, and even more preferably 12-13 mL; after addition of dichloromethane, the dichloromethane is evaporated to dryness by methods customary in the art. The post-treatment is preferably performed for 3-4 times, and the compound D is obtained.

In the present invention, the reaction of the step (4) is as follows:

in the present invention, the pH value of the alkaline condition in the step (5) is preferably 9 to 10, more preferably 9.2 to 9.8, and still more preferably 9.4 to 9.6.

In the invention, the reagent for adjusting the pH value is preferably N, N-diisopropylethylamine.

In the present invention, the monomer is preferably benzyl p-nitrochloroformate or 2- (2-nitroimidazol-1-yl) acetic acid.

In the invention, the temperature of the amidation reaction in the step (5) is preferably 20-30 ℃, more preferably 22-28 ℃, and even more preferably 24-26 ℃; the time of the amidation reaction is preferably 10 to 14 hours, more preferably 11 to 13 hours, and even more preferably 11.5 to 12.5 hours.

In the present invention, when the monomer is benzyl p-nitrochloroformate, the reactant comprises dichloromethane, and the ratio of the amount of the compound D to the dichloromethane is preferably 1 mmol: 35-45 mL, more preferably 1 mmol: 36-44 mL, more preferably 1 mmol: 38-42 mL.

In the invention, after the compound D and dichloromethane are mixed, the pH of the system is adjusted to be alkaline by using N, N-diisopropylethylamine, and then p-nitro benzyl chloroformate is dissolved in dichloromethane and is dripped into the system, wherein the dosage ratio of the p-nitro benzyl chloroformate to the dichloromethane is preferably 1 mmol: 9-10 mL, more preferably 1 g: 9.2-9.8 mL, more preferably 1 g: 9.4-9.6 mL; the dropping rate is preferably 0.5-1 drop/second. After the dropwise addition, the next amidation reaction is carried out.

In the present invention, the molar ratio of compound D to benzyl p-nitrochloroformate is preferably 1: 1.1 to 1.2, and more preferably 1: 1.12 to 1.18, more preferably 1: 1.14 to 1.16.

In the invention, TLC detection is carried out after the amidation reaction is finished; the mobile phase for TLC detection preferably comprises dichloromethane and methanol, and the volume ratio of the dichloromethane to the methanol is preferably 15-25: 1, more preferably 16 to 24: 1, more preferably 18 to 32: 1. TLC was checked to ensure that the substitution was complete.

In the invention, after TLC detection is finished, the reaction solution is washed, and the washing is potassium bisulfate washing and sodium chloride washing which are sequentially carried out; the mass fraction of the potassium bisulfate solution in the potassium bisulfate washing is preferably 8-12%, more preferably 9-11%, and even more preferably 9.5-10.5%; and the sodium chloride solution in the sodium chloride washing is a saturated sodium chloride solution. The washing is carried out by methods commonly used in the art. And after washing, drying the reaction solution by adopting anhydrous sodium sulfate, wherein the use ratio of the reaction solution to the anhydrous sodium sulfate is preferably 10-15 mL: 1g, more preferably 11 to 14 mL: 1g, more preferably 12-13 mL: 1g of a compound; drying to constant weight. After drying, filtration and column chromatography purification are carried out in sequence.

In the present invention, column chromatography purification is performed after filtration. The mobile phase for column chromatography purification preferably comprises dichloromethane and methanol, and the volume ratio of the dichloromethane to the methanol is preferably 25-35: 1, more preferably 26 to 34: 1, more preferably 28 to 32: 1. purifying by column chromatography, and drying to remove solvent by evaporation by conventional method; and evaporating to dryness to obtain a light yellow oily liquid, namely the final product dual-response dipeptide supramolecular monomer.

In the present invention, when the monomer is benzyl p-nitrochloroformate, the reaction of step (5) is as follows:

in the present invention, when the monomer is 2- (2-nitroimidazol-1-yl) acetic acid, the reactants preferably comprise dichloromethane, 1-hydroxybenzotriazole and 1-ethyl- (3-dimethylaminopropyl) carbonyldiimine hydrochloride.

In the present invention, the molar ratio of the compound D and 2- (2-nitroimidazol-1-yl) acetic acid is preferably 1:1 to 1.1, and more preferably 1: 1.02 to 1.08, more preferably 1: 1.04 to 1.06.

In the present invention, the molar ratio of the compound D and 1-hydroxybenzotriazole is preferably 1: 1.2 to 1.3, and more preferably 1: 1.22 to 1.28, more preferably 1: 1.24-1.26.

In the present invention, the amount ratio of the compound D and dichloromethane is preferably 1 mmol: 45-55 mL, more preferably 1 mmol: 46-54 mL, more preferably 1 mmol: 48-52 mL.

In the present invention, the molar ratio of the compound D and 1-ethyl- (3-dimethylaminopropyl) carbonyldiimine hydrochloride is preferably 1: 1.4 to 1.6, and more preferably 1: 1.44-1.56, more preferably 1: 1.48 to 1.52.

In the invention, compound D, 2- (2-nitroimidazol-1-yl) acetic acid, 1-hydroxybenzotriazole and dichloromethane are mixed, and N, N-diisopropylethylamine is used for adjusting the pH of the system to be alkaline; and carrying out primary reaction in an inert atmosphere to obtain a reaction system. The temperature of the primary reaction is preferably-3 ℃, more preferably-2 ℃, and more preferably-1 ℃; the time of the primary reaction is preferably 25-35 min, more preferably 26-34 min, and even more preferably 28-32 min; the preliminary reaction is carried out under the condition of stirring, and the rotation speed of the stirring is preferably 300-400 rpm, more preferably 320-380 rpm, and even more preferably 340-360 rpm.

In the present invention, after the completion of the primary reaction, 1-ethyl- (3-dimethylaminopropyl) carbonyldiimine hydrochloride is added to the reaction system, and a secondary reaction is carried out in an inert atmosphere. The temperature of the secondary reaction is preferably-3 ℃, more preferably-2 ℃, and more preferably-1 ℃; the time of the secondary reaction is preferably 25-35 min, more preferably 26-34 min, and even more preferably 28-32 min; the secondary reaction is carried out under the condition of stirring, and the rotation speed of the stirring is preferably 300-400 rpm, more preferably 320-380 rpm, and even more preferably 340-360 rpm.

In the invention, amidation reaction is carried out after the secondary reaction is finished, a primary product is obtained after the amidation reaction is finished, and the primary product is sequentially washed, extracted, dried, purified and distilled under reduced pressure. The washing reagent is preferably a potassium hydrogen sulfate solution, and the mass fraction of the potassium hydrogen sulfate solution is preferably 8-12%, more preferably 9-11%, and even more preferably 9.5-10.5%. The volume ratio of the potassium hydrogen sulfate solution to the primary product is preferably 1:1 to 1.5, and more preferably 1: 1.1 to 1.4, more preferably 1: 1.2 to 1.3. The reagent for extraction is preferably dichloromethane, and the volume ratio of the dichloromethane to the primary product is preferably 1:1 to 1.5, and more preferably 1: 1.1 to 1.4, more preferably 1: 1.2 to 1.3; the dried reagent is preferably anhydrous sodium sulfate, and the dosage ratio of the primary product to the anhydrous sodium sulfate is preferably 10-15 mL: 1g, more preferably 11 to 14 mL: 1g, more preferably 12-13 mL: 1g of the total weight of the composition. The purification is preferably a column chromatography purification. The mobile phase for column chromatography purification preferably comprises dichloromethane and methanol, and the volume ratio of the dichloromethane to the methanol is preferably 15-25: 1, more preferably 16 to 24: 1, more preferably 18 to 22: 1. carrying out reduced pressure distillation after column chromatography purification, and carrying out reduced pressure distillation by adopting a method commonly used in the field to obtain light yellow oily liquid, namely the dual-response dipeptide supramolecular monomer.

In the present invention, when the monomer is 2- (2-nitroimidazol-1-yl) acetic acid, the reaction of the step (5) is as follows:

the invention also provides application of the supramolecular polymer in fluorescent probes and controlled release of drugs.

The technical solutions provided by the present invention are described in detail below with reference to examples, but they should not be construed as limiting the scope of the present invention.

Example 1

Mixing 1mmol of Boc-L-tryptophan, 1.2mmol of 1-hydroxybenzotriazole, 1.1mmol of glycine methyl ester hydrochloride and 10mL of dichloromethane in a nitrogen atmosphere, then adding 2mmol of N, N-diisopropylethylamine, carrying out primary reaction for 20min at 0 ℃ and 350rpm to obtain a reaction system, mixing the reaction system with 1.2mmol of 1-ethyl- (3-dimethylaminopropyl) carbonyl diimine hydrochloride, replacing nitrogen, and carrying out secondary reaction for 20min at 0 ℃ and 350 rpm; after the secondary reaction is finished, carrying out condensation reaction for 11h at 25 ℃; and (3) performing TLC detection after the reaction is finished, wherein the volume ratio of petroleum ether to ethyl acetate is 2: and 3, extracting by using a 10% potassium hydrogen sulfate solution, wherein the volume ratio of the reaction solution to the potassium hydrogen sulfate solution is 1: 1.5; and then extracted 3 times with dichloromethane, the volume ratio of the reaction solution to dichloromethane being 1: 1.3; combining the organic phases obtained by extraction, wherein the total volume is 13mL, and drying for 30min by using 1g of anhydrous sodium sulfate; and after drying, filtering, carrying out column chromatography purification by using silica gel to carry out sample loading, wherein the volume ratio of petroleum ether to ethyl acetate in the column chromatography is 2: 3, Compound A was obtained as a white solid, noted BocWG-OMe, in 94.8% yield. Dissolving BocWG-OMe in d₆in-DMSO, NMR detection was carried out, as shown in FIG. 1.

Dissolving 1mmol of prepared BocWG-OMe in 9g of methanol aqueous solution, wherein the volume fraction of methanol in the methanol aqueous solution is 35%, adding 2mmol of hydrated lithium hydroxide after dissolving, and reacting at 25 ℃ for 2 h; completing the substitution reaction to obtain a mixed system, and performing TLC detection, wherein the volume ratio of dichloromethane to methanol is30: 1; drying at 110 deg.C to remove methanol, adjusting pH of the dried mixed system to 3 with 10% potassium hydrogen sulfate solution, extracting with ethyl acetate for 5 times until the water phase has no ultraviolet absorption and no ninhydrin color reaction on GF254 thin layer plate, and stopping extraction. Collecting an organic phase obtained by extraction, and drying the organic phase by using anhydrous sodium sulfate, wherein the ratio of the organic phase to the anhydrous sodium sulfate is 10 mL: 1g, drying to constant weight; filtration and secondary drying after drying, followed by evaporation of the solvent to dryness at 110 ℃ gave compound B as a white solid, noted BocWG-OH, in 98.0% yield. Dissolving BocWG-OH in d₆in-DMSO, NMR detection was carried out, as shown in FIG. 2.

1.3mmol of prepared BocWG-OH and 1mmol of dendritic alkoxy ether G₁dissolving-OH in 25mL of dichloromethane, adding 0.52mmol of 4-dimethylaminopyridine after complete dissolution, and reacting for 20min at 0 ℃ under the condition of nitrogen to complete a primary reaction; then 1.82mmol of 1-ethyl- (3-dimethylaminopropyl) carbodiimide hydrochloride is added to replace nitrogen, and the mixture reacts for 20min at the temperature of 0 ℃ to complete the secondary reaction; then carrying out esterification reaction for 12h at the temperature of 25 ℃ to finish the esterification reaction. After the reaction is finished, TLC detection is carried out, and the volume ratio of dichloromethane to methanol is 20: 1, according to the volume ratio of a saturated sodium chloride aqueous solution to a mixed system of 1:1.3, extracting for 3 times, and collecting an organic phase; the dosage ratio of the organic phase to the anhydrous sodium sulfate is 10 mL: 1g, drying to constant weight; filtering after drying; carrying out column chromatography purification by using silica gel, wherein the volume ratio of dichloromethane to methanol in the column chromatography is 20: 1, evaporating the solvent to dryness at 75 ℃ to give Compound C as a pale yellow oily liquid, noted BocWG-G₁The yield was 65.59%. Mixing BocWG-G₁Dissolved in d₆in-DMSO, NMR detection was performed, as shown in FIG. 3.

1mmol of prepared BocWG-G was taken₁Dissolving in 10mL of dichloromethane, dropwise adding 20mol of trifluoroacetic acid into a reaction system at the temperature of 0 ℃ at the rate of 1 drop/second, and reacting for 15min to complete the primary reaction after all the dropwise adding is finished; then the reaction is carried out for 2.5h at 25 ℃ to complete the substitution reaction; after the reaction is finished, TLC detection is carried out, and the volumes of dichloromethane and methanolThe ratio is 20: 1; then adding 25mL of methanol into the system to quench the reaction, and stirring for 30min at the rotating speed of 350 rpm; evaporating methanol and performing post-treatment; adding 10mL of dichloromethane into the system, and evaporating the dichloromethane to dryness to complete one-time post-treatment; after 3 post-treatments, compound D, recorded as TFA-WG-G, was obtained₁。

1mmol of the prepared TFA-WG-G was taken₁Dissolving in 40mL of dichloromethane, adjusting the pH value to 9 by using N, N-diisopropylethylamine, then dissolving 1.1mmol of p-nitro benzyl chloroformate in 10mL of dichloromethane, dropwise adding into the system at the speed of 1 drop/second, and reacting at 25 ℃ for 12 hours to complete amidation reaction to obtain 20mL of reaction liquid; after the reaction is finished, TLC detection is carried out, and the volume ratio of dichloromethane to methanol is 20: 1; sequentially washing by adopting 10 percent potassium bisulfate and saturated sodium chloride solution; after washing, drying the mixture to constant weight by using 2g of anhydrous sodium sulfate; filtering after drying; carrying out column chromatography purification by using silica gel, wherein the volume ratio of dichloromethane to methanol in the column chromatography is 30: 1, evaporating the solvent to dryness to obtain a faint yellow oily liquid dual-response dipeptide supramolecular monomer which is marked as NA-WG-G₁The yield was 41.78%, and NA-WG-G was added₁Dissolved in d₆in-DMSO, NMR detection was carried out, as shown in FIG. 4. The molecules were further confirmed by high resolution mass spectrometry, as shown in fig. 5.

2mg of the dipeptide supramolecular monomer NA-WG-G prepared in the example₁Dissolving in 4mL deionized water, dissolving by using a vortex instrument, standing for 12h, and preparing the dual-response dipeptide supramolecular polymer.

Determining critical micelle concentration (CAC) of dipeptide supramolecular monomer by fluorescence and fluorescence spectroscopy, and configuring NA-WG-G of 0.5 mg/mL-1₁The solution was added to 1300. mu.L of water with a gradient of 20. mu.L each time. 284nm is selected as the excitation wavelength, after each addition and uniform mixing, the corresponding fluorescence spectrum is obtained by monitoring the fluorescence intensity of 290-500nm, and the fluorescence intensity at the emission wavelength of 350nm and the concentration of the dipeptide solution form a good functional relationship. CAC can be determined by where the linear relationship between concentration and fluorescence intensity changes, and the slope of two fitted lines changes at a concentration of 45. mu.M, sinceThis putative compound NA-WG-G₁The CAC of (a) is about 45. mu.M, as shown in FIG. 6.

One end of the supermolecule monomer is a dendritic alkoxy ether structure, and the supermolecule polymer is formed by assembling under the action of non-covalent force. When the temperature rises and exceeds the lowest critical phase transition temperature (LCST), the alkoxy ether chains are gathered and collapsed to form a hydrophobic microenvironment and are assembled to form a large assembly, so that the solution is turbid, and when the temperature returns to room temperature, the turbid solution becomes clear again, which proves the reversibility of the phase transition process of temperature rise, as shown in figure 7. Adopting variable temperature ultraviolet visible spectrum to NA-WG-G₁The supramolecular polymer was studied and the results are shown in figure 8. 0.5 mg/mL in the temperature range of 20-55 DEG C^-1NA-WG-G of₁The solution will show a decreasing light transmittance with increasing temperature, and when the temperature is decreased, the light transmittance will be restored.

Subjecting NA-WG-G₁After the reducing agent is added into the solution, the fluorescence change of the solution within 2.5h is observed, as shown in fig. 9, the fluorescence is quenched just after the reducing agent is added, and the wavelength is red-shifted, which may be caused by the fact that the supramolecular assembly is disassembled due to the addition of the reducing agent, the molecules are dispersed and free in the solution, and the fluorescence of tryptophan is quenched due to the strong electron-withdrawing effect of the nitro groups in the molecules, so the fluorescence intensity is reduced; the fluorescence intensity gradually increases along with the time, the wavelength is red-shifted until the wavelength is stabilized after 2.5h, and the reason is that the NA-WG-G in the system₁The reduced ratio is gradually increased, the nitro group quenching the fluorescence is reduced, and an elimination reaction is carried out to recover the fluorescence. The peak value and the time of each time node are selected to be plotted to obtain a graph 10, the change trend of the light intensity along with the time can be seen from the graph, the fluorescence intensity is 10 times that of the fluorescence intensity when the fluorescence intensity is not reduced after the fluorescence intensity is stabilized, and the fluorescence change is obvious, so that the fluorescence probe has the potential of being used as a hypoxic fluorescence probe.

Investigation of NA-WG-G Using fluorescence Spectroscopy₁Coating of the drug naproxen (Nap). One end of the Nap molecule is carboxyl, so the Nap molecule is dissolved by alkaline aqueous solution; the drug molecule has a conjugated structure and can emit fluorescence, so that fluorescence spectroscopy can be adoptedThe coating of naproxen was observed photometrically. As shown in FIG. 11, the fluorescence intensity of the naproxen solution alone is stronger than that of Nap naproxen and NA-WG-G₁The mixed solution of (1), which indicates that part of Nap is replaced by NA-WG-G₁Coated, fluorescence quenching occurs; when NA-WG-G₁After being reduced, the hydrophobic groups of the molecules fall off, the supermolecular assembly is disassembled, the fluorescence intensity is greatly increased, and the coated drug molecules are released.

Example 2

Mixing 1.2mmol of Boc-L-tryptophan, 1mmol of 1-hydroxybenzotriazole, 1.3mmol of glycine methyl ester hydrochloride and 4mL of dichloromethane in a nitrogen atmosphere, adding 2.6mmol of N, N-diisopropylethylamine, carrying out primary reaction at 0 ℃ and 400rpm for 25min to obtain a reaction system, mixing the reaction system with 1.44mmol of 1-ethyl- (3-dimethylaminopropyl) carbodiimide hydrochloride, replacing nitrogen, and carrying out secondary reaction at 0 ℃ and 400rpm for 25 min; after the secondary reaction is finished, carrying out condensation reaction for 12h at 30 ℃; after the reaction is finished, TLC detection is carried out, and the volume ratio of petroleum ether to ethyl acetate is 2.5: 3.5, extracting by using a 10% potassium hydrogen sulfate solution, wherein the volume ratio of the reaction solution to the potassium hydrogen sulfate solution is 1: 1.3; and then extracted 3 times with dichloromethane, the volume ratio of the reaction solution to dichloromethane being 1: 1.4; combining the organic phases obtained by extraction, and drying for 30min by using 2g of anhydrous sodium sulfate; after drying, filtering, carrying out column chromatography purification by using silica gel as a carrier, wherein the volume ratio of petroleum ether to ethyl acetate in the column chromatography is 1.5: 2.5, Compound A was obtained as a white solid, noted BocWG-OMe, in 94.3% yield.

Dissolving 1.5mmol of prepared BocWG-OMe in 9g of methanol aqueous solution, wherein the volume fraction of methanol in the methanol aqueous solution is 30%, adding 3mmol of hydrated lithium hydroxide after dissolving, and reacting at 20 ℃ for 3 h; and (3) completing the substitution reaction to obtain a mixed system, and performing TLC detection, wherein the volume ratio of dichloromethane to methanol is 35: 1; drying at 110 deg.C to remove methanol, adjusting pH of the dried mixed system to 4 with 10% potassium hydrogen sulfate solution, extracting with ethyl acetate for 4 times until the water phase has no ultraviolet absorption and no ninhydrin color reaction on GF254 thin layer plate, and stopping extraction. Collecting an organic phase obtained by extraction, and drying the organic phase by using anhydrous sodium sulfate, wherein the ratio of the organic phase to the anhydrous sodium sulfate is 5 mL: 2g, drying to constant weight; filtration and secondary drying after drying, followed by evaporation of the solvent to dryness at 120 ℃ gave compound B as a white solid, noted BocWG-OH, in 97.6% yield.

1.5mmol of prepared BocWG-OH and 1mmol of dendritic alkoxy ether G₁dissolving-OH in 18mL of dichloromethane, adding 0.675mmol of 4-dimethylaminopyridine after complete dissolution, and reacting at 0 ℃ for 25min under the conditions of nitrogen to complete a primary reaction; then adding 2.1mmol of 1-ethyl- (3-dimethylaminopropyl) carbodiimide hydrochloride, replacing nitrogen, and reacting at 0 ℃ for 25min to complete a secondary reaction; then carrying out esterification reaction for 14h at the temperature of 30 ℃ to finish the esterification reaction. After the reaction is finished, TLC detection is carried out, and the volume ratio of dichloromethane to methanol is 20: 1, extracting by using 10mL of saturated sodium chloride aqueous solution for 3 times, and collecting an organic phase; the dosage ratio of the organic phase to the anhydrous sodium sulfate is 10 mL: 1g, drying to constant weight; filtering after drying; carrying out column chromatography purification by using silica gel, wherein the volume ratio of dichloromethane to methanol in the column chromatography is 20: 1, evaporating the solvent to dryness at 80 ℃ to give Compound C as a pale yellow oily liquid, noted BocWG-G₁The yield was 64.13%.

1mmol of prepared BocWG-G was taken₁Dissolving in 10mL of dichloromethane, dropwise adding 22mmol of trifluoroacetic acid into a reaction system at the temperature of 0 ℃ at the speed of 1 drop/second, and reacting for 20min to complete the primary reaction after all the dropwise adding is finished; then the reaction is carried out for 3 hours at the temperature of 20 ℃ to complete the substitution reaction; after the reaction is finished, TLC detection is carried out, and the volume ratio of dichloromethane to methanol is 20: 1; then adding 30mL of methanol into the system to quench the reaction, and stirring for 40min at the rotating speed of 400 rpm; evaporating methanol and performing post-treatment; adding 15mL of dichloromethane into the system, and evaporating the dichloromethane to dryness to complete one post-treatment; after 4 post-treatments, compound D, recorded as TFA-WG-G, was obtained₁。

1mmol of the prepared TFA-WG-G was taken₁1mmol of 2- (2-nitroimidazol-1-yl) acetic acid and 1.2mmol of 1-hydroxybenzotriazole are dissolved in 50In mL of dichloromethane, using N, N-diisopropylethylamine to adjust the pH value to 10, replacing nitrogen, and reacting at the rotation speed of 400rpm at 0 ℃ for 30min to complete the primary reaction; then 1.5mmol of 1-ethyl- (3-dimethylaminopropyl) carbodiimide hydrochloride is added to react for 30min at the temperature of 0 ℃ and the rotating speed of 400rpm to complete the secondary reaction; after the secondary reaction is finished, reacting for 13 hours at 25 ℃ to carry out amidation reaction to obtain 30mL of a primary product; the crude product was washed with 30mL of 10% potassium hydrogensulfate solution and then extracted with 30mL of dichloromethane; the organic phase obtained by extraction was dried over 2g of anhydrous sodium sulfate; then, purification was performed by column chromatography with a volume ratio of dichloromethane to methanol of 20: 1, obtaining orange yellow oily matter which is double response dipeptide supramolecular monomer after purification and reduced pressure distillation, and marking as NI-WG-G₁Yield 21.6% of the total amount of NI-WG-G₁Dissolved in d₆in-DMSO, nmr detection was performed, as shown in fig. 12.

Taking NI-WG-G₁2mg, dissolving in 4mL deionized water, dissolving by using a vortex instrument, standing for 12 hours, and self-assembling to obtain the dual-response dipeptide supramolecular polymer for later use.

Preparing NI-WG-G of 2mg/mL₁Solution prepared by adopting variable-temperature ultraviolet-visible spectrum to NI-WG-G₁The solution was tested for its temperature sensitive behavior with a minimum critical phase transition temperature (LCST) of 41 ℃ and the results are shown in fig. 13.

To 3mLNI-WG-G₁100uL of reducing agent was added to the solution, the fluorescence intensity was measured once before the addition of the reducing agent, and then every 10min, and it was found that the fluorescence intensity increased with the increase in the reduction time during the reduction process, demonstrating that the product was gradually reduced. The change in fluorescence intensity was significant around 359.2nm, as shown in FIG. 14; according to the time and fluorescence change trend graph, the reduction time is obviously reduced in the change amplitude of the fluorescence intensity at 180min, as shown in FIG. 15, so that the reduction is completely finished at about 180 min.

Preparing NI-WG-G with different concentrations₁And adding naproxen into the solution, adding reducing agents with different concentrations, and observing the change of the fluorescence intensity of the solution. As shown in FIG. 16, naproxen at different concentrations showed strong fluorescence intensity, but different concentrationsNI-WG-G of concentration₁All have the condition of fluorescence quenching, the fluorescence intensity is lower, and after the medicine naproxen is added, the fluorescence intensity can be between the fluorescence intensity of naproxen and NI-WG-G₁In between, it can be shown that part of naproxen is coated, and after the reducing agent is added, the fluorescence intensity is raised, and it can be shown that the assembly body is decomposed and assembled, and part of naproxen is released.

The embodiments show that the invention provides a dual-response dipeptide supramolecular monomer, wherein tryptophan glycine dipeptide is taken as a self-assembly motif, a hydrophilic dendritic alkoxy ether chain and a hydrophobic structure are introduced, and the dipeptide molecule monomer NA-WG-G with dual responses of temperature and hypoxic environment is successfully prepared₁、NI-WG-G₁The monomer molecules are self-assembled in aqueous solution to form the dipeptide supramolecular polymer with dual response of temperature and hypoxic environment. The time dependence of the fluorescence intensity of the supramolecular polymer under the hypoxic condition is investigated through fluorescence spectroscopy, and the change of the fluorescence intensity by more than ten times before and after reduction is expected to be used as a fluorescence probe for medical image detection; meanwhile, the action of coating naproxen is researched, the release of the drug caused by polymer disassembly under the hypoxic condition is proved, and a research basis is provided for the research and development of a carrier of a novel nano-drug.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.