A method for synthesizing dibenzothiophene

Abstract

This invention belongs to the field of compound synthesis technology, specifically disclosing a method for synthesizing dibenzothiophene. The method uses 2-mercaptobiphenyl as a raw material, employs Ni(COD)2 as a catalyst, adds Xantphos ligand, and reacts with cesium carbonate and ferrous chloride in an organic solvent to prepare dibenzothiophene. The method for synthesizing dibenzothiophene provided by this invention uses inexpensive raw materials, is simple to operate, has convenient post-processing, and is easy to industrialize.

Description

Technical Field

[0001] This invention relates to the field of compound synthesis technology, and specifically to a method for synthesizing dibenzothiophene. Background Technology

[0002] Dibenzothiophene and its derivatives are an important class of organic compounds with very broad application prospects. For example, they can be used to synthesize new materials such as liquid crystal polymers and superconductors, and are a new type of organic optoelectronic material. In addition, they also have extremely high application value in the synthesis of pesticides, medicines, biological products and sulfur-indigo dyes.

[0003] There are many reports on the synthesis methods of dibenzothiophene, but in order to improve its applicability and make it easier to industrialize, people have been looking for more efficient and convenient synthesis methods.

[0004] The present invention aims to provide a novel method for synthesizing dibenzothiophene. Summary of the Invention

[0005] The main technical problem solved by this invention is to provide a method for synthesizing dibenzothiophene, which has the advantages of cheap raw materials, simple operation, and easy industrial production.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0007] A method for synthesizing dibenzothiophene, wherein the method uses 2-mercaptobiphenyl as a raw material, employs Ni(COD)2 as a catalyst, adds Xantphos ligand, and reacts with cesium carbonate and ferrous chloride in an organic solvent to prepare dibenzothiophene.

[0008] In one embodiment of the present invention, the reaction is carried out under an inert gas protection, for example, under a nitrogen protection.

[0009] In one embodiment of the present invention, the organic solvent is toluene, preferably anhydrous toluene.

[0010] In one embodiment of the present invention, the reaction temperature is 100℃~120℃, preferably 105℃~112℃.

[0011] In one embodiment of the present invention, the reaction time is 5 to 15 hours, preferably 6 to 12 hours.

[0012] In one embodiment of the present invention, the amount of catalyst Ni(COD)2 is 15% to 25% of the molar amount of 2-mercaptobiphenyl.

[0013] In one embodiment of the present invention, the amount of the Xantphos ligand is 35% to 40% of the molar number of the 2-mercaptobiphenyl.

[0014] In one embodiment of the present invention, the amount of cesium carbonate used is 1.5 to 2.5 times the molar number of 2-mercaptobiphenyl.

[0015] In one embodiment of the present invention, the amount of ferrous chloride used is 1.5 to 2.5 times the molar number of 2-mercaptobiphenyl.

[0016] Preferably, the amount of catalyst Ni(COD)2 is 20% of the molar amount of 2-mercaptobiphenyl; and / or, the amount of Xantphos ligand is 40% of the molar amount of 2-mercaptobiphenyl; and / or, the amount of cesium carbonate is twice the molar amount of 2-mercaptobiphenyl; and / or, the amount of ferrous chloride is twice the molar amount of 2-mercaptobiphenyl.

[0017] As one embodiment of the present invention, the method further includes a post-reaction treatment, the post-reaction treatment step comprising:

[0018] Cool the reaction solution to 20℃~30℃, then filter and collect the filtrate;

[0019] The solvent was removed from the filtrate by evaporation, and then recrystallized with an ethanol-water mixture to obtain the dibenzothiophene product.

[0020] In one embodiment of the present invention, the ethanol and water mixture is mixed in a volume ratio of (1-3):(1-3), preferably in a volume ratio of (2-3):1, and more preferably in a volume ratio of 2:1.

[0021] The method for synthesizing dibenzothiophene provided by this invention uses inexpensive raw materials, is simple to operate, has convenient post-processing, and is easy to industrialize; moreover, the target compound obtained has high purity. Attached Figure Description

[0022] Figure 1 This is the 1H NMR spectrum of the dibenzothiophene product obtained in Example 1 of this invention. Detailed Implementation

[0023] The technical solution of the present invention will be described in detail below through embodiments.

[0024] Unless otherwise specified, all raw materials used in the following examples were obtained through purchase.

[0025] Example 1

[0026] This embodiment provides a method for synthesizing dibenzothiophene, and the reaction formula for the synthesis method is as follows:

[0027]

[0028] The reaction steps are as follows:

[0029] 2-Mercaptobiphenyl (18.6 g, 0.1 mol), Ni(COD)₂ (5.5 g, 0.02 mol), and Xantphos ligand (23.1 g, 0.04 mol) were added to 700 mL of anhydrous toluene. Under nitrogen protection, cesium carbonate (65.2 g, 0.2 mol) and ferrous chloride (25.3 g, 0.2 mol) were then added. After the addition was complete, the reaction system was slowly heated to reflux (approximately 110 °C) and refluxed for 10 hours. The reaction was confirmed to be complete by TLC.

[0030] The reaction solution was then cooled to room temperature (approximately 25°C), filtered, and the filtrate was collected and evaporated to dryness to remove the solvent. 200 ml of ethanol / water (2:1; V / V) was added to the evaporated product, and recrystallization was performed to obtain the target product, dibenzothiophene, in a total quantity of 16.8 g, with a yield of 91% and a purity of 98%. The 1H NMR spectrum of the target compound is shown below. Figure 1 As shown.

[0031] Example 2

[0032] This embodiment provides a method for synthesizing dibenzothiophene. The reaction formula for the synthesis method is the same as that in Example 1, and the reaction steps are as follows:

[0033] 2-Mercaptobiphenyl (186 g, 1 mol), Ni(COD)₂ (55 g, 0.2 mol), and Xantphos ligand (231 g, 0.4 mol) were added to 4 L of anhydrous toluene. Under nitrogen protection, cesium carbonate (652 g, 2 mol) and ferrous chloride (253 g, 2 mol) were then added. After the addition was complete, the reaction system was slowly heated to reflux (approximately 110 °C) and refluxed for 12 hours. The reaction was confirmed to be complete by TLC.

[0034] The reaction solution was then cooled to room temperature (approximately 25°C), filtered, and the filtrate was collected and evaporated to dryness to remove the solvent. 1.5 L of ethanol / water (2:1; V / V) was added to the evaporated product, and recrystallization was performed to obtain the target product, dibenzothiophene, in a total quantity of 163 g, with a yield of 89% and a purity of 97%.

[0035] Example 3

[0036] This embodiment provides a method for synthesizing dibenzothiophene. The reaction formula for the synthesis method is the same as that in Example 1, and the reaction steps are as follows:

[0037] 2-Mercaptobiphenyl (18.6 g, 0.1 mol), Ni(COD)₂ (4.1 g, 0.015 mol), and Xantphos ligand (20.3 g, 0.035 mol) were added to 700 mL of anhydrous toluene. Under nitrogen protection, cesium carbonate (65.2 g, 0.2 mol) and ferrous chloride (25.3 g, 0.2 mol) were then added. After the addition was complete, the reaction system was slowly heated to reflux (approximately 110 °C) and refluxed for 10 hours. The reaction was confirmed to be complete by TLC.

[0038] The reaction solution was then cooled to room temperature (approximately 25°C), filtered, and the filtrate was collected and evaporated to dryness to remove the solvent. 200 ml of ethanol / water (2:1; V / V) was added to the evaporated product, and recrystallization was performed to obtain the target product, dibenzothiophene, in a total quantity of 15.3 g, with a yield of 83% and a purity of 96%.

[0039] Example 4

[0040] This embodiment provides a method for synthesizing dibenzothiophene. The reaction formula for the synthesis method is the same as that in Example 1, and the reaction steps are as follows:

[0041] 2-Mercaptobiphenyl (18.6 g, 0.1 mol), Ni(COD)₂ (5.5 g, 0.02 mol), and Xantphos ligand (23.1 g, 0.04 mol) were added to 700 mL of anhydrous toluene. Under nitrogen protection, cesium carbonate (48.8 g, 0.15 mol) and ferrous chloride (19.0 g, 0.15 mol) were then added. After the addition was complete, the reaction system was slowly heated to reflux (approximately 110 °C) and refluxed for 10 hours. The reaction was confirmed to be complete by TLC.

[0042] The reaction solution was then cooled to room temperature (approximately 25°C), filtered, and the filtrate was collected and evaporated to dryness to remove the solvent. 200 ml of ethanol / water (2:1; V / V) was added to the evaporated product, and recrystallization was performed to obtain the target product, dibenzothiophene, in a total quantity of 14.9 g, with a yield of 81% and a purity of 97%.

[0043] Example 5

[0044] This embodiment provides a method for synthesizing dibenzothiophene. The reaction formula for the synthesis method is the same as that in Example 1, and the reaction steps are as follows:

[0045] 2-Mercaptobiphenyl (18.6 g, 0.1 mol), Ni(COD)₂ (5.5 g, 0.02 mol), and Xantphos ligand (23.1 g, 0.04 mol) were added to 900 mL of anhydrous toluene. Under nitrogen protection, cesium carbonate (81.5 g, 0.25 mol) and ferrous chloride (31.7 g, 0.25 mol) were then added. After the addition was complete, the reaction system was slowly heated to reflux (approximately 110 °C) and refluxed for 10 hours. The reaction was confirmed to be complete by TLC.

[0046] The reaction solution was then cooled to room temperature (approximately 25°C), filtered, and the filtrate was collected and evaporated to dryness to remove the solvent. 200 ml of ethanol / water (2:1; V / V) was added to the evaporated product, and recrystallization was performed to obtain the target product, dibenzothiophene, in a total quantity of 15.6 g, with a yield of 85% and a purity of 97%.

[0047] Example 6

[0048] This embodiment provides a method for synthesizing dibenzothiophene, which differs from Example 1 only in the recrystallization solvent used in the post-processing. The specific post-processing method is as follows:

[0049] After the reaction was complete, the reaction solution was cooled to room temperature (approximately 25°C), filtered, and the filtrate was collected and evaporated to dryness to remove the solvent. 200 ml of ethanol / water (3:1; V / V) was added to the evaporated product, and recrystallization was performed to obtain the target product, dibenzothiophene, in a total quantity of 15.9 g, with a yield of 86% and a purity of 97%.

[0050] Example 7

[0051] This embodiment provides a method for synthesizing dibenzothiophene, which differs from Example 1 only in the recrystallization solvent used in the post-processing. The specific post-processing method is as follows:

[0052] After the reaction was complete, the reaction solution was cooled to room temperature (approximately 25°C), filtered, and the filtrate was collected and evaporated to dryness to remove the solvent. 200 ml of ethanol / water (1:1; V / V) was added to the evaporated product, and recrystallization was performed to obtain the target product, dibenzothiophene, in a total quantity of 15.7 g, with a yield of 85% and a purity of 95%.

[0053] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent transformations made based on the content of the present invention specification, or direct or indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A method of synthesis of dibenzothiophene, characterized by, The method uses 2-mercaptobiphenyl as a raw material, employs Ni(COD)2 as a catalyst, adds Xantphos ligand, and reacts with cesium carbonate and ferrous chloride in an organic solvent to prepare dibenzothiophene.

2. The method of synthesis of claim 1, wherein, The reaction is carried out under the protection of an inert gas.

3. The method of synthesis according to claim 1 or 2, wherein, The organic solvent is toluene.

4. The method of synthesis of claim 3, wherein, The reaction temperature is 100℃~120℃.

5. The method of synthesis of claim 4, wherein, The reaction time is 5 to 15 hours.

6. The method of synthesis of claim 1, wherein, The amount of catalyst Ni(COD)2 is 15% to 25% of the molar amount of 2-mercaptobiphenyl; and / or, the amount of Xantphos ligand is 35% to 40% of the molar amount of 2-mercaptobiphenyl.

7. The method of synthesis of claim 6, wherein, The amount of cesium carbonate used is 1.5 to 2.5 times the molar amount of 2-mercaptobiphenyl; and / or, the amount of ferrous chloride used is 1.5 to 2.5 times the molar amount of 2-mercaptobiphenyl.

8. The method of synthesis of claim 7, wherein, The amount of catalyst Ni(COD)2 is 20% of the molar amount of 2-mercaptobiphenyl; the amount of Xantphos ligand is 40% of the molar amount of 2-mercaptobiphenyl; the amount of cesium carbonate is twice the molar amount of 2-mercaptobiphenyl; and the amount of ferrous chloride is twice the molar amount of 2-mercaptobiphenyl.

9. The method of synthesis of claim 8, wherein, The method further includes a post-reaction treatment, the post-reaction treatment step comprising: Cool the reaction solution to 20℃~30℃, then filter and collect the filtrate; The solvent was removed from the filtrate by evaporation, and then recrystallized with an ethanol-water mixture to obtain the dibenzothiophene product.

10. The method of synthesis of claim 9, wherein, In the ethanol-water mixture, ethanol and water are mixed in a volume ratio of (1-3):(1-3).