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Preparation method of benzofuran-2-(3H)-ketone

A technology for benzofuran and phenol, applied in the field of preparation of benzofuran-2-one, can solve the problems of large amount of solvent, cumbersome post-processing process, unenvironmental process, etc., and achieves simple and easy-to-obtain raw materials and stable catalyst structure. , the effect of high industrial application value

Inactive Publication Date: 2020-02-14
DALIAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although the first method has a total yield of up to 87%, the highly toxic compound sodium cyanide, a large amount of alkali and acid are used in the reaction, and the process is not environmentally friendly, which greatly limits the industrialization of the method
The second method has a relatively complicated process, a large amount of solvent, and cumbersome post-reaction treatment, causing serious pollution, and the overall yield is not high, so it is not an ideal preparation route.
The third method has a total yield of 64%, but a large amount of solvent is used in the reaction, the post-treatment process is relatively cumbersome, and expensive catalysts are used, which hinders the further realization of industrialization of the method

Method used

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  • Preparation method of benzofuran-2-(3H)-ketone
  • Preparation method of benzofuran-2-(3H)-ketone
  • Preparation method of benzofuran-2-(3H)-ketone

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] The first step, synthesis of α-chloroacetic acid phenol ester

[0023] Weigh 2.00g of phenol and 2.40g of chloroacetyl chloride and add them into 50mL of dichloromethane, where the concentration of phenol is 0.5mol / L, then add 2.14g of triethylamine, cool down to -20°C, and react for 1h. After the end, add acid and Washed with saturated brine and post-treated to obtain 2.56 g of white solid with a yield of 70%. α-Chloroacetyl chloride 1 H-NMR spectrum as figure 1 as shown, 1 H NMR (500MHz, Chloroform-d) δ7.40(t, J=7.8Hz, 2H), 7.28(d, J=7.8Hz, 1H), 7.16–7.09(m, 2H), 4.31(s, 2H) .

[0024] The second step, synthesis of benzofuran-2-(3H)-one

[0025] Add 1.00g of α-phenol chloroacetate generated in the first step into 10ml of carbon tetrachloride, and dissolve in 0.04g of anhydrous AlCl 3 The Friedel-Crafts reaction occurred under the condition of 20° C., the reaction time was 3 h, and the yield was 83% as detected by TLC.

Embodiment 2

[0027] The first step, synthesis of α-chloroacetic acid phenol ester

[0028] Weigh 2.00g of phenol and 4.81g of chloroacetyl chloride and add them to 50mL of carbon tetrachloride, where the concentration of phenol is 1.0mol / L, add 4.73g of sodium phenoxide, cool down to 0°C, and react for 6h, then add acid and saturated salt After washing with water, 2.72 g of white solid was obtained after treatment, with a yield of 75.21%. α-Chloroacetyl chloride 1 H-NMR spectrum as figure 1 shown.

[0029] The second step, synthesis of benzofuran-2-(3H)-one

[0030] Add 1.00g of α-phenol chloroacetate generated in the first step into 10ml of dichloromethane, and react under the condition of 0.017g of p-toluenesulfonic acid, the reaction temperature is 60°C, and the reaction time is 8h. After TLC detection, the product The rate is 73.6%.

Embodiment 3

[0032] The first step, synthesis of α-chloroacetic acid phenol ester

[0033] Weigh 2.00g of phenol and 7.21g of chloroacetyl chloride and add them into 50mL of chloroform, where the concentration of phenol is 1.5mol / L, add 3.45g of sodium carbonate, heat up to 60°C, react for 4h, add acid and saturated saline to wash after completion, After working up, 2.64 g of white solid were obtained, the yield was 72.88%. α-Chloroacetyl chloride 1 H-NMR spectrum as figure 1 shown.

[0034] The second step, synthesis of benzofuran-2-(3H)-one

[0035] Add 1.00g of α-phenol chloroacetate generated in the first step into 10ml of dichloromethane, and a Friedel-Crafts reaction occurs under the condition of 0.16g of anhydrous ferric chloride, the reaction temperature is 80°C, and the reaction time is 12h. As detected by TLC, the yield was 78.6%.

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Abstract

The invention discloses a preparation method of benzofuran-2-(3H)-ketone, and belongs to the technical field of organic synthesis. Phenol serves as a raw material for esterification reaction with chloroacetyl chloride, the generated alpha-chloroacetic acid phenol ester performs a Friedel-Crafts reaction under the condition that acid serves as a catalyst and then subjected to cyclization to generate the benzofuran-2-(3H)-ketone. According to the preparation method of the benzofuran-2-(3H)-ketone, reaction pathways reported in existing literatures are greatly shortened, the raw material of phenol is simple and easy to obtain, the highly toxic compound of sodium cyanide and a large amount of alkali and acid do not need to be added, the reaction conditions of the method is mild, the reaction efficiency is high, the raw materials are simple and easy to obtain, the reaction cost is greatly lowered, the synthesis steps are greatly shortened, and high industrial application value is achieved.

Description

technical field [0001] The invention belongs to the technical field of organic synthesis, and relates to a preparation method of benzofuran-2-(3H)-one. Background technique [0002] As a fungicide, azoxystrobin has the advantages of wide bactericidal spectrum, increased disease resistance, improved stress resistance, delaying the aging of crops, long-lasting effect, high efficiency and safety, etc., because the original drug and compound of azoxystrobin have exceeded The patent is valid, and the domestic demand for its intermediate benzofuran-2-(3H)-one is increasing day by day. [0003] The common preparation methods of benzofuran-2-(3H)-ketone are: method one, take o-chlorobenzyl chloride as raw material, obtain product through cyanidation, hydrolysis and intramolecular esterification; method two, use cyclohexanone and Methyl dimethoxyacetate is obtained by condensation, cyclization and dehydrogenation as a raw material; Method 3, benzofuran-2-(3H )-ketones (EP, 1481959A...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D307/83
CPCC07D307/83
Inventor 孟庆伟宋博唐晓飞赵静喃
Owner DALIAN UNIV OF TECH
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