A preparation method of 9-anthraceneboric acid

Abstract

The present invention relates to a kind of preparation method of 9 anthracene boronic acid, belong to the field of chemical synthesis technology.The preparation method of 9 anthracene boronic acid that the present invention is provided, using refined anthracene, diboric acid as raw material, under the effect of catalyst, ligand and oxidant, by one-step C H boration reaction prepares 9 anthracene boronic acid.In prior art, the preparation of 9 anthracene boronic acid mainly often first uses refined anthracene as raw material to synthesize 9 bromoanthracene (Path B) through bromination reaction, then using 9 bromoanthracene, n-butyllithium and trimethyl borate etc. as raw material, at 78 DEG C, low temperature lithiation boration reaction prepares 9 anthracene boronic acid (Path A), reaction process is complicated, condition is harsh;And the present invention solves the above problem from the root, directly using cheap refined anthracene, diboric acid as raw material, one-step C H boration reaction obtains product 9 anthracene boronic acid, compared with prior art, reactions steps is short, without intermediate product, also saves the steps such as intermediate product purification, purification, more simple and efficient.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical synthesis, and in particular relates to a method for preparing 9-anthraceneboric acid. Background Art

[0002] 9-Anthraceneboronic acid is an important chemical intermediate that can be used to further synthesize organic optoelectronic materials. Organic optoelectronic materials have been widely used in organic / polymer light-emitting diodes (OLED / PLED), photodetectors, organic solar cells (OSC), nonlinear optical devices, organic field-effect transistors (OFET), etc. Therefore, studying the synthesis of 9-anthraceneboronic acid is of great significance.

[0003] As shown in the following reaction formula, industrially, 9-anthracene boronic acid is mainly prepared from 9-bromoanthracene, n-butyl lithium, and trimethyl borate via a low-temperature lithiation and boration reaction at -78°C (Path A). The raw material 9-bromoanthracene is synthesized from refined anthracene via a bromination reaction (Path B).

[0004]

[0005] The above reaction steps are cumbersome, time-consuming, and the reaction conditions are harsh. Therefore, it is inevitable to continuously study the synthesis method of 9-anthraceneboronic acid in order to obtain a new route for the synthesis of 9-anthraceneboronic acid that is more economical, green, and efficient.

[0006] The information disclosed in this background technology section is only intended to enhance understanding of the overall background of the invention and should not be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the Invention

[0007] In order to solve the technical problems of complex steps and harsh conditions in the preparation of 9-anthraceneboric acid in the prior art, a method for preparing 9-anthraceneboric acid by a one-step C—H borylation reaction directly using anthracene and diboric acid as raw materials is provided.

[0008] A method for preparing 9-anthracene boronic acid, using refined anthracene and diboric acid as raw materials, to prepare 9-anthracene boronic acid through a one-step C—H borylation reaction, the reaction formula is as follows:

[0009]

[0010] In some embodiments, 9-anthraceneboric acid is prepared by using anthracene and diboric acid as raw materials, adding a solvent, and under the action of a catalyst, a ligand, and an oxidant.

[0011] In some embodiments, the molar ratio of the solvent, diboric acid, catalyst, ligand, oxidant and anthracene is (3-15): (1-3): (0.05-0.1): (0.1-0.2): (1-3): 1.

[0012] In some embodiments, the steps include: under nitrogen protection, mixing a solvent, anthracene, diboric acid, a catalyst, a ligand and an oxidant, heating, stirring and keeping warm for a certain time, and obtaining 9-anthraceneboric acid through post-treatment.

[0013] In some embodiments, the heating temperature is 60° C. to 110° C.; and / or the insulation reaction time is 6 hours to 24 hours. There is no particular requirement for the stirring speed, as long as it can mix the solution evenly. Preferably, the stirring speed is 600 rpm.

[0014] The post-treatment is carried out by extraction. Preferably, after the reaction is completed, the solvent is first recovered, and water and xylene are added for extraction. The organic layer is desolventized and crystallized to obtain 9-anthraceneboric acid.

[0015] In some embodiments, the solvent is selected from one or more of dichloroethane, chloroform, tetrahydrofuran, dioxane, o-dichlorobenzene, and chlorobenzene.

[0016] In some embodiments, the catalyst is a copper salt. Preferably, the copper salt is selected from one or more of cuprous iodide, cuprous chloride, cuprous bromide, cuprous oxide, copper sulfate, cupric chloride, copper acetate, and copper trifluoroacetate.

[0017] In some embodiments, the oxidant is selected from one or more of hydrogen peroxide, di-tert-butyl peroxide, tert-butyl hydroperoxide, potassium persulfate, and oxygen.

[0018] In some embodiments, the ligand is a β-diketimine ligand.

[0019] In some embodiments, the structure of the β-diketimine ligand is as follows:

[0020]

[0021] wherein: R1 is selected from H, R2 is selected from Me (ligand L1) or R1 is selected from Me, R2 is selected from H (ligand L2) or R1 is selected from H, R2 is selected from Cl (ligand L3) or R1 is selected from Cl, R2 is selected from H (ligand L4).

[0022] Compared with the prior art, the present invention achieves the following technical effects:

[0023] (1) In the prior art, the preparation of 9-anthracene boronic acid often involves first using refined anthracene as a raw material to synthesize 9-bromoanthracene (Path B) through a bromination reaction, and then using 9-bromoanthracene, n-butyl lithium and trimethyl borate as raw materials to obtain 9-anthracene boronic acid (Path A) through a low-temperature lithiation and boration reaction at -78°C. The reaction process is complicated and the conditions are harsh. The present invention fundamentally solves the above problems, directly using cheap refined anthracene and diboric acid as raw materials, and obtaining the product 9-anthracene boronic acid (Path C) through a one-step C—H boration reaction. Compared with the prior art, the present invention will greatly reduce the number of synthesis steps, improve atom utilization, reduce production costs, and eliminate the need for intermediate products, thereby eliminating the need for intermediate product purification and purification steps, making it simpler and more efficient. The synthetic route of the prior art and the improved route of the present invention are as follows: Figure 1 shown.

[0024] (2) The present invention has mild conditions and can react at a relatively low temperature (60°C to 110°C). The raw materials are easily available, and the process has the advantages of low production cost and environmental friendliness. The post-processing and purification is simple and the yield is high, with a yield of more than 90%. The product quality is good and the purity is high, reaching more than 99.9%, which is conducive to the implementation of large-scale industrial production.

[0025] (3) The ligand used in the present invention is crucial to the reaction. The ligand used is a specific type of ligand specifically selected for the reaction system. By changing the substituents on the ligand's benzene ring, the ligand's electrical conductivity and steric hindrance are enhanced. When a methyl group is introduced into the ligand's benzene ring, the ligand's strong electrical conductivity and large steric hindrance allow it to coordinate with the copper salt, significantly improving the catalytic effect. Without the addition of a ligand or with the addition of a conventional ligand (such as 1,10-phenanthroline), the reaction essentially fails to proceed. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is the synthetic route of 9-anthraceneboronic acid in the prior art and the improved route of the present invention. DETAILED DESCRIPTION

[0027] The technical solutions of the present invention are described below by means of specific embodiments in conjunction with the accompanying drawings. It should be understood that the one or more steps mentioned in the present invention do not exclude the presence of other methods and steps before and after the combined steps, or other methods and steps may be inserted between these explicitly mentioned steps. It should also be understood that these examples are only used to illustrate the present invention and are not used to limit the scope of the present invention. Unless otherwise specified, the numbering of each method step is only for the purpose of identifying each method step, and does not limit the order of arrangement of each method or limit the scope of implementation of the present invention. Changes or adjustments in their relative relationships can also be regarded as the scope of implementation of the present invention without substantial changes in the technical content.

[0028] The sources of the raw materials and instruments used in the examples are not particularly limited and can be purchased from the market or prepared according to conventional methods known to those skilled in the art.

[0029] Example 1: A method for preparing 9-anthraceneboronic acid

[0030] Under nitrogen protection, 269.5g of dichloroethane (99%), 53.9g of anthracene (99%, 0.3mol), 54.3g of diboric acid (99%, 0.6mol), 2.9g of cuprous iodide (99%, 0.015mol), 9.3g of ligand L1 (99%, 0.03mol), and 90.3g of di-tert-butyl peroxide (97%, 0.6mol) were added to a 1000mL reaction bottle. After the addition, the temperature was raised to 80°C, the stirring speed was 600rpm, and the reaction was kept warm for 12h. After the reaction was completed, the solvent was recovered, water and xylene were added to the residue for extraction, and the organic layer was desolvated to obtain a crude product, which was crystallized with toluene to obtain 59.3g of 9-anthraceneboric acid with a content of 99.9% and a yield of 88.9%.

[0031] The reaction mechanism of the above reaction is as follows:

[0032] During the reaction, the copper salt of the catalyst coordinates with the ligand to form cuprous β-diketoimine, which reacts with the oxidant di-tert-butyl peroxide to produce a tert-butoxy β-diketoimine copper intermediate, which then reacts with diboric acid to produce a boronic acid β-diketoimine copper intermediate. In the presence of the oxidant, anthracene generates a 9-anthracene free radical, which undergoes addition and reductive elimination reactions with the boronic acid β-diketoimine copper intermediate to produce 9-anthraceneboric acid and cuprous β-diketoimine.

[0033] Example 2: A method for preparing 9-anthraceneboronic acid

[0034] Under nitrogen protection, 539g o-dichlorobenzene (99%), 53.9g anthracene (99%, 0.3mol), 81.5g diboric acid (99%, 0.9mol), 5.8g cuprous iodide (99%, 0.03mol), 17.5g ligand L4 (99%, 0.045mol), 135.5g di-tert-butyl peroxide (97%, 0.9mol) were added to a 1000mL reaction flask. After the addition, the temperature was raised to 110°C, the stirring speed was 600rpm, and the reaction was kept warm for 24h. After the reaction was completed, the solvent was recovered, water and xylene were added to the residue for extraction, and the organic layer was desolvated to obtain a crude product, which was crystallized with toluene to obtain 61.1g 9-anthraceneboric acid with a content of 99.9% and a yield of 91.6%.

[0035] Example 3: A method for preparing 9-anthraceneboronic acid

[0036] Under nitrogen protection, 269.5 g of dioxane (99%), 53.9 g of anthracene (99%, 0.3 mol), 27.2 g of diboric acid (99%, 0.3 mol), 3.0 g of cuprous chloride (99%, 0.03 mol), 16.9 g of ligand L2 (99%, 0.06 mol), and 83.6 g of potassium persulfate (99%, 0.3 mol) were added to a 1000 mL reaction bottle. After the addition, the temperature was raised to 90 ° C., the stirring speed was 600 rpm, and the reaction was kept warm for 24 h. After the reaction was completed, the solvent was recovered, water and xylene were added to the residue for extraction, and the organic layer was desolvated to obtain a crude product, which was crystallized with toluene to obtain 10.3 g of 9-bromoanthracene with a content of 98.2% and a yield of 15.2%.

[0037] By comparing Example 3 with Example 1, it was found that the yield of 9-bromoanthracene obtained in Example 3 was much lower than that in Example 1. This is because the oxidizing property of di-tert-butyl peroxide is significantly stronger than that of potassium persulfate, and the steric hindrance is relatively large, which is conducive to promoting the occurrence of the reaction.

[0038] Comparative Example 1: No ligand added

[0039] This comparative example differs from Example 1 in that no ligand is added.

[0040] Under nitrogen protection, 269.5 g of dichloroethane (99%), 53.9 g of anthracene (99%, 0.3 mol), 54.3 g of diboric acid (99%, 0.6 mol), 2.9 g of cuprous iodide (99%, 0.015 mol), and 90.3 g of di-tert-butyl peroxide (97%, 0.6 mol) were added to a 1000 mL reaction bottle. After the addition, the temperature was raised to 80 ° C., the stirring speed was 600 rpm, and the reaction was kept warm for 12 h. After the reaction was completed, the solvent was recovered, water and xylene were added to the residue for extraction, and the organic layer was sampled for GC-MS analysis. No product 9-bromoanthracene was detected.

[0041] Comparative Example 2: Using conventional type ligands

[0042] This comparative example is different from Example 1 in that the ligand is replaced with a conventional ligand: 1,10-phenanthroline.

[0043] Under nitrogen protection, 269.5 g of dichloroethane (99%), 53.9 g of anthracene (99%, 0.3 mol), 54.3 g of diboric acid (99%, 0.6 mol), 2.9 g of cuprous iodide (99%, 0.015 mol), 6.0 g of 1,10-phenanthroline (99%, 0.03 mol), and 90.3 g of di-tert-butyl peroxide (97%, 0.6 mol) were added to a 1000 mL reaction bottle. After the addition, the temperature was raised to 80 ° C., the stirring speed was 600 rpm, and the reaction was kept warm for 12 h. After the reaction was completed, the solvent was recovered, water and xylene were added to the residue for extraction, and the organic layer was sampled for GC-MS analysis. The quantitative yield of 9-bromoanthracene was less than 1%.

[0044] Comparative Example 3: No catalyst added

[0045] This comparative example differs from Example 1 in that no catalyst is added.

[0046] Under nitrogen protection, 269.5 g of dichloroethane (99%), 53.9 g of anthracene (99%, 0.3 mol), 54.3 g of diboric acid (99%, 0.6 mol), 9.3 g of ligand L1 (99%, 0.03 mol), and 90.3 g of di-tert-butyl peroxide (97%, 0.6 mol) were added to a 1000 mL reaction bottle. After the addition was completed, the temperature was raised to 80°C, the stirring speed was 600 rpm, and the reaction was kept warm for 12 hours. After the reaction was completed, the solvent was recovered, water and xylene were added to the residue for extraction, and the organic layer was sampled for GC-MS analysis. The quantitative yield of 9-bromoanthracene was less than 1%.

[0047] Comparative Example 4: No oxidant added

[0048] This comparative example differs from Example 1 in that no oxidant is added.

[0049] Under nitrogen protection, 269.5 g of dichloroethane (99%), 53.9 g of anthracene (99%, 0.3 mol), 54.3 g of diboric acid (99%, 0.6 mol), 2.9 g of cuprous iodide (99%, 0.015 mol), and 9.3 g of ligand L1 (99%, 0.03 mol) were added to a 1000 mL reaction bottle. After the addition, the temperature was raised to 80 ° C, the stirring speed was 600 rpm, and the reaction was kept warm for 12 h. After the reaction was completed, the solvent was recovered, water and xylene were added to the residue for extraction, and the organic layer was sampled for GC-MS analysis. The quantitative yield of 9-bromoanthracene was less than 1%.

[0050] The foregoing descriptions of specific exemplary embodiments of the present invention are for purposes of illustration and description. These descriptions are not intended to limit the invention to the precise forms disclosed, and it is apparent that many variations and modifications are possible in light of the foregoing teachings. The exemplary embodiments have been selected and described for the purpose of explaining the specific principles of the invention and their practical application, thereby enabling those skilled in the art to realize and utilize a variety of exemplary embodiments of the invention and various options and modifications. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A method for preparing 9-anthraceneboronic acid, characterized in that: 9-Anthraceneboric acid is prepared by a one-step C—H borylation reaction using anthracene and diboric acid as raw materials, adding a solvent, and under the action of a catalyst, a ligand, and an oxidant. The reaction formula is as follows: The catalyst is selected from one or more of cuprous iodide, cuprous chloride, cuprous bromide, cuprous oxide, copper sulfate, cupric chloride, copper acetate, and copper trifluoroacetate; The oxidant is selected from one or more of hydrogen peroxide, di-tert-butyl peroxide, tert-butyl hydroperoxide, and potassium persulfate; The ligand is a β-diketimine ligand with the following structure: wherein: R1 is selected from H, R2 is selected from Me (ligand L1) or R1 is selected from Me, R2 is selected from H (ligand L2) or R1 is selected from H, R2 is selected from Cl (ligand L3) or R1 is selected from Cl, R2 is selected from H (ligand L4).

2. The method for preparing 9-anthraceneboronic acid according to claim 1, wherein The molar ratio of the solvent, diboric acid, catalyst, ligand, oxidant and anthracene is (3-15):(1-3):(0.05-0.1):(0.1-0.2):(1-3):

1.

3. The method for preparing 9-anthraceneboric acid according to claim 1 or 2, characterized in that the steps include: Under nitrogen protection, a solvent, refined anthracene, diboric acid, a catalyst, a ligand and an oxidant are mixed, heated, stirred and kept warm for a certain time, and then post-treated to obtain 9-anthraceneboric acid.

4. The method for preparing 9-anthraceneboric acid according to claim 3, wherein The heating temperature is 60° C. to 110° C.; and / or the insulation reaction time is 6 h to 24 h.

5. The method for preparing 9-anthraceneboric acid according to claim 2, wherein The solvent is selected from one or more of dichloroethane, chloroform, tetrahydrofuran, dioxane, o-dichlorobenzene, and chlorobenzene.

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