A benzothiazole derivative for detecting hydrazine, a preparation method and application thereof, and a kit for detecting hydrazine

Abstract

The invention provides a benzothiazole derivative for detecting hydrazine, a preparation method and application thereof, and a kit for detecting hydrazine, wherein the benzothiazole derivative has a structural formula shown in Formula I: the derivative is synthesized from 2-(2-aminophenyl)benzothiazole through a series of reactions, has a maximum fluorescence emission wavelength of 640nm, has strong anti-interference ability, and has a short response time to hydrazine hydrate.

Description

Technical Field

[0001] The invention relates to a benzothiazole derivative for detecting hydrazine, a preparation method and application thereof, and a kit for detecting hydrazine, belonging to the technical field of detection. Background Art

[0002] Hydrazine (N2H4) is a colorless liquid inorganic compound with strong alkalinity and reducing properties. It can be used as a corrosion inhibitor in heating systems. At the same time, it can also be used as an important industrial raw material in the manufacture of medicines, pesticides, chemical dyes, etc., and as a high-energy fuel in rocket propulsion and missile systems. However, hydrazine is highly toxic and can enter the human body through breathing, penetration, etc., further damaging the lungs, liver, kidneys and nervous system. IARC's comment on the carcinogenicity of hydrazine is: G2B, a suspected human carcinogen. Therefore, the selective identification and sensitive detection of hydrazine in the environment and biological systems are increasingly valued.

[0003] Conventional detection techniques for hydrazine mainly include titration, electrochemical method, chromatography and chemiluminescence. Compared with traditional methods, fluorescence analysis is widely used for the detection of metal ions, anions, biological small molecules, macromolecules and other substances due to its excellent selectivity and sensitivity, especially non-invasive damage to biological samples. For example, the invention patent application with application number CN201710891874.4, entitled "A fluorescent probe for visual detection of hydrazine based on benzothiazole, its preparation method and use", discloses a benzothiazole fluorescent probe molecule for detecting hydrazine, which has simple synthesis steps and is easy to use. However, its maximum emission wavelength is only 406nm, and the wavelength of this light is very short, so some problems may arise during the application process:

[0004] 1. The background fluorescence is too strong, causing background interference;

[0005] 2. Greater light damage to cells and tissues;

[0006] 3. Weaker penetration into tissues.

[0007] One of the important directions and trends in current research on fluorescent probe molecules is to develop light with longer wavelengths to overcome the above-mentioned shortcomings. Summary of the invention

[0008] Aiming at the problem that the wavelength is too short in the current fluorescence detection of hydrazine, the present invention proposes a benzothiazole derivative for detecting hydrazine, a preparation method and application thereof, and a kit for detecting hydrazine, which greatly prolongs the wavelength of the maximum emission light and shortens the response time with hydrazine hydrate.

[0009] The technical means adopted by the present invention to solve the above problems are: a benzothiazole derivative for detecting hydrazine, having the structural formula shown in Formula I:

[0010]

[0011] A method for preparing a benzothiazole derivative for detecting hydrazine comprises the following steps:

[0012] (1) 2-(2-aminophenyl)benzothiazole and trifluoroacetyl chloride were stirred in pyridine solvent at room temperature until the reaction was completed, poured into pure water, the pH was adjusted to near neutral, filtered, washed and dried the filter cake, and purified by column chromatography to obtain a white product ABTA:

[0013]

[0014] The molar ratio of ABT to trifluoroacetyl chloride is 1:1.5-4, and the dosage ratio of ABT to solvent is 1mmol:5-40mL; and an acidic solution such as 2%-8% dilute hydrochloric acid or dilute acetic acid is used to adjust the pH.

[0015] (2) ABTA and solvent acetic anhydride are stirred in a water bath at 40-60° C., and a glacial acetic acid solution containing nitric acid is slowly added to the reaction system using a microinjection pump (the addition rate is 0.08-0.12 mL / min). The mixture is stirred in a water bath at 40-60° C. until completion, poured into pure water, the pH is adjusted to near neutral, filtered, washed, and dried, and the filter cake is purified by column chromatography to obtain a light yellow product ABTA-NO2:

[0016]

[0017] The dosage ratio of ABTA to nitric acid is 1mmol:0.08-0.15mL, and the dosage ratio of ABTA to solvent is 1mmol:7-40mL; an alkaline solution such as sodium hydroxide or potassium hydroxide is used to adjust the pH;

[0018] (3) ABTA-NO2 was dissolved in tetrahydrofuran solvent, and 10% Pd / C was added as a catalyst. The mixture was stirred at room temperature under hydrogen until the reaction was completed. The filtrate was filtered and collected, and concentrated under reduced pressure and purified by column chromatography to obtain the product ABTA-NH2:

[0019]

[0020] The ratio of ABTA-NO2 to solvent is 1mmol:15-50mL;

[0021] (4) ABTT-NH2, acetic acid, and phthalic anhydride were heated to reflux until the reaction was complete, and the acetic acid was removed by distillation under reduced pressure. The target molecular probe ABTAP was obtained by column chromatography separation and purification:

[0022]

[0023] The molar ratio of ABTT-NH2 to phthalic anhydride is 1:2-3, and the dosage ratio of ABTT-NH2 to acetic acid is 1mmol:15-40mL.

[0024] The detection principle of the ABTAP probe of the present invention is that due to the photoinduced electron transfer (PET) effect of maleimide on the probe, the probe itself has no fluorescence. When the probe responds to hydrazine, the maleimide reacts to become an amino group, so that the PET effect is inhibited, and the fluorescence of the probe at 640nm is restored, thereby realizing the detection of hydrazine. The detection principle is shown in the following figure:

[0025]

[0026] The beneficial effects of the present invention are:

[0027] 1. The maximum fluorescence emission wavelength of the compound of the present invention is 640 nm when detected, and the anti-interference ability is strong; and the response time to hydrazine hydrate is short.

[0028] 2. When the compound of the present invention is used as a fluorescent probe for hydrazine in an aqueous phase, it can be detected in a neutral environment, and the detection conditions are mild.

[0029] 3. The compounds of the present invention have excellent specificity for the detection of hydrazine, and other anions and cations will not cause interference.

[0030] 4. The compounds of the present invention have good sensitivity to hydrazine, with a detection limit of 0.718 μM, which is lower than the 10 ppm specified by EPA. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1A This is an emission spectrum diagram of the fluorescence intensity of the fluorescent probe of Example 2 as it changes with the hydrazine concentration;

[0032] Figure 1B is a linear relationship diagram between the fluorescence intensity and hydrazine concentration of the fluorescent probe of Example 2;

[0033] Figure 2 is a graph showing the selectivity of the fluorescent probe for hydrazine in Example 3;

[0034] Figure 3 This is the time response diagram of the fluorescent probe of Example 4 to hydrazine. DETAILED DESCRIPTION

[0035] The present invention is further described below in conjunction with the accompanying drawings.

[0036] Embodiment 1

[0037] This example is the synthesis of benzothiazole derivatives for detecting hydrazine, and the route is as follows:

[0038]

[0039] Synthesis of Compound ABTA

[0040] Weigh compound ABT (960.0 mg, 4.0 mmol) and place it in a 100 mL round-bottom flask, add 30 mL of pyridine, stir at room temperature, add trifluoroacetyl chloride (1.06 g, 8.0 mmol) to the round-bottom flask, and continue to stir at room temperature. Monitor the reaction progress by TLC. After the reaction is completed, pour the reaction system into pure water, adjust the pH to near neutral with 5% dilute hydrochloric acid solution, and a large amount of white precipitate will precipitate. Filter under reduced pressure to obtain a solid precipitate, wash it with a saturated sodium chloride solution, and place the collected filter cake in an oven and dry it at 50 ° C. Finally, separate and purify it by column chromatography to obtain 1.25 g of a white product with a yield of 97.2%. 1 H NMR (500MHz, CDCl3) δ12.27(s,1H),8.10(d,J=8.1Hz,1H),7.85(d,J=8.0Hz,1H),7.73(d,J=8.3Hz,1H),7.68 (d, J=7.8Hz, 1H), 7.47 (t, J=7.6Hz, 1H), 7.34 (t, J=7.5Hz, 1H), 7.36 (t, J=7.8Hz, 1H), 7.08 (t, J=7.5Hz, 1H).

[0041] Synthesis of Compound ABTA-NH2

[0042] Weigh the compound ABTA (966.93 mg, 3.0 mmol) and place it in a 50 mL round-bottom flask, add 25 mL acetic anhydride as the reaction solvent, and stir in a water bath at 50 ° C. Take 0.3 mL nitric acid and dissolve it in 3 mL glacial acetic acid. Use a micro-injection pump to slowly add the glacial acetic acid solution of nitric acid to the reaction system at a rate of 0.1 mL / min. After the addition is complete, continue to stir in a water bath at 50 ° C. Monitor the reaction progress by TLC. After the reaction is completed and the reaction system is cooled to room temperature, pour it into pure water. Use 1 M NaOH solution to adjust the pH of the system to near neutrality, and a large amount of yellow-brown viscous solid precipitates. Collect the filter cake after filtration and place it in an oven for drying. Finally, separate and purify it by column chromatography to obtain a light yellow product ABTA-NO2.

[0043] Weigh the compound ABTT-NO2 (734.60 mg, 2.0 mmol) into a 100 mL round-bottom flask, add 50 mL of tetrahydrofuran to dissolve, weigh 2 mg of 10% Pd / C as a catalyst and add it to the reaction system, evacuate the reaction system and introduce hydrogen, react under stirring at room temperature, monitor the reaction progress by TLC, after the reaction is completed, remove the reaction system, filter, and obtain a yellow-brown filtrate. Remove tetrahydrofuran by vacuum distillation, purify by column chromatography, and obtain 213.86 mg of the product with a yield of 31.7%. 1 H NMR (500MHz, CDCl3) δ11.11(s,1H),8.11(d,J=8.3Hz,1H),7.88(d,J=8.1Hz,1H),7.69(d,J=8.8Hz, 1H), 7.66 (t, J = 7.7Hz, 1H), 7.54 (t, J = 7.6Hz, 1H), 6.92 (s, 1H), 6.82 (d, J = 8.7Hz, 1H), 3.68 (s, 2H).

[0044] Synthesis of Compound ABTAP

[0045] The compound ABTT-NH2 (168.66 mg, 0.5 mmol) was weighed and placed in a 25 mL round-bottom flask. 10 mL of acetic acid was added as a solvent. After sufficient dissolution, phthalic anhydride (177.73 mg, 1.2 mmol) was added to the reaction system. The mixture was heated to reflux for reaction. The reaction progress was monitored by TLC. After the reaction was completed, the acetic acid was removed by vacuum distillation. The target molecular probe ABTAP was separated and purified by column chromatography to obtain 197.72 mg with a yield of 84.6%. 1 H NMR (500MHz, CDCl3) δ11.58(s,1H),8.11(d,J=8.2Hz,1H),8.05(d,J=7.8Hz,2H),7.92(t,J=8.0Hz,2H),7.86(d,J=8.1Hz,1H ),7.63(d,J=8.6Hz,1H),7.64(t,J=7.7Hz,1H),7.52(t,J=7.6Hz,1H),6.81(s,1H),6.65(d,J=8.6Hz,1H).HRMS(m / z):calcd for C 23 H 12 F3N3O3S,467.0551; found [M+H] + ,468.0713.

[0046] Embodiment 2

[0047] This example is an experiment on the fluorescence response of a fluorescent molecular probe to hydrazine, and tests the effect of different concentrations of hydrazine (0-100 μM) on the fluorescence spectrum of the probe (10 μM). Figure 1B The linear relationship between the fluorescence intensity at 640 nm and the concentration of hydrazine added was obtained in a system of PBS buffer solution (0.01 M, pH = 7.4) and acetonitrile (5:5, V / V), and all spectral measurements were taken at 25°C after hydrazine was fully added for 20 minutes.

[0048] from Figure 1A It can be seen that with the increase of hydrazine concentration in the probe solution, the fluorescence emission peak at 640 nm gradually increases, and in the range of 0-10 μM hydrazine concentration, it has a good linear relationship with the fluorescence intensity at 640 nm (R 2 =99408). Therefore, the probe of the present invention can achieve quantitative detection of hydrazine with a detection limit as low as 0.718 μM.

[0049] Embodiment 3

[0050] This example shows the effect of different analytes on the fluorescence spectrum of fluorescent molecular probes.

[0051] Analytes include: ethylenediamine (EDA), diethylamine (DEA), triethylamine (TEA), aniline, chloride ion (Cl - ), sulfate ion (SO4 2- ), nitrate ion (NO3 - ), hydrazine, wherein the concentration of hydrazine is 10 μM, the concentration of other analytes is 100 μM, and the concentration of the probe is 10 μM. The above determination is carried out in a system of PBS buffer solution (0.01 M, pH = 7.4) and acetonitrile (5:5, V / V), and all spectral tests are measured at 25°C after hydrazine is added for full response for 20 minutes.

[0052] The results are as follows Figure 2 As shown in the bar graph, Figure 2 It can be seen that the probe has a high selectivity for hydrazine and can specifically respond to hydrazine without being affected.

[0053] Embodiment 4

[0054] This example is a determination of the time response of the fluorescent molecular probe to hydrazine.

[0055] A response system with a probe concentration of 10 μM and a hydrazine concentration of 10 μM (PBS:acetonitrile=5:5, v / v) was prepared, and the change in fluorescence intensity at 640 nm was scanned using the "time-scan" mode to obtain the time response curve of the probe to hydrazine. The results are as follows: Figure 3 As shown. Figure 3It can be seen that the fluorescence intensity of the system at 640nm gradually increases and reaches the maximum value at about 90s. Compared with the response speed of the reported hydrazine probe (usually 30-60min), the probe ABTAP responds to hydrazine very quickly, so it has higher application value in the rapid detection of hydrazine.

[0056] The above embodiments are only used to illustrate the present invention, rather than to limit the present invention. Technicians in the relevant technical field may make various changes or modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions should also fall within the protection scope of the present invention, and the protection scope of the present invention should be defined by the claims.

Claims

1. A benzothiazole derivative for detecting hydrazine, characterized in that: It has the structural formula shown in the following formula I:

2. A method for preparing a benzothiazole derivative for detecting hydrazine according to claim 1, characterized in that: The following steps are involved: (1) 2-(2-aminophenyl)benzothiazole and trifluoroacetyl chloride are reacted in pyridine solvent, and a white product ABTA is obtained after purification: (2) ABTA, acetic anhydride and nitric acid react to obtain a light yellow product ABTA-NO2 after purification: (3) Dissolve ABTA-NO2 in tetrahydrofuran, add a catalyst, react under hydrogen, and purify to obtain the product ABTA-NH2: (4) ABTT-NH2, acetic acid, and phthalic anhydride react and purify to obtain the target molecular probe ABTAP:

3. The method for preparing a benzothiazole derivative for detecting hydrazine according to claim 2, characterized in that: In the reaction of ABTA, acetic anhydride and nitric acid in step (2), ABTA and acetic anhydride are stirred in a water bath at 40-60° C., and a glacial acetic acid solution containing nitric acid is slowly added to the reaction system using a microinjection pump, and stirring in a water bath at 40-60° C. is continued until the reaction is completed.

4. The method for preparing a benzothiazole derivative for detecting hydrazine according to claim 3, characterized in that: The addition rate of the glacial acetic acid solution containing nitric acid is 0.08-0.12 mL / min.

5. The method for preparing a benzothiazole derivative for detecting hydrazine according to claim 4, characterized in that: The addition rate of the glacial acetic acid solution containing nitric acid is 0.1 mL / min.

6. The method for preparing a benzothiazole derivative for detecting hydrazine according to claim 2, characterized in that: The catalyst in step (3) is 10% Pd / C.

7. An application of the benzothiazole derivative for detecting hydrazine according to claim 1, characterized in that: Used to detect the hydrazine content in water.

8. A kit for detecting hydrazine, characterized in that: The kit comprises a benzothiazole derivative shown in formula I.

9. The kit for detecting hydrazine as claimed in claim 8, characterized in that: The concentration of the benzothiazole derivative in the kit is 5 μM to 20 μM.

10. The kit for detecting hydrazine according to claim 8, characterized in that: The kit also contains PBS buffer solution (0.01 M, pH=7.4).

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