Preparation technique of 5-methoxy-2-tetralone

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

Active Publication Date: 2009-07-01
启东市滨化供水有限公司
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Problems solved by technology

[0020] 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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  • Preparation technique of 5-methoxy-2-tetralone
  • Preparation technique of 5-methoxy-2-tetralone
  • Preparation technique of 5-methoxy-2-tetralone

Examples

Experimental program
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Embodiment 1

[0031] In a 1000mL four-necked bottle, 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.

[0032] 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%.

[0033] As a result of gas chromatography analysis, 5-methoxy-2-tetralone was 46....

Embodiment 2

[0035] In a 1000mL four-necked bottle, 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.

[0036] 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%.

[0037] As a result of gas chromatography analysis, 5-methoxy-2-tetral...

Embodiment 3

[0039] In a 1000mL four-necked bottle, 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.

[0040] 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%.

[0041] As a result of gas chromatography analysis, 5-methoxy-2-tetralone was 44.9%...

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Abstract

The invention discloses technology for preparing 5-methoxyl-2-tetralone, which belongs to a method for preparing tetralone compounds and is technology for preparing the 5-methoxyl-2-tetralone by using sodium metals to reduce 1,6-dimethoxy benzene in an alcohol medium and an ammonia medium at a temperature of between 15 and 35 DEG C, wherein the weight ratio of anhydrous alcohol to the 1,6-dimethoxy benzene during reduction is 6.0-9.0:1; the weight ratio of an ammonia liquid to the 1,6-dimethoxy benzene is 0.05-0.4:1; the weight ratio of the sodium metals to the 1,6-dimethoxy benzene is 0.7-1.2:1; and the reduction temperature is between 15 and 35 DEG C, and the reduction time is between 35 and 48 hours. The technology for preparing the 5-methoxyl-2-tetralone has the advantages of easily obtained reaction raw materials, simple conditions, easy industrialization and high selectivity of the 5-methoxyl-2-tetralone. The 5-methoxyl-2-tetralone is important medical intermediate, and is mainly used for synthesizing medicines for treating Parkinson's disease.

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 one, prepare by diazoketone (Alex A C, etc. Journal of Chemistry Society, PerkinTransaction.1, 1993, (1): 3-4), raw material diazoketone source has difficulty, is catalyst with rhodium acetate, and price is relatively high expensive. [0004] [0005] Method 2: Prepared from o-hydroxybenzaldehyde (Somnath G, etc. Tetrahedron, 1989, 45 (5): 1441- [0006] [0007] 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 difficult. Na—Hg a...

Claims

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Application Information

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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
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