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Synthesizing method of norfloxacin, ciprofloxacin and enrofloxacin

A technology of ciprofloxacin and norfloxacin, which is applied in the direction of organic chemistry, can solve the problems of low selectivity of the main reaction and high proportion of by-products substituted by six-position fluorine, and achieve low production cost, shortened reaction time, and high yield high effect

Inactive Publication Date: 2019-06-28
江西大地制药有限责任公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Among them, comparative examples 1 to 3 of the instructions use the condensation reaction of piperazine and quinoline carboxylic acid in a solvent under the catalysis of Lewis acid, with an average yield of 77.6%, a high proportion of by-products substituted by six-position fluorine, and low selectivity of the main reaction.

Method used

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  • Synthesizing method of norfloxacin, ciprofloxacin and enrofloxacin
  • Synthesizing method of norfloxacin, ciprofloxacin and enrofloxacin
  • Synthesizing method of norfloxacin, ciprofloxacin and enrofloxacin

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] Put 100g of 1-ethyl-6-fluoro-7-chloro-4-oxo-1,4-dihydro-quinoline-3-carboxylic acid into a four-neck flask, piperazine 160g, water 20g, aluminum tribromide 2g, heat up to 40°C, keep warm for 9h, add 30g of sodium hydroxide, depressurize to dryness to recover piperazine, then add 400g of water to the residue to dissolve, add 0.2g of activated carbon, decolorize at 70°C for 30 minutes, filter, add the filtrate Adjust the pH to neutral with hydrochloric acid, cool to room temperature and filter to obtain the crude product of norfloxacin, then recrystallize with ethanol, filter and dry to obtain the finished product of norfloxacin 108g, the molar yield liquid phase monitoring purity 99.72%, 6 fluorine substitution impurity 0.16 %, molar yield 91.0%.

Embodiment 2

[0019] Put 100g of 1-ethyl-6-fluoro-7-chloro-4-oxo-1,4-dihydro-quinoline-3-carboxylic acid into a four-neck flask, piperazine 125g, water 30g, aluminum tribromide 1.5g, heat up to 65°C, keep warm for 5h, add 30g of sodium hydroxide, decompress to dryness to recover piperazine, then add 400g of water to the residue to dissolve, add 0.2g of activated carbon, decolorize at 70°C for 30 minutes, filter, and the filtrate Add hydrochloric acid to adjust the pH to neutral, cool to room temperature and filter to obtain the crude product of norfloxacin, then recrystallize with ethanol, filter and dry to obtain the finished product of norfloxacin 107g, the molar yield liquid phase monitoring purity 99.76%, 6 fluorine substitution impurities 0.13%, molar yield 90.3%.

Embodiment 3

[0021] Put 100g of 1-ethyl-6fluoro-7-chloro-4-oxo-1,4-dihydro-quinoline-3-carboxylic acid, 150g of piperazine, 40g of water, and 3g of zinc bromide into a four-neck flask , heat up to 90°C, keep warm for 3 hours, add 30g of sodium hydroxide, decompress to dryness to recover piperazine, then add 400g of water to the residue to dissolve, add 0.2g of activated carbon, decolorize at 70°C for 30 minutes, filter, add hydrochloric acid to the filtrate Adjust the pH to neutral, cool to room temperature and filter to obtain the crude product of norfloxacin, then recrystallize with ethanol, filter and dry to obtain the finished product of norfloxacin 105g, the molar yield liquid phase monitoring purity 99.0%, 6 fluorine substitution impurity 0.5% , The molar yield is 87.7%.

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Abstract

The invention provides a preparing method of norfloxacin, ciprofloxacin and enrofloxacin. The preparing method comprises the step of reacting carboxylic acid with diethylenediamine in a solvent underthe catalytic action of a catalyst, wherein the catalyst is AlBr3, FeBr3, ZnBr2, CuBr2 or SnBr4. The preparing method has the advantages of being high in yield and low in cost, saving energy and reducing emission.

Description

technical field [0001] The invention belongs to the field of compound synthesis, and specifically relates to a synthesis method of norfloxacin, ciprofloxacin and enrofloxacin. Background technique [0002] Fluoronoquinones are structurally modified derivatives of 4-quinolones. After adding a fluorine (F) to the 6-position, it increases the fat solubility and enhances the penetration of tissue cells, so the absorption is good and the tissue concentration is high. , long half-life, greatly increased the antibacterial spectrum and bactericidal effect, so the synthesis of fluoroquinolones has become a very active research field. Among the fluoronoquinones, norfloxacin, ciprofloxacin and enrofloxacin have similar structures and close physical and chemical properties, so their synthesis is often studied as a whole. The core process of the synthesis of fluoronoquinones is the condensation reaction of piperazine and quinoline carboxylic acid, the patent CN201410532023.7, the invent...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D215/56
Inventor 陈大弟
Owner 江西大地制药有限责任公司
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