Method for preparing 2,7-dibromocarbazole

A technology of dibromocarbazole and dibromobiphenyl, which is applied in the field of organic chemical synthesis, can solve the problems of difficult operation, long reaction time, and high synthesis temperature, achieve shortened reaction time, easy operation and control, and increase product yield Effect

Active Publication Date: 2014-03-26
PUYANG HUICHENG ELECTRONICS MATERIAL +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The disadvantages of this reaction are mainly the high synthesis temperature (up to 180°C) and long reaction time, and the synthesis of the intermediate 2-nitro-4,4'-dibromobiphenyl mainly uses acetic acid as solvent and fuming nitric acid as nitrating reagent , the operation is difficult, and there is environmental pollution

Method used

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  • Method for preparing 2,7-dibromocarbazole

Examples

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Effect test

example 1

[0017] Add 40 g (0.128 mol) of 4,4′-dibromobiphenyl, 0.2 g (1.32 mmol) of ferrous sulfate and 80 mL of 1,2-dichloroethane into a 250 mL three-necked flask, and slowly raise the temperature to 1 , 2-dichloroethane began to reflux, and 50 mL (0.25 mol) of 5 mol / L dilute nitric acid was slowly added dropwise to the reaction flask, and the temperature of the system was maintained at 80 °C for 2 h. No raw materials were detected by HPLC. Cool the reaction solution to room temperature, separate the layers, collect the organic phase in the lower layer, extract the aqueous phase once with 10 mL 1,2-dichloroethane, combine the organic phases, and recover 1,2-dichloroethane by distillation under reduced pressure to obtain crude product. Add methanol to the crude product, stir and heat until the solids are completely dissolved. After natural cooling, crystals are precipitated, filtered under reduced pressure, and dried in vacuo to obtain 42.4 g of 2-nitro-4,4'-dibromobiphenyl light yello...

example 2

[0020] Add 40 g (0.128 mol) of 4,4′-dibromobiphenyl, 0.24 g (1.8 mmol) of aluminum trichloride and 80 mL of 1,2-dichloroethane into a 250 mL three-necked flask, and slowly heat up to 1,2-Dichloroethane began to reflux, and 44 mL (0.22 mol) of 5 mol / L dilute nitric acid was slowly added dropwise to the reaction flask, and the temperature of the system was maintained at 82 °C for 2.5 h. No raw materials were detected by HPLC. Cool the reaction solution to room temperature, separate the layers, collect the organic phase in the lower layer, extract the aqueous phase once with 10 mL 1,2-dichloroethane, combine the organic phases, and recover 1,2-dichloroethane by distillation under reduced pressure to obtain crude product. Add methanol to the crude product, stir and heat until the solids are completely dissolved, and crystals precipitate after natural cooling, vacuum filtration under reduced pressure, and vacuum drying to obtain 41.9 g of 2-nitro-4,4'-dibromobiphenyl light yellow p...

example 3

[0023] Add 40 g (0.128 mol) of 4,4′-dibromobiphenyl, 0.32 g (1.97 mmol) of ferric chloride and 80 mL of 1,2-dichloroethane into a 250 mL three-necked flask, and slowly heat up to 1,2-Dichloroethane began to reflux, and 40 mL (0.2 mol) of 5 mol / L dilute nitric acid was slowly added dropwise to the reaction flask, and the temperature of the system was maintained at 84 °C for 3 h. No raw materials were detected by HPLC. Cool the reaction solution to room temperature, separate the layers, collect the organic phase in the lower layer, extract the aqueous phase once with 10 mL 1,2-dichloroethane, combine the organic phases, and recover 1,2-dichloroethane by distillation under reduced pressure to obtain crude product. Add methanol to the crude product, stir and heat until the solids are completely dissolved, and crystals precipitate after natural cooling, vacuum filtration under reduced pressure, and vacuum drying to obtain 42.7 g of 2-nitro-4,4'-dibromobiphenyl light yellow powder, ...

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Abstract

The invention discloses a method for preparing 2,7-dibromocarbazole, and belongs to the field of organic chemical synthesis. The method comprises the following steps: 2-nitro-4,4'-dibromobiphenyl is prepared by nitration reaction by taking 4,4'-dibromobiphenyl as a raw material, 1, 2-dichloroethane as a solvent, aluminum salt or iron salt as a catalyst and dilute nitric acid as a nitration reagent; and then, the oxygen closed ring of 2-nitro-4,4'-dibromobiphenyl is removed by taking dichlormethane as a solvent and one of 2-diphenylphosphine-biphenyl,tri(o-tolyl)phosphine or diphenyl-2-pyridylphosphine as a deoxidizer to obtain 2,7-dibromocarbazole. The reaction condition is mild and controllable, the cost is low, the operation is simple and the yield is high. The prepared 2,7-dibromocarbazole can be applied to the field of organic photoelectric materials and medicaments and is an important intermediate for carbazole photoelectric materials, medicaments and pesticides.

Description

technical field [0001] The invention relates to a preparation method of 2,7-dibromocarbazole, which belongs to the field of organic chemical synthesis. Background technique [0002] Carbazole and its derivatives are a class of heterocyclic aromatic compounds with large π-electron conjugated system and strong intramolecular electron transfer characteristics, excellent photoelectric properties, and are widely used in pigments, dyes, spices, medicines and pesticides, etc. field. [0003] 2,7-Dibromocarbazole is an important organic chemical intermediate, which can be used to further synthesize organic electroluminescent materials for new generation displays and hole transport materials, luminescent materials and new pesticides in organic polymer solar cells and medicine etc. [0004] There are many literature methods for the synthesis of 2,7-dibromocarbazole, in which the oxygen on the intermediate 2-nitro-4,4'-dibromobiphenyl nitro is removed by using the deoxidizer tripheny...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D209/88
Inventor 王福玲杨振强蒋卫鹏李江涛杨瑞娜曲凤波周铎
Owner PUYANG HUICHENG ELECTRONICS MATERIAL
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