Kilogram-level preparation method of conjugated thiophene organic photoelectric intermediate reagent

Abstract

The invention provides a kilogram-level preparation method of a conjugated thiophene organic photoelectric intermediate reagent, and belongs to the technical field of organic synthesis and organic photoelectric materials. The preparation method comprises the following steps: filling a thiophene derivative raw material into a reaction bottle, adding an electrophilic reagent and a reaction solvent, and starting stirring; adding a catalyst under a protective atmosphere to carry out catalytic reaction, and monitoring the reaction by adopting a thin layer chromatography until no raw material is left; cooling a catalytic reaction product, standing, collecting an organic phase, and purifying by column chromatography to obtain the conjugated thiophene organic photoelectric intermediate reagent. By optimizing equipment configuration and process parameters, stable preparation of kilogram-level (1-2kg of conjugated thiophene compounds are produced at a single time) is realized, and the problem of yield reduction caused by an amplification effect is solved; the method has the characteristics of safe and controllable operation, high raw material utilization rate, suitability for industrial amplification and the like, and effectively fills the gap of large-scale supply of high-purity conjugated thiophene intermediates.

Description

Technical Field

[0001] This invention belongs to the field of organic synthesis and organic optoelectronic materials technology, and particularly relates to a kilogram-scale preparation method of conjugated thiophene-based organic optoelectronic intermediate reagents. Background Technology

[0002] Conjugated thiophene compounds hold an irreplaceable position in the field of organic electronic materials due to their unique photoelectric properties and are widely used in high-end manufacturing fields such as solar cells and flexible display devices. However, the preparation of these compounds has long faced the problem of a disconnect between laboratory synthesis and industrial production.

[0003] In existing technologies, the synthesis of conjugated thiophene intermediates is mostly limited to gram-scale laboratory production, which has the following limitations: First, the reaction conditions are harsh, relying heavily on expensive metal catalysts and special ligands. For example, the amount of palladium catalyst used is usually as high as 5%-10% molar ratio, which significantly increases the production cost. Second, there is a significant scale-up effect. When the reaction scale is increased from gram to kilogram, the yield often decreases by more than 30% due to changes in heat and mass transfer efficiency. Third, there is insufficient safety. The large-scale use of low-temperature reactions (such as -78℃) and flammable solvents (such as tetrahydrofuran) lacks systematic process control schemes. Fourth, the product purity is unstable. During scale-up production, the impurity content often exceeds the standards for optoelectronic materials applications (purity requirement ≥99%).

[0004] Industry reports indicate that the current market supply gap for high-purity conjugated thiophene intermediates exceeds 50 tons per year, while the production cost of existing laboratory methods is as high as 8,000-15,000 yuan per kilogram, severely hindering the development of the organic optoelectronic industry. Therefore, developing an efficient, safe, and scalable process for preparing conjugated thiophene intermediates has become an urgent technical problem to be solved in this field. Summary of the Invention

[0005] This invention aims to solve the technical problems existing in the preparation of conjugated thiophene organic photoelectric intermediates, such as difficulties in large-scale production, low yield, unstable purity, and poor safety. It proposes a kilogram-scale preparation method for conjugated thiophene organic photoelectric intermediate reagents. The method of this invention is suitable for the large-scale industrial production of conjugated thiophene organic photoelectric intermediate reagents and can meet the large-scale demand for high-purity conjugated boron reagents in fields such as drug synthesis, organic photovoltaics (OPV), organic field-effect transistors (OFETs), and organic light-emitting diodes (OLEDs).

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] This invention proposes a kilogram-scale preparation method for conjugated thiophene-based organic photoelectric intermediates, comprising the following steps:

[0008] (1) Load the thiophene derivative raw material into a reaction flask, add the electrophilic reagent and reaction solvent, and start stirring;

[0009] (2) Under a protective atmosphere, a catalyst is added to the system obtained in step (1) to carry out a catalytic reaction. The reaction is monitored by thin-layer chromatography until no raw material remains.

[0010] (3) After cooling the catalytic reaction product of step (2), add dichloromethane and water, stir and let stand to separate the phases, collect the organic phase, extract the aqueous phase with dichloromethane and collect the extracted organic phase, and combine all organic phases;

[0011] (4) The combined organic phase is dried, filtered, concentrated under reduced pressure, and then purified by column chromatography to obtain the conjugated thiophene organic photoelectric intermediate reagent, and the weight of the product prepared in one batch is 1-2 kg.

[0012] Further, in step (1), the electrophilic reagent is 2-(2-ethylhexyl)thiophene, 2-tributylmethyltinylthiophene, or 2,4,6-isopropylphenylboronic acid.

[0013] Further, in step (1), the molar ratio of the electrophilic reagent to the thiophene derivative raw material is 2.1:1-2.5:1.

[0014] Further, in step (2), the catalyst is tetra(triphenylphosphine)palladium(0) or [(1,2,4,5-η)-1,5-diphenyl-1,4-pentadien-3-one]palladium.

[0015] Further, in step (2), when the catalyst is [(1,2,4,5-η)-1,5-diphenyl-1,4-pentadien-3-one]palladium, tris(o-methylphenyl)phosphine is added, and the molar ratio of [(1,2,4,5-η)-1,5-diphenyl-1,4-pentadien-3-one]palladium to tris(o-methylphenyl)phosphine is 1:6.

[0016] Further, in step (2), the amount of catalyst used is 0.1%-1% of the molar amount of the thiophene derivative raw material.

[0017] Furthermore, in step (2), the temperature of the catalytic reaction is 85-110 °C.

[0018] Furthermore, in step (2), the protective atmosphere is a nitrogen atmosphere, and the nitrogen is purged into the reaction system for no less than 10 minutes, and the reaction is carried out under positive pressure.

[0019] Further, the conjugated thiophene-based organic photoelectric intermediate reagents include benzo[1,2-B:4,5-B']dithiophene-4,8-dione, 4,8-di-(5-(2-ethylhexyl)thiophene-2-yl)benzo[1,2-B:4,5-B']dithiophene, 1,3-bis(thiophene-2-yl)-5,7-bis(2-ethylhexyl)benzo[1,2-c:4,5-c']dithiophene-4,8-dione, 3,3'-bis-(2,4,6-triisopropylphenyl)-2,2'-bithiophene, 4,4,9,9-tetra(dodecyl)-4,9-dihydro-s-indarsen[1,2-b: [5,6-b']dithiophene, ethyl 2,5-bis(thiophene-2-yl)terephthalate, 4,4,9,9-tetra(4-hexylphenyl)-4,9-dihydro-s-benzodiindo[1,2-b:5,6-b']dithiophene, 3,3'-bis(2,4,6-trimethylphenyl)-2,2'-bidithiophene, thiophene[3,2-b]thiophene, 3-undecylthiophene[3,2-b]thiophene-2-carboxylic acid, 3-nonylthiophene[3,2-b]thiophene-2-carboxylic acid or 4,4,9,9-tetrahexyl-4,9-dihydro-s-indargenop-[1,2-b:5,6-b0]dithiophene.

[0020] Further, in step (1), the reaction solvent is N,N-dimethylformamide.

[0021] Furthermore, in step (2), when monitoring the reaction using thin-layer chromatography, the developing solvent is a mixture of petroleum ether and dichloromethane in a volume ratio of 2:1 to 3:1.

[0022] Furthermore, the conjugated thiophene organic photoelectric intermediate reagent prepared by the method of the present invention has a single yield of 1-2 kg, a crude yield of 70%-98%, and a purity of ≥99% after purification.

[0023] In addition, this invention also proposes kilogram-scale preparation methods for the following four conjugated thiophene-based organic photoelectric intermediates:

[0024] (1) Tetrahydrofuran (THF) was poured into a reaction flask, and thiophene derivative raw material was added and stirred at room temperature. Under nitrogen protection, the temperature was lowered, and then alkyl lithium reagent was slowly added dropwise. After the addition was complete, the reaction was allowed to cool naturally to room temperature. Stirring was continued at room temperature, and then the temperature was lowered and water was slowly added dropwise. After the water was added, the temperature was continued to be lowered and water was slowly added dropwise. After the water was added, the mixture was stirred continuously at room temperature. Then, the liquid was removed by vacuum filtration using a ceramic Buchner funnel and a vacuum flask. The filter cake was collected and recrystallized using toluene as a solvent to obtain the conjugated thiophene organic photoelectric intermediate reagent.

[0025] In the above preparation method, the alkyllithium reagent is a tetrahydrofuran solution of n-butyllithium or a hexane solution of tert-butyllithium; the concentration of the alkyllithium reagent is 2.0-2.5 mol / L.

[0026] (2) Add thiophene derivative raw material, potassium tert-butoxide (C4H9OK) and dimethyl sulfoxide (DMSO) at room temperature, start stirring, and then add 1-bromododecane (C 12 H 25 The reaction was monitored by thin-layer chromatography using petroleum ether as the developing solvent. After the reaction was completed, water was added and stirring was continued, resulting in the precipitation of a large amount of solid. The mixture was filtered under reduced pressure using a ceramic Buchner funnel and a vacuum flask. The filter cake was washed with water, and the filtrate was extracted with petroleum ether. The organic phase was collected and evaporated to dryness to obtain a deep yellow solid. This solid was combined with the filter cake and purified by column chromatography to obtain the conjugated thiophene organic photoelectric intermediate reagent.

[0027] (3) Ethanol (CH3CH2OH) and potassium hydroxide (KOH) were added to the reaction flask at room temperature. After cooling, the thiophene derivative raw material was slowly added dropwise. After the addition was completed, the temperature was raised to monitor the reaction. Petroleum ether was used as the developing solvent. After the reaction was completed, water was slowly added dropwise and stirring was continued. Then, the ethanol was heated and distilled off. Water was added and stirred separately. The filtrate was removed by vacuum filtration using a ceramic Buchner funnel and a vacuum flask to obtain the conjugated thiophene organic photoelectric intermediate reagent.

[0028] (4) Add thiophene derivative raw material, copper powder and quinoline at room temperature, start stirring, monitor the reaction by thin layer chromatography, use dichloromethane as the developing solvent, cool to room temperature after the reaction is complete, add dichloromethane and water, stir and let stand to separate phases; collect the lower organic phase, add water to it and stir repeatedly to separate phases, collect the lower organic phase, add anhydrous magnesium sulfate, stir and dry to remove water, use ceramic Buchner funnel and vacuum filtration flask to remove magnesium sulfate solid, collect the filtrate, and use rotary evaporator to concentrate the filtrate under reduced pressure to obtain brownish-gray solid, preliminarily purify by column chromatography to obtain conjugated thiophene organic photoelectric intermediate reagent.

[0029] Compared with the prior art, the present invention has the following advantages and technical effects:

[0030] 1. Large-scale production capacity: By optimizing equipment configuration and process parameters, stable preparation of kilogram-level (1-2 kg per batch) conjugated thiophene compounds has been achieved, solving the problem of yield reduction caused by scale-up effect;

[0031] 2. High yield and high purity: The crude yield of the product can reach 70%-98%, and the purity after purification is ≥99%, which meets the detection standards of nuclear magnetic resonance hydrogen spectrum, carbon spectrum and mass spectrometry;

[0032] 3. Process safety: A complete system for low-temperature reaction control, inert gas protection, and solvent recovery has been established, reducing the operational risks associated with flammable reagents and corrosive substances;

[0033] 4. Cost advantage: By optimizing the catalyst dosage (reducing it to a molar ratio of 0.1%-1%), production costs are significantly reduced;

[0034] 5. High versatility: This process is applicable to the preparation of various conjugated thiophene derivatives such as benzodithiophene and bithiophene, and the reaction parameters can be adjusted according to requirements to produce different types of products;

[0035] 6. Verification by nuclear magnetic resonance hydrogen spectroscopy, carbon spectroscopy and mass spectrometry shows that the purity of the product prepared by the method of this invention meets the application requirements of organic photovoltaics (OPV), organic field-effect transistors (OFETs) and organic light-emitting diodes (OLEDs). The invention has the characteristics of safe and controllable operation, high raw material utilization rate and suitability for industrial scale-up, which effectively fills the gap in the large-scale supply of high-purity conjugated thiophene intermediates. Attached Figure Description

[0036] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0037] Figure 1 This is a schematic diagram of the structure of the 20L four-necked reaction flask used in the embodiment of the present invention, wherein 1-constant temperature bath circulation tank, 2-four-necked reaction vessel, 3-precision thermometer, 4-paddle magnetic stirrer, 5-constant pressure dropping funnel, and 6-liquid nitrogen;

[0038] Figure 2 The 1H NMR spectrum, 1C NMR spectrum, and MALDI-TOF-MS spectra of 1,3-bis(thiophen-2-yl)-5,7-bis(2-ethylhexyl)benzo[1,2-c:4,5-c]dithiophene-4,8-dione prepared in Example 1 (from top to bottom).

[0039] Figure 3 The 1H NMR spectrum, 1C NMR spectrum, and MALDI-TOF-MS spectrum of 3,3'-bis(2,4,6-triisopropylphenyl)-2,2'-bidithiophene prepared in Example 2 (from top to bottom);

[0040] Figure 4 The 1H NMR spectrum, 1C NMR spectrum, and MALDI-TOF-MS spectrum of 2,5-bis(thiophen-2-yl) terephthalate prepared in Example 3 (from top to bottom);

[0041] Figure 5The 1H NMR spectrum, 1C NMR spectrum, and MALDI-TOF-MS spectra of 3,3'-bis(2,4,6-trimethylphenyl)-2,2'-bidithiophene prepared in Example 4 (from top to bottom);

[0042] Figure 6 The 1H NMR spectrum, 1C NMR spectrum, and EI-MS spectrum of benzo[1,2-B:4,5-B']dithiophene-4,8-dione prepared in Example 5 (from top to bottom).

[0043] Figure 7 The 1H NMR spectrum, 1C NMR spectrum, and MALDI-TOF-MS spectra of 4,8-di-(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-B:4,5-B']dithiophene prepared in Example 6 (from top to bottom);

[0044] Figure 8 The 1H NMR spectrum, 1C NMR spectrum, and MALDI-TOF-MS spectra of 4,4,9,9-tetra(4-hexylphenyl)-4,9-dihydro-s-benzodiindo[1,2-b:5,6-b']dithiophene prepared in Example 7 (from top to bottom);

[0045] Figure 9 The 1H NMR spectrum, 1C NMR spectrum, and MALDI-TOF-MS spectra of 4,4,9,9-tetra(dodecyl)-4,9-dihydro-s-indarsenop[1,2-b:5,6-b']dithiophene prepared in Example 8 (from top to bottom);

[0046] Figure 10 The 1H NMR spectrum, 1C NMR spectrum, and MALDI-TOF-MS spectra of 4,4,9,9-tetrahexyl-4,9-dihydro-s-indazanop-[1,2-b:5,6-b0]dithiophene prepared in Example 9 are shown in the following figures (from top to bottom).

[0047] Figure 11 The 1H NMR, 1C NMR, and EI-MS spectra of 3-undecylthiophene[3,2-b]thiophene-2-carboxylic acid prepared in Example 10 (from top to bottom);

[0048] Figure 12 The 1H NMR spectrum, 1C NMR spectrum, and EI-MS spectrum of 3-nonylthiophene[3,2-b]thiophene-2-carboxylic acid prepared in Example 11 (from top to bottom);

[0049] Figure 13 The 1H NMR spectrum, 1C NMR spectrum, and EI-MS spectrum of thiopheno[3,2-b]thiophene prepared in Example 12 (from top to bottom). Detailed Implementation

[0050] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0051] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0052] The kilogram-scale preparation method of conjugated thiophene-based organic photoelectric intermediates proposed in this invention is applicable to benzo[1,2-B:4,5-B']dithiophene-4,8-dione, 4,8-di-(5-(2-ethylhexyl)thiophene-2-yl)benzo[1,2-B:4,5-B']dithiophene, 1,3-bis(thiophene-2-yl)-5,7-bis(2-ethylhexyl)benzo[1,2-c:4,5-c']dithiophene-4,8-dione, 3,3'-bis-(2,4,6-triisopropylphenyl)-2,2'-bithiophene, 4,4,9,9-tetra(dodecyl)-4,9-dihydro-s-indarsen[1 Preparation of 2,5-bis(thiophen-2-yl) terephthalate, 4,4,9,9-tetra(4-hexylphenyl)-4,9-dihydro-s-benzodiindo[1,2-b:5,6-b']dithiophene, 3,3'-bis(2,4,6-trimethylphenyl)-2,2'-bidithiophene, thiophene[3,2-b] thiophene, 3-undecylthiophene[3,2-b] thiophene-2-carboxylic acid, 3-nonylthiophene[3,2-b] thiophene-2-carboxylic acid or 4,4,9,9-tetrahexyl-4,9-dihydro-s-indargenop-[1,2-b:5,6-b0]dithiophene. Specifically, the method for preparing a kilogram-scale conjugated thiophene-based organic photoelectric intermediate reagent in this embodiment of the invention includes the following steps (Method 1):

[0053] Thiophene derivative raw material, electrophilic reagent, and N,N-dimethylformamide (DMF) were added to a reaction flask at room temperature and stirred. A catalyst was added under a nitrogen atmosphere to catalyze the reaction. Thin-layer chromatography was used to monitor the reaction. After the reaction was completed, N,N-dimethylformamide was evaporated. Then, dichloromethane and water were added, and the mixture was stirred and allowed to stand for phase separation. After the aqueous phase was released, water was added again and stirred for phase separation. The remaining organic phase was released. All aqueous phases were collected and extracted with dichloromethane, and the organic phase was collected. The organic phases were combined, and anhydrous magnesium sulfate was added and stirred to dry and remove water. The magnesium sulfate solid was removed by vacuum filtration using a ceramic Buchner funnel and a vacuum flask. The filtrate was collected and concentrated under reduced pressure using a rotary evaporator. The filtrate was then preliminarily purified by column chromatography to obtain a conjugated thiophene organic photoelectric intermediate reagent.

[0054] In a preferred embodiment of the present invention, the electrophilic reagent is 2-(2-ethylhexyl)thiophene, 2-tributylmethyltinylthiophene, or 2,4,6-isopropylphenylboronic acid.

[0055] In a preferred embodiment of the present invention, the molar ratio of the electrophilic reagent to the dried thiophene derivative raw material is 2.1:1-2.5:1.

[0056] In a preferred embodiment of the present invention, the catalyst is tetra(triphenylphosphine)palladium (0) or [(1,2,4,5-η)-1,5-diphenyl-1,4-pentadien-3-one]palladium; when the catalyst is [(1,2,4,5-η)-1,5-diphenyl-1,4-pentadien-3-one]palladium, the step of adding tris(o-methylphenyl)phosphine is further included, and the molar ratio of [(1,2,4,5-η)-1,5-diphenyl-1,4-pentadien-3-one]palladium to tris(o-methylphenyl)phosphine is 1:6.

[0057] In a preferred embodiment of the present invention, the amount of catalyst used is 0.1%-1% of the molar amount of the thiophene derivative raw material.

[0058] In a preferred embodiment of the present invention, the temperature of the catalytic reaction is 85-110°C.

[0059] In addition, this invention also proposes several other methods for preparing kilogram-scale conjugated thiophene-based organic photoelectric intermediates, method two:

[0060] Tetrahydrofuran (THF) was poured into a reaction flask, and thiophene derivative raw material was added and stirred at room temperature. Under nitrogen protection, the mixture was cooled down, and then alkyl lithium reagent was slowly added dropwise. After the addition was complete, the mixture was allowed to cool naturally to room temperature and stirred continuously at room temperature. Then, the mixture was cooled down and water was slowly added dropwise. After the water was added, the mixture was stirred continuously at room temperature. The liquid was then removed by vacuum filtration using a ceramic Buchner funnel and a vacuum flask. The filter cake was collected and recrystallized using toluene as a solvent to obtain a conjugated thiophene organic photoelectric intermediate reagent.

[0061] In the above preparation method, the alkyllithium reagent is a tetrahydrofuran solution of n-butyllithium or a n-hexane solution of tert-butyllithium; the concentration of the alkyllithium reagent is 2.0-2.5 mol / L.

[0062] Method 3:

[0063] At room temperature, add thiophene derivative raw material, potassium tert-butoxide (C4H9OK), and dimethyl sulfoxide (DMSO), start stirring, and then add 1-bromododecane (C 12 H 25The reaction was monitored by thin-layer chromatography using petroleum ether as the developing solvent. After the reaction was completed, water was added and stirring was continued, resulting in the precipitation of a large amount of solid. The mixture was filtered under reduced pressure using a ceramic Buchner funnel and a vacuum flask. The filter cake was washed with water, and the filtrate was extracted with petroleum ether. The organic phase was collected and evaporated to dryness to obtain a deep yellow solid. This solid was combined with the filter cake and purified by column chromatography to obtain a conjugated thiophene organic photoelectric intermediate reagent.

[0064] Method 4:

[0065] Ethanol (CH3CH2OH) and potassium hydroxide (KOH) were added to a reaction flask at room temperature. After cooling, the thiophene derivative raw material was slowly added dropwise. After the addition was complete, the temperature was raised to monitor the reaction. Petroleum ether was used as the developing solvent. After the reaction was complete, water was slowly added dropwise and stirring was continued. Then, the ethanol was heated and distilled off. Water was then added back in and stirred. The filtrate was removed by vacuum filtration using a ceramic Buchner funnel and a vacuum flask to obtain a conjugated thiophene organic photoelectric intermediate reagent.

[0066] Method 5:

[0067] Thiophene derivative raw material, copper powder, and quinoline were added at room temperature, and the mixture was stirred. The reaction was monitored by thin-layer chromatography with dichloromethane as the developing solvent. After the reaction was completed, the mixture was cooled to room temperature, and dichloromethane and water were added. The mixture was stirred and allowed to stand for phase separation. The lower organic phase was collected, and water was added to it. The mixture was stirred and allowed to separate phases. The lower organic phase was collected, and anhydrous magnesium sulfate was added and dried to remove water. The magnesium sulfate solid was removed by vacuum filtration using a ceramic Buchner funnel and a vacuum flask. The filtrate was collected and concentrated under reduced pressure using a rotary evaporator to obtain a brownish-gray solid. The solid was preliminarily purified by column chromatography to obtain a conjugated thiophene organic photoelectric intermediate reagent.

[0068] The conjugated thiophene organic photoelectric intermediate reagent prepared by the method of this invention has a single yield of 1-2 kg, a crude product yield of 70%-98%, and a purified product purity of ≥99%.

[0069] The thiophene derivative raw materials used in the embodiments of the present invention need to be dried under nitrogen protection. The drying method is vacuum drying or molecular sieve drying. The vacuum drying temperature is 40-60℃, the vacuum degree is ≤-0.08MPa, and the drying time is 4-8 hours. The moisture content of the raw materials needs to be controlled to be ≤0.05%.

[0070] The reaction flasks used in the embodiments of this invention are selected from 20L four-necked reaction flasks, 20L three-necked reaction flasks, or 20L double-jacketed glass reactors. Taking a 20L four-necked reaction flask as an example, its structural schematic diagram is shown below. Figure 1 Among them, 1-constant temperature bath circulation tank, 2-four-port reaction vessel, 3-precision thermometer, 4-paddle magnetic stirrer, 5-constant pressure dropping funnel, and 6-liquid nitrogen.

[0071] In this embodiment of the invention, room temperature refers to "25±3℃".

[0072] All reagents and raw materials used in the embodiments of this invention were purchased commercially.

[0073] The technical solution of the present invention will be further illustrated by the following embodiments.

[0074] Method 1 was used to prepare kilogram-scale conjugated thiophene-based organic photoelectric intermediates:

[0075] Example 1

[0076] The preparation of 1,3-bis(thiophen-2-yl)-5,7-bis(2-ethylhexyl)benzo[1,2-c:4,5-c']dithiophene-4,8-dione was carried out via the following reaction route:

[0077] ;

[0078] Specifically, the following steps are included:

[0079] At room temperature, 1205 g (2.0 mol) of 1,3-dibromo-5,7-bis(2-ethylhexyl)benzo[1,2-c:4,5-c']dithiophene-4,8-dione, 1866.0 g (5.0 mol) of 2-tributylmethyltinylthiophene and 5 L of N,N-dimethylformamide were added to a 20 L four-necked reaction flask and stirred at 260 rpm. A high-purity nitrogen cylinder was used to purge the reaction flask with nitrogen as a protective condition. After thorough stirring and continuous purging for 10 minutes, 18.31 g (0.02 mol) of [(1,2,4,5-η)-1,5-diphenyl-1,4-pentadien-3-one]palladium and 36.53 g (0.12 mol) of tris(o-methylphenyl)phosphine were added while maintaining positive pressure inside the flask. The feeding funnel and reaction flask walls were then cleaned with 2 L of N,N-dimethylformamide. The condenser was turned on and the refrigeration unit was circulated. The constant temperature bath was turned on and the circulation temperature was set to 100℃, while the internal temperature of the reaction was controlled above 85℃. The reaction was monitored every 2 hours using thin-layer chromatography with petroleum ether and dichloromethane in a volume ratio of 3:1 as the developing solvent. The reaction was stopped after 24 hours when no raw material remained. Connect the water pump to the reaction flask, evaporate 5L of N,N-dimethylformamide, turn off the heating switch of the constant temperature bath, and wait for the temperature inside the reaction flask to drop to room temperature. Add 3L of dichloromethane and 5L of water, continue stirring for 10 minutes, and let it stand to separate the phases. After releasing the aqueous phase, add 2L of water and stir to separate the phases twice more. Release the remaining organic phase. Collect all the aqueous phases and extract them once with 1L of dichloromethane. Collect the organic phases. Combine the organic phases, add 800g of anhydrous magnesium sulfate, stir for 30 minutes to dry and remove water. Use a 15cm diameter ceramic Buchner funnel and a 10L vacuum filtration flask to filter out the magnesium sulfate solid under reduced pressure. Collect the filtrate and concentrate it under reduced pressure using a rotary evaporator to obtain a pale yellow solid. A 15 cm diameter chromatography column was used, with 200 mesh silica gel of 50 cm effective height as packing material and petroleum ether as eluent. The target compound, 1,3-bis(thiophen-2-yl)-5,7-bis(2-ethylhexyl)benzo[1,2-c:4,5-c]dithiophene-4,8-dione, was initially purified by column chromatography with a yield of 93%, and was obtained as a dark yellow solid.

[0080] The 1,3-bis(thiophen-2-yl)-5,7-bis(2-ethylhexyl)benzo[1,2-c:4,5-c]dithiophene-4,8-dione prepared in Example 1 had a purity of 99%. The 1H NMR, 1C NMR, and MALDI-TOF-MS spectra (from top to bottom) are shown below. Figure 2 .

[0081] Example 2

[0082] The preparation of 3,3'-bis-(2,4,6-triisopropylphenyl)-2,2'-bithiophene follows the reaction route:

[0083]

[0084] Specifically, the following steps are included:

[0085] At room temperature, 1537.6 g (6.2 mol) of 2,4,6-isopropylphenylboronic acid, 978.0 g (3.0 mol) of 3,3'-dibromo-2,2'-bithiophene, and 4 L of N,N-dimethylformamide were added to the reaction flask. Stirring was started at 260 rpm. A high-purity nitrogen cylinder was used to purge the reaction flask with nitrogen as a protective condition. After thorough stirring and continuous purging for 10 minutes, 34.65 g (0.03 mol) of tetrakis(triphenylphosphine)palladium(O) was added while maintaining positive pressure inside the reaction flask. The feeding funnel and reaction flask walls were then cleaned with 2 L of N,N-dimethylformamide. The condenser was turned on and the condenser was circulated. The constant temperature bath was turned on, and the circulation temperature was set to 130°C, maintaining the internal reaction temperature above 110°C. The reaction was monitored every 2 hours using thin-layer chromatography with petroleum ether and dichloromethane in a volume ratio of 2:1 as the developing solvent. The reaction was stopped after 24 hours when no raw material remained. A water pump was connected to the reaction flask, and 2 L of N,N-dimethylformamide was evaporated. The heating switch of the thermostatic bath was turned off. Once the temperature inside the reaction flask had cooled to room temperature, 3 L of dichloromethane and 5 L of water were added, and stirring was continued for 10 minutes. The mixture was then allowed to stand for phase separation. After the aqueous phase was discharged, another 2 L of water was added, and the mixture was stirred and separated twice more. The remaining organic phase was discharged, and 800 g of anhydrous magnesium sulfate was added and stirred for 30 minutes to dry. The solution was then filtered under reduced pressure using a 15 cm diameter ceramic Buchner funnel and a 10 L vacuum filtration flask to remove the magnesium sulfate solid. The filtrate was collected and concentrated under reduced pressure using a rotary evaporator to obtain a pale yellow solid. A 15cm diameter chromatography column was used, with 200-mesh silica gel of 50cm effective height as packing material and petroleum ether as eluent. The target compound 3,3'-bis(2,4,6-triisopropylphenyl)-2,2'-bidithiophene 1392g was obtained by column chromatography with a crude yield of 81%.

[0086] The 3,3'-bis(2,4,6-triisopropylphenyl)-2,2'-bidithiophene prepared in Example 2 had a purity of 99%. The 1H NMR, 1C NMR, and MALDI-TOF-MS spectra (from top to bottom) are shown below. Figure 3 .

[0087] Example 3

[0088] The preparation of ethyl 2,5-bis(thiophen-2-yl)terephthalate follows the reaction route below:

[0089]

[0090] Specifically, the following steps are included:

[0091] At room temperature, add 1900g (5.0mol) of diethyl 2,5-dibromoterephthalate, 1664g (13.0mol) of 2-thiopheneboronic acid, 8L of N,N-dimethylformamide (DMF), 800mL of water, and 2.76kg (20mol) of potassium carbonate to the reaction flask. Start stirring at 260rpm. Use a high-purity nitrogen cylinder to purge nitrogen into the reaction flask as a protective condition. After stirring thoroughly and continuously purging for 10 minutes, under the condition of maintaining positive pressure in the reaction flask, add 45.78g (0.05mol) of [(1,2,4,5-η)-1,5-diphenyl-1,4-pentadien-3-one]palladium and 91.33g (0.30mol) of tris(o-methylphenyl)phosphine. Then clean the feeding funnel and the reaction flask wall with 0.5L of DMF, and turn on the condenser and circulate the condenser. After continuous aeration for 10 minutes, the nitrogen valve was closed, and the constant temperature bath circulation tank was opened, setting the circulation temperature to 50℃. When the external temperature exceeded 45℃, the reaction initiated and continued to release heat, causing the internal temperature of the reaction to reach a maximum of 95℃, at which point a large amount of carbon dioxide gas was released. The reaction was monitored every 20 minutes using thin-layer chromatography with petroleum ether and dichloromethane at a volume ratio of 2:1 as the developing solvent. After 24 hours, no raw material remained. The constant temperature bath temperature was set to 90℃, the water pump was connected to the reaction vessel, 4 L DMF was evaporated, the heating switch of the constant temperature bath was turned off, 10 L of water was added, and after the temperature inside the reaction flask dropped to room temperature, 5 L DMF was added. L of dichloromethane was added, and the mixture was stirred for 10 minutes. The mixture was allowed to stand for phase separation. The organic phase was then released, and 2L of dichloromethane was added for extraction once more. The organic phases were combined and added to a reaction vessel. The mixture was extracted twice with 5L of water to remove a large amount of potassium carbonate. The remaining organic phase was released, and 800g of anhydrous magnesium sulfate was added. The mixture was stirred for 30 minutes and dried to remove water. The magnesium sulfate solid was removed by vacuum filtration using a 15cm diameter ceramic Buchner funnel and a 20L vacuum filtration flask. The filtrate was collected and concentrated under reduced pressure using a rotary evaporator to obtain a gray-black solid. A 15cm diameter chromatography column was used, packed with 100-200 mesh silica gel with an effective height of 50cm, and eluent was used. Preliminary purification was performed by column chromatography, yielding 1980.7g of the target compound, 2,5-di(thiophene-2-yl) ethyl terephthalate, in a yellow solid with a crude yield of 98%.

[0092] The ethyl 2,5-bis(thiophene-2-yl) terephthalate prepared in Example 3 had a purity of 99%. The 1H NMR, 1C NMR, and MALDI-TOF-MS spectra (from top to bottom) are shown below. Figure 4 .

[0093] Example 4

[0094] The preparation of 3,3'-bis(2,4,6-trimethylphenyl)-2,2'-bidithiophene follows the reaction route below:

[0095]

[0096] Specifically, the following steps are included:

[0097] At room temperature, 1344.8 g (8.2 mol) of 2,4,6-methylphenylboronic acid, 1304.0 g (4.0 mol) of 3,3'-dibromo-2,2'-bithiophene, and 5 L of N,N-dimethylformamide were added to a reaction flask. Stirring was started at 260 rpm. A high-purity nitrogen cylinder was used to purge the reaction flask with nitrogen as a protective condition. After thorough stirring and continuous purging for 10 minutes, 46.2 g (0.04 mol) of tetrakis(triphenylphosphine)palladium(O) was added while maintaining positive pressure inside the reaction flask. The feeding funnel and reaction flask walls were then cleaned with 2 L of N,N-dimethylformamide. The condenser was turned on and the condenser was circulated. The constant temperature bath was turned on, and the circulation temperature was set to 130°C, maintaining the internal reaction temperature above 110°C. The reaction was monitored every 2 hours using thin-layer chromatography with petroleum ether and dichloromethane in a volume ratio of 2:1 as the developing solvent. The reaction was stopped after 24 hours when no raw material remained. A water pump was connected to the reaction flask, and 3 L of N,N-dimethylformamide was evaporated. The heating switch of the thermostatic bath was turned off. Once the temperature inside the reaction flask had cooled to room temperature, 3 L of dichloromethane and 5 L of water were added, and stirring was continued for 10 minutes. The mixture was then allowed to stand for phase separation. After the aqueous phase was discharged, another 2 L of water was added, and the mixture was stirred and separated twice more. The remaining organic phase was discharged, and 800 g of anhydrous magnesium sulfate was added and stirred for 30 minutes to dry. The solution was then filtered under reduced pressure using a 15 cm diameter ceramic Buchner funnel and a 10 L vacuum filtration flask to remove the magnesium sulfate solid. The filtrate was collected and concentrated under reduced pressure using a rotary evaporator to obtain a pale yellow solid. A 15cm diameter chromatography column was used, with 200-mesh silica gel of 50cm effective height as the packing material and petroleum ether as the eluent. The target compound 3,3'-bis(2,4,6-trimethylphenyl)-2,2'-bidithiophene 1463.3g was obtained by column chromatography with a crude yield of 91%.

[0098] The 3,3'-bis(2,4,6-trimethylphenyl)-2,2'-bidithiophene prepared in Example 4 had a purity of 99%. The 1H NMR, 1C NMR, and MALDI-TOF-MS spectra (from top to bottom) are shown below. Figure 5 .

[0099] Method 2 was used to prepare kilogram-scale conjugated thiophene-based organic photoelectric intermediates:

[0100] Example 5

[0101] The preparation of benzo[1,2-B:4,5-B']dithiophene-4,8-dione follows the reaction route as follows:

[0102]

[0103] Specifically, the following steps are included:

[0104] Pour 2L of tetrahydrofuran (THF) into the reaction flask at room temperature, start stirring at 150rpm, and add 3660g (20.0mol) of thiophene-3-(N,N-diethyl)formamide. Use a high-purity nitrogen cylinder to purge the reaction flask with nitrogen for ten minutes as a protective condition, and connect a balloon to ensure that the system is under positive pressure with nitrogen atmosphere. Add liquid nitrogen in batches to the cold bath device, and use the liquid nitrogen-ethanol cold bath system to cool the temperature inside the reaction flask to below -78℃. Observe the temperature change inside the reaction flask at all times to ensure that the temperature inside the reaction flask does not exceed -78℃. Slowly add 8.2 L (20.5 mol) of a 2.5 M tetrahydrofuran solution of n-butyllithium, controlling the dropping rate and constantly monitoring the temperature to ensure it does not exceed -40°C. The addition of the tetrahydrofuran solution of n-butyllithium takes 3 hours. After the addition is complete, maintain the reaction system temperature between -30°C and 0°C. After 3 hours, allow the system to return to room temperature naturally and stir continuously at room temperature for 12 hours. Add liquid nitrogen to the cold bath to bring the temperature inside the reaction flask below 0°C. Slowly add 2.0 L of water, controlling the dropping rate and monitoring the temperature. During the addition, ensure the system temperature does not exceed 0°C. After the water is complete, stir continuously at room temperature for 6 hours. The liquid was removed by vacuum filtration using a 25cm diameter ceramic Buchner funnel and a 20L suction flask. The filter cake was collected and recrystallized using toluene as a solvent. 1936g of the target product, benzo[1,2-B:4,5-B']dithiophene-4,8-dione, was obtained in crude yield of 88%, and it was a light yellow solid.

[0105] The benzo[1,2-B:4,5-B']dithiophene-4,8-dione prepared in Example 5 had a purity of 98%. The 1H NMR, 1C NMR, and EI-MS spectra (from top to bottom) are shown below. Figure 6 .

[0106] Example 6

[0107] The preparation of 4,8-di-(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-B:4,5-B']dithiophene follows the reaction route:

[0108]

[0109] Specifically, the following steps are included:

[0110] At room temperature, 928.3 g (4.0 mol) of 2-(2-ethylhexyl)thiophene and 2 L of tetrahydrofuran were added to a reaction flask, and stirring was started at 260 rpm. A high-purity nitrogen cylinder was used to purge the reaction flask with nitrogen as a protective condition. Liquid nitrogen was added to a cold bath containing ethanol to cool the reaction flask, maintaining the temperature inside the flask no higher than -78°C. After thorough stirring and continuous aeration for 10 minutes, 1.76 L of 2.5 M tetrahydrofuran (4.4 mol) of n-butyllithium was added to a constant-pressure dropping funnel. The valve of the constant-pressure dropping funnel was opened, and the tetrahydrofuran of n-butyllithium was slowly added dropwise to the system. During the addition, the temperature of the reaction system was controlled to be no higher than -60°C. After the addition was completed, stirring was continued for 2 hours while maintaining the temperature inside the reaction flask between -60°C and -40°C. Dissolve 440.55 g (2.0 mol) of benzo[1,2-B:4,5-B']dithiophene-4,8-dione thoroughly in 1 L of tetrahydrofuran and add the solution to a constant-pressure dropping funnel. Add liquid nitrogen to lower the temperature inside the reaction flask to -78°C. Open the valve of the constant-pressure dropping funnel and slowly add the tetrahydrofuran solution of benzo[1,2-B:4,5-B']dithiophene-4,8-dione to the system. During the addition, control the temperature of the reaction system to not exceed -60°C. After the addition is complete, do not add more liquid nitrogen. Allow the reaction system to naturally warm to room temperature and continue stirring overnight. Remove the reaction flask from the cold bath, install a condenser, and place the reaction flask in a constant-temperature circulating bath. Dissolve 542.0 g (2.4 mol) of tin dichloride dihydrate in 1200 mL of 10 wt.% dilute hydrochloric acid. After thorough stirring, add the solution to a constant pressure dropping funnel. Open the valve of the constant pressure dropping funnel and slowly add the tin dichloride dihydrate solution to the system. After the addition is complete, turn on the condenser and circulate the condenser. Set the circulation temperature of the constant temperature bath to 65°C and control the temperature of the system in the reaction flask to above 50°C. Continue stirring for 1 hour. Turn off the heating switch of the constant temperature bath circulation tank. After the temperature inside the vessel drops to room temperature, add 3.6 L of ethyl acetate to the reaction flask, stir for 10 minutes, and allow to stand for phase separation. After releasing the lower aqueous phase, add 5 L of water and stir repeatedly for phase separation twice. Release the remaining organic phase, add 800 g of anhydrous magnesium sulfate, stir for 30 minutes to dry and remove water. Use a 15 cm diameter ceramic Buchner funnel and a 10 L vacuum filtration flask to filter out the magnesium sulfate solid under reduced pressure. Collect the filtrate and concentrate it under reduced pressure using a rotary evaporator to obtain a brown solid. Take a 15 cm diameter chromatography column, use 200 mesh silica gel with an effective height of 50 cm as the packing material, and use petroleum ether as the eluent. Perform preliminary purification by column chromatography to obtain 1080 g of the target product 4,8-di-(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-B:4,5-B']dithiophene in a crude yield of 82%.

[0111] The 4,8-di-(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-B:4,5-B']dithiophene prepared in Example 6 had a purity of 98%. The 1H NMR, 1C NMR, and MALDI-TOF-MS spectra (from top to bottom) are shown below. Figure 7 .

[0112] Example 7

[0113] The preparation of 4,4,9,9-tetra(4-hexylphenyl)-4,9-dihydro-s-benzodiindrone[1,2-b:5,6-b']dithiophene is shown by the following reaction equation:

[0114]

[0115] Specifically, the following steps are included:

[0116] Place the reaction flask in an ethanol cold bath at room temperature, pour in 3 L of tetrahydrofuran, start stirring at 260 rpm, add 2120.8 (8.8 mol) of 4-bromohexylbenzene, and stir until the raw materials are fully dissolved. Use a high-purity nitrogen cylinder to purge nitrogen into the reaction vessel for ten minutes as a protective condition, and connect a balloon to ensure that the system is under positive pressure with nitrogen atmosphere. Slowly add liquid nitrogen to the ethanol cold bath device, and start adding materials after the temperature inside the reaction flask has cooled to below -40 ℃. 3.6 L (9.0 mol) of a 2.5 M n-butyllithium tetrahydrofuran solution was slowly added dropwise to the reaction flask using a constant-pressure dropping funnel. The dropping rate was controlled during the addition, and the temperature was constantly monitored to ensure it did not exceed -30°C. The entire process of adding the n-butyllithium tetrahydrofuran solution took 2 hours. After the addition was complete, the feeding device was rinsed with 300 mL of tetrahydrofuran. The constant-temperature bath was set at -30°C, and the reaction system was kept at -40°C to -30°C for two hours. Then, 772.0 g (2.0 mol) of [a specific ingredient] was slowly added dropwise through a separatory funnel. A tetrahydrofuran solution of diethyl 2,5-bis(thiophene-2-yl) terephthalate (1000 mL total) was added. The dropping rate was controlled and the temperature was monitored. During the dropping process, the temperature of the system was kept below 0°C. After the tetrahydrofuran solution of diethyl 2,5-bis(thiophene-2-yl) terephthalate was completely added, the system was kept at an internal temperature below 0°C for 4 hours. The reaction progress was monitored by TLC using petroleum ether:dichloromethane = 5:1 as the developing solvent. After no raw materials or reaction intermediates remained, 3 L of water was slowly added, and the system was gradually brought back to room temperature. Then, 4 L of water was added, and a large amount of white solid precipitated. The solid was filtered under reduced pressure using a 15 cm diameter ceramic Buchner funnel and a 10 L vacuum filtration flask to obtain a filter cake. The filtrate was extracted once with 3 L of dichloromethane and collected separately. The obtained filter cake was dried and added to a 20L reaction flask equipped with a mechanical stirrer. The reaction flask was placed in an oil bath, 5L of glacial acetic acid was added, and 3ml of concentrated sulfuric acid was slowly added dropwise. The temperature was raised to 110℃ and the reaction was carried out for 3 hours. The reaction was monitored by thin-layer chromatography with petroleum ether as the developing solvent. The reaction was stopped when no intermediate remained. After the reaction solution was cooled to room temperature, it was poured into a 20L LPP container containing 10L of water. The solution was filtered under reduced pressure using a 130cm diameter ceramic Buchner funnel and a 20L vacuum filtration flask. The solid was washed five times with 1L of water. The obtained solid was dried and 1576g of the target product 4,4,9,9-tetra(4-hexylphenyl)-4,9-dihydro-s-benzodiindo[1,2-b:5,6-b']dithiophene was obtained with a crude yield of about 87%. The product was a brownish-yellow solid.

[0117] The 4,4,9,9-tetra(4-hexylphenyl)-4,9-dihydro-s-benzodiindrone[1,2-b:5,6-b']dithiophene prepared in Example 7 had a purity of 98%. The 1H NMR, 1C NMR, and MALDI-TOF-MS spectra (from top to bottom) are shown below. Figure 8 .

[0118] Method 3 was used to prepare kilogram-scale conjugated thiophene-based organic photoelectric intermediates:

[0119] Example 8

[0120] The preparation of 4,4,9,9-tetra(dodecyl)-4,9-dihydro-s-indarseno[1,2-b:5,6-b']dithiophene follows the following reaction route:

[0121]

[0122] The specific preparation method is as follows:

[0123] At room temperature, add 532.0 g (2.0 mol) of 4,9-dihydro-s-indargeno[1,2-b:5,6-b']dithiophene, 600 g of potassium tert-butoxide (C4H9OK), and 10 L of dimethyl sulfoxide to a reaction flask. Start the stirrer at 200 rpm, purge the reaction apparatus with nitrogen for 10 minutes, and connect a balloon to maintain a positive pressure inert atmosphere within the system. 2116 g (8.5 mol) of 1-bromododecane was added to a constant-pressure dropping funnel. The reaction was monitored by thin-layer chromatography with petroleum ether as the developing solvent every 2 hours. After 12 hours, when no raw material remained, the reaction was stopped. 5 L of water was slowly added to the reaction flask, and stirring was continued for 20 minutes. A large amount of solid precipitated out. The mixture was filtered under reduced pressure using a 15 cm diameter ceramic Buchner funnel and a 10 L vacuum filtration flask. The filter cake was washed three times with 1 L of water and collected. The filtrate was extracted twice with 2 L of petroleum ether, and the organic phase was collected and evaporated to dryness to obtain a deep yellow solid, which was combined with the filter cake. A 15 cm diameter chromatography column was used, with 200 mesh silica gel of 70 cm effective height as packing material and petroleum ether as eluent. The target compound 4,4,9,9-tetra(dodecyl)-4,9-dihydro-s-indarafeno[1,2-b:5,6-b']dithiophene 1313.2 g was obtained in crude yield of 70%, which was a viscous brown liquid.

[0124] The 4,4,9,9-tetra(dodecyl)-4,9-dihydro-s-indarsen[1,2-b:5,6-b']dithiophene prepared in Example 8 had a purity of 98%. The 1H NMR, 1C NMR, and MALDI-TOF-MS spectra (from top to bottom) are shown below. Figure 9 .

[0125] Example 9

[0126] The preparation of 4,4,9,9-tetrahexyl-4,9-dihydro-s-indarsen-[1,2-b:5,6-b0]dithiophene follows the following reaction route:

[0127]

[0128] The specific preparation method is as follows:

[0129] At room temperature, add 532.76 g (2 mol) of 4,9-dihydro-S-benzodiindrone[1,2-b:5,6-b']dithiophene, 1346.52 g (12 mol) of potassium tert-butoxide, and 5 L of dimethyl sulfoxide to the reaction flask, and start stirring at 260 rpm. Add 1485.63 g (4.5 mol) of 1-bromohexane to the constant pressure dropping funnel. While controlling the internal temperature of the reaction flask to not exceed 20°C, add 1-bromohexane dropwise to the reaction flask. After the addition was complete, the reaction was monitored every 2 hours using thin-layer chromatography with dichloromethane:petroleum ether = 1:1 as the developing solvent. After 10 hours, when no raw material remained, the reaction was stopped, 5 L of petroleum ether and 2 L of water were added, stirred for 10 minutes, and allowed to stand for phase separation. After the lower aqueous phase was released, 5 L of water was added again, and the phases were separated twice by stirring. The organic phase was collected, and 800 g of anhydrous magnesium sulfate was added and stirred for 30 minutes to dry and remove water. The magnesium sulfate solid was removed by vacuum filtration using a 15 cm diameter ceramic Buchner funnel and a 10 L vacuum flask. The filtrate was collected and concentrated under reduced pressure using a rotary evaporator to obtain a dark oily liquid. A 15cm diameter chromatography column was used, with 200-mesh silica gel of 50cm effective height as the packing material, and petroleum ether: dichloromethane = 5:1 as the eluent. The product 4,4,9,9-tetrahexyl-4,9-dihydro-s-indaheno-[1,2-b:5,6-b0]dithiophene 1025g was obtained in crude yield of 85%.

[0130] The 4,4,9,9-tetrahexyl-4,9-dihydro-s-indargen-[1,2-b:5,6-b0]dithiophene prepared in Example 9 had a purity of 99%. The 1H NMR, 1C NMR, and MALDI-TOF-MS spectra (from top to bottom) are shown below. Figure 10 .

[0131] Method 4 was used to prepare kilogram-scale conjugated thiophene-based organic photoelectric intermediates:

[0132] Example 10

[0133] The preparation of 3-undecylthiophene[3,2-b]thiophene-2-carboxylic acid follows the reaction route:

[0134]

[0135] The specific preparation method is as follows:

[0136] Add 10 L of ethanol and 400 g of potassium hydroxide to the reaction flask at room temperature. Start the stirrer at 260 rpm. Turn on the condenser and set the circulation temperature to 0 °C, controlling the internal reaction temperature below 10 °C. Slowly add 3240 g (8.85 mol) of ethyl 3-undecylthiophene[3,2-b]thiophene-2-carboxylate, constantly monitoring the temperature change inside the reaction vessel to ensure it does not exceed 10 °C. The addition of ethyl 3-undecylthiophene[3,2-b]thiophene-2-carboxylate takes 3 hours. After the addition is complete, rinse the feeding funnel and reaction flask walls with 500 mL of ethanol. Turn on the constant temperature bath and set the circulation temperature to 90 °C, controlling the internal reaction temperature above 70-75 °C. Monitor the reaction every 2 hours using thin-layer chromatography with petroleum ether as the developing solvent. After 12 hours, no raw material remains. Turn off the heating switch of the thermostatic bath and wait for the temperature inside the reaction flask to drop below 50°C. Slowly add 5L of water and continue stirring for 2 hours. Turn on the thermostatic bath circulation tank and set the circulation temperature to 85°C. Distill off 6L of ethanol. Add another 5L of water and stir. Use a 25cm diameter ceramic Buchner funnel and a 20L vacuum filtration flask to remove the filtrate under reduced pressure, obtaining 2563g of the target product 3-undecylthiophene[3,2-b]thiophene-2-carboxylic acid with a crude yield of 87%, which is a pale yellow solid.

[0137] The 3-undecylthiophene[3,2-b]thiophene-2-carboxylic acid prepared in Example 10 had a purity of 99%. The 1H NMR, 1C NMR, and EI-MS spectra (from top to bottom) are shown below. Figure 11 .

[0138] Example 11

[0139] The preparation of 3-nonylthiophene[3,2-b]-thiophene-2-carboxylic acid follows the reaction route:

[0140]

[0141] The specific preparation method is as follows:

[0142] Add 10L of ethanol and 400g of potassium hydroxide to the reaction flask at room temperature. Start the stirrer at 260rpm. Turn on the condenser and set the circulation temperature to 0℃, controlling the internal reaction temperature below 10℃. Slowly add 2928g (8.0mol) of ethyl 3-nonylthiophene[3,2-b]thiophene-2-carboxylate, constantly monitoring the temperature change inside the reaction vessel to ensure it does not exceed 10℃. The addition of ethyl 3-nonylthiophene[3,2-b]thiophene-2-carboxylate takes 3 hours. After the addition is complete, rinse the feeding funnel and reaction flask walls with 500mL of ethanol. Turn on the constant temperature bath and set the circulation temperature to 90℃, controlling the internal reaction temperature above 70-75℃. The reaction was monitored every 2 hours using thin-layer chromatography with petroleum ether as the developing solvent. After 24 hours, no raw material remained. The heating switch of the thermostatic bath was turned off, and the temperature inside the reaction flask was allowed to drop to room temperature. 5L of water was slowly added dropwise, and stirring was continued for 2 hours. The thermostatic bath circulation tank was turned on, and the circulation temperature was set to 85℃. 6L of ethanol was distilled off. 4L of water was added and stirred. The filtrate was removed by vacuum filtration using a 25cm diameter ceramic Buchner funnel and a 20L vacuum filtration flask. 2399g of the target product, 3-nonylthiophene[3,2-b]thiophene-2-carboxylic acid, was obtained with a crude yield of 94%, as a pale yellow solid.

[0143] The 3-nonylthiophene[3,2-b]thiophene-2-carboxylic acid prepared in Example 11 had a purity of 99%. The 1H NMR, 1C NMR, and EI-MS spectra (from top to bottom) are shown below. Figure 12 .

[0144] Method 5 was used to prepare kilogram-scale conjugated thiophene-based organic photoelectric intermediates:

[0145] Example 12

[0146] The preparation of thiophene[3,2-b]thiophene follows the reaction route:

[0147]

[0148] The specific preparation method is as follows:

[0149] At room temperature, add 1566.04 g (8.5 mol) of thiopheno[3,2-b]thiophene-2-carboxylic acid, 108.8 g (1.7 mol) of copper powder, and 3 L of quinoline to the reaction flask. Start the stirrer at 260 rpm. Turn on the condenser and refrigeration unit, turn on the electric heating mantle, and set the heating temperature of the electric heating mantle to 180°C, controlling the internal temperature of the reaction flask to be above 160°C. The reaction was monitored every 2 hours using thin-layer chromatography with dichloromethane as the developing solvent. After 16 hours, when no raw material remained, the heating switch of the electric heating mantle was turned off, and the reaction was stopped. After the temperature in the reaction flask dropped to room temperature, 3 L of dichloromethane and 2 L of water were added, stirred for 10 minutes, and allowed to stand for phase separation. The lower organic phase was collected, and 5 L of water was added to it. The phase separation was repeated twice with stirring. The lower organic phase was collected, and 800 g of anhydrous magnesium sulfate was added and stirred for 30 minutes to dry and remove water. The magnesium sulfate solid was removed by vacuum filtration using a 15 cm diameter ceramic Buchner funnel and a 10 L vacuum flask. The filtrate was collected and concentrated under reduced pressure using a rotary evaporator to obtain a brownish-gray solid. A 15 cm diameter chromatography column was used with 200 mesh silica gel with an effective height of 50 cm as the packing material and petroleum ether:dichloromethane = 1:1 as the eluent. The product thiophene[3,2-b]thiophene was initially purified by column chromatography with a crude yield of 88% (1049 g).

[0150] The thiopheno[3,2-b]thiophene prepared in Example 12 had a purity of 99%. The 1H NMR, 1C NMR, and EI-MS spectra (from top to bottom) are shown below. Figure 13 .

[0151] The above are merely preferred embodiments 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 scope of the technology 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 conjugated thiophene-based organic photoelectric intermediate reagents at the kilogram scale, characterized in that, Includes the following steps: (1) Load the thiophene derivative raw material into a reaction flask, add the electrophilic reagent and reaction solvent, and start stirring; (2) Under a protective atmosphere, a catalyst is added to the system obtained in step (1) to carry out a catalytic reaction. The reaction is monitored by thin-layer chromatography until no raw material remains. (3) After cooling the catalytic reaction product of step (2), add dichloromethane and water, stir and let stand to separate the phases, collect the organic phase, extract the aqueous phase with dichloromethane and collect the extracted organic phase, and combine all organic phases; (4) The combined organic phase is dried, filtered, concentrated under reduced pressure, and then purified by column chromatography to obtain the conjugated thiophene organic photoelectric intermediate reagent. The weight of the product prepared in one batch is 1-2 kg.

2. The method for preparing the conjugated thiophene-based organic photoelectric intermediate reagent at the kilogram scale according to claim 1, characterized in that, In step (1), the molar ratio of the electrophilic reagent to the thiophene derivative raw material is (2.1-2.5):

1.

3. The method for preparing the conjugated thiophene-based organic photoelectric intermediate reagent at the kilogram scale according to claim 2, characterized in that, In step (1), the electrophilic reagent is 2-(2-ethylhexyl)thiophene, 2-tributylmethyltinylthiophene, or 2,4,6-isopropylphenylboronic acid.

4. The method for preparing the conjugated thiophene-based organic photoelectric intermediate reagent at the kilogram scale according to claim 1, characterized in that, In step (2), the catalyst is tetra(triphenylphosphine)palladium(0) or [(1,2,4,5-η)-1,5-diphenyl-1,4-pentadien-3-one]palladium.

5. The method for preparing the conjugated thiophene-based organic photoelectric intermediate reagent at the kilogram scale according to claim 1, characterized in that, In step (2), when the catalyst is [(1,2,4,5-η)-1,5-diphenyl-1,4-pentadien-3-one]palladium, tris(o-methylphenyl)phosphine is added, and the molar ratio of [(1,2,4,5-η)-1,5-diphenyl-1,4-pentadien-3-one]palladium to tris(o-methylphenyl)phosphine is 1:

6.

6. The method for preparing the conjugated thiophene-based organic photoelectric intermediate reagent at the kilogram scale according to claim 1, characterized in that, In step (2), the amount of catalyst used is 0.1%-1% of the molar amount of the thiophene derivative raw material.

7. The method for preparing the conjugated thiophene-based organic photoelectric intermediate reagent at the kilogram scale according to claim 1, characterized in that, In step (2), the temperature of the catalytic reaction is 85-110℃.

8. The method for preparing the conjugated thiophene-based organic photoelectric intermediate reagent at the kilogram scale according to claim 1, characterized in that, In step (2), the protective atmosphere is a nitrogen atmosphere, and the nitrogen is purged into the reaction system for no less than 10 minutes. The reaction is carried out under positive pressure.

9. The method for preparing the conjugated thiophene-based organic photoelectric intermediate reagent on a kilogram-scale according to claim 1, characterized in that, The conjugated thiophene-based organic photoelectric intermediates include benzo[1,2-B:4,5-B']dithiophene-4,8-dione, 4,8-di-(5-(2-ethylhexyl)thiophene-2-yl)benzo[1,2-B:4,5-B']dithiophene, 1,3-bis(thiophene-2-yl)-5,7-bis(2-ethylhexyl)benzo[1,2-c:4,5-c']dithiophene-4,8-dione, 3,3'-bis-(2,4,6-triisopropylphenyl)-2,2'-bithiophene, and 4,4,9,9-tetra(dodecyl)-4,9-dihydro-s-indargenop[1,2-b:5, [6-b']dithiophene, ethyl 2,5-bis(thiophene-2-yl)terephthalate, 4,4,9,9-tetra(4-hexylphenyl)-4,9-dihydro-s-benzodiindo[1,2-b:5,6-b']dithiophene, 3,3'-bis(2,4,6-trimethylphenyl)-2,2'-bidithiophene, thiophene[3,2-b]thiophene, 3-undecylthiophene[3,2-b]thiophene-2-carboxylic acid, 3-nonylthiophene[3,2-b]thiophene-2-carboxylic acid or 4,4,9,9-tetrahexyl-4,9-dihydro-s-indargenop-[1,2-b:5,6-b0]dithiophene.

10. The method for preparing the conjugated thiophene-based organic photoelectric intermediate reagent on a kilogram-scale according to claim 1, characterized in that, In step (1), the reaction solvent is N,N-dimethylformamide; In step (2), when monitoring the reaction using thin-layer chromatography, the developing solvent is a mixture of petroleum ether and dichloromethane in a volume ratio of 2:1 to 3:1.

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