Preparation Method and Application of an 8-Formyl-7-Hydroxy-4-Methylcoumarin Derivative

Abstract

Preparation method and application of an 8-formyl-7-hydroxy-4-methylcoumarin derivative, relating to the field of analytical detection, in particular to a preparation method of a coumarin Schiff base derivative and fluorescence relay recognition of zinc ions and glyphosate, which can solve the deficiencies of poor method reproducibility and inability to visualize under natural light in existing zinc ion and glyphosate detection methods. The preparation method of the coumarin derivative in the present invention is: obtained by condensation reaction of 8-formyl-7-hydroxy-4-methylcoumarin and benzothiazole-2-carbohydrazide under liquid phase conditions. After the coumarin derivative prepared in the present invention detects zinc ions and forms a complex in a DMF / HEPES (v / v = 9:1, pH = 7.4) solution, an in-situ reaction with glyphosate realizes the "off-on-off" relay recognition of zinc ions and glyphosate. This detection process has the advantages of fast response speed, good reproducibility, and visualization under natural light. The present invention is used in the field of relay detection of zinc ions and glyphosate.

Description

Technical Field

[0001] The present invention relates to the field of detection of zinc ions and glyphosate, and particularly to a preparation method of an 8-formyl-7-hydroxy-4-methylcoumarin derivative and its application in the detection of zinc ions and glyphosate. Background Art

[0002] Zinc is one of the relatively abundant elements in the earth's crust and often exists in the form of sulfide in nature. Since it participates in the synthesis of various enzymes in animals and plants, zinc is one of the essential trace elements for animals and plants. The largest use of zinc in modern industry is in the galvanizing industry, which is mainly used for the surface coating of steel and steel structures, such as automobiles, buildings, light industry, and ships. It is precisely the wide application of zinc in all walks of life that makes more and more zinc accumulate in animals and plants through the food chain and other effects. There is literature proving that excessive zinc ions in the human body can not only cause neurotoxicity, but also cause symptoms such as nausea, vomiting, diarrhea, and fever, causing upper abdominal pain, listlessness, and even acute renal failure. Therefore, it is of great significance to achieve rapid, convenient, and accurate quantitative and qualitative detection of zinc ions.

[0003] Glyphosate, as a non-selective herbicide, has rapidly occupied the herbicide market with excellent herbicidal performance and low price after being commercialized in 1974. However, the high solubility of glyphosate in water makes the excessive use of glyphosate quickly migrate into the soil and water sources, resulting in the pollution of the soil and water areas near farmland and accumulating in animals and plants, causing damage to the liver and kidneys, digestive tract, skin and mucous membranes, respiratory and cardiovascular systems, etc., thus threatening the health of humans and animals. In 2015, the International Agency for Research on Cancer (IARC) of the World Health Organization defined glyphosate as a possible human carcinogen. At the same time, the maximum limit of glyphosate in the EU drinking water standard is 0.1 μg / L. Therefore, the detection of glyphosate is particularly important.

[0004] The currently adopted chromatographic method and chromatographic-mass spectrometric method meet the requirements of glyphosate detection to a certain extent, but there are still problems such as cumbersome detection operations, long time consumption, high cost, and difficulty in achieving high-throughput detection. In particular, there is little research on the rapid identification and visualization detection technology of glyphosate. Compared with traditional analytical detection methods, fluorescence analysis has been applied in the detection fields of ions, active substances, biological small molecules, etc. due to its advantages of simple operation, rapid response, visualization, and on-site detection.

[0005] The basic structure of coumarin and its derivatives is composed of a benzene ring and a pyrone ring, which is of great significance in natural products and organic synthesis. At the same time, due to the advantages of low fluorescence quantum yield, easy modification, and low cytotoxicity to biological cells, coumarin compounds are widely used in the construction of fluorescent probes. In this invention, coumarin is designed as the fluorescent group, and nitrogen, oxygen, and sulfur atoms are introduced into the coumarin structure through an aldehyde group as the linking group to prepare coumarin derivative fluorescent probes. This derivative can achieve rapid and visual detection of zinc ions and glyphosate in the DMF / HEPES system, with stable performance and good reproducibility of the method. Summary of the Invention

[0006] The present invention aims to solve the deficiencies in the existing detection methods for zinc ions and glyphosate, such as poor reproducibility of the method and inability to visualize under natural light, and provides a convenient and on-site detection method for zinc ions and glyphosate.

[0007] An 8-formyl-7-hydroxy-4-methylcoumarin derivative in the present invention, the molecular structure of the coumarin derivative is as follows:

[0008]

[0009] The synthesis route of the above coumarin derivative is as follows:

[0010]

[0011] A preparation method of an 8-formyl-7-hydroxy-4-methylcoumarin derivative in the present invention includes the following steps: obtained by condensation reaction of 8-formyl-7-hydroxy-4-methylcoumarin and benzothiazole-2-carbohydrazide under liquid phase conditions.

[0012] Application of the coumarin derivative of the present invention in the detection of zinc ions and glyphosate.

[0013] Preferably, when the coumarin derivative relays to detect zinc ions and glyphosate, a visual change of "colorless - yellow - colorless" appears in the solution color under natural light.

[0014] Preferably, the fluorescence intensity does not change after cyclic detection of zinc ions and glyphosate for more than 6 times.

[0015] Principle of the present invention:

[0016] The coumarin derivative prepared in the present invention has stable properties. Multiple oxygen, nitrogen, and sulfur atoms in the structure can quickly complex with zinc ions to form a complex, resulting in fluorescence generation, thereby realizing the detection of zinc ions. Due to the strong complexation between glyphosate and zinc ions, based on the ligand substitution principle, glyphosate can "take" zinc ions from the complex system, making the derivative free, thereby causing fluorescence quenching. Based on this, the relay recognition of zinc ions and glyphosate is achieved.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1) The coumarin derivative prepared by the present invention can achieve relay visual recognition of zinc ions and glyphosate, and a visual change of "colorless - yellow - colorless" in the solution color appears under natural light during the detection process. Compared with the prior art, the present invention can achieve on-site detection of glyphosate.

[0019] 2) The coumarin derivative prepared by the present invention has stable performance, and can achieve cyclic detection of zinc ions and glyphosate more than 6 times in a neutral environment, and the fluorescence intensity does not change. This detection method has good reproducibility. Description of the Drawings

[0020] Figure 1 Coumarin derivative 1 1H NMR spectrum;

[0021] Figure 2 FT-IR spectrum of coumarin derivative;

[0022] Figure 3 Fluorescence selectivity of coumarin derivative for recognizing metal ions;

[0023] Figure 4 Effect of coexisting metal ions on the detection of zinc ions by coumarin derivative;

[0024] Figure 5 Linear relationship diagram of fluorescence response of coumarin derivative to different concentrations of zinc ions;

[0025] Figure 6 Job’s plot curve of coumarin derivative for zinc ions;

[0026] Figure 7 Fluorescence selectivity of the complex of coumarin derivative and zinc ions for recognizing organophosphorus pesticides;

[0027] Figure 8 Effect of coexisting organophosphorus pesticides on the detection of glyphosate by the complex of coumarin derivative and zinc ions;

[0028] Figure 9 Linear relationship diagram of fluorescence response of the complex of coumarin derivative and zinc ions to different concentrations of glyphosate;

[0029] Figure 10 Job’s plot curve of the complex of coumarin derivative and zinc ions for glyphosate;

[0030] Figure 11 Color change of the solution of coumarin derivative for relay recognition of zinc ions and glyphosate under natural light;

[0031] Figure 12 Coumarin derivative relay recognition of zinc ions and glyphosate cycle curve graph; Specific implementation manners

[0032] The technical solution of the present invention is not limited to the specific implementation manners listed below, and also includes any combination between the specific implementation manners.

[0033] Specific implementation manner one: An 8-formyl-7-hydroxy-4-methylcoumarin derivative, the molecular structure of which is:

[0034]

[0035] Specific implementation manner two: A preparation method of an 8-formyl-7-hydroxy-4-methylcoumarin derivative is as follows: 8-formyl-7-hydroxy-4-methylcoumarin and benzothiazole-2-carbohydrazide are subjected to a condensation reaction under liquid phase conditions to obtain.

[0036] Specific implementation manner three: Application of the coumarin derivative in the detection of zinc ions and glyphosate.

[0037] Specific implementation manner four: The difference between this implementation manner and the third implementation manner is that: the method for the coumarin derivative to detect zinc ions and glyphosate is: after the derivative detects zinc ions and forms a complex, an in-situ reaction with glyphosate is carried out to realize the "off-on-off" relay recognition of zinc ions and glyphosate.

[0038] Specific implementation manner five: The difference between this implementation manner and the fourth implementation manner is that: when the coumarin derivative relays to detect zinc ions and glyphosate, a visual change of "colorless - yellow - colorless" appears in the solution color under natural light. Others are the same as the fourth implementation manner.

[0039] Specific implementation manner six: The difference between this implementation manner and the fourth or fifth implementation manner is that: the fluorescence intensity does not change after the derivative cycles to detect zinc ions and glyphosate more than 6 times. Others are the same as the fourth or fifth implementation manner.

[0040] The following makes a detailed description of the embodiments of the present invention. The following embodiments are implemented on the premise of the technical solution of the present invention, and detailed implementation schemes and specific operation processes are given, but the protection scope of the present invention is not limited to the following embodiments.

[0041] Example 1: The preparation method of the coumarin derivative in this example is carried out according to the following steps:

[0042] In a 50 mL three-necked flask, 8-formyl-7-hydroxy-4-methylcoumarin (0.193 g, 1 mmol) and benzothiazole-2-carbohydrazide (0.204 g, 1 mmol) were added, along with 30 mL of ethanol and a little catalytic amount of glacial acetic acid. After refluxing for 6 h, the mixture was cooled to precipitate a pale yellow solid. After suction filtration, washing, and drying, a coumarin derivative (0.306 g, 0.77 mmol) was obtained with a yield of 76.9%. 1H NMR (300 MHz, DMSO-d6) δ 13.41 (s, 1H), 12.68 (s, 1H), 9.42 (s, 1H), 8.29 (d, J = 7.8 Hz, 1H), 8.22 (d, J = 8.0 Hz, 1H), 7.76 (d, J = 9.1 Hz, 1H), 7.67 (t, J = 8.4 Hz, 2H), 7.00 (d, J = 9.0 Hz, 1H), 6.28 (s, 1H), 2.42 (s, 3H). FT-IR (KBr): 3224.65, 2830.68, 1730.38, 1683.80, 1610.20, 1540.36, 1489.55, 1366.51, 1319.58, 1093.02, 774.32. The 1H NMR and IR spectra of the coumarin derivative are as shown in Figure 1 and 2 shown

[0043] Example 2: The fluorescence recognition performance of the coumarin derivative for metal ions in this example was carried out according to the following steps:

[0044] Each time, 3 mL of a coumarin derivative solution with a concentration of 1×10 -5 mol / L (DMF / HEPES, v / v = 9:1, pH = 7.4) was taken in a cuvette, and 3 equivalents of Ag + , Ba 2+ , Bi 3+ , Ca 2+ , Cd 2+ , Co 3+ , Cs 2+ , Pb 2+ , Fe 3+ , Hg 2+ , K + , Li + , Mg 2+ , Na + , Cu 2+ aqueous solutions were added in sequence. Under the action of an excitation light at 434 nm, the fluorescence emission peak intensity value at 513 nm was measured, and the results are as shown in Figure 3 shown. After adding Zn 2+ to the coumarin derivative, there was an obvious fluorescence enhancement effect, and the fluorescence intensity increased from 138.7 A.U. to 2621 A.U., an increase of about 20 times; after adding Al3+ After that, the fluorescence appeared slightly enhanced, about 5-fold, which was weaker than that in the presence of zinc ions; while the addition of other metal ions did not cause obvious fluorescence changes. The above changes indicate that the coumarin derivative exhibits specific fluorescence recognition towards zinc ions.

[0045] Example 3: The interference resistance of the coumarin derivative in recognizing zinc ions against other metal ions was carried out according to the following steps:

[0046] Each time, 3 mL of the coumarin derivative solution was taken in a cuvette, and 3 equivalents of Ag + , Ba 2+ , Bi 3+ , Ca 2+ , Cd 2+ , Co 3+ , Cs 2+ , Pb 2+ , Fe 3+ , Hg 2+ , K + , Li + , Mg 2+ , Na + , Cu 2+ aqueous solutions were added in sequence. Under the action of the excitation light at 434 nm, the fluorescence emission peak intensity value at 513 nm was measured. Then 3 equivalents of Zn 2+ were added in sequence, and the fluorescence intensity changes were observed and recorded. The results are shown in Figure 4. When copper ions coexist with zinc ions, it will cause fluorescence quenching of the detection system; when cobalt ions coexist with zinc ions, the fluorescence intensity quenches by nearly 70%; in the case of the coexistence of other metal ions, the fluorescence intensity of the system changes little. Except for copper ions and cobalt ions, this coumarin derivative can resist the interference of various metal ions in the process of recognizing zinc ions.

[0047] Example 4: The detection limit of the coumarin derivative for zinc ions was carried out according to the following steps:

[0048] Take 3 mL of the coumarin derivative solution, and each time add 3 μL of zinc ion aqueous solution with a concentration of 1×10 -3 mol / L, and measure the fluorescence intensity changes. The results are shown in Figure 5 . As the concentration of zinc ions in the system increases, the fluorescence intensity of the coumarin derivative gradually increases. When the concentration of zinc ions in the system reaches 10 μM, the fluorescence intensity hardly changes. When the zinc ion concentration is within 1 μM - 8 μM, the fluorescence intensity shows a good linear relationship with the zinc ion concentration, and the fitting equation is y = 260.28x + 324.38, R 2 = 0.992. According to the calculation formula of the detection limit 3σ / k, the detection limit of the coumarin derivative for zinc ions is calculated to be 7.35×10 - 8mol / L. This probe can achieve trace detection of zinc ions.

[0049] Example 5: The complexation ratio of the coumarin derivative with zinc ions in this example was carried out as follows:

[0050] Take a coumarin derivative solution with a concentration of 1.0×10 -5 mol / L and an aqueous zinc ion solution of 1×10 -3 mol / L. Keep the total concentration of the coumarin derivative and zinc ions in the system unchanged at 1×10 -5 mol / L. By changing the equivalent ratio of the coumarin derivative and zinc ions, measure the change in the fluorescence emission peak intensity, and plot the Job’s Plot curve. The results are as Figure 6 shown. It can be analyzed from the Job’s Plot curve that when the mole fraction of zinc ions is 0.54, the fluorescence intensity shows an inflection point, indicating that the complexation ratio of the coumarin derivative with zinc ions is 1:1.

[0051] Example 6: The fluorescence selectivity of the coumarin derivative-zinc ion complex for the recognition of organophosphorus pesticides was carried out as follows:

[0052] Each time, take 3 mL of the coumarin derivative solution in a cuvette, add 1 eq. of the zinc ion solution, and incubate for 1 - 3 s to obtain the complex coumarin-zinc ion system. Then add 3 eq. of glyphosate, trichlorfon, phosmet, dichlorvos, malathion, omethoate, dimethoate, ethoprophos, fenitrothion, methyl parathion, parathion, and glufosinate-ammonium in sequence. Under the action of the excitation light at 434 nm, measure the fluorescence emission peak intensity value at 513 nm. The results are as Figure 7 shown. When glyphosate is added, the fluorescence of the system is significantly quenched, while when other pesticides are added, the fluorescence intensity does not change significantly. The coumarin derivative-zinc ion complex system realizes the specific recognition of glyphosate.

[0053] Example 7: The anti-interference ability of the coumarin derivative-zinc ion complex for the recognition of glyphosate was carried out as follows:

[0054] In the coumarin-zinc ion complex system, add 3 eq. of trichlorfon, phosmet, dichlorvos, malathion, omethoate, dimethoate, ethoprophos, fenitrothion, methyl parathion, parathion, and glufosinate-ammonium in sequence. Under the action of the excitation light at 434 nm, measure the fluorescence emission peak intensity value at 513 nm. Then add 3 eq. of glyphosate in sequence, and observe and record the change in fluorescence intensity. The results are as Figure 8 shown. In the presence of other coexisting pesticides, the fluorescence quenching phenomenon appears in the detection system after adding glyphosate, indicating that other pesticides have no interference on the recognition of glyphosate by the coumarin derivative-zinc ion complex system.

[0055] Example 8: Detection limit of coumarin derivative zinc ion complex for glyphosate is carried out according to the following steps:

[0056] In the coumarin-zinc ion complex system, 3 μL of glyphosate aqueous solution with a concentration of 1×10 -3 mol / L is added each time, and the fluorescence intensity is measured. The results are as Figure 9 shown. As the glyphosate concentration in the system increases, the fluorescence intensity of the complex coumarin-zinc ion gradually decreases. When the glyphosate concentration in the system reaches 10 μM, the fluorescence intensity hardly changes. When the glyphosate concentration is within 1 μM - 8 μM, the fluorescence intensity shows a good linear relationship with the glyphosate concentration. The fitting equation is y = -297.51x + 2513.01, and R 2 = 0.994. According to the detection limit calculation formula 3σ / k, the detection limit of the coumarin derivative for glyphosate is calculated to be 4.59×10 -8 mol / L, realizing the trace detection of glyphosate.

[0057] Example 9: Interaction ratio of coumarin derivative zinc ion complex for glyphosate is carried out according to the following steps:

[0058] Take a coumarin derivative zinc ion complex solution with a concentration of 1.0×10 -5 mol / L and a glyphosate aqueous solution with a concentration of 1×10 -3 mol / L, and keep the total concentration in the system at 1×10 -5 mol / L unchanged. By changing the equivalent ratio of the two, the change in the fluorescence emission peak intensity is measured, and a Job’s Plot curve is drawn. The results are as Figure 10 shown. It can be analyzed from the Job’s Plot curve that when the mole fraction of glyphosate is 0.49, the fluorescence intensity shows an inflection point, indicating that the complex ratio of the coumarin derivative zinc ion complex to glyphosate is 1:1.

[0059] Example 10: Solution color change of coumarin derivative for relay recognition of zinc ion and glyphosate under daylight lamp is carried out according to the following steps:

[0060] Take 6 mL of coumarin derivative solution in a vial. Add 1 equivalent of zinc ion aqueous solution to vials 2# and 3#. After incubating for 1 - 3 s, add 1 equivalent of glyphosate to vial 3# and observe under daylight lamp. The results are as Figure 11 shown. It can be seen from the results that the coumarin derivative can achieve relay visual recognition in the process of detecting zinc ion and glyphosate, and a visual change of "colorless - yellow - colorless" occurs in the solution under natural light during the detection process. Realize the on-site and instant detection of zinc ion and glyphosate.

[0061] Example 11: Performance test of the cyclic recognition of zinc ions and glyphosate by coumarin derivatives was carried out according to the following steps:

[0062] Take 3 mL of coumarin derivative solution in a cuvette, add 1.5 equivalents of zinc ion aqueous solution, and after incubating for 1 - 3 s, under the action of 434 nm excitation light, measure the fluorescence emission peak intensity value at 513 nm. Then add 1.5 equivalents of glyphosate aqueous solution, and after incubating for 1 - 3 s, under the action of 434 nm excitation light, measure the fluorescence emission peak intensity value at 513 nm. Repeat the above operation 6 times, and draw the fluorescence curve of the cyclic recognition of zinc ions and glyphosate by coumarin derivatives. The results are as Figure 12 shown. From the results of the cyclic experiment, it can be seen that the coumarin derivative can achieve the fluorescence "off-on-off" relay recognition of zinc ions and glyphosate, and the performance is stable. The fluorescence intensity does not change after more than 6 cycles of detection. This shows that the detection method has good reproducibility and has practical application prospects.

Claims

1. An 8-formyl-7-hydroxy-4-methylcoumarin derivative, characterized in that the molecular structure of the derivative is:

2. The preparation method of an 8-formyl-7-hydroxy-4-methylcoumarin derivative according to claim 1, characterized in that the method is: 8-formyl-7-hydroxy-4-methylcoumarin is condensed with benzothiazole-2-carbohydrazide under liquid phase conditions to obtain.

3. The application of the coumarin derivative according to claim 1 in the preparation of a reagent for relay detection of zinc ions and glyphosate.

4. The application according to claim 3, characterized in that after the coumarin derivative detects zinc ions and forms a complex, it reacts in situ with glyphosate to achieve "off-on-off" relay recognition of zinc ions and glyphosate.

5. The application according to claim 4, characterized in that when the coumarin derivative relays the detection of zinc ions and glyphosate, a visual change of "colorless-yellow-colorless" appears in the solution color under natural light.

6. The application according to claim 4, characterized in that the coumarin derivative has stable performance, good method reproducibility, and the fluorescence intensity does not change after cyclic detection of zinc ions and glyphosate more than 6 times.

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