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Method for synthesizing 1-carbazole-boronic acid pinacol ester through ortho-oriented boronation of amide

A technology for the synthesis of pinacol esters and compounds, which is applied in the field of carbazole derivatives synthesis, can solve the problems of complicated operation, low product yield, difficult purification and the like, and achieves avoiding reaction conditions, high product yield and mild reaction conditions. Effect

Pending Publication Date: 2021-12-24
SINOSTEEL NANJING NEW MATERIALS RES INST CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0015] The object of the present invention is to provide a kind of method of amide ortho-directed boration synthesis 1-carbazole-boric acid pinacol ester, which can solve the problem of using noble metal catalyst, Technical problems such as complex operation, low product yield, and difficulty in purification

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  • Method for synthesizing 1-carbazole-boronic acid pinacol ester through ortho-oriented boronation of amide
  • Method for synthesizing 1-carbazole-boronic acid pinacol ester through ortho-oriented boronation of amide
  • Method for synthesizing 1-carbazole-boronic acid pinacol ester through ortho-oriented boronation of amide

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Experimental program
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Effect test

Embodiment 1

[0041] Embodiment 1: A kind of synthetic method of 1-carbazole-boronic acid pinacol ester

[0042] Step comprises: (1) under the condition of 0 ℃, add the carbazole (99%, 0.2mol) of 33.4g, the catalyst DMAP (98%, 0.04mol) of 4.9g, the triethylamine of 40.5g ( 98%, 0.4mol), 400mL of dichloromethane, after the system was stabilized at 0°C, 100mL of pivaloyl chloride (98%, 29.5g, 0.24mol) in dichloromethane was added dropwise; React at room temperature for 6 hours. After the reaction, add 100 mL of water to the organic layer and wash three times. Dichloromethane is recovered by distillation under reduced pressure. Concentrate and crystallize to obtain 48.5 g of N-pivaloyl carbazole as a white solid N-acyl carbazole intermediate, with a yield of 96.5%. (2) under the protection of nitrogen, add the dichloromethane of the N-pivaloyl carbazole (99%, 0.193mol) of synthesis 48.5g, 300mL in the reaction flask, drop boron tribromide (99%, 60.0g, 0.24mol) of dichloromethane solution 100m...

Embodiment 2

[0044] Embodiment 2: A kind of synthetic method of 1-carbazole-boronic acid pinacol ester

[0045] The steps include: (1) at -10°C, add 33.4g of carbazole (99%, 0.2mol), 4.9g of catalyst DMAP (98%, 0.04mol), 600mL of tetrahydrofuran to the reaction flask, and stir for 30 minutes Add 16.0g of NaH (60%, 0.4mol) again, after the temperature of the system is stable, rise to room temperature and react for 1 hour, then add dropwise 200mL of tetrahydrofuran solution of benzoyl chloride (98%, 43.0g, 0.30mol); , warmed up to room temperature and reacted for 4 hours; after the reaction, the organic layer was washed once with saturated brine and once with water, and tetrahydrofuran was recovered by distillation under reduced pressure, concentrated and crystallized to obtain a white solid N-acyl carbazole intermediate N-benzoyl carbazole 50.3 g, yield 92.7%;

[0046] (2) Under the protection of nitrogen, add 50.3g of synthesized N-benzoylcarbazole (99%, 0.185mol), 300mL of dichloromethan...

Embodiment 3

[0047] Embodiment 3: A kind of synthetic method of 1-carbazole-boronic acid pinacol ester

[0048] Step comprises: (1) under the condition of 0 ℃, add the carbazole (99%, 0.2mol) of 33.4g, the catalyst DMAP (98%, 0.04mol) of 4.9g, the triethylamine of 60.8g ( 98%, 0.6mol), 400mL tetrahydrofuran, stirred for 30 minutes, added dropwise 100mL of di-tert-butyl dicarbonate (98%, 49.0g, 0.22mol) tetrahydrofuran solution; after feeding, stirred for 30 minutes, and reacted at room temperature for 6 hours; After the reaction, the organic layer was washed once with saturated brine and once with water, and tetrahydrofuran was recovered by distillation under reduced pressure, and 100 mL of n-hexane was added for recrystallization to obtain 51.8 g of N-tert-butoxycarbonyl carbazole as a white solid N-acyl carbazole intermediate. Rate 96.8%;

[0049] (2) Under nitrogen protection, add 51.8g of synthesized N-tert-butoxycarbonylcarbazole (99%, 0.194mol), 300mL of dichloromethane in the react...

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Abstract

The invention discloses a method for synthesizing 1-carbazole-boronic acid pinacol ester through ortho-oriented boronation of amide. The method comprises the following steps: (1) carrying out amidation reaction on carbazole and an amidation reagent under the action of a catalyst and alkali to obtain an N-acyl carbazole intermediate I; and (2) adding boron trihalide (BX3) and an organic solvent, carrying out boronation reaction, then adding pinacol and an alkali, carrying out esterification and deprotection reaction to obtain the 1-carbazole-boronic acid pinacol ester. According to the synthesis method disclosed by the invention, carbazole which is cheap and easy to obtain is used as a raw material, and the 1-carbazole-boronic acid pinacol ester is prepared by creatively adopting a carbazole 9-site N-acylation and oriented ortho-boronation method, so that not only is the influence of carbazole N-H on a catalytic reaction avoided, but also a strong oriented effect is achieved, the selectivity of oriented electrophilic boronation of a carbazole C1 site is increased, a guiding group is easy to remove in situ, a lithium reagent and transition noble metal iridium and palladium catalysts are not used, the reaction conditions are mild, and post-treatment purification is simple.

Description

technical field [0001] The invention relates to the technical field of synthesis of carbazole derivatives, in particular to a method for synthesizing 1-carbazole-boronic acid pinacol ester by amide ortho-directed boration. Background technique [0002] Carbazoles are a class of important nitrogen-containing heterocyclic aromatic compounds with outstanding properties such as large π-conjugated electron systems, strong intramolecular electron transfer properties, and strong hole transport capabilities. They are widely used in medicine, dyes, pesticides, and organic optoelectronic materials. Wide range of applications. At the same time, organoboron reagents, especially arylboronic acids (esters), as a class of important organic synthesis intermediates with the advantages of high stability, low toxicity, and easy operation, play an important role in the construction of active natural products, medicines, and organic materials science. It plays a key role, so it has a wide range...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07F5/02
CPCC07F5/025
Inventor 杨修光裴晓东骆艳华朱叶峰吴忠凯申保金张玲张倩倩
Owner SINOSTEEL NANJING NEW MATERIALS RES INST CO LTD
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