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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: 2013-07-03
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] Synthesis of 1.2-amino-3-nitro-6-chloropyridine

[0034] Put 500mL of isopropanol into the reaction pot, then add 50g of 2,6-dichloro-3-nitropyridine, stir until it is completely dissolved, stir at 25℃ and add ammonia gas, the solution will gradually become thicker and produce yellow Suspension, reaction for about 20h, TLC monitors that the reaction is complete and stops the reaction. 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 product with a yield of 98.5%. mp179~181℃.

[0035] Synthesis of 2.2-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 500 mL of isopropanol was added. Under stirring, 45mL of p-fluorobenzylamine and 75mL of triethylamine were added dropwise to the solution synthesized in the previous step...

Embodiment 2

[0044] Refined flupirtine maleate

[0045] Weigh 5.0g of flupirtine maleate, add 60ml of isopropanol, heat under reflux to dissolve, after flupirtine maleate is completely dissolved, cool, add 1.5g of activated carbon, continue heating under reflux, stop heating after 30 minutes, filter The activated carbon was removed to obtain a clear filtrate, which was crystallized in the refrigerator after being placed at room temperature. After 5 hours, it was filtered to obtain 3.5g of flupirtine maleate refined product, mp165-170℃.

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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 process for the synthesis of flupirtine maleate, and 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 for the preparation of analgesic drugs, and its chemical name is 2-amino-6-[(4-fluorobenzyl)amino]pyridine-3-carbamic acid ethyl ester maleate Acid salt, molecular formula: C 18 H 21 F 1 N 4 O 6 ; Molecular weight: 420.4. [0003] The synthetic routes of flupirtine maleate reported in the literature mainly include the following methods: [0004] 1. Von.Bebenburg uses p-fluorophenyl bromide as the starting material to synthesize p-fluorobenzylamine, which is then substituted with 2-amino-3-nitro-6-chloropyridine to form the intermediate 2-amino-3-nitro- 6-P-fluorobenzylaminopyridine, this intermediate is reduced by catalytic hydrogenation, selectively acylated with ethyl chloroformate to form flupir...

Claims

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Application Information

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Patent Type & Authority Patents(China)
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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