Fluorinated benzoxazole compounds and synthesis methods thereof

Abstract

The present invention discloses a fluorinated benzoxazole compound and a synthesis method thereof. The structure of the compound is: wherein R is -H, -CH 3 ,‑C(CH 3 ) 3 , -Cl or -Br. The present invention realizes the synthesis of fluorinated benzoxazole compounds promoted by visible light. The method of the present invention has the characteristics of mild conditions, simple operation, one-pot reaction, simple post-treatment, high yield, etc. The unique function of the fluorinated benzoxazole compound of the present invention, the benzoxazole derivatives prepared by using the fluorinated functional group have important physiological activity, the introduction of fluorinated functional groups can improve the lipophilicity, membrane permeability and antioxidant properties of the molecule, and can also improve the metabolic stability and efficacy of the drug molecule.

Description

Technical Field

[0001] The invention relates to a fluorine-containing benzoxazole compound and a synthesis method thereof, and is applied to the technical field of pharmaceutical intermediate materials and raw material medicines. Background Art

[0002] Compounds containing 1,3-benzoxazole skeletons have special structures and physiological activities. Especially after the introduction of fluorine-containing groups, their physical and chemical properties can be adjusted and their biological activity can be improved. Therefore, they are widely used in medicine, pesticides and functional materials. As a bioelectronic isostere of structures such as methylene, hydroxyl, oxygen atom, and carbonyl, the geminal difluoromethyl group is often used in the design of bioactive molecules. Introducing it into compounds containing 1,3-benzoxazole skeletons has a high application value in medicinal chemistry. Compared with the structure with methylene as the molecular bridge chain, the anti-HIV activity of geminal difluoromethylene as the molecular bridge chain is increased by dozens of times. For example, compound A has the following structure:

[0003]

[0004] 2-(Bromodifluoromethyl)benzoxazole is a class of fluorinated building blocks with great application value. It can be used to obtain highly active fluorinated organic molecules through coupling reactions with geminal difluoromethylene groups and other compounds. However, the existing methods for preparing fluorinated benzoxazole drugs or agents are complicated, the yield is not ideal, the cost is high, and they cannot meet the application requirements of medicine, pesticides, and functional materials. Summary of the invention

[0005] In order to solve the problems of the prior art, the purpose of the present invention is to overcome the shortcomings of the existing technology, provide a fluorinated benzoxazole compound and a synthesis method thereof, and synthesize a new fluorinated benzoxazole compound. The present invention develops a visible light-promoted synthesis method of a fluorinated benzoxazole compound. There is no report on this type of fluorinated benzoxazole compound. There is no report on the synthesis method of this type of compound.

[0006] In order to achieve the above invention purpose, the invention concept of the present invention is:

[0007] The present invention adopts the following reaction equation:

[0008]

[0009] Wherein: R=-H, -CH3, -C(CH3)3, -Cl or -Br.

[0010] According to the above inventive concept, the present invention adopts the following technical solution:

[0011] A fluorine-containing benzoxazole compound, the structure of the compound is:

[0012]

[0013] Wherein, R is -H, -CH3, -C(CH3)3, -Cl or -Br.

[0014] Preferably, a fluorinated heterocyclic building block substituted with monobromodifluoromethyl is reacted with methyl acrylate under photocatalytic conditions, and a photosensitizer, a hydrogen source, a base and a solvent are added to synthesize a fluorinated benzoxazole compound in one step.

[0015] A method for preparing the fluorinated benzoxazole compound of the present invention comprises the following steps:

[0016] (1) Preparation of reactant mixed solution system:

[0017] Adding a fluorinated heterocyclic building block substituted with monobromodifluoromethyl, methyl acrylate, a photosensitizer, a hydrogen source and a base into a reaction tube, adding a solvent into the reaction tube, protecting with nitrogen, and tightening the piston of the reaction tube to obtain a reactant mixed solution system;

[0018] (2) Preparation of fluorinated benzoxazole compounds:

[0019] At room temperature, the reactant mixed solution system is irradiated with a blue LED lamp for 12 to 36 hours. After the reaction is completed, the solvent is removed, and the mixture is extracted with ethyl acetate and saturated brine. The organic phase is concentrated under reduced pressure, and the crude product is purified by column chromatography to obtain a fluorinated benzoxazole compound.

[0020] Preferably, in the step (1), the molar ratio of the bromodifluoromethyl-substituted fluorinated heterocyclic building block, methyl acrylate, photosensitizer, hydrogen source and base is 1-2:1:0.01-2:1-2:1.

[0021] Preferably, in step (1), the structure of the fluorinated heterocyclic building block substituted with bromodifluoromethyl is: Wherein, R is -H, -CH3, -C(CH3)3, -Cl or -Br.

[0022] Preferably, in step (1), the structural formula of the methyl acrylate is

[0023] Preferably, in step (1), the structure of the photosensitizer is: fac-Ir(ppy)3, Ir(dtbbpy)(ppy)2[PF6], Ru(bpy)3Cl2·6H2O, 4CzIPN, At least one of .

[0024] Preferably, in step (1), the hydrogen source is tris(trimethylsilyl)silane, triethylsilane, ethyl mercaptoacetate, At least one of .

[0025] Preferably, in step (1), the base is at least one of triethylamine, N,N-diisopropylethylamine, pyridine, potassium carbonate and sodium bicarbonate.

[0026] Preferably, in step (1), the solvent is at least one of 1,4-dioxane, acetonitrile, acetone, tetrahydrofuran, dimethyl sulfoxide, 1,2-dichloroethane and isopropanol.

[0027] Preferably, in step (2), the eluent is a mixed solvent of petroleum ether and ethyl acetate in a volume ratio of 10:1.

[0028] Compared with the prior art, the present invention has the following obvious outstanding substantive features and significant advantages:

[0029] 1. The present invention synthesizes a series of fluorinated benzoxazole compounds in one pot by combining a fluorinated heterocyclic building block substituted with bromodifluoromethyl and methyl acrylate under photocatalysis, adding a photosensitizer, a hydrogen source, a base and a solvent;

[0030] 2. The raw materials for synthesizing the fluorinated benzoxazole compound of the present invention are cheap and readily available, and the cost is low;

[0031] 3. The method of the present invention has the characteristics of simple operation, mild conditions, excellent functional group compatibility and high yield. DETAILED DESCRIPTION

[0032] In the following embodiment, a fluorinated benzoxazole compound has the structure:

[0033]

[0034] Wherein, R is -H, -CH3, -C(CH3)3, -Cl or -Br.

[0035] The preferred examples of the present invention are described below. It should be understood that the preferred examples described herein are limited to describing and explaining the present invention and are not intended to limit the present invention. In order to enable the public to have a full understanding of the present invention, specific details are described in detail in the preferred embodiments of the present invention.

[0036] The above scheme is further described below in conjunction with specific implementation examples. The preferred embodiments of the present invention are described in detail as follows:

[0037] Embodiment 1

[0038] In this embodiment, a method for preparing a fluorinated benzoxazole compound, preparing methyl 4,4-difluoro-4-(benzoxazole-2-yl)butyrate, comprises the following steps:

[0039] (1) Preparation of reactant mixed solution system:

[0040] In a 25 ml reaction tube, 2-(bromodifluoromethyl)benzoxazole (1.85 g, 7.5 mmol), methyl acrylate (0.43 g, 5.0 mmol), 2,6-dimethyl-1,4-dihydro-3,5-pyridinedicarboxylic acid diethyl ester (1.90 g, 7.5 mmol), triethylamine (0.51 g, 5.0 mmol) were added in sequence, and finally 10 ml of 1,4-dioxane solvent was added. Under nitrogen protection, the piston of the reaction tube was tightened to obtain a reactant mixed solution system;

[0041] (2) Preparation of fluorinated benzoxazole compounds:

[0042] At room temperature, the reactant mixed solution system was irradiated with a 10W 465nm blue light LED lamp for 24 hours. After the reaction, the solvent was removed, extracted with ethyl acetate and saturated brine, and the organic phase was concentrated under reduced pressure. The crude product was purified by silica gel column chromatography. The eluent was a mixed solvent of petroleum ether and ethyl acetate in a volume ratio of 10:1 to obtain 1.16 g of methyl 4,4-difluoro-4-(benzoxazol-2-yl)butyrate with a yield of 91%.

[0043] Experimental test analysis:

[0044] In this embodiment, 4,4-difluoro-4-(benzoxazol-2-yl)butyric acid methyl ester has the structure of:

[0045]

[0046] Molecular formula: C 12 H 11 F2NO3

[0047] Chinese name: 4,4-difluoro-4-(benzoxazol-2-yl)butyric acid methyl ester

[0048] English name: methyl 4,4-difluoro-4-(benzo[d]oxazol-2-yl)butanoate

[0049] Molecular weight: 255

[0050] Appearance: Colorless oily liquid

[0051] H NMR (500 MHz, CDCl3): δppm 7.82-7.80 (m, 1H), 7.63-7.61 (m, 1H), 7.46 (td, J = 7.7, 1.3 Hz, 1H), 7.41 (td, J = 7.7, 1.2 Hz, 1H), 3.69 (s, 3H), 2.88-2.77 (m, 2H), 2.73-2.69 (m, 2H). F NMR (471 MHz, CDCl3, internal standard: C6F6): δppm -98.94 (t, J = 16.0 Hz, 2F).

[0052] Carbon nuclear magnetic resonance spectrum (126 MHz, CDCl3): δ ppm 172.03, 157.44 (t, J = 33.4 Hz), 150.70, 139.95, 127.08, 125.45, 121.38, 116.16 (t, J = 241.4 Hz), 111.52, 52.11, 31.37 (t, J = 24.3 Hz), 26.92 (t, J = 4.5 Hz).

[0053] High-resolution mass spectrometry (ESI) calculated for [M+H] + C 12 H 12 F2NO3 + Theoretical value: 256.0780; measured value: 256.0780.

[0054] Embodiment 2

[0055] This embodiment is basically the same as the first embodiment, except that:

[0056] In this embodiment, a method for preparing a fluorinated benzoxazole compound, preparing methyl 4,4-difluoro-4-(5-methylbenzoxazole-2-yl)butyrate, comprises the following steps:

[0057] (1) Preparation of reactant mixed solution system:

[0058] In a 25 ml reaction tube, 2-(bromodifluoromethyl)-5-methylbenzoxazole (1.96 g, 7.5 mmol), methyl acrylate (0.43 g, 5.0 mmol), 2,6-dimethyl-1,4-dihydro-3,5-pyridinedicarboxylic acid diethyl ester (1.90 g, 7.5 mmol), triethylamine (0.51 g, 5.0 mmol) were added in sequence, and finally 10 ml of 1,4-dioxane solvent was added. Under nitrogen protection, the piston of the reaction tube was tightened to obtain a reactant mixed solution system;

[0059] (2) Preparation of fluorinated benzoxazole compounds:

[0060] At room temperature, the reactant mixed solution system was irradiated with a 10W 465nm blue light LED lamp for 24 hours. After the reaction, the solvent was removed, extracted with ethyl acetate and saturated brine, and the organic phase was concentrated under reduced pressure. The crude product was purified by silica gel column chromatography. The eluent was a mixed solvent of petroleum ether and ethyl acetate in a volume ratio of 10:1 to obtain 1.08 g of methyl 4,4-difluoro-4-(5-methylbenzoxazol-2-yl)butyrate, with a yield of 80%.

[0061] Experimental test analysis:

[0062] In this embodiment, 4,4-difluoro-4-(5-methylbenzoxazol-2-yl)butyric acid methyl ester has the structure of:

[0063]

[0064] Molecular formula: C 13 H 13 F2NO3

[0065] Chinese name: methyl 4,4-difluoro-4-(5-methylbenzo[d]oxazol-2-yl)butanoate English name: methyl 4,4-difluoro-4-(5-methylbenzo[d]oxazol-2-yl)butanoate

[0066] Molecular weight: 269

[0067] Appearance: Colorless oily liquid

[0068] H NMR (500 MHz, CDCl3): δ ppm 7.57 (t, J = 0.8 Hz, 1H), 7.47 (d, J = 8.5 Hz, 1H), 7.26 (dd, J = 8.5, 1.4 Hz, 1H), 3.68 (s, 3H), 2.86-2.76 (m, 2H), 2.72-2.68 (m, 2H), 2.48 (s, 3H).

[0069] Fluorine nuclear magnetic resonance spectrum (471 MHz, CDCl3, internal standard: C6F6): δ ppm -98.93 (t, J = 16.4 Hz, 2F).

[0070] Carbon nuclear magnetic resonance spectrum (126MHz, CDCl3): δppm 172.07, 157.50 (t, J = 33.5Hz), 148.98, 140.17, 135.48, 128.30, 121.10, 116.18 (t, J = 241.6Hz), 110.86, 52.13, 31.40 (t, J = 24.3Hz), 26.95 (t, J = 4.3Hz), 21.55.

[0071] High-resolution mass spectrometry (ESI) calculated for [M+H] + C 13 H 14 F2NO3 + Theoretical value: 270.0936; measured value: 270.0937.

[0072] Embodiment 3

[0073] This embodiment is basically the same as the above embodiment, with the following features:

[0074] In this embodiment, a method for preparing a fluorinated benzoxazole compound, preparing methyl 4,4-difluoro-4-(5-tert-butylbenzoxazole-2-yl)butyrate, comprises the following steps:

[0075] (1) Preparation of reactant mixed solution system:

[0076] In a 25 ml reaction tube, 2-(bromodifluoromethyl)-5-tert-butylbenzoxazole (2.28 g, 7.5 mmol), methyl acrylate (0.43 g, 5.0 mmol), 2,6-dimethyl-1,4-dihydro-3,5-pyridinedicarboxylic acid diethyl ester (1.90 g, 7.5 mmol), triethylamine (0.51 g, 5.0 mmol) were added in sequence, and finally 10 ml of 1,4-dioxane solvent was added. Under nitrogen protection, the piston of the reaction tube was tightened to obtain a reactant mixed solution system;

[0077] (2) Preparation of fluorinated benzoxazole compounds:

[0078] At room temperature, the reactant mixed solution system was irradiated with a 10W 465nm blue light LED lamp for 24 hours. After the reaction, the solvent was removed, and the mixture was extracted with ethyl acetate and saturated brine. The organic phase was concentrated under reduced pressure, and the crude product was purified by silica gel column chromatography. The eluent was a mixed solvent of petroleum ether and ethyl acetate in a volume ratio of 10:1 to obtain 1.28 g of methyl 4,4-difluoro-4-(5-tert-butylbenzoxazol-2-yl)butyrate, with a yield of 82%.

[0079] Experimental test analysis:

[0080] In this embodiment, 4,4-difluoro-4-(5-tert-butylbenzoxazol-2-yl)butyric acid methyl ester has the structure of:

[0081]

[0082] Molecular formula: C 16 H 19 F2NO3

[0083] Chinese name: 4,4-difluoro-4-(5-tert-butylbenzoxazol-2-yl)butyric acid methyl ester

[0084] English name: methyl 4,4-difluoro-4-(5-(tert-butyl)benzo[d]oxazol-2-yl)butanoate

[0085] Molecular weight: 311

[0086] Appearance: Colorless oily liquid

[0087] H NMR (500 MHz, CDCl3): δ ppm 7.81 (t, J = 1.3 Hz, 1H), 7.52 (d, J = 1.3 Hz, 2H), 3.69 (s, 3H), 2.87-2.77 (m, 2H), 2.72-2.69 (m, 2H), 1.38 (s, 9H).

[0088] Fluorine nuclear magnetic resonance spectrum (471 MHz, CDCl3, internal standard: C6F6): δ ppm -98.82 (t, J = 16.0 Hz, 2F).

[0089] Carbon nuclear magnetic resonance spectrum (126 MHz, CDCl3): δ ppm 172.06, 157.53 (t, J = 33.4 Hz), 149.18, 148.75, 139.93, 124.99, 117.68, 116.20 (t, J = 241.4 Hz), 110.68, 52.11, 35.11, 31.77, 31.39 (t, J = 24.3 Hz), 26.99 (t, J = 4.5 Hz).

[0090] High-resolution mass spectrometry (ESI) calculated for [M+H] + C 16 H 20 F2NO3 + Theoretical value: 312.1406; measured value: 312.1408.

[0091] Embodiment 4

[0092] This embodiment is basically the same as the above embodiment, with the following features:

[0093] In this embodiment, a method for preparing a fluorinated benzoxazole compound, preparing methyl 4,4-difluoro-4-(5-chlorobenzoxazole-2-yl)butyrate, comprises the following steps:

[0094] (1) Preparation of reactant mixed solution system:

[0095] In a 25 ml reaction tube, 2-(bromodifluoromethyl)-5-chlorobenzoxazole (2.11 g, 7.5 mmol), methyl acrylate (0.43 g, 5.0 mmol), 2,6-dimethyl-1,4-dihydro-3,5-pyridinedicarboxylic acid diethyl ester (1.90 g, 7.5 mmol), triethylamine (0.51 g, 5.0 mmol) were added in sequence, and finally 10 ml of 1,4-dioxane solvent was added. Under nitrogen protection, the piston of the reaction tube was tightened to obtain a reactant mixed solution system;

[0096] (2) Preparation of fluorinated benzoxazole compounds:

[0097] At room temperature, the reactant mixed solution system was irradiated with a 10W 465nm blue light LED lamp for 24 hours. After the reaction, the solvent was removed, extracted with ethyl acetate and saturated brine, and the organic phase was concentrated under reduced pressure. The crude product was purified by silica gel column chromatography. The eluent was a mixed solvent of petroleum ether and ethyl acetate in a volume ratio of 10:1 to obtain 1.04 g of methyl 4,4-difluoro-4-(5-chlorobenzoxazol-2-yl)butyrate with a yield of 72%.

[0098] Experimental test analysis:

[0099] In this embodiment, 4,4-difluoro-4-(5-chlorobenzoxazol-2-yl)butyric acid methyl ester has the structure of:

[0100] Molecular formula: C 12 H 10 ClF2NO3

[0101] Chinese name: 4,4-difluoro-4-(5-chlorobenzoxazol-2-yl)butyric acid methyl ester

[0102] English name: methyl 4,4-difluoro-4-(5-chlorobenzo[d]oxazol-2-yl)butanoate

[0103] Molecular weight: 289

[0104] Appearance: Colorless oily liquid

[0105] H NMR (500 MHz, CDCl3): δ ppm 7.78 (d, J = 2.1 Hz, 1H), 7.54 (dd, J = 8.8, 0.4 Hz, 1H), 7.43 (dd, J = 8.8, 2.1 Hz, 1H), 3.68 (s, 3H), 2.85-2.76 (m, 2H), 2.71-2.68 (m, 2H).

[0106] NMR fluorine spectrum (471 MHz, CDCl3): δ ppm -99.08 (t, J = 16.3 Hz, 2F).

[0107] Carbon nuclear magnetic resonance spectrum (126 MHz, CDCl3, internal standard: C6F6): δ ppm 171.93, 158.71 (t, J = 33.4 Hz), 149.26, 141.02, 131.09, 127.58, 121.33, 115.97 (t, J = 242.2 Hz), 112.36, 52.16, 31.29 (t, J = 24.2 Hz), 26.82 (t, J = 4.5 Hz).

[0108] High-resolution mass spectrometry (ESI) calculated for [M+H] + C 12 H 11 ClF2NO3 + Theoretical value: 290.0390; measured value: 290.0394.

[0109] Embodiment 5

[0110] This embodiment is basically the same as the above embodiment, with the following features:

[0111] In this embodiment, a method for preparing a fluorinated benzoxazole compound, preparing 4,4-difluoro-4-(5-bromobenzoxazole-2-yl)butyric acid methyl ester, comprises the following steps:

[0112] (1) Preparation of reactant mixed solution system:

[0113] In a 25 ml reaction tube, 2-(bromodifluoromethyl)-5-bromobenzoxazole (2.43 g, 7.5 mmol), methyl acrylate (0.43 g, 5.0 mmol), 2,6-dimethyl-1,4-dihydro-3,5-pyridinedicarboxylic acid diethyl ester (1.90 g, 7.5 mmol), triethylamine (0.51 g, 5.0 mmol) were added in sequence, and finally 10 ml of 1,4-dioxane solvent was added. Under nitrogen protection, the piston of the reaction tube was tightened to obtain a reactant mixed solution system;

[0114] (2) Preparation of fluorinated benzoxazole compounds:

[0115] At room temperature, the reactant mixed solution system was irradiated with a 10W 465nm blue light LED lamp for 24 hours. After the reaction, the solvent was removed, extracted with ethyl acetate and saturated brine, and the organic phase was concentrated under reduced pressure. The crude product was purified by silica gel column chromatography. The eluent was a mixed solvent of petroleum ether and ethyl acetate in a volume ratio of 10:1 to obtain 1.25 g of methyl 4,4-difluoro-4-(5-bromobenzoxazol-2-yl)butyrate, and the yield was 75%.

[0116] Experimental test analysis:

[0117] In this embodiment, 4,4-difluoro-4-(5-bromobenzoxazol-2-yl)butyric acid methyl ester has the structure of:

[0118]

[0119] Molecular formula: C 12 H 10 BrF2NO3

[0120] Chinese name: 4,4-difluoro-4-(5-bromobenzoxazol-2-yl)butyric acid methyl ester

[0121] English name: methyl 4,4-difluoro-4-(5-bromobenzooxazol-2-yl)butanoate

[0122] Molecular weight: 333

[0123] Appearance: Colorless oily liquid

[0124] H NMR (500 MHz, CDCl3): δ ppm 7.95 (t, J = 1.9 Hz, 1H), 7.58 (dd, J = 8.8, 1.9 Hz, 1H), 7.50 (dd, J = 8.8, 0.5 Hz, 1H), 3.69 (s, 3H), 2.86-2.76 (m, 2H), 2.72-2.68 (m, 2H).

[0125] Fluorine nuclear magnetic resonance spectrum (471 MHz, CDCl3, internal standard: C6F6): δ ppm -99.07 (t, J = 16.3 Hz, 2F).

[0126] Carbon nuclear magnetic resonance spectrum (126 MHz, CDCl3): δ ppm 171.91, 158.50 (t, J = 33.9 Hz), 149.66, 141.46, 130.27, 124.36, 118.26, 115.93 (t, J = 242.2 Hz), 112.81, 52.16, 31.28 (t, J = 24.1 Hz), 26.81 (t, J = 4.4 Hz).

[0127] High-resolution mass spectrometry (ESI) calculated for [M+H] + C 12 H 11 BrF2NO3 + Theoretical value: 333.9885; measured value: 333.9887.

[0128] The unique functions of the fluorinated benzoxazole compounds in the above embodiments, the benzoxazole derivatives prepared by using them have important physiological activities, and the introduction of fluorinated functional groups can improve the lipophilicity, membrane permeability and antioxidant properties of the molecules, and can also improve the metabolic stability and efficacy of drug molecules. Benzoxazole derivatives are important pharmaceutical intermediates in business. As a heterocyclic compound, benzoxazole is used in research as a starting material for synthesizing larger, usually biologically active structures. Its aromaticity makes it relatively stable, although as a heterocycle, it has active sites that enable it to be functionalized. The above embodiments of the present invention achieve the synthesis of fluorinated benzoxazole compounds. The synthetic reaction activity of the fluorinated benzoxazole compounds in the above embodiments of the present invention is high, the substrate is cheap and easy to obtain, and the cost is low; the method of the above embodiments of the present invention has the characteristics of simple operation, mild conditions, excellent functional group compatibility, and high yield.

[0129] The embodiments of the present invention are described above, but the present invention is not limited to the above embodiments. Various changes can be made according to the purpose of the invention. Any changes, modifications, substitutions, combinations or simplifications made according to the spirit and principle of the technical solution of the present invention should be equivalent replacement methods. As long as they meet the purpose of the invention and do not deviate from the technical principles and inventive concepts of the present invention, they belong to the protection scope of the present invention.

Claims

1. A method for preparing a fluorinated benzoxazole compound, characterized in that: A fluorinated heterocyclic building block substituted with monobromodifluoromethyl and methyl acrylate are reacted under photocatalytic conditions, and a photosensitizer, a hydrogen source, a base and a solvent are added to synthesize a fluorinated benzoxazole compound in one step; the steps of the preparation method are as follows: (1) Preparation of reactant mixed solution system: Adding a fluorinated heterocyclic building block substituted with monobromodifluoromethyl, methyl acrylate, a photosensitizer, a hydrogen source and a base into a reaction tube, adding a solvent into the reaction tube, protecting with nitrogen, and tightening the piston of the reaction tube to obtain a reactant mixed solution system; The structure of the fluorinated heterocyclic building block substituted with monobromodifluoromethyl is: Wherein, R is -H, -CH3, -C(CH3)3, -Cl or -Br; The photosensitizer and hydrogen source are 2,6-dimethyl-1,4-dihydro-3,5-pyridinedicarboxylic acid diethyl ester; The base is triethylamine; (2) Preparation of fluorinated benzoxazole compounds: At room temperature, the reactant mixed solution system is irradiated with a blue LED lamp for 12 to 36 hours. After the reaction is completed, the solvent is removed, and the mixture is extracted with ethyl acetate and saturated brine. The organic phase is concentrated under reduced pressure, and the crude product is purified by column chromatography to obtain a fluorinated benzoxazole compound. The structure of the fluorinated benzoxazole compound is:

2. The method for preparing a fluorinated benzoxazole compound according to claim 1, characterized in that: In the step (1), the solvent is at least one of 1,4-dioxane, acetonitrile, acetone, tetrahydrofuran, dimethyl sulfoxide, 1,2-dichloroethane and isopropanol.

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