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Method for preparing 2-amino-3-methyl-4-methoxy acetophenone

A technology of methoxyacetophenone and methyl, which is applied in the field of preparation of pharmaceutical intermediates, can solve the problems of high cost, complicated operation, and long time consumption in the post-processing process, and achieve high yield, simple operation, and low cost. Effect

Active Publication Date: 2011-03-23
KAIHUI SCI & TECH DEV SHANGHAI
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] The technical problem to be solved by the present invention is to overcome the low yield of the preparation method of 2-amino-3-methyl-4-methoxyacetophenone in the prior art, complicated operation, high cost and long time-consuming of post-treatment process , is not suitable for industrialized production, and provides a high yield, simple, feasible, and low-cost preparation method, which is suitable for industrialized production

Method used

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  • Method for preparing 2-amino-3-methyl-4-methoxy acetophenone

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Embodiment 1

[0036] Embodiment 1 prepares 2-amino-3-methyl-4-methoxyacetophenone (compound B)

[0037] Under nitrogen protection, compound A (6.85 g, 0.05 mol) was dissolved in dichloromethane (10 ml), cooled to below -10 degrees, and boron trichloride dichloromethane solution (1M, 55 mL, 0.055 mol) was added to react for 0.5 Hour. After cooling to below -50°C, acetyl chloride (3.45 g, 0.044 mol) and aluminum trichloride (6.4 g, 0.048 mol) were added in sequence. Connect the tail gas receiving device, stir and react at -50°C for 1 hour, naturally raise the temperature to room temperature and react for 12 hours, then raise the temperature and reflux for 4 hours. LCMS analysis confirmed the reaction was complete.

[0038] Cool to room temperature and quench with ice water. 20% (mass ratio) sodium hydroxide aqueous solution was used to adjust the pH of the aqueous layer to 6-7, extracted three times with dichloromethane, the organic phases were combined and dried, and the solvent was recov...

Embodiment 2

[0039] Embodiment 2 prepares 2-amino-3-methyl-4-methoxyacetophenone (compound B)

[0040] Compound A (13.7 g, 0.1 mol) was dissolved in dichloromethane (100 ml) under the protection of nitrogen, cooled to below -10°C, and boron trichloride gas (12.9 g, 0.11 mol) was introduced to react for 0.5 hours. After cooling to below -50°C, acetyl chloride (7.1 g, 0.09 mol) and aluminum trichloride (13.4 g, 0.1 mol) were added in sequence. Connect the tail gas receiving device, stir and react at -50°C for 1 hour, naturally raise the temperature to room temperature and react for 12 hours, then raise the temperature and reflux for 4 hours. LCMS analysis confirmed the reaction was complete.

[0041] Cool to room temperature and quench with ice water. 20% (mass ratio) sodium hydroxide aqueous solution was used to adjust the pH of the aqueous layer to 6-7, extracted three times with dichloromethane, the organic phases were combined and dried, and the solvent was recovered by distillation un...

Embodiment 3

[0042] Embodiment 3 prepares 2-amino-3-methyl-4-methoxyacetophenone (compound B)

[0043] Under nitrogen protection, compound A (13.7 grams, 0.1mol) was dissolved in dichloromethane (100ml), cooled to below -10 degrees, passed into boron trichloride dichloromethane solution (1M, 110mL, 0.11mol), and reacted 0.5 hours. After cooling to below -50°C, acetonitrile (4.1 g, 0.1 mol) and aluminum chloride (13.4 g, 0.1 mol) were added in sequence. Connect the tail gas receiving device, stir and react at -50°C for 1 hour, naturally raise the temperature to room temperature and react for 12 hours, then raise the temperature and reflux for 4 hours. LCMS analysis confirmed the reaction was complete.

[0044]Cool to room temperature and quench with ice water (150ml). The temperature was raised to reflux for another 6 hours, and LCMS analysis confirmed that the reaction was complete. Let cool to room temperature. 20% (mass ratio) sodium hydroxide aqueous solution was used to adjust the...

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Abstract

The invention provides a method for preparing 2-amino-3-methyl-4-methoxy acetophenone, which is characterized by comprising the following step of: under the protection of inert gas, performing Friedel-Crafts reaction on a compound A and an acetylation reagent in an organic solvent under the catalysis of boron trichloride and other Lewis acids to obtain a compound B, namely the 2-amino-3-methyl-4-methoxy acetophenone. The acetylation reagent is taken as a reactant, so the defects that operation is complex, yield is low and a post-treatment process has high cost and is time-consuming and unsuitable for industrial production in the prior art are overcome, and the preparation method which has high yield and mild reaction conditions, is simple and practicable and does not need a hydrolysis process is provided. In a preferable embodiment of the invention, recrystallization is performed for purification, the purification method does not need column chromatography or a large amount of alkali liquor for cleaning, and the method has high yield and low cost and is suitable for industrial production.

Description

technical field [0001] The invention relates to a preparation method of a pharmaceutical intermediate, in particular to a preparation method of 2-amino-3-methyl-4-methoxyacetophenone. Background technique [0002] 2-amino-3-methyl-4-methoxyacetophenone (compound B), has the following structural formula: [0003] [0004] The compound is a commonly used intermediate in the field of drug synthesis and has a wide range of applications. For example, it can be used as a synthetic intermediate for anti-hepatitis B, anti-AIDS, anti-tumor and other drugs. [0005] Compound B is generally obtained by hydrolyzing compound A and acetonitrile in xylene for a long time at high temperature, and it needs to be separated through a silica gel column or washed with a large amount of lye to obtain a pure compound (see WO2007014926; Aminohaloborane in organic synthesis.2.simple synthesis of indoles and 1-acyl-3-indolinones using specific ortho α-chloroacetylation of anilines, J.Org.Chem 19...

Claims

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Application Information

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IPC IPC(8): C07C225/22C07C221/00
Inventor 何成江王传旺李原强
Owner KAIHUI SCI & TECH DEV SHANGHAI
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