Efficient and environment-friendly synthesis process of 1-bromo-dibenzofuran

Abstract

The invention discloses an efficient and environment-friendly 1-bromo-dibenzofuran synthesis process, and belongs to the technical field of organic matter synthesis. The method is used for solving the technical problems in the prior art that raw materials for synthesis are toxic and strong in corrosivity, the preparation process is complicated, and the yield and the purity of a product obtained through multiple times of post-treatment are reduced in the process for synthesizing the 1-bromo-dibenzofuran. The invention relates to an efficient and environment-friendly 1-bromo-dibenzofuran synthesis process which comprises the following steps: carrying out Williamson synthesis reaction on 2, 3-dibromo fluorobenzene, phenol, strong alkali and weak acid salt, a solvent and a catalyst A to obtain an intermediate 1; the intermediate 1, alkali, an initiator and a catalyst B are subjected to a ring closing reaction, and 1-bromo-dibenzofuran is synthesized. The 1-bromo-dibenzofuran is prepared by adopting a two-step method, the adopted raw materials are green and environment-friendly, the synthesis process is simplified and efficient, and the obtained product 1-bromo-dibenzofuran is high in yield and high in purity.

Description

Technical Field

[0001] The invention relates to the technical field of organic compound synthesis, and in particular to a highly efficient and environmentally friendly 1-bromo-dibenzofuran synthesis process. Background Art

[0002] Bromo-dibenzofuran is an important organic synthesis intermediate and is widely used in the field of organic optoelectronic materials, especially in blue light-emitting organic light-emitting devices, where it can reduce the driving voltage of the device and improve the luminous efficiency of the device. However, the traditional synthesis method of 1-bromo-dibenzofuran has some limitations, such as the generation of waste gas and wastewater during the reaction, which causes environmental pollution, low total yield, long process route, high cost, high operating risk, and high equipment requirements. The common synthesis route of 1-bromo-dibenzofuran using 2-bromo-6-fluoroiodobenzene as the starting material is:

[0003] This synthetic route uses boron tribromide as a synthetic material. Boron tribromide is a hazardous chemical that has a strong irritating effect on human tissues. Its vapor is highly toxic and corrosive, and it has a great safety hazard. In addition, during the post-treatment process of adding water, boron tribromide is easy to generate boric acid and hydrogen bromide, which will cause certain damage to the equipment. At the same time, the waste gas and waste liquid generated during the reaction are difficult to handle, and the reaction is highly dangerous.

[0004] Patent application CN115947704A discloses a method for preparing 1-bromodibenzofuran, an intermediate of an organic light-emitting material. 1,4-cyclohexanediol is used as a starting material, and an alcohol O-acylation reaction is carried out with an acyl chloride compound to obtain a 4-hydroxycyclohexyl ester compound; the hydrocarbon group of the 4-hydroxycyclohexyl ester compound is first oxidized by 2,2,6,6-tetramethylpiperidinyl oxide to obtain a ketone, and then a chlorination reaction is carried out with trichloroisocyanuric acid to obtain an α,α-dichlorocyclohexanone compound; the α,α-dichlorocyclohexanone compound is reacted with 1,3-cyclohexanedione, dichloromethane and triethylamine to obtain 4-dihydrodibenzo[b,d]furan-1(2H)-one. 4-Dihydrodibenzo[b,d]furan-1(2H)-one is further reacted to finally obtain 1-bromodibenzofuran. Although the raw materials used in the above-mentioned preparation method of 1-bromodibenzofuran are green, environmentally friendly, cheap and easy to obtain; however, the reaction steps are cumbersome and the process is complicated; after multiple post-process treatments, the yield and purity of the product will be significantly reduced. How to develop a green and safe, simplified and efficient, high-purity and high-yield preparation method for the intermediate 1-bromodibenzofuran is a technical problem that needs to be solved urgently.

[0005] In view of the technical defects in this aspect, a solution is now proposed. Summary of the invention

[0006] The purpose of the present invention is to provide an efficient and environmentally friendly 1-bromo-dibenzofuran synthesis process, which is used to solve the technical problems in the prior art that the existing 1-bromo-dibenzofuran synthesis process uses toxic and highly corrosive raw materials, has a complex preparation process, and has a reduced yield and purity of the target product obtained through multiple post-treatment processes.

[0007] The purpose of the present invention can be achieved by the following technical solutions: A highly efficient and environmentally friendly 1-bromo-dibenzofuran synthesis process comprises the following steps: S1, 2,3-dibromofluorobenzene, phenol, a strong base and a weak acid salt, a solvent and a catalyst A are subjected to a Williamson synthesis reaction to obtain a reaction liquid; the reaction liquid is subjected to a post-process treatment to obtain an intermediate 1; S2, intermediate 1, solvent, base, initiator and catalyst B are subjected to a ring-closing reaction to obtain a reaction liquid; the reaction liquid is subjected to a post-process to synthesize 1-bromo-dibenzofuran.

[0008] Furthermore, the synthesis route of the highly efficient and environmentally friendly 1-bromo-dibenzofuran synthesis process is as follows:

[0009] In step S1, 2,3-dibromofluorobenzene is used as a halogenated hydrocarbon in a solvent, and a catalyst A is used to catalyze a reaction. 2,3-dibromofluorobenzene, phenol and a strong base and a weak acid salt undergo a bimolecular nucleophilic substitution reaction to obtain an intermediate 1.

[0010] In step S2, an aprotic solvent is used as a solution, a base is added as a reaction medium, an initiator is used as a reaction aid, and the product 1-bromo-dibenzofuran is finally obtained by catalysis of catalyst B.

[0011] Furthermore, in step S1, the strong base and weak acid salt is any one of sodium carbonate, sodium acetate, sodium hydrosulfide, sodium phosphate, sodium bicarbonate, potassium acetate, potassium hydrogen phosphate or potassium carbonate; and the catalyst A is any one of copper, iodine, cuprous iodide or ferrous chloride.

[0012] Furthermore, in step S1, the Williamson synthesis reaction is carried out under an inert gas atmosphere, and each reaction monomer needs to be heated first, and then the temperature is increased to react; wherein the heating temperature is 50-90°C, and the temperature of the temperature increase reaction is 90-150°C.

[0013] Furthermore, in step S1, the post-processing steps are: extracting the reaction solution with dichloromethane and water, collecting the organic phase; drying and filtering the organic phase to obtain a filtrate; and removing dichloromethane from the filtrate by vacuum rotary evaporation to obtain intermediate 1.

[0014] Furthermore, in step S2, the base includes at least one of sodium tert-butoxide, potassium tert-butoxide, sodium acetate, potassium acetate, sodium ethoxide, lithium hydroxide or potassium hydroxide; before being added, the base must be configured as an aqueous solution of the base, and the concentration of the aqueous solution is 0.1 g / mL-0.5 g / mL.

[0015] Furthermore, in step S2, the catalyst B is any one of palladium acetate, triphenylphosphine palladium or nickel acetate; the initiator is any one of trimethylacetic acid, benzoyl peroxide, ethyl peroxide, sodium periodate or azobisisobutyronitrile.

[0016] Furthermore, in step S2, the ring-closing reaction is carried out under an inert gas atmosphere, and the reaction temperature of the ring-closing reaction is 60-130°C.

[0017] Further, in step S2, the post-processing treatment is: pouring the reaction solution into ice water while hot, letting it stand, and filtering to obtain an upper gray-white solid; pouring the reaction solution into ice water while hot, letting it stand, and filtering to obtain an upper gray-white solid; extracting and filtering the gray-white solid to obtain a white solid; drying the white solid under reduced pressure to constant weight, the pressure of the reduced pressure drying is 40-80 KPa, and the temperature of the reduced pressure drying is 20-60°C to obtain 1-bromo-dibenzofuran.

[0018] Furthermore, the molar ratio of the 2,3-dibromofluorobenzene, phenol, strong base weak acid salt and catalyst A is 1:0.9-1.0:2.0-5.0:0.01-0.1; the molar ratio of the 2,3-dibromofluorobenzene, base, initiator and catalyst B is 1:1.5-3.0:0.01-0.1:0.01-0.05.

[0019] Furthermore, in step S1 and step S2, the solvent is one or more of N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, toluene, decalin, tetrahydrofuran or 1,4-dioxane.

[0020] The present invention has the following beneficial effects: The present invention provides a novel synthesis method of 1-bromodibenzofuran. 2,3-dibromofluorobenzene and phenol are used as raw materials, and ether substances are synthesized by Williamson reaction. The obtained ether substances are subjected to extraction, suction filtration and rotary evaporation processes to obtain intermediate 1. Intermediate 1 and related auxiliary agents are subjected to ring-closing reaction to obtain a reaction liquid; the reaction liquid is subjected to extraction, suction filtration and reduced pressure drying processes to prepare the target molecule 1-bromodibenzofuran. The raw materials used in the synthesis of 1-bromodibenzofuran by the present invention are green, non-toxic, low-priced and easy to obtain, and can effectively reduce production costs. In addition, the reaction process of synthesizing 1-bromodibenzofuran uses fewer types of reagents, a short synthesis route, and a simple post-treatment process, and the target product 1-bromodibenzofuran finally obtained has high purity and high yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 This is the hydrogen nuclear magnetic resonance spectrum of 1-bromo-dibenzofuran prepared in Example 1. DETAILED DESCRIPTION

[0023] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] Example 1 This embodiment provides an efficient and environmentally friendly synthesis process of 1-bromo-dibenzofuran, comprising the following steps: S1. Add 2.54g (10mmol) of 2,3-dibromofluorobenzene and 0.94g (10mmol) of phenol to a 250mL single-mouth glass reaction bottle, and then add 35mL of dimethyl sulfoxide and stir until completely dissolved. Then weigh 3.538g (20mmol) of sodium phosphate and 0.95g (0.5mmol) of cuprous iodide and add them to the above glass reaction bottle. The single-mouth glass reaction bottle was replaced with nitrogen three times to place the single-mouth glass reaction bottle in an inert gas environment. Then the single-mouth glass reaction bottle was transferred to a constant temperature heating box, first heated to 90°C, stirred at 100r / min for 1h, and then the constant temperature heating box was heated to 120°C and heated for 6h. The reaction was completed to obtain a reaction solution.

[0025] Post-treatment: The reaction solution was cooled to room temperature, and then extracted with dichloromethane and water to obtain an organic phase; the organic phase was dried by adding anhydrous sodium sulfate, and then filtered to collect the filtrate. The filtrate was evaporated under reduced pressure to remove dichloromethane to obtain intermediate 1.

[0026] S2. Add all the intermediate 1 mentioned above into a glass reaction bottle, add 40 ml of decahydronaphthalene, and then add 4 ml of 0.257 g / mL sodium ethoxide aqueous solution (the mass of sodium ethoxide is 1.028 g, and the molar number is 15 mmol) at 0.5 mL / min. After the addition is completed, replace nitrogen three times in the three-mouth glass reaction bottle, and then add 0.052 g (0.53 mmol) of nickel acetate, and mix and stir at 200 r / min for 5 min; then add 0.1 g (1 mmol) of trimethylacetic acid to the glass reaction bottle, and then heat the glass reaction bottle to 100°C for reaction for 2 h. The reaction is completed to obtain a reaction solution.

[0027] Post-treatment: The reaction solution was poured into ice water while hot, stirred for 10 minutes, and then allowed to stand, and then filtered to obtain an upper off-white solid; the obtained off-white solid was added to 100 mL of petroleum ether and water (V petroleum ether / V water = 4:1), heated to 60°C, then cooled to room temperature, and filtered to obtain a white solid. The white solid was placed in a vacuum drying oven and dried to constant weight. The vacuum drying pressure was 90Kpa and the vacuum drying temperature was 40°C to obtain 1.74 g of white needle-shaped solid 1-bromo-dibenzofuran; the purity of 1-bromo-dibenzofuran was 99.9%, and the yield was 69.8%.

[0028] Example 2 This embodiment provides an efficient and environmentally friendly synthesis process of 1-bromo-dibenzofuran, comprising the following steps: S1. Add 5.08g (20mmol) of 2,3-dibromofluorobenzene and 1.88g (20mmol) of phenol to a 250mL single-mouth glass reaction bottle, and then add 60mL of N,N-dimethylformamide and stir until completely dissolved. Then weigh 6.91g (50mmol) of potassium carbonate and 0.95g (0.5mmol) of cuprous iodide and add them to the above glass reaction bottle. The single-mouth glass reaction bottle was replaced with nitrogen three times to place the single-mouth glass reaction bottle in an inert gas environment. Then transfer the single-mouth glass reaction bottle to a constant temperature heating box, first heat it to 90°C, stir it at 100r / min for 1h, then heat the constant temperature heating box to 120°C and heat it for 6h, the reaction is completed, and a reaction solution is obtained.

[0029] Post-treatment: The reaction solution was cooled to room temperature, and then extracted with dichloromethane and water to obtain an organic phase; the organic phase was dried by adding anhydrous sodium sulfate, and then filtered to collect the filtrate. The filtrate was evaporated under reduced pressure to remove dichloromethane to obtain intermediate 1.

[0030] S2. Add all the intermediate 1 mentioned above into a glass reaction bottle, add 60 ml of decahydronaphthalene, and then add 2.4 ml of 0.4 g / mL lithium hydroxide aqueous solution (the mass of lithium hydroxide is 0.96 g, and the molar number is 40 mmol) at 0.4 mL / min. After the addition is completed, replace nitrogen three times in the three-mouth glass reaction bottle, and then add 0.176 g (1 mmol) of nickel acetate, and mix and stir at 250 r / min for 5 min; then add 0.2 g (2 mmol) of trimethylacetic acid to the glass reaction bottle, and then heat the glass reaction bottle to 100°C for reaction for 2 h. The reaction is completed to obtain a reaction solution.

[0031] Post-treatment: The reaction solution was poured into ice water while hot, stirred for 10 min, and then allowed to stand, and then filtered to obtain a gray solid on the upper layer; the obtained gray solid was added to 100 mL of petroleum ether and water (V 石油醚 / V 水 =4:1), heated to 60°C, then cooled to room temperature, filtered, and a white solid was obtained. The white solid was placed in a vacuum drying oven and dried to constant weight. The vacuum drying pressure was 90Kpa and the vacuum drying temperature was 40°C to obtain 3.01 g of white solid 1-bromo-dibenzofuran; the purity of 1-bromo-dibenzofuran was 98.9%, and the yield was 61%.

[0032] Example 3 This embodiment provides an efficient and environmentally friendly synthesis process of 1-bromo-dibenzofuran, comprising the following steps: S1. Add 5.08g (20mmol) of 2,3-dibromofluorobenzene and 1.88g (20mmol) of phenol to a 250mL single-mouth glass reaction bottle, and then add 60mL of N,N-dimethylformamide and stir until completely dissolved. Then weigh 6.91g (50mmol) of potassium carbonate and 0.76g (0.6mmol) of ferrous chloride and add them to the above glass reaction bottle. The single-mouth glass reaction bottle is replaced with nitrogen three times to place the single-mouth glass reaction bottle in an inert gas environment. Then transfer the single-mouth glass reaction bottle to a constant temperature heating box, first heat it to 90°C, stir it at 100r / min for 1h, then heat the constant temperature heating box to 120°C and heat it for 6h, the reaction is completed, and a reaction solution is obtained.

[0033] Post-treatment: The reaction solution was cooled to room temperature, and then extracted with dichloromethane and water to obtain an organic phase; the organic phase was dried by adding anhydrous sodium sulfate, and then filtered to collect the filtrate. The filtrate was evaporated under reduced pressure to remove dichloromethane to obtain intermediate 1.

[0034] S2. Add all the intermediate 1 mentioned above into a glass reaction bottle, add 60 ml of toluene, and then add 9.5 ml of 0.4 g / mL lithium hydroxide aqueous solution (the mass of lithium hydroxide is 3.8 g, and the molar number is 34 mmol) at 0.5 mL / min. After the addition is completed, replace nitrogen three times in the three-mouth glass reaction bottle, and then add 0.179 g (0.8 mmol) of palladium acetate, and mix and stir at 300 r / min for 5 min; then add 0.34 g (1.6 mmol) of sodium periodate to the glass reaction bottle, and then heat the glass reaction bottle to 100°C for reaction for 2 h. The reaction is completed to obtain a reaction solution.

[0035] Post-treatment: The reaction solution was poured into ice water while hot, stirred for 10 min, and then allowed to stand, and then filtered to obtain a gray solid on the upper layer; the obtained gray solid was added to 100 mL of petroleum ether and water (V 石油醚 / V 水 =4:1), heated to 60°C, then cooled to room temperature, filtered, and a white solid was obtained. The white solid was placed in a vacuum drying oven and dried to constant weight. The vacuum drying pressure was 90Kpa and the vacuum drying temperature was 40°C to obtain 3.26g of white solid 1-bromo-dibenzofuran; the purity of 1-bromo-dibenzofuran was 98.1%, and the yield was 66%.

[0036] Example 4 This embodiment provides an efficient and environmentally friendly synthesis process of 1-bromo-dibenzofuran, comprising the following steps: S1. Add 5.08g (20mmol) of 2,3-dibromofluorobenzene and 1.692g (18mmol) of phenol to a 250mL single-mouth glass reaction bottle, and then add 60mL of N,N-dimethylformamide and stir until completely dissolved. Then weigh 5.53g (40mmol) of potassium carbonate and 1.14g (0.6mmol) of cuprous iodide and add them to the above glass reaction bottle. The single-mouth glass reaction bottle was replaced with nitrogen three times to place the single-mouth glass reaction bottle in an inert gas environment. Then transfer the single-mouth glass reaction bottle to a constant temperature heating box, first heat it to 80°C, stir it at 200r / min for 04min, then heat the constant temperature heating pot to 110°C and heat it to 5h, the reaction is completed, and the reaction solution is obtained.

[0037] Post-treatment: The reaction solution was cooled to room temperature, and then extracted with dichloromethane and water to obtain an organic phase; the organic phase was dried by adding anhydrous sodium sulfate, and then filtered to collect the filtrate. The filtrate was evaporated under reduced pressure to remove dichloromethane to obtain intermediate 1.

[0038] S2. Add all the intermediate 1 mentioned above into a glass reaction bottle, add 60 ml of toluene, and then add 2.4 ml of 0.3 g / mL lithium hydroxide aqueous solution (the mass of lithium hydroxide is 0.96 g, and the molar number is 40 mmol) dropwise at 0.4 mL / min. After the addition is completed, replace nitrogen three times in the three-mouth glass reaction bottle, and then add 0.176 g (1 mmol) of nickel acetate, and mix and stir at 300 r / min for 5 min; then add 0.2 g (2 mmol) of trimethylacetic acid to the glass reaction bottle, and then heat the glass reaction bottle to 110°C for reaction for 2 h. The reaction is completed to obtain a reaction solution.

[0039] Post-treatment: The reaction solution was poured into ice water while hot, stirred for 10 minutes, and then allowed to stand, and then filtered to obtain a gray solid on the upper layer; the obtained gray solid was added to 100 mL of petroleum ether and water (V petroleum ether / V water = 4:1), heated to 60°C, then cooled to room temperature, and filtered to obtain a white solid. The white solid was placed in a vacuum drying oven and dried to constant weight. The vacuum drying pressure was 90Kpa and the vacuum drying temperature was 40°C to obtain 3.01 g of white solid 1-bromo-dibenzofuran; the purity of 1-bromo-dibenzofuran was 99.7%, and the yield was 64%.

[0040] Example 5 Compared with Example 1, in step S1, the strong base weak acid salt is changed from "sodium phosphate" to "potassium acetate", and the amounts of other substances and steps remain unchanged to synthesize 1-bromo-dibenzofuran, and the purity of 1-bromo-dibenzofuran is 97.7%, and the yield is 64.8%.

[0041] Example 6 Compared with Example 1, in step S1, catalyst A is changed from "cuprous iodide" to "copper", and the amounts of other substances and steps remain unchanged to synthesize 1-bromo-dibenzofuran. The purity of 1-bromo-dibenzofuran is 97.7%, and the yield is 53%.

[0042] Example 7 Compared with Example 1, in step S2, the base is changed from "sodium ethoxide" to "potassium tert-butoxide", and the amounts of other substances and steps remain unchanged to synthesize 1-bromo-dibenzofuran, and the purity of 1-bromo-dibenzofuran is 98.1%, and the yield is 68%.

[0043] Comparative Example 1 Compared with Example 4, in step S2, "trimethylacetic acid" is not added, and the other steps remain unchanged to prepare 1-bromo-dibenzofuran. The purity of 1-bromo-dibenzofuran is 95%, and the yield is 33%.

[0044] Comparative Example 2 Compared with Example 1, in step S1, each reaction monomer is not pre-heated for activation, and the temperature is directly raised to 120° C. and heated for 6 hours. The remaining steps remain unchanged to prepare 1-bromo-dibenzofuran. The purity of 1-bromo-dibenzofuran is 95%, and the yield is 45%.

[0045] Table 1. Sample performance test data

[0046] Data Analysis: According to the data of Table 1, the purity of 1-bromo-dibenzofuran prepared by Example 1-4 is higher, all reaching more than 98%, and the yield of 1-bromo-dibenzofuran prepared by Example 1-4 is more than 60%. In the ring-closing reaction, initiator is added, the reaction chain can be started, the reaction process is accelerated, so as to promote the reaction to be carried out, and the yield and purity of the product are improved. However, compared to Example 4, in Comparative Example 1, step S2 does not add initiator trimethylacetic acid, and the purity of the product 1-bromo-dibenzofuran prepared by Comparative Example 1 is reduced to 95%, and the yield is significantly reduced, which is only 33%.

[0047] In the Williamson synthesis reaction, heating can accelerate the nucleophilic substitution process and increase the reaction rate; in addition, heating and activating each reaction monomer in advance can improve the selectivity of the reaction and increase the product yield. In Comparative Example 2, compared with Example 1, each reaction monomer in step S1 is not pre-heated and activated, and the temperature is increased to react and prepare intermediate 1, so that the purity and yield of the final product 1-bromo-dibenzofuran are reduced.

[0048] The above contents are merely examples and explanations of the structure of the present invention. The technicians in this technical field may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the structure of the invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

[0049] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0050] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to only specific implementation methods. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. An efficient and environmentally friendly synthesis process of 1-bromo-dibenzofuran, It is characterized in that The following steps are involved: S1, 2,3-dibromofluorobenzene, phenol, a strong base and a weak acid salt, a solvent and a catalyst A are subjected to a Williamson synthesis reaction to obtain a reaction liquid; the reaction liquid is subjected to a post-process treatment to obtain an intermediate 1; S2, intermediate 1, solvent, base, initiator and catalyst B are subjected to a ring-closing reaction to obtain a reaction liquid; the reaction liquid is subjected to a post-process to synthesize 1-bromo-dibenzofuran.

2. A highly efficient and environmentally friendly 1-bromo-dibenzofuran synthesis process according to claim 1, It is characterized in that In step S1, the strong base and weak acid salt is any one of sodium carbonate, sodium acetate, sodium hydrosulfide, sodium phosphate, sodium bicarbonate, potassium acetate, potassium hydrogen phosphate or potassium carbonate; and the catalyst A is any one of copper, iodine, cuprous iodide or ferrous chloride.

3. A highly efficient and environmentally friendly 1-bromo-dibenzofuran synthesis process according to claim 1, It is characterized in that In step S1, the Williamson synthesis reaction is carried out under an inert gas atmosphere, and each reaction monomer needs to be heated first, and then the temperature is increased to react; wherein the heating temperature is 50-90°C, and the temperature of the temperature reaction is 90-150°C.

4. A highly efficient and environmentally friendly 1-bromo-dibenzofuran synthesis process according to claim 1, It is characterized in that In step S1, the post-processing steps are: extracting the reaction solution with dichloromethane and water, collecting the organic phase; drying and filtering the organic phase to obtain a filtrate; and removing dichloromethane from the filtrate under reduced pressure to obtain an intermediate 1.

5. A highly efficient and environmentally friendly 1-bromo-dibenzofuran synthesis process according to claim 1, It is characterized in that In step S2, the base includes at least one of sodium tert-butoxide, potassium tert-butoxide, sodium acetate, potassium acetate, sodium ethoxide, lithium hydroxide or potassium hydroxide; before adding the base, it needs to be configured as an aqueous solution of the base, and the concentration of the aqueous solution is 0.1g / mL-0.5g / mL.

6. A highly efficient and environmentally friendly 1-bromo-dibenzofuran synthesis process according to claim 1, It is characterized in that In step S2, the catalyst B is any one of palladium acetate, triphenylphosphine palladium or nickel acetate; the initiator is any one of trimethylacetic acid, benzoyl peroxide, ethyl peroxide, sodium periodate or azobisisobutyronitrile.

7. A highly efficient and environmentally friendly 1-bromo-dibenzofuran synthesis process according to claim 1, It is characterized in that In step S2, the ring-closure reaction is carried out under an inert gas atmosphere, and the reaction temperature of the ring-closure reaction is 60-130°C.

8. A highly efficient and environmentally friendly 1-bromo-dibenzofuran synthesis process according to claim 1, It is characterized in that In step S2, the post-processing is as follows: the reaction solution is poured into ice water while hot, allowed to stand, and filtered to obtain an upper gray-white solid; the gray-white solid is extracted and filtered to obtain a white solid; the white solid is dried under reduced pressure to constant weight, the pressure of the reduced pressure drying is 40-80 KPa, and the temperature of the reduced pressure drying is 20-60° C., to obtain 1-bromo-dibenzofuran.

9. A highly efficient and environmentally friendly 1-bromo-dibenzofuran synthesis process according to claim 1, It is characterized in that The molar ratio of the 2,3-dibromofluorobenzene, phenol, strong base weak acid salt and catalyst A is 1:0.9-1.0:2.0-5.0:0.01-0.1; the molar ratio of the 2,3-dibromofluorobenzene, base, initiator and catalyst B is 1:1.5-3.0:0.01-0.1:0.01-0.

05.

10. The highly efficient and environmentally friendly 1-bromo-dibenzofuran synthesis process according to claim 1, It is characterized in that In step S1 and step S2, the solvent is one or more of N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, toluene, decalin, tetrahydrofuran or 1,4-dioxane.

Images