12-chlorobenzo[f]benzofurano[3,2-c]isoquinoline and its preparation method and application

Abstract

The present invention relates to the field of organic synthesis technology, and in particular to a kind of 12-chlorobenzo [f] benzofuran [3,2-c] isoquinoline and its preparation method and application. The present invention synthesizes a kind of organic compound 12-chlorobenzo [f] benzofuran [3,2-c] isoquinoline, is very promising organic intermediate, material intermediate, fills the gap of prior art, has broad application prospect. The compound has fluorescent properties, and contains multiple active sites in the compound, and these active sites can react quickly with pollutants in the environment. Therefore, 12-chlorobenzo [f] benzofuran [3,2-c] isoquinoline compound can be used as a highly sensitive, highly selective fluorescent probe to detect antibiotics in the environment.

Description

Technical Field

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

[0002] Antibiotic pollution has become a significant environmental issue worldwide. Due to the high biotoxicity and presence of antibacterial substances in antibiotic wastewater, traditional physical adsorption and biological treatment methods are ineffective in treating this difficult-to-degrade toxic organic wastewater, especially those containing trace amounts of residual antibiotics. Norfloxacin (NOR), a fluoroquinolone, is commonly used to prevent and treat inflammatory conditions in animals, such as respiratory and skin infections. However, excessive NOR use has led to levels in the environment exceeding recommended levels. Once released into the environment, norfloxacin undergoes a series of migration and transformation processes, including adsorption, degradation, photolysis, and hydrolysis. Due to its stable structure, norfloxacin is difficult to fully degrade in the environment, easily accumulating in soil and sediments and enriching through the food chain, potentially posing a potential threat to human health and ecosystems.

[0003] To assess the environmental risks of norfloxacin and develop effective pollution control strategies, it is crucial to establish sensitive, accurate, and rapid methods for detecting norfloxacin in environmental samples. Environmental sample matrices are complex, and norfloxacin levels are typically low. Therefore, appropriate sample pretreatment methods and analytical detection technologies are necessary to improve detection sensitivity and accuracy and reduce matrix interference. Existing methods for detecting norfloxacin in the environment primarily include the following:

[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 spectrometry detectors.

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

[0006] (3) Immunoassay: Immunoassay is based on antigen-antibody specific reactions and has the advantages of being simple, rapid, and low-cost, making it suitable for rapid on-site screening. Commonly used immunoassay methods include enzyme-linked immunosorbent assay (ELISA) and fluorescent immunoassay.

[0007] (4) Electrochemical analysis: Electrochemical analysis utilizes the redox 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, due to its high sensitivity, ease of use, and rapid response, holds great promise for antibiotic detection. This technique leverages the fluorescence properties of target molecules or their derivatives (e.g., excitation / emission wavelengths, fluorescence lifetime), enabling qualitative or quantitative analysis through changes in the fluorescence signal. Some antibiotics (e.g., tetracyclines and quinolones) inherently exhibit fluorescence properties and can be detected directly, while others (e.g., β-lactams and aminoglycosides) can be detected indirectly through fluorescent labeling, nanomaterial enhancement, or molecular imprinting techniques. In recent years, the introduction of novel fluorescent probes (e.g., carbon quantum dots and metal-organic frameworks) and signal amplification strategies (e.g., fluorescence resonance energy transfer and ratiometric fluorescence) have further enhanced the specificity and anti-interference capabilities of these methods.

[0009] However, in practical applications, since the residual antibiotic content in actual samples is often very low and the coexisting substances are complex, the sample pretreatment of the above method is complicated, 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 method for preparing 12-chlorobenzo[f]benzofurano[3,2-c]isoquinoline, comprising the following steps:

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

[0012] 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;

[0013] 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;

[0014] 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;

[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 elemental 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 12-chlorobenzo[f]benzofurano[3,2-c]isoquinoline, which is obtained by the above-mentioned synthesis method.

[0024] The third aspect of the present invention provides a use of 12-chlorobenzo[f]benzofurano[3,2-c]isoquinoline for fluorescent detection of the antibiotic norfloxacin.

[0025] In some embodiments, the fluorescence detection method comprises: mixing 12-chlorobenzo[f]benzofurano[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]benzofurano[3,2-c]isoquinoline, which is an organic intermediate and material intermediate with great application prospects, fills the gap in the existing technology, and has broad application prospects.

[0030] 2. The 12-chlorobenzo[f]benzofurano[3,2-c]isoquinoline compound synthesized in this invention exhibits fluorescent properties and contains multiple active sites that can rapidly interact with environmental pollutants. Therefore, the 12-chlorobenzo[f]benzofurano[3,2-c]isoquinoline compound can be used as a highly sensitive and selective fluorescent probe for detecting antibiotics in the environment.

[0031] 3. The present invention also provides a method for detecting norfloxacin in the environment, which can achieve detection without expensive experimental instruments and operating steps, and is convenient and fast. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is the fluorescence sensing result of compound 1 on various antibiotics.

[0033] Figure 2 This is the result of the refined titration of the antibiotic NOR.

[0034] Figure 3 This is the linear relationship graph of NOR in the range of 60 ppm.

[0035] Figure 4 This is a diagram showing the effect of the presence of coexisting ions on the detection of NOR by compound 1. DETAILED DESCRIPTION

[0036] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0037] Example 1

[0038] This embodiment provides a 12-chlorobenzo[f]benzofurano[3,2-c]isoquinoline, the preparation method of which comprises 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] To a 5L reactor, diisopropylamine (392 g, 3.87 mol) and 4L of tetrahydrofuran were added sequentially. The temperature was cooled to -78°C, and n-butyllithium (1.4 L, 3.5 mol) was added dropwise. After the addition was complete, the temperature was maintained at -78°C for 1 hour. 2-Chloro-3-fluoro-5-methylpyridine (400 g) was added, and the temperature was maintained at -78°C for 1 hour. Iodine (765 g, 3.01 mol) was added, and the temperature was returned to room temperature for 16 hours. The reaction was quenched by adding saturated ammonium chloride, and the mixture was extracted with ethyl acetate. The organic phase was dried and purified by column chromatography to obtain 600 g of the desired product, 2-chloro-3-fluoro-4-iodo-5-methylpyridine, as a pale yellow product in an 80.4% yield.

[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] To a 10-L reactor, add 2-chloro-3-fluoro-4-iodo-5-methylpyridine (858 g, 3.16 mol), 1,1-bis(diphenylphosphino)diborane iron palladium dichloride (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. The atmosphere was purged with nitrogen three times. Under nitrogen protection, the system was warmed to 80°C and reacted overnight. The reaction mixture was cooled to room temperature, diluted with water, and extracted with dichloromethane. The organic phase was dried over anhydrous sodium sulfate and purified by silica gel column chromatography with a PE / EA ratio of 10 / 1 to 8 / 1 to obtain 476 g of the desired product, 2-(2-chloro-3-fluoro-5-methylpyridin-4-yl)benzaldehyde, as a yellow solid in a 60.3% yield.

[0044] 1 H NMR (400 MHz, CDCl3) 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)boric acid;

[0047] To a 2L reactor, 2-(2-chloro-3-fluoro-5-methylpyridin-4-yl)benzaldehyde (190 g, 761 mmol), 1,1-bis(diphenylphosphino)diphenylferric palladium dichloride (27 g, 36.9 mmol), (3-chloro-2-methoxyphenyl)boric acid (156 g, 837 mmol), sodium carbonate (161 g, 1.52 mol), 1.5 L 1,4-dioxane and 0.4 L water were added. The atmosphere was replaced with nitrogen three times, the temperature was raised to 80°C, and the reaction was allowed to proceed overnight. The reaction mixture was cooled to room temperature, and then water was added and extracted with dichloromethane. The organic phase was dried over anhydrous sodium sulfate and chromatographed on a silica gel column with PE / EA = 20 / 1-5 / 1 to give 225 g of the target product 2-(2-(3-chloro-2-methoxyphenyl)-3-fluoro-5-methylpyridin-4-yl)benzaldehyde as a yellow oil in 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] To a 3 L reaction flask, 2-(2-(3-chloro-2-methoxyphenyl)-3-fluoro-5-methylpyridin-4-yl)benzaldehyde (225 g, 634.4 mmol) and 1125 mL of dichloromethane were added. The internal temperature was controlled at -5-0°C, and then 1125 mL of a dichloromethane solution of boron tribromide (317 g, 1264.8 mmol) was added dropwise. The internal temperature did not exceed 0°C, and the mixture was reacted at 0°C for 2 hours. After completion of the reaction, 1 L of water was added at 0°C to quench the reaction. The aqueous phase was extracted with 1 L of dichloromethane, and the organic phases were combined, dried over anhydrous sodium sulfate, and concentrated to give 180 g of the target product, 2-(2-(3-chloro-2-hydroxyphenyl)-3-fluoro-5-methylpyridin-4-yl)benzaldehyde, as a yellow solid in a yield of 83.3%.

[0051]

[0052] 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;

[0053] To a 3 L reaction flask, add 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) in sequence. Maintain stirring at 55°C for 20 hours. Upon completion, the reaction solution containing the target product, 2-(6-chloro-3-methylbenzofuro[3,2-b]pyridin-4-yl)benzaldehyde, can be used directly in the next step without further manipulation.

[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 mixture from the previous step containing 2-(6-chloro-3-methylbenzofuro[3,2-b]pyridin-4-yl)benzaldehyde (169.7 g, 527.8 mmol). The reaction was maintained at 55°C for 20 hours. After completion, the reaction was quenched by adding 3.6 L of water, stirred for 2 hours, filtered, and the filter cake rinsed with 1 L of water. The filter cake was stirred with 0.9 L of acetonitrile for half an hour, filtered, and dried to yield 85 g of the crude product. The crude product was added to 0.85 L of N,N-dimethylformamide, stirred for half an hour, filtered, and the filter cake rinsed with 100 mL of ethanol. After drying, the target product, 12-chlorobenzo[f]benzofuro[3,2-c]isoquinoline, was obtained as an off-white solid (57 g). The yield was 35.6% and the content was 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 use of 12-chlorobenzo[f]benzofurano[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), respectively. The fluorescence intensity of various antibiotics containing compound 1 was measured using a fluorescence spectrometer (RF-5301PC).

[0062] like Figure 1 As shown, compound 1 has a good fluorescence quenching effect on norfloxacin (NOR), which proves that compound 1 can be used for highly selective and sensitive fluorescence sensing of the antibiotic norfloxacin.

[0063] In order to further refine the fluorescence process of compound 1 on the antibiotic norfloxacin, the present invention carried out a refined titration experiment: NOR solutions with different contents were dropped into an aqueous solution containing compound 1, and the fluorescence intensity of the norfloxacin (NOR) solutions with different contents was measured using a fluorescence spectrometer (RF-5301PC).

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

[0065] In addition, the present invention continues to explore the effect of compound 1 on NOR detection in the presence of coexisting antibiotics. 4 mg of compound 1 was 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(1.75mL 0.1 mol / L), NOR(1.75mL 0.1 mol / L)+NFT(1.75mL 0.1mol / L)], and the fluorescence intensity of various coexisting antibiotics containing compound 1 was measured using a fluorescence spectrometer (RF-5301PC). Figure 4 As shown in the figure, before and after the addition of interfering substances, compound 1 has almost no effect on the detection of NOR. Therefore, compound 1 has high selectivity, good anti-interference and high sensitivity for the detection of NOR.

[0066] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for preparing 12-chlorobenzo[f]benzofuro[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-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; 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; The 12-chlorobenzo[f]benzofurano[3,2-c]isoquinoline has the following structural formula: 。 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-methylbenzofuro[3,2-b]pyridin-4-yl)benzaldehyde to sodium tert-butoxide is (5.0-5.5):(13-15).

8. A 12-chlorobenzo[f]benzofuro[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]benzofuro[3,2-c]isoquinoline, characterized in that: the antibiotic norfloxacin, used in a fluorescence detection setting; The 12-chlorobenzo[f]benzofurano[3,2-c]isoquinoline has the following structural formula: 。 10. The use according to claim 9, characterized in that The fluorescence detection method comprises: mixing 12-chlorobenzo[f]benzofurano[3,2-c]isoquinoline with norfloxacin in the environment, and measuring the fluorescence intensity of the mixed solution.

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