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Preparation method of benzofuran or indole

A technology of benzofuran and indole, which is applied in the field of organic synthesis, can solve problems such as large limitations, and achieve the effects of low environmental pollution, low reaction cost and high reaction efficiency

Inactive Publication Date: 2012-10-17
SUN YAT SEN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this type of reaction has relatively large limitations on the substrate, and is limited to benzofuran or indole substituted with benzyl or primary alkyl at the 2-position.

Method used

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  • Preparation method of benzofuran or indole
  • Preparation method of benzofuran or indole
  • Preparation method of benzofuran or indole

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] Synthesis of 2-Benzylbenzofuran

[0032] Add 1 part of benzaldehyde and 1 part of p-toluenesulfonylhydrazide successively into a beaker filled with methanol (the amount of methanol is 1 mL of methanol per 1 mmol of the reaction raw material), react at 60°C for 10 minutes, cool to room temperature, and filter with suction Remove solvent, the solid of gained is transferred in the Schlenk bottle, under the protection of nitrogen, add 1.1 parts of o-hydroxyphenylacetylene, 0.1 parts of cuprous bromide, 3 parts of lithium tert-butoxide and toluene (the concentration of control reaction is 1mmol / 5mL), after reacting at 80°C for 4 hours, the reaction solution was returned to room temperature and concentrated, and purified by column chromatography with petroleum ether as eluent to obtain 2-benzylbenzofuran with a yield of 89%. Its structure is shown in the following formula:

[0033]

[0034] The NMR data of the compound are as follows:

[0035] 1 H NMR (300 MHz, CDCl 3...

Embodiment 2

[0037] Synthesis of 2-(2-methylbenzyl)benzofuran

[0038]Add 1 part of o-toluene sulfonyl hydrazide and 1 part of o-toluenesulfonyl hydrazide successively in a beaker filled with methanol (the amount of methanol is 1 mL of methanol per 1 mmol of the reaction raw material), react at 60 ° C for 10 minutes and cool to room temperature , the solvent was removed by suction filtration, the resulting solid was transferred to a Schlenk bottle, and 1.1 parts of o-hydroxyphenylacetylene, 0.1 part of cuprous bromide, 3 parts of lithium tert-butoxide and dimethyl sulfoxide were added under nitrogen protection (The concentration of the reaction is controlled to be 1mol / 5mL). After reacting at 60°C for 12 hours, the reaction solution was returned to room temperature and then concentrated. Petroleum ether was used as the eluent for column chromatography purification to obtain 2-(2-methylbenzyl)benzene And furan, the yield is 92%. Its structure is shown in the following formula:

[0039] ...

Embodiment 3

[0043] Synthesis of 2-(2,6-dichlorobenzyl)benzofuran

[0044] Add 1 part of 2,6-dichlorobenzaldehyde and 1 part of p-toluenesulfonylhydrazide in sequence in a beaker filled with methanol (the amount of methanol is 1 mL of methanol per 1 mmol of the reaction raw material), and react at 60°C for 10 minutes Cool to room temperature, remove the solvent by suction filtration, transfer the resulting solid into a Schlenk bottle, add 1.1 parts of o-hydroxyphenylacetylene, 0.1 parts of cuprous bromide, 3 parts of lithium tert-butoxide and dimethyl 2-(2,6-di Chlorobenzyl) benzofuran, the yield is 81%. Its structure is shown in the following formula:

[0045]

[0046] The NMR data of the compound are as follows:

[0047] 1 H NMR (300 MHz, CDCl 3 ) δ 4.47 (s, 2H), 6.26 (s, 1H), 7.14-7.24 (m, 3H), 7.34-7.45 (m, 4H); 13 C NMR (75 MHz, CDCl 3 ) δ 31.0, 103.5, 111.2, 120.6, 122.7, 123.7, 128.5, 128.9, 133.5, 136.3, 154.9.

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Abstract

The invention discloses a convenient and efficient preparation method of benzofuran or indole. The preparation method comprises the following steps of: reacting various natural or non-natural aldehyde ketone with sulfonylhydrazine to obtain corresponding hydrazone; and reacting the hydrazone with substituted ortho-hydroxybenzene acetylene or substituted ortho-aminobenzene acetylene in a basic condition by using a copper compound as a catalyst in an organic solvent to obtain the derivative of benzofuran or indole. The method has wide substrate adaptability, can be used for synthesizing various benzofuran or indole compounds carrying different substituents, uses the copper compound with low price as a catalyst, has low price and easily available initial raw materials in the reaction, namely aldehyde ketone and ortho-hydroxybenzene acetylene or ortho-aminobenzene acetylene, as well as is convenient operation in the reaction process, and is suitable for large-scale synthesis.

Description

technical field [0001] The invention relates to the field of organic synthesis, in particular to a preparation method of benzofuran or indole. Background technique [0002] Benzofuran is the core structure of many biologically active natural products, and many synthetic drugs also contain such structural units. Indole and its derivatives not only widely exist in nature, but tryptophan, an essential amino acid for humans and animals, is also a derivative of indole. Therefore, how to efficiently and conveniently construct such compounds has aroused great interest. The palladium / copper-catalyzed Sonogashira coupling of ortho nucleophile-containing halides to terminal alkynes followed by intramolecular cyclization provides a facile and efficient synthetic route to this class of compounds. However, the disadvantage of this type of synthesis method is the use of palladium / copper bimetallic catalytic system. Due to the high price of palladium catalyst, it is difficult to separate...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D307/79C07D307/80C07D407/04C07D209/08C07D209/12
Inventor 周磊肖铁波王剑波
Owner SUN YAT SEN UNIV
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