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Process of preparing 2,3,4-trifluoro nitrobenzene using o-chloro nitrobenzene

A technology of trifluoronitrobenzene and o-chloronitrobenzene is applied in the field of production technology for preparing 2,3,4-trifluoronitrobenzene by using o-chloronitrobenzene, and can solve the shortage of ofloxacin raw materials. Market competitiveness, difficulty in mass production, and high cost of raw materials, to avoid diazotization reaction, small investment, and strong versatility

Inactive Publication Date: 2002-07-10
昆山虹祺药业有限责任公司
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Problems solved by technology

[0003] The present invention aims to solve the current problem that ofloxacin crude drug lacks market competitiveness due to the high cost of raw materials, the difficulty in controlling the diazotization thermal decomposition amplification, and the difficulty in mass production.

Method used

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specific Embodiment approach

[0011] The present invention is further described in detail in conjunction with the following examples.

[0012] ①, Weigh 803 grams of o-chloronitrobenzene and 16 grams of anhydrous ferric chloride, put them into a 1000 ml four-necked flask, heat with an oil bath, when the temperature rises to about 55 degrees Celsius, after the ferric chloride in the bottle is completely dissolved, pass Add chlorine gas, control the flow rate of chlorine gas, and keep the reaction temperature in the range of 90-100 degrees Celsius. With the progress of the reaction, the amount of chlorine gas introduced can be appropriately reduced, and the reaction time is maintained for 8 to 10 hours, and the chlorine gas and heating are stopped. Wash the reactant several times with hot water in the separating funnel, the material turns from reddish brown to light yellow, the organic phase is washed twice with dilute sodium carbonate solution, and then washed with hot water until neutral, and rectified to ob...

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Abstract

The preparation of 2,3,4-trifluoro nitrobenzene, the main intermediate for preparing Ofloxacin with o-chloronitrobenzene as raw material includes the steps of: chlorinizartion of o-chloronitrobenzene material, washing with washing liquid and decompressing rectification to prepare 2,3-dichloronitrobenzene; drying 2,3-dichloronitrobenzene and fluorination with KF in the presence of phase transfer catalyst; distillation to separate and to obtain fluorination product and chlorination and nitration at high temperature; and dewatering nitrified product, fluorination with KF and distillation to obtain 2,3,4-trifluoro nitrobenzene. The present invention reduces 2,3,4-trifluoro nitrobenzene producting cost greatly.

Description

(1) Technical field [0001] The invention relates to a new production process for preparing 2,3,4-trifluoronitrobenzene by using o-chloronitrobenzene instead of 2,6-dichloroaniline as a raw material, and belongs to a method for synthesizing fine chemical products. (2) Background technology [0002] 2,3,4-Trifluoronitrobenzene is the main intermediate for the preparation of ofloxacin. Ofloxacin has a wide antibacterial spectrum, strong antibacterial activity, good bioavailability, oral safety, low toxicity and side effects. It has the advantages of no drug resistance, etc., and is currently a bulk drug in clinical use. However, the domestic production of 2,3,4-trifluoronitrobenzene is based on 2,6-dichloroaniline as raw material, after diazotization, nitration, and Although fluorination synthesis has been practiced for decades in China, due to the high cost of raw materials and the difficulty in controlling the amplification of diazotization thermal decomposition, it is diffic...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C201/12C07C205/11
Inventor 王斌王皆胜
Owner 昆山虹祺药业有限责任公司
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