Process for preparing (+/-)-3-(Carbamoymethyl)-5-methylhexanoic acid

A technology of methylhexanoic acid and carbamoyl group is applied in the field of preparation of -3--5-methylhexanoic acid and achieves the effects of low cost, simple operation and high total yield

Active Publication Date: 2013-03-13
太仓市茜泾化工有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

There is no Chinese patent report about the prepa...

Method used

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Examples

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Effect test

Embodiment 1

[0014] Example 1 Preparation of 3-isobutylglutaric acid

[0015] Add 18.5g (0.22mol) of cyanoacetamide, 50g of water, and 0.5g of catalyst (DMF) into a four-neck flask equipped with a reflux condenser, a thermometer, a stirrer and a constant pressure dropping funnel, and cool to 5~15°C , Stir and add 8.6g (0.1mol) of isovaleraldehyde, react at 5~15°C for 8 hours, keep warm, cool, add 70g (0.7mol) of 98% sulfuric acid dropwise, control the internal temperature at 30~50°C, dropwise time 2~3 hours, add dropwise, keep warm at 30~50°C for 3 hours, then slowly raise the temperature to 70~80°C, keep warm for 1 hour, then raise the temperature to reflux, the temperature is 100~110°C, reflux reaction for 3 hours , then distill the water at normal pressure to an internal temperature of 130~135°C, stop distilling water, and reflux at this temperature for 3 hours. After the reaction, cool to 50~60°C, add 50ml of toluene, and stir at 50~60°C After 0.5~1 hour, it is static and stratifi...

Embodiment 2

[0016] Example 2 Preparation of 3-isobutylvaleric anhydride

[0017] In a four-necked flask equipped with a reflux condenser, a thermometer, and a stirrer, add 37.6 g (0.2 mol) of 3-isobutylglutaric acid glutaric acid and 30.6 g (0.3 mol) of acetic anhydride, raise the temperature to reflux, and keep reflux React for 3 hours. Then distill a part of acetic acid and acetic anhydride, stop the distillation after the internal temperature reaches 100~120°C, and keep the reaction at 120°C for 4 hours. After the reaction is completed, cool down to lower the temperature to below 80°C, turn on the vacuum, start vacuum distillation to remove the low boiling point, and start vacuum distillation to obtain 32 g of 3-isobutylvaleric anhydride, the HPLC content is 98.5%, and the yield is ≥90%.

Embodiment 3

[0018] The preparation of embodiment 3 (±)-3-(carbamoyl)-5-methylhexanoic acid

[0019] In a four-necked flask equipped with a thermometer and a stirrer, add 25 ml of methyl tert-butyl ether and 50 ml of water, and stir under 5° C., dropwise add 17 g of 3-isobutylvaleric anhydride prepared according to the method of Example 2 ( 0.1mol) and 22g (0.25mol) of ammonia water, the temperature is less than 0°C, after dripping, the pH=9, then control -5~0°C, keep warm for 4 hours, the pH remains unchanged, stand still for 0.5 hours, separate into layers, water layer Add 50ml of water, add 30wt% hydrochloric acid dropwise, control the temperature to less than 10°C, pH=1~2, discharge, filter to obtain 28g of crude wet product. The rough wet product is refined, and the method is as follows: After heating and dissolving 28g of the thick wet product with 280g methyl tert-butyl ether, divide the water, add 3g of activated carbon for decolorization, filter, cool and crystallize, filter, ...

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PUM

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Abstract

The invention relates to a process for preparing (+/-)-3-(Carbamoymethyl)-5-methylhexanoic acid. The process comprises the steps: (1) preparing 3-isobutylglutaric acid, namely, reacting cyanoacetamide with isovaleric aldehyde in the presence of a catalyst, and then adding concentrated sulfuric acid for reaction to obtain 3-isobutylglutaric acid; (2) reacting 3-isobutylglutaric acid with acetic anhydride to obtain 3-isobutylglutaric anhydride; and (3) reacting 3-isobutylglutaric anhydride with ammonia to produce (+/-)-3-(Carbamoymethyl)-5-methylhexanoic acid. According to the process, the raw materials adopted by the process are available, the operation is simple, the yield of each reaction is higher than 80 percent, the total yield of the target product is high, and the cost is low.

Description

technical field [0001] The invention relates to a preparation method of (±)-3-(carbamoyl)-5-methylhexanoic acid. Background technique [0002] Carbamoyl)-5-methylhexanoic acid is an important intermediate of Pregabalin. In the prior art, one method for preparing R-3-(carbamoyl)-5-methylhexanoic acid is chemical resolution of (±)-3-(carbamoyl)-5-methylhexanoic acid. So far, there is no Chinese patent report on the preparation method of (±)-3-(carbamoyl)-5-methylhexanoic acid. Contents of the invention [0003] The technical problem to be solved by the present invention is to overcome the deficiencies in the prior art, to provide a high yield, low cost, suitable for the preparation of (±)-3-(carbamoyl)-5-methylhexanoic acid for industrialized production method. [0004] In order to solve the above technical problems, the present invention takes the following technical solutions: [0005] A preparation method of (±)-3-(carbamoyl)-5-methylhexanoic acid, comprising the step...

Claims

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Application Information

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IPC IPC(8): C07C233/05C07C231/14
Inventor 秦正浩
Owner 太仓市茜泾化工有限公司
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