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A kind of preparation technology of 5-methoxy-2-tetralone

A preparation process and technology of dimethoxynaphthalene are applied in the field of preparation of tetralone compounds, and can solve the problems of low selectivity of 5-methoxy-2-tetralone, difficulty in purification and the like

Active Publication Date: 2011-12-07
启东市滨化供水有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0018] In order to overcome the problem that 1,6-dimethoxynaphthalene is reduced at high temperature in the existing synthesis method, the selectivity of 5-methoxy-2-tetralone is low and the purification is difficult, the present invention proposes a 1,6-dimethoxynaphthalene is reduced in ethanol and ammonia medium with metal sodium at 15-35°C to prepare 5-methoxy-2-tetralone

Method used

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  • A kind of preparation technology of 5-methoxy-2-tetralone
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  • A kind of preparation technology of 5-methoxy-2-tetralone

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Embodiment 1

[0029] In a 1000mL four-neck flask, add 1,6-dimethoxynaphthalene (1,6-OCH 3 ) 42g, absolute ethanol 289g, liquid ammonia 8.4g, stir until fully dissolved. Press 35g of sodium into filaments and add to the reaction solution in batches, adding 5g of Na each time, after 5g of Na disappears, continue to add 5g of Na. Control the rate of adding Na and the rate of heating so that the reduction temperature is at 25-35°C. From the beginning of sodium addition to the end of reduction, it takes about 48 hours.

[0030] Water was added dropwise to the reducing solution for dilution, and the mixture of ethanol and water was distilled off. Add water to the residual liquid of the kettle, stir and dilute, and separate the oil layer. The oil layer was mixed with dilute hydrochloric acid, stirred, refluxed for hydrolysis, and the oil layer was separated to obtain 5-methoxy-2-tetralone with a yield of 81%.

[0031] As a result of gas chromatography analysis, 5-methoxy-2-tetralone was 46.2%;...

Embodiment 2

[0033] In a 1000mL four-neck flask, add 1,6-dimethoxynaphthalene (1,6-OCH 3 ) 42g, absolute ethanol 340g, liquid ammonia 14.5g, stir until fully dissolved. Press 35g of sodium into filaments and add to the reaction solution in batches, adding 5g of Na each time, after 5g of Na disappears, continue to add 5g of Na. Control the rate of adding Na and the rate of heating so that the reduction temperature is between 15°C and 25°C. It takes about 40 hours from the beginning of sodium addition to the end of reduction.

[0034] Water was added dropwise to the reducing solution for dilution, and the mixture of ethanol and water was distilled off. Add water to the residual liquid of the kettle, stir and dilute, and separate the oil layer. The oil layer was mixed with dilute hydrochloric acid, stirred, refluxed and hydrolyzed, and the oil layer was separated to obtain 5-methoxy-2-tetralone with a yield of 82%.

[0035] As a result of gas chromatography analysis, 5-methoxy-2-tetralone...

Embodiment 3

[0037] In a 1000mL four-neck flask, add 1,6-dimethoxynaphthalene (1,6-OCH 3 ) 42g, absolute ethanol 370g, liquid ammonia 2.5g, stir until fully dissolved. Press 42g of sodium into filaments and add to the reaction liquid in batches, adding 5g of Na each time, after 5g of Na disappears, continue to add 5g of Na. Control the rate of adding Na and the rate of heating so that the reduction temperature is at 25-35°C. From the beginning of sodium addition to the end of reduction, it takes about 38 hours.

[0038] Water was added dropwise to the reducing solution for dilution, and the mixture of ethanol and water was distilled off. Add water to the residual liquid of the kettle, stir and dilute, and separate the oil layer. The oil layer was mixed with dilute hydrochloric acid, stirred, refluxed for hydrolysis, and the oil layer was separated to obtain 5-methoxy-2-tetralone with a yield of 79%.

[0039] As a result of gas chromatography analysis, 5-methoxy-2-tetralone was 44.9%; 2...

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Abstract

The invention discloses a preparation process of 5-methoxy-2-tetralone, which belongs to the preparation method of tetralone compounds. A process for preparing 5-methoxy-2-tetralone by reducing 1,6-dimethoxynaphthalene in ethanol and ammonia medium with metal sodium at 15-35°C. During the reduction process, the weight ratio of absolute ethanol to 1,6-dimethoxynaphthalene is 6.0-9.0:1; the weight ratio of liquid ammonia to 1,6-dimethoxynaphthalene is 0.05-0.4:1; The weight ratio of sodium to 1,6-dimethoxynaphthalene is 0.7-1.2:1; the reduction temperature is 15-35° C.; the reduction time is 35-48 hours. The reaction raw materials are easy to obtain, the conditions are not too complicated, the industrialization is easy, and the 5-methoxy-2-tetralone has the advantages of high selectivity. 5-methoxy-2-tetralone is a very important pharmaceutical intermediate, mainly used in the synthesis of drugs for the treatment of Parkinson's syndrome.

Description

Technical field: [0001] The invention belongs to the preparation method of tetralone compounds. Background technique: [0002] 5-methoxy-2-tetralone is a very important pharmaceutical intermediate, mainly used in the synthesis of drugs for the treatment of Parkinson's syndrome. The market demand is increasing year by year. The reported synthetic methods are: [0003] Method 1, preparation by diazoketone (Alex A C, etc. Journal of Chemistry Society, PerkinTransaction.1, 1993, (1): 3-4), the source of raw material diazoketone is difficult, and rhodium acetate is used as a catalyst, and the price is relatively high expensive. [0004] [0005] Method 2: Preparation from o-hydroxybenzaldehyde (Somnath G, et al. Tetrahedron, 1989, 45(5): 1441-1446) [0006] The total yield of this method is only 7.5%, which is too low. The whole synthesis process uses a variety of chemical reagents, and there are many steps, and the separation of intermediate products is also relatively ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C49/755C07C45/00
Inventor 袁仲飞张天永
Owner 启东市滨化供水有限公司