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Preparation method of methyl 4-methylcinnamate

A technology of methyl cinnamate and p-methylbenzaldehyde, which is applied in the preparation of carboxylate, the preparation of organic compounds, chemical instruments and methods, etc., can solve the problem of not meeting green production requirements, long reaction time, poor production conditions, etc. problems, to achieve the effects of stable and reliable product quality, simple method and increased yield

Inactive Publication Date: 2012-08-08
湖北远成赛创科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] 1. Prepare with absolute ethanol as solvent and 10% NaOH as catalyst, but this method has long reaction time, many side reactions, low product yield and poor production efficiency
[0005] 2. It is formed by condensation with acetate as solvent and sodium alkoxide as catalyst. This method improves the product yield, but the post-treatment is complicated and the purification is difficult.
Because the existing process has many steps, poor production conditions, low product yield, high cost and serious pollution, it does not meet the requirements of green production

Method used

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  • Preparation method of methyl 4-methylcinnamate

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] In the three-necked flask, add 9.0g (0.1mol) DME, 5.6g (0.0525mol) LDA and 3.7g (0.05mol) methyl acetate, after stirring for 0.5h under ice-water bath, slowly add 6.3 g (0.0525mol) p-tolualdehyde, keep the temperature below 5°C; after dropping, keep it at 10°C for 3 hours, slowly add 10% sulfuric acid by mass percentage, and adjust the pH of the reaction solution between 6.8 and 7.2 Separate the organic layer, reclaim DME and excessive p-tolualdehyde under reduced pressure to obtain a white solid, then wash and dry to obtain the crude product, recrystallize with absolute ethanol to obtain 6.6g of methyl p-methyl cinnamate, the purity It was 98.7%, and the yield was 73.9% (calculated as methyl acetate).

Embodiment 2

[0026] In the three-necked flask, add 27.0g (0.3mol) DME, 11.8g (0.11mol) LDA and 7.4g (0.1mol) methyl acetate, after stirring for 0.5h under ice-water bath, slowly add 13.2 g (0.11mol) p-tolualdehyde, keep the temperature below 5°C; after dropping, keep it at 7°C for 4 hours, slowly add 10% sulfuric acid by mass percentage, and adjust the pH of the reaction solution between 6.8 and 7.2 Separate the organic layer, reclaim DME and excessive p-tolualdehyde under reduced pressure to obtain a white solid, then wash and dry to obtain the crude product, recrystallize with absolute ethanol to obtain 13.8g of methyl p-methyl cinnamate, the purity It was 99.1%, and the yield was 77.6% (calculated as methyl acetate).

Embodiment 3

[0028] In the three-necked flask, add 47.3g (0.525mol) DME, 19.3g (0.18mol) LDA and 11.1g (0.15mol) methyl acetate, after stirring for 0.5h under ice-water bath, slowly add 21.6 g (0.18mol) p-tolualdehyde, keep the temperature below 5°C; after dropping, keep it at 4°C for 5 hours, slowly add 10% sulfuric acid by mass percentage, and adjust the pH of the reaction solution between 6.8 and 7.2 Separate the organic layer, reclaim DME and excessive p-tolualdehyde under reduced pressure to obtain a white solid, then wash and dry to obtain the crude product, recrystallize with absolute ethanol to obtain 21.9g of methyl p-methyl cinnamate, the purity It was 99.5%, and the yield was 82.4% (calculated as methyl acetate).

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Abstract

The invention provides a preparation method of methyl 4-methylcinnamate. The preparation method comprises the following steps: stir-mixing glycol dimethyl ether which is used as a solvent, lithium diisopropylamide which is used as a catalyst, and methyl acetate, and slowly adding p-tolualdehyde in a dropwise manner under stirring at below 5DEG C; reacting for 3-6h at 0-10DEG C after ending the dropwise addition, and slowly adding sulfuric acid with the mass percent of 10% in a dropwise manner to regulate the pH of a reaction solution between 6.8-7.2; and separating the resulting organic layer, carrying out reduced pressure distillation to recover the solvent and excess p-tolualdehyde and obtain a white solid, washing the white solid with water, drying to obtain crude methyl 4-methylcinnamate, and recrystallizing the crude methyl 4-methylcinnamate to obtain methyl 4-methylcinnamate. The preparation method which has the advantages of low costs of raw materials, mild reaction condition, preparation of methyl 4-methylcinnamate through a one-step reaction, simplicity, easy operation, high yield, stable and reliable product quality, and no pollution to environment is a green synthetic method.

Description

technical field [0001] The invention relates to a method for preparing an organic synthesis intermediate, in particular to a method for preparing methyl p-methyl cinnamate. Background technique [0002] Methyl p-methyl cinnamate, also known as methyl 4-methyl cinnamate, as a pharmaceutical intermediate, is mainly used in the fields of medicine and chemical industry. For example, methyl p-bromomethyl cinnamate, the upstream raw material of the antithrombotic drug ozagrel, can be prepared through bromination reaction. [0003] The preparation of cinnamate by condensation of benzaldehyde with acetate is called Claisen-Schmidt condensation. The method for preparing cinnamate with Claisen-Schmidt reaction mainly contains: [0004] 1, with absolute ethanol as solvent, 10% NaOH is prepared as catalyst, but the reaction time of this method is long, and side reaction is many, and product yield is low, and production efficiency is poor. [0005] 2. It is formed by condensation with...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C69/618C07C67/343
Inventor 叶思朱如慧杨洁韩洪杰徐海林
Owner 湖北远成赛创科技有限公司
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