A water-soluble fluorescent naphthalene ring [3] aromatic hydrocarbon and its preparation method and application

Abstract

The present invention discloses a method for preparing a water-soluble fluorescent naphthyl[3]arene and its application. The method comprises the following steps: demethylating the naphthyl[3]arene with boron tribromide to obtain a fully hydroxy-substituted naphthyl[3]arene (compound 2); subsequently reacting the compound with tert-butyl bromoalkyl acid to obtain a fully ester-substituted naphthyl[3]arene (compound 3); subsequently hydrolyzing compound 3 with trifluoroacetic acid to obtain a fully carboxylic acid-substituted naphthyl[3]arene; and finally, dissolving the fully sodium carboxylate-substituted naphthyl[3]arene by adjusting the pH. The method prepares a fully sodium carboxylate-substituted naphthyl[3]arene and its application in detecting paraquat. As a supramolecular macrocyclic aromatic hydrocarbon fluorescent probe, the compound has the advantages of simple synthesis, low cost, good selectivity, high sensitivity, and can be used for rapid detection of paraquat and its derivatives in water.

Description

Technical Field

[0001] The present invention belongs to the technical field of organic synthesis and analysis and detection, and relates to the preparation and application of water-soluble sodium carboxylate-naphthyl[3]arene. Background Art

[0002] Paraquat (PQ), chemically known as 1,1'-dimethyl-4,4-dipyridinium cation salt, is a non-selective, fast-acting herbicide and a common pesticide residue. Due to its high toxicity, it is easily absorbed through the digestive tract, respiratory tract, and skin, causing organ damage and even death, posing a serious risk to human health and the environment. Therefore, there is an urgent need to develop methods for rapid and convenient detection of paraquat residues.

[0003] Traditional methods for pesticide residue detection include high-performance liquid chromatography, gas chromatography, liquid chromatography-mass spectrometry, gas chromatography-mass spectrometry, and capillary electrophoresis. These methods primarily rely on large-scale laboratory instruments, offering high accuracy and reliability. However, these instruments require complex sample pretreatment and are unable to achieve real-time and rapid detection.

[0004] New methods for detecting paraquat and its derivatives are still being developed. For example, Professor Xiao Xin of the Institute of Applied Chemistry of Guizhou University published a paper titled "Utilizing symmetrical tetramethyl cucurbit[6]uril-based supramolecular fluorescence probe for detection of paraquat in water" (Spectrochimica Acta Part A:Molecular and Biomolecular Spectroscopy, 2024, 310:123845). This study constructed a supramolecular complex to achieve sensitive detection of paraquat and its derivatives. Professor Chen Juntai of Yangming Chiao Tung University in Taiwan published a paper titled "Pyranine-Grafted Nanoporous Membranes for Sensing Paraquat Derivatives" (ACS Appl. Nano Mater., 2023, 6(8):6831-6840). This paper constructed a pyranine-modified anodized aluminum oxide (AAP) porous membrane to achieve the detection of paraquat and its derivatives. Although these detection results are relatively accurate, there are still problems such as high detection cost and poor detection selectivity. Summary of the Invention

[0005] To address the deficiencies of the prior art, the present invention provides a sodium carboxylate-naphthyl[3]arene compound, a method for preparing the compound, and the use of the compound in detecting paraquat. As a supramolecular macrocyclic aromatic hydrocarbon fluorescent probe, the compound has the advantages of simple synthesis, low cost, good selectivity, and high sensitivity, and can be used to rapidly detect paraquat and its derivatives in water.

[0006] The purpose of the present invention is achieved through the following technical solutions:

[0007] A method for preparing carboxylic acid-naphthyl[3]arene.

[0008]

[0009] Wherein, R=-CH2(CH2)nCOONa n=0~2

[0010] The above-mentioned method for preparing sodium carboxylate-naphthyl[3]arene comprises the following steps:

[0011] (1) The synthesis method of compound H1 can be prepared according to patent (CN202111194619.7). The preparation method is as follows:

[0012] a. Compound 1 and trifluoromethanesulfonic anhydride were stirred at 0°C under alkaline conditions to obtain compound 2;

[0013] b. Compound 2 and 2,5-dimethoxyphenylboronic acid were dissolved in a mixed solvent of toluene, ethanol, and distilled water. Under a nitrogen atmosphere, the mixture was stirred and a catalyst was added. The mixture was heated under reflux to obtain compound 3 via Suzuki coupling. c. Fluorescent naphthyl ring [3] aromatic hydrocarbon monomer was dissolved in a solvent, a catalyst was added, and the mixture was stirred. H1 was obtained via a condensation reaction of the monomer with dimethoxymethane.

[0014] (2) Compound H1 is dissolved in an organic solvent under inert conditions, and then 16-32 times the molar amount of boron tribromide is added and stirred at 0-35°C for 5-12 hours. After the reaction is complete, ice water is added for precipitation, and the crude product of Compound H2 is obtained by filtration. The crude product is then washed with dichloromethane and water, and dried in vacuo to obtain Compound 2.

[0015] (3) Under inert gas protection, compound H2 and 20-fold molar amount of base are added to a high-boiling point organic solvent. After stirring at 60-110°C for 30 minutes, 20-fold molar amount of tert-butyl bromoalkyl is added and stirred for 2-12 hours. After the reaction is completed, extraction is performed with dichloromethane and water. The organic phase is collected, dried over anhydrous magnesium sulfate, filtered, and the solvent is removed by rotary evaporation. Compound H3 is obtained by column chromatography.

[0016] (4) Compound H3 was dissolved in an organic solvent, trifluoroacetic acid was added and stirred at 0-35°C for 1-5 hours. After the reaction was completed, the mixture was filtered, washed with dichloromethane several times, and dried in vacuo to obtain compound H4.

[0017] (5) Compound H4 was dissolved in a sodium hydroxide solution with a pH of 8 to 8.5, and the pH was adjusted to 8.5 to 9.5 using a 1 M sodium hydroxide standard solution to obtain a sodium carboxylate-naphthyl[3]arene solution.

[0018] Preferably, in the above method, the organic solvent in step (1) includes dichloromethane, chloroform, and toluene.

[0019] Preferably, in the above method, in step (2), the organic solvent includes dichloromethane, chloroform or toluene; and the amount of BBr3 added is 16 to 32 times the molar amount of compound H1.

[0020] Preferably, in the above method, the base in step (3) includes Na2CO3, K2CO3, KOH or NaOH, and the amount of the base added is 15 to 25 times the molar amount of compound 2.

[0021] Preferably, in the above method, the high boiling point solvent in step (3) includes toluene, 1,4-dioxane, acetonitrile, N,N-dimethylformamide, N,N-dimethylacetamide and N-methylpyrrolidone.

[0022] Preferably, in the above method, in step (3), the amount of tert-butyl bromide added is 15 to 25 times the molar amount of compound H2.

[0023] Preferably, in the above method, in step (4), the organic solvent includes dichloromethane, chloroform or ethyl acetate.

[0024] Preferably, the inert gas in the above steps includes nitrogen and argon.

[0025] The reaction scheme of the present invention is:

[0026]

[0027] Compared with the prior art, the present invention has the following advantages:

[0028] (1) The sodium carboxylate-naphthyl[3]arene provided by the present invention is simple to synthesize and can achieve rapid, sensitive and economical detection of paraquat and its derivatives in water.

[0029] (2) The sodium carboxylate-naphthyl[3]arene provided by the present invention is a compound that can emit fluorescence under the excitation of a light source of a specific wavelength and can selectively bind to paraquat to quench the fluorescence of compound 4. This detection method has strong anti-interference ability against other organic small molecules and metal ions and can achieve specific detection and identification of paraquat. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is the UV-visible absorption spectrum and fluorescence emission spectrum of the sodium carboxylate-naphthyl[3]arene solution configured in Example 2.

[0031] Figure 2 The fluorescence emission spectra (a) and fluorescence intensity variation trend diagram (b) of the sodium carboxylate-naphthyl[3]arene solution configured in Example 2 and paraquat derivatives with different equivalent ratios are shown.

[0032] Figure 3 This is the fluorescence response diagram of the sodium carboxylate-naphthyl[3]arene solution configured in Example 2 and different water-soluble pollutants. DETAILED DESCRIPTION

[0033] The specific examples of the present invention are further described below with reference to the accompanying drawings and specific embodiments, but the scope of protection claimed by the present invention is not limited to the scope described in the embodiments.

[0034] Example 1

[0035] This embodiment provides a method for preparing carboxylic acid-naphthyl[3]arene, comprising the following steps:

[0036] Synthesis of acetic acid-naphthyl[3]arene (R is acetic acid, n=0); the synthetic route is as follows:

[0037]

[0038] The synthesis steps are as follows:

[0039] (1) Synthesis of compound H2:

[0040]

[0041] Compound H1 (494.4 mg, 0.5 mmol) was weighed and added to a 100 mL two-necked round-bottom flask under nitrogen. 50 mL of chloroform was added to the reaction flask, followed by BBr (1 ml, 10 mmol). The mixture was stirred at room temperature for 12 h. After the reaction, an appropriate amount of ice water was added for precipitation. The precipitate was then rapidly filtered, washed several times with dichloromethane and water, and dried under vacuum to yield a brown solid (Compound H2, 406 mg).

[0042] H NMR spectrum data of compound H2:1 H NMR (400MHz, DMSO-d6): δ8.85(s,1H),8.78(s,1H),8.01(d,J=1.8Hz,1H),7.93(d, J=8.5Hz,1H),7.63(dd,J=8.4,1.7Hz,1H),6.88(s,1H),6.70(s,1H),3.79(s,1H).

[0043] Synthesis of compound H3-1

[0044]

[0045] Compound H2 (100 mg, 0.1 mmol) and anhydrous potassium carbonate (276 mg, 2 mmol) were weighed and added to a 100 mL flask under nitrogen. The mixture was heated to 80°C and stirred for 0.5 h before the addition of tert-butyl bromoacetate (390 mg, 2 mmol). The mixture was stirred for 2 h. After the reaction, the mixture was extracted with dichloromethane and water. The organic phase was collected, dried over anhydrous magnesium sulfate, and the solvent was removed by rotary evaporation. Column chromatography afforded a brown solid (Compound H3-1, 207 mg) in an 85% yield.

[0046] H NMR spectrum data of compound H3-1: 1 H NMR (400MHz, Chloroform-d): δ7.90-7.84(m,1H),7.76(dd,J=8.6,1.5Hz,1H),7.38( s,0H),6.79(s,1H),4.58(s,1H),4.52(s,1H),4.16(s,1H),1.51(s,5H),1.40(s,5H).

[0047] Synthesis of compound 4:

[0048]

[0049] Compound H3-1 (48.6 mg, 0.02 mmol) was weighed and placed in a 25 mL flask. 5 mL of dichloromethane and 5 mL of trifluoroacetic acid were added and stirred at 0°C. The reaction progress was monitored by TLC, and completion occurred after 5 h. The precipitate was collected by filtration, washed repeatedly with dichloromethane, and dried under vacuum to afford H4-1 as a light brown solid in a 90% yield.

[0050] H NMR spectrum data of compound H4-1: 1H NMR (400MHz, Methanol-d4) δ7.88(d,J=8.6Hz,1H),7.73(dd,J=8.4,1.7Hz,1H),7.28(s,1H),6.94(s,1H),4.74(s,2H),4.61(s,2H),4.17(s,1H).

[0051] Example 2

[0052] This embodiment provides a method for preparing carboxylic acid-naphthyl[3]arene, comprising the following steps:

[0053] Synthesis of propionic acid-naphthyl[3]arene (R is ethylpropionic acid group, n=1); the synthetic route is as follows:

[0054]

[0055] The synthesis steps are as follows:

[0056] Synthesis of compound H3-1

[0057]

[0058] Compound H2 (100 mg, 0.1 mmol) and anhydrous potassium carbonate (276 mg, 2 mmol) were weighed and added to 50 mL of DMF in a 100 mL flask under nitrogen. The mixture was heated to 110°C and stirred for 0.5 h before the addition of tert-butyl 3-bromopropionate (418 mg, 2 mmol) and stirring for 8 h. After completion of the reaction, the mixture was extracted with dichloromethane / water, and the organic phase was collected, dried over anhydrous magnesium sulfate, and the solvent was removed by rotary evaporation. Column chromatography afforded a brown solid (Compound H3-2, 223 mg) in an 86% yield.

[0059] Synthesis of compound 4:

[0060]

[0061] Compound H3-2 (52.1 mg, 0.02 mmol) was weighed and placed in a 25 mL flask. 5 mL of chloroform and 5 mL of trifluoroacetic acid were added and stirred at 25°C. The reaction progress was monitored by TLC, and the reaction was complete after 2 h. The precipitate was collected by filtration, washed repeatedly with dichloromethane, and dried under vacuum to obtain a light brown solid H4-2 in a 90% yield.

[0062] Example 3

[0063] This embodiment provides a method for preparing carboxylic acid-naphthyl[3]arene, comprising the following steps:

[0064] The synthesis of butyric acid-naphthyl[3]arene (R is butyric acid group, n=2); the synthesis route is as follows:

[0065]

[0066] The synthesis steps are as follows:

[0067] Synthesis of compound H3-1

[0068]

[0069] Compound H2 (100 mg, 0.1 mmol) and Na2CO3 (212 mg, 2 mmol) were weighed and added to 50 mL of N,N-dimethylacetamide in a 100 mL flask under nitrogen. The mixture was heated to 110°C and stirred for 0.5 h before the addition of tert-butyl 4-butyrate (446 mg, 2 mmol) and stirring for 12 h. After completion of the reaction, the mixture was extracted with dichloromethane and water, and the organic phase was collected, dried over anhydrous magnesium sulfate, and the solvent was removed by rotary evaporation. Column chromatography afforded a brown solid (Compound H3-3, 211 mg) in a 78% yield.

[0070] Synthesis of compound 4:

[0071]

[0072] Compound H3-2 (52.1 mg, 0.02 mmol) was weighed and placed in a 25 mL flask. 5 mL of chloroform and 5 mL of trifluoroacetic acid were added and stirred at 35°C. The reaction progress was monitored by TLC, and the reaction was complete after 5 h. The precipitate was collected by filtration, washed repeatedly with dichloromethane, and dried under vacuum to obtain a light brown solid H4-2 in a 90% yield.

[0073] Example 4

[0074] Preparation of water-soluble sodium carboxylate-naphthyl[3]arene solution and ultraviolet fluorescence spectrum test

[0075] The carboxylic acid-naphthyl[3]arene (H4-1) prepared in Example 1 was prepared with an aqueous solution of pH=8 to a concentration of 1×10 - 6 mol / L solution, and adjusted the pH to 8.5-9.5 with standard 1M sodium hydroxide solution. UV-visible absorption spectrum test and fluorescence emission spectrum test were carried out, and the normalized superposition spectrum of the measured UV-visible absorption spectrum and fluorescence emission spectrum was shown as follows: Figure 1 As shown, its UV-visible absorption wavelength is 320 nm, and the strongest emission wavelength of the fluorescence emission spectrum is 446 nm.

[0076] Example 5

[0077] Fluorometric Titration of Water-Soluble Sodium Carboxylate-Naphthyl[3]arene

[0078] Preparation of sodium carboxylate-naphthyl[3]arene 5×10 -7 mol / L solution (preparation method as in Example 4), and then gradually add 0 to 2 times the equivalent of paraquat solution, and perform emission spectrum test at an excitation wavelength of 320nm. Figure 2 It can be found that as the paraquat concentration in the test system increases, the fluorescence emission intensity gradually decreases. This shows that the fluorescent probe P has reliable sensitivity for identifying paraquat, and its detection limit is 1.83*10^-8M according to the 3σ method.

[0079] Example 6

[0080] Prepare 5×10 -7 mol / L solution (preparation method as in Example 4), add 4eq of aluminum ions (Al 3+ ), iron ions (Fe 3+ ), cesium ions (Cs 2+ ), manganese ions (Mn 2+ ), mercury ions (Hg + ), copper ions (Cu 2+ ), Rhodamine B, Paraquat. The fluorescence emission spectrum was tested at 320 nm. Figure 3 It can be seen that, except for paraquat, the fluorescence emission intensity of the system changes little. After adding paraquat, the fluorescence intensity is significantly quenched, and the quenching degree (1-F / F0) reaches 94.6%.

[0081] It should be understood that the above detailed description of the technical solutions of the present invention with the help of optimized embodiments is illustrative rather than restrictive, and it cannot be determined that the specific implementation methods of the present invention are limited to these. For ordinary technicians in the technical field to which the present invention belongs, without departing from the concept of the present invention, modifications to the technical solutions recorded in each embodiment, or equivalent replacement of some of the technical features therein, should be deemed to fall within the scope of patent protection determined by the claims submitted by the present invention.

[0082] The above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention and are not intended to limit the embodiments of the present invention. Those skilled in the art will appreciate that other variations or modifications may be made based on the above description. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention are intended to be included within the scope of protection of the claims of the present invention.

Claims

1. A water-soluble fluorescent naphthyl[3]arene, characterized in that: Its structural formula is: Wherein, R=-CH2(CH2)nCOONa n=0~2.

2. The method for preparing a water-soluble fluorescent naphthyl[3]arene according to claim 1, characterized in that: The following steps are involved: (1) The synthesis method of compound H1 is as follows: a. Compound 1 and trifluoromethanesulfonic anhydride were stirred at 0°C under alkaline conditions to obtain compound 2; b. Compound 2 and 2,5-dimethoxyphenylboronic acid were dissolved in a mixed solvent of toluene, ethanol, and distilled water, stirred under a nitrogen atmosphere, and a catalyst was added. The mixture was heated under reflux to obtain compound 3 by Suzuki coupling. c. The fluorescent compound 3 is dissolved in a solvent, a catalyst of boron trifluoride ether is added, and the mixture is stirred to obtain H1 by condensation reaction of the monomer with dimethoxymethane; (2) Under inert gas protection, H1 is dissolved in an organic solvent, BBr3 is added, and the mixture is stirred at 0-35°C for 5-12 hours. After the reaction is completed, ice water is added to precipitate the solid, which is filtered, washed with dichloromethane / water several times, and dried in vacuo to obtain compound H2; (3) Under the protection of inert gas, compound H2 and a base are added to a high-boiling point organic solvent, reacted at 60-80°C for 10-30 minutes, then tert-butyl bromide is added and stirred for 2-12 hours, extracted with dichloromethane and dried over anhydrous Na2SO4, and the solvent is removed by rotary evaporation. Compound H3 is obtained by column chromatography, wherein the high-boiling point organic reagent is selected from toluene, 1,4-dioxane, acetonitrile, N,N-dimethylformamide, N,N-dimethylacetamide or N-methylpyrrolidone; (4) Compound H3 is dissolved in an organic solvent, trifluoroacetic acid is added at 0-35°C and stirred for 1-5 hours. After the reaction is completed, the mixture is filtered, washed with dichloromethane and water for multiple times, and dried in vacuo to obtain compound H4; compound H4 is dissolved in a sodium hydroxide solution with a pH of 8-8.5, and the pH is adjusted to 8.5-9.5 with a 1M sodium hydroxide standard solution to obtain a water-soluble fluorescent naphthyl ring [3] aromatic hydrocarbon solution.

3. The method for preparing water-soluble fluorescent naphthyl ring [3] aromatic hydrocarbons according to claim 2, characterized in that: In step (2), the organic solvent is selected from dichloromethane, chloroform or toluene; the amount of BBr3 added is 16 to 32 times the molar amount of compound H1.

4. The method for preparing water-soluble fluorescent naphthyl ring [3] aromatic hydrocarbons according to claim 2, characterized in that: In step (3), the base is selected from NaOH or KOH; the amount of the base added is 15 to 25 times the molar amount of compound H2.

5. The method for preparing water-soluble fluorescent naphthyl ring [3] aromatic hydrocarbons according to claim 4, characterized in that: The base is replaced by Na2CO3 or K2CO3.

6. The method for preparing water-soluble fluorescent naphthyl[3]arene according to claim 2, characterized in that: In step (3), the amount of tert-butyl bromide added is 15 to 25 times the molar amount of compound H2.

7. The method for preparing water-soluble fluorescent naphthyl[3]arene according to claim 2, characterized in that: In step (4), the organic solvent is selected from dichloromethane, chloroform or ethyl acetate.

8. The method for preparing water-soluble fluorescent naphthyl[3]arene according to claim 2, characterized in that: The inert gas is argon or nitrogen.

9. Use of the water-soluble fluorescent naphthyl[3]arene according to claim 1 in the preparation of a reagent for rapid detection of paraquat in water.

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