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Method for preparing 2,3-dihydrobenzofuran formaldehyde

A technology of furan formaldehyde and dihydroxybenzaldehyde, applied in the direction of organic chemistry and the like, can solve problems such as complex synthesis process and harsh conditions

Inactive Publication Date: 2017-06-13
上海启雁实业有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The current method for synthesizing 2,3-dihydrobenzofuran aldehyde is to introduce a formyl group on the benzofuran ring, either using highly toxic reagents or harsh conditions
Moreover, the synthesis process of the 2,3-dihydrobenzofuran ring itself is relatively complicated

Method used

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  • Method for preparing 2,3-dihydrobenzofuran formaldehyde

Examples

Experimental program
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Effect test

Embodiment 1

[0023] A method for preparing 2,3-dihydrobenzofuran carbaldehyde, characterized in that it comprises the steps of:

[0024] 1), take p-Hydroxybenzaldehyde as raw material, obtain 3-bromo-4-hydroxyl-benzaldehyde after bromination,

[0025] 2), docking 3-bromo-4-hydroxy-benzaldehyde with 1-bromo-2 chloroethane under the action of organic solvent DMF and potassium carbonate to obtain intermediate I, the reaction temperature is 40°C-50°C,

[0026] 3), the aldehyde group of the above-mentioned intermediate I reacts with ethylene glycol in the organic solvent toluene under the catalysis of p-toluenesulfonic acid to form the acetal intermediate II, and the reaction temperature is 90-100°C;

[0027] 4), Intermediate II uses methyl THF as a solvent, and undergoes self-cyclization under the action of magnesium strips to form 2,3-dihydrobenzofuran intermediate III. Reaction temperature: 40-50°C;

[0028] 5) The acetal protection of intermediate III is removed under acidic conditions to ...

Embodiment 2

[0032] A method for preparing 2,3-dihydrobenzofuran carbaldehyde, characterized in that it comprises the steps of:

[0033] 1), take m-hydroxybenzaldehyde as raw material, obtain 2-bromo-3-hydroxyl-benzaldehyde after bromination,

[0034] 2), docking 2-bromo-3-hydroxy-benzaldehyde with 1,2-dibromoethane under the action of organic solvent acetonitrile and sodium carbonate to obtain intermediate I, the reaction temperature is 65°C-80°C,

[0035] 3), the aldehyde group of the above-mentioned intermediate I reacts with ethylene glycol in the organic solvent xylene under the catalysis of sulfuric acid to form the acetal intermediate II, and the reaction temperature is 110-125°C;

[0036] 4) Intermediate II uses diethyl ether and THF as solvents, and undergoes self-cyclization under the action of butyllithium to form 2,3-dihydrobenzofuran intermediate III. Reaction temperature: -20~0°C;

[0037] 5) The acetal protection of intermediate III is removed under the acidic condition of ...

Embodiment 3

[0041] A method for preparing 2,3-dihydrobenzofuran carbaldehyde, characterized in that it comprises the steps of:

[0042] 1), take p-Hydroxybenzaldehyde as raw material, obtain 3-bromo-4-hydroxyl-benzaldehyde after bromination,

[0043] 2), under the action of organic solvent DMF and potassium carbonate, 3-bromo-4-hydroxy-benzaldehyde is docked with bromoethane, and then brominated to obtain intermediate I, the reaction temperature is 80°C-90°C,

[0044] 3), the aldehyde group of the above-mentioned intermediate I reacts with ethylene glycol in the organic solvent toluene and xylene under the catalysis of p-toluenesulfonic acid to form the acetal intermediate II, and the reaction temperature is 130-140°C;

[0045] 4), Intermediate II uses methyl THF as a solvent, cyclizes itself under the action of magnesium strips to form 2,3-dihydrobenzofuran intermediate III, reaction temperature: 60-70°C;

[0046] 5) The acetal protection of intermediate III is removed under acidic cond...

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Abstract

The invention discloses a method for preparing 2,3-dihydrobenzofuran formaldehyde, comprising the following steps: dihydroxy benzaldehyde which is used as a raw material is brominated to obtain benzaldehyde containing bromine and hydroxyl group; after halogenation of ethene, halogenated ethene and the above benzaldehyde are in butt joint under the action of an organic solvent and alkali so as to obtain an intermediate I; an aldehyde group of the above intermediate I reacts with glycol in an organic solvent and under acid catalysis to generate an intermediate II; the intermediate II undergoes cyclization under the action of magnesium rod or butyl lithium to form an intermediate III; and the intermediate III undergoes acetal deprotection under the acidic condition so as to obtain 2,3-dihydrobenzofuran formaldehyde. The invention has the following advantages: 2,3-dihydrobenzofuran is not used as the raw material; cheap and easily-available dihydroxy benzaldehyde is used as the raw material for synthesis of the important drug intermediate 2,3-dihydrobenzofuran aldehyde; use of toxic reagents such as phosphorous oxychloride is avoided; and reaction condition is mild.

Description

technical field [0001] The invention relates to the technical field of chemical synthesis, in particular to a method for preparing 2,3-dihydrobenzofuran carboxaldehyde. Background technique [0002] The 2,3-dihydrobenzofuran structure is a commonly used structure in drug molecules, such as the melatonin receptor agonists Ramelteon and Tasimelteon. [0003] [0004] 2,3-Dihydrobenzofuran aldehyde is an important synthetic raw material for the synthesis of the above drugs. The current methods for synthesizing 2,3-dihydrobenzofuran aldehyde are to introduce formyl groups on the benzofuran ring, either using highly toxic reagents or harsh conditions. Moreover, the synthesis process of the 2,3-dihydrobenzofuran ring itself is relatively complicated. . Contents of the invention [0005] The object of the present invention is to provide a method for preparing 2,3-dihydrobenzofuran carboxaldehyde without using 2,3-dihydrobenzofuran as a raw material in order to make up for t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D307/80
CPCC07D307/80
Inventor 王奇
Owner 上海启雁实业有限公司
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