12-chlorobenzo [f] benzofuro [3, 2-c] isoquinoline as well as preparation method and application thereof

Abstract

The invention relates to the technical field of organic synthesis, in particular to 12-chlorobenzo [f] benzofuro [3, 2-c] isoquinoline as well as a preparation method and application thereof. The invention synthesizes an organic compound 12-chlorobenzo [f] benzofuro [3, 2-c] isoquinoline which is an organic intermediate and a material intermediate with a very good application prospect, fills the blank of the prior art, and has a wide application prospect. The compound has a fluorescent property and contains a plurality of active sites, and the active sites can quickly react with pollutants in the environment. Therefore, the 12-chlorobenzo [f] benzofuro [3, 2-c] isoquinoline compound can be used as a high-sensitivity and high-selectivity fluorescent probe for detecting antibiotics in the environment.

Description

Technical Field

[0001] The present invention relates to the technical field of organic synthesis, and in particular to a 12-chlorobenzo[f]benzofuro[3,2-c]isoquinoline, a preparation method thereof, and an application thereof. Background Art

[0002] Antibiotic pollution has become an important environmental problem in the world today. Due to the characteristics of large biological toxicity and containing antibacterial substances in antibiotic wastewater, traditional physical adsorption methods and biological treatment methods have poor effects in treating such refractory toxic organic wastewater, especially wastewater containing residual trace antibiotics. Norfloxacin (NOR) belongs to the fluoroquinolone drugs and is commonly used for preventing and treating animal inflammations, such as respiratory and skin infections. However, due to the overuse of NOR by people, the content of NOR in the environment far exceeds the standard. After entering the environment, norfloxacin will undergo a series of migration and transformation processes, including adsorption, degradation, photolysis, and hydrolysis, etc. Due to its stable structure, norfloxacin is difficult to be completely degraded in the environment, easy to accumulate in soil and sediments, and enrich through the food chain, which may ultimately pose a potential threat to human health and the ecosystem.

[0003] In order to evaluate the environmental risk of norfloxacin and formulate effective pollution control strategies, it is crucial to establish a sensitive, accurate, and rapid detection method for norfloxacin in environmental samples. The matrix of environmental samples is complex, and the content of norfloxacin is usually low. Therefore, it is necessary to select appropriate sample pretreatment methods and analytical detection techniques to improve the detection sensitivity and accuracy and reduce matrix interference. The existing methods for detecting norfloxacin in the environment mainly include the following points:

[0004] (1) High-performance liquid chromatography: HPLC is currently the most widely used method for detecting norfloxacin, with advantages such as high separation efficiency, good sensitivity, and good selectivity. Commonly used detectors include ultraviolet detectors, fluorescence detectors, and mass spectrometric detectors.

[0005] (2) Liquid chromatography-mass spectrometry: LC-MS combines the high separation ability of liquid chromatography and the high sensitivity and high selectivity of mass spectrometry, and is one of the most sensitive and accurate methods for detecting norfloxacin at present, suitable for the detection of trace norfloxacin in complex matrices.

[0006] (3) Immunoassay: Immunoassay is based on the specific reaction of antigen and antibody, with advantages such as simple operation, rapidity, and low cost, and is suitable for on-site rapid screening. Commonly used immunoassay methods include enzyme-linked immunosorbent assay and fluorescence immunoassay.

[0007] (4) Electrochemical analysis method: The electrochemical analysis method utilizes the oxidation-reduction reaction of norfloxacin on the electrode surface for detection, and has the advantages of high sensitivity, good selectivity, and simple operation. Commonly used electrochemical analysis methods include cyclic voltammetry, differential pulse voltammetry, and square wave voltammetry.

[0008] Fluorescence analysis method shows great potential in the field of antibiotic detection due to its advantages such as high sensitivity, simple operation, and fast response speed. This technique is based on the fluorescence characteristics of the target molecule or its derivatives (such as excitation / emission wavelength, fluorescence lifetime, etc.), and qualitative or quantitative analysis is achieved through the change of fluorescence signals. Some antibiotics (such as tetracyclines, quinolones) have fluorescence characteristics themselves and can be directly detected; while other antibiotics (such as β-lactams, aminoglycosides) can be indirectly detected through fluorescence labeling, nanomaterial enhancement, or molecular imprinting technology. In recent years, the introduction of novel fluorescence probes (such as carbon quantum dots, metal-organic framework materials) and signal amplification strategies (such as fluorescence resonance energy transfer, ratio fluorescence) has further improved the specificity and anti-interference ability of the method.

[0009] However, in practical applications, due to the low content of residual antibiotics in actual samples and the complexity of coexisting substances, the above methods require complex sample pretreatment, especially relying on expensive experimental instruments and having high requirements for detection conditions. Therefore, it is of great practical significance to establish a rapid, highly sensitive, and highly selective antibiotic detection method. Summary of the Invention

[0010] The first aspect of the present invention provides a preparation method of 12-chlorobenzo[f]benzofuro[3,2-c]isoquinoline, comprising the following steps:

[0011] S1. Synthesize 2-chloro-3-fluoro-4-iodo-5-methylpyridine from 2-chloro-3-fluoro-5-methylpyridine and iodine.

[0012] S2. Synthesize 2-(2-chloro-3-fluoro-5-methylpyridin-4-yl)benzaldehyde from 2-chloro-3-fluoro-4-iodo-5-methylpyridine and (2-formylphenyl)boronic acid.

[0013] S3. Synthesize 2-(2-(3-chloro-2-methoxyphenyl)-3-fluoro-5-methylpyridin-4-yl)benzaldehyde from 2-(2-chloro-3-fluoro-5-methylpyridin-4-yl)benzaldehyde and (3-chloro-2-methoxyphenyl)boronic acid.

[0014] S4. Synthesize 2-(2-(3-chloro-2-hydroxyphenyl)-3-fluoro-5-methylpyridin-4-yl)benzaldehyde from 2-(2-(3-chloro-2-methoxyphenyl)-3-fluoro-5-methylpyridin-4-yl)benzaldehyde and boron tribromide.

[0015] S5. Synthesis of 2-(6-chloro-3-methylbenzofuro[3,2-b]pyridin-4-yl)benzaldehyde from 2-(2-(3-chloro-2-hydroxyphenyl)-3-fluoro-5-methylpyridin-4-yl)benzaldehyde and potassium carbonate;

[0016] S6. Synthesis of 12-chlorobenzo[f]benzofuro[3,2-c]isoquinoline from 2-(6-chloro-3-methylbenzofuro[3,2-b]pyridin-4-yl)benzaldehyde and sodium tert-butoxide.

[0017] In some embodiments, the ratio of 2-chloro-3-fluoro-5-methylpyridine to iodine is 400 g : (3.0 - 3.1) mol.

[0018] In some embodiments, the molar ratio of 2-chloro-3-fluoro-4-iodo-5-methylpyridine to (2-formylphenyl)boronic acid is (3.0 - 3.5) : (3.5 - 4.0).

[0019] In some embodiments, the molar ratio of 2-(2-chloro-3-fluoro-5-methylpyridin-4-yl)benzaldehyde to (3-chloro-2-methoxyphenyl)boronic acid is (7.5 - 8.0) : (8.0 - 8.5).

[0020] In some embodiments, the molar ratio of 2-(2-(3-chloro-2-methoxyphenyl)-3-fluoro-5-methylpyridin-4-yl)benzaldehyde to boron tribromide is (6.0 - 6.5) : (12.5 - 13.0).

[0021] In some embodiments, the molar ratio of 2-(2-(3-chloro-2-hydroxyphenyl)-3-fluoro-5-methylpyridin-4-yl)benzaldehyde to potassium carbonate is (5.0 - 5.5) : (26 - 30).

[0022] In some embodiments, the molar ratio of 2-(6-chloro-3-methylbenzofuro[3,2-b]pyridin-4-yl)benzaldehyde to sodium tert-butoxide is (5.0 - 5.5) : (13 - 15).

[0023] The second aspect of the present invention provides a 12-chlorobenzo[f]benzofuro[3,2-c]isoquinoline obtained by the above synthesis method.

[0024] The third aspect of the present invention provides an application of 12-chlorobenzo[f]benzofuro[3,2-c]isoquinoline in the fluorescence detection of the antibiotic norfloxacin.

[0025] In some embodiments, the fluorescence detection method includes: blending 12-chlorobenzo[f]benzofuro[3,2-c]isoquinoline with norfloxacin and measuring the fluorescence intensity of the mixture.

[0026] The synthetic route of the present invention is as follows:

[0027]

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] 1. The present invention synthesizes an organic compound 12-chlorobenzo[f]benzofuro[3,2-c]isoquinoline, which is a very promising organic intermediate and material intermediate, filling the gap in the prior art and having broad application prospects.

[0030] 2. The 12-chlorobenzo[f]benzofuro[3,2-c]isoquinoline compound synthesized by the present invention has fluorescence properties, and the compound contains multiple active sites, which can rapidly interact with pollutants in the environment. Therefore, the 12-chlorobenzo[f]benzofuro[3,2-c]isoquinoline compound can be used as a highly sensitive and selective fluorescence probe to detect antibiotics in the environment.

[0031] 3. The present invention also provides a method for detecting norfloxacin in the environment, which can be realized without expensive experimental instruments and operation steps, and is convenient and fast. Description of the Drawings

[0032] Figure 1 It is a diagram of the fluorescence sensing effect of compound 1 on various antibiotics.

[0033] Figure 2 It is a detailed titration result diagram of antibiotic NOR.

[0034] Figure 3 It is a linear relationship diagram shown by NOR within the range of 60 ppm.

[0035] Figure 4 It is a diagram of the influence of the detection of NOR by compound 1 in the presence of coexisting ions. Detailed Embodiments

[0036] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0037] Example 1

[0038] This example provides a 12-chlorobenzo[f]benzofuro[3,2-c]isoquinoline, and the preparation method includes the following steps:

[0039] S1. Synthesis of 2-chloro-3-fluoro-4-iodo-5-methylpyridine from 2-chloro-3-fluoro-5-methylpyridine and iodine

[0040] Add diisopropylamine (392 g, 3.87 mol) and 4 L of tetrahydrofuran into a 5 L reactor in sequence. Cool down the temperature to -78 °C, and dropwise add n-butyllithium (1.4 L, 3.5 mol). After the addition, maintain the reaction at -78 °C for 1 hour. Add 2-chloro-3-fluoro-5-methylpyridine (400 g), and maintain the temperature at -78 °C for 1 hour. Add iodine (765 g, 3.01 mol), warm back to room temperature and react for 16 hours. Add saturated ammonium chloride to quench the reaction, then extract with ethyl acetate. After drying the organic phase, obtain 600 g of the pale yellow target product 2-chloro-3-fluoro-4-iodo-5-methylpyridine by column chromatography, with a yield of 80.4%.

[0041]

[0042] S2. Synthesis of 2-(2-chloro-3-fluoro-5-methylpyridin-4-yl)benzaldehyde from 2-chloro-3-fluoro-4-iodo-5-methylpyridine and (2-formylphenyl)boronic acid

[0043] Add 2-chloro-3-fluoro-4-iodo-5-methylpyridine (858 g, 3.16 mol), 1,1-bis(diphenylphosphino)ferrocene dichloropalladium (115 g, 157.5 mmol), tripotassium phosphate (1341 g, 6.32 mol), (2-formylphenyl)boronic acid (569 g, 3.78 mol), 5.2 L of 1,4-dioxane and 1.3 L of water into a 10 L reactor. Replace the gas in the system with nitrogen for 3 times. Under the protection of nitrogen, heat the system to 80 °C and react overnight. Cool to room temperature, dilute with water, extract with dichloromethane. Dry the organic phase with anhydrous sodium sulfate, and obtain 476 g of the yellow solid target product 2-(2-chloro-3-fluoro-5-methylpyridin-4-yl)benzaldehyde by silica gel column chromatography with PE / EA = 10 / 1 - 8 / 1, with a yield of 60.3%.

[0044] 1 H NMR (400 MHz, CDCl 3 ) δ 9.38 (d, J = 8.7 Hz, 1H), 8.29 (t, J = 7.0Hz, 2H), 7.75 (d, J = 9.0 Hz, 1H), 7.68 (td, J = 8.2, 6.4 Hz, 1H), 7.46 –7.32 (m, 2H), 4.32 (s, 3H).

[0045]

[0046] S3. Synthesis of 2-(2-(3-chloro-2-methoxyphenyl)-3-fluoro-5-methylpyridin-4-yl)benzaldehyde from 2-(2-chloro-3-fluoro-5-methylpyridin-4-yl)benzaldehyde and (3-chloro-2-methoxyphenyl)boronic acid;

[0047] Add 2-(2-chloro-3-fluoro-5-methylpyridin-4-yl)benzaldehyde (190 g, 761 mmol), 1,1-bis(diphenylphosphino)ferrocene dichloropalladium(II) (27 g, 36.9 mmol), (3-chloro-2-methoxyphenyl)boronic acid (156 g, 837 mmol), sodium carbonate (161 g, 1.52 mol), 1.5 L of 1,4-dioxane and 0.4 L of water into a 2 L reactor. Replace the air with nitrogen three times, heat to 80 °C and react overnight. Cool to room temperature, then add water and extract with dichloromethane. Dry the organic phase over anhydrous sodium sulfate and perform silica gel column chromatography with PE / EA = 20 / 1 - 5 / 1 to obtain 225 g of the target product 2-(2-(3-chloro-2-methoxyphenyl)-3-fluoro-5-methylpyridin-4-yl)benzaldehyde as a yellow oil, with a yield of 83.1%.

[0048]

[0049] S4. Synthesis of 2-(2-(3-chloro-2-hydroxyphenyl)-3-fluoro-5-methylpyridin-4-yl)benzaldehyde from 2-(2-(3-chloro-2-methoxyphenyl)-3-fluoro-5-methylpyridin-4-yl)benzaldehyde and boron tribromide;

[0050] Add 2-(2-(3-chloro-2-methoxyphenyl)-3-fluoro-5-methylpyridin-4-yl)benzaldehyde (225 g, 634.4 mmol) and 1125 mL of dichloromethane into a 3 L reaction flask. Control the internal temperature at -5 - 0 °C, then dropwise add 1125 mL of a dichloromethane solution of boron tribromide (317 g, 1264.8 mmol) with the internal temperature not exceeding 0 °C, and react at 0 °C for 2 hours. After the reaction is completed, add 1 L of water at 0 °C to quench the reaction. Extract the aqueous phase with 1 L of dichloromethane, combine the organic phases, dry over anhydrous sodium sulfate and concentrate to obtain 180 g of the target product 2-(2-(3-chloro-2-hydroxyphenyl)-3-fluoro-5-methylpyridin-4-yl)benzaldehyde as a yellow solid, with a yield of 83.3%.

[0051]

[0052] S5. Synthesis of 2-(6-chloro-3-methylbenzo[f]furo[3,2-b]pyridin-4-yl)benzaldehyde from 2-(2-(3-chloro-2-hydroxyphenyl)-3-fluoro-5-methylpyridin-4-yl)benzaldehyde and potassium carbonate;

[0053] In a 3 L reaction flask, 2-(2-(3-chloro-2-hydroxyphenyl)-3-fluoro-5-methylpyridin-4-yl)benzaldehyde (180 g, 527.8 mmol), 1.8 L of N,N-dimethylformamide, and potassium carbonate (136.7 g, 2639 mmol) were successively added. The reaction system was stirred at a temperature within 55 °C for 20 hours. After the reaction was completed, the reaction solution containing the target product 2-(6-chloro-3-methylbenzofuro[3,2-b]pyridin-4-yl)benzaldehyde could be directly used for the next step of the reaction without any other operations.

[0054]

[0055] S6. Synthesis of 12-chlorobenzo[f]benzofuro[3,2-c]isoquinoline from 2-(6-chloro-3-methylbenzofuro[3,2-b]pyridin-4-yl)benzaldehyde and sodium tert-butoxide;

[0056] At an internal temperature of 55 °C, sodium tert-butoxide (126.7 g, 1319.6 mmol) was added portionwise to the reaction solution from the previous step containing 2-(6-chloro-3-methylbenzofuro[3,2-b]pyridin-4-yl)benzaldehyde (169.7 g, 527.8 mmol), and the reaction was maintained at an internal temperature of 55 °C for 20 hours. After the reaction was completed, 3.6 L of water was added to quench the reaction, and the mixture was stirred for 2 hours, filtered, the filter cake was washed with 1 L of water, the filter cake was stirred with 0.9 L of acetonitrile for half an hour, filtered, and the filter cake was dried to obtain 85 g of the crude product. The crude product was added to 0.85 L of N,N-dimethylformamide and stirred for half an hour, filtered, the filter cake was washed with 100 mL of ethanol, and after drying, 57 g of the target product, off-white solid 12-chlorobenzo[f]benzofuro[3,2-c]isoquinoline, was obtained with a yield of 35.6% and a content of 98.5%.

[0057] 1 H NMR (400 MHz, DMSO) δ 9.43 (d, J = 8.3 Hz, 1H), 9.41 (s, 1H), 8.22(dd, J = 15.7, 6.9 Hz, 3H), 8.14 (d, J = 8.8 Hz, 1H), 7.98 (t, J = 7.0 Hz,1H), 7.91 (t, J = 7.0 Hz, 1H), 7.82 (d, J = 7.1 Hz, 1H), 7.59 (t, J = 7.8 Hz,1H).

[0058]

[0059] Example 2

[0060] This example provides the application of 12-chlorobenzo[f]benzofuro[3,2-c]isoquinoline (hereinafter referred to as Compound 1) in the fluorescence detection of the antibiotic norfloxacin.

[0061] 4 mg of Compound 1 was ground and dispersed in 3.5 mL of 0.1 mol / L chloramphenicol metronidazole (CAP), penicillin G sodium (PCL), sulfadiazine (SDZ), sulfamethazine (SMZ), ornidazole (ODZ), ronidazole (RDZ), nitrofurazone (NZF), nitrofurantoin (NFT), and norfloxacin (NOR). The fluorescence intensities of various antibiotics containing Compound 1 were measured using a fluorescence spectrometer (RF-5301PC) for the experiment.

[0062] As Figure 1 shown, Compound 1 has a good fluorescence quenching effect on norfloxacin (NOR), demonstrating that Compound 1 can perform fluorescence sensing of the antibiotic norfloxacin with high selectivity and high sensitivity.

[0063] To further refine the fluorescence process of Compound 1 against the antibiotic norfloxacin, the present invention carried out a refinement titration experiment: different amounts of NOR solution were dropped into the aqueous solution containing Compound 1, and the fluorescence intensities of norfloxacin (NOR) solutions with different contents were measured using a fluorescence spectrometer (RF-5301PC).

[0064] The results are as Figure 2 shown. When the fluorescence intensity is quenched by 50%, NOR is 30 ppm at this time. Compound 1 shows a good linear relationship with the concentration of NOR in the concentration range of 60 ppm (R 2 = 0.98, Figure 3 ).

[0065] In addition, the present invention further explores the influence of Compound 1 on the detection of NOR in the presence of coexisting antibiotics. 4 mg of Compound 1 was separately dispersed into various coexisting antibiotics [NOR (1.75 mL 0.1 mol / L) + CAP (1.75 mL 0.1 mol / L), NOR (1.75 mL 0.1 mol / L) + PCL (1.75 mL 0.1 mol / L), NOR (1.75 mL 0.1 mol / L) + SDZ (1.75 mL 0.1 mol / L), NOR (1.75 mL 0.1 mol / L) + SMZ (1.75 mL 0.1 mol / L), NOR (1.75 mL 0.1 mol / L) + ODZ (1.75 mL 0.1 mol / L), NOR (1.75 mL 0.1 mol / L) + RDZ (1.75 mL 0.1 mol / L), NOR (1.75 mL 0.1 mol / L) + NZF (1.75 mL 0.1 mol / L), NOR (1.75 mL 0.1 mol / L) + NFT (1.75 mL 0.1 mol / L)], and a fluorescence spectrometer (RF-5301PC) was used in the experiment to measure the fluorescence intensity of various coexisting antibiotics containing Compound 1. As Figure 4 shown, Compound 1 has almost no influence on the detection of NOR before and after the addition of interferents. Therefore, Compound 1 has high selectivity, good anti-interference ability and high sensitivity for the detection of NOR.

[0066] The above are the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A method for preparing 12-chlorobenzo[f]benzofurano[3,2-c]isoquinoline, characterized in that: The steps include: S1. Synthesis of 2-chloro-3-fluoro-4-iodo-5-methylpyridine from 2-chloro-3-fluoro-5-methylpyridine and iodine; S2. Synthesis of 2-(2-chloro-3-fluoro-5-methylpyridin-4-yl)benzaldehyde from 2-chloro-3-fluoro-4-iodo-5-methylpyridine and (2-formylphenyl)boronic acid; S3. Synthesis of 2-(2-(3-chloro-2-methoxyphenyl)-3-fluoro-5-methylpyridin-4-yl)benzaldehyde from 2-(2-chloro-3-fluoro-5-methylpyridin-4-yl)benzaldehyde and (3-chloro-2-methoxyphenyl)boric acid; S4. Synthesis of 2-(2-(3-chloro-2-hydroxyphenyl)-3-fluoro-5-methylpyridin-4-yl)benzaldehyde from 2-(2-(3-chloro-2-methoxyphenyl)-3-fluoro-5-methylpyridin-4-yl)benzaldehyde and boron tribromide; S5. Synthesis of 2-(6-chloro-3-methylbenzofurano[3,2-b]pyridin-4-yl)benzaldehyde from 2-(2-(3-chloro-2-hydroxyphenyl)-3-fluoro-5-methylpyridin-4-yl)benzaldehyde and potassium carbonate; S6. Synthesis of 12-chlorobenzo[f]benzofurano[3,2-c]isoquinoline from 2-(6-chloro-3-methylbenzofurano[3,2-b]pyridin-4-yl)benzaldehyde and sodium tert-butoxide.

2. The preparation method according to claim 1, characterized in that: The ratio of the 2-chloro-3-fluoro-5-methylpyridine to the elemental iodine is 400 g: (3.0-3.1) mol.

3. The preparation method according to claim 1, characterized in that: The molar ratio of the 2-chloro-3-fluoro-4-iodo-5-methylpyridine to (2-formylphenyl)boric acid is (3.0-3.5): (3.5-4.0).

4. The preparation method according to claim 1, characterized in that: The molar ratio of the 2-(2-chloro-3-fluoro-5-methylpyridin-4-yl)benzaldehyde to (3-chloro-2-methoxyphenyl)boric acid is (7.5-8.0):(8.0-8.5).

5. The preparation method according to claim 1, characterized in that: The molar ratio of the 2-(2-(3-chloro-2-methoxyphenyl)-3-fluoro-5-methylpyridin-4-yl)benzaldehyde to boron tribromide is (6.0-6.5):(12.5-13.0).

6. The preparation method according to claim 1, characterized in that: The molar ratio of the 2-(2-(3-chloro-2-hydroxyphenyl)-3-fluoro-5-methylpyridin-4-yl)benzaldehyde to potassium carbonate is (5.0-5.5):(26-30).

7. The preparation method according to claim 1, characterized in that: The molar ratio of the 2-(6-chloro-3-methylbenzofurano[3,2-b]pyridin-4-yl)benzaldehyde to sodium tert-butoxide is (5.0-5.5):(13-15).

8. A 12-chlorobenzo[f]benzofurano[3,2-c]isoquinoline, characterized in that The 12-chlorobenzo[f]benzofurano[3,2-c]isoquinoline has the following structural formula: 。 9. An application of 12-chlorobenzo[f]benzofurano[3,2-c]isoquinoline, characterized in that: Application in fluorescence detection of the antibiotic norfloxacin.

10. The use according to claim 9, characterized in that: The fluorescence detection method comprises: mixing 12-chlorobenzo[f]benzofuran[3,2-c]isoquinoline with norfloxacin, and measuring the fluorescence intensity of the mixed solution.

Images