Preparation method of 2,5-dihydroxybenzaldehyde

A technology of dihydroxybenzaldehyde and dimethoxybenzaldehyde, which is applied in the field of preparation of important intermediate 2,5-dihydroxybenzaldehyde, can solve the problem of low cost, achieve mild preparation conditions, strong industrial application value, The effect of simple process

Inactive Publication Date: 2019-10-15
JIANGXI RV PHARMA
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  • Abstract
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  • Claims
  • Application Information

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Problems solved by technology

Therefore, still lack a kind of preparation technology simple at present, cost is low, is

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  • Preparation method of 2,5-dihydroxybenzaldehyde

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Embodiment 1

[0014] 1) Synthesis of 2,5-dimethoxybromobenzene

[0015] Add 38.5g (278.6mmol) of terephthalic ether and 120g of N,N-dimethylformamide (DMF) to a 500ml four-necked flask. Stir mechanically at room temperature until it is completely dissolved. Cool down to 10℃ and add 45g slowly. (252.8mmol) The solution prepared by N-bromosuccinimide and N,N-dimethylformamide, drip in about 1 hour, react for 1 hour, slowly add 200ml of water to the reaction solution at room temperature, add Dichloroethane (100mL) was extracted twice, the organic layer was extracted with saturated brine (100mL), the organic layer was dried over anhydrous sodium sulfate overnight, filtered with suction, and the filtrate was evaporated to remove the solvent to obtain a brownish yellow liquid 2,5-dimethoxy Bromobenzene 49.3g.

[0016] 2) Synthesis of 2,5-Dimethoxybenzaldehyde

[0017] Add 7.5g (312.5mmol) of magnesium powder, 35g of tetrahydrofuran (THF) to a 500mL four-necked flask, under nitrogen protection, add 50g...

Embodiment 2

[0021] 1) Synthesis of 2,5-dimethoxybromobenzene

[0022] Add 38.5g (278.6mmol) terephthalic ether and 150g N,N-dimethylformamide to a 500ml four-necked flask, stir mechanically at room temperature until it is completely dissolved, and slowly add 49.6g (278.6mmol) dropwise to 10℃. ) The solution prepared by N-bromosuccinimide and N,N-dimethylformamide, drip in about 1 hour, react for 1 hour, slowly add 200ml of water to the reaction solution at room temperature, add dichloroethane Extraction with alkane (100 mL), extract the organic layer with saturated brine (100 mL), dry the organic layer with anhydrous sodium sulfate overnight, filter with suction, and rotate the filtrate to obtain 51 g of brown liquid.

[0023] 2) Synthesis of 2,5-Dimethoxybenzaldehyde

[0024] Add 11g (460mmol) of magnesium powder, 50g of tetrahydrofuran and nitrogen protection to a 500mL four-necked flask. Add 10 drops of a solution of 50g (230.3mmol) of 2,5-dimethoxybromobenzene and tetrahydrofuran under mech...

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Abstract

The invention provides a method for synthesizing 2,5-dihydroxybenzaldehyde. The method comprises the following steps: with p-dimethoxybenzene as a raw material, carrying out bromination reaction, Grignard reaction and demethylation reaction to obtain the 2,5-dihydroxybenzaldehyde. The preparation conditions are mild, the process is simple, and the industrial application value is high.

Description

Technical field [0001] The invention relates to a preparation method of 2,5-dihydroxybenzaldehyde, an important intermediate for preparing liquid crystal compounds. Background technique [0002] 2,5-Dihydroxybenzaldehyde is an important intermediate and has a wide range of uses in polymer liquid crystals and dyes. [0003] There is no specific literature report on the synthetic route for the preparation of 2,5-dihydroxybenzaldehyde. Therefore, there is currently a lack of a method for preparing 2,5-dihydroxybenzaldehyde with simple preparation process, low cost, and suitable for industrial scale-up. Summary of the invention [0004] The purpose of the present invention is to provide a method for preparing 2,5-dihydroxybenzaldehyde with mild conditions, simple operation, high yield and industrial application prospects. [0005] The preparation method of 2,5-dihydroxybenzaldehyde of the present invention includes the following steps: [0006] The first step of bromination reaction: usi...

Claims

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Application Information

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IPC IPC(8): C07C45/64C07C47/565
CPCC07C45/64C07C45/455C07C41/22C07C47/565C07C47/575C07C43/225
Inventor 徐步斌王仉华方贵
Owner JIANGXI RV PHARMA
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