Process for the preparation of a boron-nitrogen naphthalene derivative and its use

Abstract

The application discloses a method for preparing a boron-nitrogen naphthalene derivative, and comprises the following steps: under the protection of argon, a certain amount of 1,2-dihydroboron-nitrogen naphthalene, acetylacetone cobalt (II), 4,5-bis-diphenylphosphine-9,9-dimethyl xanthene, phenylacetylene and a solvent are reacted under certain temperature conditions; after the reaction is completed, part of the solvent is removed under reduced pressure, the reaction is quenched, extraction, drying and column chromatography purification are performed to obtain a pure boron-nitrogen naphthalene derivative. The technical scheme has the characteristics of simple preparation method, easy-to-obtain raw materials, mild reaction conditions, no need to use noble metal reagents and simple operation steps. The boron-nitrogen naphthalene derivative prepared by the application can effectively absorb ultraviolet light with a wavelength range of 200-350 nm. The compound can be used as an ultraviolet absorber, and is expected to improve the light stability of high polymer materials.

Description

Technical Field

[0001] This invention relates to the field of organic ultraviolet absorbers, and particularly to a method for preparing a borazanine derivative that can be used for organic ultraviolet absorption. Background Technology

[0002] Ultraviolet (UV) radiation breaks down polymer molecular chains, leading to photodegradation. It also generates free radicals, causing photo-oxidation. UVB (medium-wave UV) radiation is particularly potent, easily causing polymer cracking and discoloration. UVA (long-wave UV) radiation has strong penetrating power, easily causing internal degradation. Therefore, developing UV absorbers with absorption wavelengths covering both UVB and UVA is crucial for extending the lifespan of polymer products. Due to boron's unique electronic structure, organoboron compounds possess unique advantages such as wide absorption bands, excellent thermal stability, and functional versatility, attracting interest in the synthesis and application of organoboron UV absorbers. Currently, high-performance organoboron UV absorbers are relatively rare in the field of UVB and UVA protection.

[0003] Current literature reports on the preparation methods of 2-styryl-1,2-dihydroborazonaphthalene (ACS Catal. 2024, 14, 16996−17003) mainly involve using 1,2-dihydroborazonaphthalene and haloolefins as raw materials, and obtaining the target product under the action of a noble metal palladium catalyst.

[0004]

[0005] This preparation method requires the use of expensive palladium catalysts, the starting material haloolefins are not readily available, the atom economy of the reaction is not high, and the yield is only 26%.

[0006] It is urgent to develop a method for preparing 2-styrene-1,2-dihydroborazonaphthalene that is atom-economical and yield-efficient, starting from readily available raw materials and avoiding the use of precious metal reagents. Summary of the Invention

[0007] To address the aforementioned problems, this invention provides a borazanine derivative and its preparation method that are simple to prepare, use readily available raw materials, do not require precious metal reagents, have mild reaction conditions, high atom economy, and concise operation steps.

[0008] This invention patent discloses a method for preparing borazonaphthalene derivatives, specifically including the following steps: Step 1) Under argon protection, a certain amount of 1,2-dihydroborazonaphthalene, cobalt(II) acetylacetonate, 4,5-bisdiphenylphosphine-9,9-dimethyloxanethium, phenylacetylene and solvent are reacted under certain temperature conditions;

[0009] Step 2) After the reaction is complete, some solvent is removed under reduced pressure, the reaction is quenched with saturated sodium bicarbonate solution, extracted with dichloromethane, dried over anhydrous sodium sulfate, and purified by column chromatography to obtain the pure borazanine derivative; wherein the structural formula of the borazanine derivative is as follows: .

[0010] The above-mentioned borazanine derivatives were prepared in anhydrous ethanol to form 10 -5 The solution, at room temperature, exhibits good UV absorption properties when tested for UV absorption at a concentration of mol / L.

[0011] Preferably, the solvent is tetrahydrofuran, dichloromethane, or 1,2-dichloroethane.

[0012] Preferably, the reaction temperature is 20-80°C. o C.

[0013] Preferably, the molar ratio of 1,2-dihydroborazonaphthalene, cobalt(II) acetylacetonate, 4,5-bis(diphenylphosphine)-9,9-dimethyloxanethium and phenylacetylene is 1:0.01-0.1:0.01-0.1:0.5-1.

[0014] Preferably, the feeding ratio of 1,2-dihydroborazonaphthalene to solvent is 1 mmol: 5-10 mL.

[0015] This invention patent also discloses the application of the prepared borazanine derivative, which is used as a UV absorber.

[0016] The above technical solution has the following beneficial effects: the preparation method of the borazine derivative does not require the use of precious metal reagents, the raw materials are easy to obtain, the reaction has high chemical selectivity, the post-processing is convenient, the reaction conditions in the preparation process are mild, the synthesis steps are simple, and the yield can reach more than 50%; the borazine derivative synthesized by the present invention has a wide absorption band and good ultraviolet absorption performance. Attached Figure Description

[0017] Figure 1 The target compound of the present invention 1 H NMR spectrum.

[0018] Figure 2 The target compound of the present invention 13 C10 NMR spectrum.

[0019] Figure 3 This is the ultraviolet-visible absorption spectrum of the target compound in an embodiment of the present invention. Detailed Implementation

[0020] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0021] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided to make the invention more comprehensive and complete, and to fully convey the concept of the exemplary embodiments to those skilled in the art. The described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a full understanding of embodiments of the invention. However, those skilled in the art will recognize that the technical solutions of the invention may be practiced with one or more of these specific details omitted, or other methods, components, apparatus, steps, etc., may be employed. In other instances, well-known technical solutions are not shown or described in detail to avoid obscuring various aspects of the invention.

[0022] The present invention will be further described in detail below with reference to the embodiments.

[0023] Example 1: A method for preparing 2-styryl-1,2-dihydroborazonaphthalene.

[0024] Step 1) In a 10 mL reactor, under argon protection, add 1,2-dihydroborazonaphthalene (0.20 mmol), cobalt(II) acetylacetonate (0.01 mmol), 4,5-bisdiphenylphosphine-9,9-dimethyloxanthracene (0.012 mmol), phenylacetylene (0.10 mmol), and tetrahydrofuran (1 mL), and react at 50°C for 12 hours;

[0025] Step 2) After the reaction was completed, some solvent was removed under reduced pressure, the reaction was quenched with saturated sodium bicarbonate solution, extracted with dichloromethane, dried over anhydrous sodium sulfate, and purified by column chromatography to obtain pure 2-styryl-1,2-dihydroborazonaphthalene, with the following structural formula:

[0026]

[0027] Yield: 58%; white solid; as Figures 1 to 2As shown, its 1H NMR spectrum (Chloroform-d, 400 MHz) is as follows: δ 8.06 (d, J = 11.6 Hz, 1H), 7.86 (s, 1H), 7.61 (t, J = 8.4 Hz, 3H), 7.52 (d, J = 18.0 Hz, 1H), 7.46 – 7.36 (m, 3H), 7.35 – 7.24 (m, 2H), 7.17 (t, J = 6.4 Hz, 2H), 6.83 (d, J = 18.0 Hz, 1H). Carbon NMR spectrum (Chloroform-d, 101 MHz): δ 145.5, 144.8, 140.3, 138.4, 129.5, 128.7, 128.4, 128.3, 126.9, 125.9, 121.0, 118.1. High-resolution mass spectrometry (ESI) calcd for C16H14BN [M+H]+ 232.1292, found 232.1280.

[0028] Example 2: A method for preparing 2-styryl-1,2-dihydroborazonaphthalene.

[0029] Step 1) In a 10 mL reactor, 1,2-dihydroborazonaphthalene (0.20 mmol), cobalt(II) acetylacetonate (0.01 mmol), 4,5-bisdiphenylphosphine-9,9-dimethyloxanthracene (0.012 mmol), phenylacetylene (0.10 mmol), and dichloromethane (1 mL) were added under argon protection. The reaction was carried out at 50°C for 12 hours.

[0030] Step 2) After the reaction was completed, some of the solvent was removed under reduced pressure, the reaction was quenched with saturated sodium bicarbonate solution, extracted with dichloromethane, dried with anhydrous sodium sulfate, and purified by column chromatography to obtain pure 2-styryl-1,2-dihydroborazonaphthalene with a yield of 74%.

[0031] Example 3: A method for preparing 2-styryl-1,2-dihydroborazonaphthalene.

[0032] Step 1) In a 10 mL reactor, under argon protection, add 1,2-dihydroborazanaphthalene (0.20 mmol), cobalt(II) acetylacetonate (0.01 mmol), 4,5-bis(diphenylphosphine)-9,9-dimethyloxanthracene (0.012 mmol), phenylacetylene (0.10 mmol), and 1,2-dichloroethane (1 mL), and react at 50°C for 12 hours;

[0033] Step 2) After the reaction was completed, some of the solvent was removed under reduced pressure, the reaction was quenched with saturated sodium bicarbonate solution, extracted with dichloromethane, dried with anhydrous sodium sulfate, and purified by column chromatography to obtain pure 2-styryl-1,2-dihydroborazonaphthalene with a yield of 87%.

[0034] The preparation method of this borazanine derivative does not require the use of precious metal reagents, the raw materials are readily available, the reaction has high chemical selectivity, the post-processing is convenient, the reaction conditions are mild, the synthesis steps are simple, and the yield can reach more than 50%. The synthesized borazanine derivative has a wide absorption band and good ultraviolet absorption performance.

[0035] like Figure 3 As shown, as a specific experimental example, the UV-Vis absorption spectrum of 2-styryl-1,2-dihydroborazonaphthalene prepared in Example 1 was tested at room temperature at a concentration of 10⁻⁵ mol / L. This 2-styryl-1,2-dihydroborazonaphthalene exhibits strong UV absorption in the 200-350 nm range.

[0036] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A method for preparing a borazanine derivative, characterized in that, It includes the following steps: Step 1) Under argon protection, a certain amount of 1,2-dihydroborazonaphthalene, cobalt(II) acetylacetonate, 4,5-bisdiphenylphosphine-9,9-dimethyloxanthracene, phenylacetylene and solvent are reacted under certain temperature conditions. Step 2) After the reaction is complete, some solvent is removed under reduced pressure, the reaction is quenched with saturated sodium bicarbonate solution, extracted with dichloromethane, dried over anhydrous sodium sulfate, and purified by column chromatography to obtain the pure borazanine derivative; wherein the structural formula of the borazanine derivative is as follows: .

2. The method for preparing the borazanine derivative according to claim 1, characterized in that: The solvents are tetrahydrofuran, dichloromethane, and 1,2-dichloroethane.

3. The method for preparing the borazanine derivative according to claim 1, characterized in that: The reaction temperature is 20-80°C. o C.

4. The method for preparing the borazanine derivative according to claim 1, characterized in that: The molar ratio of 1,2-dihydroborazonaphthalene, cobalt(II) acetylacetonate, 4,5-bisdiphenylphosphine-9,9-dimethyloxanethium and phenylacetylene is 1:0.01-0.1:0.01-0.1:0.5-1.

5. The method for preparing the borazanine derivative according to claim 1, characterized in that: The feeding ratio of 1,2-dihydroborazonaphthalene to solvent is 1 mmol: 5-10 mL.

6. An application of the borazanine derivative according to claim 1, characterized in that: It is used to prepare ultraviolet absorbers from high molecular weight polymers.

Images