One pot synthetic method of 2,4-dichloro-3-nitro-5-fluoro-benzoic acid

A technology of fluorobenzoic acid and synthetic method, applied in two fields, can solve the problems of cumbersome operation, many steps, difficult starting raw materials, etc., and achieve the effect of high product yield and simple process

Inactive Publication Date: 2015-09-30
徐玲琍
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] 1) Nitration of 2,4-dichloro-5-fluorobenzoic acid: Tetrahedron Letters, 50(21), 2525-2528; 2009, and DE3702393 introduce the nitration reaction of 2,4-dichloro-5-fluorobenzoic acid in mixed acid , to synthesize 2,4-dichloro-3-nitro-5-fluorobenzoic acid, the starting material of this route is not easy to obtain, the price is relatively high, and there is no economic feasibility
[0007] 2) Nitrification and oxidation of 2,4-dichloro-5-fluoroacetophenone: Journal of Heterocyclic Chemistry, 25(3), 927-30; 1988 and Tetrahedron Letters, 50(21), 2525-2528; 2009 respectively 2,4-dichloro-5-fluoroacetophenone was nitrated in mixed acid, and the prepared nitrated intermediate was oxidized in the presence of sodium hypochlorite to obtain 2,4-dichloro-3-nitro-5-fluorobenzene Formic acid, this route has many steps, and the operation is cumbersome, so it is not suitable for industrial production

Method used

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  • One pot synthetic method of 2,4-dichloro-3-nitro-5-fluoro-benzoic acid
  • One pot synthetic method of 2,4-dichloro-3-nitro-5-fluoro-benzoic acid

Examples

Experimental program
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Effect test

Embodiment 1

[0017] Add 280 grams of 90% nitric acid to the reactor, control the temperature from 0°C to 10°C, add 207 grams of 2,4-dichloro-5-fluoroacetophenone in batches, and maintain the temperature from 0°C to 10°C after adding React in a range of 4 hours, then slowly raise the temperature to 40°C and keep it for 2 hours, then slowly increase the temperature at a controlled rate, up to 110°C, and keep it at this temperature for 1 hour. After the reaction, cool down to room temperature, then add ice water, filter , collect the solid, and refine the product to obtain the product. After the nitration reaction is completed, the temperature is raised to 52°C to 152°C for oxidation reaction until the reaction is complete, and 221 grams of the product are obtained in the latter process, M.P.192~196°C.

Embodiment 2

[0019] Add 250 grams of 98% nitric acid to the reactor, control the temperature from 0°C to 10°C, add 207 grams of 2,4-dichloro-5-fluoroacetophenone in batches, and maintain the temperature from 0°C to 10°C after adding React in a range of 4 hours, then slowly raise the temperature to 40°C and keep it for 2 hours, then slowly increase the temperature at a controlled rate, up to 110°C, and keep it at this temperature for 1 hour. After the reaction, cool down to room temperature, then add ice water, filter , collect the solid, and refine the product to obtain the product. After the nitration reaction is completed, the temperature is raised to 52°C to 152°C for oxidation reaction until the reaction is complete, and 233 grams of the product are obtained in the latter process, M.P.192~195°C.

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Abstract

The invention discloses a one pot synthetic method of 2,4-dichloro-3-nitro-5-fluoro-benzoic acid. The synthetic method takes 2,4-dichloro-3-nitro-5-fluoro-acetophenone as a raw reaction material and comprises the steps of nitration, oxidation and ice melting under the participation of nitric acid to obtain the target product. The one pot synthetic method is simple in process, easy to operate, and as high as 92 percent in product yield.

Description

technical field [0001] The invention relates to a one-pot method for synthesizing 2,4-dichloro-3-nitro-5-fluorobenzoic acid. Background technique [0002] 2,4-Dichloro-3-nitro-5-fluorobenzoic acid is a very critical fine chemical and pharmaceutical intermediate, mainly used in the synthesis of quinolones and floxacins. The new quinolone antibacterial drugs listed in the 1990s include sparfloxacin, nafloxacin, levofloxacin, gepafloxacin, trovafloxacin, and alafloxacin. Among them, levofloxacin has been widely used due to its high efficiency, broad-spectrum, safety and other characteristics since it was launched on the market, and has become one of the most commonly used antibacterial drugs in clinical practice. [0003] In the late 1990s, some new varieties came out, including gatifloxacin, moxifloxacin, gemifloxacin, etc., and have entered the stage of clinical trials one after another, and some products have been officially applied in clinical practice. Because these prod...

Claims

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Application Information

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Patent Type & AuthorityApplications(China)
IPC IPC(8): C07C205/58C07C201/08C07C201/12
Inventor徐玲琍
Owner徐玲琍