Preparation method of flupirtine maleate

A technology of flupirtine maleate and crude flupirtine acid, which is applied in the field of preparation of flupirtine maleate, can solve the problems of poor purification effect and low purity, achieve simple operation, high product purity, and avoid oxidation Effect

Active Publication Date: 2013-09-04
SUZHOU ERYE PHARMA CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The simplified method omits the reduction step and secondary salt-forming step in the first method, the operation is more convenient, the product loss is relatively small, and the yield can reach 75-85% of the original crude product weight, but its purification effect is poor , lower purity

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0039] Add flupirtine (2.88Kg, 10mol) into a reactor filled with 20L of isopropanol, start stirring and blow in nitrogen, control the speed at 2000-2500 rpm, and then cool down the reactor to 0°C. Dilute maleic acid (1.16Kg, 10mol) with 2L isopropanol, mix well and divide into 4 parts, 500 mL each. Slowly add the first isopropanol solution of maleic acid into the reaction kettle dropwise, and the dropping time is controlled at 50-70 minutes. After the dropping is completed, continue to stir for 1 hour, and then stand for crystallization for 1 hour, and a large amount of white solid. The solid and the reaction solution were separated by filtration, and the second part of maleic acid in isopropanol was added dropwise to the reaction solution, and the above operation was repeated until all 4 parts of maleic acid were added to the reaction solution. The filtered solids were combined and dried in vacuo to obtain 3.8 Kg of crude flupirtine maleate with a yield of 95%. As detected ...

Embodiment 2

[0043] Add flupirtine (2.88Kg, 10mol) into a reactor filled with 20L of isopropanol, start stirring and blow in nitrogen, control the speed at 2000-2500 rpm, and then cool down the reactor to 5°C. Dilute maleic acid (1.16Kg, 10mol) with 2L isopropanol, mix well and divide into 4 parts, 500 mL each. Slowly add the first isopropanol solution of maleic acid into the reaction kettle dropwise, and the dropping time is controlled at 50-70 minutes. After the dropping is completed, continue to stir for 2 hours, and then stand for 2 hours for crystallization, and a large amount of white solid. The solid and the reaction solution were separated by filtration, and the second part of maleic acid in isopropanol was added dropwise to the reaction solution, and the above operation was repeated until all 4 parts of maleic acid were added to the reaction solution. The filtered solids were combined and dried in vacuo to obtain 3.75 Kg of crude flupirtine maleate with a yield of 93.7%. Detecte...

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Abstract

The invention relates to a preparation method of flupirtine maleate, which takes flupirtine as a raw material, and obtains flupirtine maleate pure products through salification and fine purification steps. By strictly controlling the use level and the reaction condition of maleic acid, the method greatly improves the yield of crude products, adopts a fine purification method integrating ultrafiltration and recrystallization, avoids product loss caused by adopting activated carbon, and greatly improves the purity and the yield of the flupirtine maleate pure products.

Description

[0001] technical field [0002] The invention belongs to the field of medicinal chemistry, and in particular relates to a preparation method of flupirtine maleate. [0003] Background technique [0004] Flupirtine maleate, the chemical name is 2-amino-3-ethoxyamido-6-p-fluorobenzylaminopyridine maleate, the structural formula is as follows: [0005] . [0006] Flupirtine was synthesized by HomBurg in a pharmaceutical research institute in Frankfurt, Germany in 1981. It is marketed by Aster Medica under the trade name Katabolic and is a moderate-strength non-opioid central analgesic. Compared with painkillers that act on opioid receptors, flupirtine has the advantage of being less addictive, and this is the hot spot and difficulty in the current research and development of painkillers. [0007] At present, for the synthesis of flupirtine maleate, the widely used method is to acidify flupirtine (ie "2-amino-3-ethoxyamido-6-p-fluorobenzylaminopyridine") with maleic acid A...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D213/75C07C57/145C07C51/41C07C51/43
Inventor 时明生张健陈学文
Owner SUZHOU ERYE PHARMA CO LTD
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