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Preparation method of 1-nitro-2-ethyl-4-fluorobenzene

A technology of nitrobenzene and nitro, which is applied in the field of preparation of 1-nitro-2-ethyl-4-fluorobenzene, can solve the problems of heat accumulation, high cost of reagents, difficult purification of products, etc., and achieve the utilization of raw materials The effect of improving the efficiency, reducing the production cost and benefiting the separation and purification

Active Publication Date: 2020-02-04
ACCELA CHEMBIO CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Among them, 1-nitro-2-ethyl-4-fluorobenzene is an important part of p-fluoronitrobenzene compounds, and its conventional synthetic route is to use 2-nitro-5-fluoroaniline as a raw material. The two-step reaction of diazotization and Negishi coupling can obtain the target product, but the cost of reagents used in this synthetic route is high, the product yield is low, and the safety of the process route is not good; especially the Negishi coupling reaction in the second step, organic Coupling reaction of zinc reagent with halogenated aromatic hydrocarbon under the catalysis of nickel or palladium complex, the catalyst is expensive, and there is obvious accumulation and exothermic phenomenon in the reaction process, which is dangerous to a certain extent. It has extremely high requirements, and the final product is difficult to purify. It is only suitable for small-scale preparation regardless of cost in the laboratory. It cannot achieve kilogram-level amplification, and it is even more difficult to achieve industrial scale production.

Method used

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  • Preparation method of 1-nitro-2-ethyl-4-fluorobenzene

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Experimental program
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Effect test

Embodiment 1

[0094] This embodiment provides a preparation method of 1-nitro-2-ethyl-4-fluorobenzene, which specifically includes the following steps:

[0095] (1) Add 2330g of fuming nitric acid to the reaction bottle, add 362g of m-fluoroacetophenone dropwise at -10°C under controlled temperature, stir and react at -8°C for 3h after the addition, and determine whether the end point of the reaction is reached by sampling and testing HPLC After reaching the end point, slowly pour the reaction solution into ice water to quench the reaction, stir at 3°C ​​for 1 hour, filter and collect the solid phase, wash the filter cake with water, and dry it in vacuum to obtain 360 g of the product 2-nitro-5-fluoroacetophenone , the yield was 75%, and the purity was 98.5%.

[0096] Product test: 1 H-NMR (300MHz, CDCl 3 ): δ8.25(m, 1H), 7.25(m, 1H), 7.10(d, 1H), 2.57(s, 3H).

[0097] (2) 360 g of 2-nitro-5-fluoroacetophenone obtained in step (1), 1.6 L of tetrahydrofuran and 0.5 L of anhydrous methanol...

Embodiment 2

[0103] This embodiment provides a preparation method of 1-nitro-2-ethyl-4-fluorobenzene, which specifically includes the following steps:

[0104] (1) Add 650g of fuming nitric acid to the reaction bottle, add 100g of m-fluoroacetophenone dropwise at -10°C under controlled temperature, stir and react at -10°C for 3h after the dropwise addition, and judge whether the end point of the reaction is reached by sampling and testing HPLC After reaching the end point, slowly pour the reaction solution into ice water to quench the reaction, stir at 0°C for 1 hour, filter and collect the solid phase, wash the filter cake with water, and dry it in vacuum to obtain 105 g of the product 2-nitro-5-fluoroacetophenone , the yield was 79%, and the purity was 98.4%.

[0105] Product test: 1 H-NMR (300MHz, CDCl 3 ): δ8.25(m, 1H), 7.25(m, 1H), 7.10(d, 1H), 2.57(s, 3H).

[0106] (2) 105 g of 2-nitro-5-fluoroacetophenone obtained in step (1), 0.5 L of tetrahydrofuran and 0.15 L of anhydrous meth...

Embodiment 3

[0114] This embodiment provides a preparation method of 1-nitro-2-ethyl-4-fluorobenzene, which specifically includes the following steps:

[0115] (1) Add 1500g of fuming nitric acid to the reaction bottle, add 300g of m-fluoroacetophenone dropwise at -15°C under controlled temperature, stir and react at -15°C for 5h after the dropwise addition, and judge whether the end point of the reaction is reached by sampling and testing HPLC After reaching the end point, slowly pour the reaction solution into ice water to quench the reaction, stir at 0°C for 30 minutes, filter and collect the solid phase, wash the filter cake with water, and dry it in vacuum to obtain 310 g of the product 2-nitro-5-fluoroacetophenone. The yield was 78%, and the purity was 98.7%.

[0116] Product test: 1 H-NMR (300MHz, CDCl 3 ): δ8.25(m, 1H), 7.25(m, 1H), 7.10(d, 1H), 2.57(s, 3H).

[0117](2) Add 310 g of 2-nitro-5-fluoroacetophenone obtained in step (1), 1.1 L of tetrahydrofuran and 0.3 L of anhydrou...

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Abstract

The invention provides a preparation method of 1-nitro-2-ethyl-4-fluorobenzene. The preparation method comprises the following steps: (1) carrying out a nitration reaction on m-fluoroacetophenone anda nitration reagent to obtain 2-nitro-5-fluoroacetophenone; (2) carrying out a reduction reaction on the 2-nitro-5-fluoroacetophenone and a reducing agent to obtain 4-fluoro-2-(1-hydroxyethyl)-1-nitrobenzene; (3) carrying out an iodination reaction on the 4-fluoro-2-(1-hydroxyethyl)-1-nitrobenzene to obtain 4-fluoro-2-(1-iodoethyl)-nitrobenzene; and (4) carrying out a reducing reaction on the 4-fluoro-2-(1-iodoethyl)-nitrobenzene with a reducing agent to obtain the 1-nitro-2-ethyl-4-fluorobenzene. The preparation method not only effectively improves the yield and purity of the product, but also has mild reaction conditions. The preparation process has high safety, raw material cost is low, and the preparation method is suitable for industrial amplification production and has a wide application prospect.

Description

technical field [0001] The invention belongs to the technical field of organic synthesis, and in particular relates to a preparation method of 1-nitro-2-ethyl-4-fluorobenzene. Background technique [0002] P-fluoronitrobenzene compounds are important intermediates in the preparation of medicines, pesticides, dyes and photosensitive materials, and are widely used in the synthesis of antibacterial western medicines and high-efficiency herbicides. Among them, 1-nitro-2-ethyl-4-fluorobenzene is an important part of p-fluoronitrobenzene compounds, and its conventional synthetic route is to use 2-nitro-5-fluoroaniline as a raw material. The two-step reaction of diazotization and Negishi coupling can obtain the target product, but the cost of reagents used in this synthetic route is high, the product yield is low, and the safety of the process route is not good; especially the Negishi coupling reaction in the second step, organic Coupling reaction of zinc reagent with halogenated ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C201/08C07C201/12C07C205/12C07C205/26C07C205/45
CPCC07C201/08C07C201/12C07C205/45C07C205/12C07C205/26C07C205/11C07C205/06C07C205/19
Inventor 刘洋薛多清吴勇陈立煌翟连华
Owner ACCELA CHEMBIO CO LTD
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