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Synthesis method of 9H-carbazole-2-boronic acid pinacol ester by direct C-H boronation of carbazole C2 site

A synthesis method, pinacol ester technology, applied in the field of organic synthesis of carbazole derivatives, can solve the problems of high difficulty in later stage purification, complicated production steps, low utilization rate of atoms, etc., and achieve easy industrial production and low production cost , The effect of high atom utilization

Pending Publication Date: 2021-12-17
SINOSTEEL NANJING NEW MATERIALS RES INST CO LTD
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  • Abstract
  • Description
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  • Application Information

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Problems solved by technology

[0010] The object of the present invention is to provide a kind of synthetic method of the 9H-carbazole-2-boronic acid pinacol ester of a kind of carbazole C2 position direct C-H boration, and it can solve the complex production steps existing in the prior art, atom utilization rate is low, Technical problems of high production cost and high difficulty in later stage purification

Method used

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  • Synthesis method of 9H-carbazole-2-boronic acid pinacol ester by direct C-H boronation of carbazole C2 site
  • Synthesis method of 9H-carbazole-2-boronic acid pinacol ester by direct C-H boronation of carbazole C2 site
  • Synthesis method of 9H-carbazole-2-boronic acid pinacol ester by direct C-H boronation of carbazole C2 site

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036] Example 1: Synthesis Method of 9H-Carbazole-2-Borate Synthesis

[0037] The synthetic step includes: 50.7 g of carbazole (99%, 0.3 mol), 86.1 g of trifluoroacetate (99%, 0.6 mol), 2.0g [IR (OME) [IR (OME) under nitrogen protection (COD)] 2 (99%, 3 mmol), 0.6 g of ligand L1 (99%, 3 mmol), 23.0 g of alkali Base1 (99%, 0.15 mol) and 300 ml of tetrahydrofuran; the feed is completed, temperature rise to 50 ° C, stirring speed 350 rpm, insulation reaction for 12 hours After the CH boron reaction; after the reaction, water quenching reaction is added, the cooling room temperature filter, the liquid-reduced pressure distillation recovered solvent, petroleum ether crystals, to obtain 75.6 g of 9H-carbazole-2-boric acid-band The content was 99.5%, and the yield was 86.0%. The nervous resonance spectrum of 9H-carbazole-2-boronic acid frequency prepared by the present embodiment is like figure 1 Distance 1 H NMR (400MHz, CDCL 3 : δ = 1.40 (S, 12H), 7.23 (t, j = 7.8 Hz, 1H), 7.39 (D, J ...

Embodiment 2

[0038] Example 2: Synthesis of 9H-carbazole-2-boronic acid-frequency synthesis

[0039] The synthetic step includes: 50.7 g of carbazole (99%, 0.3 mol), 172.2 g of trifluoroacetate (99%, 1.2 mol), 2.0 g of [IR (OME) (COD)] 2 (99%, 3mmol), 1.04 g of ligand L2 (99%, 3 mmol), 23.0 g of alkali base1 (99%, 0.15 mol) and 300 ml of tetrahydrofuran; the feeding is 250 rpm, stirring speed 350 rpm, insulation reaction for 24 hours After the CH boron reaction; after the reaction, water quenching reaction is added, the cooling room temperature is filtered, the liquid is evaporated and evaporated. The content was 99.3%, and the yield was 88.9%.

Embodiment 3

[0040] Example 3: Synthesis of 9H-carbazole-2-boronic acid-frequency synthesis

[0041] The synthetic step comprises: 50.7 g of carbazole (99%, 0.3 mol), 129.2 g of trifluoroacetate (99%, 0.9 mol), 2.0 g of [IR (COD) CL] 2 (99%, 3 mmol), 0.6 g of ligand L1 (99%, 3 mmol), 21.7 g of alkali base2 (99%, 0.15 mol) and 600 ml of cyclopentyl ether; the feed was bonded, heated to 80 ° C, stirring the speed of 350 rpm, The incubation reaction was 24 hours, and the CH boron reaction was performed; after the reaction was completed, water quenched reaction was added, and the cooling room temperature was filtered, the liquid-reduced pressure distillation recovered solvent, the petroleum ether crystal obtained 74.4 g of 9H-carbazole-2-boric acid frequency Which alkoxide, a content of 99.6%, a yield of 84.6%.

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Abstract

The invention discloses a synthesis method of 9H-carbazole-2-boronic acid pinacol ester by direct C-H boronation of carbazole C2 site, which comprises the following steps: carrying out C-H boronation reaction on carbazole, ethyl trifluoroacetate and bis(pinacolato) diboron under the action of a catalyst, a ligand and alkali, and synthesizing the 9H-carbazole-2-boronic acid pinacol ester in one step by a one-pot method. According to the synthesis method of 9H-carbazole-2-boronic acid pinacol ester, phenanthroline derivatives are used as ligands, have a strong chelation effect and large steric hindrance and are coordinated with an iridium catalyst to enhance the selectivity of meta-position boronation, and ethyl trifluoroacetate is adopted to protect N-H bonds so as to synthesize 9H-carbazole-2-boronic acid pinacol ester in a meta-position guiding manner, the 9H-carbazole-2-boronic acid pinacol ester product is synthesized through a one-pot method by using carbazole as a raw material and catalyzing a carbazole C2-site C-H direct boronation reaction through iridium, the adopted raw materials are easy to obtain, post-treatment purification is simple, the synthesis route is simple, reaction conditions are mild, the production cost is low, and the reaction yield is high.

Description

Technical field [0001] The present invention belongs to the technical field of organic synthesis carbazole derivatives, especially pinacol ester synthesis method relates to a carbazole-C2 position directly C-H boronated 9H- carbazol-2-boronic acid. Background technique [0002] Carbazole derivatives having a large π electron conjugated system protruding nature, the strong intermolecular electron transfer properties, strong hole transporting ability and the like, widely used in medicine, dyes, pesticides and organic photovoltaic material. Carbazole boronic acid (ester) is a borated derivative having high stability, low toxicity carbazole, active natural products, pharmaceutical and organic materials science construct plays a key role. Pinacol ester 9H- carbazol-2-boronic acid as an important class of carbazole-C2 position boronic acid (ester) derivative, may have a larger conjugated system constructed by flash Suzuki coupling reaction intermediate carbazole derivative . Therefore,...

Claims

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Application Information

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IPC IPC(8): C07F5/04
CPCC07F5/04
Inventor 杨修光裴晓东骆艳华朱叶峰吴忠凯张玲张倩倩
Owner SINOSTEEL NANJING NEW MATERIALS RES INST CO LTD
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