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Synthesis process of flupirtine maleate

A technology of flupirtine maleate and synthesis process, which is applied in the field of preparation of chemical raw materials, and can solve the problems of restricting the popularization and use of flupirtine maleate drug, complex synthetic route operation, and affecting production scale, etc., to meet the reaction conditions Ease of control, high yield, and ease of purchase

Active Publication Date: 2011-11-16
北京华睿鼎信科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0009] Based on the above synthetic techniques, the synthetic route of Von.Bebenburg etc. is complicated to operate and the yield is very low, which affects its production scale, thus restricting the popularization and use of flupirtine maleate medicine

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] 1. Synthesis of 2-amino-3-nitro-6-chloropyridine

[0034] Pour 500mL of isopropanol into the reaction pot, then add 50g of 2,6-dichloro-3-nitropyridine, stir until completely dissolved, then stir at 25°C and inject ammonia gas, the solution gradually becomes thicker and turns yellow The suspension was reacted for about 20 hours, and the reaction was stopped when the reaction was completely monitored by TLC. Filter to obtain yellow crystals. The filtrate was subjected to rotary evaporation to obtain another part of yellow crystals. Two parts of yellow crystals were washed with 100 mL of water and dried to obtain 44.3 g of the product with a yield of 98.5%. mp179~181℃.

[0035] 2. Synthesis of 2-amino-3-nitro-6-[(4-fluorobenzyl)amino]pyridine

[0036] 45g of 2-amino-3-nitro-6-chloropyridine was added to the reaction kettle, and then 500mL of isopropanol was added. While stirring, add 45 mL of p-fluorobenzylamine and 75 mL of triethylamine dropwise to the solution syn...

Embodiment 2

[0044] Refined flupirtine maleate

[0045]Weigh 5.0 g of flupirtine maleate, add 60 ml of isopropanol, heat and reflux to dissolve, after the flupirtine maleate is completely dissolved, cool, add 1.5 g of activated carbon, continue to heat and reflux, stop heating after 30 minutes, filter Remove the activated carbon to obtain a clear filtrate, which crystallized in the refrigerator after standing at room temperature. After 5 hours, it was filtered to obtain 3.5 g of refined flupirtine maleate, mp 165-170°C.

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PUM

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Abstract

The invention relates to a preparation method of flupirtine maleate. The method comprises the following steps of: 1, synthesizing 2-amino-3-nitro-6-chloropyridine; 2, synthesizing 2-amino-3-nitro-6-[(4-luorobenzyl)amino] pyridine; 3, synthesizing 2,3-diamino-6-[(4-luorobenzyl)amino] pyridine; 4, synthesizing 2-amino-3-nitro-ethyl carbamate-6-[(4-luorobenzyl)amino] pyridine; 5, synthesizing 2-amino-6-[(4-luorobenzyl)amino] pyridine-3-ethyl carbamate maleate; and 6, refining flupirtine maleate.

Description

technical field [0001] The invention relates to a new synthesis process of flupirtine maleate, which belongs to the technical field of preparation of chemical raw materials. Background technique [0002] The flupirtine maleate involved in the present invention is the main component of preparing analgesic drugs, and its chemical name is 2-amino-6-[(4-fluorobenzyl)amino]pyridine-3-carbamate ethyl ester maleate salt, molecular formula: C 18 h 21 f 1 N 4 o 6 ;Molecular weight: 420.4. [0003] The synthetic route of the flupirtine maleate reported in the literature mainly contains the following methods: [0004] 1. Von. Bebenburg synthesized p-fluorobenzylamine with p-fluorophenyl bromide as the starting material, and then substituted with 2-amino-3-nitro-6-chloropyridine to generate the intermediate 2-amino-3-nitro- 6-Fluorobenzylaminopyridine, the intermediate is reduced by catalytic hydrogenation, and selectively acylated with ethyl chloroformate to generate flupirtine ...

Claims

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Application Information

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IPC IPC(8): C07D213/75
Inventor 安明孙新超张楠
Owner 北京华睿鼎信科技有限公司
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