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Aromatic diboron ester convenient synthesis method suitable for large-scale production

A technology for the synthesis of aromatic diboronic esters and methods, which is applied in the field of convenient synthesis of aromatic diboronic esters, can solve the problems of complicated operation, long purification time, labor consumption, etc., and achieve improved purification efficiency, simple synthetic methods, and reduced labor Effect

Inactive Publication Date: 2017-02-15
HUANGHE S & T COLLEGE
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  • Description
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Problems solved by technology

At present, the synthesis and preparation method of aromatic diboronic acid pinacol ester generally reacts under the catalysis of metal palladium, and then purifies the double boron ester by means of column chromatography. The yield is low (generally only up to 70%). At the same time, due to the need for purification by column chromatography, a large amount of solvent and silica gel will be wasted, and the purification time will be longer, resulting in higher production costs and limiting the expansion of production scale; At the same time, a lot of waste silica gel will be produced during the synthesis process, which is not conducive to environmental protection.

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  • Aromatic diboron ester convenient synthesis method suitable for large-scale production
  • Aromatic diboron ester convenient synthesis method suitable for large-scale production
  • Aromatic diboron ester convenient synthesis method suitable for large-scale production

Examples

Experimental program
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Effect test

Embodiment 1

[0019] Synthesis of 1,4-benzenediboronic acid pinacol diester (compound Ⅰ, chemical structure see figure 1 )

[0020] Its synthesis method is as follows:

[0021] Measure 2,4 dibromobenzene (500mg, 1.0eq), bis(pinacolate) diboron (1.2g, 2.0eq), PdCl 2 (Ph 3 ) 2 (100mg, 6.2%), KOAc (1.3g, 6.3eq), add them together into a 50ml three-neck flask, replace with nitrogen for 3 times, add 10ml of freshly distilled dioxane, reflux reaction (temperature 90~100℃) After 24h, stop reaction, obtain organic product;

[0022] Spin to dry the solvent, then add 60ml of ethyl acetate, ultrasonically dissolve the organic product, filter through diatomaceous earth, wash the diatomite with 10ml of ethyl acetate, then spin dry the ethyl acetate, add 10ml of petroleum ether, heat it with a hair dryer to promote dissolution, set overnight in the refrigerator; the next day, the solid was filtered by suction and dried in vacuo to obtain 660 mg of the product, yield: 93.6%. 1 H NMR (400 MHz, CDCl ...

Embodiment 2

[0025] Synthesis of 1,4 diboronic acid pinacol diester-2,5-tetrahydropyranylbenzene (compound Ⅱ, chemical structure see image 3 ).

[0026] Its synthesis method is as follows:

[0027] 1) Synthesis of 1,4-dibromo-2,5-dimethoxybenzene:

[0028] Add 20.0g (0.145mol, 1.0eq) of hydroquinone dimethyl ether and 55ml of glacial acetic acid into a 250ml reaction bottle, dissolve with ultrasonic; add 15ml of Br 2 (0.290mol, 2.0eq) and 15ml of glacial acetic acid solution, drop it after 1.5 hours, stir at room temperature for 2.5 hours; put it in the upper layer of the refrigerator to cool down to below 10°C (do not let the acetic acid solidify) and filter it; and wash the filter cake with petroleum ether , a white solid was obtained, which weighed 35.6 g after vacuum drying, and the yield was 83.6%. 1 H NMR (400 MHz, CDCl 3 ) δ 7.11 (s, 2H), 3.85 (s, 6H).

[0029] 2) Synthesis of 1,4-dibromohydroquinone:

[0030] In a 100ml single-necked bottle, add 7.1g (24.2mmol, 1.0eq) of 1,4...

Embodiment 3

[0037] Synthesis of 2,7 diboronic acid pinacol diester carbazole (compound Ⅲ, chemical structure see Figure 5 ).

[0038] Its synthesis method is as follows:

[0039] 500mg (1.55mmol, 1.0eq) of 2,7-dibromocarbazole, 980mg (3.86mmol, 2.5eq) of bis(pinacolate) diboron, PdCl 2 (PPh 3 ) 2 Add 100mg (0.142mmol, 0.09eq) and 1.0g (10.2mmol, 6.6eq) of KOAc into a 100ml three-neck flask, replace nitrogen three times, add 50ml of freshly distilled toluene, react at 85°C for 36h, then cool down to terminate the reaction. The reaction solution was filtered through celite, and the celite was washed with ethyl acetate, the ethyl acetate was spin-dried, and recrystallized with petroleum ether or n-hexane (for column chromatography, petroleum ether / ethyl acetate=10 / 1 eluent) to obtain 500 mg of a colorless product with a yield of 76.9%. H NMR (400 MHz, CDCl 3 ) δ 8.10 (d, J = 7.8 Hz, 2H), 8.04 (s, 1H), 7.93 (s, 2H), 7.68(d, J = 7.8 Hz, 2H), 1.38(s, 24H).

[0040] For the specific s...

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Abstract

The invention discloses an aromatic diboron ester convenient synthesis method suitable for large-scale production. A bibromo substrate serves as the raw material, and a metal catalyst and a reaction reagent are added under participation of alkali and bis(pinacolato)diboron for a coupling reaction, wherein reaction temperature is 70-100 DEG C, and the molar ratio of bis(pinacolato)diboron to the bibromo substrate is 1:10-10:1; after the reaction ends, diatomite is used for filtering, an organic solvent is removed, then re-crystallization and extraction are conducted, and a finished aromatic diboron ester product is obtained. The synthesis method is simple, production cost is low, and by-products, such as waste silica gel and excessive waste solvents, which are not environmentally friendly are not generated. The product is purified through the re-crystallization method, the product only needs to be crystallized and stay overnight at low temperature, a large number of solvents do not need to be consumed, workloads are reduced, purification efficiency of the product is also improved, large-scale industrial production is facilitated, and the reaction yield can reach as high as 93.6%.

Description

technical field [0001] The invention relates to the synthesis technology of organic intermediates used in the fields of medicine and materials, in particular to a convenient synthesis method of aromatic diboronic esters suitable for large-scale production. Background technique [0002] Including 1,4 phenylenediboronic acid pinacol diester, 2,5 bis(tetrahydro-2H-pyran-2oxy) 1,4 phenylenediboronic acid pinacol diester and 2,7-bis(boronic acid pinacol diester As important reaction intermediates, aromatic diboronic acid (pinacol ester) and carbazole, etc., have important application value in the fields of medicine, chemical industry, and materials. At present, the synthesis and preparation method of aromatic diboronic acid pinacol ester generally reacts under the catalysis of metal palladium, and then purifies the double boron ester by means of column chromatography. The yield is low (generally only up to 70%). At the same time, due to the need for purification by column chroma...

Claims

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Application Information

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IPC IPC(8): C07F5/02
CPCC07F5/02
Inventor 康红卫李艳春冀明明
Owner HUANGHE S & T COLLEGE
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