Preparation method of adamantyl triphenylamine

Abstract

The invention discloses a preparation method of adamantyl triphenylamine, which comprises the following steps: 1, reacting o-aminobiphenyl with N-bromosuccinimide and an organic solvent to prepare an intermediate I; 2, adding 1-adamantanol and chlorobenzene into an organic solvent, and reacting under the action of strong acid to prepare an intermediate II; 3, adding the intermediate II, alkali and bis (pinacolato) diboron into an organic solvent, and reacting under the action of a palladium catalyst to prepare an intermediate III; and step 4, adding the intermediate III, the intermediate I, a palladium catalyst, alkali salt and tetrabutylammonium bromide into a mixed solution of toluene and deionized water, and carrying out Suzuki reaction to obtain adamantyl triphenylamine. The preparation method of adamantyl triphenylamine has the advantages of easily available raw materials, simple operation, high reaction yield in each step, high purity of the obtained product, and realization of industrialization.

Description

Technical Field

[0001] The invention belongs to the technical field of organic synthesis, in particular to a method for preparing adamantyl triphenylamine. Background Art

[0002] Organic electroluminescence (OLED) refers to the phenomenon in which organic materials emit fluorescence when stimulated by an electric current or electric field. Devices made with small organic molecules as luminescent materials are called organic electroluminescent devices (OLEDs). Materials used in OLEDs can be broadly categorized as hole transport materials, electron transport materials, and luminescent materials. Among the many organic optoelectronic materials, adamantyl triphenylamine derivatives are widely used as hole transport materials due to their electron-rich structure, wide band gap, high fluorescence quantum yield, and the formation of unique cation radicals under the influence of an electric field. In recent years, with the rapid development of this class of organic compound materials and the market's active pursuit of domestic production, the industrial production of adamantyl triphenylamine-based organic intermediates has become increasingly urgent. Therefore, continuous research and innovation are necessary to design an environmentally friendly synthesis process for adamantyl triphenylamine that is suitable for industrial production, economically viable, and in line with market demand.

[0003] At present, there are few reports on the synthesis method of this compound, and the yield is low. For example, in patent document CN202111611923.7, adamantane phenyl trifluoromethanesulfonate and 4-amino-3-phenylboron ester are prepared by Suzuki reaction under the catalysis of tetrakistriphenylphosphine palladium, and the yield is only 19.56%. Under the condition of changing the catalyst Pd(PPh3)2Cl2, the yield is only increased to 74.68%. Therefore, it is crucial to design and develop a method that is both economical and suitable for industrial production of adamantyl triphenylamine.

[0004] Based on the above problems, the present invention provides a method for preparing adamantyl triphenylamine, which can solve the problems of low yield and poor economic applicability of the preparation of adamantyl triphenylamine in the prior art. Summary of the Invention

[0005] The purpose of the invention is to provide a method for preparing adamantyl triphenylamine to solve the problems of low yield and poor economic applicability of the prior art preparation of adamantyl triphenylamine.

[0006] Technical solution:

[0007] A method for preparing adamantyl triphenylamine, comprising the steps of: Step 1: Take o-aminobiphenyl, N-bromosuccinimide and an organic solvent to react to obtain intermediate I ; Step 2: Add 1-adamantanol and chlorobenzene to an organic solvent and react under the action of a strong acid to obtain intermediate II. ; Step 3: Add intermediate II, alkali salt and biboronic acid pinacol ester to an organic solvent and react under the action of palladium catalyst to obtain intermediate III. ; Step 4: Add intermediate III, intermediate I, palladium catalyst, alkali salt and tetrabutylammonium bromide to a mixed solution of toluene and deionized water to carry out Suzuki reaction to obtain adamantyl triphenylamine .

[0008] In a further embodiment, in step 1, the organic solvent is dichloromethane or tetrahydrofuran.

[0009] In a further embodiment, in step 2, the organic solvent is dichloromethane.

[0010] In a further embodiment, in step 2, the strong acid is concentrated sulfuric acid.

[0011] In a further embodiment, in step three, the alkali salt is potassium acetate.

[0012] In a further embodiment, in step three, the organic solvent is 1,4-dioxane.

[0013] In a further embodiment, in step three, the palladium catalyst is 1,1'-bis(diphenylphosphino)ferrocenepalladium dichloride.

[0014] In a further embodiment, in step 4, the alkali salt is potassium carbonate or sodium carbonate.

[0015] In a further embodiment, in step 4, the palladium catalyst is tetrakistriphenylphosphine palladium.

[0016] In a further embodiment, in step 4, the volume ratio of toluene to deionized water is 3:1.

[0017] Beneficial effects of the present invention: (1) The raw materials of the present invention are easily available, the operation is simple, the three wastes are less, and industrial production has been realized.

[0018] (2) Compared with the reported methods, the present invention has a shorter route, higher yield and lower cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a flow chart of the method of the present invention.

[0020] Figure 2 The figure is the hydrogen nuclear magnetic spectrum of 4-(1-adamantan-1-yl)[terphenyl]-4-amine of the present invention.

[0021] Figure 3 It is the H NMR spectrum of intermediate II of the present invention.

[0022] Figure 4 It is the nuclear magnetic hydrogen spectrum of intermediate III of the present invention. DETAILED DESCRIPTION

[0023] In the following description, numerous specific details are provided to provide a more thorough understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced without one or more of these details. In other instances, certain technical features well known in the art are not described to avoid confusion with the present invention.

[0024] The present invention will be further described in detail below with reference to the accompanying drawings.

[0025] Reference Figure 1-4 , is a preparation method of adamantyl triphenylamine disclosed in the present invention, and the specific implementation route of the present invention is as follows:

[0026] The method comprises the following steps: Step 1: reacting o-aminobiphenyl with N-bromosuccinimide and an organic solvent to obtain intermediate I, wherein the organic solvent is dichloromethane or tetrahydrofuran; Step 2: 1-adamantanol and chlorobenzene are added to an organic solvent and reacted in the presence of a strong acid to obtain Intermediate II, wherein the organic solvent is dichloromethane and the strong acid is concentrated sulfuric acid; Step 3: adding intermediate II, an alkali salt and bipyralidoboric acid pinacol ester to an organic solvent and reacting in the presence of a palladium catalyst to obtain intermediate III, wherein the alkali salt is potassium acetate, the organic solvent is 1,4-dioxane, and the palladium catalyst is 1,1'-bis(diphenylphosphino)ferrocenepalladium dichloride; Step 4: Add intermediate III, intermediate I, a palladium catalyst, an alkali salt and tetrabutylammonium bromide to a mixed solution of toluene and deionized water for Suzuki reaction to obtain adamantyl triphenylamine, wherein the alkali salt is potassium carbonate or sodium carbonate, the palladium catalyst is tetrakistriphenylphosphine palladium, and the volume ratio of toluene and deionized water is 3:1.

[0027] Example 1: A method for synthesizing adamantyl triphenylamine, comprising the following steps: Step 1: Add 100 g (590.92 mmol) of 2-benzidine and 800 ml of dichloromethane to a three-necked flask, cool to 0°C, and add 105 g (590.92 mmol) of NBS in small batches. Control the temperature between 0°C ± 5°C during the addition process, then react for 1 hour. After the reaction is complete as monitored by liquid chromatography, stop the reaction, add 800 ml of pure water, separate the water, extract the aqueous phase once with 200 ml of dichloromethane, combine the organic phases, wash them again with water twice, concentrate at 60°C under normal pressure until no product is obtained, crystallize the product with 200 ml of petroleum ether at room temperature for 6 hours, directly filter, and dry to obtain 139.24 g of 5-bromo-[1,1'-biphenyl]-2-amine as an off-white solid powder (Intermediate I), HPLC = 99.53%, yield 94.97%; Step 2: Add 100 g (656.87 mmol) of 1-adamantanol, 86.67 g (788.24 mmol) of chlorobenzene, and 1.2 L of dichloromethane to a 2 L three-necked flask, stir and dissolve at room temperature until it becomes clear and transparent, slowly add 130 g (1313.74 mmol) of concentrated sulfuric acid dropwise at room temperature for 1 hour, heat to 40-45 ° C and react for 3 hours. After the reaction is complete by liquid phase monitoring, stop the reaction, wash the system with water, extract with dichloromethane, wash the organic phase with water, concentrate at normal pressure, recrystallize from toluene, disperse in petroleum ether, and dry to obtain 123.11 g of the product 1-(4-chlorophenyl)adamantane as a white solid powder (Intermediate II), HPLC = 99.25%, yield 75.95%; the H NMR spectrum of the obtained Intermediate II is shown in Figure 3 .

[0028] Step 3: Add 103 g (405.61 mmol) of 1-(4-chlorophenyl)adamantane, 79.48 g (811.22 mmol) of potassium acetate, 123.48 g (486.73 mmol) of biboronic acid pinacol ester, and 800 mL of water into a three-necked flask. 1,4-dioxane was stirred and heated to 55-60°C under nitrogen protection, 1.48 g (2.03 mmol) of 1,1'-bis(diphenylphosphino)ferrocenepalladium dichloride as a catalyst was added, and the temperature was raised to 90-95°C for 3 h. The reaction was stopped after completion of the reaction by liquid phase monitoring. After post-treatment, water was added for washing, toluene was extracted, the organic phase was washed with water, the organic phase was passed through a column, the column liquid was concentrated, petroleum ether was dispersed for crystallization, filtered, and dried at 50°C to obtain 123.37 g of 4-(1-adamantyl)phenylboronic acid pinacol ester as a white solid powder (intermediate III), HPLC = 99.75%, yield 87.38%; the H NMR spectrum of the obtained intermediate III is shown in Figure 4 .

[0029] Step 4: Add 123.37 g (364.68 mmol) of 4-(1-adamantyl)phenylboronic acid pinacol ester, 90.51 g (364.68 mmol) of 5-bromo-[1,1'-biphenyl]-2-amine, 125.81 g (911.70 mmol) of potassium carbonate, 11.75 g (36.46 mmol) of TBAB, 690 ml of toluene, and 230 ml of water to a three-necked flask, and heat to 45-50 ° C. Add 1.26 g (1.09 mmol) of tetrakistriphenylphosphine palladium as catalyst, and continue to heat to 60-73 ° C. and react for 9 hours. The reaction is stopped after the reaction is complete by liquid phase monitoring. After post-treatment, water is added for washing, the aqueous phase is extracted with toluene, the organic phase is dried over anhydrous sodium sulfate and then passed through a silica gel column. After concentration, it is recrystallized from toluene, filtered, and dried to obtain 126.42 g of the product adamantyl triphenylamine as a white solid, HPLC = 99.61%, and the yield is 91.34 %; The H NMR spectrum of the obtained 4-(1-adamantan-1-yl)[terphenyl]-4-amine is shown in Figure 2 .

[0030] Example 2:

[0031] A method for synthesizing adamantyl triphenylamine, comprising the following steps: Step 1: Add 100 g (590.92 mmol) of 2-benzidine and 800 ml of tetrahydrofuran to a three-necked flask, cool to 0°C, and add 105 g (590.92 mmol) of NBS in small batches. Control the temperature between -5°C ± 5°C during the addition process, then react for 1 hour. After the reaction is complete as monitored by liquid chromatography, stop the reaction, add 800 ml of pure water, extract the aqueous phase twice with 1 L of dichloromethane, combine the organic phases, wash them again with water twice, and concentrate at 60°C under normal pressure until no product is obtained. Crystallize the product at room temperature for 6 hours with 200 ml of petroleum ether, filter directly, and dry to obtain 135.21 g of 5-bromo-[1,1'-biphenyl]-2-amine as an off-white solid powder (Intermediate I). HPLC = 99.61%, yield 92.22%; Step 2: Add 100 g (656.87 mmol) of 1-adamantanol, 86.67 g (788.24 mmol) of chlorobenzene, and 1.2 L of dichloromethane to a 2 L three-necked flask. Stir and dissolve at room temperature until the solution becomes clear and transparent. Slowly add 130 g (1313.74 mmol) of concentrated sulfuric acid dropwise at room temperature over 1 hour. Heat to 40-45 ° C and react for 3 hours. Monitor the reaction by liquid chromatography and stop the reaction after the reaction is complete. Wash the system with water, extract with dichloromethane, wash the organic phase, concentrate at normal pressure, recrystallize from toluene, disperse in petroleum ether, and dry to obtain 110.02 g of 1-(4-chlorophenyl)adamantane as a white solid powder (Intermediate II). HPLC = 99.14%, yield 67.88%.

[0032] Step 3: Add 110 g (445.74 mmol) of 1-(4-chlorophenyl)adamantane, 87.48 g (891.48 mmol) of potassium acetate, 135.82 g (534.88 mmol) of biboronic acid pinacol ester, and 800 mL of water into a three-necked flask. 1,4-dioxane was stirred and heated to 55-60°C under nitrogen protection. 1.63 g (2.22 mmol) of 1,1'-bis(diphenylphosphino)ferrocenepalladium dichloride was added as a catalyst. The temperature was raised to 90-95°C and the reaction was maintained for 3 h. The reaction was stopped after completion of the reaction as monitored by liquid phase chromatography. The reaction was washed with water and extracted with toluene. The organic phase was washed with water and passed through a column. The column liquid was concentrated, dispersed with petroleum ether for crystallization, filtered, and dried at 50°C to obtain 135.71 g of 4-(1-adamantyl)phenylboronic acid pinacol ester as a white solid powder (Intermediate III). HPLC = 99.75%, yield 89.99%.

[0033] Step 4: Add 135.71 g (401.15 mmol) of 4-(1-adamantyl)phenylboronic acid pinacol ester, 99.53 g (401.15 mmol) of 5-bromo-[1,1'-biphenyl]-2-amine, 106.29 g (1002.87 mmol) of sodium carbonate, and TBAB into a three-necked flask. 11.75 g (36.46 mmol), 690 ml of toluene, and 230 ml of water were heated to 45-50°C, and 1.39 g (1.20 mmol) of tetrakistriphenylphosphine palladium catalyst was added. The temperature was continued to rise to 60-73°C for 9 h. The reaction was stopped after completion of the reaction as monitored by liquid chromatography. After post-treatment, the product was washed with water, and the aqueous phase was extracted with toluene. The organic phase was dried over anhydrous sodium sulfate and passed through a silica gel column. After concentration, it was recrystallized from toluene, filtered, and dried to obtain 137.13 g of the product, adamantyl triphenylamine, as a white solid. HPLC = 99.72%, yield 87.76%.

[0034] Comparative Example 1: The concentrated sulfuric acid in step 2 of Example 1 was replaced by trifluoromethanesulfonic acid, and the other steps were the same, as follows: To a 2 L three-necked flask, 100 g (656.87 mmol) of 1-adamantanol, 86.67 g (788.24 mmol) of chlorobenzene, and 1.2 L of dichloromethane were added. The mixture was stirred and dissolved at room temperature until it became clear and transparent. 98.53 g (1313.74 mmol) of trifluoromethanesulfonic acid was slowly added dropwise at room temperature over 1 h. The temperature was raised to 40-45°C and the reaction was completed for 3 h. The reaction was stopped after completion of the reaction as monitored by liquid chromatography. The system was washed with water, extracted with dichloromethane, and the washed organic phase was concentrated under normal pressure. The mixture was passed through a silica gel column with toluene, concentrated under reduced pressure, dispersed with petroleum ether, and dried to obtain 78 g of 1-(4-chlorophenyl)adamantane as a white solid powder (Intermediate II) with an HPLC index of 98.53% and a yield of 48.12%.

[0035] Comparative Example 2: The catalyst tetrakistriphenylphosphine palladium in step 4 of Example 1 was replaced with bistriphenylphosphine palladium dichloride, and the other steps were the same, as follows: In a 2L three-necked flask, 123.37 g (364.68 mmol) of 4-(1-adamantyl)phenylboronic acid pinacol ester, 90.51 g (364.68 mmol) of 5-bromo-[1,1'-biphenyl]-2-amine, 125.81 g (911.70 mmol) of potassium carbonate, and TBAB were added. The reaction mixture was stirred for 1 h. The reaction mixture was stirred for 2 h. 11.75 g (36.46 mmol) of bis(triphenylphosphine)palladium(II) chloride (PTP-PA-2) was added to 690 ml of toluene and 230 ml of water. The temperature was raised to 45-50 °C, and 1.26 g (1.09 mmol) of bis(triphenylphosphine)palladium(II) chloride (PTP-PA-2) was added as a catalyst. The temperature was continued to rise to 60-73 °C for 9 h. Liquid phase monitoring showed that 32.1% of the starting material remained. The reaction time was then extended to 16 h. Liquid phase monitoring showed that 11.3% of the starting material remained. The product was washed with water, extracted with toluene, and the organic phase was dried over anhydrous sodium sulfate and passed through a silica gel column. After concentration, the product was recrystallized with toluene, filtered, and dried to obtain 101.42 g of adamantyl triphenylamine as a white solid. HPLC analysis indicated a yield of 73.28%.

[0036] Comparative Example 3: The equivalent of the catalyst tetrakistriphenylphosphine palladium in step 4 of Example 1 was reduced to 0.001 equivalents, and the other steps were the same, as follows: In a 2L three-necked flask, 123.37 g (364.68 mmol) of 4-(1-adamantyl)phenylboronic acid pinacol ester, 90.51 g (364.68 mmol) of 5-bromo-[1,1'-biphenyl]-2-amine, 125.81 g (911.70 mmol) of potassium carbonate, 11.75 g (36.46 mmol) of TBAB, 690 ml of toluene, and 230 ml of water were added. The temperature was raised to 45-50°C, and 419 mg (0.365 mmol) of tetrakistriphenylphosphine palladium was added as a catalyst. The temperature was continued to rise to 60-73°C and the reaction was allowed to proceed for 9 h. After post-treatment, the mixture was washed with water, and the aqueous phase was extracted with toluene. The organic phase was dried over anhydrous sodium sulfate and passed through a silica gel column. After concentration, the mixture was recrystallized from toluene, filtered, and dried to obtain 89.17 g of adamantyl triphenylamine as a white solid with an HPLC index of 99.33% and a yield of 64.42%.

[0037] Comparative Example 4: The solvent toluene in step 4 of Example 1 was replaced with tetrahydrofuran, and the other steps were the same, as follows: To a 2L three-necked flask were added 123.37 g (364.68 mmol) of 4-(1-adamantyl)phenylboronic acid pinacol ester, 90.51 g (364.68 mmol) of 5-bromo-[1,1'-biphenyl]-2-amine, 125.81 g (911.70 mmol) of potassium carbonate, 11.75 g (36.46 mmol) of TBAB, 690 ml of tetrahydrofuran, and 230 ml of water. The temperature was raised to 45-50°C, and 419 mg (0.365 mmol) of tetrakistriphenylphosphine palladium was added as a catalyst. The temperature was continued to rise to 60-73°C and the reaction was allowed to proceed for 9 h. After post-treatment, the mixture was washed with water, and the aqueous phase was extracted with toluene. The organic phase was dried over anhydrous sodium sulfate and passed through a silica gel column. After concentration, the mixture was recrystallized from toluene, filtered, and dried to obtain 84.68 g of adamantyl triphenylamine as a white solid with an HPLC index of 99.33% and a yield of 61.17%.

[0038] The reaction conditions and yields of Example 1 and Comparative Examples 2-4 are shown below:

[0039] As can be seen from the above table, compared with Example 1, Comparative Example 2 changed the type of catalyst and the yield was 73.28%; compared with Example 1, Comparative Example 3 reduced the proportion of the catalyst and the yield was reduced by 26.92%; compared with Example 1, Comparative Example 4 changed the solvent and the yield was only 61.17%.

[0040] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

[0041] The preferred embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, various equivalent transformations can be made to the technical solutions of the present invention, and these equivalent transformations all fall within the scope of protection of the present invention.

Claims

1. A method for preparing adamantyl triphenylamine, characterized in that: The method comprises the following steps: Step 1: Take o-aminobiphenyl, N-bromosuccinimide and an organic solvent to react to obtain intermediate I ； Step 2: Add 1-adamantanol and chlorobenzene to an organic solvent and react under the action of a strong acid to obtain intermediate II. ； Step 3: Add intermediate II, alkali salt and biboronic acid pinacol ester to an organic solvent and react under the action of palladium catalyst to obtain intermediate III. ； Step 4: Add intermediate III, intermediate I, palladium catalyst, alkali salt and tetrabutylammonium bromide to a mixed solution of toluene and deionized water to carry out Suzuki reaction to obtain adamantyl triphenylamine 。 2. The method for preparing adamantyl triphenylamine according to claim 1, wherein: In the step 1, the organic solvent is dichloromethane or tetrahydrofuran.

3. The method for preparing adamantyl triphenylamine according to claim 1, wherein: In the step 2, the organic solvent is dichloromethane.

4. The method for preparing adamantyl triphenylamine according to claim 1, wherein: In the step 2, the strong acid is concentrated sulfuric acid.

5. The method for preparing adamantyl triphenylamine according to claim 1, wherein: In the step 3, the alkali salt is potassium acetate.

6. The method for preparing adamantyl triphenylamine according to claim 1, wherein: In the step 3, the organic solvent is 1,4-dioxane.

7. The method for preparing adamantyl triphenylamine according to claim 1, wherein: In the step 3, the palladium catalyst is 1,1'-bis(diphenylphosphinoferrocene)palladium dichloride.

8. The method for preparing adamantyl triphenylamine according to claim 1, wherein: In the step 4, the alkali salt is potassium carbonate or sodium carbonate.

9. The method for preparing adamantyl triphenylamine according to claim 1, wherein: In the step 4, the palladium catalyst is tetrakistriphenylphosphine palladium.

10. The method for preparing adamantyl triphenylamine according to claim 1, wherein: In the step 4, the volume ratio of toluene to deionized water is 3:1.

Images