Preparation method for 4-methoxy-1,3-phthalic acid

A technology of phthalic acid and methoxy, which is applied in the field of large-scale production of 4-methoxy-1,3-benzenedicarboxylic acid, can solve problems such as environmental hazards, equipment corrosion, and difficult completion, and reduce environmental pollution , less investment in equipment and low synthesis cost

Inactive Publication Date: 2017-11-10
TIANJIN UNIVERSITY OF TECHNOLOGY
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

This process encountered difficulties in the synthesis of enlarged doses, especially not suitable for large-scale industrial production
There are three main reasons for this. One is that in the Blanc chloromethylation process, large doses of concentrated sulfuric acid and concentrated hydrochloric acid will be used, which will inevitably bring harm to the environment and cause serious corrosion to the equipment, especially the large volume of hydrochloric acid left after the reaction. The problem of storage of waste sulfuric acid and waste hydrochloric acid is particularly serious; the second is that when th

Method used

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  • Preparation method for 4-methoxy-1,3-phthalic acid
  • Preparation method for 4-methoxy-1,3-phthalic acid
  • Preparation method for 4-methoxy-1,3-phthalic acid

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Embodiment 1

[0025] The present embodiment adopts p-cresol (1) as starting raw material, obtains p-methylphenyl acetate (2) through esterification reaction, obtains 5-methyl-2-hydroxyacetophenone (3) through Fries rearrangement reaction ), through methylation reaction to obtain 5-methyl-2-methoxyacetophenone (4), through oxidation reaction to obtain 4-methoxy-1,3-phthalic acid salt, through acidification reaction to obtain 4 -Methoxy-1,3-phthalic acid (6).

[0026] Reaction 1:

[0027]

[0028] Synthesis of 5-methyl-2-hydroxyacetophenone (3)

[0029] Put 20g of p-cresol in a 250mL round bottom flask, add 18mL of acetic anhydride and 30g of aluminum trichloride, and react at 110°C for 8h. Add 100 mL of hydrochloric acid. Extract with dichloromethane. 27.5 g of crude product 5-methyl-2-hydroxyacetophenone (3) was obtained, with a yield of 99.0%, which could be directly used in the next step without purification.

[0030] Reagents in this step include carboxylic acids, acid halides an...

Embodiment 2

[0038] Adopt o-cresol as starting material (7), obtain o-methyl phenyl acetate (8) through esterification, obtain 3-methyl-4-hydroxyacetophenone (9) through Fries rearrangement reaction, obtain through The methylation reaction gives 4-methoxy-3-methylacetophenone (10), the oxidation reaction gives 4-methoxy-1,3-benzenedicarboxylate (11), and the acidification reaction gives 4 -Oxymethyl-1,3-phthalic acid.

[0039] Reaction 2:

[0040]

[0041] Synthesis of 3-methyl-4-hydroxyacetophenone (9)

[0042] Put 20g of o-cresol in a 250mL round bottom flask, add 18mL of acetic anhydride and 30g of aluminum trichloride, and react at 160°C for 8h. Add 100 mL of hydrochloric acid. Extract with dichloromethane. 26.5 g of crude product 3-methyl-4-hydroxyacetophenone (9) was obtained, with a yield of 95.0%, which could be directly used in the next step without purification.

[0043] The reaction reagent used in this step includes carboxylic acid, carboxylic acid ester, acid chloride ...

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Abstract

The invention provides a preparation method for 4-methoxy-1,3-phthalic acid. 4-methoxy-1,3-phthalic acid is key intermediate for preparation of an anti-platelet aggregation drug picotamide (with a trade name of plactidil). According to the preparation method, 4-methoxy-1,3-phthalic acid is prepared from the starting raw material p-methylphenol or o-methylphenol through esterification, Fries rearrangement, methylation, oxidation and acidification. Compared with traditional preparation methods, the preparation method provided by the invention has the advantages of low equipment investment, simple operation, quick reaction, high yield, low synthesis cost, greatly reduced environmental pollution and the like, and is particularly suitable for large-scale industrial production.

Description

technical field [0001] The invention relates to a new method for preparing 4-methoxy-1,3-benzenedicarboxylic acid, which is especially suitable for large-scale production of 4-methoxy-1,3-benzenedicarboxylic acid, and has not been reported in literature so far. Background technique [0002] 4-Methoxy-1,3-benzenedicarboxylic acid is a key intermediate in the preparation of the anti-platelet aggregation drug Picotamide (Picotamide, trade name: Plactidil). At present, the relevant literature reports on the synthesis method of 4-methoxyl-1,3-benzenedicarboxylic acid, involving many different raw materials, such as 2,4-dimethylphenol, anisole and o-methyl anisole, etc. The most used method is anisole or 4-methyl anisole as a raw material, which is subjected to chloromethylation by Blanc (Frank) reaction to obtain 2,4-dichloromethyl anisole or 2-chloromethyl 4-Methylanisole is oxidized to obtain the intermediate 4-methoxy-1,3-benzenedicarboxylic acid (Route 1). When this method ...

Claims

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Application Information

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IPC IPC(8): C07C51/02C07C65/21
CPCC07C45/54C07C45/64C07C51/02C07C51/16C07C51/41C07C67/08C07C65/21C07C49/84C07C49/825C07C69/157
Inventor 刘秀杰王朝清李旭
Owner TIANJIN UNIVERSITY OF TECHNOLOGY
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