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Green synthesis of carbidopa midbody

A synthetic method, carbidopa technology, applied in chemical instruments and methods, preparation of organic compounds, preparation of urea derivatives, etc., can solve the problems of high industrial production cost, troublesome handling, environmental pollution, etc., and achieve low production cost , raw materials are cheap, and the raw materials are easy to obtain

Inactive Publication Date: 2008-05-07
ZHEJIANG UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The main disadvantage of this method is that it needs to consume a large amount of potassium cyanate and hydrochloric acid, and produce a large amount of waste water containing cyanide ions, causing environmental pollution, troublesome post-reaction treatment, and high industrial production costs

Method used

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  • Green synthesis of carbidopa midbody
  • Green synthesis of carbidopa midbody
  • Green synthesis of carbidopa midbody

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] The molar ratio of the feed material is (S)-2-(3,4-dimethoxybenzyl)-2-aminopropionic acid hydrochloride: urea: alkali=1: 1.5: 1.5, and the alkali is barium hydroxide, The solvent is water, and its dosage is 4 times the mass of (S)-2-(3,4-dimethoxybenzyl)-2-aminopropionic acid hydrochloride.

[0021] In a 500mL three-neck flask equipped with a thermometer, reflux condenser and mechanical stirring, add (S)-2-(3,4-dimethoxybenzyl)-2-aminopropionic acid hydrochloride (27.5g, 0.1 mol), urea (9.0g, 0.15mol), alkali (25.7g, 0.15mol), water (110g), start stirring and heating, control the temperature at 100°C, and stir for 3 hours. After cooling, it was acidified with 25% hydrochloric acid until the pH value was 2.5, a large amount of solids were precipitated, continued to stir for 30 minutes, filtered, and the solids were recrystallized with 80% ethanol to obtain a white solid, 14.1g, yield 50%, melting point: 205.0-205.4°C, HPLC purity 99.0%.

Embodiment 2

[0023] The molar ratio of the feed material is (S)-2-(3,4-dimethoxybenzyl)-2-aminopropionic acid hydrochloride: urea: alkali=1: 3.0: 2.0, and the alkali is barium hydroxide, The solvent is water, and its dosage is 6 times the mass of (S)-2-(3,4-dimethoxybenzyl)-2-aminopropionic acid hydrochloride.

[0024] In a 500mL three-neck flask equipped with a thermometer, reflux condenser and mechanical stirring, add (S)-2-(3,4-dimethoxybenzyl)-2-aminopropionic acid hydrochloride (27.5g, 0.1 mol), urea (18.0g, 0.3mol), alkali (34.2g, 0.2mol), water (110g), start stirring and heating, control the temperature at 100°C, and stir for 5 hours. After cooling, it was acidified with 20% hydrochloric acid until the pH value was 3, a large amount of solids were precipitated, continued to stir for 30 minutes, filtered, and the solids were recrystallized with 95% ethanol to obtain a white solid, 15.8g, yield 56%, melting point: 205.2-205.5°C, HPLC purity 99.1%.

Embodiment 3

[0026] The molar ratio of the feed material is (S)-2-(3,4-dimethoxybenzyl)-2-aminopropionic acid hydrochloride: urea: alkali=1: 6.0: 2.5, and the alkali is barium hydroxide, The solvent is water, and the amount used is 10 times the mass of (S)-2-(3,4-dimethoxybenzyl)-2-aminopropionic acid hydrochloride.

[0027] In a 500mL three-neck flask equipped with a thermometer, reflux condenser and mechanical stirring, add (S)-2-(3,4-dimethoxybenzyl)-2-aminopropionic acid hydrochloride (27.5g , 0.1mol), urea (36.0g, 0.6mol), alkali (42.75g, 0.25mol), water (275g), start stirring and heating, control the temperature at 100°C, and react for 4 hours. After cooling, it was acidified with 31% hydrochloric acid until the pH value was 2, a large amount of solids were precipitated, continued stirring for 30 minutes, filtered, and the solids were recrystallized with 50% ethanol to obtain a white solid, 18.33g, yield 65%, melting point: 205.0-205.4°C, HPLC purity 99.0%.

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Abstract

The present invention provides a green synthesis method of carbidopa intermediate, that is, an industrially advantageous method for preparing carbidopa intermediate L-2-(3,4-di The method of methoxybenzyl)-2-ureidopropionic acid, the described method is (S)-2-(3,4-dimethoxybenzyl)-2-aminopropionic acid hydrochloride and Urea is mixed and reacted in alkaline medium, and a large amount of white solid is precipitated after acidification, and recrystallized to obtain (S)-2-(3,4-dimethoxybenzyl)-2-ureidopropionic acid. Compared with the prior art, the present invention avoids the use of excess potassium cyanate, fundamentally eliminates the problems of troublesome post-reaction treatment and serious pollution of three wastes in the traditional process, and thus has the advantages of simple and safe operation, high reaction yield and low production cost , basically no three wastes, and has great implementation value and social and economic benefits.

Description

(1) Technical field [0001] The invention relates to a green synthesis method of carbidopa intermediate L-2-(3,4-dimethoxybenzyl)-2-ureidopropionic acid. (2) Background technology [0002] Carbidopa (I) is a decarboxylase inhibitor used to treat Parkinson's disease. It mainly inhibits the decarboxylation of peripheral levodopa into dopamine, so that more levodopa enters the brain and increases brain dopamine. It is one of the most important adjuvants of levodopa to reduce the adverse reactions caused by peripheral dopamine. One of the main routes for industrially preparing carbidopa is to use L-2-(3,4-dimethoxybenzyl)-2-ureidopropionic acid (II) as raw material, and carry out Hoffmann reaction with sodium hypochlorite to produce Obtain the corresponding L-2-(3,4-dimethoxybenzyl)-2-hydrazinopropionic acid, and obtain carbidopa (PL163152 and ES2026759) through deprotection reaction, therefore, L-2-( 3,4-dimethoxybenzyl)-2-ureidopropionic acid (II) is a key intermediate for th...

Claims

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Application Information

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IPC IPC(8): C07C275/24C07C273/18
Inventor 钟为慧江灵波陈霄苏为科
Owner ZHEJIANG UNIV OF TECH
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