A method for synthesizing carbazole

Abstract

The present invention discloses a method for synthesizing carbazole. Using indole and 1,4-dichlorobutane as raw materials, the final product carbazole is obtained through a one-step reaction. The method of the present invention has the advantages of cheap and easily available raw materials, convenient production and easy purification, and can be developed into an industrial production method.

Description

Technical Field

[0001] The present invention relates to the technical field of organic synthesis, and particularly relates to a method for synthesizing carbazole. Background Art

[0002] Carbazole is a key intermediate often used in drug research and development, chemical engineering, and optoelectronic materials. There are many reported synthesis methods for carbazole at present, but to a certain extent, there are problems such as relatively expensive raw materials, long reaction steps, and complex purification, which cannot meet the needs of industrial production.

[0003] Therefore, developing a new synthesis method for carbazole is of great significance for realizing the industrial production of carbazole. Summary of the Invention

[0004] The technical problem solved by the present invention is to provide a method for synthesizing carbazole, and the method of the present invention has the advantages of cheap and easily available raw materials, convenient production, environmental protection and safety, and easy purification.

[0005] To solve the above technical problem, the present invention adopts the following technical solution: A method for synthesizing carbazole, and the reaction formula of the synthesis method is:

[0006]

[0007] The synthesis method includes the steps: Under an air atmosphere, indole and 1,4-dichlorobutane are heated under reflux in the presence of aluminum trichloride to prepare the final product carbazole.

[0008] As an embodiment of the present invention, the molar equivalent ratio of indole to 1,4-dichlorobutane = 1:(5 - 10).

[0009] As an embodiment of the present invention, the molar equivalent ratio of indole to aluminum trichloride = 1:(2 - 3).

[0010] Preferably, the molar equivalent ratio of indole to 1,4-dichlorobutane = 1:8.

[0011] Preferably, the molar equivalent ratio of indole to aluminum trichloride = 1:3.

[0012] The beneficial effect of the present invention is: The present invention provides a new method for synthesizing carbazole, using cheap and easily available indole and 1,4-dichlorobutane as raw materials, and obtaining the final product carbazole through a one-step reaction. The method of the present invention has the advantages of cheap and easily available raw materials, convenient production, and easy purification, and can be developed into an industrial production method. Detailed Embodiments

[0013] The technical solution of the present invention will be described in detail below through examples.

[0014] Example 1

[0015] This embodiment provides a method for synthesizing carbazole, and the steps are as follows:

[0016] Under an air atmosphere, 11.7 g of indole was added to a freshly dried three-necked flask (cooled to room temperature under a nitrogen atmosphere), and then 101.6 g of 1,4-dichlorobutane and 39.9 g of aluminum trichloride (newly opened) were added respectively. After addition, the mixture was slowly heated to reflux and reacted for 13 hours under reflux. The reaction was monitored by TLC. After the reaction was complete, the reaction solution was cooled to room temperature, filtered by suction, the filter cake was washed with dichloromethane, and then the filtrate was poured into 250 mL of ice water. After liquid separation, the organic phase was washed with saturated sodium carbonate aqueous solution, dried, concentrated by rotary evaporation, and then recrystallized from 10 mL of ethanol to obtain 15 g of carbazole product with a yield of 89.8%. The NMR of carbazole is as follows: 1 H NMR(DMSO-d6):δ11.05(s,1H),8.12(d,2H),7.49-7.28(m,,4H),7.21-7.19(m,2H).

[0017] During the research process, the following experiments were also carried out. The preparation steps refer to Example 1, and different amounts of reagents were selected, as shown in Table 1 below.

[0018] Table 1

[0019]

[0020] The above are only the embodiments of the present invention, and do not limit the patent scope of the present invention. All equivalent transformations made by using the content of the specification of the present invention, directly or indirectly applied in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. A method for synthesizing carbazole, characterized in that, The reaction formula of the synthesis method is as follows: The synthesis method includes the steps of: under an air atmosphere, indole and 1,4-dichlorobutane are heated and refluxed under the action of aluminum trichloride to prepare the final product carbazole; The molar equivalent ratio of indole to 1,4-dichlorobutane = 1:(5 - 10); the molar equivalent ratio of indole to aluminum trichloride = 1:(2 - 3).

2. The synthesis method according to claim 1, characterized in that, The molar equivalent ratio of indole to 1,4-dichlorobutane = 1:

8.

3. The synthesis method according to claim 2, characterized in that, The molar equivalent ratio of indole to aluminum trichloride = 1:3.

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