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Synthesis method for 2,4-dichloro-3-nitro-5-fluorobenzoic acid

A technology for the synthesis of fluorobenzoic acid and methods, applied in chemical instruments and methods, preparation of organic compounds, organic chemistry, etc., can solve the problems of cumbersome operation, high price, and difficult availability of starting materials, etc., and achieve simple process and high product quality The effect of high yield

Inactive Publication Date: 2014-12-17
江苏德峰药业有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006]1) Nitration method of 2,4-dichloro-5-fluorobenzoic acid: Tetrahedron Letters, 50(21), 2525-2528; 2009, and DE3702393 introduced 2 , 4-dichloro-5-fluorobenzoic acid is nitrated 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 it is not economical feasibility
[0007]2) 2,4-dichloro-5-fluoroacetophenone nitrification oxidation method: Journal of Heterocyclic Chemistry, 25(3), 927-30; 1988 and Tetrahedron Letters, 50(21), 2525-2528; 2009 respectively introduced the nitration of 2,4-dichloro-5-fluoroacetophenone in mixed acid, and oxidized the prepared nitrated intermediate in the presence of sodium hypochlorite to obtain 2 , 4-dichloro-3-nitro-5-fluorobenzoic 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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  • Synthesis method for 2,4-dichloro-3-nitro-5-fluorobenzoic acid

Examples

Experimental program
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Effect test

Embodiment 1

[0017] Add 280 grams of 90% nitric acid into 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 50°C to 150°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 50°C to 150°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 synthesis method for 2,4-dichloro-3-nitro-5-fluorobenzoic acid. According to the synthesis method, in the presence of nitric acid, 2,4-dichloro-5-fluoroacetophenone serves as a reaction material, is nitrified and oxidized and is subjected to calving, and a target product is obtained by treatment. The one-pot synthesis method is simple in process and easy to operate, and the product yield is 92%.

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 & Authority Patents(China)
IPC IPC(8): C07C201/12C07C205/58
Inventor 王德峰俞健钧王炳才吴迪山
Owner 江苏德峰药业有限公司