A camphor-based fluorescent probe for detecting the organophosphorus pesticide dimethoate, and its preparation method and application
By preparing a new camphor-based fluorescent probe CPA-OAc and utilizing the enzyme inhibition principle to detect dimethoate under ultraviolet light, the problems of the existing detection methods being complex and insensitive were solved, and rapid and sensitive dimethoate detection was achieved.
Patent Information
- Application Number
- CN202410946430.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-15
- Publication Date
- 2025-09-26
- Estimated Expiration
- 2044-07-15
AI Technical Summary
Existing methods for detecting dimethoate have the disadvantages of expensive instruments, cumbersome sample pretreatment, time-consuming detection and complicated operation. In addition, existing fluorescent probes are complex to synthesize, have high biological toxicity and poor dispersibility, making it difficult to achieve rapid and sensitive dimethoate detection.
A new camphor-based fluorescent probe CPA-OAc was developed and prepared through Claisen condensation, cyclization, Suzuki coupling, aldol condensation and esterification. The enzyme inhibition principle was used to detect dimethoate under 375 nm ultraviolet light, and the fluorescence color change was specific.
The rapid and sensitive detection of dimethoate is achieved with a detection range of 0 to 25 mg/L and a detection limit as low as 110.4 μg/L. It is easy to synthesize and has good selectivity, making it suitable for the detection of dimethoate residues in agricultural products and biological systems.
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Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of fine organic synthesis and relates to a novel camphor-based fluorescent probe for detecting the organophosphorus pesticide dimethoate, and a preparation method and application thereof. Background Art
[0002] The widespread use of pesticides can effectively ensure high-yield and high-quality crops, thereby contributing to the rapid improvement of agricultural production. Organophosphorus pesticides, as a class of highly effective, broad-spectrum insecticides and fungicides, have been widely used in crop management and agricultural production to control pests, weeds, and bacteria. Dimethoate is a widely used organophosphorus pesticide and plays an important role in the cultivation of vegetables and fruits. However, excessive use of dimethoate can lead to food toxicity and environmental degradation, posing significant risks to human health. Excessive intake of dimethoate can cause a range of serious diseases, including neurotoxicity, immune system damage, and endocrine disorders. In particular, excessive dimethoate can cause severe damage to liver and kidney metabolism, thereby affecting the clearance of some toxic substances from the body. Therefore, it is necessary to develop an effective and rapid method to sensitively detect dimethoate residues in agricultural products and biological systems.
[0003] Currently, analytical techniques for detecting dimethoate include high-performance liquid chromatography, gas chromatography-mass spectrometry, electrophoresis, thin-layer chromatography, and electrochemical analysis. However, the application of these techniques for real-time detection is limited by expensive instrumentation, cumbersome sample pretreatment, time-consuming detection, and complex operating procedures. In recent years, fluorescent probes have been widely used in medical diagnosis, environmental monitoring, bioimaging, and food analysis due to their high sensitivity and non-destructive properties. To date, there are few reports of fluorescent probes for dimethoate detection, and almost all of these probes are primarily based on nanomaterials such as CdTe / CdSe quantum dots, gold / silver nanoparticles, and carbon nanotubes. Although these probes generally have high sensitivity and selectivity, some suffer from complex synthesis, high biotoxicity, and low dispersibility in solution, resulting in poor reproducibility. Therefore, developing an analytical method for detecting dimethoate based on the principle of enzyme inhibition and fluorescent probe technology is both important and challenging. Summary of the Invention
[0004] In view of the deficiencies in the prior art, the technical problem to be solved by the present invention is to provide a new camphor-based fluorescent probe for detecting the organophosphorus pesticide dimethoate, which can meet the usage requirements.
[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is:
[0006] A new camphor-based fluorescent probe for detecting the organophosphorus pesticide dimethoate has the structural formula:
[0007]
[0008] The molecular formula of this fluorescent probe is C 39 H 33 N3O4, the compound name is 3-oxo-2-(4′-(7,8,8-trimethyl-3-(pyridin-4-yl)-4,5,6,7-tetrahydro-2H-4,7-oxomethyleneindazol-2-yl)-[1,1′-diphenyl]-4-yl)methenyl)-2,3-dihydrobenzofuran-6-yl acetate, abbreviated as CPA-OAc.
[0009] The method for preparing a novel camphor-based fluorescent probe for detecting the organophosphorus pesticide dimethoate comprises the following steps:
[0010] (1) Camphor is used as a raw material and subjected to Claisen condensation with ethyl isonicotinate to obtain 3-(pyridine-4-formyl)-1,7,7-trimethylbicyclo[2.2.1]2-heptanone.
[0011] (2) 3-(Pyridine-4-formyl)-1,7,7-trimethylbicyclo[2.2.1]2-heptanone is further cyclized with 4-bromophenylhydrazine to obtain 2-(4-bromophenyl)-7,8,8-trimethyl-3-(pyridin-4-yl)-4,5,6,7-tetrahydro-2H-4,7-methanoindazole.
[0012] (3) 2-(4-bromophenyl)-7,8,8-trimethyl-3-(pyridin-4-yl)-4,5,6,7-tetrahydro-2H-4,7-methanoindazole was subjected to Suzuki coupling reaction with 4-formylphenylboronic acid to prepare 4′-(7,8,8-trimethyl-3-(pyridin-4-yl)-4,5,6,7-tetrahydro-2H-4,7-methanoindazole-2-yl)-[1,1′-diphenyl]-4-carbaldehyde compound.
[0013] (4) 4′-(7,8,8-trimethyl-3-(pyridin-4-yl)-4,5,6,7-tetrahydro-2H-4,7-methyleneindazol-2-yl)-[1,1′-diphenyl]-4-carbaldehyde is then subjected to an aldol condensation reaction with 6-hydroxy-2H-benzofuran-3-one to obtain (Z)-6-hydroxy-2-((4′-(7,8,8-trimethyl-3-(pyridin-4-yl)-4,5,6,7-tetrahydro-2H-4,7-methyleneindazol-2-yl)-[1,1′-diphenyl]-4-yl)methylene)benzofuran-3(2H)-one (abbreviated as: CPA-OH).
[0014] (5) CPA-OH reacts with acetyl chloride to produce CPA-OAc.
[0015] The synthesis steps of 3-(pyridine-4-formyl)-1,7,7-trimethylbicyclo[2.2.1]2-heptanone in step (1) are as follows:
[0016] 1) Under nitrogen protection, 2.4-3 g (100-125 mol) of 60% sodium hydrogen and 50-60 mL of ethylene glycol dimethyl ether were added to a 250 mL three-necked flask equipped with a stirrer and a reflux condenser, and stirred for 20-30 min; 3.04-3.81 g (20-25 mmol) of camphor was dissolved in 20-30 mL of ethylene glycol dimethyl ether and slowly added dropwise to the reaction flask using a constant pressure dropping funnel, and the mixture was reacted under reflux for 1.5-2 h; then 3.02-3.78 g (20-25 mmol) of ethyl isonicotinate was dissolved in 20-30 mL of ethylene glycol dimethyl ether and slowly added dropwise to the reaction flask for 5-7 h.
[0017] 2) After the reaction solution was distilled off under reduced pressure to remove ethylene glycol dimethyl ether, 100-200 mL of ethyl acetate was added to dissolve the distillation residue, which was then washed with distilled water until neutral, then washed with saturated brine, dried over anhydrous sodium sulfate, and distilled to obtain 3-(pyridine-4-formyl)-1,7,7-trimethylbicyclo[2.2.1]2-heptanone.
[0018] The synthesis steps of 2-(4-bromophenyl)-7,8,8-trimethyl-3-(pyridin-4-yl)-4,5,6,7-tetrahydro-2H-4,7-methanoindazole in step (2) are as follows:
[0019] 1) To a 100 mL single-necked flask equipped with a stirrer and a reflux condenser, add 2.57-2.83 g (1-1.1 mmol) of 3-(pyridine-4-carbonyl)-1,7,7-trimethylbicyclo[2.2.1]2-heptanone, 40-60 mL of ethanol, and 3.74-3.93 g (2-2.1 mmol) of 4-bromophenylhydrazine. Then, add 3-5 drops of acetic acid and stir under reflux at 80°C for 24 h.
[0020] 2) The reaction solution was filtered and washed thoroughly with ethanol, and the resulting solid was dried under vacuum at 45° C. for 24 to 36 hours to obtain 2-(4-bromophenyl)-7,8,8-trimethyl-3-(pyridin-4-yl)-4,5,6,7-tetrahydro-2H-4,7-dimethanoindazole.
[0021] The synthesis steps of 4′-(7,8,8-trimethyl-3-(pyridin-4-yl)-4,5,6,7-tetrahydro-2H-4,7-endomethylindazol-2-yl)-[1,1′-diphenyl]-4-carbaldehyde in step (3) are as follows:
[0022] 1) Under nitrogen protection, to a 100 mL three-necked flask equipped with a stirrer and a reflux condenser were added 2.04-2.45 g (0.5-0.6 mmol) of 2-(4-bromophenyl)-7,8,8-trimethyl-3-(pyridin-4-yl)-4,5,6,7-tetrahydro-2H-4,7-methanoindazole, 1.5-1.8 g (1-1.2 mmol) of 4-formylphenylboronic acid, 0.06-0.07 g (0.05-0.06 mmol) of Pd(PPh3)4, and 5-6 mL of a 1 M K2CO3 aqueous solution. 50-60 mL of a 1,4-dioxane / water (v / v=5 / 1) mixed solvent was then added, and the reaction was refluxed for 24-36 h (monitored by TLC).
[0023] 2) The reaction solution was cooled to room temperature, filtered to remove the catalyst, and then distilled to remove the solvent. 30-40 mL of ethyl acetate was added to dissolve the distillation residue. The organic phase was washed with saturated brine until neutral. The solvent was evaporated to obtain a crude product. The crude product was purified by silica gel column chromatography (petroleum ether / ethyl acetate = 5 / 1, v / v) to obtain 4′-(7,8,8-trimethyl-3-(pyridin-4-yl)-4,5,6,7-tetrahydro-2H-4,7-endomethylindazol-2-yl)-[1,1′-diphenyl]-4-carbaldehyde.
[0024] The synthesis steps of CPA-OH in step (4) are as follows:
[0025] 1) To a 50 mL single-necked flask equipped with a stirrer and a reflux condenser, 0.50-0.54 g (1.15-1.25 mmol) of 4′-(7,8,8-trimethyl-3-(pyridin-4-yl)-4,5,6,7-tetrahydro-2H-4,7-endomethylindazol-2-yl)-[1,1′-diphenyl]-4-carbaldehyde, 0.17-0.19 g (1.15-1.25 mmol) of 6-hydroxy-2H-benzofuran-3-one, 15-20 mL of ethanol, and 0.092-0.1 g (2.3-2.5 mmol) of sodium hydroxide were added and reacted at 60-70°C for 1-2 h.
[0026] 2) After the reaction solution was distilled to remove ethanol, the resulting crude product was purified by silica gel column chromatography (petroleum ether / ethyl acetate = 3 / 1) to obtain compound CPA-OH.
[0027] The synthesis steps of CPA-OAc in step (5) are as follows:
[0028] 1) Under nitrogen protection, dissolve 0.28-0.34 g (0.5-0.6 mmol) of CPA-OH and 0.33-0.39 g (1-1.2 mmol) of cesium carbonate in 15-20 mL of anhydrous acetonitrile and stir for 30-40 min.
[0029] 2) Slowly add 0.16-0.20 g (2-2.5 mmol) of acetyl chloride dropwise in an ice bath, react for 1.5-2 h, then raise the temperature to reflux and continue the reaction for 2-3 h.
[0030] 3) The reaction solution was distilled to remove acetonitrile, and 15-20 mL of dichloromethane was added to dissolve the distillation residue, which was washed with saturated brine until neutral. After drying and distillation, the resulting crude product was further purified by silica gel column chromatography (petroleum ether / ethyl acetate = 1 / 1) to obtain CPA-OAc.
[0031] The compound CPA-OAc can specifically undergo enzymatic hydrolysis reaction with carboxylesterase. Under irradiation with ultraviolet light of a wavelength of 375 nm, the fluorescent color of the solution changes from colorless to green. Dimethoate can inhibit the activity of carboxylesterase. Under irradiation with a 375 nm ultraviolet lamp, the fluorescent color of the probe solution changes from green to colorless.
[0032] Beneficial Effects: Compared with existing technologies, the compound CPA-OAc of the present invention can specifically detect the organophosphorus pesticide dimethoate and can sensitively detect the dimethoate content in solution. The detection range for dimethoate is 0-25 mg / L, with a detection limit as low as 110.4 μg / L. As a fluorescent probe for detecting dimethoate, it has many advantages, including easy synthesis, good selectivity, and high sensitivity, and has promising application prospects. BRIEF DESCRIPTION OF THE DRAWINGS
[0033] Figure 1 is the fluorescence spectrum of the compound CPA-OAc after the action of different pesticides, where F and F0 are the fluorescence intensities of CPA-OAc after the action of carboxylesterase and different pesticides, respectively;
[0034] Figure 2 This is the fluorescence spectrum of the compound CPA-OAc reacting with different concentrations of dimethoate. DETAILED DESCRIPTION
[0035] The present invention will be further described below with reference to specific embodiments.
[0036] Example 1
[0037] Preparation of compound CPA-OAc
[0038] The preparation route of CPA-OAc is as follows:
[0039]
[0040] The specific steps include:
[0041] 1) Preparation of 3-(pyridine-4-carbonyl)-1,7,7-trimethylbicyclo[2.2.1]2-heptanone
[0042] Under nitrogen protection, 2.4-3 g (100-125 mol) of 60% sodium hydrogen sulfide and 50-60 mL of ethylene glycol dimethyl ether were added to a 250 mL three-necked flask equipped with a stirrer and a reflux condenser, and the mixture was stirred for 20-30 min. 3.04-3.81 g (20-25 mmol) of camphor was dissolved in 20-30 mL of ethylene glycol dimethyl ether and the mixture was slowly added dropwise to the reaction flask using a constant pressure dropping funnel. The mixture was reacted under reflux for 1.5-2 h. 3.02-3.78 g (20-25 mmol) of ethyl isonicotinate was then dissolved in 20-30 mL of ethylene glycol dimethyl ether and the mixture was slowly added dropwise to the reaction flask for 5-7 h. After the reaction solution was distilled off under reduced pressure to remove ethylene glycol dimethyl ether, 100-200 mL of ethyl acetate was added to dissolve the distillation residue, which was then washed with distilled water until neutral and then with saturated brine. The organic phase was dried over anhydrous sodium sulfate and distilled to obtain 3-(pyridine-4-formyl)-1,7,7-trimethylbicyclo[2.2.1]2-heptanone with a yield of 68% and a purity of 98.5%. 1 H NMR (600MHz, DMSO-d6) δ8.75-8.71 (m, 2H), 7.59-7.56 (m, 2H), 2.91 (d, J=3.9Hz, 1H), 2.14 (tt, J=11.8, 4.4Hz, 1H), 1.85-1. 78 (m,, 1H), 1.55 (ddd, J=12.4, 9.1, 3.7Hz, 1H), 1.43 (ddd, J=13.6, 9.2, 4.7Hz, 1H), 0.94 (s, 3H), 0.93 (s, 3H), 0.76 (s, 3H). 13 CNMR (150MHz, DMSO-d6) δ213.59, 194.94, 151.43, 150.81, 141.00, 121.95, 121.8 7, 63.56, 57.91, 49.88, 48.05, 30.46, 20.46, 19.71, 19.15, 9.20.HRMS: m / z[M+H] + calcd for C 16 H 19 NO2258.1489; found 258.1496.
[0043] 2) Preparation of 2-(4-bromophenyl)-7,8,8-trimethyl-3-(pyridin-4-yl)-4,5,6,7-tetrahydro-2H-4,7-methanoindazole
[0044] To a 100 mL single-necked flask equipped with a stirrer and a reflux condenser were added 2.57-2.83 g (1-1.1 mmol) of 3-(pyridine-4-carbonyl)-1,7,7-trimethylbicyclo[2.2.1]2-heptanone, 40-60 mL of ethanol, and 3.74-3.93 g (2-2.1 mmol) of 4-bromophenylhydrazine. 3-5 drops of acetic acid were then added dropwise, and the mixture was refluxed for 24 hours. The reaction solution was filtered and thoroughly washed with ethanol, and the resulting solid was vacuum-dried at 45° C. for 24-36 hours to obtain 2-(4-bromophenyl)-7,8,8-trimethyl-3-(pyridin-4-yl)-4,5,6,7-tetrahydro-2H-4,7-methanoindazole in a yield of 51% and a purity of 99.1%. 1 H NMR (600MHz, DMSO-d6) δ 8.57-8.54 (m, 2H), 7.63-7.60 (m, 2H), 7.47-7.44 (m, 2H), 7.42-7.39 (m, 2H), 6.96 (s, 1H), 2.29 (t, J=4.7Hz, 1H) , 1.42 (ddd, J=16.3, 9.5, 3.5Hz, 1H), 1.28 (td, J=12.6, 4.5Hz, 1H), 1.21 (s, 3H), 1.12 (dt, J=8.3, 4.1Hz, 1H), 1.09 (s, 3H), 0.89 (s, 3H). 13 C NMR (150MHz, DMSO-d6) δ150.52, 145.87, 142.83, 140.08, 131.72, 119.47, 118.49, 112.23, 104.99, 61.00, 55.13, 51.86, 47.04, 30.96, 21.36, 20.86.HRMS: m / z[M+H] + calcd for C 22 H 22 BrN3408.1070; found 408.1067.
[0045] 3) Preparation of 4′-(7,8,8-trimethyl-3-(pyridin-4-yl)-4,5,6,7-tetrahydro-2H-4,7-methanoindazol-2-yl)-[1,1′-diphenyl]-4-carbaldehyde
[0046] Under nitrogen protection, to a 100 mL three-necked flask equipped with a stirrer and a reflux condenser were added 2.04-2.45 g (0.5-0.6 mmol) of 2-(4-bromophenyl)-7,8,8-trimethyl-3-(pyridin-4-yl)-4,5,6,7-tetrahydro-2H-4,7-methanoindazole, 1.5-1.8 g (1-1.2 mmol) of 4-formylphenylboronic acid, 0.06-0.07 g (0.05-0.06 mmol) of Pd(PPh3)4 and 5-6 mL of 1 M K2CO3 aqueous solution, and then 50-60 mL of a mixed solvent of 1,4-dioxane / water (v / v=5 / 1) was added, and the reaction was refluxed for 24-36 h (monitored by TLC). The reaction solution was cooled to room temperature, filtered to remove the catalyst, and then distilled to remove the solvent. 30-40 mL of ethyl acetate was added to dissolve the distillation residue. The organic phase was washed with saturated brine until neutral. The solvent was distilled off to obtain a crude product. The crude product was purified by silica gel column chromatography (petroleum ether / ethyl acetate = 5 / 1, v / v) to obtain 4'-(7,8,8-trimethyl-3-(pyridin-4-yl)-4,5,6,7-tetrahydro-2H-4,7-endomethylindazol-2-yl)-[1,1'-diphenyl]-4-carbaldehyde with a yield of 81% and a purity of 99.7%. 1 H NMR (600MHz, DMSO-d6) δ10.02 (s, 1H), 8.63-8.52 (m, 2H), 7.98-7.94 (m, 2H), 7. 90 (d, J=8.4Hz, 2H), 7.75-7.73 (m, 2H), 7.65 (t, J=7.2Hz, 4H), 3.97 (dd, J=5.1, 1.6Hz, 1H), 2.32 (t, J=4.7Hz, 1H), 1.45 (td, J=12.5, 12.0, 5.9Hz, 1H), 1.31 (td , J=12.4, 4.3Hz, 1H), 1.24 (s, 3H), 1.20-1.17 (m, 1H), 1.16 (s, 3H), 0.91 (s, 3H). 13 C NMR (150MHz, DMSO-d6) δ193.94, 192.95, 150.46, 146.08, 146.06, 144.00, 140.16, 135.03, 134.71, 130.67, 130.49, 128.76 , 127.82, 126.64, 119.52, 116.97, 105.17, 60.99, 55.19, 31.43, 31.02, 22.54, 22.31, 21.41, 14.44, 13.79.HRMS: m / z[M+H] + calcd for C 29 H 27N3O 434.2227; found 434.2227.
[0047] 4) Preparation of CPA-OH
[0048] 1) To a 50 mL single-necked flask equipped with a stirrer and a reflux condenser were added 0.50-0.54 g (1.15-1.25 mmol) of 4′-(7,8,8-trimethyl-3-(pyridin-4-yl)-4,5,6,7-tetrahydro-2H-4,7-methanoindazol-2-yl)-[1,1′-diphenyl]-4-carbaldehyde, 0.17-0.19 g (1.15-1.25 mmol) of 6-hydroxy-2H-benzofuran-3-one, 15-20 mL of ethanol, and 0.092-0.1 g (2.3-2.5 mmol) of sodium hydroxide, and the mixture was reacted at 60-70° C. for 1-2 h. After removing ethanol from the reaction solution by distillation, the resulting crude product was purified by silica gel column chromatography (petroleum ether / ethyl acetate = 3 / 1) to obtain compound CPA-OH with a yield of 50% and a purity of 99.3%. 1 H NMR (600MHz, DMSO-d6) δ11.26 (s, 1H), 8.62-8.55 (m, 2H), 8.10-8.05 (m, 2H), 7.97-7.87 (m, 5H), 7.86-7.81 (m, 2H), 7.65 (d, J=8.4Hz, 1H), 7.13-7.08 (m, 2H), 6.86 (s, 1H), 6.74 (dd, J=8.4, 2.0H z, 1H), 3.89 (d, J=4.3Hz, 1H), 2.28 (tt, J=12.1, 4.6Hz, 1H), 1.87-1.80 (m, 1H), 1.68 (ddd, J=12. 9, 9.3, 4.1Hz, 1H), 1.49 (td, J=9.0, 4.6Hz, 1H), 1.07 (s, 3H), 0.97 (d, J=1.7Hz, 3H), 0.90 (s, 3H). 13 C NMR (150MHz, DMSO-d6) δ168.30, 150.55, 147.70, 145.75, 143.54, 141.30 , 140.15, 132.21, 131.07, 130.70, 127.33, 126.57, 126.43, 119.44, 117. 02, 113.55, 113.37, 110.84, 105.13, 99.13, 60.98, 55.18, 51.87, 47.07, 31.43, 31.02, 22.54, 22.30, 21.40, 20.90, 14.43, 13.79.HRMS: m / z[M+H] + calcd for C37 H 31 N3O3566.2438; found 566.2441.
[0049] 5) Preparation of CPA-OAc
[0050] Under nitrogen protection, 0.28-0.34 g (0.5-0.6 mmol) of CPA-OH and 0.33-0.39 g (1-1.2 mmol) of cesium carbonate were dissolved in 15-20 mL of anhydrous acetonitrile and stirred for 30-40 min. 0.16-0.20 g (2-2.5 mmol) of acetyl chloride was slowly added dropwise under an ice bath, and the reaction was continued for 1.5-2 h before the temperature was raised to reflux and the reaction was continued for 2-3 h. The acetonitrile was removed from the reaction solution by distillation, and 15-20 mL of dichloromethane was added to dissolve the distillation residue, which was washed with saturated brine until neutral. After drying and distillation, the crude product was further purified by silica gel chromatography (petroleum ether / ethyl acetate = 1 / 1) to obtain CPA-OAc with a yield of 35% and a purity of 98.9%. 1 H NMR (600MHz, DMSO-d6) δ8.63-8.58 (m, 2H), 8.11 (d, J=8.2Hz, 2H), 7.97-7.88 (m, 4H), 7.8 7(d, J=8.3Hz, 1H), 7.77-7.72 (m, 2H), 7.67 (d, J=8.3Hz, 2H), 7.50 (d, J=1.8Hz, 1H), 7.12 (dd, J=8.3, 1.9Hz, 1H), 7.03 (s, 1H), 2.35 (s, 3H), 2.19 (tt, J=8.8, 4.3Hz, 1H), 1.92 (dt, J=12.5, 4.8Hz, 1H), 1.44 (td, J=8.7, 4.4Hz, 1H), 1.19 (s, 3H), 0.95 (s, 3H), 0.80 (s, 3H). 13 C NMR (150MHz, DMSO-d6) δ182.80, 169.06, 166.55, 157.95, 155.69, 150.62, 1 47.39, 142.05, 141.09, 140.80, 139.52, 138.91, 132.61, 131.74, 129.55, 12 7.94, 127.71, 125.86, 125.07, 120.44, 119.11, 118.90, 112.43, 107.82, 63. 88, 53.62, 48.09, 33.43, 27.54, 21.43, 20.62, 19.90, 12.46.HRMS: m / z[M+H] + calcd for C 39 H 33N3O4608.2544; found 608.2553.
[0051] Example 2
[0052] Compound CPA-OAc was prepared into 1×10 -5 M PBS buffer solution (pH = 7.4, DMSO / PBS = 1 / 9, 10mM), and chlorpyrifos, phoxim, trichlorfon, glufosinate, diazinon, acetamiprid, methyl parathion, dimethoate, chlorothiazide, and dichlorvos were dissolved in DMSO to prepare solutions with a concentration of 20 mg / L respectively. The fluorescence emission spectra of compound CPA-OAc in the presence of different pesticides were measured on a fluorescence spectrophotometer using fluorescence spectrometry titration method. Figure 1 The results show that the fluorescence emission intensity of CPA-OAc is the lowest in the presence of dimethoate. This shows that the compound CPA-OAc can be used as a fluorescent probe to detect dimethoate based on the enzyme inhibition principle.
[0053] Example 3
[0054] Compound CPA-OAc was prepared into 1×10 -5 M PBS buffer solution (pH = 7.4, DMSO / PBS = 1 / 9, 10mM), and dimethoate was dissolved in PBS buffer to prepare a solution with a concentration range of 0 to 25mg / L. The fluorescence emission spectrum of the compound CPA-OAc in the presence of different concentrations of dimethoate was measured on a fluorescence spectrophotometer using fluorescence spectrum titration method, as shown in FIG. Figure 2 The results showed that as the concentration of dimethoate in the solution gradually increased from 0 mg / L to 25 mg / L, the fluorescence emission intensity of the compound CPA-OAc at 501 nm gradually decreased. This shows that this compound can be used as a fluorescent probe for the sensitive detection of dimethoate.
Claims
1. A camphor-based fluorescent probe for detecting the organophosphorus pesticide dimethoate, characterized in that: Its structural formula is:
2. The method for preparing a camphor-based fluorescent probe for detecting the organophosphorus pesticide dimethoate according to claim 1, wherein The steps include: (1) Using camphor as a raw material, Claisen condensation is carried out with ethyl isonicotinate to obtain 3-(pyridine-4-formyl)-1,7,7-trimethylbicyclo[2.2.1]2-heptanone; (2) 3-(pyridine-4-formyl)-1,7,7-trimethylbicyclo[2.2.1]2-heptanone is further cyclized with 4-bromophenylhydrazine to prepare 2-(4-bromophenyl)-7,8,8-trimethyl-3-(pyridin-4-yl)-4,5,6,7-tetrahydro-2H-4,7-methanoindazole; (3) Suzuki coupling reaction of 2-(4-bromophenyl)-7,8,8-trimethyl-3-(pyridin-4-yl)-4,5,6,7-tetrahydro-2H-4,7-methanoindazole with 4-formylphenylboronic acid to prepare 4′-(7,8,8-trimethyl-3-(pyridin-4-yl)-4,5,6,7-tetrahydro-2H-4,7-methanoindazole-2-yl)-[1,1′-diphenyl]-4-carbaldehyde compound; (4) 4′-(7,8,8-trimethyl-3-(pyridin-4-yl)-4,5,6,7-tetrahydro-2H-4,7-methanoindazol-2-yl)-[1,1′-diphenyl]-4-carbaldehyde is then subjected to an aldol condensation reaction with 6-hydroxy-2H-benzofuran-3-one to obtain 6-hydroxy-2-((4′-(7,8,8-trimethyl-3-(pyridin-4-yl)-4,5,6,7-tetrahydro-2H-4,7-methanoindazol-2-yl)-[1,1′-diphenyl]-4-yl)methylene)benzofuran-3(2H)-one, namely CPA-OH; (5) CPA-OH is subjected to esterification reaction with acetyl chloride to obtain 3-oxo-2-((4′-(7,8,8-trimethyl-3-(pyridin-4-yl)-4,5,6,7-tetrahydro-2H-4,7-oxodimethanoindazol-2-yl)-[1,1′-diphenyl]-4-yl)methenyl)-2,3-dihydrobenzofuran-6-yl acetate, namely CPA-OAc.
3. A method for preparing a camphor-based fluorescent probe for detecting the organophosphorus pesticide dimethoate according to claim 2, characterized in that: The preparation steps of 3-(pyridine-4-formyl)-1,7,7-trimethylbicyclo[2.2.1]2-heptanone in step (1) are as follows: 1) Under nitrogen protection, 2.4-3 g of 60% sodium hydrogen phosphate and 50-60 mL of ethylene glycol dimethyl ether were added to a 250 mL three-necked flask equipped with a stirrer and a reflux condenser, and stirred for 20-30 min; 3.04-3.81 g of camphor was dissolved in 20-30 mL of ethylene glycol dimethyl ether and slowly added dropwise to the reaction flask using a constant pressure dropping funnel, and the mixture was reacted under reflux for 1.5-2 h; 3.02-3.78 g of ethyl isonicotinate was then dissolved in 20-30 mL of ethylene glycol dimethyl ether and slowly added dropwise to the reaction flask for 5-7 h; 2) After the reaction solution was distilled off under reduced pressure to remove ethylene glycol dimethyl ether, 100-200 mL of ethyl acetate was added to dissolve the distillation residue, which was then washed with distilled water until neutral and then with saturated brine. The organic phase was dried over anhydrous sodium sulfate and distilled to obtain 3-(pyridine-4-formyl)-1,7,7-trimethylbicyclo[2.2.1]2-heptanone.
4. A method for preparing a camphor-based fluorescent probe for detecting the organophosphorus pesticide dimethoate according to claim 2, characterized in that: The preparation steps of 2-(4-bromophenyl)-7,8,8-trimethyl-3-(pyridin-4-yl)-4,5,6,7-tetrahydro-2H-4,7-methanoindazole in step (2) are as follows: 1) To a 100 mL single-necked flask equipped with a stirrer and a reflux condenser, add 2.57-2.83 g of 3-(pyridine-4-carbonyl)-1,7,7-trimethylbicyclo[2.2.1]2-heptanone, 40-60 mL of ethanol, and 3.74-3.93 g of 4-bromophenylhydrazine. Then, add 3-5 drops of acetic acid and stir under reflux at 80°C for 24 h. 2) The reaction solution was filtered and washed thoroughly with ethanol, and the resulting solid was dried under vacuum at 45°C for 24 to 36 hours to obtain 2-(4-bromophenyl)-7,8,8-trimethyl-3-(pyridin-4-yl)-4,5,6,7-tetrahydro-2H-4,7-methanoindazole.
5. A method for preparing a camphor-based fluorescent probe for detecting the organophosphorus pesticide dimethoate according to claim 2, characterized in that: The preparation steps of 4′-(7,8,8-trimethyl-3-(pyridin-4-yl)-4,5,6,7-tetrahydro-2H-4,7-endomethylindazol-2-yl)-[1,1′-diphenyl]-4-carbaldehyde in step (3) are as follows: 1) Under nitrogen protection, to a 100 mL three-necked flask equipped with a stirrer and a reflux condenser, 2.04-2.45 g of 2-(4-bromophenyl)-7,8,8-trimethyl-3-(pyridin-4-yl)-4,5,6,7-tetrahydro-2H-4,7-methanoindazole, 1.5-1.8 g of 4-formylphenylboronic acid, 0.06-0.07 g of Pd(PPh3)4, and 5-6 mL of a 1 M K2CO3 aqueous solution were added, followed by the addition of 50-60 mL of a 5 / 1 by volume 1,4-dioxane / water mixed solvent. The reaction was refluxed for 24-36 h and monitored by TLC. 2) The reaction solution was cooled to room temperature, filtered to remove the catalyst, and then the solvent was distilled off. 30-40 mL of ethyl acetate was added to dissolve the distillation residue. The organic phase was washed with saturated brine until neutral. The solvent was evaporated to obtain a crude product. The crude product was purified by silica gel column chromatography with petroleum ether / ethyl acetate = 5 / 1 to obtain 4′-(7,8,8-trimethyl-3-(pyridin-4-yl)-4,5,6,7-tetrahydro-2H-4,7-endomethylindazol-2-yl)-[1,1′-diphenyl]-4-carbaldehyde.
6. A method for preparing a camphor-based fluorescent probe for detecting the organophosphorus pesticide dimethoate according to claim 2, characterized in that: The preparation steps of CPA-OH in step (4) are as follows: 1) Add 0.50-0.54 g of 4′-(7,8,8- trimethyl-3-(pyridin-4-yl)-4,5,6,7-tetrahydro-2H-4,7-methanoindazol-2-yl)-[1,1′-diphenyl]-4- Formaldehyde, 0.17-0.19 g 6-hydroxy-2H-benzofuran-3-one, 15-20 mL ethanol and 0.092-0.1 g sodium hydroxide, react at 60-70°C for 1-2 hours; 2) After the reaction solution was distilled to remove ethanol, the resulting crude product was purified by silica gel column chromatography using petroleum ether / ethyl acetate = 3 / 1 to obtain compound CPA-OH.
7. A method for preparing a camphor-based fluorescent probe for detecting the organophosphorus pesticide dimethoate according to claim 2, characterized in that: The preparation steps of CPA-OAc in step (5) are as follows: 1) Under nitrogen, dissolve 0.28-0.34 g CPA-OH and 0.33-0.39 g cesium carbonate in 15-20 mL anhydrous acetonitrile and stir for 30-40 min. 2) Slowly add 0.16-0.20 g of acetyl chloride dropwise in an ice bath, react for 1.5-2 h, then raise the temperature to reflux and continue the reaction for 2-3 h; 3) The reaction solution was distilled to remove acetonitrile, and 15-20 mL of dichloromethane was added to dissolve the distillation residue, which was washed with saturated brine until neutral. After drying and distillation, the resulting crude product was further purified by silica gel column chromatography with petroleum ether / ethyl acetate = 1 / 1 to obtain CPA-OAc.
8. Use of the fluorescent probe according to claim 1 in detecting dimethoate, wherein the purpose of the use is not to diagnose or treat a disease.
9. The use according to claim 8, characterized in that The fluorescent probe can undergo an enzymatic hydrolysis reaction with carboxylesterase. Under irradiation with ultraviolet light of a wavelength of 375nm, the fluorescent color of the solution changes from colorless to green. Since dimethoate can effectively inhibit the activity of carboxylesterase, under irradiation with a 375nm ultraviolet lamp, the fluorescent color of the compound solution changes from green to colorless.
10. The use according to claim 8, characterized in that The fluorescent probe can specifically identify dimethoate and can sensitively detect the content of dimethoate in a solution, with a detection concentration range of 0 to 25 mg / L and a detection limit as low as 110.4 μg / L.