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Chemical synthetic method for para-methyl catechol diacetoxyl dimethyl ester

A technology for the synthesis of methyl catechol diacetate dimethyl ester and its synthesis method, which is applied in the fields of chemical instruments and methods, organic chemistry, carboxylate preparation, etc., can solve the problems of difficult control of reaction conditions and easy side reactions, etc., and achieve The effect of low equipment requirements, low production costs, and mild reaction conditions

Inactive Publication Date: 2009-09-30
杭州浙大泛科化工有限公司
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  • Abstract
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Problems solved by technology

The synthesis of p-methylcatechol diacetate dimethyl ester also has bibliographical information, as magazine Journal of Porphyrins and Phthalocyanines (10 (12), 1360-1370; 2006) reported to synthesize p-methyl catechol diacetate reaction with bromoacetate Dimethyl catechol diacetate, but the reaction conditions are difficult to control, easy to produce side reactions, and the yield is only 55%

Method used

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  • Chemical synthetic method for para-methyl catechol diacetoxyl dimethyl ester

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Embodiment 1

[0016] 1) After mixing p-cresol, acetic anhydride and concentrated sulfuric acid at a molar ratio of 1:1:0.001, reflux reaction under stirring for 0.5h, after the reaction, distill off the generated acetic acid and excess acetic anhydride at 150°C to obtain phenol ester;

[0017] 2) At 60°C, add anhydrous aluminum trichloride to the phenolic ester, continue stirring for 0.5h, add 4mol / L hydrochloric acid at 50°C for hydrolysis reaction, and separate the upper layer of organic layer, the lower aqueous layer was extracted with benzene, all organic layers were kept and combined, and concentrated under reduced pressure to obtain phenolic ketone 2-hydroxyl-5-methylacetophenone, wherein the molar ratio of phenolic ester and aluminum chloride was 1:1 , The molar ratio of phenol ester to hydrochloric acid is 1:1~10.

[0018] 3) Dissolving 2-hydroxy-5-methylacetophenone in 3 times the mass of ethanol, slowly adding the pre-prepared aqueous alkaline hydrogen peroxide solution dropwise ...

Embodiment 2

[0021] 1) After mixing p-cresol, acetic anhydride and concentrated sulfuric acid in a molar ratio of 1:2:0.1, reflux reaction under stirring for 8 hours, after the reaction, distill off the generated acetic acid and excess acetic anhydride at 250°C to obtain phenolic ester ;

[0022] 2) At 200°C, add anhydrous aluminum trichloride to the phenolic ester, continue stirring for 5 hours, add 4mol / L hydrochloric acid at 150°C for hydrolysis reaction, after the solution is separated, separate the upper organic layer , the lower aqueous layer was extracted with xylene, all organic layers were kept and combined, and concentrated under reduced pressure to obtain phenolic ketone 2-hydroxy-5-methylacetophenone, wherein the molar ratio of phenolic ester and aluminum chloride was 1:5 , the molar ratio of phenol ester and hydrochloric acid is 1:10.

[0023] 3) Dissolve 2-hydroxy-5-methylacetophenone in 2-propanol with 20 times the mass, slowly add the pre-prepared aqueous alkaline hydrogen...

Embodiment 3

[0026] In a 500ml three-necked flask equipped with a stirrer, a thermometer, and a detachable reflux condensing device, add 70g of p-cresol, then add 70g of acetic anhydride and 5 drops of concentrated sulfuric acid, heat in an oil bath, and reflux for 2 hours under stirring, then change to reflux The device is an atmospheric distillation device, the temperature of the oil bath is slowly raised to 200°C, the temperature of the kettle is 170°C, and the acetic acid and excess acetic anhydride generated by the reaction are distilled off. The temperature of the reaction liquid was adjusted and maintained at 110° C., and 120 g of anhydrous aluminum trichloride was added. After the addition is complete, heat and stir the reaction for 1 hour, stop stirring, slowly add 300mL of 4mol / L hydrochloric acid, keep the temperature of the reaction solution at 115°C, keep the flask in a boiling state, and slowly hydrolyze the solid until it disappears. During this process, there is a small amou...

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Abstract

The invention relates to a synthetic method for para-methyl catechol diacetoxyl dimethyl ester. The method uses paracresol as an initial raw material to synthesize the para-methyl catechol diacetoxyl dimethyl ester into a target compound through acetylation reaction catalyzed by acid, Fries rearrangement reaction of phenolic ester, Dakin oxidation reaction of 2-hydroxy-5-methyl acetophenone and direct etherification reaction of para-methyl catechol. The total yield of the whole reaction is more than 70 percent, and the purity of the product is more than 98 percent. The method of the invention has the characteristics of easily-obtained raw materials, mild reaction condition, low equipment requirement, simple operation, low production cost, little side reaction, simple post treatment, and the like. Therefore, the synthetic method of the invention is a method suitable for industrialized production.

Description

technical field [0001] The invention relates to a method for synthesizing dimethyl catechol diacetate. The method uses p-cresol as a starting material to synthesize the target compound p-methylcatechol diacetate dimethyl through acetylation reaction, Fries rearrangement reaction, Dakin oxidation reaction and etherification reaction. Background technique [0002] Dimethyl-p-methylcatechol diacetate is an important drug intermediate of antibiotics, oxidation inhibitors, receptor stimulants and bronchodilators. In addition, dimethyl p-methylcatechol diacetate and its intermediate p-methylcatechol can also be used to prepare other pharmaceutical active compounds, antioxidants, photosensitizers, pesticides, spices, etc., and have a wide range of application fields. [0003] The preparation of intermediate p-methylcatechol has been reported in some patents, such as Chinese patent CN1298857, which uses titanium-silicon molecular sieves as a catalyst to carry out hydroxylation of p...

Claims

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Application Information

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IPC IPC(8): C07C69/736C07C67/31
Inventor 胡正良金桥沈阳华玉平
Owner 杭州浙大泛科化工有限公司
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