Synthesis method and application of benzothiazole type aggregation-induced emission enhanced fluorescent probe

Abstract

The invention discloses a synthesis method and application of a benzothiazole type aggregation-induced emission enhanced fluorescent probe, and the synthesis method of the benzothiazole type aggregation-induced emission enhanced fluorescent probe comprises the following steps: uniformly mixing an intermediate C, an intermediate A and a first organic solvent, adding a first alkali while stirring, refluxing for 24-28 hours while stirring, filtering, washing, and drying to obtain the benzothiazole type aggregation-induced emission enhanced fluorescent probe. The benzothiazole type aggregation-induced emission enhanced fluorescent probe is obtained by taking benzothiazole as a raw material, taking out the benzothiazole type aggregation-induced emission enhanced fluorescent probe, cooling the benzothiazole type aggregation-induced emission enhanced fluorescent probe to room temperature, performing rotary evaporation, performing column chromatography separation and performing rotary evaporation, and the benzothiazole type aggregation-induced emission enhanced fluorescent probe has excellent aggregation-induced emission enhancement performance and excellent solvent discoloration performance. The benzothiazole type aggregation-induced emission enhanced fluorescent probe has obvious fluorescence response to trace water in tetrahydrofuran, is high in response speed, can realize self-calibration detection, is low in detection limit, has a linear relationship between the fluorescence peak intensity and the trace water content, and can be used for trace water detection.

Description

Technical Field

[0001] The invention belongs to the field of fluorescent probes, and specifically relates to a synthesis method and application of a benzothiazole-type aggregation-induced luminescence enhanced fluorescent probe. Background Art

[0002] It is well known that the presence of trace water in chemical production may lead to problems such as reduced reaction yield and reaction quenching, and may even cause serious safety accidents. Therefore, efficient and convenient detection of trace water is undoubtedly of great practical significance. Traditional trace water detection methods often have disadvantages such as low sensitivity, slow response speed and poor convenience. Therefore, scientists have tried to apply organic fluorescent probes to the detection of trace water. However, most traditional organic fluorescent probes exhibit aggregation-induced quenching (ACQ) in trace water, that is, the organic fluorescent probes are quenched in an aggregated state, which seriously limits the application of fluorescent probes in trace water detection.

[0003] Completely opposite to the ACQ effect, aggregation-induced emission (AIE) molecules are a new type of fluorescent probe molecules developed in recent years. They can show fluorescence "on" performance in the aggregated state, and the fluorescence intensity is significantly reduced in dilute solutions, which greatly overcomes the shortcomings of traditional fluorescent molecules. With the deepening of research, scientists have successively developed aggregation-induced emission enhanced (AEE) fluorescent probes. AEE fluorescent probes can emit strong fluorescence in dilute solutions or aggregated states, which lays the foundation for the application of fluorescent probes in liquid systems. Although AEE probes have many advantages, their molecular templates are single and they can often only respond to a single external stimulus. Therefore, it is urgent to develop an AEE fluorescent probe that can respond to multiple stimuli. Summary of the invention

[0004] In view of the deficiencies of the prior art, the object of the present invention is to provide a benzothiazole-type aggregation-induced emission enhanced fluorescent probe.

[0005] Another object of the present invention is to provide a method for synthesizing a benzothiazole-type aggregation-induced emission-enhanced fluorescent probe. The method designs and synthesizes a benzothiazole-type aggregation-induced emission-enhanced fluorescent probe by constructing an A'-D-π-A type molecular skeleton.

[0006] Another object of the present invention is to provide a benzothiazole-type aggregation-induced emission enhanced fluorescent probe for use in distinguishing different organic solvents based on polarity.

[0007] Another object of the present invention is to provide a benzothiazole-type aggregation-induced emission enhanced fluorescent probe for use in detecting trace water content in a water-soluble organic solvent.

[0008] Another object of the present invention is to provide a benzothiazole-type aggregation-induced emission enhanced fluorescent probe for use in comparing the length of time that edible oil is used for frying.

[0009] The purpose of the present invention is achieved through the following technical solutions.

[0010] A benzothiazole-type aggregation-induced emission enhanced fluorescent probe, the structural formula of which is as follows: .

[0011] A method for synthesizing a benzothiazole-type aggregation-induced emission enhanced fluorescent probe comprises the following steps: The intermediate C, the intermediate A and the first organic solvent are mixed uniformly, the first base is added under stirring, the mixture is refluxed for 24 to 28 hours under stirring, cooled to room temperature of 20 to 25°C, and rotary evaporation, column chromatography separation and rotary evaporation are performed in sequence to obtain a benzothiazole-type aggregation-induced emission enhanced fluorescent probe, wherein the structural formula of the intermediate C is ; The structural formula of intermediate A is ; Calculated by amount of substance, the ratio of intermediate C to intermediate A is (1~10):(1~5).

[0012] In the above technical scheme, the first base is one or more of sodium ethoxide and piperidine. When the first base is sodium ethoxide, the ratio of the amount of intermediate A, the volume of the first organic solvent and the mass of the first base is (1-5):50:(0.5-2); when the first base is piperidine, the ratio of the amount of intermediate A, the volume of the first organic solvent and the volume of the first base is (1-5):50:(2-10), the unit of the amount of the substance is mmol, the unit of the volume is mL, and the unit of the mass is g.

[0013] In the above technical solution, the first organic solvent is one or more of DMSO, DMF, anhydrous ethanol, THF, toluene and acetonitrile.

[0014] In the above technical scheme, the method for synthesizing intermediate A comprises: uniformly mixing 2,6-dimethyl-4-pyrone, 1,3-indanedione and acetic anhydride to obtain a reaction solution, refluxing the reaction solution under stirring conditions for 6 to 9 hours, terminating the reaction, adjusting the pH to neutral with an aqueous sodium hydroxide solution, sequentially performing extraction, washing, rotary evaporation, drying, and column chromatography separation to obtain intermediate A, wherein the ratio of the amount of 2,6-dimethyl-4-pyrone, the amount of 1,3-indanedione and the volume of acetic anhydride is (1 to 5): (1 to 5): 10, the unit of the amount of the substance is mmol, and the unit of the volume is mL.

[0015] In the above technical solution, the drying temperature is 60-90° C., and the drying time is 4-6 hours.

[0016] In the above technical scheme, the method for synthesizing intermediate C includes: uniformly mixing 4-diphenylaminobenzaldehyde, 2-methylbenzothiazole, an alcohol solution and a second base to obtain a mixed solution, refluxing the mixed solution under stirring conditions for 12 to 15 hours, terminating the reaction, and sequentially performing extraction, washing, rotary evaporation, drying, and column chromatography separation to obtain intermediate B; uniformly dispersing intermediate B in a second organic solvent, adding phosphorus oxychloride, and stirring at 80 to 100° C. for 12 to 15 hours to obtain intermediate C.

[0017] In the above technical solution, the structural formula of the intermediate B is .

[0018] In the above technical solution, the second organic solvent is one or more of DMSO, DMF, anhydrous ethanol, toluene and acetonitrile, and the second base is one or more of sodium hydroxide, potassium hydroxide, sodium ethoxide and piperidine.

[0019] In the above technical solution, the alcohol solution is one or more of anhydrous ethanol, methanol and butanol.

[0020] In the above technical solution, the ratio of 4-diphenylaminobenzaldehyde, 2-methylbenzothiazole and the second base is (1-5): (1-5): (2-3) in terms of the amount of the substances.

[0021] In the above technical solution, the ratio of intermediate B to phosphorus oxychloride is 1:(6-8) in terms of molar fractions.

[0022] In the above technical solution, the ratio of the amount of 4-diphenylaminobenzaldehyde to the volume of the alcohol solution is (1-5):10, the unit of the amount of the substance is mmol, and the unit of the volume is mL.

[0023] In the above technical solution, the ratio of the amount of the intermediate B to the volume of the second organic solvent is 1: (40-60), the unit of the amount of the substance is mmol, and the unit of the volume is mL.

[0024] The above-mentioned benzothiazole-type aggregation-induced emission enhanced fluorescent probe is used to distinguish different organic solvents based on the strength of polarity.

[0025] The above-mentioned benzothiazole-type aggregation-induced emission enhanced fluorescent probe is used to compare the length of time that edible oil is used for frying.

[0026] In the above technical solution, the edible oil includes: one or more of peanut oil, soybean oil and corn oil.

[0027] The above-mentioned benzothiazole-type aggregation-induced emission enhanced fluorescent probe is used to detect trace water content in water-soluble organic solvents.

[0028] In the above technical solution, the water-soluble organic solvent includes: one or more of tetrahydrofuran, 1,4-dioxane and acetone.

[0029] Compared with the prior art, the present invention has the following beneficial effects: (1) The benzothiazole-based aggregation-induced emission-enhanced fluorescent probe of the present invention has excellent aggregation-induced emission-enhanced performance and excellent solvent color change performance.

[0030] (2) The benzothiazole-type aggregation-induced emission enhanced fluorescence probe of the present invention can be used to detect the quality of edible oil. As the frying time increases, the viscosity of the edible oil gradually increases, and the corresponding fluorescence intensity gradually increases, so a preliminary inspection of the quality of the edible oil can be achieved.

[0031] (3) The benzothiazole-type aggregation-induced emission enhanced fluorescent probe of the present invention has an obvious fluorescent response to trace water in the water-soluble organic solvent tetrahydrofuran, has a fast response speed, can achieve self-calibration detection, and has a low detection limit of 0.021%. When the trace water content is between 0% and 1.20% (v / v), the fluorescence peak intensity of the benzothiazole-type aggregation-induced emission enhanced fluorescent probe shows a linear decrease with the increase of the trace water content, and the linear relationship is y=-2258.53994x+5455.6281. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 The hydrogen spectrum of the benzothiazole-type aggregation-induced emission enhanced fluorescent probe synthesized in Example 1; Figure 2 The carbon spectrum of the benzothiazole-type aggregation-induced emission enhanced fluorescent probe synthesized in Example 1; Figure 3 The fluorescence emission spectra of the benzothiazole-type aggregation-induced emission enhanced fluorescent probe synthesized in Example 1 in dichloromethane with different volume percentages of n-hexane; Figure 4 The fluorescence emission spectra of the benzothiazole-type aggregation-induced emission enhanced fluorescent probe synthesized in Example 1 in different organic solvents; Figure 5 The fluorescence emission spectra of the benzothiazole-type aggregation-induced emission enhanced fluorescent probe synthesized in Example 1 in peanut oil after being fried for different times; Figure 6The fluorescence emission spectra of the benzothiazole-type aggregation-induced emission enhanced fluorescent probe synthesized in Example 1 in tetrahydrofuran with different water contents; Figure 7 This is the linear relationship between the fluorescence peak intensity of the benzothiazole-type aggregation-induced emission enhanced fluorescent probe in tetrahydrofuran with different water contents and the trace water content. DETAILED DESCRIPTION

[0033] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0034] Embodiment 1~5 A method for synthesizing a benzothiazole-type aggregation-induced emission enhanced fluorescent probe comprises the following steps: Synthesis of intermediate A:

[0035] 2,6-dimethyl-4-pyrone and 1,3-indanedione were placed in a three-necked flask, acetic anhydride was added and mixed evenly to obtain a reaction solution. The reaction solution was refluxed at the reflux temperature of acetic anhydride for 1 hour under stirring conditions to terminate the reaction, and the pH was adjusted to neutral with a sodium hydroxide aqueous solution (the content of sodium hydroxide in the sodium hydroxide aqueous solution was 30wt%), and extracted with dichloromethane to obtain an organic phase, which was washed with a saturated NaCl aqueous solution for 3 times, and then rotary evaporated in sequence, placed in an oven at 60°C for 4 hours, and separated by column chromatography (the eluent of the column chromatography was a mixture of petroleum ether and ethyl acetate, and the ratio of petroleum ether to ethyl acetate was 10:1 by volume), to obtain a yellow solid as intermediate A, wherein the ratio of the amount of substance of 2,6-dimethyl-4-pyrone, the amount of substance of 1,3-indanedione and the volume of acetic anhydride was G, the unit of the amount of substance was mmol, and the unit of the volume was mL.

[0036] G and H1 of the intermediate A synthesized in Examples 1 to 5 are shown in Table 1.

[0037] Table 1

[0038] Synthesis of intermediate C:

[0039] 4-Diphenylaminobenzaldehyde and 2-methylbenzothiazole were placed in a three-necked flask, and the alcohol solution and the second base were added and mixed evenly to obtain a mixed solution. The mixed solution was refluxed at the reflux temperature of the alcohol solution under stirring conditions for 2 hours to terminate the reaction, and extracted with dichloromethane to obtain an organic phase, which was washed with a saturated NaCl aqueous solution for 3 times, rotary evaporated, placed in an oven at 60°C to dry for 4 hours, and separated by column chromatography (the eluent of the column chromatography was a mixture of petroleum ether and ethyl acetate, and the ratio of petroleum ether to ethyl acetate was 8:1 by volume) to obtain intermediate B. The intermediate B is uniformly dispersed in the second organic solvent, phosphorus oxychloride is added, and the mixture is stirred at T°C for 3 hours to obtain an intermediate C, wherein, by molar fraction, the ratio of 4-diphenylaminobenzaldehyde, 2-methylbenzothiazole and the second base is W, and the ratio of the intermediate B to phosphorus oxychloride is N; the ratio of the molar fraction of 4-diphenylaminobenzaldehyde to the volume fraction of the alcohol solution is M; the ratio of the molar fraction of the intermediate B to the volume fraction of the second organic solvent is 1:50, the unit of the molar fraction is mmol, and the unit of the volume fraction is mL.

[0040] The W, N, M, H2, H3, T, alcohol solution, second base and second organic solvent of the intermediate C synthesized in Examples 1 to 5 are shown in Table 2.

[0041] Table 2

[0042] Synthesis of benzothiazole-based aggregation-induced emission enhanced fluorescence probe:

[0043] The intermediate C and the intermediate A are placed in a three-necked flask, and the first organic solvent is added and mixed evenly. The first base is quickly added under stirring, and refluxed at the reflux temperature of the first organic solvent for 4 hours under stirring. After the reaction is completed, the mixture is cooled to a room temperature of 20-25° C., and rotary evaporation and column chromatography separation are performed in sequence (the eluent of the column chromatography is a mixture of petroleum ether and ethyl acetate, and the ratio of petroleum ether to ethyl acetate is 8:1 by volume), and rotary evaporation is performed to obtain a benzothiazole-type aggregation-induced emission enhanced fluorescent probe, wherein the ratio of intermediate C to intermediate A by amount of substance is X; the first base is sodium ethoxide or piperidine, and when the first base is sodium ethoxide, the ratio of the amount of intermediate A, the volume of the first organic solvent, and the mass of the first base (sodium ethoxide) is V; when the first base is piperidine, the ratio of the amount of intermediate A, the volume of the first organic solvent, and the volume of the first base (piperidine) is V, and the unit of the amount of substance is mmol, the unit of the volume is mL, and the unit of the mass is g.

[0044] X, V, H4, the first organic solvent and the first base of the benzothiazole-type aggregation-induced emission enhanced fluorescent probes synthesized in Examples 1 to 5 are shown in Table 3; the hydrogen spectrum of the benzothiazole-type aggregation-induced emission enhanced fluorescent probe synthesized in Example 1 is shown in Figure 1 As shown, the carbon spectrum is Figure 2 shown.

[0045] Table 3

[0046] Example 6 A certain amount of the benzothiazole-type aggregation-induced emission enhanced fluorescent probe synthesized in Example 1 was weighed and mixed with dichloromethane to prepare a benzothiazole-type aggregation-induced emission enhanced fluorescent probe with a concentration of 1.0×10 -4 mol / L dichloromethane mother liquor. The dichloromethane mother liquor was placed in an ultrasonic cleaning instrument, and n-hexane (as a poor solvent) was slowly added under ultrasound, or no n-hexane was added, to obtain a test solution, in which the volume percentage of n-hexane in the test solution was 0%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80% and 90%, respectively.

[0047] The mixed solution was immediately tested for fluorescence emission at an excitation wavelength of 525 nm using a fluorescence spectrophotometer. Figure 3 As shown. Figure 3 It can be seen that with the increase of the poor solvent content (in the range of 0-50%), the single bond rotation in the benzothiazole-type aggregation-induced emission enhanced fluorescent probe is hindered, and the fluorescence intensity gradually increases; when the volume percentage of the poor solvent exceeds 50%, with the further increase of the poor solvent content, amorphous nanoparticles appear in the test liquid, and the fluorescence intensity decreases, but still shows fluorescence emission. In summary, the benzothiazole-type aggregation-induced emission enhanced fluorescent probe can show fluorescence emission in both liquid and aggregated states. When the volume percentage of n-hexane is 50%, the fluorescence peak intensity is the strongest, indicating that the benzothiazole-type aggregation-induced emission enhanced fluorescent probe has aggregation-induced emission enhancement performance.

[0048] Example 7

[0049] A certain amount of the benzothiazole-type aggregation-induced emission enhanced fluorescent probe synthesized in Example 1 was weighed and mixed with an organic solvent to prepare a benzothiazole-type aggregation-induced emission enhanced fluorescent probe with a concentration of 1.0×10 -4 mol / L detection solution, and the organic solvent is one of toluene, THF, dichloromethane and N,N-dimethylformamide.

[0050] The mixed test solution was immediately tested for fluorescence emission at an excitation wavelength of 525 nm using a fluorescence spectrophotometer and normalized. Figure 4As shown. Figure 4 It can be seen that the benzothiazole-type aggregation-induced emission enhanced fluorescent probe exhibits excellent solvent color change performance. This is because the benzothiazole-type aggregation-induced emission enhanced fluorescent probe has a good electron donor (triphenylamine structure) and electron acceptor (indanone, γ-pyrone and benzothiazole structure), the charge separation degree of the molecule is increased, and it can be better stabilized by solvation. Different solvent polarities have different stabilizing effects on the excited state and ground state of the molecule, which changes the fluorescence emission position of the benzothiazole-type aggregation-induced emission enhanced fluorescent probe, and can then perform qualitative detection of organic solvents of different polarities.

[0051] Example 8

[0052] Pour 2L of fresh peanut oil into a pot, add fresh French fries in batches for frying, add 30g of fresh French fries to each batch, and fry each batch of fresh French fries for 20 min before taking them out. The total cumulative frying time is 20h. At the Yth h of frying, take 4mL of peanut oil in the pot as the oil product and mix it with the dichloromethane mother liquor (1mL) in Example 6 to obtain oil sample liquid, Yh =4h, 8h, 12h, 16h and 20h.

[0053] The mixed oil sample liquid was immediately tested for its fluorescence emission at an excitation wavelength of 525 nm using a fluorescence spectrophotometer. Figure 5 As shown. Figure 5 It can be seen that with the increase of frying time, the fluorescence intensity of the benzothiazole-type aggregation-induced emission enhanced fluorescence probe in the oil sample liquid shows a significant increase. This is because with the extension of frying time, the viscosity of the oil gradually increases, which hinders the single bond rotation in the benzothiazole-type aggregation-induced emission enhanced fluorescence probe, thereby leading to an increase in fluorescence intensity. This is consistent with the result of the mechanism of hindered intramolecular rotation of the AEE probe.

[0054] Example 9

[0055] A certain amount of the benzothiazole-type aggregation-induced emission enhanced fluorescent probe synthesized in Example 1 was weighed and dissolved in tetrahydrofuran to prepare a benzothiazole-type aggregation-induced emission enhanced fluorescent probe with a concentration of 1.0×10 -4 mol / L tetrahydrofuran mother solution. The tetrahydrofuran mother solution was placed in an ultrasonic cleaning apparatus, and distilled water was slowly added or not added (as trace water) under ultrasound to prepare test solutions with different trace water contents, and the trace water contents of the test solutions (unit: % (v / v)) were 0, 0.3, 0.6, 1, 1.2, 1.5, 1.8, 2, 3, 4, 5, 6, 7, 8, 9 and 10, respectively.

[0056] The mixed test solution was immediately tested for fluorescence emission at an excitation wavelength of 525 nm using a fluorescence spectrophotometer. Figure 6 As shown by Figure 6 It can be seen that when the test liquid does not contain water, the fluorescence intensity of the test liquid is the highest; as the trace water content gradually increases, the fluorescence intensity of the test liquid decreases rapidly due to the influence of the intramolecular charge transfer phenomenon. When the trace water content is 1.5% (v / v), the fluorescence intensity of the test liquid has dropped to 47% of that when it does not contain water. Among them, when the trace water content is between 0 and 1.2% (v / v), the fluorescence peak intensity of the benzothiazole-type aggregation-induced emission enhanced fluorescent probe in the test liquid shows a good linear relationship with the trace water content, such as Figure 7 As shown, the linear relationship formula is y=-2258.53994x+5455.6281, y represents the fluorescence peak intensity, and x represents the trace water content (unit: % (v / v)). According to the detection limit (LOD) formula in the literature (Highly sensitive sensing of polarity, temperature, and acid gases by a smartfluorescent molecule, Sensors&Actuators: B. Chemical 344 (2021) 130120), the extremely low detection limit of trace water content is 0.021%.

[0057] The test liquid with a trace water content of 0.8% (v / v) was used as an unknown sample. Its fluorescence emission at an excitation wavelength of 525nm was tested using a fluorescence spectrophotometer, and the fluorescence peak intensity was 3632.5. According to the above linear relationship formula, the theoretical value of the trace water content of the unknown sample was calculated to be 0.8072% (v / v), with an error of 0.9%. Therefore, this linear formula can be used to detect trace water in the water-soluble organic solvent tetrahydrofuran.

[0058] The benzothiazole-type aggregation-induced emission-enhanced fluorescent probes synthesized in the above Examples 2 to 5 have the same technical effects as the benzothiazole-type aggregation-induced emission-enhanced fluorescent probe synthesized in Example 1.

[0059] The present invention is described above by way of example. It should be noted that, without departing from the core of the present invention, any simple deformation, modification or other equivalent replacement that can be made by those skilled in the art without inventive effort falls within the protection scope of the present invention.

Claims

1. A benzothiazole-type aggregation-induced emission enhanced fluorescent probe, characterized in that: Its structural formula is as follows: 。 2. The method for synthesizing the benzothiazole-type aggregation-induced emission enhanced fluorescent probe according to claim 1, characterized in that: The following steps are involved: The intermediate C, the intermediate A and the first organic solvent are mixed uniformly, the first base is added under stirring, the mixture is refluxed for 24 to 28 hours under stirring, cooled to room temperature of 20 to 25°C, and rotary evaporation, column chromatography separation and rotary evaporation are performed in sequence to obtain a benzothiazole-type aggregation-induced emission enhanced fluorescent probe, wherein the structural formula of the intermediate C is ; The structural formula of intermediate A is ; Calculated by amount of substance, the ratio of intermediate C to intermediate A is (1~10):(1~5).

3. The synthesis method according to claim 2, characterized in that The first base is one or more of sodium ethoxide and piperidine. When the first base is sodium ethoxide, the ratio of the amount of intermediate A, the volume of the first organic solvent and the mass of the first base is (1-5):50:(0.5-2). When the first base is piperidine, the ratio of the amount of intermediate A, the volume of the first organic solvent and the volume of the first base is (1-5):50:(2-10). The unit of the amount of substance is mmol, the unit of the volume is mL, and the unit of the mass is g.

4. The synthesis method according to claim 2, characterized in that The first organic solvent is one or more of DMSO, DMF, anhydrous ethanol, THF, toluene and acetonitrile.

5. The synthesis method according to claim 2, characterized in that The method for synthesizing intermediate A comprises: uniformly mixing 2,6-dimethyl-4-pyrone, 1,3-indanedione and acetic anhydride to obtain a reaction solution, refluxing the reaction solution under stirring conditions for 6 to 9 hours, terminating the reaction, adjusting the pH to neutral with a sodium hydroxide aqueous solution, sequentially performing extraction, washing, rotary evaporation, drying and column chromatography separation to obtain intermediate A, wherein the ratio of the amount of 2,6-dimethyl-4-pyrone, the amount of 1,3-indanedione and the volume of acetic anhydride is (1 to 5): (1 to 5): 10, the unit of the amount of the substance is mmol, and the unit of the volume is mL.

6. The synthesis method according to claim 2, characterized in that The method for synthesizing intermediate C comprises: uniformly mixing 4-diphenylaminobenzaldehyde, 2-methylbenzothiazole, an alcohol solution and a second base to obtain a mixed solution, refluxing the mixed solution under stirring conditions for 12 to 15 hours, terminating the reaction, sequentially performing extraction, washing, rotary evaporation, drying, and column chromatography separation to obtain intermediate B; uniformly dispersing intermediate B in a second organic solvent, adding phosphorus oxychloride, and stirring at 80 to 100° C. for 12 to 15 hours to obtain intermediate C; The structural formula of the intermediate B is ; The second organic solvent is one or more of DMSO, DMF, anhydrous ethanol, toluene and acetonitrile; the second base is one or more of sodium hydroxide, potassium hydroxide, sodium ethoxide and piperidine; the alcohol solution is one or more of anhydrous ethanol, methanol and butanol; Calculated by molar mass, the ratio of 4-diphenylaminobenzaldehyde, 2-methylbenzothiazole and the second base is (1-5): (1-5): (2-3); calculated by molar mass, the ratio of intermediate B and phosphorus oxychloride is 1: (6-8).

7. Use of the benzothiazole-type aggregation-induced emission enhanced fluorescent probe as claimed in claim 1 in distinguishing different organic solvents based on the strength of their polarity.

8. Use of the benzothiazole-type aggregation-induced emission enhanced fluorescent probe as claimed in claim 1 in comparing the length of time that edible oil is used for frying.

9. Use of the benzothiazole-based aggregation-induced emission enhanced fluorescent probe as claimed in claim 1 in detecting trace water content in a water-soluble organic solvent.

10. The use according to claim 9, characterized in that: The water-soluble organic solvent includes one or more of tetrahydrofuran, 1,4-dioxane and acetone.

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