Organic photocatalytic material and preparation method thereof

Abstract

The application relates to the technical field of catalytic materials, and relates to an organic photocatalytic material and a preparation method thereof.1, comprising the following steps: mixing modified N-hydroxy phthalimide phenylacetate, an aliphatic nitroalkane, 2,6-dimethylpyridine, a photocatalyst and a solvent, then irradiating under visible light, placing in an inert atmosphere, stirring for 2-8 hours, and obtaining a product through post-treatment to obtain a final product; the mass ratio of the modified N-hydroxy phthalimide phenylacetate, the nitro compound, the 2,6-dimethylpyridine, the photocatalyst and the solvent is 2-5:1-2:1-3:1:8-11. The visible light catalysis method can be used to synthesize the nitro compound under mild conditions, and further provides a green and efficient new path for the preparation of a nitrogen-containing drug intermediate.

Description

Technical Field

[0001] This invention relates to the field of catalytic materials technology, and more specifically, to an organic photocatalytic material and its preparation method. Background Technology

[0002] In recent years, research in the field of photocatalysis has entered a period of rapid development. This technology, with its inherent green attributes and sustainable development potential, has become a crucial technological support for green chemistry and the promotion of sustainable development. Among these technologies, visible light photocatalysis stands out due to its unique advantages. Visible light is widely available on the Earth's surface, abundant, and inexpensive. Utilizing visible light to drive chemical reactions avoids the harsh reaction conditions of traditional high temperatures and pressures, reducing energy consumption and environmental pollution, aligning with the current trend of green chemistry development. Organic synthesis strategies based on visible light photocatalysis exhibit outstanding performance characteristics such as cleanliness, rapid reaction rates, mild and easy operation, and good selectivity, gradually becoming a popular research direction in organic chemistry. Research teams have continuously exerted their efforts in this field, achieving a series of influential research advances.

[0003] Nitro compounds can be considered as derivatives formed by replacing one or more hydrogen atoms in a hydrocarbon molecule with a nitro group (-NO2). Based on different hydroxyl groups, they can be classified into aliphatic nitro compounds (R-NO2) and aromatic nitro compounds (Ar-NO2). Nitro compounds are an important class of compounds in organic synthesis, widely found in pharmaceuticals, pesticides, materials, and other fields. Coupling reactions of nitro compounds are an effective method for constructing carbon-carbon and carbon-heteroatom bonds, playing a crucial role in organic synthesis. Through coupling reactions, simple nitro compounds can be transformed into structurally complex and functionally diverse organic molecules, greatly enriching the variety of organic compounds and providing strong technical support for innovative drug development and the preparation of high-performance materials.

[0004] In past research and practical applications of nitro compound coupling reactions, transition metal catalysts have frequently been used to promote the reactions. However, reactions using such catalysts require stringent reaction conditions. For example, transition metals palladium (Pd) and copper (Cu) have played a significant role in catalyzing nitro compound coupling reactions, driving the development of organic synthesis, but their catalytic processes still face significant thermodynamic challenges. In palladium-catalyzed systems, the reductive elimination step is difficult, requiring the crossing of extremely high reaction energy barriers; while in copper-catalyzed systems, the oxidative addition step also presents significant kinetic obstacles. Currently, to facilitate the reaction, high-temperature reaction environments or the design of special ligands are commonly employed. However, these strategies not only increase energy consumption and operational complexity but also limit the substrate versatility and practical application scope of the catalytic system. Summary of the Invention

[0005] This invention provides an organic photocatalytic material and its preparation method. The visible light photocatalysis method can synthesize nitro compounds under mild conditions, and further provides a green and efficient new route for the preparation of nitrogen-containing drug intermediates.

[0006] In a first aspect, the present invention provides a method for preparing an organic photocatalytic material, comprising the following steps: Modified N-hydroxyphthalimide phenylacetate, aliphatic nitroalkane, 2,6-dimethylpyridine, photocatalyst and solvent were mixed and reacted under visible light irradiation in an inert atmosphere for 2-8 hours with stirring. The product was obtained after post-treatment, and the final product was obtained.

[0007] Preferably, the mass ratio of the modified N-hydroxyphthalimide phenylacetate, aliphatic nitroalkane, 2,6-dimethylpyridine, photocatalyst, and solvent is 2~5:1~2:1~3:1:8~11.

[0008] Preferably, the modified N-hydroxyphthalimide phenylacetic acid ester is prepared from N-hydroxyphthalimide, 4-dimethylaminopyridine, dichloromethane, acetic acid and dicyclohexylcarbodiimide.

[0009] Preferably, the aliphatic nitroalkane is selected from one of nitroethane, nitromethane, nitropropane, and 2-nitropropane.

[0010] Preferably, the photocatalyst is selected from Ir(ppy)3 and / or eosin.

[0011] Preferably, the solvent is selected from at least one of ethyl acetate, acetonitrile, tetrahydrofuran, dichloromethane, methanol, ethanol, and toluene.

[0012] Preferably, the method for synthesizing the modified N-hydroxyphthalimide phenylacetic acid ester is as follows: N-hydroxyphthalimide, 4-dimethylaminopyridine, and dichloromethane are mixed, acetic acid is added, and then dicyclohexylcarbodiimide is added. The reaction system is placed at 25~35℃, stirred, and allowed to stand for 12~24h. After filtration, washing, concentration, and purification, the ester is obtained.

[0013] Preferably, the mass ratio of N-hydroxyphthalimide, 4-dimethylaminopyridine, dichloromethane, acetic acid and dicyclohexylcarbodiimide is 8~10:1~2:0.1~0.5:10~12:11~13.

[0014] Secondly, the present invention provides an organic photocatalytic material prepared by a method for preparing organic photocatalytic materials.

[0015] Preferably, the yield of the product is 60% to 85%.

[0016] Thirdly, this invention provides an application of an organic photocatalytic material in drug synthesis and material preparation.

[0017] In summary, the present invention has the following beneficial effects: 1. This invention utilizes visible light to catalyze the coupling reaction of nitro compounds, developing a green synthetic route using N-hydroxyphthalimide carboxylic acid ester as an intermediate. By systematically optimizing reaction conditions (base, solvent, photocatalyst) and substrate suitability, the invention overcomes the problems of harsh conditions, numerous side reactions, and narrow substrate range in traditional nitro compound alkylation reactions. Optimal reaction parameters were screened, and the triazabicyclo(4.4.0)dec-5-ene / acetone / Ir(ppy)3 combination was determined to be the best condition. Substrate selectivity was verified, revealing that straight-chain nitro compounds are more compatible with benzyl reactive esters, while sterically hindered substrates have limited reactivity. Finally, the product structure was confirmed using TLC and NMR.

[0018] 2. This invention, by exploring the reaction mechanism of visible light catalysis, can supplement the application of photocatalysis in the synthesis of nitrogen-containing compounds. It reveals the influence of substrate structure on free radical coupling reactions, realizes direct synthesis at room temperature without transition metals, reduces energy consumption and heavy metal pollution, and is suitable for the preparation of pharmaceutical intermediates, meeting the needs of green chemistry. Furthermore, it integrates the concepts of photochemistry, organic synthesis, and green chemistry, providing new ideas for traditional synthesis, promoting the development of the interdisciplinary field of "photocatalysis-drug synthesis," and helping the chemical industry transform towards low-carbon and high-efficiency production.

[0019] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit the scope of protection of the present invention. Attached Figure Description

[0020] Figure 1 It is the product 2-nitro-1-phenylpropane obtained by this invention. 1 H NMR spectrum and 13 C NMR spectrum; Figure 2 The products obtained in this invention are nitrobenzeneethane and (2-nitrobenzene). 1 H NMR spectrum; Figure 3 The product obtained in this invention is 1-methyl-4-(2-nitropropyl)benzene. 1 H NMR spectrum; Figure 4 The product obtained in this invention is 1-(2-methyl-2-nitropropyl)-3,5-bis(trifluoromethyl)benzene. 1 H NMR spectrum and 13 C NMR spectrum. Detailed Implementation

[0021] The present invention will be further described in detail below with reference to the embodiments. It should be noted that: unless otherwise specified, the conditions in the following embodiments are carried out according to conventional conditions or the conditions recommended by the manufacturer. Unless otherwise specified, the raw materials used in the following embodiments can be obtained from commercially available sources.

[0022] Example Synthesis of raw materials: The preparation of modified N-hydroxyphthalimide carboxylic acid ester is shown in the following method:

[0023] In a clean 250 mL round-bottom flask, N-hydroxyphthalimide (1.60 g, 10.0 mmol), DMAP (0.12 g, 1.0 mmol), and dichloromethane (0.1 M) were added sequentially, followed by carboxylic acid (10.0 mmol), and finally DCC (11.0 mmol). The reaction mixture was kept at room temperature and stirred overnight. During the reaction, the yellow suspension mostly turned into a white suspension. The reaction process was closely monitored using thin-layer chromatography (TLC). Once the test results indicated that the starting materials had completely reacted, the reaction mixture was transferred to a rotary evaporator to remove the solvent. The crude product was then purified by column chromatography to obtain the target product. If the product purity was found to be insufficient, dichloromethane and n-hexane could be used as a mixed solvent for recrystallization to further improve the product purity.

[0024] Under visible light catalysis, redox-active esters undergo single-electron reductive decarboxylation to generate corresponding alkyl radicals and nitro compounds, which then undergo a series of coupling reactions, as shown below:

[0025] The active ester used in this embodiment is N-hydroxyphthalimide phenylacetic acid ester, which is synthesized from N-hydroxyphthalimide and phenylacetic acid.

[0026] The reaction between modified N-hydroxyphthalimide phenylacetate and nitrobenzene is shown below:

[0027] Table 1: Final yields of products obtained in the examples and comparative examples

[0028] Table 2. Test results of corresponding active esters and products using TLC, IR, NMR, etc.

[0029] Tables 1 and 2 show that optimal reaction conditions and substrate applicability were obtained through raw material synthesis, condition screening, and substrate expansion experiments. During the condition screening process, it was found that higher yields were achieved when TBD was used as the base, Acetone as the solvent, and Ir(ppy)3 as the photocatalyst.

[0030] The above description is merely an exemplary embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for preparing an organic photocatalytic material, characterized in that, Includes the following steps: Modified N-hydroxyphthalimide phenylacetate, aliphatic nitroalkane, 2,6-dimethylpyridine, photocatalyst and solvent were mixed and reacted under visible light irradiation in an inert atmosphere for 2-8 hours with stirring. The product was obtained after post-treatment, and the final product was obtained.

2. The method for preparing the organic photocatalytic material according to claim 1, characterized in that, The mass ratio of the modified N-hydroxyphthalimide phenylacetate, aliphatic nitroalkane, 2,6-dimethylpyridine, photocatalyst, and solvent is 2~5:1~2:1~3:1:8~11.

3. The method for preparing the organic photocatalytic material according to claim 1, characterized in that, The modified N-hydroxyphthalimide phenylacetic acid ester is prepared from N-hydroxyphthalimide, 4-dimethylaminopyridine, dichloromethane, acetic acid and dicyclohexylcarbodiimide.

4. The method for preparing the organic photocatalytic material according to claim 1, characterized in that, The aliphatic nitroalkane is selected from one of nitroethane, nitromethane, nitropropane, and 2-nitropropane.

5. The method for preparing the organic photocatalytic material according to claim 1, characterized in that, The photocatalyst is selected from Ir(ppy)3 and / or eosin; The method for preparing the organic photocatalytic material according to claim 1 is characterized in that the solvent is selected from at least one of ethyl acetate, acetonitrile, tetrahydrofuran, dichloromethane, methanol, ethanol, and toluene.

6. The method for preparing the organic photocatalytic material according to claim 1, characterized in that, The modified N-hydroxyphthalimide phenylacetic acid ester is synthesized as follows: N-hydroxyphthalimide, 4-dimethylaminopyridine, and dichloromethane are mixed, acetic acid is added, and then dicyclohexylcarbodiimide is added. The reaction system is placed at 25~35℃, stirred, and allowed to stand for 12~24h. After filtration, washing, concentration, and purification, the ester is obtained.

7. The method for preparing the organic photocatalytic material according to claim 6, characterized in that, The mass ratio of N-hydroxyphthalimide, 4-dimethylaminopyridine, dichloromethane, acetic acid and dicyclohexylcarbodiimide is 8~10:1~2:0.1~0.5:10~12:11~13.

8. An organic photocatalytic material prepared by the method of any one of claims 1 to 7.

9. The organic photocatalytic material according to claim 8, characterized in that, The yield of the product is 60% to 85%.

10. The application of the organic photocatalytic material according to any one of claims 8 to 9, characterized in that, Applications in drug synthesis and materials preparation.

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