TW202300493A - Synthetic method of btbf aromatic amine derivatives - Google Patents

Abstract

The present invention provides a synthetic method of BTBF aromatic amine derivatives, which selects the commercialized raw materials in the market, and obtains the target product BTBF aromatic amine derivative through etherification, ring closure, bromination and coupling reaction. The synthetic method has the advantages of easy access to raw materials, short synthetic route, high yield, simple purification process, no need for column chromatography separation, and is suitable for large-scale production. The obtained product has high purity and few impurities, and is suitable for printing OLED devices.

Description

The synthetic method of BTBF aromatic amine derivative

The invention relates to the technical field of OLED material preparation, in particular to a method for synthesizing BTBF aromatic amine derivatives.

As an organic electroluminescent device of a new generation of display technology, OLED has a wide range of application prospects in display and lighting technology due to its own self-luminescence, high contrast, wide color gamut, large viewing angle, and fast response speed.

OLED display technology mainly has two distinct manufacturing processes. One is the evaporation process, which uses small molecule OLED light-emitting materials to form films by vacuum evaporation. The current process is relatively mature, but it is time-consuming and laborious, and the material utilization rate is low. The cost is high; the other is the inkjet printing process, which uses a solvent to dissolve the OLED material into a uniform solution, and then sprays the solution directly on the surface of the substrate to form an RGB organic light-emitting layer. The material utilization rate is high, the operation is simple, and the cost is low. With its unique technical characteristics and production advantages, inkjet printing is gradually becoming the mainstream production process of OLED panels, which will change the production mode of the entire display industry.

經過結構修飾後，不僅具有高遷移率和三綫態能級，同時具備較好的穩定性和溶解性，可作爲空穴傳輸材料應用於噴墨打印OLED器件。BTBF芳胺衍生物的合成一般是通過不同的合環方法製備BTBF，再進行溴化得到BTBF-2Br

，再繼續與二芳胺經偶聯反應得到BTBF芳胺衍生物。發明專利1[CN110981889A]公開了BTBF類空穴傳輸材料的合成方法及在蒸鍍OLED器件的應用，其中未對關鍵中間體BTBF的合成工藝進行表述，同時其合成BTBF産品都需經過柱層析純化，無放大可行性；發明專利2[CN106883248A]公開了BTBF中間體的合成，雖然該方法具有路綫短（2步）的優勢，但原料價格昂貴，而且進行Suzuki偶聯反應選擇性較差，難以分離提純，可行性較低。文獻1[Angew. Chem. Int. Ed. 10.1002/anie.201801982]報道了中間體BTBF的合成，但需用到三氟化硼乙醚溶液，反應劇烈危險性高，不適合工業放大。文獻2[Chemistry Letters 2018, Vol.47, No.8, 1044-1047]也報道了中間體BTBF的合成，但第一步採用甲苯溶劑産品轉化率較低，經鑒定是反應産生原料脫溴的副産物多。第二步採用新戊酸銀價格昂貴不易得，兩步都需柱層析，所以該工藝還需繼續優化，不具備放大可行性。文獻3[Organic Electronics 84 (2020) 105793]報道的BTBF芳胺衍生物的合成方法（如以下路綫所示），需經過8步反應得到BTBF-DPA，其中需要用到DIBAL-H和液溴等危險性較高的試劑，而且路綫長，耗時長，總收率低，不適合進行工業放大反應，而且合成的材料純度不足（99.27%，含有多鹵代雜質），可能是BTBF-2Br的合成採用液溴，容易發生多鹵代反應，柱層析提純困難。BTBF-2Br純度低，對合成終産品BTBF-DPA的純度有直接影響。純度較差的材料製作的打印OLED器件的效率和壽命都會降低。所以綜合以上因素，迫切需要開發新工藝得到高純的BTBF芳胺衍生物，避免純度和雜質對OLED器件的影響。

At present, poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate (PEDOT:PSS), as a hole transport material for OLED, has excellent hole mobility and film-forming properties, and because of its good dissolution It can be configured as a uniform solution for printing OLED devices. However, because PEDOT:PSS is sensitive to water and easy to absorb moisture, it has a great impact on the efficiency and life of OLED devices, so it is still limited in practical applications. Benzofuran or benzothiophene compounds have relatively important applications in the field of OLEDs due to their high carrier mobility and high triplet energy level. Among them, benzothienobenzofuran (BTBF) arylamine derivatives

After structural modification, it not only has high mobility and triplet energy level, but also has good stability and solubility, and can be used as a hole transport material for inkjet printing OLED devices. The synthesis of BTBF arylamine derivatives is generally prepared by different ring closure methods to prepare BTBF, and then brominated to obtain BTBF-2Br

, and then continue to obtain BTBF arylamine derivatives through coupling reaction with diarylamine. Invention patent 1 [CN110981889A] discloses the synthesis method of BTBF-like hole transport materials and its application in vapor-deposited OLED devices. It does not describe the synthesis process of the key intermediate BTBF, and its synthesis of BTBF products requires column chromatography Purification, no amplification feasibility; Invention Patent 2 [CN106883248A] discloses the synthesis of BTBF intermediates. Although this method has the advantage of short route (2 steps), the raw material is expensive, and the selectivity of Suzuki coupling reaction is poor, so it is difficult to Separation and purification, the feasibility is low. Document 1 [Angew. Chem. Int. Ed. 10.1002/anie.201801982] reported the synthesis of intermediate BTBF, but it needs to use boron trifluoride ether solution, the reaction is violent and dangerous, and it is not suitable for industrial scale-up. Document 2 [Chemistry Letters 2018, Vol.47, No.8, 1044-1047] also reported the synthesis of the intermediate BTBF, but the conversion rate of the product using toluene solvent in the first step was low, and it was identified that the reaction resulted in the debromination of the raw material Many by-products. The second step uses silver pivalate, which is expensive and difficult to obtain, and both steps require column chromatography, so the process needs to be further optimized, and it is not feasible to scale up. The synthesis method of BTBF arylamine derivatives reported in Document 3 [Organic Electronics 84 (2020) 105793] (as shown in the following route) requires 8 steps of reaction to obtain BTBF-DPA, which requires the use of DIBAL-H and liquid bromine, etc. Highly dangerous reagent, and the route is long, time-consuming, and the total yield is low. It is not suitable for industrial scale-up reactions, and the purity of the synthesized material is insufficient (99.27%, containing polyhalogenated impurities). It may be the synthesis of BTBF-2Br The use of liquid bromine is prone to polyhalogenation reactions and difficult to purify by column chromatography. The low purity of BTBF-2Br has a direct impact on the purity of the final product BTBF-DPA. The efficiency and lifetime of printed OLED devices made of poorly pure materials will be reduced. Therefore, based on the above factors, it is urgent to develop a new process to obtain high-purity BTBF aromatic amine derivatives, so as to avoid the influence of purity and impurities on OLED devices.

In order to solve the problems existing in the prior art, the present invention proposes a synthetic route and process method suitable for large-scale production of BTBF arylamine derivatives on the basis of the above-mentioned method by comparing the advantages and disadvantages of various routes through a large number of patents and literature research. Purification can be carried out by distillation, crystallization, and sublimation, avoiding column chromatography purification, and has the advantages of short route, easy purification, short time consumption, and high product purity.

； （2）將中間體BTBF-2Br與胺R ₁R ₂NH採用Buchwald-Hartwig反應得到目標化合物，其中三(二亞苄基丙酮)二鈀和三叔丁基膦四氟硼酸鹽分別爲催化劑和配體，以叔丁醇鈉或叔丁醇鉀爲反應碱，二甲苯爲溶劑，

。 In order to achieve the above object, the present invention adopts the following technical scheme: A method for synthesizing BTBF arylamine derivatives represented by formula (I), wherein R ₁ and R ₂ are independently substituted or unsubstituted C6-C60 aryl, C6 -C60 heteroaryl group, C6-C60 condensed ring aryl group or R ₁ , R ₂ bonded to form a parallel ring, the substitution is substituted by C1-C4 alkyl, C1-C4 alkoxy or phenyl, the The heteroatom in the heteroaryl group is at least one of S, N, and O, and its synthesis method includes the following two steps: (1) The synthesis of the intermediate BTBF-2Br is based on N,N-dimethylformamide Solvent, take BTBF as raw material, adopt N-bromobutanediimide to carry out bromination reaction, obtain intermediate BTBF-2Br,

; (2) The target compound is obtained by reacting the intermediate BTBF-2Br with the amine R ₁ R ₂ NH using Buchwald-Hartwig, in which tris(dibenzylideneacetone) dipalladium and tri-tert-butylphosphine tetrafluoroborate are catalysts respectively And ligand, with sodium tert-butoxide or potassium tert-butoxide as reaction base, xylene as solvent,

.

The bromination reaction in the step (1) is slowly adding the N,N-dimethylformamide solution of N-bromosuccinimide to the N,N-dimethylformamide solution of BTBF , the reaction temperature is 0~10℃, and the reaction time is 8~20h.

The amount of reaction solvent added to the bromination reaction was 1g/18ml (BTBF-2Br/N,N-dimethylformamide), the amount of N-bromosuccinimide was 2.6 equivalents, and the reaction temperature was 5°C.

The step (1) also includes the purification of the reaction product BTBF-2Br, and the purification method is a recrystallization method; the crystallization solvent ratio is 1g solid, and 2~8ml/5~15ml mixed solvent (tetrahydrofuran/n-hexane) is used for recrystallization. Crystallize twice, then add 1g of solid to 5ml~15ml of n-hexane for slurry purification; wherein, the crystallization temperature is 10~30°C, and the crystallization time is 2~10h. Among them, the preferred reaction solvent is 1g/18ml, the N-bromosuccinimide is 2.6 equivalents, and the reaction temperature is 5°C.

The Buchwald-Hartwig reaction condition of step (2) is that catalyst tris(dibenzylideneacetone) dipalladium is 1%～5% equivalent, and ligand tri-tert-butylphosphine tetrafluoroborate is 2%～10% equivalent, reaction The alkali sodium tert-butoxide is 2.1~3.0 equivalents, xylene is the reaction solvent, the reaction temperature is 130°C, and the reaction time is 4 hours.

After the step (2), it also includes post-reaction treatment and purification steps. The post-reaction treatment is to first add methanol equal to the volume of the reaction solution, stir to precipitate the product, and filter to obtain the crude product; then dissolve it with toluene and perform silica gel filtration to desalt Carry out water washing again 3 times, described purification comprises recrystallization purification and/or sublimation purification step, described purification is to add equal volume methanol crystallization 1 time in the toluene solution after water washing, then repeat toluene dissolution and methanol crystallization 2 A product of more than 99.5% is obtained once; the sublimation purification is to sublimate the crude product twice, wherein the sublimation temperature is 240-320°C, and the sublimation time is 3-10h, and a high-purity product with a purity of more than 99.9% is obtained.

Wherein the synthetic method of BTBF is: Step 1-1: adopt 3-bromobenzothiophene, phenol as raw material, adopt copper acetylacetonate, iron triacetylacetonate as catalyst, triphenylphosphine oxide as ligand, potassium carbonate Or sodium is used as alkali, and phenol is used as solvent to carry out etherification reaction to obtain 3-phenoxybenzo[b]thiophene; Step 1-2: adopt palladium pivalate, palladium trifluoroacetate or palladium acetate as catalyst, sodium acetate, acetic acid Potassium or silver acetate is used as basic condition, pivalic acid is used as solvent, and 3-phenoxybenzo[b]thiophene is ring-closed to obtain BTBF.

The etherification reaction conditions of the step 1-1 are as follows: phenol is used as a solvent, the raw material 3-bromobenzothiophene is 1 equivalent, and the catalyst copper acetylpyruvate and iron triacetylacetonate are 2% to 10% equivalent. The body triphenylphosphine oxide is 8%~16% equivalent, potassium carbonate is 2~6 equivalent; the reaction temperature is 120°C~165°C, and the reaction time is 6~24h.

Preferably, copper acetylacetonate is 3% equivalent, iron triacetylacetonate is 6% equivalent, triphenylphosphine oxide is 12% equivalent, potassium carbonate is 4 equivalent, the reaction temperature is 150°C, and the reaction time is 8h.

The ring closing reaction conditions of the step 1-2 are as follows: 3-phenoxybenzo[b]thiophene is dissolved in a solvent, the reaction temperature is 120°C-145°C, and the reaction time is 8-12h. Preferably, the catalyst is palladium pivalate and the base is silver acetate.

The method also includes purification of the reaction product in step 1-1 and purification of the reaction product BTBF in step 1-2, wherein the purification of the reaction product in step 1-1 is collected and purified by vacuum distillation to obtain a product with a purity of more than 99%; Wherein, the distillation temperature is 80°C~160°C, and the distillation pressure is 20°C~120Pa.

The purification of the reaction product BTBF in step 1-2 adopts the recrystallization method; the crystallization solvent ratio is 1g solid, and 2~5ml/5~10ml mixed solvent (toluene/ethanol) is used for recrystallization twice, and the crystallization temperature is 5~20°C. The crystallization time is 2~10h.

In the recrystallization method, the ratio of toluene/ethanol to 1g of solid is 3ml/6ml, the crystallization temperature is 5°C, and the crystallization time is 4h.

4 5 6

7 8 9

10 11 12

13 14 15

16 17 18

19 20 21

22 23 24

      。 The BTBF arylamine derivative shown in formula (I) is any one of the following compounds: 1 2 3

4 5 6

7 8 9

10 11 12

13 14 15

16 17 18

19 20 twenty one

twenty two twenty three twenty four

.

The BTBF arylamine derivative synthesized by the invention can be prepared into a uniform solution with various solvents, and used as a hole transport layer material for inkjet printing OLED devices.

The preparation method proposed by the present invention overcomes the disadvantages of long synthetic route in the original preparation method, high risk of reagents used, and poor purification. The main advantages are: 1. The method for synthesizing intermediate BTBF in reference 2, the first step of the present invention The raw material phenol is used instead of toluene as the solvent, which greatly improves the yield, and at the same time reduces the generation of by-products of raw material debromination, and can remove various impurities through distillation and section collection; the second step uses silver acetate instead of silver pivalate to reduce material costs. ; two-step reaction without column chromatography purification. 2. For the method of synthesizing BTBF arylamine derivatives in Comparative Document 3, the steps of the route of the present invention are reduced to 4 steps, the yield is high, the time consumption is short, and no high-risk reagents are used, and the process safety is high; 3. The synthesis of BTBF-2Br uses N-bromobutanediimide (NBS) replaces liquid bromine reaction, which can reduce polyhalogenated impurities and is easy to purify; the whole process does not need column chromatography purification, and methods such as distillation, recrystallization, and sublimation are used to effectively improve the The purity of BTBF arylamine derivatives, the high-purity products that can be obtained, are beneficial to avoid the influence of impurities on the performance of OLED devices.

The present invention will be further described in detail below in conjunction with the examples.

Embodiment 1 The synthesis of intermediate BTBF:

1-1 Synthesis of intermediate 3-phenoxybenzo[b]thiophene In a 1L three-necked flask, add 3-bromobenzothiophene (55g, 258.1mmol, 1.0eq), phenol (364.35g, 3.87mol, 15.0eq), copper acetylacetonate (2.03g, 7.74mmol, 0.03eq), iron triacetylacetonate (5.47g, 15.49mmol, 0.06eq), triphenylphosphine oxide (8.62g, 30.97mmol, 0.12eq) , Potassium carbonate (142.68g, 1.03mol, 4.0eq), vacuum, nitrogen replacement 3 times, heated to 150 ° C for 8 hours, sampling for TLC plate, showing that 3-bromobenzothiophene basically reacted completely, that is, the reaction was stopped. After cooling to room temperature, deionized water (250 ml) and ethyl acetate (250 ml) were added to the reaction solution, stirred and washed with water, and separated. The upper organic phase was collected, and the aqueous phase was extracted once more with ethyl acetate (100 ml). The organic phase was collected, combined and concentrated twice. The concentrated crude product was subjected to vacuum distillation, and impurities and products were collected in sections. Use a mechanical pump to reduce the pressure of the reaction bottle to about 30Pa, and raise the temperature of the reaction device to 85°C. When the distillation temperature of the system reaches 73°C, start to distill out the phenol solvent and benzothiophene impurities, and collect the fraction ①; wait until no distillate flows out After that, the temperature was raised to 155°C. When the distillation temperature reached 143°C, the product was gradually distilled out, and a small amount of 3-5g of impure product was collected in fraction ②; the product was collected by distillation again, which was fraction ③, and the white oily substance 3-benzene Oxybenzo[b]thiophene (45.64g, yield 78.15%, purity 99.53%). Mass spectrum: 227.29 (M+H). ¹ H NMR (400 MHz, CDCl ₃ ) δ 7.90 – 7.76 (m, 2H), 7.47 – 7.34 (m, 4H), 7.23 – 7.12 (m, 3H), 6.72 (d , J = 2.6 Hz, 1H).

1-2 Synthesis of intermediate BTBF: In a 1L three-neck flask, add 3-phenoxybenzo[b]thiophene (28g, 123.73mmol, 1.0eq), palladium pivalate (1.76g, 6.19mmol, 0.05 eq), silver acetate (41.31g, 247.47mmol, 2.0eq), pivalic acid (189.5g, 1.86mol, 15.0eq), vacuum and nitrogen replacement 3 times, stirred and heated to 120°C under nitrogen protection, and reacted for 12h. Samples were taken for TLC spotting. The reaction of 3-phenoxybenzo[b]thiophene was complete, so the heating was stopped and the temperature was lowered to room temperature. Add 200ml of deionized water and ethyl acetate (250ml) to the reaction solution, stir, wash with water, and separate liquids. Collect the organic phase and filter it with diatomaceous earth. The filtrate is concentrated and dried to obtain a crude product. The crude product was heated to 90°C with toluene (83ml), stirred and dissolved completely, after cooling to room temperature, ethanol (166ml) was added, cooled to 5°C, stirred and crystallized for 4h, and an off-white solid was obtained by suction filtration. Repeat the toluene/ethanol crystallization again (solvent ratio: product/toluene/ethanol=1g/3ml/6ml) to obtain white solid BTBF (24.07g, yield 86.73%, purity 99.65%). Mass spectrum: 225.28 (M+H). ¹ H NMR (400 MHz, CDCl ₃ ) δ 8.02 (d, J = 7.6 Hz, 1H), 7.89 (d, J = 8.1 Hz, 1H), 7.78 – 7.70 (m, 1H), 7.66 (d, J = 7.7 Hz, 1H), 7.47 (d, J = 7.2 Hz, 1H), 7.45 – 7.27 (m, 3H).

Example 2 Synthesis of intermediate BTBF-2Br: In a 500mL three-neck flask, add BTBF (22.35g, 99.65mmol, 1.0eq), N,N-dimethylformamide (268ml) respectively, and replace with vacuum and nitrogen for 3 Next, under the protection of nitrogen, the temperature of the reaction solution was lowered to 5°C, while N-bromosuccinimide (46.12g, 259.1mmol, 2.6eq) was dissolved in N,N-dimethylformamide (138ml) , and slowly added dropwise to the original reaction solution, with a time of 0.5h. After the dropwise addition, return to room temperature and react for 6h. Samples were taken for TLC spotting, and BTBF had completely reacted. The reaction solution was added to a 1L single-necked bottle filled with deionized water (487ml), stirred for 1h, a solid was precipitated, and the solid was collected by filtration. The solid was added to tetrahydrofuran (152ml), heated to 60°C, stirred and dissolved completely, after cooling to room temperature, n-hexane (456ml) was added, cooled to 10°C, stirred and crystallized for 3h, and filtered to obtain a solid. The tetrahydrofuran/n-hexane crystallization was repeated once more (solvent ratio: product/tetrahydrofuran/n-hexane=1g/4ml/12ml), and a solid was obtained by filtration. The solid was added into n-hexane (300ml) for stirring and beating for 2h, and filtered to obtain a white solid BTBF-2Br (27.89g, yield 73.25%, purity 99.12%). Mass spectrum: 383.07 (M+H). ¹ H NMR (400 MHz, CDCl ₃ ) δ 8.01 (s, 1H), 7.82 (dd, J = 13.3, 4.9 Hz, 2H), 7.61 – 7.55 (m, 2H), 7.49 (s, 1H).

Example 3 Synthesis of Compound 1: In a 500mL three-necked flask, BTBF-2Br (10.3g, 26.96mmol, 1.0eq), diphenylamine (10.95g, 64.70mmol, 2.4eq), sodium tert-butoxide (7.77g , 80.88mmol, 3.0eq), tris(dibenzylideneacetone)dipalladium (0.74g, 808.7umol, 0.03eq) and tri-tert-butylphosphine tetrafluoroborate (0.46g, 1.62mmol, 0.06eq), anhydrous Xylene (150 mL) was replaced with vacuum and nitrogen three times, heated to 130 °C under the protection of nitrogen, and reacted for 4 hours. Sampling for TLC plate, BTBF-2Br has been completely reacted. After cooling down to room temperature, methanol (150 ml) was slowly added to the reaction solution, stirred for 1 h, and a solid precipitated out, which was collected by filtration. Add the solid to toluene (225ml), heat to 102°C, stir to dissolve completely, after cooling to room temperature, pour it into a funnel equipped with silica gel (40g, 200~300 mesh), filter and collect the filtrate, then add Wash with deionized water 3 times (75ml each time), collect the toluene phase by liquid separation, then slowly add methanol (225ml) dropwise, stir and crystallize for 3h, and filter to obtain the crude product. Repeated crystallization and purification with toluene and methanol twice (solvent ratio: product/toluene/methanol=1g/15ml/15ml) to obtain white solid compound 1 (12.45g, yield 82.64%, purity 99.89%), 12.45 grams of crude product , sublimated at 260°C for 7 hours under a vacuum of 3.2*10 ^-4 Pa to obtain sublimated pure compound 1 (10.2 g, yield 81.92%, purity 99.98%). Mass spectrum: 559.69 (M+H).) ¹ H NMR (400 MHz, CDCl ₃ ) δ 7.75 (d, J = 8.6 Hz, 1H), 7.50 (d, J = 8.8 Hz, 2H), 7.36 – 7.19 (m , 10H), 7.18 – 6.94 (m, 13H).

The present invention compares with the synthetic process result of document 2, document 3: Process result comparison Literature 2 Synthetic process Document 3 Synthetic Process Synthetic process of the present invention Synthetic yield of each step 3-Phenoxybenzo[b]thiophene (Step 1) 15.14% 3-Phenoxybenzo[b]thiophene (Steps 1-4) 27.73% 3-Phenoxybenzo[b]thiophene (Step 1-1) 78.15% Intermediate BTBF (step 2) 55.32% Intermediate BTBF (steps 5-6) 78.22% Intermediate BTBF (steps 1-2) 86.73% Intermediate BTBF-2Br (step 7) 26.39% Intermediate BTBF-2Br (step 7) 26.39% Intermediate BTBF-2Br Example 2 73.25% / Compound 1 (Step 8) 80.52% Compound 1 82.64% total yield / 4.61% 41.02% Compound 1 purity / 99.27% 99.98% Synthesis and purification process ① Step 1 uses toluene as a solvent, and the yield is low; ② Step 2 uses silver pivalate, which is expensive; ③ Both steps of reaction require column chromatography purification. ①The reaction conditions are relatively harsh, and dangerous reagents such as trifluoroacetic acid, hydrogen peroxide, diisobutylaluminum hydride, and liquid bromine need to be used; ②Column chromatography purification is required for each step; ③The purity of the product obtained by synthesis is only 99.27%, and ④The total The yield is low, and the synthesis steps are 8 steps and take a long time. ① The raw materials are easy to get, and there is no use of high-risk reagents; ② Step 1-1 uses phenol as a solvent, which greatly improves the yield; Step 1-2 uses silver acetate instead of silver pivalate, and the raw materials are cheap and easy to get; Example 2 NBS bromination is used, which has high safety and less side reactions; ③The 4-step reaction product is purified by distillation, crystallization, and sublimation, which is feasible to scale up; ④The final product has high purity and high overall yield.

Example 4 Synthesis of compound 3: In a 500mL three-necked flask, BTBF-2Br (8.65g, 22.4mmol, 1.0eq), bis(4-biphenyl)amine (17.28g, 53.77mmol, 2.4eq), Sodium tert-butoxide (6.46g, 67.21mmol, 3.0eq), tris(dibenzylideneacetone)dipalladium (0.61g, 672.1umol, 0.03eq) and tri-tert-butylphosphine tetrafluoroborate (0.39g, 1.34 mmol, 0.06eq), anhydrous xylene (128mL), vacuum and nitrogen replacement 3 times, heated to 130 ℃ under the protection of nitrogen, and reacted for 4h. Sampling for TLC plate, BTBF-2Br has been completely reacted. After cooling down to room temperature, methanol (128 ml) was slowly added to the reaction solution, stirred for 1 h, and a solid precipitated out, which was collected by filtration. Add the solid to toluene (290ml), heat to 105°C, stir to dissolve completely, and after cooling to room temperature, pour it into a funnel equipped with silica gel (40g, 200~300 mesh), collect the filtrate by filtration, and then add Wash with deionized water 3 times (90ml each time), collect the toluene phase by liquid separation, then slowly add methanol (290ml) dropwise, stir and crystallize for 3h, and filter to obtain the crude product. Repeated crystallization and purification with toluene and methanol twice (solvent ratio: product/toluene/methanol=1g/15ml/15ml) to obtain white solid compound 3 (15.34g, yield 79.34%, purity 99.86%), 11.83 grams of crude product , sublimated at 293°C for 8.5 hours at a vacuum of 2.6*10 ^-4 Pa to obtain sublimated pure compound 3 (11.63 g, yield 75.81%, purity 99.98%). Mass spectrum: 864.0 (M+H). ¹ H NMR (400 MHz, CDCl ₃ ) δ 7.86 (d, J = 8.4 Hz,1H), 7.74 (d, J = 5.0 Hz, 9H), 7.61 (d, J = 8.7 Hz, 1H), 7.52 (m, 17H), 7.39 (d, J = 20.0 Hz, 12H), 7.21 (dd, 1H), 7.03 (dd , 1H).

Example 5 Synthesis of Compound 9 In a 500mL three-necked flask, BTBF-2Br (7.36g, 19.26mmol, 1.0eq), N-[1,1'-biphenyl]-2-yl-9,9-di Methyl-9H-fluoren-2-amine (16.71g, 46.23mmol, 2.4eq), sodium tert-butoxide (5.55g, 57.79mmol, 3.0eq), tris(dibenzylideneacetone)dipalladium (0.52g, 577.9umol, 0.03eq) and tri-tert-butylphosphine tetrafluoroborate (0.33g, 1.16mmol, 0.06eq), anhydrous xylene (110mL), vacuum, nitrogen replacement 3 times, heated to 130 °C under nitrogen protection, Reaction 3.5h. Sampling for TLC plate, BTBF-2Br has been completely reacted. After cooling down to room temperature, methanol (110 ml) was slowly added to the reaction solution, stirred for 1 h, and a solid precipitated out, which was collected by filtration. Add the solid to toluene (270ml), heat to 95°C, stir to dissolve completely, and after cooling to room temperature, pour it into a funnel equipped with silica gel (40g, 200~300 mesh), filter and collect the filtrate, then add Wash with deionized water 3 times (90ml each time), collect the toluene phase by liquid separation, then slowly add methanol (270ml) dropwise, stir and crystallize for 3h, and filter to obtain the crude product. Repeated crystallization and purification with toluene and methanol twice (solvent ratio: product/toluene/methanol=1g/15ml/15ml) to obtain white solid compound 9 (13.88g, yield 76.38%, purity 99.91%). 13.88 g of the crude product were sublimed at 315°C for 8 h under a vacuum of 2.9*10 ^-4 Pa to obtain sublimated pure compound 9 (10.63 g, yield 76.58%, purity 99.97%). Mass spectrum: 944.2 (M+H). ¹ H NMR (400 MHz, CDCl ₃ ) δ 8.10 (d, J = 9.3 Hz ,2H), 8.03 (d, J = 8.6 Hz ,1H), 7.88 (m, 4H) , 7.74 (d, J = 8.4 Hz ,1H), 7.65 – 7.49 (m, 5H), 7.40 (m, 13H), 7.26 (m, 4H), 7.18 – 6.99 (m, 8H), 1.69 (s, 12H ).

PEDOT-PSS            對比材料：PVK                           GD                                     Host 1

Host 2                                         ETL                                   EIL Application example: Fabrication of organic electroluminescent devices A 50mm*50mm*1.0mm glass substrate with an ITO (100nm) transparent electrode was ultrasonically cleaned in ethanol for 10 minutes, then dried at 150 degrees and treated with N ₂ Plasma for 30 minutes. A hole injection layer (HIL, 10 nm) using PEDOT-PSS was inkjet printed onto the substrate and dried in vacuum. The HIL was then annealed at 185 °C for 30 min in air. The high-purity materials synthesized in Examples 3-5, comparative compound 1 (purity 99.27%), and comparative material PVK were prepared into solution AF (the solvent was methyl benzoate, the concentration was 23 mg/ml), and inkjet printing was performed on HIL Above (20nm), as a hole transport layer (HTL, 20nm), dried in vacuum, and then annealed at 210°C for 30 minutes in a nitrogen atmosphere. The green light-emitting layer (G-EML, 15nm) was inkjet printed, dried in vacuum, and then annealed at 160° C. for 10 minutes in a nitrogen atmosphere. The ink used for the green light-emitting layer contains two host materials (ie Host 1 and Host 2) and a green dopant material (GD), and the solvent is cyclohexylbenzene. The ratio of host material and dopant material is 47%:47%:6%. Then the device was transferred to a vacuum deposition chamber, where an ETL film (25nm) and a LiQ film (1nm) were sequentially deposited on the light-emitting layer, and finally a layer of metal Al (100nm) was deposited as an electrode.

PEDOT-PSS comparison material: PVK GD Host 1

Host 2 ETL EIL

Evaluation: The above-mentioned devices were tested for device performance. In each example and comparative example, a constant current power supply (Keithley 2400) was used, a fixed current density was used to flow through the light-emitting element, and a spectroradiometer (CS 2000) was used to test the luminescence spectrum. At the same time, measure the voltage value and the time when the test brightness is 90% of the initial brightness (LT90). The result is as follows: HTL material Starting voltage/V Current efficiency Cd/A Peak wavelength nm LT90 @3000nits Device 1 Solution A (Compound 1) 4.66 56 525 158 Device 2 Solution B (Compound 3) 4.73 58 526 165 Device 3 Solution C (Compound 9) 4.76 59 525 163 Comparative example 1 Solution D (compound 1 purity 99.27%) 4.97 50 525 136 Comparative example 2 Solution E (PVK) 5.07 51 524 144

From the comparison of the data in the above table, it can be seen that the high-purity material compound 1, compound 3, and compound 9 obtained by the synthesis process of the present invention in devices 1-3 are used as hole transport layer ink material solutions A-C to prepare OLED devices. Voltage, efficiency lifespan is better than Comparative Example 1 (solution D, compound 1 purity 99.27%), indicating that the purity of the material, organic impurities, and inorganic impurities have a greater impact on the performance of the device, and the high-purity material synthesized by the process of the present invention embodies superior device performance. At the same time, compared with the solution E prepared from the traditional material PVK in Comparative Example 2 as the ink material of the hole transport layer, the devices 1-3 also showed more superior performance.

According to the synthesis process results of Examples 3-5, the present invention has the advantages of short process route, easy access to raw materials, high total yield, and high product purity. At the same time, each step can be purified by distillation, recrystallization, sublimation, etc. Scale up production feasibility. The performance of printed OLED devices according to the application examples shows that the high-purity BTBF arylamine derivatives obtained by the process of the present invention, as a hole transport ink material, can effectively improve the luminous efficiency and life of printed OLED devices, and have the potential to be used in inkjet printed OLEDs. Possibility of technical mass production.

Fig. 1 is the HNMR spectrogram of 3-phenoxybenzo [b] thiophene; Fig. 2 is the HNMR spectrogram of BTBF; Fig. 3 is the HNMR spectrogram of BTBF-2Br; And FIG. 4 is the HNMR spectrum of compound 1.

Claims (10)

A method for synthesizing BTBF arylamine derivatives represented by formula (I), wherein R ₁ and R ₂ are independently substituted or unsubstituted C6-C60 aryl, C6-C60 heteroaryl, C6-C60 condensed Ring aryl or R ₁ , R ₂ are bonded to form a parallel ring, the substitution is substituted by C1-C4 alkyl, C1-C4 alkoxy or phenyl, and the heteroatoms in the heteroaryl are S, N , O, and its synthesis method includes the following two steps: (1) The synthesis of intermediate BTBF-2Br uses N,N-dimethylformamide as solvent and BTBF as raw material, using N-bromo Succinimide carries out bromination reaction, obtains intermediate BTBF-2Br,

; (2) The target compound is obtained by reacting the intermediate BTBF-2Br with the amine R ₁ R ₂ NH using Buchwald-Hartwig, in which tris(dibenzylideneacetone) dipalladium and tri-tert-butylphosphine tetrafluoroborate are catalysts respectively And ligand, with sodium tert-butoxide or potassium tert-butoxide as reaction base, xylene as solvent,

. The synthesis method as described in claim 1, wherein, the bromination reaction in the step (1) is slowly adding N,N-dimethylformamide solution of N-bromosuccinimide to BTBF In N,N-dimethylformamide solution, the reaction temperature is 0~10℃, and the reaction time is 8~20h. The synthetic method as described in claim item 2, wherein, in the bromination reaction, the reaction solvent addition amount BTBF-2Br/N, N-dimethylformamide is 1g/18ml, and N-bromosuccinimide is 2.6 equivalents, the reaction temperature is 5°C. The synthesis method as described in claim item 2, wherein, after the step (1), the purification of the reaction product BTBF-2Br is also included, and the purification method is a recrystallization method; the ratio of the crystallization solvent is 1g solid and 2~8ml/ 5~15ml mixed solvent tetrahydrofuran/n-hexane is used for recrystallization twice, and then 1g of solid is added to 5ml~15ml of n-hexane for beating and purification; the crystallization temperature is 10~30°C, and the crystallization time is 2~10h. The synthetic method as described in claim item 1, wherein, the Buchwald-Hartwig reaction condition of the step (2) is that the catalyst tris(dibenzylideneacetone) dipalladium is 1%~5% equivalent, and the ligand tri-tert-butyl Phosphine tetrafluoroborate is 2%~10% equivalent, sodium tert-butoxide is 2.1~3.0 equivalent, xylene is the reaction solvent, the reaction temperature is 130°C, and the reaction time is 4h. The synthesis method as described in claim item 5, wherein, after the step (2), it also includes post-reaction treatment and purification steps. The post-reaction treatment is to add methanol equal to the volume of the reaction solution, stir and precipitate the product, and filter to obtain Crude product; then dissolved in toluene, desalinated by silica gel filtration; then washed 3 times, the purification includes recrystallization purification and/or sublimation purification steps, the purification is crystallization by adding an equal volume of methanol to the toluene solution after washing Once, repeat toluene dissolution and methanol crystallization twice to obtain more than 99.5% of the product; the sublimation purification is to carry out two sublimation of the crude product, wherein the sublimation temperature is 240~320°C, and the sublimation time is 3~10h to obtain 99.9% High-purity products with the above purity. The synthesis method as described in claim item 1, wherein the synthesis method of BTBF is: Step 1-1: 3-bromobenzothiophene and phenol are used as raw materials, copper acetylacetonate and iron triacetylacetonate are used as catalysts, triphenylphosphine oxide is used as ligand, potassium carbonate or sodium is used as base, and phenol is used as The solvent is etherified to obtain 3-phenoxybenzo[b]thiophene; Step 1-2: Using palladium pivalate, palladium trifluoroacetate or palladium acetate as catalyst, sodium acetate, potassium acetate or silver acetate as alkaline condition, pivalic acid as solvent, 3-phenoxybenzo[b] Thiophene ring closure reaction gives BTBF. The synthetic method as described in claim item 7, wherein, the etherification reaction conditions of the step 1-1 are: phenol is used as a solvent, the raw material 3-bromobenzothiophene is 1 equivalent, the catalyst is copper acetylpyruvate and triethylpyruvate Iron acetonate is 2%~10% equivalent, ligand triphenylphosphine oxide is 8%~16% equivalent, potassium carbonate is 2~6 equivalent; the reaction temperature is 120°C~165°C, and the reaction time is 6~24h; The ring closure reaction conditions of step 1-2 are as follows: 3-phenoxybenzo[b]thiophene is dissolved in a solvent, the reaction temperature is 120°C~145°C, and the reaction time is 8~12h. 9. The synthesis method according to claim 8, wherein the method further comprises step 1-1 reaction product purification and step 1-2 reaction product BTBF purification, the step 1-1 reaction product purification adopts decompression Distillation is collected and purified in sections to obtain a product with a purity of more than 99%. Among them, the distillation temperature is 80°C~160°C, and the distillation pressure is 20°C~120Pa; The purification of the reaction product BTBF in step 1-2 adopts the recrystallization method; the crystallization solvent ratio is 1g solid, and 2~5ml/5~10ml mixed solvent toluene/ethanol is used for recrystallization twice, the crystallization temperature is 5~20°C, and the crystallization temperature is 5~20°C. The time is 2~10h. 10. The synthesis method according to any one of claims 1-9, wherein the BTBF arylamine derivative represented by formula (I) is any one of the following compounds: The synthesis method as described in claim item 8, wherein, the method also includes the purification of the reaction product BTBF in step 1-1 and the purification of the reaction product BTBF in step 1-2, and the purification of the reaction product in step 1-1 is carried out by vacuum distillation Collect and purify in sections to obtain a product with a purity of more than 99%; among them, the distillation temperature is 80°C~160°C, and the distillation pressure is 20°C~120Pa; The purification of the reaction product BTBF in step 1-2 adopts the recrystallization method; the crystallization solvent ratio is 1g solid, and 2~5ml/5~10ml mixed solvent toluene/ethanol is used for recrystallization twice, the crystallization temperature is 5~20°C, and the crystallization temperature is 5~20°C. The time is 2~10h. The synthetic method as described in any one of claims 1 to 9, wherein the BTBF arylamine derivative represented by formula (I) is any one of the following compounds: 1 2 3

4 5 6

7 8 9

10 11 12

13 14 15

16 17 18

19 20 twenty one

twenty two twenty three twenty four

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