A quinoxalinone compound containing styrylpyridine and a preparation method thereof

Abstract

The present invention discloses a quinoxalinone containing styrylpyridine and its preparation method, belonging to the field of chemical analysis and detection. This compound is first obtained by condensing 2-amino-4-nitrodiphenyl with pyruvic acid to get phenylquinoxalinone, and then condensing with pyridylbenzaldehyde to obtain the final product. The reaction conditions are mild and the steps are simple to operate. At the same time, this compound has good fluorescence emission performance and reaction activity, and can be used as a fluorescent probe to achieve rapid and sensitive detection of the nerve agent simulant diethyl chlorophosphate DCP.

Description

Technical Field

[0001] The present invention relates to a quinoxalinone compound containing styrylpyridine and a preparation method thereof, belonging to the field of chemical analysis and detection. Background Art

[0002] In the past few decades, chemical agents have been frequently used in terrorist attacks and regional wars, bringing great harm to humans, making the development of their detection technologies always a research hotspot. Sarin is a typical nerve agent that destroys the human nervous system by interfering with acetylcholinesterase in the human body, thereby causing human poisoning and death. As a highly toxic and volatile chemical agent, sarin poses a great threat to human life and health and social security. Therefore, it is very important to develop a method for efficiently and rapidly detecting nerve agents. Due to the high toxicity and difficulty in obtaining sarin, diethyl chlorophosphate (hereinafter referred to as DCP) is usually used as its mimic for test evaluation in laboratories. In traditional nerve agent detection methods, there are problems such as cumbersome operation, long response time, and low sensitivity in surface acoustic wave method, Raman spectroscopy, chromatography, electrochemistry method, etc., which seriously limit their application scenarios.

[0003] Due to its advantages such as high sensitivity, fast response speed, low cost, and simple operation, the fluorescence dye detection method has been widely used in fields such as analytical sensing in recent years. Fluorescent dyes containing pyridine groups have high reactivity and exhibit excellent sensing properties such as high sensitivity and fast response time to the nerve agent simulant DCP (J. Yao, Y. Fu, W. Xu, et al. Anal. Chem., 2016, 88, 2497 - 2501; C. Sun, W. Xiong, W. Ye, et al. Anal. Chem., 2018, 7131 - 7134; X. Li, Y. Lv, S. Chang, et al. Anal. Chem., 2019, 91, 10927 - 10931; W. Meng, Z. Pei, Y. Wang, et al. Journal of Hazardous Materials., 2021, 410, 124811; P. Zheng, Z. Cui, H. Liu, et al. Journal of Hazardous Materials., 2021, 415, 125619). In addition, quinoxalinone derivatives have good fluorescence properties and drug activities and are widely used in the fields of biological and chemical detection. They are a potential fluorescent probe molecular framework, and the styrylpyridine structure has certain aggregation-induced emission characteristics, which can reduce the fluorescence quenching effect caused by aggregation in the fluorescent molecule solution, thereby improving the probe sensing detection performance (L. Shi, Q. Guan, X. Gao, et al. Anal. Chem., 2018, 90, 9218 - 9225). Therefore, in order to solve the problems existing in traditional nerve agent detection methods, such as cumbersome operation, long response time, and low sensitivity, it is of great significance to design a new type of fluorescent dye containing styrylpyridine quinoxalinone group that can detect nerve agents simply, quickly, and sensitively. Summary of the Invention

[0004] The object of the present invention is to solve the problems existing in traditional nerve agent detection methods, such as cumbersome operation, long response time, and low sensitivity. To this end, a quinoxalinone compound containing styrylpyridine and its preparation method are provided. This type of compound can achieve simple, rapid, and sensitive detection of the nerve agent simulant DCP.

[0005] The technical solution adopted by the present invention to solve the above problems is that the structural formula of the quinoxalinone compound containing styrylpyridine is as follows:

[0006]

[0007] The preparation reaction formula of the quinoxalinone compound containing styrylpyridine of the present invention is as follows:

[0008]

[0009] The preparation method of the quinoxalinone compound containing styrylpyridine of the present invention is as follows:

[0010] Step 1: Add 2 mmol of 2-amino-4-nitrodiphenylamine (III) into 15 - 20 mL of ethanol, stir for 5 - 10 min, then add 0.8 - 1.0 mL of pyruvic acid, reflux and react for 3 - 6 h under nitrogen protection. After the reaction is completed, cool the product mixture to 18 - 25 °C and then perform suction filtration. Wash the filter cake with 50 mL of deionized water each time for 3 - 5 times, and dry to obtain a yellow solid product 1-phenyl-3-methyl-2(1H)-quinoxalinone (II). The product is further purified by recrystallization with absolute ethanol;

[0011] Step 2: Under nitrogen protection, add 1 - 1.2 mmol of 4-(4-pyridyl)benzaldehyde (II) into 5 - 10 mL of anhydrous tetrahydrofuran, stir at 25 - 30 °C for 5 - 10 min, then dropwise add 1 mL of boron trifluoride diethyl ether solution with a mass fraction of 40 - 50% to form a mixed solution. After the mixed solution is stirred for 20 - 30 min, add 1 mmol of 1-phenyl-3-methyl-2(1H)-quinoxalinone (II), and end the reflux reaction after 4 - 6 h;

[0012] Step 3: Add 150 mL of deionized water to the reaction mixture, adjust the pH of the solution to 7 - 8 with saturated sodium bicarbonate aqueous solution, then extract with 50 mL of ethyl acetate each time for 3 times, combine the organic phases, rotary evaporate and concentrate to obtain a solid crude product, and finally obtain the quinoxalinone compound (I) containing styrylpyridine through column chromatography separation and purification.

[0013] In the said Step 3, the eluent used for column chromatography separation is dichloromethane / ethyl acetate, and the volume ratio is 4 - 6∶1.

[0014] The beneficial effects of the present invention: Based on the good reaction catalytic activity of the pyridine group, a quinoxalinone compound containing styrylpyridine is designed. The reaction process has mild conditions and simple steps. At the same time, this compound can be used as a fluorescence probe to achieve simple, rapid and sensitive detection of the nerve agent simulant DCP, and has potential applications in the fields of biomedicine and chemical detection. Brief Description of the Drawings

[0015] Figure 1 Fluorescence emission curve spectrum of compound (I) in different tetrahydrofuran / water ratio systems

[0016] In the figure: Curves a - i respectively represent the fluorescence emission curves of the water content of 0, 10%, 30%, 50%, 70%, 80%, 90%, 95%, 99% in the tetrahydrofuran / water system;

[0017] The abscissa is the fluorescence emission wavelength, with the unit of nm; the ordinate is the fluorescence intensity.

[0018] Figure 2 Fluorescence titration spectrum of compound (I) against DCP

[0019] In the figure: Curves a - i respectively represent the fluorescence emission curves when the DCP concentration is 0, 1.0×10 -5 mol / L, 1.5×10 -5 mol / L, 2.0×10 - 5 mol / L, 2.5×10 -5 mol / L, 3.0×10 -5 mol / L, 3.5×10 -5 mol / L, 4.0×10 -5 mol / L, 4.5×10 -5 mol / L, 5.0×10 -5 mol / L, 5.5×10 -5 mol / L, 6.0×10 -5 mol / L;

[0020] The abscissa is the fluorescence emission wavelength, with the unit of nm; the ordinate is the fluorescence intensity.

[0021] Figure 3 Fluorescence linear fitting graph of compound (I) against DCP concentration

[0022] In the figure: The abscissa is the concentration of DCP, with the unit of 10 -5 mol / L; the ordinate is the fluorescence intensity.

[0023] Figure 4 Fluorescence emission spectrum of compound (I) against different phosphorus - containing compounds

[0024] In the figure: The phosphorus - containing compounds are respectively DCP (diethyl chlorophosphate), DMMP (dimethyl methylphosphonate), DCNP (diethyl cyanophosphonate), DMNP (methyl paraoxon), TEP (triethyl phosphate) and TPP (triphenyl phosphate);

[0025] The abscissa is the fluorescence emission wavelength, with the unit of nm; the ordinate is the fluorescence intensity. Specific implementation manners

[0026] The present invention will be further described below in conjunction with the embodiments and the drawings.

[0027] Example 1

[0028] Synthesis of Compound (I)

[0029] Step 1: Add 2 mmol of 2-amino-4-nitrodiphenylamine (III) to 20 mL of ethanol. After stirring for 5 min, add 1.0 mL of pyruvic acid. React under reflux for 6 h under nitrogen protection. After the reaction is completed, cool the product mixture to 20 °C and then perform suction filtration. Wash the filter cake 5 times with deionized water, and dry to obtain a yellow solid product 1-phenyl-3-methyl-2(1H)-quinoxalinone (II), which is then purified by recrystallization with absolute ethanol;

[0030] Step 2: Under nitrogen protection, add 1.2 mmol of 4-(4-pyridyl)benzaldehyde (II) to 8 mL of anhydrous tetrahydrofuran. Stir at 25 °C for 5 min, and then slowly add 1 mL of boron trifluoride etherate with a mass fraction of 48% to form a mixed solution. After the mixed solution is stirred for 30 min, add 1 mmol of 1-phenyl-3-methyl-2(1H)-quinoxalinone (II), and end the reaction after refluxing for 4 h;

[0031] Step 3: Add 150 mL of deionized water to the reaction mixture. Adjust the pH of the solution to 7 with saturated sodium bicarbonate aqueous solution, then extract 3 times with 50 mL of ethyl acetate. Combine the organic phases, concentrate by rotary evaporation to obtain a solid crude product, and finally separate and purify to obtain the styrylpyridine-containing quinoxalinone compound (I) by column chromatography. The eluent is dichloromethane / ethyl acetate with a volume ratio of 4:1.

[0032] NMR and mass spectrometry analysis and characterization of Compound (I):

[0033] 1 H NMR (600 MHz, DMSO-d6), δ: 8.59 (d, J = 5.5 Hz, 2H), 8.09 (d, J = 16.2 Hz, 1H), 7.83 (s, 4H), 7.71 (d, J = 5.9 Hz, 2H), 7.67 (s, 1H), 7.65 - 7.49 (m, 4H), 7.44 - 7.26 (m, 4H), 6.49 (d, J = 8.2 Hz, 1H); 1313C NMR (151 MHz, DMSO-d6), δ: 153.59, 151.84, 149.78, 149.68, 145.65, 137.25, 136.30, 136.02, 135.55, 133.44, 132.07, 129.61, 129.48, 128.77, 128.67, 128.58, 128.01, 127.22, 126.92, 125.60, 123.34, 122.47, 120.52, 120.35, 114.68; ESI-MS: found, m / z 402.1600 (M+H + ), calculated for [C 27 H 19 N3O+H + : 402.1601.

[0034] Example 2

[0035] Fluorescence emission performance of compound (I) in the tetrahydrofuran / water system

[0036] As Figure 1 , when the water content in the tetrahydrofuran / water system is greater than 70%, the fluorescence intensity of compound (I) decreases significantly. However, when the water content is 90 - 99%, compound (I) still maintains a certain fluorescence intensity, indicating that compound (I) has good fluorescence emission performance.

[0037] Example 3

[0038] Fluorescence titration experiment of compound (I) with DCP

[0039] Prepare a methanol solution of compound (I) with a concentration of 1.0×10 -5 mol / L, and then sequentially add a methanol solution of DCP with a concentration of 0 - 6.0×10 -5 mol / L to 2 mL of the compound (I) solution, and measure its fluorescence emission spectrum (excitation wavelength: 360 nm). As Figure 2 , after adding the DCP solution, a significant enhancement of fluorescence emission appears near 512 nm for compound (I), and as the concentration of the DCP solution increases, the fluorescence intensity gradually increases. Moreover, under the irradiation of a 365 nm ultraviolet lamp, the solution rapidly changes from a light cyan fluorescence to a yellow fluorescence, which should be the fluorescence emission phenomenon of protonation after the reaction of compound (I) with DCP. As Figure 3 , the concentrations of compound (I) and DCP are in the range of 1.0 - 3.5×10 -5 mol / L and 4.0×10 -5 - 6.0×10 -5It showed a linear relationship within the range of -9 mol / L. By calculation, the lowest detection limit of compound (I) for DCP was 6.38×10

[0040] Example 4

[0041] Selectivity experiment of compound (I) for DCP

[0042] Prepare a methanol solution of compound (I) with a concentration of 1.0×10 -5 mol / L. Take 2 mL of the compound (I) solution and add it to 7 sample bottles, numbered 1 - 7. Among them, sample bottle No. 1 is used as a blank control. Then prepare methanol solutions of 1.0×10 -2 mol / L of DCP (diethyl chlorophosphate), DCNP (diethyl cyanophosphonate), DMNP (methyl paraoxon), DMMP (dimethyl methylphosphonate), TEP (triethyl phosphate), and TPP (triphenyl phosphate). Then take 20 μL of the methanol solutions of DCP, DCNP, DMNP, DMMP, TEP, and TPP and add them to sample bottles No. 2 - 7 in sequence. Then measure their fluorescence emission spectra. As Figure 4 shown, only after adding DCP to sample bottle No. 2, the fluorescence intensity increased significantly, and there was no obvious fluorescence enhancement in other sample bottles, indicating that compound (I) has good selectivity for DCP.

Claims

1. A quinoxalinone compound containing styrylpyridine, characterized in that: The structural formula of the quinoxalinone containing styrylpyridine is as follows:

2. A method for preparing a quinoxalinone compound containing styrylpyridine as described in claim 1, characterized in that, The preparation method comprises the following steps: Step 1: Add 2 mmol of 2-amino-4-nitrodiphenylamine to 15 - 20 mL of ethanol, stir for 5 - 10 min, then add 0.8 - 1.0 mL of pyruvic acid, and reflux for 3 - 6 h under nitrogen protection until the reaction ends; cool the product mixture to 18 - 25 °C, then perform suction filtration, wash the filter cake with 50 mL of deionized water each time for 3 - 5 times, and dry to obtain the yellow solid product 1-phenyl-3-methyl-2(1H)-quinoxalinone, and further purify the product by recrystallization with absolute ethanol; Step 2: Under nitrogen protection, add 1 - 1.2 mmol of 4-(4-pyridyl)benzaldehyde to 5 - 10 mL of anhydrous tetrahydrofuran, stir at 25 - 30 °C for 5 - 10 min, then dropwise add 1 mL of boron trifluoride diethyl ether solution with a mass fraction of 40 - 50% to form a mixed solution. After stirring the mixed solution for 20 - 30 min, add 1 mmol of 1-phenyl-3-methyl-2(1H)-quinoxalinone, and reflux for 4 - 6 h until the reaction ends; Step 3: Add 150 mL of deionized water to the reaction mixture, adjust the pH of the solution to 7 - 8 with saturated sodium bicarbonate aqueous solution, then extract with 50 mL of ethyl acetate each time for 3 times, combine the organic phases, rotary evaporate and concentrate to obtain the solid crude product, and finally separate and purify by column chromatography to obtain the quinoxalinone compound containing styrylpyridine.

3. The method according to claim 2, wherein: In Step 3, the eluent for column chromatography separation is dichloromethane and ethyl acetate, and the volume ratio is 4 - 6:1.

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