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Method for preparing trans-4-acetamido-cyclohexanol acetic ester

A technology of acetamido, alcohol acetate, applied in the preparation of carboxylic acid amide optical isomers, organic chemistry, etc., can solve problems such as adding reaction steps, and achieve the effects of simple raw materials, easy operation and high crystallization yield

Active Publication Date: 2012-04-25
浙江清和新材料科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

This patent separates the cis and trans isomers through selective reactions, but increases the reaction steps. It is necessary to hydrolyze the cis and trans mixed 4-acetylaminocyclohexanol to obtain the cis and trans mixed 4-aminocyclohexanol, and then select Sexual reaction to get trans-Schiff base, hydrolysis again to get trans-4-aminocyclohexanol

Method used

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  • Method for preparing trans-4-acetamido-cyclohexanol acetic ester

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] The molar ratio of the feed material is 4-acetylaminocyclohexanol:acetic anhydride=1.0:1.0. Wherein the 4-acetylaminocyclohexanol cis-trans ratio is 30:70.

[0029] Add acetic anhydride (102g, 1.0mol) in the reaction flask, add 4-acetylaminocyclohexanol (157g, 1.0mol) under stirring, the reaction system is exothermic, after the natural temperature rise of the reaction mixture system slows down, heat to reflux reaction 2 hours later. Cool to 85°C, and recover the generated acetic acid by distillation under reduced pressure. The remaining solid was added to 500mL ethyl acetate, heated to reflux until the solid was dissolved, cooled to about 10°C for recrystallization, and 79.8 g of filtered white solid trans-4-acetylaminocyclohexanol acetate, with a molar yield of 40.1% ( Based on the amount of the cis-trans mixture in the raw material, the molar yield=the amount of trans-4-acetamidocyclohexanol acetate / 4-acetamidocyclohexanol in the examples) -The yield of isomer cont...

Embodiment 2

[0031] The molar ratio of the feed material is 4-acetylaminocyclohexanol:acetic anhydride=1.0:1.1. Wherein the 4-acetylaminocyclohexanol cis-trans ratio is 30:70.

[0032] Add acetic anhydride (112g, 1.10mol) in the reaction flask, add 4-acetylaminocyclohexanol (157g, 1.0mol) under stirring, the reaction system exotherms, after the natural temperature rise of the reaction mixture system slows down, heat to reflux reaction 2 Hour. Cool to 85°C, and recover the generated acetic acid and excess acetic anhydride by distillation under reduced pressure. Add 500mL ethyl acetate to the remaining solid, heat and reflux until the solid dissolves, cool to about 5°C to crystallize, and filter the white solid trans-4-acetylaminocyclohexanol acetate 83.9g, the molar yield is 42.2% (based on raw material The yield in terms of trans-isomer content is 60.3%), the melting point is 158-161°C, and the liquid phase purity is 99.3%.

Embodiment 3

[0034] The molar ratio of the feed material is 4-acetylaminocyclohexanol:acetic anhydride=1.0:1.2. Wherein the 4-acetylaminocyclohexanol cis-trans ratio is 30:70.

[0035] Add acetic anhydride (122g, 1.2mol) in the reaction flask, add 4-acetylaminocyclohexanol (157g, 1.0mol) under stirring, the reaction system is exothermic, after the natural temperature rise of the reaction mixed system slows down, heat to reflux reaction 2 Hour. Cool to 85°C, and recover the generated acetic acid and excess acetic anhydride by distillation under reduced pressure. Add 500mL ethyl acetate to the remaining solid, heat to reflux until the solid dissolves, cool to 15°C to crystallize, and filter the white solid trans-4-acetamidocyclohexanol acetate 95.5g, molar yield 48% (from the raw material Trans-isomer content yield 68.6%), melting point 158-161 ° C, liquid phase purity 99.3%.

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Abstract

The invention relates to a method for preparing trans-4-acetamido-cyclohexanol acetic ester, which belongs to the technical field of chemical medicines. The method comprises the following steps: esterifying cis-trans mixed 4-acetamido-cyclohexanol by acetic anhydride and recrystallizing to obtain the trans-4-acetamido-cyclohexanol acetic ester. A 4- acetamido-cyclohexanol cis-trans isomer is separated by an esterification recrystallizing method; and after an esterified product is recrystallized, the trans-4-acetamido-cyclohexanol acetic ester is obtained. The invention has high one-step crystallization yield, trans-isomer purity more than 99 percent, simple and convenient operation, recyclable solvent and less environmental pollution and is suitable for industrialized production.

Description

technical field [0001] The invention belongs to the technical field of chemical industry and medicine, and specifically relates to a method for preparing trans-4-acetylaminocyclohexanol acetate through esterification and recrystallization of 4-acetylaminocyclohexanol. Background technique [0002] Trans-4-acetylaminocyclohexanol acetate can be hydrolyzed to obtain trans-4-aminocyclohexanol, which is an important pharmaceutical intermediate and can be used for expectorants Synthesis of Ambroxol and other drugs. [0003] The literature synthesis method of trans-4-aminocyclohexanol is mainly to obtain cis-trans mixed 4-acetamidocyclohexanol through hydrogenation of acetaminophen, then further separate the cis-trans isomers, and hydrolyze to obtain trans-4 -aminocyclohexanol. This shows that its key step is the separation of the cis and trans isomers of 4-acetylamino cyclohexanol. The current main methods are as follows: 1. The cis-trans mixed 4-acetylaminocyclohexanol is obt...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C233/23C07C231/20
Inventor 应素华王凌云吴利峰林介邦任松周泽泽张增礼
Owner 浙江清和新材料科技有限公司
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